scholarly journals X-ray emission from the mixed-morphology supernova remnant HB 9

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Mariko Saito ◽  
Shigeo Yamauchi ◽  
Kumiko K Nobukawa ◽  
Aya Bamba ◽  
Thomas G Pannuti
Keyword(s):  
Spectral Analysis ◽  
Central Region ◽  
Supernova Remnant ◽  
Interstellar Matter ◽  
Plasma Model ◽  
Ionization Equilibrium ◽  
Equilibrium Plasma ◽  
X Ray ◽  
Collisional Ionization ◽  
Matter Component

Abstract We present the results of a spectral analysis of the central region of the mixed-morphology supernova remnant HB 9. A prior Ginga observation of this source detected a hard X-ray component above 4 keV, and the origin of this particular X-ray component is still unknown. Our results demonstrate that the extracted X-ray spectra are best represented by a model consisting of a collisional ionization equilibrium plasma with a temperature of ∼0.1–0.2 keV (interstellar matter component) and an ionizing plasma with a temperature of ∼0.6–0.7 keV and an ionization timescale of >1 × 1011 cm−3 s (ejecta component). No significant X-ray emission was found in the central region above 4 keV. The recombining plasma model reported by a previous work does not explain our spectra.

scholarly journals Discovery of recombining plasma associated with the candidate supernova remnant G189.6+3.3 with Suzaku

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Shigeo Yamauchi ◽  
Moe Oya ◽  
Kumiko K Nobukawa ◽  
Thomas G Pannuti
Keyword(s):  
Spectral Analysis ◽  
Supernova Remnant ◽  
Spectral Feature ◽  
Plasma Component ◽  
Ionization Equilibrium ◽  
Equilibrium Plasma ◽  
Northeast Region ◽  
X Ray ◽  
Collisional Ionization ◽  
First Time

Abstract We present the results of an X-ray spectral analysis of the northeast region of the candidate supernova remnant G189.6+3.3 with Suzaku. K-shell lines from highly ionized Ne, Mg, Si, and S were detected in the spectrum for the first time. In addition, a radiative recombining continuum (RRC) from He-like Si was clearly seen near 2.5 keV. This detection of an RRC reveals for the first time that G189.6+3.3 possesses an X-ray-emitting recombining plasma (RP). The extracted X-ray spectrum in the 0.6–10.0 keV energy band is well fitted with a model consisting of a collisional ionization equilibrium plasma component (associated with the interstellar medium) and an RP component (associated with the ejecta). The spectral feature shows that G189.6+3.3 is most likely to be a middle-aged SNR with an RP.

scholarly journals Discovery of recombining plasma inside the extended gamma-ray supernova remnant HB9

2019 ◽  
Vol 489 (3) ◽  
pp. 4300-4310 ◽  
Author(s):  
A Sezer ◽  
T Ergin ◽  
R Yamazaki ◽  
H Sano ◽  
Y Fukui
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Large Area ◽  
Imaging Spectrometer ◽  
X Ray ◽  
East Region ◽  
X Ray Imaging ◽  
Collisional Ionization

ABSTRACT We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the other hand, the X-ray spectra from the eastern Suzaku observation region are best reproduced by the CIE and non-equilibrium ionization model. We discuss possible scenarios to explain the origin of the RP emission based on the observational properties and concluded that the rarefaction scenario is a possible explanation for the existence of RP. In addition, the gamma-ray emission morphology and spectrum within the energy range of 0.2–300 GeV are investigated using 10 yr of data from the Fermi Large Area Telescope (LAT). The gamma-ray morphology of HB9 is best described by the spatial template of radio continuum emission. The spectrum is well fit to a log-parabola function and its detection significance was found to be 25σ. Moreover, a new gamma-ray point source located just outside the south-east region of the SNR’s shell was detected with a significance of 6σ. We also investigated the archival H i and CO data and detected an expanding shell structure in the velocity range of $-10.5$ and $+1.8$ km s−1 that is coinciding with a region of gamma-ray enhancement at the southern rim of the HB9 shell.

scholarly journals An X-ray characterization of the central region of the supernova remnant G332.5-5.6

2015 ◽  
Vol 583 ◽  
pp. A84 ◽  
Author(s):  
A. E. Suárez ◽  
J. A. Combi ◽  
J. F. Albacete-Colombo ◽  
S. Paron ◽  
F. García ◽  
...  
Keyword(s):  
Central Region ◽  
Supernova Remnant ◽  
X Ray

scholarly journals Evolution and State of the Local ISM

1996 ◽  
Vol 171 ◽  
pp. 442-442
Author(s):  
T. Schmutzler ◽  
D. Breitschwerdt
Keyword(s):  
Basic Feature ◽  
Emission Lines ◽  
Continuum Emission ◽  
Ionization Equilibrium ◽  
X Ray ◽  
Self Consistent ◽  
X Ray Background ◽  
Collisional Ionization ◽  
Consistent Approach ◽  
The Continuum

