Tales of Cataloguing XIII -- the first Hazard -- epilogue
From Eric Flesch@21:1/5 to All on Sun May 9 01:01:44 2021
At bottom is my posting of 9-Jan-2019 wherein I described finding the
lost quasar "0440-168" on the basis of a strong NVSS radio source
associated to the bright blue starry object at J044240.31-164627.6.
Now, with regret, I must append that VLASS has pinpointed the radio
source to be not the blue object, but a galaxy 9 arcsec away at J044239.99-164617.9. Therefore the basis of my identification is no
Given that there are not other candidates (excepting one below), I
note that the blue object does have WISEA W1 & W2 detections, but not
W3. The blue object shows no proper motion. However, it's not
enough. I must retract it as a bonafide QSO candidate.
NED and some literature show a different object, that being a blueish
object at J044215.16 -164221.6, which in 1950 co-ordinates is
B044000.33 -164800.0 . Note that the object is almost precisely at
the NW corner of the B0440-168 rectangle of sky described fully in the
posting below. Those who took that as the object evidently thought
that "0440-168" was a precise location instead of the approximation
that it was. The object there also shows no evidence of being a
quasar (no WISE W3, no radio, etc), and subsequent investigations (of
things like lower-z absorbers) turned up empty.
Noting that Cyril, in his discussions with me, did not explicitly say
that the object "0440-1" was a quasar, I'm thinking now that it was an
early mistake -- possibly even the confluence of the galaxy and blue
object on the early grism plate -- and that 0440-168 was never a
quasar. I will annotate it accordingly in future.
Tales of Cataloguing XIII -- the first Hazard
Jan 9, 2019, 6:41:03 AM
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
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.