[vsnet-alert 7574] Re: SGR 1900+14 / bright optical counterpart

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

Re: SGR 1900+14 / bright optical counterpart

> 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.

   I would presume that this object is a normal M-type giant, which is
not the counterpart of the SGR.  There is a finding chart in Vrba et al.
(1996) ApJ 225, 230.  This red star is a double star, which explains
the slightly elongated appearance on Berto's image.

   This red star is slightly variable (Vrba et al. 1996), having V=24.5,
which explains the absence on DSS images.

IRAS19048+0914 190451.9 +091435 (1950.0)
    F12=3.02  F25=5.75  F60=9.12  F100=39.80 
    VAR= 8 LRS=-1
    VIII: different sort of object
190715.1 +091919 (2000.0) IRAS19048+0914 3.064 5.811 9.227 38.150 8%
190715.1 +091919 (2000.0) SSC19048+0914 3.064 5.811 9.227 38.150
190715.1 +091921 (2000.0) MSX5C_G043.0229+00.7626 -16 -8 2 3 2 4 V(%):-:-:3:2:3:3

   Deeper images of the SGR 1900+14 field can be seen in ApJ 566, 378
(Kaplan et al. 2002).

Regards,
Taichi Kato

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