The "Tales of Cataloguing" series on this forum were about my trail of
data fixes along the way to publishing the "Half Million Quasars
Catalogue" (HMQ), 2015 PASA,32,10. That paper has a cautionary note
at section 2.B.4 end, about use of quasars from Iovino/Clowes/Shaver, 1996,A&AS,119,265 which featured many bright & reddish objects not
typical of quasars.
But it's not satisfactory to have dud objects in the catalogue. Users
aren't going to read every word in the paper before using the data.
So I need to resolve this problem in the Milliquas catalogue (
http://www.quasars.org/milliquas.htm) which is the live version of
the HMQ.
I've remedied this as follows: Of the 1140 Iovino "quasars" in
Milliquas, 251 have radio or X-ray or WISE associations. I took those
251 as confirmed quasars and used them as a training set to create an
Iovinoi quasar profile having these constraints: optical brightness
17.5, red-blue colour (B-R)<1.6, and PSF (either R or B stellar).
Of the 889 non-associated "quasars", 659 conformed to that profile and
so are retained, whilst 230 were too bright or too reddish or had
galaxy PSF and so are dropped.
This leaves 251+659 = 910 Iovino quasars in the next edition of
Milliquas (current edition is v5.5). This will resolve the cautionary
note given in the HMQ paper. This will be mentioned in the next
ReadMe, but I post this as a more comprehensive public record.
Eric Flesch
26-Nov-2018
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