[vsnet-alert 17105] Re: [BULK] Re: ASASSN-14aj: large amplitude CV candidate

Brian Skiff bas at lowell.edu
Fri Mar 28 11:35:39 JST 2014

On Fri, 2014-03-28 at 10:19 +0900, Taichi Kato wrote:
> Re: ASASSN-14aj: large amplitude CV candidate
> > large amplitude CV candidate, matches to a blue g=21.6 SDSS source, also there 
> > (V=15.1) on 2014/03/25, nothing there (V<17) on 2014/03/19
>    It is interesting that this SDSS object is not so blue
> (relatively bright in z).  What is the N magnitude in
> GSC 2.3.2?

     I think it is fairly blue, but has some foreground
extinction.  The GSC-2.3 'N' (I-band) magnitude = 15.55,
but the star is not present on the POSS-II far-red 
plate-scan at Goddard SkyView (thus fainter than I ~19).
     However, a look at the more complete Schmidt
plate-scans available at the USNO-Flagstaff server:


...shows that there are two IV-N plates that produced
the 'N' exposures.  The one dated 1995.4648 shows the star
in outburst, agreeing with GSC-2.3.  It is faint on all
the other seven plates in that archive.
     This IV-N plate (ro copy) is also the one scanned
with SuperCOSMOS, which can be accessed starting here:


...and the magnitude there is I = 15.585.  The SuperCOSMOS
catalogue gives the exposure date as 1995.466.
     Folks have perhaps already noticed there are are
two SDSS exposures in quiescence (no spectrum, alas).
The star is in fact present on the u-band exposures,
so for something that faint it must be quite blue
for it to show up at all.


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