New Transient, XTE J1730-318
ATel #113; R. A. Remillard, A. M. Levine, and E. H. Morgan (M. I.T.), E. Smith, and J. Swank (NASA GSFC)
on 14 Jan 2003; 21:05 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Ron Remillard (rr@space.mit.edu)
Subjects: X-ray, Black Hole, Transient
We report the discovery of a transient X-ray source at (J2000)
17h19m58s, -31 46'.8 (estimated 3' uncertainty at 90% confidence).
The source was first detected on 2003 January 9 when the average
flux (2-12 keV) was 130 +- 20 mCrab. The intensity increased to
430 +- 40 mCrab on Jan. 10 and 400 +- 20 mCrab on Jan. 13.
A brief observation of the ASM position on Jan. 14 with the RXTE PCA
confirms the presence of a bright transient. More extensive
observations with the PCA and HEXTE, including raster scans
to improve the source position, are planned starting Jan. 15. The
error circle does not contain any noteworthy sources in the Simbad
catalogs. The ASM hardness ratios indicate that the spectrum was
moderately hard Jan. 9-10 and relatively soft on Jan. 13. These
results resemble the early spectral evolution of X-ray transients
known to contain an accreting black hole. We encourage optical and
radio observations of this new transient.
