The field of the TeV source HESS J1804-216 in X-rays and other wavelengths

O. Kargaltsev, George Pavlov, G. P. Garmire

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The field of the extended TeV source HESS J1804-216 was serendipitously observed with the Chandra ACIS detector on 2005 May 4. The data reveal several X-ray sources within the bright part of HESS J1804-216. The brightest of these objects, CXOU J180432.4-214009, which has been also detected with Swift (2005 November 3) and Suzaku (2006 April 6), is consistent with being a pointlike source, with the 0.3-7 keV flux Fx = (1.7 ±0.2) × 10-13ergs s-1 cm-2. Its hard and strongly absorbed spectrum can be fitted by the absorbed power-law model with the best-fit photon index Γ ≈ 0.45 and hydrogen column density n H ≈4 × 1022 cm-2, both with large uncertainties due to the strong correlation between these parameters. A search for pulsations resulted in a 106 s period candidate, which has a low significance of 97.9%, however. We found no infrared-optical counterparts for this source. The second brightest source, CXOU J180441.9-214224, which has been detected with Suzaku, is either extended or multiple, with the flux F x∼ 1 × 1013 ergs cm-2 s-1. We found a nearby M dwarf within the X-ray source extension, which could contribute a fraction of the observed X-ray flux. The remaining sources are very faint (Fx < 3 × 10-14 ergs cm-2 s_1), and at least some of them are likely associated with nearby stars. Although one or both of the two brighter X-ray sources could be faint accreting binaries or remote pulsars with pulsar wind nebulae (hence possible TeV sources), their relation to HESS J1804-216 remains elusive. The possibility that HESS J1804-216 is powered by the relativistic wind from the young pulsar B1800-21, located at a distance of ∼10 pc from the TeV source, still remains a more plausible option.

Original languageEnglish (US)
Pages (from-to)643-654
Number of pages12
JournalAstrophysical Journal
Volume670
Issue number1
DOIs
StatePublished - Nov 20 2007

Fingerprint

wavelength
wavelengths
erg
x rays
pulsars
power law
hydrogen
nebulae
stars
detectors
photons
parameter
young
detector
index

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kargaltsev, O. ; Pavlov, George ; Garmire, G. P. / The field of the TeV source HESS J1804-216 in X-rays and other wavelengths. In: Astrophysical Journal. 2007 ; Vol. 670, No. 1. pp. 643-654.
@article{3a4719b9e10443d881f557a6f6374661,
title = "The field of the TeV source HESS J1804-216 in X-rays and other wavelengths",
abstract = "The field of the extended TeV source HESS J1804-216 was serendipitously observed with the Chandra ACIS detector on 2005 May 4. The data reveal several X-ray sources within the bright part of HESS J1804-216. The brightest of these objects, CXOU J180432.4-214009, which has been also detected with Swift (2005 November 3) and Suzaku (2006 April 6), is consistent with being a pointlike source, with the 0.3-7 keV flux Fx = (1.7 ±0.2) × 10-13ergs s-1 cm-2. Its hard and strongly absorbed spectrum can be fitted by the absorbed power-law model with the best-fit photon index Γ ≈ 0.45 and hydrogen column density n H ≈4 × 1022 cm-2, both with large uncertainties due to the strong correlation between these parameters. A search for pulsations resulted in a 106 s period candidate, which has a low significance of 97.9{\%}, however. We found no infrared-optical counterparts for this source. The second brightest source, CXOU J180441.9-214224, which has been detected with Suzaku, is either extended or multiple, with the flux F x∼ 1 × 1013 ergs cm-2 s-1. We found a nearby M dwarf within the X-ray source extension, which could contribute a fraction of the observed X-ray flux. The remaining sources are very faint (Fx < 3 × 10-14 ergs cm-2 s_1), and at least some of them are likely associated with nearby stars. Although one or both of the two brighter X-ray sources could be faint accreting binaries or remote pulsars with pulsar wind nebulae (hence possible TeV sources), their relation to HESS J1804-216 remains elusive. The possibility that HESS J1804-216 is powered by the relativistic wind from the young pulsar B1800-21, located at a distance of ∼10 pc from the TeV source, still remains a more plausible option.",
author = "O. Kargaltsev and George Pavlov and Garmire, {G. P.}",
year = "2007",
month = "11",
day = "20",
doi = "10.1086/521520",
language = "English (US)",
volume = "670",
pages = "643--654",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

The field of the TeV source HESS J1804-216 in X-rays and other wavelengths. / Kargaltsev, O.; Pavlov, George; Garmire, G. P.

