[vsnet-alert 7575] Re: SGR 1900+14 / bright optical counterpart

[Arne Henden <aah@nofs.navy.mil>]

Please don't get too anxious about this observation.  If you
look at the literature on SGR1900+14 (especially Vrba et al.
2000, ApJ 533, 17 and Vrba et al. 1996, ApJ 468, 225), you
will find that there is a close pair of highly reddened M stars located
at approximately
   19:07:15.2 +9:19:21.3 J2000
Since this location matches Berto's coordinates, I am sure that
he is just seeing these two stars blended, especially since he is observing
unfiltered.  You must be very careful in reddened regions.
Arne

B Monard wrote:
> Hi,
> 
> In response to alerts from several GCN circulars, the starfield of the
> suspected active transient and gamma ray burster SGR 1900+14 was imaged this
> evening at the Bronberg Observatory (South Africa), using the 12" f/4.2 SCT
> with CCD camera ST-7E.
> 
> More than 30 images with exposures of 45 sec were taken (in extremely windy
> conditions) and the best images were inspected.
> 
> By comparison to images of the Digitized Sky Survey of generation 2 / red
> and blue, a new and bright object was visible at position 19 07 15.18 +09 19
> 22.6, astrometrically traceable to the USNO-A2.0 frame.
> 
> The brightness of this new object and its neareness to the published
> coordinates (19 07 14.33 +09 19 21.1 from radio interferometry) make this
> object the probable optical counterpart of the active gamma ray burster.
> 
> Photometry of the object showed no obvious fluctuations of the brightness.
> The unfiltered CCD observation:
> SGR 1900+14   20021106.737   15.0CR
> 
> Note: on most images the object looked distinctly elongated in the E-W
> direction.
> 
> If the weather allows, follow-up observations will be done at the Bronberg
> Observatory tomorrow.
> However, the longer nights in the Northern hemisphere ought to enable
> timeseries of much longer duration on this Northern target.
> 
> This notice may be cited and communicated to the GCN network.
> 
> Berto Monard / MLF
> Bronberg Observatory / CBA Pretoria
> 
> 
> 
>

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp