2005/03/09 by T. Di Salvo, R. Iaria, Mariano Méndez +6 · 6 citations
Engineering · Physics and Astronomy · #Accretion (finance) #Astronomical Observations and Instrumentation #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Corona (planetary geology) #Emission spectrum #Full width at half maximum #Line (geometry) #Neutron star #Optics #Physics #Reflection (computer programming) #Spectral line #Spectrometer #Telescope #X-ray binary #astro-ph
paper · pdf · doi:10.1086/430130
published as Astrophys.J. 623 (2005) L121-L124 · 8 pages including 2 figures. ApJ Letters, in press
arxiv created 2005/03/09 · openalex publication_date 2005/03/16 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
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 Kα 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 Lyα 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 Kα 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.