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arXiv · 1812.07967

Multi-wavelength astronomical searches for primordial black holes

Julien Manshanden·Daniele Gaggero·Gianfranco Bertone·Riley M. T. Connors·Massimo Ricotti
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Abstract

If primordial black holes of $\mathcal{O}(1-100) M_{\odot}$ constitute a significant portion of the dark matter in the Universe, they should be very abundant in our Galaxy. We present here a detailed analysis of the radio and X-ray emission that these objects are expected to produce due to the accretion of gas from the interstellar medium. With respect to previous studies, we relax the assumption of a monochromatic mass function, and introduce an improved treatment of the physics of gas accretion onto isolated, moving compact objects, based on a set of state-of-the-art numerical simulations. By comparing our predictions with known radio and X-ray sources in the Galactic center region, we show that the maximum relic density of primordial black holes in the mass range of interest is $\sim 10^{-3}$ smaller than that of dark matter. The new upper bound is two orders of magnitude stronger with respect to previous results, based on a conservative phenomenological treatment of the accretion physics. We also provide a comprehensive critical discussion on the reliability of this bound, and on possible future developments in the field. We argue in particular that future multi-wavelength searches will soon start to probe the galactic population of astrophysical black holes.

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Julien Manshanden, Daniele Gaggero, Gianfranco Bertone, Riley M. T. Connors, Massimo Ricotti. 2019-07-02. Multi-wavelength astronomical searches for primordial black holes. https://doi.org/10.1088/1475-7516%2F2019%2F06%2F026

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