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Chandra Observations of SNe 2011dh and 2011by

ATel #3456; D. Pooley (Eureka Scientific) on behalf of a larger collaboration
on 28 Jun 2011; 05:08 UT
Credential Certification: dave pooley (dave@mit.edu)

Subjects: X-ray, Supernovae

As part of our ongoing program to investigate X-ray emission from supernovae with Chandra, we triggered 10-ksec Chandra ToO observations of the Type IIb supernova 2011dh (ATel #3398, CBET #2736) and the Type Ia SN 2011by (CBET #2708).

We confirm that the X-ray emission detected with Swift/XRT (ATel #3400, #3414) in the direction of SN 2011dh is from the supernova. Our Chandra observation, which began 2011-Jun-12.3, detected ~115 counts from the supernova. Preliminary spectral fits assuming only Galactic absorption of N_H = 1.8e20 cm^-2 indicate a relatively normal spectrum with power law index of 1.4 +/- 0.3 (1 sigma) and an unabsorbed X-ray flux of (1.0 +/- 0.3) x 10^-13 erg/cm^2/s [0.5-8 keV]. This is a softer spectrum and a lower flux than reported in ATel #3414, indicating some evolution of the source on a timescale of roughly a week. There do not appear to be any other X-ray sources within 45" of the supernova in our Chandra data.

The X-ray emission detected with Swift/XRT in the direction of SN 2011by (ATel #3410) is not from the supernova, but rather a nearby source about 2.3" away. Our Chandra observation, which began 2011-Jun-22.7, finds no other source present within 20" of the position of the supernova, and one additional source between 20" and 45". Preliminary spectral fits indicate a flux of (1.2 +/- 0.4) x 10^-14 erg/cm^2/s [0.5-8 keV] for the nearby source, consistent with the flux reported in ATel #3410.