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Title: A SECOND NEUTRON STAR IN M4?

Abstract

We show that the optical counterpart of the X-ray source CX 1 in M4 is a {approx}20th magnitude star, located in the color-magnitude diagram on (or very close to) the main sequence of the cluster, and exhibiting sinusoidal variations of the flux. We find the X-ray flux to be also periodically variable, with X-ray and optical minima coinciding. Stability of the optical light curve, lack of UV-excess, and unrealistic mean density resulting from period-density relation for semidetached systems speak against the original identification of CX 1 as a cataclysmic variable. We argue that the X-ray active component of this system is a neutron star (probably a millisecond pulsar).

Authors:
; ; ;  [1];  [2]
  1. Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland)
  2. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22047872
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 750; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COLOR; COSMIC PHOTONS; COSMIC X-RAY SOURCES; DENSITY; DIAGRAMS; MAIN SEQUENCE STARS; NEUTRON STARS; PERIODICITY; PULSARS; STABILITY; VISIBLE RADIATION; X RADIATION

Citation Formats

Kaluzny, J., Rozanska, A., Rozyczka, M., Krzeminski, W., and Thompson, Ian B.. A SECOND NEUTRON STAR IN M4?. United States: N. p., 2012. Web. doi:10.1088/2041-8205/750/1/L3.
Kaluzny, J., Rozanska, A., Rozyczka, M., Krzeminski, W., & Thompson, Ian B.. A SECOND NEUTRON STAR IN M4?. United States. doi:10.1088/2041-8205/750/1/L3.
Kaluzny, J., Rozanska, A., Rozyczka, M., Krzeminski, W., and Thompson, Ian B.. Tue . "A SECOND NEUTRON STAR IN M4?". United States. doi:10.1088/2041-8205/750/1/L3.
@article{osti_22047872,
title = {A SECOND NEUTRON STAR IN M4?},
author = {Kaluzny, J. and Rozanska, A. and Rozyczka, M. and Krzeminski, W. and Thompson, Ian B.},
abstractNote = {We show that the optical counterpart of the X-ray source CX 1 in M4 is a {approx}20th magnitude star, located in the color-magnitude diagram on (or very close to) the main sequence of the cluster, and exhibiting sinusoidal variations of the flux. We find the X-ray flux to be also periodically variable, with X-ray and optical minima coinciding. Stability of the optical light curve, lack of UV-excess, and unrealistic mean density resulting from period-density relation for semidetached systems speak against the original identification of CX 1 as a cataclysmic variable. We argue that the X-ray active component of this system is a neutron star (probably a millisecond pulsar).},
doi = {10.1088/2041-8205/750/1/L3},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 750,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2012},
month = {Tue May 01 00:00:00 EDT 2012}
}
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