In: Astrophysical Journal, Vol. 670, No. 1, 20.11.2007, p. 643-654.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The field of the TeV source HESS J1804-216 in X-rays and other wavelengths

AU - Kargaltsev, O.

AU - Pavlov, George

AU - Garmire, G. P.

PY - 2007/11/20

Y1 - 2007/11/20

N2 - The field of the extended TeV source HESS J1804-216 was serendipitously observed with the Chandra ACIS detector on 2005 May 4. The data reveal several X-ray sources within the bright part of HESS J1804-216. The brightest of these objects, CXOU J180432.4-214009, which has been also detected with Swift (2005 November 3) and Suzaku (2006 April 6), is consistent with being a pointlike source, with the 0.3-7 keV flux Fx = (1.7 ±0.2) × 10-13ergs s-1 cm-2. Its hard and strongly absorbed spectrum can be fitted by the absorbed power-law model with the best-fit photon index Γ ≈ 0.45 and hydrogen column density n H ≈4 × 1022 cm-2, both with large uncertainties due to the strong correlation between these parameters. A search for pulsations resulted in a 106 s period candidate, which has a low significance of 97.9%, however. We found no infrared-optical counterparts for this source. The second brightest source, CXOU J180441.9-214224, which has been detected with Suzaku, is either extended or multiple, with the flux F x∼ 1 × 1013 ergs cm-2 s-1. We found a nearby M dwarf within the X-ray source extension, which could contribute a fraction of the observed X-ray flux. The remaining sources are very faint (Fx < 3 × 10-14 ergs cm-2 s_1), and at least some of them are likely associated with nearby stars. Although one or both of the two brighter X-ray sources could be faint accreting binaries or remote pulsars with pulsar wind nebulae (hence possible TeV sources), their relation to HESS J1804-216 remains elusive. The possibility that HESS J1804-216 is powered by the relativistic wind from the young pulsar B1800-21, located at a distance of ∼10 pc from the TeV source, still remains a more plausible option.

AB - The field of the extended TeV source HESS J1804-216 was serendipitously observed with the Chandra ACIS detector on 2005 May 4. The data reveal several X-ray sources within the bright part of HESS J1804-216. The brightest of these objects, CXOU J180432.4-214009, which has been also detected with Swift (2005 November 3) and Suzaku (2006 April 6), is consistent with being a pointlike source, with the 0.3-7 keV flux Fx = (1.7 ±0.2) × 10-13ergs s-1 cm-2. Its hard and strongly absorbed spectrum can be fitted by the absorbed power-law model with the best-fit photon index Γ ≈ 0.45 and hydrogen column density n H ≈4 × 1022 cm-2, both with large uncertainties due to the strong correlation between these parameters. A search for pulsations resulted in a 106 s period candidate, which has a low significance of 97.9%, however. We found no infrared-optical counterparts for this source. The second brightest source, CXOU J180441.9-214224, which has been detected with Suzaku, is either extended or multiple, with the flux F x∼ 1 × 1013 ergs cm-2 s-1. We found a nearby M dwarf within the X-ray source extension, which could contribute a fraction of the observed X-ray flux. The remaining sources are very faint (Fx < 3 × 10-14 ergs cm-2 s_1), and at least some of them are likely associated with nearby stars. Although one or both of the two brighter X-ray sources could be faint accreting binaries or remote pulsars with pulsar wind nebulae (hence possible TeV sources), their relation to HESS J1804-216 remains elusive. The possibility that HESS J1804-216 is powered by the relativistic wind from the young pulsar B1800-21, located at a distance of ∼10 pc from the TeV source, still remains a more plausible option.

UR - http://www.scopus.com/inward/record.url?scp=39049144238&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=39049144238&partnerID=8YFLogxK

U2 - 10.1086/521520

DO - 10.1086/521520

M3 - Article

VL - 670

SP - 643

EP - 654

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

ER -