INTEGRAL constraints on primordial black holes and particle dark matter. (arXiv:2004.00627v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Laha_R/0/1/0/all/0/1">Ranjan Laha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Munoz_J/0/1/0/all/0/1">Julian B. Muñoz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Slatyer_T/0/1/0/all/0/1">Tracy R. Slatyer</a>
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has
yielded unprecedented measurements of the soft gamma-ray spectrum of our
Galaxy. Here we use those measurements to set constraints on dark matter (DM)
that decays or annihilates into photons with energies $Eapprox 0.02-2$ MeV.
First, we revisit the constraints on decaying and annihilating particle DM. For
DM decaying to two photons, we find that previous limits were overstated by
roughly an order of magnitude. Our new, conservative analysis finds that the DM
lifetime must satisfy $taugtrsim 10^{27},{rm s}times (m_{chi}/rm
MeV)^{-1}$ for DM masses $m_{chi}=0.054-3.6$ MeV. For MeV-scale DM that
annihilates into photons INTEGRAL sets the strongest constraints to date,
whereas for annihilations to electron-positron pairs, INTEGRAL only improves
upon current limits when assuming $p$-wave annihilation. Second, we target
ultralight primordial black holes (PBHs) through their Hawking radiation. This
makes them appear as decaying DM with a photon spectrum peaking at $Eapprox
5/(8pi G M_{rm PBH})$, for a PBH of mass $M_{rm PBH}$. We use the INTEGRAL
data to demonstrate that PBHs with masses less than 2 $times 10^{17}$ g cannot
comprise all of the DM, setting the tightest bound to date on ultralight PBHs.
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has
yielded unprecedented measurements of the soft gamma-ray spectrum of our
Galaxy. Here we use those measurements to set constraints on dark matter (DM)
that decays or annihilates into photons with energies $Eapprox 0.02-2$ MeV.
First, we revisit the constraints on decaying and annihilating particle DM. For
DM decaying to two photons, we find that previous limits were overstated by
roughly an order of magnitude. Our new, conservative analysis finds that the DM
lifetime must satisfy $taugtrsim 10^{27},{rm s}times (m_{chi}/rm
MeV)^{-1}$ for DM masses $m_{chi}=0.054-3.6$ MeV. For MeV-scale DM that
annihilates into photons INTEGRAL sets the strongest constraints to date,
whereas for annihilations to electron-positron pairs, INTEGRAL only improves
upon current limits when assuming $p$-wave annihilation. Second, we target
ultralight primordial black holes (PBHs) through their Hawking radiation. This
makes them appear as decaying DM with a photon spectrum peaking at $Eapprox
5/(8pi G M_{rm PBH})$, for a PBH of mass $M_{rm PBH}$. We use the INTEGRAL
data to demonstrate that PBHs with masses less than 2 $times 10^{17}$ g cannot
comprise all of the DM, setting the tightest bound to date on ultralight PBHs.
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