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We present a spectral analysis of NuSTAR and NICER observations of the luminous, persistently accreting neutron star (NS) low-mass X-ray binary Cygnus X-2. The data were divided into different branches that the source traces out on the…

High Energy Astrophysical Phenomena · Physics 2022-03-14 R. M. Ludlam , E. M. Cackett , J. A. García , J. M. Miller , A. L. Stevens , A. C. Fabian , J. Homan , M. NG , S. Guillot , D. J. K. Buisson , D. Chakrabarty

We discuss recent Chandra and XMM-Newton observations of the bright isolated neutron star RX J1856.5-3754 and suggest that the absence of any line features is due to effects of a high magnetic field strength (~10^13 G). Using different…

Astrophysics · Physics 2009-11-10 J. E. Truemper , V. Burwitz , F. Haberl , V. E. Zavlin

Context: The hierarchical model of galaxy formation suggests that galaxies are continuously growing. However, our position inside the Milky Way prevents us from studying the disk edge. Truncations are low surface brightness features located…

Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical and UV bands. We present a re-reduction of the archival optical and infrared…

High Energy Astrophysical Phenomena · Physics 2014-11-10 Gökçe Özsükan , K. Yavuz Ekşi , Valeri Hambaryan , Ralph Neuhäuser , Markus M. Hohle , Christian Ginski , Klaus Werner

The Swift satellite monitored the quiescence of the low-mass X-ray binary transient Aql X-1 on a weekly basis during the March-November 2012 interval. A total of 42 observations were carried out in the soft X-ray (0.3-10 keV) band with the…

High Energy Astrophysical Phenomena · Physics 2021-01-27 F. Coti Zelati , S. Campana , P. D'Avanzo , A. Melandri

Calculations have been made of fall-back disk heating by the pulsar wind as distinct from the soft X-rays emitted by the neutron-star surface. The relation between these heating rates and measured near-infrared fluxes in the K and Ks bands…

Astrophysics · Physics 2009-11-13 P. B. Jones

The high-mass X-ray binary and accreting X-ray pulsar IGR J16393-4643 was observed by NuSTAR in the 3-79 keV energy band for a net exposure time of 50 ks. We present the results of this observation which enabled the discovery of a cyclotron…

We analyze archival Chandra HRC observations of the ultra luminous accreting pulsar M82-X2 (NuSTAR J095551+6940.8), and determine an upper limit of $< 1.7\times 10^{38}$~erg/s to its luminosity at an epoch at which it was undetected.…

High Energy Astrophysical Phenomena · Physics 2016-03-09 Simone Dall'Osso , Rosalba Perna , Alessandro Papitto , Enrico Bozzo , Luigi Stella

Observational evidence has been accumulating that thermonuclear X-ray bursts ignited on the surface of neutron stars influence the surrounding accretion flow. Here, we exploit the excellent sensitivity of NuSTAR up to 79 keV to analyze the…

High Energy Astrophysical Phenomena · Physics 2016-01-20 N. Degenaar , K. I. I. Koljonen , D. Chakrabarty , E. Kara , D. Altamirano , J. M. Miller , A. C. Fabian

We identify sources with extremely hard X-ray spectra (i.e., with photon indices of Gamma<0.6 in the 13 sq. deg. NuSTAR serendipitous survey, to search for the most highly obscured AGNs detected at >10 keV. Eight extreme NuSTAR sources are…

We analyzed two observations of the low-mass black hole X-ray binary MAXI J1348-630 from Nuclear Spectroscopic Telescope Array (NuSTAR) during low hard state and hard intermediate state in the 2019 outburst. The reflection components are…

High Energy Astrophysical Phenomena · Physics 2023-04-27 Hanji Wu , Wei Wang , Na Sai

We report on two NuSTAR observations of GRS 1741.9-2853, a faint neutron star low mass X-ray binary burster located 10' away from the Galactic center. NuSTAR detected the source serendipitously as it was emerging from quiescence: its…

Recent observations of two black hole candidates (GX 339-4 and J1753.5-0127) in the low-hard state (L_X/L_Edd ~ 0.003-0.05) suggest the presence of a cool accretion disk very close to the innermost stable orbit of the black hole. This runs…

Astrophysics · Physics 2009-11-13 Caroline D'Angelo , Dimitrios Giannios , Cornelis Dullemond , Henk Spruit

We present the broadband spectral analysis of all the six hard, intermediate and soft state NuSTAR observations of the recently discovered transient black hole X-ray binary MAXI J1348-630 during its first outburst in 2019. We first model…

High Energy Astrophysical Phenomena · Physics 2021-09-14 Sudip Chakraborty , Ajay Ratheesh , Sudip Bhattacharyya , John A. Tomsick , Francesco Tombesi , Keigo Fukumura , Gaurava K. Jaisawal

Observations of the cyclotron resonance scattering feature in the X-ray spectrum of GX 301-2 suggest that the surface field of the neutron star is B_CRSF ~ 4 x 10^{12}G. The same value has been derived in modelling the rapid spin-up…

High Energy Astrophysical Phenomena · Physics 2012-07-24 N. R. Ikhsanov , M. H. Finger

The Vela region has been observed for 1.7 Ms in November 2005 by the INTEGRAL satellite. We present preliminary spectral and temporal results of Vela X-1, an eclipsing neutron star hosted in a wind-accreting high-mass X-ray binary system.…

A number of studies have revealed variability from neutron star low-mass X-ray binaries during quiescence. Such variability is not well characterised, or understood, but may be a common property that has been missed due to lack of multiple…

High Energy Astrophysical Phenomena · Physics 2015-05-27 E. M. Cackett , J. K. Fridriksson , J. Homan , J. M. Miller , R. Wijnands

We present a catalog of hard X-ray sources in a square-degree region surveyed by NuSTAR in the direction of the Norma spiral arm. This survey has a total exposure time of 1.7 Ms, and typical and maximum exposure depths of 50 ks and 1 Ms,…

As part of a multiwavelength study of the unusual radio supernova remnant DA 495, we present observations made with the Chandra X-ray Observatory. Imaging and spectroscopic analysis confirms the previously detected X-ray source at the heart…

Astrophysics · Physics 2009-11-13 Z. Arzoumanian , S. Safi-Harb , T. L. Landecker , R. Kothes , F. Camilo

The deepest XMM-Newton mosaic map of the central 1.5 deg of the Galaxy is presented, including a total of about 1.5 Ms of EPIC-pn cleaned exposures in the central 15" and about 200 ks outside. This compendium presents broad-band X-ray…

High Energy Astrophysical Phenomena · Physics 2015-08-26 G. Ponti , M. R. Morris , R. Terrier , F. Haberl , R. Sturm , M. Clavel , S. Soldi , A. Goldwurm , P. Predehl , K. Nandra , G. Belanger , R. S. Warwick , V. Tatischeff
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