[ Previous | Next ]
ATEL # 1142; A. Soderberg (Caltech) and S. Immler (NASA/GSFC/U of Maryland) on behalf of the Swift satellite team
on 12 Jul 2007; 3:53 UT
Password Certification: Stefan Immler (firstname.lastname@example.org)
Subjects: Optical, Ultra-Violet, X-ray, Nova, Supernova
We observed the field of SN 2007bg (CBET #927, #948, GCN #6618) with the Swift XRT and UVOT on 2007 Apr 22.4 UT. In the 9.6 ksec observation, no X-ray source is detected coincident with the optical position to a 3-sigma limit of F_x = 4.6E-14 ergs/cm/cm/s (0.2-10 keV) and L_x = 1.2 E41 ergs/s, assuming a Galactic column density of 1.9E+20 cm-2 (Dickey & Lockman, 1990, ARAA 28, p215), a distance of 147 Mpc (z=0.034), and a 10 keV thermal spectrum. The following UVOT magnitudes and upper limits were measured: V = 18.8 (280 s exposure times), B = 19.8 (280 s), U = 20.1 (280 s), UVW1 [181-321nm] > 21.0 (3-sigma upper limit; 562 s), UVM2 [166-268 nm] > 21.6 (576 s), and UVW2 [112-264 nm] > 21.8 (1125 s). Statistical and systematic errors are 0.1 each. The magnitudes have not been corrected for extinction.
In the UVOT data, the candidate host galaxy is only detected in the UVM2 and UVW2 filters. Photometry gives the following magnitudes: V > 19.8 (3.0-sigma), B > 20.7 (3.0-sigma), U > 20.3 (3.0-sigma), UVW1 > 20.7 (3.0-sigma), UVM2 = 20.4 ± 0.3 (3.3-sigma), UVW2 = 20.7 ± 0.2 (5.2-sigma).
No further Swift observations are planned.