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A New X-ray Transient: XTE J1652-453

ATel #2107; C. B. Markwardt (U. Maryland and NASA/GSFC), J. H. Swank (NASA/GSFC), H. A. Krimm (USRA and NASA/GSFC), D. Pereira (Wyle IS and NASA/GSFC), T. E. Strohmayer (NASA/GSFC)
on 3 Jul 2009; 00:00 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Craig B. Markwardt (craigm@lheamail.gsfc.nasa.gov)

Subjects: X-ray, Request for Observations, Binary, Black Hole, Neutron Star, Transient

Referred to by ATel #: 2108, 2120, 2125, 2135, 2190, 2219

We report the discovery of a new X-ray transient, XTE J1652-453. In two RXTE PCA monitoring scans of the galactic ridge region on 2009-06-28 and 2009-07-01, a new point source was detected. A position fit to the scan light curves gives a position, R.A. = 253.192, Dec. = -45.353, with formal 95% uncertainties of about 2 arcminutes.

The 2-10 keV fluxes are 37 and 112 mCrab on the two respective scan dates, suggesting a quickly rising flux. A pointed RXTE PCA observation on 2009-07-02 at 14:20 UTC detected the source at a flux of about 110 mCrab. The fluxes in the 2-10, 10-20 and 20-40 keV bands were: 264, 6, 6, in units of 1e-11 erg/cm^2/s.

The spectrum is consistent with a black body (kT ~ 0.6 keV) and power law (index 1.99), with an line feature at 6.4 keV (eq width 180 eV). About 90% of the flux is in the black body component. There are no significant timing features in the power spectrum.

Swift BAT detects a source at a position consistent with the XTE source, at a flux of about 10 mCrab (15-150 keV), starting around 2009-06-27.

The energy spectrum suggests a black hole candidate in a spectral "high" state, which would be consistent with the lack of X-ray variability.

Additional RXTE and Swift observations are anticipated.