Tales of Cataloguing series 2011-2021 by Eric Flesch on the newsgroup sci.astro.research (a selection below plus some replies) ______________________________________________ Subject: Tales of Cataloguing Newsgroups: sci.astro.research From: Eric Flesch Date: Thu, 20 Oct 2011 13:16:09 GMT I was bemused to see a recent paper, 2011A&A.,529,99, Cupani G. et al, "When two become one: an apparent QSO pair turns out to be a single quasar". The authors found that two objects in the Veron quasar catalog were in fact just one object, and provided a likely audit trail for how the error came to be. OK, it was useful for my own quasar cataloguing, but a 3 page paper for this? It is just that in the course of cleaning data for my "million quasars" catalogue, I've found & fixed maybe a hundred bloopers recorded in Veron and NED. It's just that the early quasars from the 1970's and 1980's are rife with inexactitude, to where imprecision blurs with error. But I've not considered publishing the fixes beyond recording the correct information in my catalog. An interesting topic (well, to some) is the improvements in resolution from those days to now. Back then, you espied an 18th magnitude quasar in a 1-degree tile of sky, named it e.g. "0150-535" (z=1.56) and moved on, knowing that anyone who looked later would recover it easily enough. Never mind the wag who came along later and re-discovered it with greater precision as "0147-537" (z=1.568). There are a number of such objects in the Veron catalog, annotated as having "approximate positions", which are nominally just placed in the center of such tiles of sky, because no better position is known. In the end I became pretty good at finding the right optical object for these, using the available optical, radio and X-ray data. But some puzzlements remain. There is one publication which eluded me entirely, Afanas'ev et al, 1990BSAO,32,51 presenting quasars named SA68 #110,SA68 #105,SA68 #090,SA68 #094,SA68 #143,SA68 #095,M82 #95,M82 #69,M82 #22,SA57 #216,SA57 #431. My friends, I could not find these objects at all -- as though the authors made them all up. The given co-ordinates point to nothing. I searched near and far for hours -- there was nothing. If anyone knows the whereabouts of these objects, could they contact me. I have removed them from the "million quasars" catalog until they are found. I'll resist boring you with more such stories, but I do requests. Eric Flesch ___________________________________________________________________ Subject: Tales of Cataloguing II Newsgroups: sci.astro.research From: Eric Flesch Date: Mon, 24 Oct 2011 09:16:07 GMT This is part 2 of anomalies I've encountered in cleaning QSO data. 99 44/100 % is fine. This is the story of the remaining 0.56%. The task in producing the "million quasars" catalog is to find the right optical object for each quasar. If the data positions a brightish quasar but I find no optical object there, then I must search for it. Any feedback welcome. Section A: When Veron 13th edition and NED disagree, Veron usually wins because of the careful attention of its authors. But not always, and following are 5 cases of mixed outcomes. 1) HE 0435-1223 (this old notation describes a B1950 tile of sky): a Cyril Hazard quasar -- he rarely published positions for these. Veron positions this at J043814.8-122314, NED has J043814.8-121715. NED is right -- Veron failed to convert the declination from B1950 to J2000. 2) IXO 40: Veron positions this at J115057.9-290043 but there is nothing there. NED has J115057.9-284402, which is right. Veron was off by exactly 1000 arcsec in declination, indicating a transcription error. 3) NGC 2859 U2, a Halton Arp quasar. Veron positions this at J092457.8+343952, in the middle of nowhere. NED has J092557.6+343950 which is correct. Veron has a transcription error of 1 time minute = about 900 arcsec. However, NED also has a "NGC 2859 U02" at the bogus location, so NED has a duplicate here. 4) NGC 2859 U3, much like (3), above. Veron has J092454.2+341648 which is off by 1 time minute. NED has J092554.0+341645 which is correct, but also has "NGC 2859 U03" at the bogus location, thus, again, a duplicate. 5) SBS 1014+565, a Soviet quasar: Veron correctly has this at J101724.4+562108. SDSS-DR7 re-surveyed this at the Veron location but erroneously called it "SBS 1014+566". NED has had SBS 1014+565 at the bogus location of J101715.0+561811 (not sure why), and has added the bogus-named "SBS 1014+566" at the true location given by SDSS-DR7, so NED has a duplicate here. Section B: bright Soviet quasars from Afanasjev et al,1979AN,300,31. This paper published 4 quasars, one of which, TB 0933+733, z=2.525, had a finding chart. A pity they didn't all have one, for 3 anomalies follow. (TB=Tautenburg objective prism survey, H. Lorenz) 1) TB 0748+611, z=2.492 v=17.5 is in NED as [HB89] 0747+613 at J075212.0+611223. However, that optical object is v=20.0 and at B074750.1+612006 is in 0747+613, not 0748+611. Investigation finds this object listed in Veron & NED as SBS 0747+611, z=2.487 v=17.2 at B074801.9+610537, ie J075222.6+605753. So the NED object [HB89] 0747+613 is duplicate. I will restore the original name TB 0748+611 in the next edition of the million quasars catalog. 2) TB 0948+722, v=17.5, z=0.529: Veron says J095224.6+715755 but this is only the centre of a 400-arcsec square tile of sky. I found this quasar at J095254.2+715803, 171 arcsec from the nominal location. It is an in-your-face v=17.2 quasar with X-ray 2RXP J095255.1+715758. 3) TB 0958+735, v=17.5, z=2.067: Veron says J100225.4+731532, but as with (2) this is only approximate. This is again an in-your-face v=17.1 quasar at J100317.6+731559 at 180 arcsec from the nominal location. It has X-ray 1RXS J100317.6+731558 and radio NVSS J100318.7+731558. More to come, Eric Flesch _________________________________________________________________ Subject: Tales of Cataloguing III -- duplicate quasars Newsgroups: sci.astro.research From: Eric Flesch Date: Thu, 27 Oct 2011 10:56:38 GMT Following are a list of 21 duplicates found in the Veron catalog. Where these objects also appear in NED, I add the NED name. May I preface by saying that the Veron catalog is a tremendous resource, and the Verons did a fantastic job. If there were a few slips of the fingers in the course of producing a 130,000-object quasar catalog, well, they were jolly well entitled. I've loosely sub-categorized these by whether the duplicates are long-established, or recently created by SDSS re-surveying of old objects. Section A: 13 contemporary duplicate quasars These are long-standing doppelgangers of the same quasars, due to imprecise or erroneous co-ordinates. In each case one entry is found to be right and the other wrong. 1) Q 0450-132 (J045218.9-130503 v=17.5 z=2.253, NED name:[HB93a] 0450-132) does not exist, and is a duplicate of H 0450-1310 (J045313.6-130555 v=17.4 z=2.250) at a distance of 788 arcsec. The earlier 0450-132 (1988) was given an approximate position of B045000.0-131000 (ie, J045218.9-130503), and when subsequently (2004) surveyed more precisely, the linkage was not made. (X-ray XMMX J045313.5-130554) Back in B1950 days, it was obvious that the B1950 position was approximate, but conversion to J2000 has imbued such co-ordinates with a false precision which cloaks the original intent. This theme often repeats below. 2) Q 1211-1056 (J121346.0-111314 v=19.0 z=1.626, NED:[VCV96] Q 1211-1056) does not exist, and is a duplicate of TEX 1212-109 (J121446.0-111313 v=19.4 z=1.626, NED:PMN J1214-1113). The offset is exactly 1 RA time-minute, indicating an error in transcription. Note that the correct name of this object is Q 1212-1056 as given by the discoverers Osmer & Hewett, 1991-ApJS-75-273, table 3A #58, and thus written that way into the Million Quasars catalog. (radio NVSS J121446.0-111313) 3) 1H 0150-535 (J015223.6-532034 v=18.5 z=1.560) does not exist, and is a duplicate of H 0147-537 (J014852.8-532829 v=17.4 z=1.568, NED:LASS 0150-535) at a distance of 1944 arcsec. Remillard et al, 1993-AJ-105-2079 reported these as the same object (table 1, top row), but the cataloguers seem not to have noticed. NED uses a variant of the old name for the true object. 4) TEX 0121+035 (J012435.3+034731 v=19.6 z=0.221) does not exist, and is a duplicate of MS 01200+0328 (J012236.8+034356 v=18.2 z=0.221, NED:[HB89] 0122+035 NED01) at a distance of 1787 arcsec. The problem is that TEX 0121+035 was erroneously given the co-ordinates of the nearby galaxy NGC 520. Note however that this object's correct name is NGC 520.46, as given by the discoverer Halton Arp in 1985-PASP-97-1149 which displayed a finding chart. This original name has been written into the Million Quasars catalog. (X-ray 2RXP J012236.6+034349) 5) BR 0035-25 (J003758.7-251331 r=18.9 z=4.15, NED:[VCV96] BR 0035-25) does not exist. It has an approximate B1950 position, B003530.0-253000 ( = J003758.7-251331). Author Mike Irwin advises that it is duplicate to BRI J0048-2442 (J004834.5-244205 r=19.0 z=4.15), with a typo causing the false separation from the early approximate B1950 name of 0045-25. 