Search Publications
An X-ray study of changing-look active galactic nuclei
Titarchuk, Lev; Seifina, Elena; Mishin, Egor
A significant number of changing-look active galactic nuclei (CL AGNs) have been identified to date. In this work, we study what happens to the X-ray spectrum during CL events. We use the example of the nearby CL Seyfert named NGC 1566, which has been observed by Swift, NuSTAR, XMM-Newton, and Suzaku. We applied the Comptonization model to describ…
XMM-Newton observation of the TeV-discovered supernova remnant HESS J1534-571
Santangelo, A.; Pühlhofer, G.; Sasaki, M. +3 more
We report the results obtained from XMM-Newton observations of the TeV-detected supernova remnant (SNR) HESS J1534-571. We focus on the nature of the cosmic-ray particle content in the SNR, which is revealed by its γ-ray emission. No signatures of X-ray synchrotron emission were detected from the SNR. This is consistent with earlier results obtain…
A shock near the virial radius of the Perseus Cluster
Simionescu, A.; Kaastra, J. S.; Zhang, X. +6 more
Context. Previous X-ray studies of the Perseus Cluster, consisting of 85 Suzaku pointings along eight azimuthal directions, revealed a particularly steep decrease in the projected temperature profile near the virial radius (∼r200) towards the northwest (NW).
Aims: To further explore this shock candidate, another 4 Suzaku observatio…
X-ray study of the merging galaxy cluster Abell 3411-3412 with XMM-Newton and Suzaku
Simionescu, A.; Kaastra, J. S.; Zhang, X. +3 more
Context. Previous Chandra observations of the
Joint XMM-Newton and NuSTAR observations of the reflection spectrum of III Zw 2
Savolainen, Tuomas; Chamani, Wara; Koljonen, Karri
Detecting and modeling the reprocessed hard X-ray emission component in the accretion flow, the so-called reflection spectrum, is a main tool used to estimate black hole spins in a wide range of astrophysical black holes, regardless of their mass or distance. In this work, we study the X-ray spectra of the Seyfert I galaxy III Zw 2 by using multie…
H.E.S.S. and Suzaku observations of the Vela X pulsar wind nebula
Santangelo, A.; Quirrenbach, A.; Bregeon, J. +222 more
Context. Pulsar wind nebulae (PWNe) represent the most prominent population of Galactic very-high-energy gamma-ray sources and are thought to be an efficient source of leptonic cosmic rays. Vela X is a nearby middle-aged PWN, which shows bright X-ray and TeV gamma-ray emission towards an elongated structure called the cocoon.
Aims: Since TeV …
Variations on a theme: the puzzling behaviour of Schulte 12
Nazé, Yaël; Mahy, Laurent; Rauw, Gregor +2 more
One of the first massive stars detected in X-rays, Schulte 12 has remained a puzzle in several aspects. In particular, its extreme brightness both in the visible and X-ray ranges is intriguing. Thanks to Swift and XMM-Newton observations covering ∼5000 d, we report the discovery of a regular 108 d modulation in X-ray flux of unknown origin. The mi…
Spectral analysis of the dipping LMXB system XB 1916-053
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
Context. XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and with a Comptonization component with an electron temperature of 9.4 keV and a photon index Γ between 2…
X-ray study of the double radio relic Abell 3376 with Suzaku
Urdampilleta, I.; Kaastra, J. S.; Mernier, F. +5 more
We present an X-ray spectral analysis of the nearby double radio relic merging cluster Abell 3376 (z = 0.046), observed with the Suzaku XIS instrument. These deep (∼360 ks) observations cover the entire double relic region in the outskirts of the cluster. These diffuse radio structures are amongst the largest and arc-shaped relics observed in comb…
Multiple cyclotron line-forming regions in GX 301-2
Pottschmidt, K.; Natalucci, L.; Kretschmar, P. +6 more
We present two observations of the high-mass X-ray binary GX 301-2 with NuSTAR, taken at different orbital phases and different luminosities. We find that the continuum is well described by typical phenomenological models, like a very strongly absorbed NPEX model. However, for a statistically acceptable description of the hard X-ray spectrum we re…