ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

Abstract

We present a Chandra observation of the supernova remnant (SNR) 3C 397 (G41.1À0.3) obtained with the Advanced CCD Imaging Spectrometer (ACIS-S). Previous studies of this SNR have shown that the remnant harbors a central X-ray ''hot spot'' suggestive of a compact object associated with 3C 397. With the Chandra data, we can rule out the nature of the hot spot as a pulsar or a pulsar wind nebula and put an upper limit on the flux of a hidden compact object of F X (0:5 10 keV ) $ 6 ; 10 À13 ergs cm À2 s À1 . We found two point sources in the observed Chandra field. We argue that neither of them is associated with 3C 397 and that the hard source, CXO J190741.2+070650, which is characterized by a heavily absorbed spectrum with a strong Fe line, is a newly discovered active galactic nucleus. The Chandra image reveals arcsecond-scale clumps and knots that are strongly correlated with the radio VLA image, except for the X-ray hot spot. Our Chandra spatially resolved spectroscopic study shows that one-component models are inadequate and that at least two nonequilibrium ionization thermal components are needed to fit the spectra of each selected region. The derived average spectral parameters are consistent with the previous global ASCA fits performed by Safi-Harb and coworkers. However, the hard component requires a high abundance of Fe indicating the presence of hot Fe ejecta. When comparing the eastern with the western lobe, we find that the column density, the brightness, and the ionization timescales are generally higher for the western side. This result, combined with our study of the 3C 397 environs at millimeter wavelengths, indicates a denser medium to the west of the SNR. Our multiwavelength imaging and spectral study favors the scenario in which 3C 397 is a $5300 year old SNR expanding in a medium with a marked density gradient and is likely to be encountering a molecular cloud on the western side. We propose that 3C 397 will evolve into a mixed-morphology SNR. Subject headingg s: ISM: individual (G41.1À0.3, 3C 397) -stars: neutron -supernova remnants -X-rays: ISM

Discriminating the Progenitor Type of Supernova Remnants With Iron K-Shell Emission

“…If 3C 397 is indeed a Type Ia remnant (as suggested by Chen et al 1999), it should be relatively old ( 3000 yr) and has evolved in a high-density interstellar medium (∼5 × 10 −24 g cm −3 ), given the comparison with our model plots. These values are consistent with the estimates of Safi-Harb et al (2005), although a CC origin was suggested in their work. The explosion type of N103B has also been a matter of controversy (e.g., van der Heyden et al 2002;Lewis et al 2003), but we favor the Ia hypothesis, based on the high maximum luminosity of its parent explosion inferred from the light echo data (Rest et al 2005), in addition to the properties of the Fe Kα emission.…”

Unveiling the spatial structure of the overionized plasma in the supernova remnant W49B

“…2). Furthermore, as in W49B, similar coaxial rings and jet‐like features are also present in the X‐ray emission in SNR 3C 397 (rings in Jiang 2009; jets in Safi‐Harb et al 2005; Jiang & Chen 2010) that is interacting with a complicated molecular environment (Jiang & Chen 2010); our simulation may also provide a similar (but qualitative) explanation for the structures in 3C 397.…”

Fe K and ejecta emission in SNR G15.9+0.2 withXMM-Newton

“…Such density variations and/or cavities are likely to be common, especially around young CC SNRs, but are hard to observe, except in the brightest and more extended sources. As another instance, Safi-Harb et al (2005) found different Fe K centroids in eastern and western regions of 3C 397, attributed to density gradients. Patnaude et al (2015) have modelled CC SNe exploding in CSM modified by progenitors' winds and followed their dynamics (i.e.…”