2014A&A...563A.115P


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.08CEST04:24:19

2014A&A...563A.115P - Astronomy and Astrophysics, volume 563A, 115-115 (2014/3-1)

Unveiling the environment surrounding low-mass X-ray binary SAX J1808.4-3658.

PINTO C., COSTANTINI E., FABIAN A.C., KAASTRA J.S. and IN'T ZAND J.J.M.

Abstract (from CDS):

Low-mass X-ray binaries (LMXBs) are a natural workbench to study accretion disk phenomena and optimal background sources to measure elemental abundances in the interstellar medium (ISM). In high-resolution XMM-Newton spectra, the LMXB SAX J1808.4-3658 in the past showed a neon column density significantly higher than expected given its small distance, presumably due to additional absorption from a neon-rich circumstellar medium (CSM). It is possible to detect intrinsic absorption from the CSM by evidence of Keplerian motions or outflows. For this purpose, we analyze a recent, deep (100ks long), high-resolution Chandra/LETGS spectrum of SAX J1808.4-3658 in combination with archival data. We estimated the column densities of the different absorbers through the study of their absorption lines. We used both empirical and physical models involving photo- and collisional-ionization to determine the nature of the absorbers. The abundances of the cold interstellar gas match the solar values as expected given the proximity of the X-ray source. For the first time in this source, we detected neon and oxygen blueshifted absorption lines, which can be well modeled with outflowing photoionized gas. The wind is neon rich (Ne/O>3) and may originate from processed, ionized gas near the accretion disk or its corona. The kinematics (v=500-1000km/s) are indeed similar to those seen in other accretion disks. We also discovered a system of emission lines with very high Doppler velocities (v∼24000km/s) originating presumably closer to the compact object. Additional observations and UV coverage are needed to accurately determine the abundances and the ionization structure of the wind.

Abstract Copyright:

Journal keyword(s): plasmas - techniques: spectroscopic - ISM: abundances - X-rays: binaries - X-rays: bursts - X-rays: ISM

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 V* V1055 Ori LXB 06 17 07.3 +09 08 13   18.80 18.5     ~ 506 1
2 NGC 5548 Sy1 14 17 59.5401093128 +25 08 12.600227883   14.35 13.73     ~ 2391 0
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11535 0
4 V* V4580 Sgr LXB 18 08 27.54 -36 58 44.3   16.81 16.51     ~ 870 0
5 X Sgr X-4 LXB 18 23 40.57 -30 21 40.6   19.06 18.81     ~ 900 1
6 V* V691 CrA LXB 18 25 46.8186056396 -37 06 18.529015318 14.30 15.20 15.1     ~ 400 0
7 4U 2129+12 LXB 21 29 58.3124 +12 10 02.670 14.50 15.70 15.8     ~ 301 1

    Equat.    Gal    SGal    Ecl

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2020.07.08-04:24:19

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