Search results for "X-rays: ISM"
showing 10 items of 58 documents
Detection of X-ray flares from AX J1714.1-3912, the unidentified source near RX J1713.7-3946
2018
Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1-3912, near the SNR RX J1713.7-3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the ~4.5 yr time separation between the two observatio…
XMM-Newton observation of the supernova remnant Kes 78 (G32.8-0.1): Evidence for shock-cloud interaction
2017
The Galactic supernova remnant Kes 78 is surrounded by dense molecular clouds, whose projected position overlaps with the extended HESS gamma-ray source HESS J1852-000. The X-ray emission from the remnant has been recently revealed by Suzaku observations, which have shown indications for a hard X-ray component in the spectra, possibly associated with synchrotron radiation. We aim at describing the spatial distribution of the physical properties of the X-ray emitting plasma and at revealing the effects of the interaction of the remnant with the inhomogeneous ambient medium. We also aim at investigating the origin of the gamma-ray emission, which may be Inverse Compton radiation associated wi…
X-ray emission from stellar jets by collision against high-density molecular clouds: an application to HH 248
2015
We investigate the plausibility of detecting X-ray emission from a stellar jet that impacts against a dense molecular cloud. This scenario may be usual for classical T Tauri stars with jets in dense star-forming complexes. We first model the impact of a jet against a dense cloud by 2D axisymmetric hydrodynamic simulations, exploring different configurations of the ambient environment. Then, we compare our results with XMM-Newton observations of the Herbig-Haro object HH 248, where extended X-ray emission aligned with the optical knots is detected at the edge of the nearby IC 434 cloud. Our simulations show that a jet can produce plasma with temperatures up to 10 MK, consistent with producti…
Formation of X-ray emitting stationary shocks in magnetized protostellar jets
2016
X-ray observations of protostellar jets show evidence of strong shocks heating the plasma up to temperatures of a few million degrees. In some cases, the shocked features appear to be stationary. They are interpreted as shock diamonds. We aim at investigating the physics that guides the formation of X-ray emitting stationary shocks in protostellar jets, the role of the magnetic field in determining the location, stability, and detectability in X-rays of these shocks, and the physical properties of the shocked plasma. We performed a set of 2.5-dimensional magnetohydrodynamic numerical simulations modelling supersonic jets ramming into a magnetized medium and explored different configurations…
Modeling the shock-cloud interaction in SN 1006: unveiling the origin of nonthermal X-ray and gamma-ray emission
2016
The supernova remnant SN 1006 is a source of high-energy particles and its southwestern limb is interacting with a dense ambient cloud, thus being a promising region for gamma-ray hadronic emission. We aim at describing the physics and the nonthermal emission associated with the shock-cloud interaction to derive the physical parameters of the cloud (poorly constrained by the data analysis), to ascertain the origin of the observed spatial variations in the spectral properties of the X-ray synchrotron emission, and to predict spectral and morphological features of the resulting gamma-ray emission. We performed 3-D magnetohydrodynamic simulations modeling the evolution of SN 1006 and its inter…
Thermal emission, shock modification, and X-ray emitting ejecta in SN 1006
2009
Efficient particle acceleration can modify the structure of supernova remnants. In this context we present the results of the combined analysis of the XMM-Newton EPIC archive observations of SN 1006. We aim at describing the spatial distribution of the physical and chemical properties of the X-ray emitting plasma at the shock front. We investigate the contribution of thermal and non-thermal emission to the X-ray spectrum at the rim of the remnant to study how the acceleration processes affect the X-ray emitting plasma. We perform a spatially resolved spectral analysis on a set of regions covering the whole rim of the shell and we exploit the results of the spectral analysis to produce a cou…
X-ray emitting structures in the Vela SNR: ejecta anisotropies and progenitor stellar wind residuals
2021
The Vela supernova remnant (SNR) shows several ejecta fragments protruding beyond the forward shock (shrapnel). Recent studies have revealed high Si abundance in two shrapnel (A and G), located in opposite directions with respect to the SNR center. This suggests the possible existence of a Si-rich jet-counterjet structure. We analyzed an XMM-Newton observation of a bright clump, behind shrapnel G, which lies along the direction connecting A and G. The aim is to study the physical and chemical properties of this clump to ascertain whether it is part of this putative jet-like structure. We produced background-corrected and adaptively-smoothed count-rate images and median photon energy maps, a…
The shape of the cutoff in the synchrotron emission of SN 1006 observed with XMM-Newton
2013
Synchrotron X-ray emission from the rims of young supernova remnants allows us to study the high-energy tail of the electrons accelerated at the shock front. The analysis of X-ray spectra can provide information on the physical mechanisms that limit the energy achieved by the electrons in the acceleration process. We aim at verifying whether the maximum electron energy in SN 1006 is limited by synchrotron losses and at obtaining information on the shape of the cutoff in the X-ray synchrotron emission. We analyzed the deep observations of the XMM-Newton SN 1006 Large Program. We performed spatially resolved spectral analysis of a set of small regions in the nonthermal limbs and studied the X…
The northwestern ejecta knot in SN 1006
2012
Aims: We want to probe the physics of fast collision-less shocks in supernova remnants. In particular, we are interested in the non-equilibration of temperatures and particle acceleration. Specifically, we aim to measure the oxygen temperature with regards to the electron temperature. In addition, we search for synchrotron emission in the northwestern thermal rim. Methods: This study is part of a dedicated deep observational project of SN 1006 using XMM-Newton, which provides us with currently the best resolution spectra of the bright northwestern oxygen knot. We aim to use the reflection grating spectrometer to measure the thermal broadening of the O vii line triplet by convolving the emis…
Detailed study of SNR G306.3–0.9 using XMM-Newton and Chandra observations
2016
Aims. We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant (SNR) G306.3-0.9 in detail to obtain constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. Methods. We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of G306.3-0.9 in detail. A spatially resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations, available in the archive, were also used to constrain the progenitor supernova and study the environment in which the remnant evol…