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ATEL # 1017; S. Immler (NASA/USRA/GSFC), P. J. Brown (PSU), and P. Milne (U of Arizona) on behalf of the Swift satellite team
on 1 Mar 2007; 16:02 UT
Password Certification: Stefan Immler (firstname.lastname@example.org)
Subjects: Optical, Ultra-Violet, X-ray
Swift Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) observed the type II SN 2007aa (CBET #850, IAUC # 8814 ) on 2007-02-24.63 UT. The following UVOT magnitudes were measured: V = 15.8 (322 s exposure time), B = 16.4 (367 s), U = 16.9 (367 s), UVW1 [181-321nm] = 18.6 (737 s), UVM2 [166-268 nm] > 19.5 (3-sigma upper limit; 236 s), and UVW2 [112-264 nm] = 19.7 (725 s). The magnitudes have not been corrected for extinction. Statistical and systematic errors are estimated to be 0.1 mag each.
No X-ray source is detected at the position of the SN in the 3.4 ks Swift XRT observation obtained simultaneously with the UVOT observations. The 3-sigma upper limit to the XRT net count rate is 2.9 E-03 cts/s, corresponding to an unabsorbed (0.2-10 keV band) X-ray flux of <1.4 E-13 ergs/cm/cm/s and a luminosity of <7.2 E39 ergs/s for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of N_H = 2.22E+20 (Dickey & Lockman, 1990, ARAA 28) and a distance of 20.7 Mpc (z=0.004887, NED; H_o = 71 km/s/Mpc, Omega_M = 1/3, Omega_L = 2/3).