Open AccessSpectroscopic identification of the infrared counterpart to GX5‐1
Author(s) -
Bandyopadhyay R. M.,
Shahbaz T.,
Charles P. A.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06519.x
Subject(s) - physics , astrometry , astrophysics , infrared , photometry (optics) , astronomy , emission spectrum , spectroscopy , infrared spectroscopy , spectral line , stars , quantum mechanics
Using CGS4 on UKIRT, we have obtained a 1.95–2.45 μm infrared (IR) spectrum of the primary candidate counterpart to the bright Z LMXB GX5‐1. IR photometry by Naylor, Charles & Longmore and the astrometry of Jonker et al. had previously identified this star as the most likely counterpart to GX5‐1. The spectrum presented here clearly shows Brackett γ and He lines in emission, for the first time confirming the identity of the counterpart. Similar to our previous spectroscopy of the Z source LMXBs Sco X‐1 and Sco X‐2 (Bandyopadhyay et al. 1999), the K ‐band spectrum of GX5‐1 shows emission lines only. We briefly discuss the implications of this spectrum for the nature of the Z sources.