6) SDSS J0112+0053 (J011230.0+005329 v=20.2 z=4.566) does not exist, and is a duplicate of SDSSp J11228+0053 (J112253.5+005329 v=21.8 z=4.560, NED:SDSS J112253.49+005329.8) at a distance of 10 time-hours. Oops, wrong end of the sky! It appears that the Verons got tripped up by their truncated notation, and interpreted "11228" as "011228". This object is SDSS J112253.50+005329.7, in the DR7 quasar catalog with z=4.551. 7) SDSSp J1517+0101 (J151730.0+010130 v=19.2 z=2.004) does not exist, and is a duplicate of SDSS J15171+0101 (J151707.6+010112 v=19.3 z=2.007, NED:SDSS J151707.62+010112.2) at a distance of 336 arcsec. The bogus object was taken from Richards et al, 2001-AJ-121-2308 which described preliminary SDSS work and gave no positions -- apparently the Verons "data-mined" the name "SDSSp J1517+0101", using the B1950 tile method to derive a position at the centre of the J2000 tile 1517+0101, ergo, J151730.0+010130. This "object" was not subsequently re-visited and so was orphaned when the true object appeared later. 8) Q 0128-367 (J013041.8-363133 v=17.4 z=2.169, NED:[HB89] 0128-367) does not exist, and is offset 3463 arcsec from the true object Q 0123-3648 (J012554.5-363235 v=18.1 z=2.164, NED:[HB89] 0123-368). Cause: "0128-3647" was published in 1993-ApJS-88-357, but it would appear that the true notation was "0123-3647", but the original handwritten 0123 was read as 0128. 9) SDSS J03464+0037 (J034629.0+003700 v=19.1 z=2.770, no NED) does not exist, and is offset 803 arcsec from the true object SDSS J03464+0023 (v=19.7 z=2.770, NED:SDSS J034629.01+002337.6). Cause: Looks like a Veron truncation error, as the full declination is "002337", and the true truncation is "0023" and the false one was "0037", so it looks like the wrong pair of digits were taken. 10) SDSS J07464+2449 (J074625.8+244901 v=15.5 z=2.979, no NED) does not exist, and is offset by one degree N/S from the true object SDSS J07464+2549 (J074625.8+254901 v=19.7 z=2.979, NED:B2 0743+25). Cause: Veron truncation error, declination of 2549 was written as 2449. The original name "B2 0743+25" is recorded in the Million Quasars catalog. 11) FIRST J09510+2210 (J091203.8+221051 v=17.6 z=0.220, no NED) does not exist. NED has the true object as FBQS J095159.9+220906 (v=17.3 z=0.220). The physical offset is over 9 degrees, even though the RA-based offset of the names is just 10 time-minutes, ie, 2½ degrees. This is because the bogus object is not only named badly, it's placed wrongly for its name. Cause: gremlins/grandchildren in the laboratory? Chaos left its signature on this one object. 12) SDSS J10479+0739 appears twice in the Veron catalog. The correct line shows the object SDSS J104755.92+073951.2 v=19.8 z=0.168. The incorrect line apparently was meant to be named "10469+0739" as it shows J104656.0+073952 v=19.3 z=0.168, which however does not exist. Cause: looks like a working line which was meant to be deleted, but was not. 13) RX J14462+2541 (J144615.5+254143 v=17.3 z=0.188, no NED) does not exist, and is offset by 2 time hours (30 degrees E/W) from the true object SDSS J16462+2541 (J164615.6+254143 v=19.5 z=0.189, no NED). This is an AGN-galaxy of integrated v=17.0, SDSS J164615.54+254143.1 having X-ray 1RXS J164616.0+254129. Cause: the object is from Veron-Cetty et al, 2004-A&A-414-487 table 4, where it is recorded at J164615.52+254143.3, but when entered into the Veron catalog, the second digit of the RX name was erroneously written as 4 instead of 6. Section B: 8 SDSS-orphaned objects The following 8 quasars are old B1950 objects with approximate co-ordinates, whether tiles-of-sky or arcminute precision, which were recently orphaned when SDSS re-surveyed them at precise co-ordinates, and the connection was not made that they are the same object. In each case I have written the old original name onto the updated object in the Million Quasars catalog. 1) Q 0837+109 (J083943.6+104321 z=3.326 NED:[HB89] 0837+100) is the same object as SDSS J08402+1034 (v=18.5 z=3.331, NED:SDSS J084017.88+103428.9) at a distance of 734 arcsec. The earlier location was just the corner of the B1950 tile of sky 0837+109, thus B083700.0+105400 = SDSS J084017.87+103428.8, a DR7 quasar. 2) LB 8814 (J085314.5+184737 v=18.6 z=0.183 NED:[HB89] 0850+189) is the same object as SDSS J08533+1847 (v=19.0 z=0.182 NED:SDSS J085322.44+184713.9) at a distance of 115 arcsec. The earlier object's co-ordinates were in B1950 arcminutes. I have restored the original name "LB 8814" into the Million Quasars catalog. 3) PSS J1118+3702 (J111856.2+370200 v=18.8 z=4.030, no NED) is the same object as SDSS J11189+3702 (v=20.3 z=4.025 NED:SDSS J111856.15+370255.9) at a distance of 1 arcminute N/S. 4) Q 1510+115 (J151223.8+111847 v=. z=2.106, NED:[HB93a] 1510+115) is the same object as SDSS J15128+1119 (v=17.8 z=2.110, NED:SDSS J151249.29+111929.3) at a distance of 378 arcsec. The old object had the approximate co-ords B151000.0+113000. 5) Q 1511+091 (J151325.9+085450 v=. z=2.878, NED:[HB93a] 1511+091) is the same object as SDSS J15138+0855 (v=17.8 z=2.904, NED:SDSS J151352.52+085555.7) at a distance of 400 arcsec. The old object had the approximate co-ords B151100.0+090600. 6) Q 1159+01 (J120133.8+004318 v=. z=3.269, NED:[VCV96] Q 1159+01) is the same object as SDSS J12017+0116 (v=17.7 z=3.233, NED:SDSS J120144.36+011611.5) at a distance of 1979 arcsec. The old object had the approximate co-ords B115900.0+010000. 7) NGC 5866#1 (J150628.4+554530 v=18.1 z=0.706, NED:[HB89] 1505+559) is the same object as SDSS J15057+5549 (v=18.4 z=0.709, NED:SDSS J150543.86+554935.9) at a distance of 449 arcsec. The old object had the approximate co-ords B150506.0+555700. This is a Halton Arp quasar, now also SDSS J150543.89+554936.1, a DR7 quasar. 8) Q 1159+00 (J120203.8+001318 v=. z=2.586, no NED) is the same object as Q120220.06+002242.1 (v=17.4, z=2.580, VLT-LBG Crighton N. et al, 2011-MNRAS-414-28) at a distance of 615 arcsec. The old object had the approximate co-ords B115930.0+003000. This VLT-LBG survey is post-Veron but I include it here for completeness. Next up: Far-Flungers, a.k.a., You thought that quasar was *where*?!? :-))) Eric Flesch ______________________________________________________________________ Subject: Tales of Cataloguing IV -- far-flungers Newsgroups: sci.astro.research From: Eric Flesch Date: Sun, 30 Oct 2011 08:24:05 GMT IV. ** far-flungers -- misc moves over 10 arcmin ** So you look up a brightish quasar on DSS or SDSS-DR8 finding charts but are greeted by empty sky. What now? In my case, in constructing the Million Quasars catalog, I needed to find each optical object. Available clues are object brightness (if provided), expected color, and local radio/X-ray maps & photometric NBCKDE/XDQSO quasar candidates. NBCKDE also provides photometric redshift so can point to a compelling candidate if the magnitude is also right. In this way I've identified hundreds of nearby optical objects which are the obviously correct quasar. Usually these objects are within an arcminute and there is no issue. But they can be farther, and indeed some of them are far-flungers of 10 arcminutes, or 20, or a degree, or 4 degrees, or even, my friends, thrown into the other hemisphere when one hemisphere is not enough. So without further ado I present such objects. Section A: 7 Far-Flungers -- true objects > 10 arcminutes from catalogued position. 1) Q 0229+0656 (J023204.5+070954) is moved 972 arcsec to J023204.8+072606, and renamed to 0229+0712. No magnitude is given for this blank-sky object (z=0.903, NED:[VCV96] 022925.7+065641). The discovery paper 1993-ARep-37-466 names it as 0229+0712 while stating a position of B022925.71+065641.3 -- note the misfit of the name with its declination. The Verons' technique was to use the position as master, thus changing the name to 0229+0656. However, the original name B0229+0712 denotes a tile of sky in which I found the true object, v=17.9, radio NVSS J023204.7+072605, X-ray 1RXS J023204.1+072611. I've restored its original name "0229+0712" in the Million Quasars catalog. 2) NGC 2639 C2.4 (J084449.6+542306) is moved 4 degrees south to J084445.2+502253. This Halton Arp quasar (v=19.4 z=2.63, no NED) must be near the galaxy of its name, NGC 2639, but this Veron location is far away. Arp's co-ordinates ("Seeing Red",Apeiron,1998,table 3.2) are exactly 4 degrees to the south, and near the galaxy, indicating a Veron transcription error. 