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ATEL # 1463; S. Immler (NASA/CRESST/GSFC), P. J. Brown (PSU), and P. Milne (U Arizona), on behalf of the Swift satellite team
on 7 Apr 2008; 2:52 UT
Password Certification: Stefan Immler (email@example.com)
Subjects: Optical, Ultra-Violet, X-ray, Nova, Supernova
The Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) on board the Swift satellite observed the supernova (SN) 2008bo in NGC 6643 (CBET #1324, #1325) on 2008-04-04.71 UT and 2008-04-06.31 UT. The following UVOT magnitudes were measured for the two epochs:
v = 15.9±0.1 (157 s exposure time), 16.0±0.1 (258 s),
b = 16.7±0.1 (157 s), 16.6±0.1 (258 s),
u = 16.6±0.1 (157 s), 16.6±0.1 (258 s),
uvw1 [181-321nm] = 17.1±0.1 (314 s), 17.2±0.1 (518 s),
uvm2 [166-268nm] = 17.3±0.1 (491 s), 17.4±0.1 (796 s), and
uvw2 [112-264 nm] = 17.3±0.1 (629 s), 17.3±0.1 (1,038 s).
These magnitudes are on the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) which in the optical is close to the Johnson UBV. The magnitudes have not been corrected for extinction. We note that a fraction of the UV emission of SN 2008bo could be due to enhanced star formation activity in the host galaxy which has a very patchy appearance in the UV. In the absence of UVOT template images of the host galaxy, the above magnitudes should therefore be regarded as tentative.
No X-ray source is detected at the position of the SN in the merged 5.2 ks Swift XRT observation obtained simultaneously with the UVOT observations. The 3-sigma upper limit to the XRT net count rate is 3.9E-03 cts/s, corresponding to an unabsorbed (0.2-10 keV band) X-ray flux of <2.2E-13 erg/cm/cm/s and a luminosity of <1.2E40 erg/s for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of N_H = 5.45E+20 (Dickey & Lockman, 1990, ARAA, 28, 215) and a distance of 21 Mpc (z=0.004950, NED; H_o = 71 km/s/Mpc, Omega_M = 1/3, Omega_L = 2/3).