X-RAY EMISSION FROM THE STARBURST GALAXY IC 342
JOEL N. BREGMAN AND CAROLINE V. COX
Department of Astronomy, University of Michigan, Ann Arbor, MI 48109
AND
KOHJI TOMISAKA
Laboratory of Physics, Faculty of Education, Niigata University, Ikarashi
2-8050, Niigata 950-21, Japan
Received 1993 May 12; accepted 1993 July 16
ABSTRACT
Multiple supernovae in starburst galaxies should produce a hot gas
bubble that evolves through stages with distinctive X-ray signatures. We
obtained X-ray observations of IC 342 with the ROSAT High Resolution
Imager and find both diffuse and point source X-ray emission from the
central region with a luminosity of 1.5 x 10^39 ergs s^-1. The diffuse
emission has a diameter of 400 pc, a hot gas density of 0.2 cm^-3, and a
pressure of ~ 10^6 K cm^-3. The X-ray size and shape are similar to that
seen at 1.4 GHz and in H{alpha}, but unlike the prominent molecular bar.
Theoretical modeling implies that the hot gas bubble has an age of
2 x 10^5 yr and is still confined to the disk, suggesting that IC 342 is
a starburst galaxy early in its development. Subject headings: galaxies: individual (IC 342) --- galaxies: starburst --- X-rays: galaxies