Swift Observations of GRB 150907A

J.A. Kennea (PSU) and M. De Pasquale (UCL-MSSL) for the Swift team

1. Introduction

Nakagawa et al. (GCN Circ. 18246) reported the GRB detection. The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 16:00:50 UT on 7 September 2015. Table 1 contains the best reported positions from Swift.

Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.

2. BAT Observations and Analysis

BAT did not observe this burst.

3. XRT Observations and Analysis

XRT results are not available.

4. UVOT Observations and Analysis

The Swift/UVOT began settled observations (De Pasquale and Malesani GCN Circ. 18255) of the field of GRB 150907A 8821 s after the MAXI trigger (Suzuki et al., GCN Circ. 18246). Table 3 gives preliminary magnitudes using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc., 1358, 373). No correction has been made for the expected extinction in the Milky Way corresponding to a reddening of E_B-V of 0.08 mag. in the direction of the GRB (Schlegel et al. 1998).

Figure 1. The BAT light curve is not available.

RA (J2000)	Dec (J2000)	Error	Note	Reference
15h00m12.68s	-47°42'28.8"	6.8"	XRT	Kennea et al. GCN Circ. 18311

Table 1. Positions from the Swift instruments.

Band	Authors	GCN Circ.	Subject	Observatory	Notes
X-ray	Nakagawa et al.	18246	MAXI/GSC detection	MAXI	detection

Table 2. Summary of GCN Circulars from other observatories sorted by band and then circular number.

Filter	Tstart(s)	Tstop(s)	Exp(s)	Mag
u	8821	18835	336	>19.5

Table 3. UVOT observation reported by De Pasquale and Malesani (GCN Circ. 18255). The start and stop time of the exposure are given in seconds since the BAT trigger. The preliminary 3-σ upper limit is given. No correction has been made for extinction in the Milky Way.

September 15, 2015