3) XBS J14496-0908 (J144936.6-090829) is moved 18 degrees into the Northern Hemisphere at J144936.6+090830 -- change the "-" to "+". This happened because the original publication "The XMM-Newton Bright Serendipitous Survey", Caccianiga A. et al, 2008-A&A-477-735, mispositioned their object XBSJ144937.5+090826 at 144936.61-090829.6 (note the name is N, the position S). The Verons evidently used the given co-ordinates both for position and truncated name form. The true optical object is v=19.5, z=1.26, no NED. 4) Q 2342+089 (J234433.0+091039) is moved 865 arcsec to J234531.0+090906. This is once again an approximately-located object -- Veron flags these, in case you don't want to work out the B1950 position which here is B2342000+085400, i.e., RA=23.7 hours, decl=8.9 degrees. This object has no magnitude given, z=2.784, NED:[HB89] 2342+080. Inspection reveals an in-your-face quasar, v=18.2, X-ray CXOX J234531.0+090905. 5) Q 1052+04 (J105505.2+041400) is moved 1592 arcseconds to J105510.1+034730. This v=18.1 object (z=3.391, no NED) has an approximate position centered on the sky-tile B105200.0+040000, so the true object can be offset by up to 900 arcsec RA and 1800 arcsec decl. NBCKDE J105510.14+034730.0 (=B105235.0+040331, v=18.5) seems to be the only suitable v=18 candidate, and looks good except that its photometric redshift is only 0.535. However, v=18.1 is quite bright for a z=3.391, and Veron's catalog paper 2010-A&A-518-10 explains (illustrated by its figure 2) that old z=3.3 redshifts (specifically z=3.3) were often wrong because low-z MgII-2800A lines were mistaken for Lyman-alpha. Therefore I have marked J105510.1+034730 as "Q 1052+04" in the Million Quasars catalog. 6) Q 2334+10 (J233702.5+104636) is moved 1065 arcsec to J233731.2+110253. This is an approximately-positioned unpublished Cyril Hazard quasar without a magnitude, z=2.243, NED:[VCV96] Q 2334+10. Hazard quasars are generally flat-spectrum v=18, and two candidate objects are found in this tile of sky, BOSS J233731.23+110253.0 (v=18.4) and SDSS J233730.66+105759.9 (v=18.0). The BOSS project considers the "BOSS" object as a science-primary object (i.e. it will be observed) and the other is not, so on this slender reed I record the BOSS object as "Q 2334+10" in (the next edition of) the Million Quasars catalog. 7) Q 2351+10 (J235403.4+104642) is moved 834 arcsec to J235341.0+105926. This is another approximately-positioned unpublished Hazard quasar, the centre of the tile B233400.0+100000, no magnitude, z=2.379, NED:[VCV96] Q 2351+10. There is only one eligible object which fits the Hazard quasar profile, it is BOSS J235341.05+105926.6, v=18.4. This object has been named Q 2351+10 in the Million Quasars catalog. Section B: 7 true objects 2-9 arcminutes from the catalogued position. 1) Q 0047-2326 (J004957.7-230940 v=. z=3.422, NED:[VCV96] Q 0047-23) is moved 198 arcsec to J005012.0-231000. Another approximately-located unpublished Cyril Hazard quasar. Optical v=18.2. 2) PSS J0052+2405 (J005230.0+240530 v=17.4 z=1.90, no NED) is moved 366 arcsec to J005204.2+240708, and renamed as PSS J0052+2405 (#2) because Veron has two objects of this name. Original position was approximate to 400 arcsec. Optical v=18.4. 3) NGC 157#1 (J003446.3-082347 v=19.0 z=0.756, NED:[VCV96] NGC 157 1) is moved 326 arcsec to J003521.6-082500. Halton Arp quasar, approximately positioned. Optical v=19.8. 4) Q 0112-381 (J011508.4-375106 v=19.0 z=2.28, NED:[HB89] 0112-381) is moved 230 arcsec south to J011508.2-375336. An Ann Savage quasar, with finding chart (plate 13) supplied in 1984-MNRAS-207-393. These finding charts are not easy to read and I'm guessing this one slipped past the Verons. 5) Q 0124-365 (J012704.2-361903 v=19.0 z=1.61, NED:[HB89] 0124-365) is moved 220 arcsec to J012717.6-361835. Also an Ann Savage quasar, same paper and finding charts. The finding chart for 0124-365 was typed as "0124-355" and pen-corrected to "0124-365" but still looks like "355". The finding chart is sparse, with only 3 objects. I think the Verons couldn't find this one -- they did not mark it as optically seen. Took me a while to find it. 6) Q 1532+2332 (J153438.1+232230, v=19.8, z=1.249, no NED) is moved 10 time sec, ie, 137 arcsec, to J153448.0+232232. This is a Halton Arp quasar from Arp H, Burbidge EM, Chu Y, Zhu X, 2001-ApJ-553-L11, table 1, object "Arp 9", which gives the correct co-ordinates. The Verons somehow copied the "48.1" time-seconds as "38.1". 7) Q 2239-386 (J224221.7-382017 v=. z=3.554, NED:[VCV96] Q 2239-386) is moved 232 arcsec to J224237.0-382049. This is an approximately-located unpublished Cyril Hazard object, much the same as ones above. This tile of sky shows no Hazard-pattern flat-spectrum v=18 objects, and the high z=3.554 implies a fainter object. There is one standout object, J224237.0-382049 v=19.8 with X-ray 1RXH J224237.1-382047, and nothing else comes to hand, so this one is selected. Section C: 5 Veron quasars deleted 1-3) "Optical Transients" are here today, then gone forevermore. The current thinking is that they are novae. Three Veron objects were optical transients: Q 0000-029 (v=18 z=2.31, NED:[HB89] 0000-029) and Q 2355+003 (v=19 z=2.84, NED:ZC 2355+003, from 1986-A&A-160-321) and ROTSE J11568+5427 (v=18.1 z=1.02, no NED, from Astronomer's Telegram board) which was mis-positioned by Veron, but it makes no difference as it does not exist. 4-5) Satellite streaks -- two SDSS objects, SDSS J09557+2525 (SDSS J095546.30+252534.8 z=2.262) and SDSS J10162+2649 (SDSS J101615.16+264902.4 z=0.383) were found by DR8 to be satellite streaks and removed. Obvious if you have a look. Section D: 7 Veron quasars moved 1-2 arcminutes. I'll just give the correction for the record. 1) Q 0154-500 (J015607.0-494531 v=18.7 z=2.46) moved about 70 arcsec N to J015606.8-494423 (v=19.2) 2) 2E 0237+3953 (J024100.7+400721 v=18.3 z=0.528) moved 103 arcsec to J024054.7+400606 (v=18.5) 3) TOL 1313-309 (J131628.7-311149 v=18.0 z=0.048) found ~1 arcmin away at J131632.6-311218 (v=17.8) 4) 3C 295.0 (J141120.5+521110 v=19.8 z=0.461) actually 1 arcmin North at J141120.4+521210 (v=19.5) 5) 2E 2141+0400 (J214407.8 v=20.6 z=0.401) moved 1 arcmin to N at J214408.0+085902 (v=19.2) 6) Q 2217+0844 (J222008.7+090002 v=17.6 z=0.228) moved 61 arcsec S to J222008.6+085902 (v=17.9) 7) G 2344-3852 (J234649.2-383520 z=0.041) 80 arcsec W to J234643.8-383521 The Weedman catalogs from 1985-ApJS-57-523 and 1978-ApJ-221-469 (Sramek & Weedman) provide positions typically needing correction by ~30 arcsec to their finding charts. However, Wee 140 was found to be a star by SDSS-DR5, SDSS J160250.34+280541.4. The last posting of this series will showcase ~12 mystery objects that I could not locate. Half of them I moved to an unsure matching object, the other half I deleted as not existing. I will describe each in the hope that someone will have help for them one day. Eric Flesch __________________________________________________________________ Subject: Tales of Cataloguing V -- mysteries (help welcomed) Newsgroups: sci.astro.research From: Eric Flesch Date: Fri, 04 Nov 2011 08:34:22 GMT This last posting (in the series of 5) shows 5 mystery objects and also 5 tidy-ups of objects not covered in the previous postings. Section A: Mysteries. Here are 5 objects where I couldn't be sure where the true object was. In 4 cases I moved them, flagged with a '?'=fingers crossed, or '??'=fingers crossed on both hands, and one I deleted as unseen and unknown. Any help appreciated on these objects; I'd be glad to have confirmed positions for them. 1) Q 1013+1126 (J101609.7+111102 v=17.6 z=2.22, NED:[VCV96] Q 1013+1126) was approximately-located to a 400 arcsec x 400 arcsec tile of B1950 sky, but no object there looks eligible. The discovery paper Stocke J et al, 1984-ApJ-280-476 names it as H 1013+113 (a Hazard quasar) with v=18.5, thus a bit different than Veron. Using the paper's information, I look in the tile of sky centred on B101330.0+112100, but there is no prominent object. However, there is just one fine optical match, of v=18.5 at J101606.5+110651, so I assign that object as H 1013+113, restoring the original name. I've flagged it with a '?'. 2) 2E 1510+3902 (J151230.7+385051 v=19.0 z=0.228, NED:[HB89] 1510+390), a Gail Reichert AGN, is found to be the same object as the SDSS-DR4 AGN "SDSS J151224.30+385112.7" (v=18.2 z=0.202) at a distance of 78 arcsec. Normally the 10% offset in redshift would disqualify this match, but the paper 1982-ApJ-260-437 cited this object (in table 5) as having uncertain attributes due to being the only Kitt Peak observed object and a spectroscope of small aperture, and did not present a redshift chart for this object, in contrast to most objects which did show charts. Reichert's objects all show X-ray, and this SDSS object does have ROSAT 2RXP J151224.7+385112. Inspection of the surrounding sky shows nothing else suitable to a radius of 15 arcminutes. Therefore I have assigned this object as 2E 1510+3902, but have flagged it with a '?' due to the .026 redshift offset. 