Also, to just make a couple of quick comments about Bell 2007:
Dear FSM, how lazy was the reviewer? Seriously, how the heck (when mentioning this paper to a colleague, I used rather stronger language) did this make it into ApJ? It's terrible.
I've said elsewhere that Bell doesn't understand selection, and this absolutely proves it. He doesn't even understand
what samples went into the catalog he used!
Quote:
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Originally Posted by Bell 2007
... but whether the current VCVcat contains many AGN galaxies found in the SDSS galaxy survey is unclear.
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Hmm... If I go to SIMBAD and look at the names of the objects included in Véron-Cetty & Véron, 2006, I see several at the top of the list with "SDSS" in the name. Seems pretty clear to me. And I didn't even have to read their paper to determine that!
Strike one! Though, in truth, that's enough to completely chuck it, I'd say.
Quote:
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Originally Posted by Bell 2007
However, since AGN galaxies are easily distinguishable from other types of galaxies, the normally strict selection criteria are not required in this case to obtain a source sample that is made up almost entirely of AGN galaxies.
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Huh... Really? This is news to me. Guess there were a whole slew of posters at the latest AAS meeting that were completely irrelevant...
That statement
is true for certain classes of AGN, given
certain types of observations. And it is certainly true for luminous (optically selected, broad line) quasars. But for AGN in general? Not for any commonly used definitions of the term. I'm not familiar enough with VC-V to know whether this is a safe assumption for their catalog, but considering Bell didn't even know whether the catalog included SDSS quasars (and it took me literally 2 minutes to check, most of which was waiting for SIMBAD to load), I'm definitely
not trusting his word on it.
Strike two!
Really, those two should be enough to toss this one out on the curb. But, since I started counting strikes, here's a good choice for number 3: his use of Stickel et al. 1994 to define the "radio galaxy" sample. Certainly
FIRST is a better choice for looking at radio sources: it is uniform (as opposed to a literature search) it goes down to 1 mJy (compared to 1 Jy), has 5" resolution and includes about a million sources (compared to ~600). And it overlaps completely with SDSS, so there are optical identifications with spectra for many of the sources (a very trivial and stupid check gives ~40,000 SDSS spectra of FIRST sources). I have no idea why someone would use a much older survey to define a sample cut.
Unless Bell isn't aware of FIRST.
Which is odd, because it's one of the best large area radio surveys in currently existence.
I sense a trend here...
That makes three. Can we burn it now?