• Tales of Cataloguing XIII -- the first Hazard

    From Eric Flesch@21:1/5 to All on Tue Jan 8 12:41:01 2019
    On the way to building the Million Quasar catalogue, I had the good
    fortune of email exchanges with Cyril Hazard, a giant of the early
    quasar discovery days in the 60's-70's. Building on that, in the
    1980's Hazard discovered a large set of quasars on objective prism
    plates from the UK Schmidt telescope. He didn't publish them but lent
    them to other researchers in the 1980's -- in that time it was common
    to withhold the precise location of the quasars so that they could be
    re-used in a proprietary fashion. Accordingly, many of Hazard's
    quasars were never published, but he allowed publication of 92 of them
    in my Half Million Quasars catalogue published as 2015 PASA 32 10.

    But Cyril didn't give out all his quasars to me. One he did not, or
    would not, share was "Q 0440-168", used by multiple papers in the
    1980's. The contemporary quasar catalogues (Hewitt & Burbidge and
    Veron-Cetty & Veron) had no better position than its name -- that it
    was located in the rectangle of sky denoted by "0440-168", i.e.
    bounded by the points (B1950) 04h40m00s-16d48m00s (inclusive) and 04h41m00-16d54m00s (exclusive) -- the last digit of the name
    representing tenths of a degree.

    In our discussions, Cyril commented about this quasar: "I have the
    original finding chart in front of me now. In this, my first survey,
    it is numbered in my system as 0440-1 so clearly one of the more
    interesting objects on the plate." So I knew from Cyril's comment
    that this is a big bright quasar.

    But I could never find it in my own data. The best I could do was to
    publish it as an R=18.2 B=18.7 optical-only object at (J2000) 04 43
    03.4 -16 43 55. I thought it should be brighter, and the location is
    slightly outside the B1950 rectangle..

    My friends, the mystery is now solved -- I have found this object.
    NVSS pointed the way. I had no useful radio/X-ray association in this
    place, but when I looked up the NVSS finding chart I found one bold
    NVSS source there -- just one, but one is all I needed. My automated
    software didn't link it to any object, but when I looked there using
    the PAN-STARRS finding chart, there it was, a big bold blue boy with
    PS magnitudes r=16.87 g=17.24 -- offset 9 arcsec from the nominal NVSS
    centroid which is why my software missed it. That's the problem with automated processes, they're stupid, they only do what you tell them
    to do.

    This big boy is at (J2000) 04 42 40.30 -16 46 27.5 which in B1950
    terms is 04 40 25.6 -16 52 05, so right in the designated box of sky.
    The reason I missed it before was because my optical data calls it
    "fuzzy in red" while I'd been looking only for stellar in both red &
    blue bands -- also I didn't have the NVSS guidance. But PAN-STARRS
    shows it is just stellar. These things happen with big data. Good to
    have finally found this. It is included in the latest edition of my
    Milliquas catalogue, just released today on https://heasarc.gsfc.nasa.gov/W3Browse/all/milliquas.html .

    I'll tell some more discovery stories shortly. Next one is about
    finding charts -- is it a quasar or is it a red dwarf? Coming.

    Eric Flesch

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