3) E 2352+073 (J235520.5+073257 v=19.3 z=0.277, NED:[HB89] 2352+072) is a Gail Reichert quasar from the same paper as (2). The object as described doesn't exist. The presented B1950 co-ordinates are of the Einstein X-ray detection, not the optical object. They found a v=19.3 object for it, but I see nothing eligible. There are no X-ray objects nearby; there is one 15 arcmin due west, but it is v=22 so far too faint. In the end I suspect a positional error, so I check all objects within a degree. At J235205.7+074111 there is a perfect match, it is a v=19.4 blue stellar object with X-ray RASS 1RXS J235204.2+074105. Due to lack of an alternative, I assign this object as "E 2352+073", flagged with '??' because of the unexplained large offset of 2939 arcseconds. 4) Q 0752+617 (J075622.4+613401 v=. z=1.892, NED:[VCV96] Q 0752+617) is an approximately-positioned (B075200.0+614200) Soviet quasar. Near the centre of its tile of sky is an optically suitable object of vmag=17.1, J075646.6+613639. The lead author, V. Afanasjev (1989 SvA Letters 15 83) specialized in finding mag 17 quasars, and there are no other eligible objects in this tile of sky. Still, he did not give a magnitude and there are no other indications. I assign this object as "Q 0752+617", flagged with '??' because of the assumption of v=17 and no other indications. 5) IRAS 22040+0332 (J220634.2+034655 v=. z=0.064, no NED) is deleted as unseen. It was one of two AGNe reported by Gu Q et al, 1995-ChAA-19-289; the other was precisely located, this one points to nothing, even in the SDSS-DR8 finding chart. No magnitude or finding chart presented. This IRAS object is not found elsewhere. No NVSS radio objects in the vicinity. It is tempting to conflate it with IRAS 22017+0319 (J220419.1+033351 v=14 z=0.066) at an offset of 2169 arcsec, but no basis for doing so. This object is deleted as unknown and unseen. Section B: 4 objects deleted and 1 object moved for satisfactory reasons. I'm not needing help with these, but of course any extra information about them would be gladly received. 1) MC 1227+120 (J123003.3+114910 v=19 z=0.061, NED:[VCV96] MC 1227+120) deleted as not existing. This object was published in a 1977 quasar catalog (Burbidge G, Crowne A, Smith H, 1977-ApJS-33-113) with reference given to a paper "in press", that paper being Smith H et al, 1977-ApJ-215-427. However, this object does not appear there. Looks like they changed their minds about it, and MC 1227+120 is a stillborn orphan. Deleted. 2) RXS J14194+4518 (J141925.0+451832 v=16.7 z=0.076, no NED) deleted as duplicate to the AGN z=0.075 SDSS J142925.07+451831.7 which has X-ray RASS 1RXS J142924.3+451826. Looks like the RASS RA 1429 was mis-recorded as 1419, especially as there is no RASS detection of that name. Deleted. 3) RX J11062+0237 (J110613.7+023758 v=17.1 z=0.564, no NED) deleted as not existing. This object was presented in Veron-Cetty et al, 2004-A&A-414-487, but its position therein is quite different, at J111507.7+023757, and so refers to the RASS detection 1RXS J111507.2+023802. That detection is associated to the DR7 quasar SDSS J111507.65+023757.5 (v=17.2 z=0.566) which is obviously the same object. Evidently RASS names got confused. Deleted. 4) 1ES 1249+174W (J125142.2+171153 v=18.5 z=0.644, no NED) deleted as not existing. From Perlman E et al, 1996-ApJS-104-251, wherein two objects were presented for the Einstein Slew X-ray detection 1ES1249+174. One of these is catalogued as 1ES 1249+174E (J125145.4+171117 v=18.4 z=0.650, an SDSS DR7 quasar). The other "candidate" is this unseen object which was described in the discovery paper as a "BL candidate" and not assigned a redshift. The catalogued redshift of 0.644 actually belongs to the E object, the SDSS quasar. This object, the W object, was mis-catalogued and does not appear to exist at all. Deleted. The E object is recorded in the Million Quasars catalog as "1ES 1249+174", no "E" required. 5) Pavo 1#4 (J211559.0-675715 v=19.8 z=0.408, no NED) is moved 6 arcmin north to J211558.4-675115. The "-6751" as reported in Danziger & Gilmozzi 1997-A&A-323-47, was Veron-inscribed as "-6757". NED doesn't have these. All changes described in these five "Tales of Cataloguing" have been placed into the Million Quasars catalog, http://quasars.org/milliquas.htm http://heasarc.nasa.gov/W3Browse/all/milliquas.html although a few of them are earmarked for the next edition v2.7, due soon. These five postings were done to place all these changes on the record, invite comments, and assist in any future published documentation. Eric Flesch 4 November 2011 ___________________________________________________________________ Tales of Cataloguing VI -- fire sale Eric Flesch Oct 1, 2013, 4:22:35AM An example of the wages of cataloguing: Today's new paper ArXiv:1309.7048 by 18 authors "Finding Rare AGN: XMM-Newton and Chandra Observations of SDSS Stripe 82" announces as a highlight the discovery of "the highest redshift (z=5.86) quasar yet identified in an X-ray survey", their X-ray source being CXO #165442 which is CXO J000552.3-000655, associated to a faint magnitude 25.6 optical object. But, errr, I've had that X-ray source associated to that optical object in my catalogue since early 2010, at 95% certainty. Heck, I've got a z=6.305 associated to CXOX J103027.1+052454 at 99% certainty. OK, my quasar catalogue may be mirrored on NASA, but it's not peer-review published. But I expect to publish some of it one day, but that won't change anything. Fire Sale on catalogued information! $0.00 to a good home! cheers, Eric ----------------------------- Phillip Helbig Oct 2, 2013, 7:22:51PM In article , Eric Flesch writes: > OK, my quasar catalogue may be mirrored on NASA, but it's not > peer-review published. Why not? ------------------------------ Eric Flesch Oct 3, 2013, 3:36:41AM On Wed, 02 Oct 13, Phillip Helbig wrote: >Why not? It's taken me this long to resolve a great many issues. My plan is to publish a half-million quasar catalogue in 2015, after the last BOSS release in December 2014 -- presuming we've reached a half million by then. I originally thought I'd wait til a cool million is reached, but that's going to take a very long time -- 2025 is my guess. Eric __________________________________________________________ Tales of Cataloguing VII -- QSOs in pokes Eric Flesch Oct 18, 2013, 8:56:24PM In the April 2013 release of the Million Quasars catalogue v3.3, I removed 144 "quasars" which I had sourced from the classic VCV13 quasar catalogue(2010,A&A,518,10). These objects were originally from Iovino et al, 1996 A&AS,119,265 which presented 1581 quasar spectra, but marked 144 of them as "?". I became aware of these outliers because many of them were anomalously bright, and investigation showed that none of the144 had any radio or X-ray association, whereas 66 of the other 1437 did have. Thus, if the "144" are all true quasars, the chance of none having radio/X-ray is (1371/1437)^144 = 1/10th of 1%. Therefore it is 99.9% likely that they are not all true quasars. Further numerical analysis reveals that no more than 14 are likely to be true quasars. So I removed them all. In this way it became clear that the Verons had been a little too, er, inclusive in their collection. So recently I have investigated more doubtful objects from VCV13 by consulting the original discovery papers, and have found about 700 more to remove, as follows: (1) Schneider/Schmidt/Gunn 1994 AJ 107,1245 published 928 objects of which, they stated, 305 were quasars of z>0.68 and 623 were emission-line galaxies (ELGs) of z<0.45. However, all (not pre-empted by other surveys) were taken up as quasars by VCV13. I have now removed 484 of these ELGs. (2) Similarly, Schneider/Schmidt/Gunn 1999 AJ 117,40 published 96 objects of which 55 were ELGs of z<0.45, all taken up by VCV13 as quasars. Those 55 ELGs are now removed. (3) Papovich et al, 2006 AJ 132,231 published a large list of many object types. VCV13 selected the quasars among these, but also took up 13 ELGs / type-2s as being type-1 QSOs, which I have now removed. (4) the 2dF-GRS galaxy survey (Colless M. et al, astro-ph/0306581) did not publish quasars, although some authors, notably Madgwick D. et al, 2002 MNRAS 334,209 did mine it for quasars. However VCV13 evidently did some mining of their own, promoting 63 2dF objects with nominally high redshift into quasars. I've inspected many of these on DSS, and confusion with neighbours is common. However, 5 of the objects are quasar-like with radio/X-ray association. The remaining 58 have been removed. (5) La Franca F. et al, 1999 A&AS 140,351 published a large list of quasars but excepted some objects as galaxies. VCV13 took up the lot. I have removed 41 galaxies, thanks to NED for differentiating them as the paper is not on ADS for some reason. I selected these papers as those showing large numbers of anomalous objects, so these are all that I have done. More work will have diminishing returns. I'll do more when someone funds me. :-) By the way, NED too has been naughty in places. Their "quasars" with names starting with FPT and [LPK2009] (about 40 in