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 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 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 The growth of interest for astronomical X-ray polarimetry

2018 ◽  
Author(s):  
Frédéric Marin
Keyword(s):  
Quantitative Assessment ◽  
Supernova Remnant ◽  
Scientific Literature ◽  
High Energy ◽  
X Ray ◽  
Highly Sensitive ◽  
In The Beginning ◽  
First Time

Astronomical X-ray polarimetry was first explored in the end of the 60's by pioneering rocket instruments. The craze arising from the first discoveries on stellar and supernova remnant X-ray polarization led to the addition of X-ray polarimeters on-board of early satellites. Unfortunately, the inadequacy of the diffraction and scattering technologies required to measure polarization with respect to the constraints driven by X-ray mirrors and detectors, coupled to long integration times, slowed down the field for almost 40 years. Thanks to the development of new, highly sensitive, compact X-ray polarimeters in the beginning of the 2000's, the possibility to observe astronomical X-ray polarization is rising again and scientists are now ready to explore the high energy sky thanks to modern X-ray polarimeters. In the forthcoming years, several X-ray missions (both rockets, balloons and satellites) will open a new observational windows. A wind of renewal blows over the area of X-ray polarimetry and this paper presents for the first time a quantitative assessment, all based on scientific literature, of the growth of interest for astronomical X-ray polarimetry.

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 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 XMM-Newton observations of the non-thermal supernova remnant HESS J1731−347 (G353.6-0.7)

2017 ◽  
Vol 608 ◽  
pp. A23 ◽  
Author(s):  
V. Doroshenko ◽  
G. Pühlhofer ◽  
A. Bamba ◽  
F. Acero ◽  
W. W. Tian ◽  
...  
Keyword(s):  
Supernova Remnant ◽  
Galactic Plane ◽  
Thermal Power ◽  
X Rays ◽  
Absorption Column ◽  
X Ray ◽  
Spatially Resolved ◽  
Absorbing Material ◽  
First Time ◽  
X Ray Absorption

We report on the analysis of XMM-Newton observations of the non-thermal shell-type supernova remnant HESS J1731−347 (G353.6-0.7). For the first time the complete remnant shell has been covered in X-rays, which allowed direct comparison with radio and TeV observations. We carried out a spatially resolved spectral analysis of XMM-Newton data and confirmed the previously reported non-thermal power-law X-ray spectrum of the source with negligible variations of spectral index across the shell. On the other hand, the X-ray absorption column is strongly variable and correlates with the CO emission thus confirming that the absorbing material must be in the foreground and reinforcing the previously suggested lower limit on distance. Finally, we find that the X-ray emission of the remnant is suppressed towards the Galactic plane, which points to lower shock velocities in this region, likely due to the interaction of the shock with the nearby molecular cloud.

scholarly journals Broadband spectral investigations of SGR J1550–5418 bursts

2012 ◽  
Vol 8 (S291) ◽  
pp. 444-446
Author(s):  
Lin Lin ◽  
Ersin Göğüş
Keyword(s):  
Magnetic Field ◽  
Spectral Analysis ◽  
Neutron Star ◽  
Hot Spots ◽  
Gamma Ray ◽  
Gamma Ray Burst ◽  
X Ray ◽  
Surface Magnetic Field ◽  
First Time ◽  
Burst Emission

AbstractWe present the results of our broadband (0.5 − 200 keV) spectral analysis of 42 SGR J1550–5418 bursts simultaneously detected with the Swift/X-ray Telescope (XRT) and the Fermi/Gamma-ray Burst Monitor (GBM), during the 2009 January active episode of the source. We find that, on average, the burst spectra are better described with two blackbody functions than with the Comptonized model. Thus, our joint XRT/GBM analysis clearly shows for the first time that the SGR J1550–5418 burst spectra might naturally be expected to exhibit a more truly thermalized character, such as a two-blackbody or even a multi-blackbody signal. We also studied the spin phase of the XRT burst emission, which indicate that the burst emitting sites on the neutron star need not to be co-located with hot spots emitting the bulk of the persistent X-ray emission and the surface magnetic field of SGR J1550–5418 is likely non-uniform over the emission zone.

scholarly journals X-rays from the mode-switching PSR B0943+10

2017 ◽  
Vol 13 (S337) ◽  
pp. 62-65 ◽  
Author(s):  
S. Mereghetti ◽  
L. Kuiper ◽  
A. Tiengo ◽  
J. Hessels ◽  
W. Hermsen ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Thermal Emission ◽  
Mode Switching ◽  
X Rays ◽  
Radio Telescopes ◽  
Polar Cap ◽  
Radio Observations ◽  
X Ray ◽  
First Time

AbstractNew simultaneous X-ray and radio observations of the archetypal mode-switching pulsar PSR B0943+10 have been carried out with XMM-Newton and the LOFAR, LWA and Arecibo radio telescopes in November 2014. They allowed us to better constrain the X-ray spectral and variability properties of this pulsar and to detect, for the first time, the X-ray pulsations also during the X-ray-fainter mode. The combined timing and spectral analysis indicates that unpulsed non-thermal emission, likely of magnetospheric origin, and pulsed thermal emission from a small polar cap are present during both radio modes and vary in a correlated way.

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.

Sign in / Sign up

Export Citation Format

Share Document