[vsnet-chat 5923] (fwd) IBVS 5342 and V379 Pegasi

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

(fwd) IBVS 5342 and V379 Pegasi

   Attached is John Greaves' message and Skiff's comment on V379 Peg.
Since Yamaoka-san has examined this field closely to get the proper motion,
I hope he will have some comment on this finding.

From: "JG" <jg@jgjs.freeserve.co.uk>
Date: Fri, 24 Jan 2003 18:08:40 +0000
Subject: re IBVS 5342 and V379 Pegasi

Dear Authors

I read with interest your paper on the nature of V379 Pegasi.

Investigating survey images derived from 

www.nofs.navy.mil/data/fchpix

I noticed something interesting.

[These images may still be available at the temporary store

http://vsnet.nofs.navy.mil/tmp/fchaayrda_fch.html

but if not are readily re-ordered]

The blue J plate survey images show an extended object immediately 
below the candidate star for V379 Pegasi (having used live Downes and 
Shara CV catalogue for co-ordinates).

It is near in brightness to plate limit, but it is evident on _all_ 
four J plates (this object is relatively well sampled in the surveyrs 
in comparison to most regions of the sky, with 6 blue and 6 red 
plates and 4 far red plates).  This suggests it is not a plate 
blemish, as each plate is dated differently.

It also appears on the F plate images, possibly being slightly 
fainter on these.

I have no idea as to whether or not a galaxy could be responsible for 
the type of spectral anomalies discussed in your paper, being 
unfamiliar with galactic spectroscopy, but I present it for your 
interest, as I feel it at least needs discounting.

There is nothing in galaxy catalogues at this position that I can 
find, but I would not really expect there to be given the faintness 
and size of the object and the adjacent bright star.  However, there 
is nothing in the NVSS at this point either, and I suppose a radio 
source could be expected if it was a galaxy.

Further, I have insufficient tools for properly enhancing such images 
with which to confirm if this is an extended object, although it does 
not look like a bunch of faint stars to me.  (In that context I cc a 
copy of this mail to Dr Skiff, who in the past has advised me on 
faint galaxy - star differences in such plates, having far more 
experience in such things than I).

Hopefully of interest


Yours

John



John Greaves

Date: Fri, 24 Jan 2003 11:55:13 -0700 (MST)
From: Brian Skiff <Brian.Skiff@lowell.edu>
Subject: Re: re IBVS 5342 and V379 Pegasi

John,
     Spectroscopy turns out to be very sensitive to surface brightness
of whatever is dispersed.  Thus something even, say, two magnitudes fainter
than the target is not likely to show any evidence on a spectrum that
includes it.  Since the variable star is so much brighter than the
underlying galaxy, I seriously doubt it would have any effect on the
resulting spectrum.

\Brian

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