total) were from papers showing galaxies in the fields of quasars -- those galaxies promoted to quasars in NED -- and demoted back out of the Million Quasars catalogue. Eric Flesch Wellington, New Zealand ------------------------------ jacob navia Oct 19, 2013, 7:30:24AM Hi Eric In his book "The static Universe", (1) Hilton Ratcliffe publishes a table of 40 quasars with verified proper motions (page 107). He provides an online reference: http://www.site.uottawa.ca/~tcl/factguru1/astronomy/1982SST.....5..521V.pdf You get to that PDF from http://www.laserstars.org/V1982/index.html Just click in the "Also available in Adobe Acrobat PDF format." link at the top of the page and look at table 2. Could you please have a look Eric? As an expert in these matters, you can maybe confirm/infirm this: Are some "quasars" MOVING? You yourself found that some quasars had "wrong coordinates", and I remember proposing you that maybe those quasars are moving... Now, investigating this highly heretical subject, I have found these references, that are surely worth some of your time... Could it be that those quasars with "wrong coordinates" were just moving ones? Of course (if they move) I do not think that your observations have the necessary time depth to observe actual movements but MAYBE if you look again at one of the quasars where you "fixed" the coordinates, and see a small discrepancy it could be... well a movement? Thanks in advance, and when you receive the Nobel for this discovery please do not forget to invite me to a beer :-) jacob ----- (1) The static Universe. Exploding the myth of Cosmic Expansion. Hilton Ratcliffe. Edited by Apeiron, Montreal. ISBN 978-0-9864926-2-4 Very heretical astronomy book available at Amazon. Of course I do not endorse all theories proposed there, I lack the necessary background to really assert what is going on. But a fascinating reading for people that like the science of astronomy --------------------------------- Phillip Helbig Oct 20, 2013, 8:57:26PM In article , jacob navia writes: > In his book "The static Universe", (1) Hilton Ratcliffe publishes a > table of 40 quasars with verified proper motions (page 107). There is a tad of irony here. (OK, I haven't read the book. Probably by "static" he means "not expanding" and uses large(?) proper motion of QSOs to argue that they are not at cosmological distances, thus "challenging the paradigm".) Of course, if quasars were really ejected from nearby galaxies at high speed, we WOULD see significant proper motion. At some level, almost all quasars should have some proper motion. If your resolution is good enough to measure it, then probably the quasar will no longer be a point source, but has a definite shape, which changes with time. So, it is difficult to define a fiducial point whose motion one can detect. That doesn't mean that it is impossible, but realistic proper motions will probably be swamped out by such effects, at least on the timescales we have access to now. ---------------------------------- Eric Flesch Oct 20, 2013, 8:58:21PM On Fri, 18 Oct 2013, jacob navia wrote: >In his book "The static Universe", Hilton Ratcliffe publishes a >table of 40 quasars with verified proper motions (page 107). >http://www.site.uottawa.ca/~tcl/factguru1/astronomy/1982SST.....5..521V.pdf That article dates from 1980 and it is important to note that astrometric precision was far less then than today. So, as with the canals of Mars, it was easier to fool oneself. > table 2. Could you please have a look Eric? Sure, and I will preface my remarks by saying that checking on proper motion is a trivially simple thing to do, because we have all-sky images available from different epochs. Specifically, the Digitized Sky Survey (http://archive.stsci.edu/cgi-bin/dss_form) gives us sky cut-outs from the POSS-I survey (epoch 1950s-1960s) and the POSS-II survey (epoch 1980s). We also have SDSS finding charts from epoch late-2000s, such as the SDSS-DR9 finding chart tool (http://skyserver.sdss3.org/dr9/en/tools/chart/chart.asp). Therefore we can select any object and see its position at each of those epochs. But let's look at a few of these, and rather than trawling through table 2 for objects, suppose I select out the three mentioned in the abstract as being of most note, these are: PHL 1033 located at (J2000) 01 33 43.2 +03 57 36 LB 8956 at 08 57 26.7 +18 55 24 LB 8991 at 08 58 30.1 +18 37 07 For these three, I've taken an SDSS-DR9 finding chart for the 2005 epoch, and a DSS POSS-I cut-out for the 1960 epoch, and you can see each epoch side by side at these 3 addresses: http://quasars.org/goodies/PHL 1033.jpg http://quasars.org/goodies/LB 8956.jpg http://quasars.org/goodies/LB 8991.jpg You will see how much better the SDSS (left side) resolution is compared with the POSS-I (right side) resolution, but I've scaled them to the same size, 3.5 arcminutes on a side. I trust you will not take long to satisfy yourself that these 3 quasars have not moved at all, not even a little bit. Since I've shown you where to get these finding charts, and how to do it, you can therefore check out the individual objects of table 2 for yourself, and test for movement. I daresay your results will not vary. Still, the news isn't all bad. Some quasars do indeed move. But it depends on what you call a "quasar". How about this for a definition that even the most learned amongst us could agree on: A "quasar" is an object classified as a quasar by the SDSS-DR10 release at http://www.sdss3.org/dr10 . Good, eh? So let's look at a couple of their quasars: (1) http://quasars.org/goodies/SDSS J090514.88+090424.2.jpg These 3 images are POSS-I 1950s epoch on the left, POSS-II 1980s epoch in the centre, and SDSS-DR10 2008 epoch on the right. Observe the bright quasar near the centre of each photo, see how gayly it moves across the stellar background. Then there's this: (2) http://quasars.org/goodies/SDSS%20J014519.68+231752.6.jpg First 2 images on left are red & blue from POSS-I (1950s), the next 2 images are red & blue from POSS-II (1980s), and the right-hand image is from SDSS (2008). Observe how the quasar and an M-star (red) companion are moving in tandem, a stately procession from right to left across the stellar background. So yes, quasars do move. But, err, that means they weren't quasars at all. Well golly gosh darn, those are white dwarf stars. But their spectra looked quasar-like enough to fool the SDSS-DR10. This is, firstly, because the DR10 is an automated survey which makes mistakes, and, secondly, because sometimes the spectral quality isn't the best and we can't be sure which it is, a quasar or a star. Then if we see that it moves, as these two examples do, then we know know that it is indeed a star after all. So the bottom line is, if we find that a quasar is moving, then we know that we were wrong to classify it as a quasar, and that it is instead a star. You probably wouldn't find that to be a very satisfactory outcome to your query, and indeed it isn't very satisfactory, but it's the best we can do when working with faint objects and faint spectra. However, in the 1980 paper that you cited, note the reviewer's appended remarks at the end where he makes the excellent point that if quasars were stars, then we should expect to see most of them in the Galactic disk -- but instead, we see them out the Galactic axes where extragalactic visibility is best. Hope this has helped, Eric Flesch --------------------------- Phillip Helbig Oct 21, 2013, 9:07:29PM In article , Eric Flesch writes: First, great response, Eric. I'm sure that clears everything up! > So yes, quasars do move. But, err, that means they weren't quasars at > all. Well golly gosh darn, those are white dwarf stars. But their > spectra looked quasar-like enough to fool the SDSS-DR10. This is, > firstly, because the DR10 is an automated survey which makes mistakes, > and, secondly, because sometimes the spectral quality isn't the best > and we can't be sure which it is, a quasar or a star. Then if we see > that it moves, as these two examples do, then we know know that it is > indeed a star after all. > > So the bottom line is, if we find that a quasar is moving, then we > know that we were wrong to classify it as a quasar, and that it is > instead a star. You probably wouldn't find that to be a very > satisfactory outcome to your query, and indeed it isn't very > satisfactory, but it's the best we can do when working with faint > objects and faint spectra. Just to be clear, this is not a tautology. Many white dwarfs are actually found as mis-classified quasars, and stellar astrophysicists follow them up with high-resolution spectropscopy etc. So, the fact that it moves does not ipso facto make it a non-quasar, but rather is a strong hint that it is not a quasar, and this is confirmed by followup observations. ------------------------------ jacob navia Oct 21, 2013, 9:11:55PM Excellent answer Eric, thanks