Observations of M31 and M33 with the Fermi Large Area Telescope: A Galactic Center Excess in Andromeda?

Ackermann, M.; Ajello, M.; Albert, A.; Baldini, Luca; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, Pascal; Buehler, R.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiaro, G.; Ciprini, S.; Costanza, F.; Cutini, S.; D’Ammando, F.; Palma, F. de; Desiante, R.; Digel, S. W.; Lalla, N. Di; Mauro, Mattia Di; Venere, L. Di; Favuzzi, C.; Funk, S.; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Green, D.; Grenier, I. A.; Guillemot, L.; Guiriec, S.; Hayashi, K.; Hou, X.; Jóhannesson, G.; Kamae, T.; Knödlseder, J.; Kong, Albert; Kuss, M.; Mura, G. La; Larsson, Stefan; Latronico, L.; Li, J.; Longo, F.; Loparco, F.; Lubrano, P.; Maldera, S.; Malyshev, D.; Manfreda, Alberto; Martin, Pierrick; Mazziotta, M. N.; Michelson, P. F.; Mirabal, N.; Mitthumsiri, W.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, Michela; Nuss, E.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Peršić, M.; Pesce-Rollins, Melissa; Piron, F.; Porter, T. A.; Principe, G.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, O.; Sánchez‐Conde, Miguel A.; Sgrò, C.; Simone, D.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Tanaka, Keigo; Tibaldo, L.; Torres, D. F.; Troja, E.; Uchiyama, Y.; Wang, J. C.; Wood, K.; Wood, M.; Zaharijaš, Gabrijela; Zhou, Ming

doi:10.3847/1538-4357/aa5c3d

Cited by 101 publications

(154 citation statements)

References 51 publications

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“…It is noteworthy that the two targets show very similar results with the GC having slightly smaller maximum fractions than M31. This is important, as any DM contribution would need to be consistent across the two sources if the gamma-ray spectra are as similar as indicated by [23]. We also note that these results do not differ by more than a factor of two when compared to the results found by seeking the maximal ratio between the DM and observed spectra bin by bin (this will pertain to all displayed results in this section).…”

Section: Resultssupporting

confidence: 54%

“…In the Galactic Centre we follow [29] in using the J-factor for the observed region to be 2 × 10 22 GeV 2 cm −5 for a NFW profile, and J ∼ 4 × 10 23 GeV 2 cm −5 for a contracted NFW profile following the method used in [31] (and matching their best-fit DM models). While, in M31, we follow the results quoted in [23] of J ∼ 8 × 10…”

Section: Dark Matter Halossupporting

confidence: 55%

“…The cross-section limits found in this manner are equivalent to those from [21]. These cross-sections will then be employed to calculate an expected flux from DM annihilation in the GC and M31 halos, using the limits from Reticulum II and Coma separately, and comparing the resulting integrated fluxes with those from the M31 and GC data [23,29] for the given range of energies (1 to 12 GeV). The fractional contribution of DM to the integrated flux will then be…”

Section: Cross-section Constraintsmentioning

confidence: 99%

“…Since the M31 and GC gamma-ray data is binned [23,29], the DM gamma-ray flux spectrum S will also be binned for accurate comparison. We stress that the fluxes for Coma are treated differently in order for the radio and gamma-ray spectra to be calculated in a consistent manner.…”

Section: Dark Matter Induced Emissionsmentioning

confidence: 99%

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A multi-frequency analysis of possible dark matter contributions to M31 gamma-ray emissions

Beck¹,

Colafrancesco²

2017

J. Cosmol. Astropart. Phys.

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Abstract. We examine the possibility of a dark matter (DM) contribution to the recently observed gamma-ray spectrum seen in the M31 galaxy. In particular, we apply limits on Weakly Interacting Massive Particle DM annihilation cross-sections derived from the Coma galaxy cluster and the Reticulum II dwarf galaxy to determine the maximal flux contribution by DM annihilation to both the M31 gamma-ray spectrum and that of the Milky-Way Galactic Centre. We limit the energy range between 1 and 12 GeV in M31 and Galactic Centre spectra due to the limited range of former's data, as well as to encompass the high-energy gamma-ray excess observed in the latter target. In so doing, we will make use of Fermi-LAT data for all mentioned targets, as well as diffuse radio data for the Coma cluster. The multi-target strategy using both Coma and Reticulum II to derive cross-section limits, as well as multi-frequency data, ensures that our results are robust against the various uncertainties inherent in modelling of indirect DM emissions.Our results indicate that, when a Navarro-Frenk-White (or shallower) radial density profile is assumed, severe constraints can be imposed upon the fraction of the M31 and Galactic Centre spectra that can be accounted for by DM, with the best limits arising from cross-section constraints from Coma radio data and Reticulum II gamma-ray limits. These particular limits force all the studied annihilation channels to contribute 1% or less to the total integrated gamma-ray flux within both M31 and Galactic Centre targets. In contrast, considerably more, 10 − 100%, of the flux can be attributed to DM when a contracted Navarro-Frenk-White profile is assumed. This demonstrates how sensitive DM contributions to gamma-ray emissions are to the possibility of cored profiles in galaxies. The only channel consistently excluded for all targets and profiles (except for ∼ 10 GeV WIMPs) is the direct annihilation into photons.Finally, we discuss the ramifications of evidence in favour of cored halo density profiles for DM explanations of galactic gamma-ray emission.

