<i>Chandra</i>Observations of MBM 12 and Models of the Local Bubble

Edgar, R. J.; Plucinsky, Paul P.; Wargelin, Bradford J.; Freeman, Peter E.; Biller, Beth

doi:10.1086/428568

Cited by 41 publications

(75 citation statements)

References 58 publications

(82 reference statements)

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“…In Figure 4, Foreground emission taking into account the optical depth of the shadows. Data taken from Smith et al (2005Smith et al ( , 2007; Henley & Shelton (2008); Gupta et al (2009) controversy of the dominant emission mechanism in the local interstellar inedimn. …”

Section: Resultsmentioning

confidence: 99%

“…The perfect candidate for this kind of observing strategy is NIBM 12, a nearby high-galactic (l, b -159°, -34°), low-ecliptic (A, (3 47°, 3") latitude molecular cloud , with a column density of -4x 1021 c111-2 (Smith et al 2005), which is optically thick for the oxygen lines energies that are of interest in our analysis (optical depths of 3.5 and 2.4 for O VII and O VIII respectively). Early estimates of the distance to NIBM 12 were controversial and have placed it between 65 and 360 pc (Hobbs et al 1986;Andersson et al 2002).…”

Section: Introductionmentioning

confidence: 99%

“…However, ROSAT's lack of spectral resolution within the bands, did not allow the separation of the O VII from the O VIII line emission, the background continuum and possible other spectral features. Smith et al (2005) repeated the MBM 12 observations using the CHANDRA ACIS instrument in August 2000, but their results were adversely influenced by a strong C,oronal Mass Ejection (CME). They measured particularly strong O VII and O VIII line emission with a surface brightness of 1.79±0.55 LU and 2.34±0.36 LU respectively, much larger than Snowden et al (1993)'s limits.…”

Section: Introductionmentioning

confidence: 99%

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XMM-NEWTONOBSERVATIONS OF MBM 12: MORE CONSTRAINTS ON THE SOLAR WIND CHARGE EXCHANGE AND LOCAL BUBBLE EMISSIONS

Koutroumpa

Edgar

Küntz

et al. 2010

ApJ

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We present the first analysis of an XMAI-Newton observation of the nearby molecular cloud MBNI 12. We find that in the direction of MBM 12 the total O VII (0.57 keV) triplet emission is 1.8+0" photons cm -2 s _u sr -1 (or Line Units -LU) while for the O VIII (0.65 keV) line emission we find a 3Q upper limit of <1 LU. We also use a heliospheric model to calculate the O VII and O VIII emission generated by Solar Wind Charge-eXchange (SWCX) which we compare to the XMM-Newton observations. This comparison provides new constraints on the relative heliospheric and Local Bubble contributions to the local diffuse X-ray background. The heliospheric SWCX model predicts 0.82 LU for O VII, which accounts for -,16±15 eic of the observed value, and 0.33 LU for the O VIII line emission consistent with the XMM-Newton observed value. We discuss our results in combination with previous observations of the MBM 12 with CHANDRA and Suzaku.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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XMM-NEWTONOBSERVATIONS OF MBM 12: MORE CONSTRAINTS ON THE SOLAR WIND CHARGE EXCHANGE AND LOCAL BUBBLE EMISSIONS

Koutroumpa

Edgar

Küntz

et al. 2010

ApJ

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“…Similarly, the column density, apart from during the outburst itself, has remained fairly constant throughout these observations at about 4−5 × 10 22 cm −2 . Smith et al (2005) show that the hydrogen column density due to the MBM12 molecular cloud varies across the cloud between 2−15 × 10 21 cm −2 . This suggests that a column density of at least 3 × 10 22 cm −2 is intrinsic to XY Ari.…”

Section: A Continued Decline From Outburst?mentioning

confidence: 94%

A precessing accretion disc in the intermediate polar XY Arietis?

