6533b861fe1ef96bd12c5af3

RESEARCH PRODUCT

A Broad Iron Line in the Chandra High Energy Transmission Grating Spectrum of 4U 1705-44

Luciano BurderiR. IariaG. LavagettoMariano MendezN. R. RobbaLuigi StellaM. Van Der KlisT. Di Salvo

subject

PhysicsSpectrometerAstrophysics::High Energy Astrophysical PhenomenaX-rays : starsAstronomy and AstrophysicsAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysicsaccretion accretion diskstars : individual (4U 1705-44)Coronastars : neutronNeutron starFull width at half maximumSpace and Planetary Scienceindividual (4U 1705-44); stars : neutron; X-rays : binaries; X-rays : general; X-rays : stars [accretion accretion disks; stars]Reflection (physics)Emission spectrumLow MassX-rays : binarieLine (formation)X-rays : general

description

We present the results of a Chandra 30 ks observation of the low-mass X-ray binary and atoll source 4U 1705-44. Here we concentrate on the study of discrete features in the energy spectrum at energies below ~3 keV, as well as on the iron Kalpha line, using the High Energy Transmission Grating Spectrometer on board the Chandra satellite. Below 3 keV, three narrow emission lines are found at 1.47, 2.0, and 2.6 keV. The 1.47 and 2.6 keV lines are probably identified with Lyalpha emission from Mg XII and S XVI, respectively. The identification of the feature at ~2.0 keV is uncertain because of the presence of an instrumental feature at the same energy. The iron Kalpha line at ~6.5 keV is found to be intrinsically broad (FWHM~1.2 keV); its width can be explained by reflection from a cold accretion disk extending down to ~15 km from the neutron star center or by Compton broadening in the external parts of a hot (~2 keV) Comptonizing corona. We finally report here precise X-ray coordinates of the source.

yearjournalcountryeditionlanguage
2005-03-16
10.1086/430130http://hdl.handle.net/10447/26267