skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465

Abstract

We present X-ray observations of the as of yet unidentified very high-energy (VHE) {gamma}-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ksec XMM-Newton observation of HESS J1640-465 in September 2005 represents a significant improvement in sensitivity and angular resolution over previous ASCA studies in this region. These new data show a hard-spectrum X-ray emitting object at the centroid of the H.E.S.S. source, within the shell of the radio Supernova Remnant (SNR) G338.3-0.0. This object is consistent with the position and flux previously measured by both ASCA and Swift-XRT but is now shown to be significantly extended. We argue that this object is very likely the counterpart to HESS J1640-465 and that both objects may represent the Pulsar Wind Nebula of an as of yet undiscovered pulsar associated with G338.3-0.0.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
900607
Report Number(s):
SLAC-PUB-12295
Journal ID: ISSN 0004-637X; ASJOAB; astro-ph/0701166; TRN: US200711%%359
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophys.J.662:517-524,2007
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ENERGY RANGE; PULSARS; RESOLUTION; SENSITIVITY; SUPERNOVA REMNANTS; Astrophysics,ASTRO

Citation Formats

Funk, S., Hinton, J.A., Puhlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., Wagner, S., /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL, Funk, S., Hinton, J.A., Puehlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., and Wagner, S.. XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465. United States: N. p., 2007. Web. doi:10.1086/516567.
Funk, S., Hinton, J.A., Puhlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., Wagner, S., /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL, Funk, S., Hinton, J.A., Puehlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., & Wagner, S.. XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465. United States. doi:10.1086/516567.
Funk, S., Hinton, J.A., Puhlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., Wagner, S., /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL, Funk, S., Hinton, J.A., Puehlhofer, G., Aharonian, F.A., Hofmann, W., Reimer, O., and Wagner, S.. Mon . "XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465". United States. doi:10.1086/516567. https://www.osti.gov/servlets/purl/900607.
@article{osti_900607,
title = {XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465},
author = {Funk, S. and Hinton, J.A. and Puhlhofer, G. and Aharonian, F.A. and Hofmann, W. and Reimer, O. and Wagner, S. and /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL and Funk, S. and Hinton, J.A. and Puehlhofer, G. and Aharonian, F.A. and Hofmann, W. and Reimer, O. and Wagner, S.},
abstractNote = {We present X-ray observations of the as of yet unidentified very high-energy (VHE) {gamma}-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ksec XMM-Newton observation of HESS J1640-465 in September 2005 represents a significant improvement in sensitivity and angular resolution over previous ASCA studies in this region. These new data show a hard-spectrum X-ray emitting object at the centroid of the H.E.S.S. source, within the shell of the radio Supernova Remnant (SNR) G338.3-0.0. This object is consistent with the position and flux previously measured by both ASCA and Swift-XRT but is now shown to be significantly extended. We argue that this object is very likely the counterpart to HESS J1640-465 and that both objects may represent the Pulsar Wind Nebula of an as of yet undiscovered pulsar associated with G338.3-0.0.},
doi = {10.1086/516567},
journal = {Astrophys.J.662:517-524,2007},
number = ,
volume = ,
place = {United States},
year = {Mon Mar 05 00:00:00 EST 2007},
month = {Mon Mar 05 00:00:00 EST 2007}
}
  • We present a Chandra X-ray observation of the very high energy gamma-ray source HESS J1640 - 465. We identify a point source surrounded by a diffuse emission that fills the extended object previously detected by XMM-Newton at the centroid of the HESS source, within the shell of the radio supernova remnant (SNR) G338.3 - 0.0. The morphology of the diffuse emission strongly resembles that of a pulsar wind nebula (PWN) and extends asymmetrically to the southwest of a point source presented as a potential pulsar. The spectrum of the putative pulsar and compact nebula are well characterized by an absorbedmore » power-law model which, for a reasonable N{sub H} value of 14 x 10{sup 22} cm{sup -2}, exhibit an index of 1.1 and 2.5 respectively, typical of Vela-like PWNe. We demonstrate that, given the H I absorption features observed along the line of sight, the SNR and the H II surrounding region are probably connected and lie between 8 kpc and 13 kpc. The resulting age of the system is between 10 and 30 kyr. For a 10 kpc distance (also consistent with the X-ray absorption) the 2-10 keV X-ray luminosities of the putative pulsar and nebula are L{sub PSR} approx 1.3 x 10{sup 33} d {sup 2}{sub 10kpc} erg s{sup -1} and L{sub PWN} approx 3.9 x 10{sup 33} d {sup 2}{sub 10} erg s{sup -1} (d {sub 10} = d/10 kpc). Both the flux ratio of L {sub PWN}/L{sub PSR} approx 3.4 and the total luminosity of this system predict a pulsar spin-down power around E-dotapprox4 x 10{sup 36} erg s{sup -1}. We finally consider several reasons for the asymmetries observed in the PWN morphology and discuss the potential association with the HESS source in terms of a time-dependent one-zone leptonic model.« less
