scholarly journals Looking for MACHOs in the spectra of fast radio bursts

2020 ◽  
Vol 496 (1) ◽  
pp. 564-580 ◽  
Author(s):  
Andrey Katz ◽  
Joachim Kopp ◽  
Sergey Sibiryakov ◽  
Wei Xue
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Gamma Ray ◽  
Mass Range ◽  
Host Galaxy ◽  
Primordial Black Holes ◽  
Radio Bursts ◽  
Interstellar Scintillation ◽  
Massive Compact Halo Objects ◽  
Main Complication

ABSTRACT We explore a novel search strategy for dark matter in the form of massive compact halo objects (MACHOs) such as primordial black holes or dense mini-haloes in the mass range from $10^{-4}\, \mathrm{M}_{\odot }$ to $0.1\, \mathrm{M}_{\odot }$. These objects can gravitationally lens the signal of fast radio bursts (FRBs), producing a characteristic interference pattern in the frequency spectrum, similar to the previously studied femtolensing signal in gamma-ray burst spectra. Unlike traditional searches using microlensing, FRB lensing will probe the abundance of MACHOs at cosmological distance scales (∼Gpc) rather than just their distribution in the neighbourhood of the Milky Way. The method is thus particularly relevant for dark mini-haloes, which may be inaccessible to microlensing due to their finite spatial extent or tidal disruption in galaxies. We find that the main complication in FRB lensing will be interstellar scintillation in the FRB’s host galaxy and in the Milky Way. Scintillation is difficult to quantify because it heavily depends on turbulence in the interstellar medium, which is poorly understood. We show that, nevertheless, for realistic scintillation parameters, FRB lensing can set competitive limits on compact dark matter object, and we back our findings with explicit simulations.

scholarly journals Constraints on stupendously large black holes

2020 ◽  
Vol 501 (2) ◽  
pp. 2029-2043
Author(s):  
Bernard Carr ◽  
Florian Kühnel ◽  
Luca Visinelli
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gamma Ray ◽  
Background Radiation ◽  
Galactic Nuclei ◽  
Mass Range ◽  
Weakly Interacting Massive Particles ◽  
Observational Constraints ◽  
Primordial Black Holes ◽  
Massive Particles

ABSTRACT We consider the observational constraints on stupendously large black holes (SLABs) in the mass range $M \gtrsim 10^{11}\, \mathrm{ M_{\odot}}$. These have attracted little attention hitherto, and we are aware of no published constraints on a SLAB population in the range (1012–$10^{18})\, \mathrm{ M_{\odot}}$. However, there is already evidence for black holes of up to nearly $10^{11}\, \mathrm{ M_{\odot}}$ in galactic nuclei, so it is conceivable that SLABs exist and they may even have been seeded by primordial black holes. We focus on limits associated with (i) dynamical and lensing effects, (ii) the generation of background radiation through the accretion of gas during the pre-galactic epoch, and (iii) the gamma-ray emission from the annihilation of the halo of weakly interacting massive particles expected to form around each SLAB if these provide the dark matter. Finally, we comment on the constraints on the mass of ultralight bosons from future measurements of the mass and spin of SLABs.

scholarly journals Quantifying tidal stream disruption in a simulated Milky Way

2017 ◽  
Vol 470 (1) ◽  
pp. 522-538 ◽  
Author(s):  
Emily Sandford ◽  
Andreas H. W. Küpper ◽  
Kathryn V. Johnston ◽  
Jürg Diemand
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Galactic Halo ◽  
Mass Range ◽  
Galactic Centre ◽  
High Dimensions ◽  
Density Profiles ◽  
Upper Limits ◽  
Tidal Stream ◽  
Tidal Streams

Abstract Simulations of tidal streams show that close encounters with dark matter subhaloes induce density gaps and distortions in on-sky path along the streams. Accordingly, observing disrupted streams in the Galactic halo would substantiate the hypothesis that dark matter substructure exists there, while in contrast, observing collimated streams with smoothly varying density profiles would place strong upper limits on the number density and mass spectrum of subhaloes. Here, we examine several measures of stellar stream ‘disruption' and their power to distinguish between halo potentials with and without substructure and with different global shapes. We create and evolve a population of 1280 streams on a range of orbits in the Via Lactea II simulation of a Milky Way-like halo, replete with a full mass range of Λcold dark matter subhaloes, and compare it to two control stream populations evolved in smooth spherical and smooth triaxial potentials, respectively. We find that the number of gaps observed in a stellar stream is a poor indicator of the halo potential, but that (i) the thinness of the stream on-sky, (ii) the symmetry of the leading and trailing tails and (iii) the deviation of the tails from a low-order polynomial path on-sky (‘path regularity') distinguish between the three potentials more effectively. We furthermore find that globular cluster streams on low-eccentricity orbits far from the galactic centre (apocentric radius ∼30–80 kpc) are most powerful in distinguishing between the three potentials. If they exist, such streams will shortly be discoverable and mapped in high dimensions with near-future photometric and spectroscopic surveys.

scholarly journals The characterization of the gamma-ray signal from the central Milky Way: A case for annihilating dark matter

