[vsnet-alert 14173] Optical flare of an X-ray source XMMSL1 J014956.7+533504

[Korotkiy Stas]

http://www.astronomerstelegram.org/?read=3896
Optical flare of an X-ray source XMMSL1 J014956.7+533504
ATel #3896; S. A. Korotkiy (Ka-Dar Obs.) and K. V. Sokolovsky (ASC Lebedev/SAI MSU)

A bright (unfiltered magnitude 12.8) optical flare was detected on 2012 January 29 at position 01:49:56.77 +53:35:01.8 (+/-0.5", J2000) coinciding with an X-ray source listed in the XMM-Newton slew survey catalog XMMSL1 J014956.7+533504 (Saxton et al. 2008, A&A, 480, 611), an optical object USNO-B1.0 1435-0053799 (B1mag=15.96, R1mag=14.86; Monet et al. 2003, AJ, 125, 984), and a near-infrared object 2MASS 01495682+5335017 (J=13.717 +/-0.025; H=13.341 +/-0.037; Ks=13.160 +/-0.033 Skrutskie et al. 2006, AJ, 131, 1163). Inspection of previous images of this field revealed that the object was also detected on images from January 26, 27, and 28, but not on images from January 24 and 25.

     
    Date            JD         mag. err. 
2012-01-24.6944 2455951.1944 >14.5 
2012-01-25.6990 2455952.1990 >14.5 
2012-01-26.7913 2455953.2913  14.34 0.13 
2012-01-27.7485 2455954.2485  13.73 0.08 
2012-01-28.6859 2455955.1859  13.22 0.05 
2012-01-29.7041 2455956.2041  12.80 0.03 
Visual inspection reveals that the object is also visible on some of our archival images but is below the detection limit of our system (~14.5m), its brightness at these epochs is consistent with the one listed in the USNO-B1.0 catalog.

The observations were obtained with a wide-field survey camera (F=135mm f/2.0 telephoto lens equipped with ST8300M CCD) operated by Ka-Dar Observatory at Karachay-Cherkessia (MPC code C32), Russia. The instrumental magnitude scale is calibrated using V magnitudes of Tycho-2 (Hog et al., 2000, A&A, 355L, 27) stars in the field of view.

Follow-up observations are needed to determine the nature of this flaring object.