  • We present XMM-Newton observations of the dusty Wolf-Rayet (W-R) star WR 48a. This is the first detection of this object in X-rays. The XMM-Newton EPIC spectra are heavily absorbed and the presence of numerous strong emission lines indicates a thermal origin of the WR 48a X-ray emission, with dominant temperature components at kT{sub cool} {approx} 1 keV and kT{sub hot} {approx} 3 keV, the hotter component dominating the observed flux. No significant X-ray variability was detected on timescales {<=}1 day. Although the distance to WR 48a is uncertain, if it is physically associated with Open clusters Danks 1 and 2more » at d {approx}4 kpc, then the resultant X-ray luminosity L{sub X}{approx} 10{sup 35} erg s{sup -1} makes it the most X-ray luminous W-R star in the Galaxy detected so far, after the black hole candidate Cyg X-3. We assume the following scenarios as the most likely explanation for the X-ray properties of WR 48a: (1) colliding stellar winds in a wide WR+O binary system, or in a hierarchical triple system with non-degenerate stellar components and (2) accretion shocks from the WR 48a wind onto a close companion (possibly a neutron star). More specific information about WR 48a and its wind properties will be needed to distinguish between the above possibilities.« less
  • We report the discovery of a 206 ms pulsar associated with the TeV γ-ray source HESS J1640–465 using the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray observatory. PSR J1640–4631 lies within the shell-type supernova remnant (SNR) G338.3–0.0, and coincides with an X-ray point source and putative pulsar wind nebula (PWN) previously identified in XMM-Newton and Chandra images. It is spinning down rapidly with period derivative P-dot = 9.758(44) × 10{sup –13}, yielding a spin-down luminosity E-dot = 4.4 × 10{sup 36} erg s{sup –1}, characteristic age τ{sub c}≡P/2 P-dot = 3350 yr, and surface dipole magnetic field strength B{sub s} =more » 1.4 × 10{sup 13} G. For the measured distance of 12 kpc to G338.3–0.0, the 0.2-10 TeV luminosity of HESS J1640–465 is 6% of the pulsar's present E-dot . The Fermi source 1FHL J1640.5–4634 is marginally coincident with PSR J1640–4631, but we find no γ-ray pulsations in a search using five years of Fermi Large Area Telescope (LAT) data. The pulsar energetics support an evolutionary PWN model for the broadband spectrum of HESS J1640–465, provided that the pulsar's braking index is n ≈ 2, and that its initial spin period was P {sub 0} ∼ 15 ms.« less
  • We have analyzed three XMM-Newton observations of the central part of the unidentified TeV {gamma}-ray source HESS J1804-216. We focus on two X-ray sources, 2XMMi J180442.0-214221 (Src 1) and 2XMMi J180432.5-214009 (Src 2), which were suggested to be the possible X-ray counterparts to the TeV source. We discover a 2.93 hr X-ray periodicity from Src 1, with the pulse profile explained with a self-eclipsing pole in an eclipsing polar. Src 2 exhibits a strong Fe emission line (FWHM {approx} 0.3 keV and equivalent width {approx}0.8 keV) and large X-ray variability on timescales of hours and is probably an intermediate polar.more » Thus Src 1 and Src 2 are probably two field sources not responsible for the TeV emission. The observations were contaminated by strong stray light from a nearby bright source, and we see no clear extended X-ray emission that can be attributed to the supernova remnant G8.7-0.1, a popular possible association with the TeV source. The other possible association, the pulsar wind nebula candidate PSR J1803-2137, shows little long-term variability compared with a previous Chandra observation. Many point sources were serendipitously detected, but most of them are probably normal stars. Three new candidate compact object systems (other than Src 1, Src 2, and PSR J1803-2137) are also found. They are far away from the TeV source and are probably also magnetic cataclysmic variables, thus unlikely to be responsible for the TeV emission.« less
  • We report on γ-ray analysis of the region containing the bright TeV source HESS J1640–465 and the close-by TeV source HESS J1641–463 using 64 months of observations with the Fermi Large Area Telescope (LAT). Previously only one GeV source was reported in this region and was associated with HESS J1640–465. With an increased data set and the improved sensitivity afforded by the reprocessed data (P7REP) of the LAT, we now report the detection, morphological study, and spectral analysis of two distinct sources above 100 MeV. The softest emission in this region comes from the TeV source HESS J1641–463 which ismore » well fitted with a power law of index Γ = 2.47 ± 0.05 ± 0.06 and presents no significant γ-ray signal above 10 GeV, which contrasts with its hard spectrum at TeV energies. The Fermi-LAT spectrum of the second TeV source, HESS J1640–465 is well described by a power-law shape of index Γ = 1.99 ± 0.04 ± 0.07 that links up naturally with the spectral data points obtained by the High Energy Stereoscopic System (H.E.S.S.). These new results provide new constraints concerning the identification of these two puzzling γ-ray sources.« less