2016 ◽  
Vol 12 ◽  
pp. 1-23 ◽  
Author(s):  
Tansu Daylan ◽  
Douglas P. Finkbeiner ◽  
Dan Hooper ◽  
Tim Linden ◽  
Stephen K.N. Portillo ◽  
...  
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Gamma Ray

scholarly journals Analysis of the very inner Milky Way dark matter distribution and gamma-ray signals

2016 ◽  
Vol 94 (12) ◽  
Author(s):  
V. Gammaldi ◽  
V. Avila-Reese ◽  
O. Valenzuela ◽  
A. X. Gonzalez-Morales
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Gamma Ray ◽  
Matter Distribution ◽  
Dark Matter Distribution

scholarly journals The dark matter interpretation of the 3.5-keV line is inconsistent with blank-sky observations

Science ◽  
2020 ◽  
Vol 367 (6485) ◽  
pp. 1465-1467 ◽  
Author(s):  
Christopher Dessert ◽  
Nicholas L. Rodd ◽  
Benjamin R. Safdi
Keyword(s):  
Dark Matter ◽  
Emission Line ◽  
Decay Rate ◽  
Milky Way ◽  
Line Emission ◽  
Mass Range ◽  
Sterile Neutrinos ◽  
X Ray ◽  
Upper Limit ◽  
Nearby Galaxies

Observations of nearby galaxies and galaxy clusters have reported an unexpected x-ray emission line around 3.5 kilo–electron volts (keV). Proposals to explain this line include decaying dark matter—in particular, that the decay of sterile neutrinos with a mass around 7 keV could match the available data. If this interpretation is correct, the 3.5-keV line should also be emitted by dark matter in the halo of the Milky Way. We used more than 30 megaseconds of XMM-Newton (X-ray Multi-Mirror Mission) blank-sky observations to test this hypothesis, finding no evidence of the 3.5-keV line emission from the Milky Way halo. We set an upper limit on the decay rate of dark matter in this mass range, which is inconsistent with the possibility that the 3.5-keV line originates from dark matter decay.

Primordial black holes and the observable features of the universe

2015 ◽  
Vol 24 (13) ◽  
pp. 1545005 ◽  
Author(s):  
K. M. Belotsky ◽  
A. A. Kirillov ◽  
S. G. Rubin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Galactic Center ◽  
Mass Range ◽  
Primordial Black Holes ◽  
Simultaneous Solution ◽  
Supermassive Black Hole ◽  
Range Distribution ◽  
The Universe

Here, we briefly discuss the possibility to solve simultaneously with primordial black holes (PBHs) the problems of dark matter (DM), reionization of the universe, origin of positron line from Galactic center and supermassive black hole (BH) in it. Discussed scenario can naturally lead to a multiple-peak broad-mass-range distribution of PBHs in mass, which is necessary for simultaneous solution of the problems.

scholarly journals Understanding the diffuse gamma ray emission of the milky way - from supernova remnants to dark matter

2019 ◽  
pp. 17-22
Author(s):  
Jovana Petrovic ◽  
Tijana Prodanovic ◽  
Milos Kovacevic
Keyword(s):  
Dark Matter ◽  
Supernova Remnants ◽  
Milky Way ◽  
Gamma Ray ◽  
Galactic Center ◽  
Galactic Disk ◽  
High Energy ◽  
Data Sets ◽  
Source Population ◽  
Gamma Ray Emission

Diffuse gamma ray emission from the Galactic center at 2-3 GeV, as well as the 12 TeV gamma ray excess in the Galactic disk, remain open for debate and represent the missing puzzles in the complete picture of the high-energy Milky Way sky. Our papers emphasize the importance of understanding all of the populations that contribute to the diffuse gamma background in order to discriminate between the astrophysical sources such as supernova remnants and pulsars, and something that is expected to be seen in gamma rays and is much more exotic - dark matter. We analyze two separate data sets that have been measured in different energy ranges from the ?Fermi-LAT? and ?Milagro? telescopes, using these as a powerful tool to limit and test our analytical source population models. We model supernova remnants and pulsars, estimating the number of still undetected ones that contribute to the diffuse background, trying to explain both the Galactic center and the 12 TeV excess. Furthermore, we aim to predict the number of soon to be detected sources with new telescopes, such as the ?HAWC?.

scholarly journals Relieving Tensions Related to the Dark Matter Interpretation of the Fermi-LAT Data

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 92
Author(s):  
Man Chan
Keyword(s):  
Dark Matter ◽  
Synchrotron Radiation ◽  
Milky Way ◽  
Gamma Ray ◽  
Feedback Process ◽  
Dark Matter Annihilation ◽  
Dwarf Spheroidal Galaxies ◽  
Matter Model ◽  
Consistent Picture ◽  
Dark Matter Model

Recently, many studies indicate that the GeV gamma ray excess signal from the central Milky Way can be best explained by ∼40–50 GeV dark matter annihilating via the b b ¯ channel. However, this model appears to be disfavored by the recent Fermi-LAT data for dwarf spheroidal galaxies and the constraint from synchrotron radiation. In this article, we describe a consistent picture to relieve the tensions between the dark matter annihilation model and the observations. We show that a baryonic feedback process is the key to alleviate the tensions and the ∼40–50 GeV dark matter model is still the best one to account for the GeV gamma ray excess in the Milky Way.

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