The most puzzling observations concerning the LISM (distance < 100 pc) can be explained by a fast adiabatically cooled gas in the cavity of an old superbubble. The ultrasoft X-ray background and contributions to the C- and M-bands are due to the continuum emission of delayed recombination [1]. In contrast to collisional ionization equilibrium (CIE) models, but consistent with recent observations [2], our model predicts a lack of emission lines and a low emissivity in the EUV range. In the figure below we compare the emissivities resulting from CIE at T = 106 K and those from our model at T = 4.2 × 104 K. The basic feature of our model is a thermally self-consistent approach of the time-dependent evolution.

scholarly journals Characterization of diffuse X-ray emission from IGR J17448$-$3232: an implication of a line-of-sight merging activity

2019 ◽  
Author(s):  
Shoko Watanabe ◽  
Shigeo Yamauchi ◽  
Kumiko K Nobukawa ◽  
Hiroki Akamatsu
Keyword(s):  
Electron Temperature ◽  
Central Region ◽  
Intensity Ratio ◽  
Spectral Feature ◽  
Line Of Sight ◽  
High Electron ◽  
Plasma Model ◽  
Ionization Equilibrium ◽  
Temperature Plasma ◽  
Two Component

Abstract The results of spectral analysis for the galaxy cluster IGR J17448$-$3232 are presented. The intracluster medium (ICM) in the central region ($r\lt 300^{\prime \prime }$, $320\:$kpc) has a high electron temperature plasma of $kT_{\rm e} \sim 13$–$15\:$keV, and an ionization temperature estimated from an intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines is lower than the electron temperature, which suggests that the ICM is in the non-ionization equilibrium (NEI) state. The spectrum in the central region can be also fitted with a two-component model: a two-temperature plasma model in a collisional ionization equilibrium (CIE) with temperatures of $7.9\:$keV and $\gt 34\:$keV, or a CIE$+$power-law model with a temperature of $9.4\:$keV and a photon index of 1.1. The two-component models can represent the intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines. On the other hand, the spectrum in the outer region ($r\gt 300^{\prime \prime }$) can be explained by a single CIE plasma model with a temperature of 5–$8\:$keV. Based on the spectral feature and its circular structure, we propose that the NEI plasma was produced by merging along the line-of-sight direction.

scholarly journals X-Ray Spectroscopic Measurements of Non-Equilibrium Ionization in Supernova Remnants

1984 ◽  
Vol 86 ◽  
pp. 76-79
Author(s):  
T.H. Markert ◽  
C.R. Canizares ◽  
T. Pfafman ◽  
P. Vedder ◽  
P.F. Winkler ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
X Rays ◽  
Ionization Equilibrium ◽  
X Ray ◽  
Elemental Abundances ◽  
Ion Collisions ◽  
Ionization Structure ◽  
Cool Plasma ◽  
Collisional Ionization ◽  
Time Required

When a cool plasma is shock-heated to X-ray temperatures, the ionization structure does not attain its final, equilibrium value immmediately, but proceeds toward it through electron-ion collisions with a timescale τ ≡ net of order 1012 cm−3 sec. For supernova remnants (SNRs), where 0.1 ≤ ne ≤ 10 cm−3 typically, the time required to achieve collisional ionization equilibrium (CIE) can be greater than the age of the remnant. Even if the SNR is quite old, that part of the remnant which is emitting most of the X-rays may have been shocked relatively recently, so that the assumption of CIE may be inappropriate (see below).The question of ionization equilibrium is of great astrophysical importance in the study of SNRs because it affects the deduced values of their masses and elemental abundances (e.g. Shull 1982). Mass determinations are affected because underionized plasma generally has a much higher emissivity in soft X-rays than equilibrium plasma. Unless this is accounted for, the deduced value of the density and therefore of the mass, will be considerably overestimated.

scholarly journals Probing the effects of hadronic acceleration at the SN 1006 shock front

2013 ◽  
Vol 9 (S296) ◽  
pp. 315-319
Author(s):  
Marco Miceli ◽  
F. Bocchino ◽  
A. Decourchelle ◽  
G. Maurin ◽  
J. Vink ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Spectral Analysis ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Ambient Medium ◽  
Cosmic Ray ◽  
X Ray ◽  
Spatially Resolved ◽  
Large Program ◽  
Post Shock

