• Tales of Cataloguing XVI -- 6 positional fixes of faint legacy quasars

    From Eric Flesch@21:1/5 to All on Sat Oct 30 23:46:40 2021
    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
    and at NASA HEASARC at

    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

    (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.

    Eric Flesch
    New Zealand

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