C.D.S. - SIMBAD4 rel 1.7 - 2020.07.12CEST10:05:16

2016A&A...596A..46M - Astronomy and Astrophysics, volume 596A, 46-46 (2016/12-1)

Optical spectroscopy of the microquasar GRS 1758-258: a possible intermediate mass system?


Abstract (from CDS):

Context. GRS 1758-258 is one of two prototypical microquasars towards the Galactic center direction discovered almost a quarter of a century ago. The system remains poorly studied in the optical domain due to its counterpart being a very faint and absorbed target in a crowded region of the sky.
Aims. Our aim is to investigate GRS 1758-258 in order to shed light on the nature of the stellar binary components. In particular, the main physical parameters of the donor star, such as the mass or the spectral type, are not yet well constrained.
Methods. GRS 1758-258 has remained so far elusive to optical spectroscopy owing to its observational difficulties. Here, we use this traditional tool of stellar astronomy at low spectral resolution with a 10m class telescope and a long slit spectrograph.
Results. An improved spectrum is obtained as compared to previous work. The quality of the data does not allow the detection of emission or absorption features but, nevertheless, we manage to partially achieve our aims comparing the de-reddened continuum with the spectral energy distribution expected from an irradiated disc model and different donor star templates.
Conclusions. We tentatively propose that GRS 1758-258 does not host a giant star companion. Instead, a main sequence star with mid-A spectral type appears to better agree with our data. The main impacts of this finding are the possibility that we are dealing with an intermediate mass system and, in this case, the prediction of an orbital period significantly shorter than previously proposed.

Abstract Copyright: © ESO, 2016

Journal keyword(s): stars: individual: GRS 1758-258 - X-rays: binaries - infrared: stars

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 Ross 640 WD* 16 28 25.0030292072 +36 46 15.849157470   14.01   13.9   DZA5.5 168 0
2 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1701 1
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11542 0
4 2XMM J180112.4-254436 LXB 18 01 12.40 -25 44 36.1           ~ 361 1

    Equat.    Gal    SGal    Ecl

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