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Section: Resultssupporting

confidence: 54%

Section: Dark Matter Halossupporting

confidence: 55%

Section: Cross-section Constraintsmentioning

confidence: 99%

Section: Dark Matter Induced Emissionsmentioning

confidence: 99%

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A multi-frequency analysis of possible dark matter contributions to M31 gamma-ray emissions

Beck¹,

Colafrancesco²

2017

J. Cosmol. Astropart. Phys.

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“…Beside the Milky Way, ten external star-forming galaxies have been firmly detected in gamma-rays with the Fermi-LAT (Ackermann et al 2012(Ackermann et al , 2017. Among these, seven are starburst and active galaxies that are more luminous at γ-ray energies compared to quiescently star forming galaxies by a factor larger than 10.…”

Section: Modelling γ-Ray Emission From Star-forming Galaxiesmentioning

confidence: 99%

Extragalactic gamma-ray background from AGN winds and star-forming galaxies in cosmological galaxy-formation models

Lamastra

Menci

Fiore

et al. 2017

A&A

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We derive the contribution to the extragalactic gamma-ray background (EGB) from AGN winds and star-forming galaxies by including a physical model for the γ-ray emission produced by relativistic protons accelerated by AGN-driven and supernova-driven shocks into a state-of-the-art semi-analytic model of galaxy formation. This is based on galaxy interactions as triggers of AGN accretion and starburst activity and on expanding blast wave as the mechanism to communicate outwards the energy injected into the interstellar medium by the active nucleus. We compare the model predictions with the latest measurement of the EGB spectrum performed by the Fermi-LAT in the range between 100 MeV and 820 GeV. We find that AGN winds can provide ∼35±15% of the observed EGB in the energy interval E γ =0.1-1 GeV, for ∼73±15% at E γ =1-10 GeV, and for ∼60±20% at E γ 10 GeV. The AGN wind contribution to the EGB is predicted to be larger by a factor of ∼3-5 than that provided by star-forming galaxies (quiescent plus starburst) in the hierarchical clustering scenario. The cumulative γ−ray emission from AGN winds and blazars can account for the amplitude and spectral shape of the EGB, assuming the standard acceleration theory, and AGN wind parameters that agree with observations. We also compare the model prediction for the cumulative neutrino background from AGN winds with the most recent IceCube data. We find that for AGN winds with accelerated proton spectral index p=2.2-2.3, and taking into account internal absorption of γ-rays, the Fermi-LAT and IceCube data could be reproduced simultaneously.

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Cosmic ray feedback in galaxies and galaxy clusters

Ruszkowski,

Pfrommer

2023

Astron Astrophys Rev

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Understanding the physical mechanisms that control galaxy formation is a fundamental challenge in contemporary astrophysics. Recent advances in the field of astrophysical feedback strongly suggest that cosmic rays (CRs) may be crucially important for our understanding of cosmological galaxy formation and evolution. The appealing features of CRs are their relatively long cooling times and relatively strong dynamical coupling to the gas. In galaxies, CRs can be close to equipartition with the thermal, magnetic, and turbulent energy density in the interstellar medium, and can be dynamically very important in driving large-scale galactic winds. Similarly, CRs may provide a significant contribution to the pressure in the circumgalactic medium. In galaxy clusters, CRs may play a key role in addressing the classic cooling flow problem by facilitating efficient heating of the intracluster medium and preventing excessive star formation. Overall, the underlying physics of CR interactions with plasmas exhibit broad parallels across the entire range of scales characteristic of the interstellar, circumgalactic, and intracluster media. Here we present a review of the state-of-the-art of this field and provide a pedagogical introduction to cosmic ray plasma physics, including the physics of wave–particle interactions, acceleration processes, CR spatial and spectral transport, and important cooling processes. The field is ripe for discovery and will remain the subject of intense theoretical, computational, and observational research over the next decade with profound implications for the interpretation of the observations of stellar and supermassive black hole feedback spanning the entire width of the electromagnetic spectrum and multi-messenger data.

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Observations of M31 and M33 with the Fermi Large Area Telescope: A Galactic Center Excess in Andromeda?

Cited by 101 publications

References 51 publications

A multi-frequency analysis of possible dark matter contributions to M31 gamma-ray emissions

A multi-frequency analysis of possible dark matter contributions to M31 gamma-ray emissions

Extragalactic gamma-ray background from AGN winds and star-forming galaxies in cosmological galaxy-formation models

Cosmic ray feedback in galaxies and galaxy clusters

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