a lot. I will write to Mr Ratcliffe to see what he has to say about this, but the argument of quasars not being in the galactic plane is a very strong one. Thanks again. ------------------------------- Jonathan Thornburg Oct 21, 2013, 9:13:59PM Indeed, there are lots of VLBI observations of time-variable substructure in quasars. A few examples plucked at random from an ADS search: 3C 263 http://adsabs.harvard.edu/abs/1996ApJ...464..715H NRAO 150 http://adsabs.harvard.edu/abs/2007A%26A...476L..17A I'll say more about this below. But there's a larger issue: high-precision absolute astrometry [measurement of the ABSOLUTE position of an object with respect to some fundamental reference frame, i.e., the sort of measurement you need in order to measure proper motions] is *very* difficult and horribly prone to systematic errors -- it involves looking for *tiny* shifts in position over a period of many years, and there are all too many instrumental effects that can mimic these position shifts. I think it's fair to say that almost all astrometry experts think Ratcliffe's claims are NOT valid. While I (and almost all astrophysicists) have a strong Bayesian prior that quasars are very distant and hence have only very tiny proper motions, it's still a reasonable question to ask how one could test this. First, a cautionary tale: In 1935 Van Maanen claimed to have measured the proper motion of stars in nearby spiral galaxies: http://en.wikipedia.org/wiki/Adriaan_van_Maanen http://adsabs.harvard.edu/abs/1972QJRAS..13...25H These observations used optical photographic plates. In hindsight the plate measurements were wrong (systematic errors > claimed proper motions). More recently, ESA's Hipparcos mission did high-precision absolute astrometry on ~120K stars from space, avoiding many of the systematic errors of ground-based measurements. Alas, quasars are relatively faint optical sources, while Hipparcos could only detect relatively bright sources. Apart from a marginal detection of 3C 273, Hipparcos didn't directly observe any quasar. Radio stars were used to tie the Hipparcos reference frame to quasars http://adsabs.harvard.edu/abs/1998ASPC..144..381L but I don't know if this explicitly tested whether the quasar system was internally a "rigid body". With today's technology, radio VLBI is the best ground-based way to test whether quasars have nonzero proper motions. Some interesting papers on this include: * MacMillan http://adsabs.harvard.edu/abs/2005ASPC..340..477M explicitly looked for proper motion in a large VLBI data set, but concluded "The problem, however, is to how to determine how much [of] the observed apparent motion is due to unmodelled source structure effects." * Titov et al http://adsabs.harvard.edu/abs/2011A%26A...529A..91T detected the drift in quasar positions due to our Sun's orbital motion about the center of our galaxy * Bartel et al http://adsabs.harvard.edu/abs/2012ApJS..201....3B) describe observations done specifically to test whether certain quasars are moving with respect to each other. The answer is basically no to within ~ 20-50 microarcseconds/year, limited by time-variable substructure. ESA's Gaia mission is due to launch very soon (the current plan is for late November). This should do high-precision absolute astrometry on ~1e9 objects, including ~500K quasars. Gaia should be able to set limits on proper motion down to the ~20-200 microarcsecond/year range, depending on the object's brightness. -------------------------------------------- Phillip Helbig Oct 22, 2013, 8:23:19?PM In article , Jonathan Thornburg writes: > But there's a larger issue: high-precision absolute astrometry > is *very* difficult and horribly prone to systematic errors -- it > involves looking for *tiny* shifts in position over a period of many > years, and there are all too many instrumental effects that can mimic > these position shifts. Agreed. > I think it's fair to say that almost all astrometry experts think > Ratcliffe's claims are NOT valid. > > While I (and almost all astrophysicists) have a strong Bayesian prior > that quasars are very distant and hence have only very tiny proper > motions, it's still a reasonable question to ask how one could test > this. Note that Arp claims that certain quasars have been ejected from certain nearby galaxies. In such cases, a relative proper motion between the galaxy and the quasar would prove his claim. (Of course the galaxy has its own proper motion, but if Arp's claim is true, the relative proper motion between quasar and galaxy a) would be quite large, much larger than the average proper motion of a nearby galaxy and b) would be in the direction of the vector connecting the two.) > More recently, ESA's Hipparcos mission did high-precision absolute > astrometry on ~120K stars from space, avoiding many of the systematic > errors of ground-based measurements. Alas, quasars are relatively > faint optical sources, while Hipparcos could only detect relatively > bright sources. Apart from a marginal detection of 3C 273, Hipparcos > didn't directly observe any quasar. Radio stars were used to tie the > Hipparcos reference frame to quasars > http://adsabs.harvard.edu/abs/1998ASPC..144..381L > but I don't know if this explicitly tested whether the quasar system > was internally a "rigid body". There was also some work, by Christian de Vegt and colleagues, using optical observations to tie the Hipparcos frame to the quasar frame. With photographic plates, they could just get astrometry-quality exposures of faint hipparcos stars and bright quasars on the same plate. This was done in Hamburg while I was there, probably one of the last scientific observing programs at a sea-level optical observatory. ------------------------------------- Steve Willner Oct 24, 2013, 7:50:45PM In article , Jonathan Thornburg writes: > With today's technology, radio VLBI is the best ground-based way to test > whether quasars have nonzero proper motions. A network of quasars defines the International Celestial Reference Frame for Earth's rotation. See http://iers.org and in particular http://www.iers.org/nn_10404/IERS/EN/Science/Techniques/vlbi.html?__nnn=true If any of the >600 reference quasars had proper motion, that would be obvious in the data. ___________________________________________________________________________ Tales of Cataloguing VIII -- the log of jumping up & down Eric Flesch Nov 7, 2013, 9:03:46PM Doing final tidy-ups for the final time -- yeah, right. Move a few, de-dup a few, then I find this: Q 2112.8+0594, a quasar catalogued in VCV13 onto an entirely unsuitable optical signature at 21 15 18.0 +06 08 32. What's more, there's a fine-looking R=18.6 B=18.6 just 23 arcsec away at 21 15 16.6 +06 08 41, and it has X-ray 3XMM J211516.5+060840 too! OK, let's take a closer look. The original paper is, hmm, 1991-ApJS-76-455, Ellingson/Yee/Green. Does that ring a bell? It does! That paper has a bogus finding chart for Q 2347+005 on the last page -- I annotated that in my paper 2013-PASA-30-4 -- their finding chart was wrong, but the co-ordinates in their very large Table 3 were right, so the correct object was able to be retrieved. They couldn't have done that twice in one paper, could they? Let's see... There it is, last page of the paper again, first finding chart on it, 2112+059. Hmm, VCV13 was right about the object they marked on the finding chart. So, let's look at the massive Table 3, page 468 (huff puff), last section, 2112+059, says (B1950) 12 12 47.50 +5 56 10.0. Looked at this for a while before it dawned on me that it's supposed to say RAh=21, not RAh=12. Heh, OK, let's correct that and transform it to J2000 --> 21 15 16.6 +06 08 41 -- BANG!!! Well waddayaknow, my X-ray object is the one they meant! Boy they sure did a great job hiding it. Hid it for 22 years, until now. Hey, what was the story with those finding charts on the last page? Late with the manuscript, publisher awaits? Just mark anything and get it out the door? Sheesh! I could tell more stories about duplicates etc but mindful that only the deranged could care... (that's me, by now :-) Eric ------------------------- Steve Willner Nov 22, 2013, 8:05:24PM In article , Eric Flesch writes: > what was the story with those finding charts on the last page? Late > with the manuscript, publisher awaits? Just mark anything and get it > out the door? Sheesh! Well, a blunder is a blunder; no excuse then or now. Still, things were a lot harder in the old days with no electronic help. Finding charts were made by hand measurements using Palomar Observatory Sky Survey prints on which one arcminute is less than a millimeter. For most telescopes, blind pointing accuracy was an arcminute or worse. More romantic, I suppose, but in terms of producing accurate results, those "good old days" weren't so good. ____________________________________________________________________ Tales of Cataloguing IX -- VCV13 