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Title: XMM-NEWTON MEASUREMENT OF THE GALACTIC HALO X-RAY EMISSION USING A COMPACT SHADOWING CLOUD

Abstract

Observations of interstellar clouds that cast shadows in the soft X-ray background can be used to separate the background Galactic halo emission from the local emission due to solar wind charge exchange (SWCX) and/or the Local Bubble (LB). We present an XMM-Newton observation of a shadowing cloud, G225.60–66.40, that is sufficiently compact that the on- and off-shadow spectra can be extracted from a single field of view (unlike previous shadowing observations of the halo with CCD-resolution spectrometers, which consisted of separate on- and off-shadow pointings). We analyzed the spectra using a variety of foreground models: one representing LB emission, and two representing SWCX emission. We found that the resulting halo model parameters (temperature T {sub h} ≈ 2 × 10{sup 6} K, emission measure E{sub h}≈4×10{sup −3} cm{sup −6} pc) were not sensitive to the foreground model used. This is likely due to the relative faintness of the foreground emission in this observation. However, the data do favor the existence of a foreground. The halo parameters derived from this observation are in good agreement with those from previous shadowing observations, and from an XMM-Newton survey of the Galactic halo emission. This supports the conclusion that the latter results are not subject tomore » systematic errors, and can confidently be used to test models of the halo emission.« less

Authors:
; ; ;  [1]
  1. Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States)
Publication Date:
OSTI Identifier:
22364405
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CHARGE EXCHANGE; EMISSION SPECTROSCOPY; INTERSTELLAR SPACE; MILKY WAY; RESOLUTION; SOFT X RADIATION; SOLAR WIND; STAR MODELS

Citation Formats

Henley, David B., Shelton, Robin L., Cumbee, Renata S., and Stancil, Phillip C., E-mail: dbh@physast.uga.edu. XMM-NEWTON MEASUREMENT OF THE GALACTIC HALO X-RAY EMISSION USING A COMPACT SHADOWING CLOUD. United States: N. p., 2015. Web. doi:10.1088/0004-637X/799/2/117.
Henley, David B., Shelton, Robin L., Cumbee, Renata S., & Stancil, Phillip C., E-mail: dbh@physast.uga.edu. XMM-NEWTON MEASUREMENT OF THE GALACTIC HALO X-RAY EMISSION USING A COMPACT SHADOWING CLOUD. United States. doi:10.1088/0004-637X/799/2/117.
Henley, David B., Shelton, Robin L., Cumbee, Renata S., and Stancil, Phillip C., E-mail: dbh@physast.uga.edu. Sun . "XMM-NEWTON MEASUREMENT OF THE GALACTIC HALO X-RAY EMISSION USING A COMPACT SHADOWING CLOUD". United States. doi:10.1088/0004-637X/799/2/117.
@article{osti_22364405,
title = {XMM-NEWTON MEASUREMENT OF THE GALACTIC HALO X-RAY EMISSION USING A COMPACT SHADOWING CLOUD},
author = {Henley, David B. and Shelton, Robin L. and Cumbee, Renata S. and Stancil, Phillip C., E-mail: dbh@physast.uga.edu},
abstractNote = {Observations of interstellar clouds that cast shadows in the soft X-ray background can be used to separate the background Galactic halo emission from the local emission due to solar wind charge exchange (SWCX) and/or the Local Bubble (LB). We present an XMM-Newton observation of a shadowing cloud, G225.60–66.40, that is sufficiently compact that the on- and off-shadow spectra can be extracted from a single field of view (unlike previous shadowing observations of the halo with CCD-resolution spectrometers, which consisted of separate on- and off-shadow pointings). We analyzed the spectra using a variety of foreground models: one representing LB emission, and two representing SWCX emission. We found that the resulting halo model parameters (temperature T {sub h} ≈ 2 × 10{sup 6} K, emission measure E{sub h}≈4×10{sup −3} cm{sup −6} pc) were not sensitive to the foreground model used. This is likely due to the relative faintness of the foreground emission in this observation. However, the data do favor the existence of a foreground. The halo parameters derived from this observation are in good agreement with those from previous shadowing observations, and from an XMM-Newton survey of the Galactic halo emission. This supports the conclusion that the latter results are not subject to systematic errors, and can confidently be used to test models of the halo emission.},
doi = {10.1088/0004-637X/799/2/117},
journal = {Astrophysical Journal},
number = 2,
volume = 799,
place = {United States},
year = {Sun Feb 01 00:00:00 EST 2015},
month = {Sun Feb 01 00:00:00 EST 2015}
}