6533b85bfe1ef96bd12bb6dc

RESEARCH PRODUCT

Discovery of 105 Hz coherent pulsations in the ultracompact binary IGR J16597-3704

Craig O. HeinkeAndrea PossentiM. BurgayEnrico BozzoNathalie DegenaarThomas J. MaccaroneGregory R. SivakoffT. Di SalvoR. IariaA. SannaRudy WijnandsA. RiggioLuciano BurderiDiego AltamiranoCarlo FerrignoArash BahramianAlessandro PapittoN. D'amicoN. D'amico

subject

PhotonAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencessymbols.namesakeAccretion accretion diskSettore FIS/05 - Astronomia E Astrofisica0103 physical sciencesBinaries: generalAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsAstrophysics::Galaxy AstrophysicsPhysicsHigh Energy Astrophysical Phenomena (astro-ph.HE)Accretion (meteorology)010308 nuclear & particles physicsgeneral; Stars: neutron; X-rays: binaries; Astronomy and Astrophysics; Space and Planetary Science [Accretion accretion disks; Binaries]Astronomy and AstrophysicsAstronomy and AstrophysicLight curveOrbital periodX-rays: binarieStars: neutronNeutron starSpace and Planetary ScienceGlobular clustersymbolsElectron temperatureAstrophysics - High Energy Astrophysical PhenomenaDoppler effect

description

We report the discovery of X-ray pulsations at 105.2 Hz (9.5 ms) from the transient X-ray binary IGR J16597-3704 using NuSTAR and Swift. The source was discovered by INTEGRAL in the globular cluster NGC 6256 at a distance of 9.1 kpc. The X-ray pulsations show a clear Doppler modulation implying an orbital period of ~46 minutes and a projected semi-major axis of ~5 lt-ms, which makes IGR J16597-3704 an ultra-compact X-ray binary system. We estimated a minimum companion mass of 0.0065 solar masses, assuming a neutron star mass of 1.4 solar masses, and an inclination angle of <75 degrees (suggested by the absence of eclipses or dips in its light-curve). The broad-band energy spectrum of the source is well described by a disk blackbody component (kT ~1.4 keV) plus a comptonised power-law with photon index ~2.3 and an electron temperature of ~30 keV. Radio pulsations from the source were searched for with the Parkes observatory and not detected.

yearjournalcountryeditionlanguage
2018-02-14
10.1051/0004-6361/201732262http://hdl.handle.net/20.500.12386/27795