21 cm limits on decaying dark matter and primordial black holes

Clark, Steven J.; Dutta, Bhaskar; Gao, Y.; Ma, Yin‐Zhe; Strigari, Louis E.

doi:10.1103/physrevd.98.043006

Cited by 134 publications

(183 citation statements)

References 72 publications

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“…In particular, the authors of [57,58] set decay lifetime limits in a similar manner as [34], assuming an absorption signal that is smaller than the EDGES signal, with either T 21 ¼ 100 mK or 50 mK. We reiterate that these limits are equivalent to our additional 21-cm source limits, with ðT S =T R Þ obs ¼ 0.26 and 0.41, respectively, and setting T R ¼ T CMB at z ¼ 17.2.…”

Section: Resultsmentioning

confidence: 99%

“…Simultaneous with and slightly after the release of this work, several other authors also studied the sensitivity of 21-cm measurements to DM annihilation or decays [56][57][58]. In particular, the authors of [57,58] set decay lifetime limits in a similar manner as [34], assuming an absorption signal that is smaller than the EDGES signal, with either T 21 ¼ 100 mK or 50 mK.…”

Section: Resultsmentioning

confidence: 99%

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Implications of a 21-cm signal for dark matter annihilation and decay

2018

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Measurements of the temperature of the baryons at the end of the cosmic dark ages can potentially set very precise constraints on energy injection from exotic sources, such as annihilation or decay of the dark matter. However, additional effects that lower the gas temperature can substantially weaken the expected constraints on exotic energy injection, whereas additional radiation backgrounds can conceal the effect of an increased gas temperature in measurements of the 21-cm hyperfine transition of neutral hydrogen. Motivated in part by recent claims of a detection of 21-cm absorption from z ∼ 17 by the EDGES experiment, we derive the constraints on dark matter annihilation and decay that can be placed in the presence of extra radiation backgrounds or effects that modify the gas temperature, such as DM-baryon scattering and early baryon-photon decoupling. We find that if the EDGES observation is confirmed, then constraints on light DM decaying or annihilating to electrons will in most scenarios be stronger than existing state-of-the-art limits from the cosmic microwave background, potentially by several orders of magnitude. More generally, our results allow mapping any future measurement of the global 21-cm signal into constraints on dark matter annihilation and decay, within the broad range of scenarios we consider.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Implications of a 21-cm signal for dark matter annihilation and decay

2018

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“…The 21-cm spectrum, therefore, constitutes a new and important cosmological observable able to probe the properties of PBHs with a reach comparable to, if not exceeding, that of the constraints previously considered in the literature. Note added.-Simultaneously to our paper, a complementary work [64] appeared, where the EDGES 21-cm observations were used to put constraints on evaporating PBHs.…”

Section: Resultsmentioning

confidence: 99%

Constraining primordial black holes with the EDGES 21-cm absorption signal

et al. 2018

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The EDGES experiment has recently measured an anomalous global 21-cm spectrum due to hydrogen absorptions at redshifts of about z ∼ 17. Model independently, the unusually low temperature of baryons probed by this observable sets strong constraints on any physical process that transfers energy into the baryonic environment at such redshifts. Here, we make use of the 21-cm spectrum to derive bounds on the energy injection due to a possible population of Oð1-100ÞM ⊙ primordial black holes, which induce a wide spectrum of radiation during the accretion of the surrounding gas. After calculating the total radiative intensity of a primordial black hole population, we estimate the amount of heat and ionizations produced in the baryonic gas and compute the resulting thermal history of the Universe with a modified version of RECFAST code. Finally, by imposing that the temperature of the gas at z ∼ 17 does not exceed the indications of EDGES, we constrain the possible abundance of primordial black holes. Depending on uncertainties related to the accretion model, we find that Oð10ÞM ⊙ primordial black holes can only contribute to a fraction f PBH < ð1-10 −3 Þ of the total dark matter abundance.

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“…elec_cooling contains the code necessary to compute the transfer functions R c , T ICS and T e , as defined in Eqs. (13), (16) and (17) respectively; Example 6 shows how this module is used.…”

Section: E Darkhistoryelectronsmentioning

confidence: 99%

Code package for calculating modified cosmic ionization and thermal histories with dark matter and other exotic energy injections

2020

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We present a new public Python package, DarkHistory, for computing the effects of dark matter annihilation and decay on the temperature and ionization history of the early universe. DarkHistory simultaneously solves for the evolution of the free electron fraction and gas temperature, and for the cooling of annihilation/decay products and the secondary particles produced in the process. Consequently, we can self-consistently include the effects of both astrophysical and exotic sources of heating and ionization, and automatically take into account backreaction, where modifications to the ionization/temperature history in turn modify the energy-loss processes for injected particles. We present a number of worked examples, demonstrating how to use the code in a range of different configurations, in particular for arbitrary dark matter masses and annihilation/decay final states. Possible applications of DarkHistory include mapping out the effects of dark matter annihilation/decay on the global 21cm signal and the epoch of reionization, as well as the effects of exotic energy injections other than dark matter annihilation/decay. The code is available at https://github.com/hongwanliu/DarkHistory with documentation at https://darkhistory.readthedocs.io. Data files required to run the code can be downloaded at https://doi.org/10.7910/DVN/DUOUWA. arXiv:1904.09296v1 [astro-ph.CO] 19 Apr 2019 1 We follow the standard astrophysical convention in which H and H + are denoted HI and HII, while He, He + and He 2+ are denoted HeI, HeII and HeIII respectively. 2 The value of β H used in DarkHistory includes the constant and gaussian fudge factors used by version 1.5.2 of RECFAST.

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21 cm limits on decaying dark matter and primordial black holes

Cited by 134 publications

References 72 publications

Implications of a 21-cm signal for dark matter annihilation and decay

Implications of a 21-cm signal for dark matter annihilation and decay

Constraining primordial black holes with the EDGES 21-cm absorption signal

Code package for calculating modified cosmic ionization and thermal histories with dark matter and other exotic energy injections

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