Soft X-Rays from the Vicinity of the North Polar Spur.

Bunner, A. N.; Coleman, P.L.; Kraushaar, W. L.; McCammon, D.

doi:10.1086/180893

Cited by 40 publications

(13 citation statements)

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“…The region was soon found to emit enhanced soft X-rays (Bunner et al 1972). ROSAT observations later revealed that the NPS region was filled with a hot gas, with a prominent feature shown to be located inside Loop I ridges in a 0.75 keV soft Xray image (Snowden et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Far-Ultraviolet Observations of the Loop I/North Polar Spur Region

Park

Kang

Seon

et al. 2007

ApJ

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The results of diffuse far-ultraviolet observations of the Loop I/North Polar Spur (NPS) region are presented in this Letter. Several important ionic emission lines, including C iv, Si ii*, Si iv, and Al ii, were detected. Fluorescent emission lines from hydrogen molecules were also seen in the spectra. A spectral image made with C iv emission shows a shell-like feature colocated with the X-ray NPS. This feature is located just inside the Loop I radio ridges. Another interesting C iv feature is seen at the inner edge of the "interaction ring," where the cold interstellar medium is in direct contact with the X-ray-bright hot gas. The present observation is in good agreement with a model of recent supernova explosion in an inhomogeneous medium, possibly disturbed by previous multiple supernova explosions.

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Section: Introductionmentioning

confidence: 99%

Far-Ultraviolet Observations of the Loop I/North Polar Spur Region

Park

Kang

Seon

et al. 2007

ApJ

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“…A weak non-thermal radio source, located at /"= 315.4° and b ll = -2.3° in the Milne list of probable SNR, lies close to the X-ray source Cen X-l. First seen in 1965 NRL survey (Byram et al, 1966) this faint X-ray source has been observed latterly by the Leicester (Cooke and Pounds, 1971) and LRL ) Groups, though not by UHURU. Since each positive sighting was with plastic window detectors, these apparently conflicting results might be reconciled if the X-ray spectrum is steep, as indeed the 40' extension of the radio source would suggest.…”

Section: B Eta Carinaementioning

confidence: 87%

“…A University of Wisconsin rocket experiment flown in December 1969 detected a further low energy source in Cygnus (Coleman et al, 1971), designated Cyg X-6. The rather large error box (1.7° x 6° at la) includes a part of the SNR HB 21, a remnant similar in its radio appearance to Cyg Loop.…”

Section: Hb21mentioning

confidence: 99%

X-Radiation from Supernova Remnants

Pounds

1973

Symp. - Int. Astron. Union

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Abstract. Available X-ray observations of supernova remnants are reviewed. The number of SNR seen above 2 keV remains small after inclusion of the UHURU results and for only the Crab Nebula is the data adequate to clearly indicate the radiation mechanism. The increasing importance of low energy X-ray studies (below 1 keV) of older and relatively nearby remnants is noted. Brief discussion is given of the relation of the X-ray data to current ideas of the evolution of SNR.This meeting marks the 10th anniversary of the discovery of the first cosmic X-ray source, Scorpius X-l. In the following few years it was considered that most of the newly discovered and obviously powerful sources were associated with supernovae and, indeed, the first identification of a cosmic X-ray source was with the Crab Nebula in 1964 (Bowyer et al, 1964). This expectation has not been realised and of the 40 or so Galactic sources known by the end of 1970 only four others had been reliably linked with supernova remnants, these being Cas A, SN 1572 (Tycho's nova), Vel X and Pup A. A comparison of a further forty sources listed in the second UHURU catalogue (Giacconi et al, 1972) with the positions of 120 non-thermal Galactic radio sources (Milne, 1970 andDownes, 1971) (generally thought to be SNR) has revealed only three additional associations, none of which are considered con vincing. Conversely, a number of X-ray sources previously associated with nearby SNR such as Nor X-l, Nor X-2 and a source near Doradus in the LMC, have been ruled out by improved UHURU locations.The available X-ray results on all the above (certain and possible) SNR/X-ray source associations are briefly reviewed below, including recent soft X-ray observa tions which indicate that SNR sources may play an increasingly important role in the newly emerging regime of X-ray astronomy below 1 keV photon energy.

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“…They propose that the spurs, because they are nearby, provide the source of emission in the direction of the galactic poles while the integral effect of old type II supernova remnants accounts for the emission in the plane. Recently, the North Polar Spur has been observed to be a source of soft X-rays (Bunner et al, 1972). However, other spur structures such as Loop III and parts of other loop structures were observed by Davidsen et al (1972) and not found to be X-ray emitters with an upper limit significantly below that of the North Polar Spur.…”

Section: Low Energy Galactic X-raysmentioning

confidence: 96%

“…(LRL) group (Palmieri et al, 1971) using a somewhat different proportional counter dectector with a considerably thinner window of Formvar, rather than the Kimfol used by the other two groups, find a flux near 6"=50° of 270 photons (cm2 s ster k e V ) " 1 which is in reasonable agreement with the other results. However, they also Bunner et al, 1972).…”

Section: Observational Datamentioning

confidence: 99%

The Soft X-Ray Background

Friedman¹,

Fritz²,

Shulman³

et al. 1973

Symp. - Int. Astron. Union

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Abstract. A survey of soft X-ray background observations in the 0.1-10 keV range is presented. In the region above 1 keV, recent results on point X-ray sources are discussed and their integrated contri bution to the diffuse background is estimated. However, the average luminosity of various classes of extragalactic X-ray sources is still not sufficiently well known to permit this estimate to be made with any certainty. A discussion is given of recent observations at energies below 1 keV where the effects of interstellar absorption are important. It is argued that although some fraction of the background radiation in the 0.1-1 keV range must be galactic in origin, there is still substantial evidence for an extragalactic component. Proposed theories for generating both the galactic and extragalactic X-ray background are briefly reviewed.

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Soft X-Rays from the Vicinity of the North Polar Spur.

Cited by 40 publications

References 0 publications

Far-Ultraviolet Observations of the Loop I/North Polar Spur Region

Far-Ultraviolet Observations of the Loop I/North Polar Spur Region

X-Radiation from Supernova Remnants

The Soft X-Ray Background

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