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Swift Observations of SN 2006dm in MCG -01-60-21

ATel #852; S. Immler, Goddard Space Flight Center, NASA, and Universities Space Research Association; P. J. Brown, Pennsylvania State University, P. Milne, Steward Observatory, University of Arizona; on behalf of the Swift-satellite team
on 6 Jul 2006; 22:50 UT
Credential Certification: Stefan Immler (immler@milkyway.gsfc.nasa.gov)

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

We report on Swift Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations of SN 2006dm (cf. CBET 568, 569). The following UVOT magnitudes were measured for SN 2006dm on July 5.63 UT: V = 16.7 (421-s exposure), B = 16.8 (428 s), U = 16.4 (423 s), UVW1 [181-321 nm] = 18.3 (852 s), UVM2 [166-268 nm] > 20.5 (5-sigma upper limit; 983 s), and UVW2 [112-264 nm] = 20.1 (1,720 s). On July 6.03 UT, the SN has brightened to V = 16.6 (362 s), B = 16.7 (368 s), U = 16.2 (361 s), UVW1 = 18.1 (744 s), UVM2 = 20.6 (1,008 s), and UVW2 = 20.1 (1,555 s). Statistical and systematic errors are 0.1 mag each.

Comparisons of the UVW2-UVW1, U-B, and B-V colors show that the colors match those of the type-Ia SN 2005am shortly before maximum in the B band. The UVW1-U color is ~0.5 mag bluer than for SN 2005am which might be due to the blue continuum described by Filippenko et al. (2006, CBET 568).

No X-ray source is detected at the position of the SN in the merged 9.8 ks XRT observation for the dates given above. The 3-sigma upper limit to the XRT net count rate is 2.1 E-03 cts/s, corresponding to a (0.2-10 keV) X-ray flux and luminosity of <1.1 E-13 ergs/cm/cm/s and <1.1 E41 ergs/s, respectively, for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of N_H = 3.67E+20 (Dickey & Lockman, 1990, ARAA. 28, p215) and a distance of 94.5 Mpc (z=0.02202, NED).

Further Swift observations are scheduled.

UVOT finding chart