Discovery of an X-ray synchrotron nebula associated with the radio pulsar PSR B1853+01 in the supernova remnant W44

Ilana M. Harrus, John Hughes, David J. Helfand

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Abstract

We report the detection, using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to detect any significant X-ray emission (pulsed or unpulsed) from the pulsar. In addition, no high-energy emission (≳4 keV) has been detected previously from W44. Over the 0.5-4.0 keV band, the ASCA data show soft thermal emission from W44, with a morphology very similar to that observed earlier by Einstein and ROSAT. In the high-energy band (4.0-9.5 keV), the SNR is, for the most part, invisible, although a source coincident with the position of PSR B1853+01 is evident. The observed ASCA spectra are consistent with a power-law origin (photon index ∼2.3) for the X-ray emission from this source at a flux level (flux density ∼0.5 μJy at 1 keV) consistent with previous upper limits. The maximum allowed size for the source is determined directly from the ASCA data (<5′), while the minimum size is derived from the nondetection of a point source in the ROSAT HRI data (≳30″). Timing analysis of the hard X-ray source failed to detect pulsations at the pulsar's period. Based on these lines of evidence, we conclude that the new hard source in W44 represents an X-ray synchrotron nebula associated with PSR B1853+01, rather than the beamed output of the pulsar itself. This discovery adds W44 to the small group of previously known plerionic SNRs. This nebula lies at the low end of, but is consistent with, the correlation between X-ray luminosity and pulsar spin-down energy loss found for such objects, lending further support to our interpretation.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume464
Issue number2 PART II
StatePublished - Jun 20 1996
Externally publishedYes

Fingerprint

supernova remnants
nebulae
pulsars
synchrotrons
radio
astrophysics
cosmology
x rays
energy
thermal emission
point sources
energy bands
point source
power law
flux density
energy dissipation
luminosity
time measurement
output
photons

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{def24db2d1004f98a0bdec88d1e7d20a,
title = "Discovery of an X-ray synchrotron nebula associated with the radio pulsar PSR B1853+01 in the supernova remnant W44",
abstract = "We report the detection, using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to detect any significant X-ray emission (pulsed or unpulsed) from the pulsar. In addition, no high-energy emission (≳4 keV) has been detected previously from W44. Over the 0.5-4.0 keV band, the ASCA data show soft thermal emission from W44, with a morphology very similar to that observed earlier by Einstein and ROSAT. In the high-energy band (4.0-9.5 keV), the SNR is, for the most part, invisible, although a source coincident with the position of PSR B1853+01 is evident. The observed ASCA spectra are consistent with a power-law origin (photon index ∼2.3) for the X-ray emission from this source at a flux level (flux density ∼0.5 μJy at 1 keV) consistent with previous upper limits. The maximum allowed size for the source is determined directly from the ASCA data (<5′), while the minimum size is derived from the nondetection of a point source in the ROSAT HRI data (≳30″). Timing analysis of the hard X-ray source failed to detect pulsations at the pulsar's period. Based on these lines of evidence, we conclude that the new hard source in W44 represents an X-ray synchrotron nebula associated with PSR B1853+01, rather than the beamed output of the pulsar itself. This discovery adds W44 to the small group of previously known plerionic SNRs. This nebula lies at the low end of, but is consistent with, the correlation between X-ray luminosity and pulsar spin-down energy loss found for such objects, lending further support to our interpretation.",
author = "Harrus, {Ilana M.} and John Hughes and Helfand, {David J.}",
year = "1996",
month = "6",
day = "20",
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volume = "464",
journal = "Astrophysical Journal",
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}

Discovery of an X-ray synchrotron nebula associated with the radio pulsar PSR B1853+01 in the supernova remnant W44. / Harrus, Ilana M.; Hughes, John; Helfand, David J.

In: Astrophysical Journal, Vol. 464, No. 2 PART II, 20.06.1996.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Discovery of an X-ray synchrotron nebula associated with the radio pulsar PSR B1853+01 in the supernova remnant W44

AU - Harrus, Ilana M.

AU - Hughes, John

AU - Helfand, David J.

PY - 1996/6/20

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N2 - We report the detection, using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to detect any significant X-ray emission (pulsed or unpulsed) from the pulsar. In addition, no high-energy emission (≳4 keV) has been detected previously from W44. Over the 0.5-4.0 keV band, the ASCA data show soft thermal emission from W44, with a morphology very similar to that observed earlier by Einstein and ROSAT. In the high-energy band (4.0-9.5 keV), the SNR is, for the most part, invisible, although a source coincident with the position of PSR B1853+01 is evident. The observed ASCA spectra are consistent with a power-law origin (photon index ∼2.3) for the X-ray emission from this source at a flux level (flux density ∼0.5 μJy at 1 keV) consistent with previous upper limits. The maximum allowed size for the source is determined directly from the ASCA data (<5′), while the minimum size is derived from the nondetection of a point source in the ROSAT HRI data (≳30″). Timing analysis of the hard X-ray source failed to detect pulsations at the pulsar's period. Based on these lines of evidence, we conclude that the new hard source in W44 represents an X-ray synchrotron nebula associated with PSR B1853+01, rather than the beamed output of the pulsar itself. This discovery adds W44 to the small group of previously known plerionic SNRs. This nebula lies at the low end of, but is consistent with, the correlation between X-ray luminosity and pulsar spin-down energy loss found for such objects, lending further support to our interpretation.

AB - We report the detection, using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to detect any significant X-ray emission (pulsed or unpulsed) from the pulsar. In addition, no high-energy emission (≳4 keV) has been detected previously from W44. Over the 0.5-4.0 keV band, the ASCA data show soft thermal emission from W44, with a morphology very similar to that observed earlier by Einstein and ROSAT. In the high-energy band (4.0-9.5 keV), the SNR is, for the most part, invisible, although a source coincident with the position of PSR B1853+01 is evident. The observed ASCA spectra are consistent with a power-law origin (photon index ∼2.3) for the X-ray emission from this source at a flux level (flux density ∼0.5 μJy at 1 keV) consistent with previous upper limits. The maximum allowed size for the source is determined directly from the ASCA data (<5′), while the minimum size is derived from the nondetection of a point source in the ROSAT HRI data (≳30″). Timing analysis of the hard X-ray source failed to detect pulsations at the pulsar's period. Based on these lines of evidence, we conclude that the new hard source in W44 represents an X-ray synchrotron nebula associated with PSR B1853+01, rather than the beamed output of the pulsar itself. This discovery adds W44 to the small group of previously known plerionic SNRs. This nebula lies at the low end of, but is consistent with, the correlation between X-ray luminosity and pulsar spin-down energy loss found for such objects, lending further support to our interpretation.

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