Ultrafast effective multilevel atom method for primordial hydrogen recombination

Ali-Haı̈moud, Yacine; Hirata, Christopher M.

doi:10.1103/physrevd.82.063521

Cited by 92 publications

(90 citation statements)

References 35 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, initial conditions for the mean ionization fraction x e and for the gas temperature T k are required inputs. We produce these inputs using a modified version of cosmorec/Recfast++ [159][160][161]. 4 The cumulative effect of a population of 100 M PBHs on the global differential 21cm brightness temperature is shown in Fig.…”

Section: Iii11 Global 21cm Line Signalmentioning

confidence: 99%

Constraining the primordial black hole abundance with 21-cm cosmology

et al. 2019

View full text Add to dashboard Cite

The discoveries of a number of binary black hole mergers by LIGO and VIRGO has reinvigorated the interest that primordial black holes (PBHs) of tens of solar masses could contribute non-negligibly to the dark matter energy density. Should even a small population of PBHs with masses O(M ) exist, they could profoundly impact the properties of the intergalactic medium and provide insight into novel processes at work in the early Universe. We demonstrate here that observations of the 21cm transition in neutral hydrogen during the epochs of reionization and cosmic dawn will likely provide one of the most stringent tests of solar mass PBHs. In the context of 21cm cosmology, PBHs give rise to three distinct observable effects: (i) the modification to the primordial power spectrum (and thus also the halo mass function) induced by Poisson noise, (ii) a uniform heating and ionization of the intergalactic medium via X-rays produced during accretion, and (iii) a local modification to the temperature and density of the ambient medium surrounding isolated PBHs. Using a four-parameter astrophysical model, we show that experiments like SKA and HERA could potentially improve upon existing constraints derived using observations of the cosmic microwave background by more than one order of magnitude. I. INTRODUCTIONThe canonical cosmological model assumes that dark matter is comprised of a cold gas of weakly interacting particles. Despite its simplicity, this minimal scenario provides an excellent fit to both cosmic microwave background (CMB) and large-scale structure measurements [1][2][3][4]. However, a precise understanding of the fundamental nature of dark matter is missing and remains at the forefront in the current list of unsolved problems in modern physics.Although dark matter is usually interpreted in terms of a new elementary particle, other alternatives exist. Black holes (BHs) produced prior to big bang nucleosynthesis (BBN), i.e., primordial black holes (PBHs), represent such an alternative -remarkably, this solution is as old as particle dark matter [5]. In particular, this scenario has recently attracted much attention [6][7][8][9][10][11][12] in the context of the LIGO and VIRGO discoveries of several binary BH mergers [13][14][15][16][17].The idea that PBHs could be formed by strong accretion during the radiation-dominated epoch was first introduced five decades ago [18]. It was later suggested that initial fluctuations in the early Universe could give rise to a large number of gravitationally collapsed objects with masses above the Planck mass [19], that however, would not grow substantially by accretion [20]. Very light PBHs would not survive until the present epoch, though; the prediction that any BH should emit particles with a black body spectrum [21,22] implies that PBHs with masses below 10 −18 M (with M the Sun's mass) would have evaporated on cosmological times scales [21][22][23]. While the evaporation of such light PBHs would have interesting observational consequences [24][25][26], only heavier PBHs coul...

show abstract

Section: Iii11 Global 21cm Line Signalmentioning

confidence: 99%

Constraining the primordial black hole abundance with 21-cm cosmology

et al. 2019

View full text Add to dashboard Cite

show abstract

“…We check this explicitly using CosmoRec code [47] to take into account contribution to excitations upto third level for hydrogen and second level of helium by explicitly solving for the excited states without the assumption of effective three level atom. We have used CosmoRec setting with 10 hydrogen and helium interface shells [55], 500 hydrogen levels and all of radiative transfer effects flags turned on. We include contribution from injected energy to excitations from the ground state to 2s, 2p, and 3p levels of hydrogen and 2 1 p level of helium.…”

Section: Effects Of Excitationsmentioning

confidence: 99%

CMB anisotropy and BBN constraints on pre-recombination decay of dark matter to visible particles

Acharya

Khatri

2019

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

Injection of high energy electromagnetic particles around the recombination epoch can modify the standard recombination history and therefore the CMB anisotropy power spectrum. Previous studies have put strong constraints on the amount of electromagnetic energy injection around the recombination era (redshifts z 4500). However, energy injected in the form of energetic (> keV) visible standard model particles is not deposited instantaneously. The considerable delay between the time of energy injection and the time when all energy is deposited to background baryonic gas and CMB photons, together with the extraordinary precision with which the CMB anisotropies have been measured, means that CMB anisotropies are sensitive to energy that was injected much before the epoch of recombination. We show that the CMB anisotropy power spectrum is sensitive to energy injection even at z = 10000, giving stronger constraints compared to big bang nucleosynthesis and CMB spectral distortions. We derive, using Planck CMB data, the constraints on long-lived unstable particles decaying at redshifts z 10000 (lifetime τ X 10 11 s) by explicitly evolving the electromagnetic cascades in the expanding Universe, thus extending previous constraints to lower particle lifetimes. We also revisit the BBN constraints and show that the delayed injection of energy is important for BBN constraints. We find that the constraints can be weaker by a factor of few to almost an order of magnitude, depending on the energy, when we relax the quasi-static or on-the-spot assumptions.

show abstract

“…[14][15][16][17] and references therein). The tails of the visibility function are less important, but an accuracy of about 1 percent is still needed, which required implementing an accurate multilevel-atom formulation of the recombination problem [18][19][20][21]. Such a high sensitivity to the recombination history can be turned into an asset and serve to probe unusual physics taking place during the recombination history as, for example, the presence of primordial heavy elements.…”

Section: Introductionmentioning

confidence: 99%

Metals at the surface of last scatter

2011

Self Cite

View full text Add to dashboard Cite

Standard big-bang nucleosynthesis (BBN) predicts only a trace abundance of lithium and no heavier elements, but some alternatives predict a nonzero primordial metallicity. Here we explore whether CMB measurements may set useful constraints to the primordial metallicity and/or whether the standard CMB calculations are robust, within the tolerance of forthcoming CMB maps, to the possibility of primordial metals. Metals would affect the recombination history (and thus CMB power spectra) in three ways: (1) Ly photons can be removed (and recombination thus accelerated) by photoionizing metals; (2) The Bowen resonance-fluorescence mechanism may degrade Ly photons and thus enhance the Ly escape probability and speed up recombination; (3) Metals could affect the low-redshift tail of the CMB visibility function by providing additional free electrons. The last two of these provide the strongest CMB signal. However, the effects are detectable in the Planck satellite only if the primordial metal abundance is at least a few hundredths of solar for (2) and a few tenths of solar for (3). We thus conclude that Planck will not be able to improve upon current constraints to primordial metallicity, at the level of a thousandth of solar, from the Lyman-forest and ultra-metal-poor halo stars, and that the CMB power-spectrum predictions for Planck suffer no uncertainty arising from the possibility that there may be primordial metals.

show abstract

Ultrafast effective multilevel atom method for primordial hydrogen recombination

Cited by 92 publications

References 35 publications

Constraining the primordial black hole abundance with 21-cm cosmology

Constraining the primordial black hole abundance with 21-cm cosmology

CMB anisotropy and BBN constraints on pre-recombination decay of dark matter to visible particles

Metals at the surface of last scatter

Contact Info

Product

Resources

About