fixes for the record Eric Flesch Nov 9, 2013, 11:54:10PM I've done some more cleanups of the VCV13 (2010,A&A,518,10) quasar catalog. These are different to those I published in 2013,PASA,30,4 as those were for objects unmatched to any optical signature, whereas these are fully mapped to optical, but to the wrong ones. There aren't many of these and I'm not going to write a paper for them, but I think that these fixes should be placed into the public record. Therefore I post them here, and full publication will be within my half-million quasar catalog to come in 2015. I herewith present 4 de-duplications and 8 moves (>12 arcsec) of quasars which VCV13 fixed onto the wrong optical object -- usually because of errors or unclarity by the original authors (OA). I'll explain each, all co-ordinates are J2000. FOUR DE-DUPLICATIONS: (1) Q 03020-0014, z=3.05, v=21.5 at 03 04 35.3 -00 02 25 is duplicate to SDSS J03045-0002 (i.e. SDSS J030435.33-000251.0), z=3.061, r=20.3, b=20.5 at a distance of 26 arcsec. The OA were Jakobsen P. et al, 2003-A&A-397-891 who included a finding chart not seen by VCV (early editions sometimes omit plates), and so VCV positioned the object 26 due north of its actual location. (2) RX J09278+3431, z=0.425, v=17.8 at 09 27 48.1 +34 31 02 is duplicate to SDSS J09278+3431 (i.e. SDSS J092751.11+343103.6), z=0.426, r=17.8, b=18.1 at a distance of 37 arcsec. The OA were Wei J-Y. et al,1997-ChA&A-21-146 which isn't on ADS but NED confirms that VCV13 faithfully reported this quasar as writ. The "RX" name shows that this object was selected via X-ray association -- however, this object is an obvious galaxy (or star-galaxy doublet) with no X-ray detection nearby. The SDSS quasar, of the same redshift, has X-ray association with 97% confidence (2RXP J092751.1+343102, 1RXS J092750.7+343034). It is clearly the intended object. (3) 1WGA J0958.0+4903, z=0.242, v=18.7 at 09 58 04.4 +49 03 08 is duplicate to SDSS J09580+4903 (i.e. SDSS J095802.85+490311.0), z=0.242, r=17.5, b=18.2 at a distance of 14 arcsec. From Molthagen/Wendker/Briel 1997-A&AS-126-509 (not on ADS), the name shows selection via X-ray, but, as with (2), this is not seen with today's data. Instead, the SDSS quasar, of the same redshift, has X-ray association (2RXP J095803.1+490317, 1WGA J0958.0+4902), and is clearly the intended object. (4) RXS J11479+2715, z=0.364, r=18.0, b=19.4 at 11 47 54.4 +27 15 00 is duplicate at an offset of 57 arcsec to US 2964, z=0.363, r=16.3, b=16.4 at 11 47 58.5 +27 14 59. From Bade N. et al, 1995-A&AS-100,469 (their object 109), which presented this as the optical match to a ROSAT source with an error radius of 49 arcsec, but they selected the wrong object because today's data shows no nearby X-ray detection. US 2964, confirmed by SDSS-quasar-DR7 as a quasar of the same redshift, is seen to match to X-ray 1RXS J114758.4+271507 with 87% confidence -- note this is the same RASS detection that RXS J11479+2715 was named after. EIGHT MOVES: (1) IRAS 00029-1424, z=0.440, positioned onto blank sky, is moved 12 arcsec to 00 05 29.5 -14 07 48 which has radio NVSS J000529.0-140747. The OA provided no finding chart. (2) IXO 58, z=1.194, r=19.1, b=19.9 is moved 13 arcsec to SDSS J122927.80+080630.5, r=18.9, b=19.7, identified by SDSS-DR10 as a quasar with z=1.190, and has X-ray 3XMM J122927.7+080630. From Gutierrez & Lopez-Corredoira 2005-ApJ-622-L89 which presented a correct finding chart but VCV13 took an adjacent object on the slit. (3) Q 1339.3+2716, z=1.754, vmag=20.5 (but positioned onto r=18.8, b=20.8 -- clearly unsuitable photometry) is moved 20 arcsec to 13 41 37.8 +27 01 54, r=20.0, b=20.5 which is an SDSS photometric quasar (NBCKDE J134137.77+270153.0) with radio FIRST J134137.7+270152. From Crampton D. et al, 1988-AJ-96-816 which positioned this mid-way between these two optical objects, and, uniquely for a quasar discovery paper, provided a finding chart of stars but not of quasars. (4) 2E 1416+2523, z=0.674, rmag=14.0, bmag=16.5 is moved 32 arcsec to SDSS J141857.63+250948.6, rmag=17.9, bmag=18.6 which SDSS-DR10 found to be a quasar of z=0.674 (i.e., the same), and has X-ray 3XMM J141857.5+250948 & 1RXH J141857.5+250953. From Stocke, J. et al, 1983-ApJ-273-458 which set out to find optical sources for Einstein X-ray detections. Stocke found a triplet of objects which he dubbed A,B, and C, and pronounced B the source with z=0.674. You meant C, John, argh! I am moving the name "2E 1416+2523" onto this object in the Million Quasars catalog to reward the Einstein satellite's hard working staff. (5) PKS 1418-064, z=3.689, r=17.9, b=19.3 is moved 21 arcsec onto the BZCAT blazar BZQ J1421-0643, same redshift, r=19.1, b=20.7 with radio FIRST J142107.7-064355 and X-ray CXOX J142107.7-064356. From Savage & Bolton, 1979-AuJPA-46-19, looking for optical objects for radio sources, but is not on ADS. The object presented in VCV13 has no radio, and the switch is obvious because the blazar has the same rare redshift. (6) Q 1532+01/2, z=0.31, r=16.1, b=17.4 is moved 92 arcsec to SDSS J153456.20+013032.3, a SDSS-quasar-DR7 quasar of z=0.308, r=17.2, b=18.4 with X-ray 3XMM J153456.2+013032. From Wilkes, B., 1986-MNRAS-218-331 who gave no finding chart or astrometry whatsoever and undoubtedly baffled the Verons who, if they ever threw a dart onto a sky chart, would have done so here. (7) CF 1549+48A, z=1.962, r=19.6, b=21.7 (patently unsuitable photometry) is moved 23 arcsec to 15 51 06.6 +48 29 08, r=19.5, b=19.6 which is an SDSS photometric quasar (NBCKDE J155106.59+482908.2). From Arp & Surdej, 1982-A&A-109-101 who presented a finding chart which however had such low resolution and shallow photometry that these objects could not be distinguished. (8) Q 2112.8+0594, z=0.398, r=18.7, b=21.1 (patently unsuitable photometry) is moved 21 arcsec to 21 15 16.6 +06 08 41, r=18.6, b=18.6, X-ray 3XMM J211516.5+060840. The full sad story of this object was given in the preceding post of this series, but in short the OA Ellingson/Yee/Green 1991-ApJS-76-455 mangled both finding chart and co-ordinates, now recovered. I expect no more fixes of VCV13 remain, mindful that I've said this before. ___________________________________________________________________ Tales of Cataloguing XIV -- the 0th finding chart Eric Flesch Jan 10, 2019, 6:56:25PM (This and the previous posting are because I've recently found & fixed a few more mis-positioned legacy objects -- there's always more if you look hard enough, it seems. I give the more interesting ones here, for the record.) 20th century quasar discovery papers made liberal use of finding charts to display the precise location of new quasars, lest the listed co-ordinates weren't accurate enough. Astrometry had much improved by the 1990s but finding charts were still usually included, more as a tradition than a necessity. That was all fine so long as the listed astrometry and finding chart agreed. But sometimes they didn't. Sometimes they pointed to different objects. I've given examples of this in earlier postings in this series, notably #VIII "the log of jumping up & down" which is what you do when bad finding charts drive you crazy. But other times it is good finding charts which save the day when the listed co-ordinates are false, e.g., the quasar "TOL 1038.2-27.1" from Bohuski & Weedman 1979,ApJ 231,653, object #23 (last one in the list), 41 arcsec offset from the false listed co-ordinates (unsuitable photometry r=18.0 b=20.1) to the true finding chart object (r=19.2 b=19.5). Another example is the quasar "Q 0111-328" from Savage et al. 1984,MNRAS 207,393, which gave finding charts onto the original prism (grism) plates which are infallibly correct because the actual discovery spectrum is pointed at; the B1950 co-ordinates given in the microfiche were of a nearby object offset by 76 arcsec. Even big names like Schneider/Schmidt/Gunn did this for one object, "PC 0027+0515" in 1999, AJ 117,40, the Table 5 co-ordinates of which pointed near random objects whilst the true object was revealed on the finding chart at an offset of 17 arcsec. So there were bad finding charts and good finding charts. But then there's this, from Borra et al. 1996, AJ 111,1456, the quasar "Q 13034+2942" (called "130324+294245" in the paper) is the very first one on their list, and their first finding chart. They would make no error on the very first object, right? Of course not. Furthermore, on their Table 4a they lead right off with it as positioned at B1950 130324.21+294245.8, lest there be any mistake. That translates to J2000 130547.40+292643.0 which shows up on the SDSS finding chart as a flattish-spectrum 21-mag stellar-psf which my own data reports as a variable object which was 19th magnitude in the 1960's -- so very quasar-like and all good. So why did I previously have it catalogued as a reddish v=22 object 17 arcsec to the South-West? Let's have another look at that finding chart, the first