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The discovery of photospheric absorption lines in XMM-Newton spectra of the X-ray bursting neutron star in EXO0748-676 by Cottam and collaborators allows us to constrain the neutron star mass-radius ratio from the measured gravitational…

Astrophysics · Physics 2009-11-13 Thomas Rauch , Valery Suleimanov , Klaus Werner

Physical parameters of both the mass donor and compact object can be constrained in X-ray binaries with well-defined eclipses, as our survey of wind-fed supergiant X-ray binaries (SGXBs) IGR J16393-4643, IGR J16418-4532, IGR J16479-4514,…

High Energy Astrophysical Phenomena · Physics 2015-08-06 Joel B. Coley , Robin H. D. Corbet , Hans A. Krimm

The radius of neutron stars can in principle be measured via the normalisation of a blackbody fitted to the X-ray spectrum during thermonuclear (type-I) X-ray bursts, although few previous studies have addressed the reliability of such…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Duncan K. Galloway , Nathanael Lampe

We present the results of a spectroscopic monitoring campaign of the OB-star companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3. High-resolution optical spectra obtained with UVES on the ESO Very Large Telescope are used…

Hercules X-1/HZ Hercules (Her X-1/HZ Her) is an X-ray binary monitored by multiple X-ray missions since last century. With the abundance of long-term observations, we present a complete set of orbital light-curves of Her X-1/HZ Her during…

High Energy Astrophysical Phenomena · Physics 2022-03-14 Yuyang Wang , Denis Leahy

To understand the formation and evolution of solar-type stars in the solar neighborhood, we need to measure their stellar parameters to high accuracy. We present a catalogue of accurate stellar parameters for 451 stars that represent the…

Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of…

We report on spectral and intensity variability analysis from a Chandra/ACIS-S observation of the transient, type-I X-ray bursting low-mass X-ray binary Cen X-4. The quiescent X-ray spectrum during this observation is statistically…

X-ray eclipse mapping is a promising modelling technique, capable of constraining the mass and/or radius of neutron stars (NSs) or black holes (BHs) in eclipsing binaries and probing any structure surrounding the companion star. In…

High Energy Astrophysical Phenomena · Physics 2022-05-25 Amy H. Knight , Adam Ingram , Matthew Middleton

Pulse profile modeling of X-ray data from NICER is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory ($\chi$EFT), and masses and tidal…

Using deep Chandra observations of the globular cluster M28, we study the quiescent X-ray emission of a neutron star in a low-mass X-ray binary in order to constrain the chemical composition of the neutron star atmosphere and the equation…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Mathieu Servillat , C. O. Heinke , W. C. G. Ho , J. E. Grindlay , J. Hong , M. van den Berg , S. Bogdanov

Measuring the time evolution of the effective surface temperature of neutron stars can provide invaluable information on the properties of their dense cores. Here, we report on a new Chandra observation of the transient neutron star…

High Energy Astrophysical Phenomena · Physics 2021-12-21 N. Degenaar , D. Page , J. van den Eijnden , M. V. Beznogov , R. Wijnands , M. Reynolds

The thermal evolution of a neutron star is studied by including the energy loss due to axion emission. Two axion models and three types of neutron-star matter equation of state are used with the effects of nucleon superfluidity properly…

Astrophysics · Physics 2007-05-23 Hideyuki Umeda , Naoki Iwamoto , Sachiko Tsuruta , Letao Qin , Ken'ichi Nomoto

The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but…

Solar and Stellar Astrophysics · Physics 2015-05-20 Adam L. Kraus , Roy A. Tucker , Michael I. Thompson , Eric R. Craine , Lynne A. Hillenbrand

Using observations of X-ray pulsar Her X-1 by the Imaging X-ray Polarimetry Explorer, we report on a highly significant ($>17\sigma$) detection of the polarization signal from an accreting neutron star. The observed degree of the linear…

High Energy Astrophysical Phenomena · Physics 2023-01-16 Victor Doroshenko , Juri Poutanen , Sergey S. Tsygankov , Valery F. Suleimanov , Matteo Bachetti , Ilaria Caiazzo , Enrico Costa , Alessandro Di Marco , Jeremy Heyl , Fabio La Monaca , Fabio Muleri , Alexander A. Mushtukov , George G. Pavlov , Brian D. Ramsey , John Rankin , Andrea Santangelo , Paolo Soffitta , Rüdiger Staubert , Martin C. Weisskopf , Silvia Zane , Iván Agudo , Lucio A. Antonelli , Luca Baldini , Wayne H. Baumgartner , Ronaldo Bellazzini , Stefano Bianchi , Stephen D. Bongiorno , Raffaella Bonino , Alessandro Brez , Niccolò Bucciantini , Fiamma Capitanio , Simone Castellano , Elisabetta Cavazzuti , Stefano Ciprini , Alessandra De Rosa , Ettore Del Monte , Laura Di Gesu , Niccolò Di Lalla , Immacolata Donnarumma , Michal Dovciak , Steven R. Ehlert , Teruaki Enoto , Yuri Evangelista , Sergio Fabiani , Riccardo Ferrazzoli , Javier A. Garcia , Shuichi Gunji , Kiyoshi Hayashida , Wataru Iwakiri , Svetlana G. Jorstad , Vladimir Karas , Takao Kitaguchi , Jeffery J. Kolodziejczak , Henric Krawczynski , Luca Latronico , Ioannis Liodakis , Simone Maldera , Alberto Manfreda , Frédéric Marin , Andrea Marinucci , Alan P. Marscher , Herman L. Marshall , Giorgio Matt , Ikuyuki Mitsuishi , Tsunefumi Mizuno , C. -Y. Ng , Stephen L. O'Dell , Nicola Omodei , Chiara Oppedisano , Alessandro Papitto , Abel L. Peirson , Matteo Perri , Melissa Pesce-Rollins , Maura Pilia , Andrea Possenti , Simonetta Puccetti , Ajay Ratheesh , Roger W. Romani , Carmelo Sgrò , Patrick Slane , Gloria Spandre , Rashid A. Sunyaev , Toru Tamagawa , Fabrizio Tavecchio , Roberto Taverna , Yuzuru Tawara , Allyn F. Tennant , Nicolas E. Thomas , Francesco Tombesi , Alessio Trois , Roberto Turolla , Jacco Vink , Kinwah Wu , Fei Xie

Determining the maximum possible neutron star (NS) mass places limits on the equation of state (EoS) of ultra-dense matter. The mass of NSs in low mass X-ray binaries can be determined from the binary mass function, providing independent…

High Energy Astrophysical Phenomena · Physics 2022-01-26 Amy H. Knight , Adam Ingram , Matthew Middleton , Jeremy Drake

Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting…

Astrophysics · Physics 2009-11-13 Guillermo Torres

The X-ray binary Her X-1 consists of an accreting neutron star and the optical component HZ Her. The 35-day X-ray superorbital variability of this system is known since its discovery in 1972 by the Uhuru satellite and is believed to be…

In this paper we present and analyse determinations of effective temperatures of planet-hosting stars using infrared (IR) photometry. One of our goals is the comparison with spectroscopic temperatures to evaluate the presence of systematic…

Astrophysics · Physics 2009-11-10 I. Ribas , E. Solano , E. Masana , A. Gimenez

Using the Yale stellar evolution code, models of mu Her based on asteroseismic measurements are constructed. A $\chi^{2}$ minimization is performed to approach the best modeling parameters which reproduce the observations within their…

Solar and Stellar Astrophysics · Physics 2014-11-20 W. Yang , X. Meng