Unresolved X-ray emission in M31 and constraints on progenitors of classical novae

Bogdán, Ákos; Gilfanov, M.

doi:10.1111/j.1365-2966.2010.16476.x

Cited by 3 publications

(2 citation statements)

References 63 publications

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“…The hot plasma has a temperature of about 10 keV, which cannot be confined in the GC and, therefore, sources with a power of about 10 41 erg s −1 are required to heat the plasma (see Koyama et al 2007 and references therein). In fact, plasma outflows with velocities of 10 7 cm s −1 are observed from the nuclear region of our Galaxy (see Crocker et al 2010) and from the nucleus of Andromeda (Bogdan & Gilfanov 2010). Time variations of the 6.4 keV line and X-ray continuum emission observed in the direction of molecular clouds in the GC which are supposed to be a reflection of a giant X-ray flare occurred several hundred years ago (see Inui et al 2009;Ponti et al 2010;Terrier et al 2010 and references therein).…”

Section: Introductionmentioning

confidence: 85%

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

Cheng

Chernyshov

Dogiel

et al. 2012

ApJ

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The Fermi Large Area Telescope has recently discovered two giant gamma-ray bubbles that extend north and south of the Galactic center with diameters and heights of the order of H ∼ 10 kpc. We suggest that the periodic star capture processes by the Galactic supermassive black hole Sgr A * , with a capture rate of τ −1 cap ∼ 3 × 10 −5 yr −1 and an energy release of W ∼ 3 × 10 52 erg per capture, can result in hot plasma injecting into the Galactic halo at a wind velocity of u ∼ 10 8 cm s −1. The periodic injection of hot plasma can produce a series of shocks. Energetic protons in the bubble are re-accelerated when they interact with these shocks. We show that for energy larger than E > 10 15 eV, the acceleration process can be better described by the stochastic second-order Fermi acceleration. We propose that hadronic cosmic rays (CRs) within the "knee" of the observed CR spectrum are produced by Galactic supernova remnants distributed in the Galactic disk. Re-acceleration of these particles in the Fermi Bubble produces CRs beyond the knee. With a mean CR diffusion coefficient in this energy range in the bubble D B ∼ 3 × 10 30 cm 2 s −1 , we can reproduce the spectral index of the spectrum beyond the knee and within it. The conversion efficiency from shock energy of the bubble into CR energy is about 10%. This model provides a natural explanation of the observed CR flux, spectral indices, and matching of spectra at the knee.

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Section: Introductionmentioning

confidence: 85%

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

Cheng

Chernyshov

Dogiel

et al. 2012

ApJ

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“…Observations from ROSAT [85], XMM-Newton, and Chandra [86] reveal a diffuse X-ray component within the disk of M31, thought to result from a population of unresolved point sources. We adopt a single power-law model for the energy spectrum of 2-bounce photons from these unresolved M31 sources, with normalization and spectral index free to fit.…”

Section: E Spectral Fitmentioning

confidence: 99%

New constraints on sterile neutrino dark matter from NuSTAR M31 observations

et al. 2019

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We use a combined 1.2 Ms of NuSTAR observations of M31 to search for X-ray lines from sterile neutrino dark matter decay. For the first time in a NuSTAR analysis, we consistently take into account the signal contribution from both the focused and unfocused fields of view. We also reduce the modeling systematic uncertainty by performing spectral fits to each observation individually and statistically combining the results, instead of stacking the spectra. We find no evidence of unknown lines, and thus derive limits on the sterile neutrino parameters. Our results place stringent constraints for dark matter masses 12 keV, which reduces the available parameter space for sterile neutrino dark matter produced via neutrino mixing (e.g., in the νMSM) by approximately one-third. Additional NuSTAR observations, together with improved low-energy background modeling, could probe the remaining parameter space in the future. Lastly, we also report model-independent limits on generic dark matter decay rates and annihilation cross sections. I.via a small mixing with active neutrinos [12], which may be enhanced by the presence of primordial lepton asymmetry [13]. As the mixing angle determines both the abundance and decay rate, there is a finite window in the mass-mixing angle parameter plane in which sterile neutrinos could constitute the full DM abundance, thus allowing this scenario to be fully testable. Closing this window would imply additional physics and production mechanisms are needed to make sterile neutrinos a viable DM candidate [14][15][16][17][18][19][20][21]. The existence of sterile neutrino DM could provide strong clues for explaining neutrino mass and baryogenesis [22], such as the scenario advocated in the νMSM model [23][24][25][26].Due to several sensitive X-ray instruments, such as Chandra, Suzaku, XMM-Newton, and INTEGRAL, stringent constraints on X-ray line emission have been obtained using many different observations (e.g., Refs. [27][28][29][30][31][32][33]). Interest in these topics was heightened with the tentative detection of a 3.5-keV line from cluster observations [34], which was followed up by many observational studies . The nature of this line is still inconclusive. The line could be a signature of sterile neutrino DM [57] or other candidates [58][59][60][61][62]. However, as the line flux is weak, astrophysical modeling systematics [37,41] or new astrophysical processes [63,64] could also be the explanation. New detectors [44,56,65,66] or techniques, such as velocity spectroscopy [67,68], are likely required to fully determine its nature. (Recently, Ref. [69] claims that blank-sky observations with XMM-Newton disfavor the DM interpretation of the 3.5-keV line. On the other hand, Ref. [70] claims detection of the 3.5 keV line in the Milky Way halo up to 35 • with XMM-Newton, and arXiv:1901.01262v2 [astro-ph.HE]

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An XMM-Newton View of the Andromeda Galaxy as Explored in a Legacy Survey (New-ANGELS). I. The X-Ray Source Catalog

Huang,

Li,

Cui

et al. 2023

ApJS

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We introduce the New-ANGELS program, an XMM-Newton survey of a ∼7.2 deg2 area around M31, which aims to study the X-ray populations in the M31 disk and the X-ray-emitting hot gas in the inner halo of M31 up to 30 kpc. In this first paper, we report the catalog of 4506 detected X-ray sources and attempt to cross-identify or roughly classify them. We identify 352 single stars in the foreground, 35 globular clusters, and 27 supernova remnants associated with M31, as well as 62 active galactic nuclei, 59 galaxies, and one galaxy cluster in the background. We uniquely classify 236 foreground stars and 17 supersoft sources based on their X-ray colors. X-ray binaries (83 low-mass and one high-mass) are classified based on their X-ray colors and X-ray variabilities. The remaining X-ray sources either have too low signal-to-noise ratios to calculate their X-ray colors or do not have a unique classification, so are regarded as unclassified. The X-ray source catalog is published online. Studies of the X-ray source populations and the contribution of X-ray sources in the unresolved X-ray emissions based on this catalog will be published in companion papers.

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Unresolved X-ray emission in M31 and constraints on progenitors of classical novae

Cited by 3 publications

References 63 publications

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

New constraints on sterile neutrino dark matter from NuSTAR M31 observations

An XMM-Newton View of the Andromeda Galaxy as Explored in a Legacy Survey (New-ANGELS). I. The X-Ray Source Catalog

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Unresolved X-ray emission in M31 and constraints on progenitors of classical novae

Cited by 3 publications

References 63 publications

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >1015eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >1015eV

New constraints on sterile neutrino dark matter from NuSTAR M31 observations

An XMM-Newton View of the Andromeda Galaxy as Explored in a Legacy Survey (New-ANGELS). I. The X-Ray Source Catalog

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THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV