Continued Swift/XRT Follow-up of the Fermi-LAT Galactic Plane Transient J0902-4624
ATel #3992; C. C. Cheung (NRC/NRL), D. Donato, E. Hays, R. Ojha (NASA/GSFC), on behalf of the Fermi-LAT collaboration
on 21 Mar 2012; 18:52 UT
Credential Certification: Teddy Cheung (ccheung@milkyway.gsfc.nasa.gov)
Subjects: X-ray, Gamma Ray, >GeV, Transient
Following the Fermi-LAT detection of the Galactic Plane gamma-ray transient J0902-4624 (l, b = 267.47 deg, 0.07 deg) on 15 March 2012 (ATEL #3972), we reported the detection of four X-ray sources within the LAT 68% confidence error circle in an initial Swift 9.9 ks follow-up observation on 17 March (ATEL #3973).
We carried out two subsequent 5 ks Swift observations on 19 March (05:17 - 11:05 UT) and 21 March (01:35 - 08:22 UT), and now find that the brightest source (XRT1) faded by a factor of ~2 since the first observation, while in the third observation, XRT2 and XRT3 brightened by factors of ~2 and ~3, respectively. The fourth source (XRT4, 2.7 sigma in the initial observation) lies at the edge of the XRT field and was not confirmed in the subsequent observations. Tabulated below are the X-ray source positions for the three sources (from ATEL #3973) along with their 0.3-10 keV count rates (and errors) at the three epochs.
Observations of these variable X-ray sources at other wavelengths is encouraged to reveal their nature.
We thank the Swift team for their rapid scheduling of the observations.
source# RA(J2000) Dec(J2000) Epoch1 Epoch2 Epoch3
XRT1 09:02:05.90 -46:22:48.49 4.57(0.81)e-3 2.20(0.84)e-3 1.91(0.75)e-3
XRT2 09:02:13.37 -46:30:36.10 2.04(0.57)e-3 0.33(0.39)e-3 4.18(1.09)e-3
XRT3 09:02:45.99 -46:17:53.36 2.60(0.67)e-3 2.17(0.84)e-3 7.83(1.55)e-3
