Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

Brian Thomas; Robin Corbet; Thomas Augusteijn; Paul Callanan; Alan P. Smale

doi:10.1086/172624

Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

Brian Thomas
, Robin Corbet
, Thomas Augusteijn
, Paul Callanan
, Alan P. Smale

Research output: Contribution to journal › Article › peer-review

Abstract

Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state (V_Φ=0.5 = 17.18 ± 002) while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve.

Original language	English
Pages (from-to)	651-655
Number of pages	5
Journal	Astrophysical Journal
Volume	408
Issue number	2
DOIs	https://doi.org/10.1086/172624
Publication status	Published - 10 May 1993
Externally published	Yes

Keywords

Binaries: close
Stars: individual (EXO 0748-676)
X-rays: stars

Access to Document

10.1086/172624

Cite this

@article{6fdb9a3d081246b3b0f644b6b6e7cb58,

title = "Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676",

abstract = "Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state (VΦ=0.5 = 17.18 ± 002) while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve.",

keywords = "Binaries: close, Stars: individual (EXO 0748-676), X-rays: stars",

author = "Brian Thomas and Robin Corbet and Thomas Augusteijn and Paul Callanan and Smale, \{Alan P.\}",

year = "1993",

month = may,

day = "10",

doi = "10.1086/172624",

language = "English",

volume = "408",

pages = "651--655",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

TY - JOUR

T1 - Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

AU - Thomas, Brian

AU - Corbet, Robin

AU - Augusteijn, Thomas

AU - Callanan, Paul

AU - Smale, Alan P.

PY - 1993/5/10

Y1 - 1993/5/10

N2 - Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state (VΦ=0.5 = 17.18 ± 002) while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve.

AB - Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state (VΦ=0.5 = 17.18 ± 002) while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve.

KW - Binaries: close

KW - Stars: individual (EXO 0748-676)

KW - X-rays: stars

UR - https://www.scopus.com/pages/publications/12044254955

U2 - 10.1086/172624

DO - 10.1086/172624

M3 - Article

AN - SCOPUS:12044254955

SN - 0004-637X

VL - 408

SP - 651

EP - 655

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -

Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this