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Swift Observations of SN 2008cg

ATEL # 1598; S. Immler (NASA/CRESST/GSFC), A. V. Filippenko (UC Berkeley), and D. Pooley (U Wisconsin), on behalf of the Swift satellite team
on 2 Jul 2008; 18:42 UT
Password Certification: Stefan Immler (immler@milkyway.gsfc.nasa.gov)

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 Type IIn supernova 2008cg (CBET #1366, #1420, ATel #1594) on 2008-07-02.00 UT. The following UVOT magnitudes were measured: v = 17.90.1 (567 s exposure time), b = 18.70.1 (567 s), u = 18.90.1 (567 s), uvw1 [181-321nm] = 19.50.1 (1134 s), uvm2 [166-268nm] = 20.30.2 (1693 s), uvw2 [112-264 nm] = 20.40.1 (2270 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.

No X-ray source is detected at the position of the SN in the 7.1 ks Swift XRT observation obtained simultaneously with the UVOT observations. The 3-sigma upper limit to the XRT net count rate is 1.9E-03 cts/s, corresponding to an unabsorbed (0.2-10 keV band) X-ray flux of <1.0E-13 erg/cm/cm/s and a luminosity of <2.7E41 erg/s for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of N_H = 3.64E+20 (Dickey & Lockman, 1990, ARAA, 28, 215) and a distance of 150 Mpc (z=0.036, Giovanelli et al. 1997, AJ 114, 122, from NED; H_o = 71 km/s/Mpc, Omega_M = 1/3, Omega_L = 2/3).


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