AbstractSupernova remnant shocks are strong candidates for being the source of energetic cosmic rays and hadron acceleration is expected to increase the shock compression ratio, providing higher post-shock densities. We exploited the deep observations of the XMM-Newton Large Program on SN 1006 to verify this prediction. Spatially resolved spectral analysis led us to detect X-ray emission from the shocked ambient medium in SN 1006 and to find that its density significantly increases in regions where particle acceleration is efficient. Our results provide evidence for the effects of acceleration of cosmic ray hadrons on the post-shock plasma in supernova remnants.

scholarly journals X-ray Emission from G359.1-0.5

1997 ◽  
Vol 166 ◽  
pp. 417-420
Author(s):  
Roland Egger ◽  
Xuejun Sun
Keyword(s):  
Thermal Plasma ◽  
Large Distance ◽  
Supernova Remnant ◽  
Radio Observation ◽  
Plasma Model ◽  
Diffuse Emission ◽  
X Ray ◽  
Pointed Observation

AbstractWe report on the detection of X-ray emission from the supernova remnant (SNR) G359.1-0.5 in a deep ROSAT PSPC pointed observation. The diffuse emission is well confined within the radio shell of the SNR. Its spectrum can be represented by a thermal plasma model at T ~ 1 keV and Fx ~ 2×10−11 erg cm−2 s−1 (0.1–2.0 keV) modified by the column absorption of NH ~ 3 × 1022 cm−2. This result supports the view that the source is at a large distance consistent with that from radio observation, and helps to resolve a puzzle about the SNR in previous observations.

scholarly journals X-ray study of spatial structures in Tycho’s supernova remnant using unsupervised deep learning

2019 ◽  
Vol 488 (3) ◽  
pp. 4106-4116 ◽  
Author(s):  
Hiroyoshi Iwasaki ◽  
Yuto Ichinohe ◽  
Yasunobu Uchiyama
Keyword(s):  
Spectral Analysis ◽  
Deep Learning ◽  
Spectral Data ◽  
Supernova Remnant ◽  
Rapid Development ◽  
Feature Space ◽  
Gaussian Mixture ◽  
Spatial Structures ◽  
X Ray ◽  
Unsupervised Deep Learning

ABSTRACT Recent rapid development of deep learning algorithms, which can implicitly capture structures in high-dimensional data, opens a new chapter in astronomical data analysis. We report here a new implementation of deep learning techniques for X-ray analysis. We apply a variational autoencoder (VAE) using a deep neural network for spatio-spectral analysis of data obtained by Chandra X-ray Observatory from Tycho’s supernova remnant (SNR). We established an unsupervised learning method combining the VAE and a Gaussian mixture model (GMM), where the dimensions of the observed spectral data are reduced by the VAE, and clustering in feature space is performed by the GMM. We found that some characteristic spatial structures, such as the iron knot on the eastern rim, can be automatically recognized by this method, which uses only spectral properties. This result shows that unsupervised machine learning can be useful for extracting characteristic spatial structures from spectral information in observational data (without detailed spectral analysis), which would reduce human-intensive preprocessing costs for understanding fine structures in diffuse astronomical objects, e.g. SNRs or galaxy clusters. Such data-driven analysis can be used to select regions from which to extract spectra for detailed analysis and help us make the best use of the large amount of spectral data available currently and arriving in the coming decades.

scholarly journals ROSAT X-Ray Observations of the Radio Galaxy 4C46.09

1998 ◽  
Vol 188 ◽  
pp. 447-448
Author(s):  
D.A. Leahy
Keyword(s):  
Spectral Analysis ◽  
Radio Source ◽  
Supernova Remnant ◽  
Radio Galaxy ◽  
High Energy ◽  
Energy Component ◽  
X Ray ◽  
Hardness Ratio ◽  
High Energy Component

4C46.09 is the radio source that shows up as a point-like x-ray source inside the supernova remnant HB9 (Leahy, 1987). Leahy, 1987 found a 0.2-4 keV Einstein IPC flux of approximately 1.5 × 10−12erg cm−2s−1 and a significantly higher hardness ratio than the rest of HB9. Too few counts were available for any spectral analysis. Seward et al, 1991, found 4C46.09 to be a large radio galaxy at redshift 0.195 and distance 1280 Mpc (Ho = 50 km s−1Mpc−1). 4C46.09 is of further interest due to the observation of a high energy component in the spectrum of HB9 observed by GINGA (Yamauchi and Koyama, 1993). Whether this was due to HB9 or to 4C46.09 could not be determined.

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