Inverse Compton emission from millisecond pulsars in the Galactic bulge

Song, Deheng; Macías, Óscar; Horiuchi, Shunsaku

doi:10.1103/physrevd.99.123020

Cited by 23 publications

(44 citation statements)

References 84 publications

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“…The qualitative features with respect to variations in the diffuse models and the density profiles are the same as the bb channel for these other channels. We do not consider annihilation to e þ e − and μ þ μ − since the dominant gamma-ray contribution in these cases will arise from the IC process, causing the spatial profile to change from the DM density-squared morphology [42].…”

Section: Figmentioning

confidence: 99%

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

et al. 2020

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The extended excess toward the Galactic Center (GC) in gamma rays inferred from Fermi-LAT observations has been interpreted as being due to dark matter (DM) annihilation. Here, we perform new likelihood analyses of the GC and show that, when including templates for the stellar galactic and nuclear bulges, the GC shows no significant detection of a DM annihilation template, even after generous variations in the Galactic diffuse emission models and a wide range of DM halo profiles. We include Galactic diffuse emission models with combinations of three-dimensional inverse Compton maps, variations of interstellar gas maps, and a central source of electrons. For the DM profile, we include both spherical and ellipsoidal DM morphologies and a range of radial profiles from steep cusps to kiloparsec-sized cores, motivated in part by hydrodynamical simulations. Our derived upper limits on the dark matter annihilation flux place strong constraints on DM properties. In the case of the pure b-quark annihilation channel, our limits on the annihilation cross section are more stringent than those from the Milky Way dwarfs up to DM masses of approximately TeV and rule out the thermal relic cross section up to approximately 300 GeV. Better understanding of the DM profile, as well as the Fermi-LAT data at its highest energies, would further improve the sensitivity to DM properties.

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Section: Figmentioning

confidence: 99%

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

et al. 2020

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“…Ref. [12] finds that -ray emission from globular clusters exhibit a component that can be attributed to the inverse-Compton scattering of starlight via CR electrons produced by MSPs. Ref.…”

Section: Discussionmentioning

confidence: 99%

Millisecond Pulsars Modify the Radio-SFR Correlation

Sudoh¹,

Linden²,

Beacom³

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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The observed correlation between the far-infrared and radio luminosities of galaxies illustrates the close connection between star formation and cosmic-ray production. Intriguingly, recent LOFAR observations find a peculiar radio excess in galaxies with low star-formation rates and high stellar masses. We show that recycled/millisecond pulsars (MSPs) can dominate the nonthermal emission in these massive quiescent galaxies and explain the excess. This is in line with recent gamma-ray observation suggesting that MSPs may efficiently accelerate cosmic-ray electrons. We find that MSP-based models provide a significantly improved fit to the LOFAR data. We discuss implications for the radio and gamma-ray excesses in M31 and local electron and positron observations.

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“…Based on the discovery, the ± efficiency of the millisecond pulsars hosted by the globular clusters is estimated to be comparable to, or slightly smaller than their -ray efficiency, which is about 10%. Forthcoming TeV telescopes such as CTA [22] and LHAASO [23] may detect such an inverse Comtpon signal from the globular clusters [24] or Galactic center region [25,26].…”

Section: Discussionmentioning

confidence: 99%

“…This might require a much more ambitious observation strategy that increases the sensitivity by factor of a few at the TeV energy range. Efforts to measure the diffuse IC emission from the putative MSP population responsible for the Fermi GeV excess have been made and are very encouraging; see Song et al (2019). Alternatively, Bednarek et al (2016) studied TeV 𝛾-ray emission from MSPs taking into account the advection of 𝑒 ± with the wind from the GC.…”

Section: Tev Observations Of Globular Clustersmentioning

confidence: 99%

Evidence for inverse Compton emission from globular clusters

Song¹,

Macías²,

Horiuchi³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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Millisecond pulsars are very likely the main source of gamma-ray emission from globular clusters. However, the relative contributions of two separate emission processes-curvature radiation from millisecond pulsar magnetospheres vs. inverse Compton emission from relativistic pairs launched into the globular cluster environment by millisecond pulsars-have long been unclear. To address this, we search for evidence of inverse Compton emission in 8-year Fermi-LAT data from the directions of 157 Milky Way globular clusters. We find that the -ray luminosities of the globular clusters are correlated with their stellar encounter rates (6.4 ) and total radiation field energy density (3.8 ). We demonstrate that the gamma-ray emission of globular clusters can be resolved spectrally into two components: i) an exponentially cut-off power law and ii) a pure power law. The latter component-which we uncover at a significance of 8.2 -is most naturally interpreted as inverse Compton emission by cosmic-ray electrons and positrons injected by millisecond pulsars. The luminosity of this inverse Compton component suggests that the fraction of millisecond pulsar spin-down luminosity into relativistic leptons is similar to the fraction of the spin-down luminosity into prompt magnetospheric radiation.

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Inverse Compton emission from millisecond pulsars in the Galactic bulge

Cited by 23 publications

References 84 publications

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

Millisecond Pulsars Modify the Radio-SFR Correlation

Evidence for inverse Compton emission from globular clusters

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