Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'487'895
Articles rated: 2609

29 March 2024
 
  » arxiv » astro-ph/9801215

 Article overview


The identification of the transient X-ray pulsar Cepheus X-4 with a Be/X-ray binary
Jean-Marc Bonnet-Bidaud ; Martine Mouchet ;
Date 22 Dec 1997
Subject astro-ph
AbstractWe present long slit spectral (375-725 nm) observations of the proposed identification of the transient 66s X-ray pulsar Cep X-4=GS2138+56. Spectra show features typical of Be/X-ray binaries. Superimposed on a weak emission from the IC 1396 nebula, strong H$alpha$ (4.5 nm EW) and H$eta$ (0.3 nm EW) lines are seen in emission with the other Balmer lines in absorption. Significant interstellar absorption features are also detected, including a strong Na I doublet (589 nm) and diffuse bands at 443, 578 and 628 nm. From the shape of the continuum as well as the lines present in the spectrum, a most probable spectral type of B1-B2V is derived with a reddening of E$_{B-V}$=1.3$pm$0.1. The reddening value is corroborated by the measure of interstellar absorption features, except for the sodium line which appears to be in excess and may be partly from circumstellar origin. The optical absorption is fully consistent with the column density derived from X-ray spectra, therefore confirming the identification. Despite apparent spatial coincidence, the source is located much further away than the local intervening nebula IC1396. The best estimate of the distance is D=(3.8$pm$0.6) kpc, which places the source in the outer Perseus arm of the Galaxy. At this distance, the X-ray quiescent luminosity is (3-6) 10$^{33}$ erg.s$^{-1}$, thus comparable to typical Be/X-ray binary low states.
Source arXiv, astro-ph/9801215
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica