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Title: THE TeV BINARY HESS J0632+057 IN THE LOW AND HIGH X-RAY STATE

Abstract

We report on a 40 ks Chandra observation of the TeV emitting high-mass X-ray binary HESS J0632+057 performed in 2011 February during a high state of X-ray and TeV activity. We have used the ACIS-S camera in continuous clocking mode to search for a possible X-ray pulsar in this system. Furthermore, we compare the emission of the source during this high state, with its X-ray properties during a low state of emission, caught by a 47 ks XMM-Newton observation on 2007 September. We did not find any periodic or quasi-periodic signal in any of the two observations. We derived an average pulsed fraction 3{sigma} upper limit for the presence of a periodic signal of {approx}<35% and 25% during the low and high emission states, respectively (although this limit is strongly dependent on the frequency and the energy band). Using the best X-ray spectra derived to date for HESS J0632+057, we found evidence for a significant spectral change between the low and high X-ray emission states, with the absorption value and the photon index varying between N{sub H} {approx_equal} (2.1-4.3) x 10{sup 21} cm{sup -2} and {Gamma} {approx_equal} 1.18-1.61. In contrast to what has been observed in other TeV binaries, itmore » seems that in this source the higher the flux, the softer the X-ray spectrum.« less

Authors:
;  [1]
  1. Institut de Ciencies de l'Espai (IEEC-CSIC), Campus UAB, Torre C5, 2a planta, 08193 Barcelona (Spain)
Publication Date:
OSTI Identifier:
21562488
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 737; Journal Issue: 1; Other Information: DOI: 10.1088/2041-8205/737/1/L12; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; BINARY STARS; EMISSION; X RADIATION; X-RAY SPECTRA; ELECTROMAGNETIC RADIATION; IONIZING RADIATIONS; RADIATIONS; SORPTION; SPECTRA; STARS

Citation Formats

Rea, Nanda, and Torres, Diego F. THE TeV BINARY HESS J0632+057 IN THE LOW AND HIGH X-RAY STATE. United States: N. p., 2011. Web. doi:10.1088/2041-8205/737/1/L12.
Rea, Nanda, & Torres, Diego F. THE TeV BINARY HESS J0632+057 IN THE LOW AND HIGH X-RAY STATE. United States. doi:10.1088/2041-8205/737/1/L12.
Rea, Nanda, and Torres, Diego F. Wed . "THE TeV BINARY HESS J0632+057 IN THE LOW AND HIGH X-RAY STATE". United States. doi:10.1088/2041-8205/737/1/L12.
@article{osti_21562488,
title = {THE TeV BINARY HESS J0632+057 IN THE LOW AND HIGH X-RAY STATE},
author = {Rea, Nanda and Torres, Diego F},
abstractNote = {We report on a 40 ks Chandra observation of the TeV emitting high-mass X-ray binary HESS J0632+057 performed in 2011 February during a high state of X-ray and TeV activity. We have used the ACIS-S camera in continuous clocking mode to search for a possible X-ray pulsar in this system. Furthermore, we compare the emission of the source during this high state, with its X-ray properties during a low state of emission, caught by a 47 ks XMM-Newton observation on 2007 September. We did not find any periodic or quasi-periodic signal in any of the two observations. We derived an average pulsed fraction 3{sigma} upper limit for the presence of a periodic signal of {approx}<35% and 25% during the low and high emission states, respectively (although this limit is strongly dependent on the frequency and the energy band). Using the best X-ray spectra derived to date for HESS J0632+057, we found evidence for a significant spectral change between the low and high X-ray emission states, with the absorption value and the photon index varying between N{sub H} {approx_equal} (2.1-4.3) x 10{sup 21} cm{sup -2} and {Gamma} {approx_equal} 1.18-1.61. In contrast to what has been observed in other TeV binaries, it seems that in this source the higher the flux, the softer the X-ray spectrum.},
doi = {10.1088/2041-8205/737/1/L12},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 737,
place = {United States},
year = {2011},
month = {8}
}