Swift discovers a probable new transient

ATel #1279; K. L. Page (U. Leicester), J. Tueller (GSFC) and A. P. Beardmore (U. Leicester), on behalf of the Swift team
on 14 Nov 2007; 19:17 UT
Credential Certification: Kim Page (kpa@star.le.ac.uk)

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Swift-BAT has detected a probable new galactic transient at a position of RA, Dec (J2000) = 81.4034, 24.2607 (estimated error radius of 5 arcmin) at the 6-sigma level. Two Swift-XRT observations were performed in 2007 October, totalling 9.3 ks, and a clear X-ray source was detected. This source, which is designated SWIFT J052522.48+241331.8, is located at

RA, Dec (J2000): 81.3436, 24.2255
RA, Dec (J2000): 05h 25m 22s.48, 24d 13m 31s.8

with an error radius of 4.0 arcsec (90% containment).

The XRT spectrum can be fitted by an absorbed power-law of Gamma = 1.07 +0.13/-0.06, with NH = (1.5 +/- 0.5)x10^21 cm^-2. The mean count rate is 0.120 +/- 0.004 count s^-1, with an observed (unabsorbed) flux of 1.02x10^-11 (1.37x10^-11) erg cm^-2 s^-1 over 0.3-10 keV. There is no sign of variation in count-rate between the X-ray observations on 2007-10-12 and 2007-10-18.

This source may have a 17th magnitude optical counterpart (USNO-A2.0 1125-02389994), which is also a 14th magnitude 2MASS source (2MASS J05252270+2413332).