2007/07/18 by E. Lenz, E. M. Schlegel · 1 citation
Physics and Astronomy · #Astrophysical Phenomena and Observations #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/521983
published as Astron.J.134:1821-1826,2007 · accepted AJ
arxiv created 2007/07/18 · openalex publication_date 2007/09/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We describe the results of a 2003 Chandra ACIS-I observation of SN 1978K. The spectrum shows little flux below 0.6 keV, in contrast to the 2002 Chandra ACIS-S observation, which showed flux to 0.4 keV. Fitting the ACIS-I spectrum alone leads to two solutions depending on the value of the column density. A joint fit using a dual thermal plasma model applied to the ACIS-I and a contemporaneous XMM-Newton spectrum, which if fit alone also leads to a two-column solution, yields a single column density fit. The fitted temperature of the joint fit for the soft component remains constant within the errors from previous Chandra , XMM-Newton , and ASCA data. The hard temperature recovers from its 2000-2002 decline and corresponds to an increase in the column density during that time. The hard (2-10 keV) light curve is confirmed to be declining. The derived number density represents a lower limit of ∼10 5 depending on the adopted filling factor of the emitting volume, leading to an estimated mass cooling rate of ∼0.1-0.15 M ⊙ yr -1 .