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Swift Observations/Phototyping of Probable Type II SN 2008aw

ATel #1407; P. J. Brown (PSU), S. Immler (NASA/CRESST/GSFC), and P. Milne (Steward Observatory) on behalf of the Swift satellite team
on 3 Mar 2008; 23:04 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Peter J. Brown (pbrown@astro.psu.edu)

Subjects: Optical, Ultra-Violet, X-ray, Supernovae

Swift Ultraviolet/Optical Telescope (UVOT) observed SN 2008aw (CBET # 1279 ) on 2008-03-03.65 UT. The following UVOT magnitudes were measured: v = 16.0 (211 s exposure time), b = 16.0 (211 s), u = 14.9 (211 s), uvw1 [181-321nm] = 14.9 (629 s), uvm2 [166-268 nm] = 14.9 (611 s), and uvw2 [112-264 nm] = 14.9 (1259 s). Errors are about 0.1 mag. These magnitudes are on the UVOT photometric system (Poole et al. 2008) which in the optical is close to the Johnson UBV. The magnitudes have not been corrected for extinction. The blue UV-optical colors strongly suggest the SN is a young type II (cf. Brown et al. 2007) similar to SNe 2005cs and 2006bp at about one week after explosion (Dessart et al. 2008).

No X-ray source is detected at the position of the SN in the 3.0 ks Swift XRT observation obtained simultaneously with the UVOT observations. The 3-sigma upper limit to the XRT net count rate is 3.1 E-03 cts/s, corresponding to an unabsorbed (0.2-10 keV band) X-ray flux of <1.6 E-13 erg/cm/cm/s and a luminosity of <3.7E40 erg/s for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of N_H = 1.36E+20 (Dickey & Lockman 1990) and a distance of 44 Mpc (z=0.010374, NED; H_o = 71 km/s/Mpc, Omega_M = 1/3, Omega_L = 2/3).

P. J. Brown, P. W. A. Roming, D. E. Vanden Berk, S. T. Holland, S. Immler, & P. Milne, 2007, in SUPERNOVA 1987A: 20 YEARS AFTER: Supernovae and Gamma-Ray Bursters. AIP Conference Proceedings, 937, 386 (arXiv:0802.3465)
Dessart, L., et al., 2008, ApJ, accepted (arXiv:0711.1815)
Dickey, J. M. & Lockman, F. J., 1990, ARA&A, 28, 215
Poole, T. S., et al., 2008, MNRAS, 383, 627

Swift Supernova Website