TWO DISTINCT-ABSORPTION X-RAY COMPONENTS FROM TYPE IIn SUPERNOVAE: EVIDENCE FOR ASPHERICITY IN THE CIRCUMSTELLAR MEDIUM
Year: 2016
Type: article
Abstract: ABSTRACT We present multi-epoch X-ray spectral observations of three Type IIn supernovae (SNe), SN 2005kd, SN 2006jd, and SN 2010jl, acquired with Chandra, XMM-Newton, Suzaku, and Swift. Previous extensive X-ray studies of SN 2010jl have revealed that X-ray spectra are dominated by thermal emission, which likely arises from a hot plasma heated by a forward shock propagating into a massive circumstellar medium (CSM). Interestingly, an additional soft X-ray component was required to reproduce the spectra at a period of ∼1–2 years after the SN explosion. Although this component is likely associated with the SN, its origin remained an open question. We find a similar, additional soft X-ray component from the other two SNe IIn as well. Given this finding, we present a new interpretation for the origin of this component; it is thermal emission from a forward shock essentially identical to the hard X-ray component, but directly reaches us from a void of the dense CSM. Namely, the hard and soft components are responsible for the heavily and moderately absorbed components, respectively. The co-existence of the two components with distinct absorptions as well as the delayed emergence of the moderately absorbed X-ray component could be evidence for asphericity of the CSM. We show that the X-ray spectral evolution can be qualitatively explained by considering a torus-like geometry for the dense CSM. Based on our X-ray spectral analyses, we estimate the radius of the torus-like CSM to be on the order of ∼5 × 1016 cm.
Source: The Astrophysical Journal
Authors: Satoru Katsuda, Keiichi Maeda, Aya Bamba, Yukikatsu Terada, Yasushi Fukazawa, Koji Kawabata, Masanori Ohno, Yasuharu Sugawara, Yohko Tsuboi, Stefan Immler
Institutions: Chuo University, Kavli Institute for the Physics and Mathematics of the Universe, Kyoto University, The University of Tokyo, Research Center for the Early Universe, Saitama University, Hiroshima University, Hiroshima Astrophysical Science Center, Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Goddard Space Flight Center, University of Maryland, College Park
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: From accelerated particles to cosmic rays --- Understanding particle acceleration and escape with New-generation X-ray/gamma-ray observatories, Probing the relation between progenitors and maximum brightness for Type Ia supernovae through X-ray and optical observations of supernova remnants, Theoretical and observational multi-frequency study of supernovae: Solving open questions in stellar physics and developing applications to cosmology, Stellar wind measurements for Colliding Wind Binaries using X-ray spectra
OpenAlex ID: W2526963599