finding chart of the paper. There it is, but wait, they are pointing to the reddish object (which is probably a red dwarf star). This is one of those finding charts where they don't use a photo, instead they re-create it with ink on paper. Looks like they used a plotter (remember those?) and optical data. Um, guys, your optical data did not include the true object. It's not there at all. They're pointing to the red dwarf because the quasar isn't on the chart. Their very first finding chart for quasar discoveries points to a red dwarf star. Looking at my archived catalogue versions, I originally had the right identification (inherited from VCV) but switched it to the red dwarf just before the publication of my Half-Million Quasars catalogue. Guess I'd looked at one finding chart too many. Well, that's no kind of first finding chart to have, is it? Maybe if the authors can "promote" it to the zero-eth finding chart, it will go away. And these are the kinds of Finding Chart Follies that I've encountered through the years. ------- On a separate note, the Soviet quasar "Q 0752+617" from Afanasiev/Lorenz/Nazarov 1989, SvAL 15,83 does not exist. I've looked for it for years. I've communicated with the lead author and he doesn't know where it is -- he knows only the old VCV location which is just the B1950 sky rectangle denoted by "0752+617". There is no radio, no X-ray, no WISE candidate, no suitable bluish optical. The paper stated narrow emission lines -- perhaps they measured a galaxy. I give up, it is removed from the Milliquas catalogue as of the next edition. I will gladly restore it if the authors provide its location. Eric Flesch ____________________________________________________________________ Tales of Cataloguing XV -- last fixes in from the cold Eric Flesch Jan 29, 2019, 6:44:38PM When fixing catalogue errors one naturally wants to catch them all, but when in so doing you start to encounter new errors caused by your own recent fixes, that shows it's time to (1) clean up all your own errors, and (2) stop. This is why this set of fixes of legacy VCV (Veron-Cetty & Veron v13, 2010-A&A-518-10) quasars, placed here for the record, are truly the last of this "Tales of Cataloguing" series. These changes will appear in the next edition of the Million Quasar (Milliquas) catalogue. (1) Abell 293 was originally thought to be a (Parkes) radio galaxy cluster but Gioia et al. 1984-ApJ-283-495, in addition to discovering a background X-ray quasar with z=1.897 and v=19.7, reported that "also present in this field is a strong point radio source PKS 0159+034 whose position is not coincident with any of the X-ray or optical sources discussed here". In spite of this, VCV assigned both the name "PKS 0159+034" and the redshift 1.897 onto the primary Abell galaxy, thus conflating three objects into one. Gioia et al. provided a finding chart of the quasar but didn't name it, however they placed it as the SE component of an Einstein-detected extended X-ray emission named "1E 0159.1+0330", therefore I've added this quasar (not previously catalogued) with name of "1E 0159.1+0330 SE". Furthermore, my Milliquas algorithm shows the radio source PKS 0159+034, aka FIRST J020151.4+034309, to be associated with 98.6% confidence to a r=21.8 g=22.1 stellar source which is furthermore calculated as 96% likely to be a quasar. But it has no redshift so will continue to appear in Milliquas as a candidate only, henceforth annotated with the name PKS 0159+034. (2) While checking over legacy quasars with unsuitable photometry, I came across the quasar "A4/22" from the "Very Faint Quasar Survey", D. Schade, 1991-AJ-102-869 -- the quasar is listed with z=1.045, v=20.00 and b=20.17. But upon inspection on an SDSS finding chart, the near object is seen to be just a small passive galaxy, so how did David Schade come to call that a quasar? I've seen this situation many times before, so I look for nearby objects, and I look North, South, East, West. And sure enough, at 200 arcseconds due South of the designated spot I see SDSS J110205.85+295914.7 with g=20.00, r=19.71 and u=20.25, a perfect photometric fit. Furthermore, it is a quasar candidate in Gordon Richards' NBCKDE-v3 catalogue (2015-ApJS-219-39) with a photometric redshift of 1.000, well-matched to Schade's spectroscopic redshift of 1.045. Somehow this object got moved ~200 arcsec due North in the preparation of the paper -- looking at Table 4 of the paper, it looks like the declination of the object a4/5 was accidently copied over to a4/22. These things happen. I have moved the identification of "A4/22" over to J110205.85+295914.7, and the author has been informed. (3) LMA 15, in the IC 1613 region, was surveyed by Lequeux/Meyssonnier/Azzopardi 1987-A&AS-67-169 who provided a finding chart which however was too coarse to allow precise identification of the designated object. The astrometry was given but only to whole time seconds, so had an uncertainty of ~15 arcseconds. VCV placed it at the given RA of B010239 (a faint star triplet), the true RA is found to be B010239.9, a blue stellar g=20.7, r=21.2 (PAN-STARRS) for a move of 13.7 arcseconds. (4) KP 1229.0+07.8 from Sramek & Weedman, 1978-ApJ-221-468, #19 on their list, z=1.93, v=20.5. The B1950 astrometry, duly reported by VCV, pointed to nothing (~25 arcseconds away from 3 nearest optical candidates). A coarse finding chart was provided from which, many years ago, I selected the wrong object, SDSS J123134.02+073440.2, a galaxy with r=19.25, g=20.61. I have now moved this to the correct object, SDSS J123134.53+073425.8 with r=21.73, g=21.96, a move of 16.3 arcseconds. Besides the flatter spectrum, it is also clearly a better match to the finding chart, although you do need to stare at it for a while. Done with these now, Eric Flesch 29-Jan-2019 ___________________________________________________________________ Tales of Cataloguing XVI -- 6 positional fixes of faint legacy quasars Eric Flesch Oct 31, 2021, 7:46:43PM The Million Quasars (MILLIQUAS) catalogue v7.3 has been released, which has all quasars published to 31 October 2021. It and its ReadMe are available at http://quasars.org/milliquas.htm and at NASA HEASARC at http://heasarc.gsfc.nasa.gov/W3Browse/all/milliquas.html Part of its updates were tweaks of the J2000 for very faint (r>22) legacy quasars, i.e., those inherited from the Veron-Cetty & Veron (VCV) quasar catalogue, 13th edition. I've checked about 300 of these against Pan-STARRS and DES charts, resources which were not available until recent years. I've corrected positional discrepancies which were usually in the range of 0.5 - 2.5 arcsec. But there were a few farther offset because of errors made by the authors or by VCV. In line with previous postings in this "Tales of Cataloguing" series, I present here 6 corrections of > 10 arcsec in order of greatest offsets; 3 of these are basically lost objects, now recovered. (1) CXOPS J042155.0+330037, z=1.125, is at 04 21 55.04 +33 00 36.3 (J2000), it was published by Rogel+ 2006-ApJS-163-160. Somehow, VCV wrote RA as 042105.0 (05 instead of 55), resulting in a 629 arcsec offset (50 time sec) from the true. Now fixed, but NED does have the correct position. (2 & 3) AMS03, z=2.698 at 17 13 40.19 +59 27 45.8, and AMS04, z=1.782 at 17 13 40.57 +59 49 17.0, are both type-II objects from Martinez-Sansigre+ 2006-MNRAS-370-1479. Somehow, VCV wrote their time-seconds as 14 instead of 40, so both objects were offset about 200 arcsec from the true. Now fixed, but NED does have the correct positions. (4) ISO J1324-2016, z=1.50, is at 13 24 47.25 -20 16 12.0 (J2000) which is from Pierre+ 2001-A&A-372-L45 -- which is to say, from the authors' finding chart. What the authors actually wrote as the position was 13 24 45.67 -20 16 11.3 (J2000), which points to nothing and is 21.3 arcsec offset from the true. The false position was faithfully reported by VCV and NED. This correction recovers this quasar after 20 years MIA. (5) Q 03022-0023, z=2.14, is at 03 04 46.11 -00 11 27.5 (J2000) and is from Jakobsen+ 2003-A&A-397-891. The paper was focused on another object and briefly stated (end of section 2) a faint emission QSO at 03 04 45.94 -00 11 38.2. Nothing is seen there on DES or Pan-STARRS -- clearly the astrometry was done hurriedly. NED reports the false position. 10.8 arcsec to the NE is a flat-spectrum object, r=22.14, g=22.28, with 97% x-ray 4XMM J030446.0-001127. It is the quasar, salvaged after 18 years MIA. (6) PC 0027+0525, z=4.099, r=21.7, g=24.7, is from Schneider/Schmidt/Gunn 1997-AJ-114-36; they wrote the position as 00 27 15.4 +05 25 30 (B1950) which converts to 00 29 49.96 +05 42 04.4 in J2000. However, nothing is seen there, and NED reports this false position. However, the authors also gave a finding chart on which the quasar is seen at the true position of 00 29 49.99 +05 42 14.5 (J2000) at 10.6 arcsec offset. Thus it is recovered after 24 years MIA.