Norton¹,

Mukai²

2007

A&A

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Context. XY Ari is the only intermediate polar to show deep X-ray eclipses of its white dwarf. Previously published observations with Ginga and Chandra have also revealed a broad X-ray orbital modulation, roughly antiphased with the eclipse, and presumed to be due to absorption in an extended structure near the edge of an accretion disc. The X-ray pulse profile is generally seen to be double-peaked, although a single-peaked pulse was seen by RXTE during an outburst in 1996. Aims. We intended to investigate the cause of the broad orbital modulation in XY Ari to better understand the accretion flow in this system and other intermediate polars.Methods. We observed XY Ari with RXTE and analysed previously unpublished archival observations of the system made with ASCA and XMM-Newton. These observations comprise six separate visits and span about ten years.Results. The various X-ray observations show that the broad orbital modulation varies in phase and significance, then ultimately disappears entirely in the last few years. In addition, the X-ray pulse profile shows variations in depth and shape, and in the recent RXTE observations displays no evidence for changes in hardness ratio. Conclusions. The observed changes indicates that both the pulse profile and the orbital modulation are solely due to geometrical effects at the time of the RXTE observations, rather than phase-dependent variations in photoelectric absorption as seen previously. We suggest that this is evidence for a precessing, tilted accretion disc in this system. The precession of the disc moves structures out of our line of sight both at its outer edge (changing the orbital modulation) and at its inner edge where the accretion curtains are anchored (changing the pulse profile).

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“…In addition to the pioneering work noting the so-called Long Term Enhancements (subsequently known to be due to SWCX emission) within ROSAT observations (Snowden et al 1995), the assignment of such enhancements to SWCX emission has also been observed in studies undertaken using data from Suzaku (Fujimoto et al 2007;Bautz et al 2009) and Chandra (Smith et al 2005). Enhancements in soft X-ray band XMM-Newton spectra have been attributed to SWCX contamination in the literature (Snowden et al 2004;Kuntz & Snowden 2008;Snowden et al 2009;Henley & Shelton 2008).…”

Section: Introductionmentioning

confidence: 92%

Identifying XMM-Newtonobservations affected by solar wind charge exchange – Part II

Carter

Sembay

Read

2011

A&A

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Aims. We wished to analyse a sample of observations from the XMM-Newton Science Archive to search for evidence of exospheric solar wind charge exchange (SWCX) emission. Methods. We analysed 3012 observations up to and including revolution 1773. The method employed extends from that of the previously published paper by these authors on this topic. We detect temporal variability in the diffuse X-ray background within a narrow low-energy band and contrast this to a continuum. The low-energy band was chosen to represent the key indicators of charge exchange emission and the continuum was expected to be free of SWCX.Results. Approximately 3.4% of observations studied are affected. We discuss our results with reference to the XMM-Newton mission. We further investigate remarkable cases by considering the state of the solar wind and the orientation of XMM-Newton at the time of these observations. We present a method to approximate the expected emission from observations, based on given solar wind parameters taken from an upstream solar wind monitor. We also compare the incidence of SWCX cases with solar activity. Conclusions. We present a comprehensive study of the majority of the suitable and publically available XMM-Newton Science Archive to date, with respect to the occurrence of SWCX enhancements. We present our SWCX-affected subset of this dataset. The mean exospheric-SWCX flux observed within this SWCX-affected subset was 15.4 keV cm −2 s −1 sr −1 in the energy band 0.25 to 2.5 keV. Exospheric SWCX is preferentially detected when XMM-Newton observes through the subsolar region of the Earth's magnetosheath. The model developed to estimate the expected emission returns fluxes within a factor of a few of the observed values in the majority of cases, with a mean value at 83%.

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ChandraObservations of MBM 12 and Models of the Local Bubble

Cited by 41 publications

References 58 publications

XMM-NEWTONOBSERVATIONS OF MBM 12: MORE CONSTRAINTS ON THE SOLAR WIND CHARGE EXCHANGE AND LOCAL BUBBLE EMISSIONS

XMM-NEWTONOBSERVATIONS OF MBM 12: MORE CONSTRAINTS ON THE SOLAR WIND CHARGE EXCHANGE AND LOCAL BUBBLE EMISSIONS

A precessing accretion disc in the intermediate polar XY Arietis?

Identifying XMM-Newtonobservations affected by solar wind charge exchange – Part II

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