Evolution of Intergalactic Gas in the Neighborhood of Dwarf Galaxies and Its Manifestations in the HI 21 cm Line

Vasiliev, E. O.; Ryabova, M. V.; Shchekinov, Yu. A.; Sethi, Shiv K.

doi:10.1134/s1990341318040028

Cited by 3 publications

(2 citation statements)

References 43 publications

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“…It is seen that the star formation may compete with the accreting BH in the generation of X-ray photons only for an exceptionally high SFR∼ 10 3 -10 6 M⊙ yr −1 . It allows us to conclude that the contribution of stellar sources to the X-ray radiation in the IGM surrounding a grow BH is expected to be negligible (for details on the contribution of stellar sources see Vasiliev et al 2018a). We could also address the following question: what is the impact of distant sources on the ionization state of Helium surrounding an accreting BH.…”

Section: The Ionized Igm Around Bhmentioning

confidence: 99%

Probing primordial 3He from hyperfine line afterglows around supercritical black holes

Vasiliev

Sethi

Shchekinov

2019

Monthly Notices of the Royal Astronomical Society

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We consider the possibility of the detection of 3 HeII hyperfine line (rest frequency, 8.67 GHz) emission from ionized zones around accreting black holes (BHs) formed at high redshifts, z = 15-30. We show that the brightness temperature in 8.67GHz line increases and reaches a peak value after the accretion onto the BH exhausts and HeIII recombines into HeII. This period of brightening last up to 40 million years. We find that during this period the maximum brightness temperature reaches ≃ 0.2-0.5µK, depending on the epoch when such a black hole starts growing. The maximum angular size of the region emitting in the hyperfine line is around 0.5 ′ . The flux from such a region (≃ 0.3 nJy) is too small to be detected by SKA1-MID. The RMS of the collective flux from many emitting regions from a volume bounded by the synthesized beam and the band-width of SKA1-MID might reach 100 nJy, which is potentially detectable by SKA1-MID.

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Section: The Ionized Igm Around Bhmentioning

confidence: 99%

Probing primordial 3He from hyperfine line afterglows around supercritical black holes

Vasiliev

Sethi

Shchekinov

2019

Monthly Notices of the Royal Astronomical Society

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“…Its softer spectrum potentially likens its signatures to those of the more exotic cosmic rays (e.g. Sazonov & Sunyaev 2015;Leite et al 2017;Jana & Nath 2018) and AGB stars (Vasiliev et al 2018). Finally, high-and low-mass X-ray binaries (XRBs) may also play a role.…”

Section: Introductionmentioning

confidence: 98%

Large scale simulations of H and He reionization and heating driven by stars and more energetic sources

Eide,

Ciardi,

Graziani

et al. 2020

Preprint

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We present simulations of cosmic reionization and reheating from z = 18 to z = 5, investigating the role of stars (emitting soft UV-photons), nuclear black holes (BHs, with power-law spectra), X-ray binaries (XRBs, with hard X-ray dominated spectra), and the supernova-associated thermal bremsstrahlung of the diffuse interstellar medium (ISM, with soft X-ray spectra). We postprocess the hydrodynamical simulation Massive-Black II (MBII) with multifrequency ionizing radiative transfer. The source properties are directly derived from the physical environment of MBII, and our only real free parameter is the ionizing escape fraction f esc . We find that, among the models explored here, the one with an escape fraction that decreases with decreasing redshift yields results most in line with observations, such as of the neutral hydrogen fraction and the Thomson scattering optical depth. Stars are the main driver of hydrogen reionization and consequently of the thermal history of the intergalactic medium (IGM). We obtain x HII = 0.99998 at z = 6 for all source types, with volume averaged temperatures T ∼ 20, 000 K. BHs are rare and negligible to hydrogen reionization, but conversely they are the only sources which can fully ionize helium, increasing local temperatures by ∼ 10 4 K. The thermal and ionization state of the neutral and lowly ionized hydrogen differs significantly with different source combinations, with ISM and (to a lesser extent) XRBs, playing a significant role and, as a consequence, determining the transition from absorption to emission of the 21 cm signal from neutral hydrogen.

show abstract

Large-scale simulations of H and He reionization and heating driven by stars and more energetic sources

Eide

Ciardi

Graziani

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present simulations of cosmic reionization and reheating from z = 18 to z = 5, investigating the role of stars (emitting soft UV-photons), nuclear black holes (BHs, with power-law spectra), X-ray binaries (XRBs, with hard X-ray dominated spectra), and the supernova-associated thermal bremsstrahlung of the diffuse interstellar medium (ISM, with soft X-ray spectra). We post-process the hydrodynamical simulation Massive-Black II (MBII) with multifrequency ionizing radiative transfer. The source properties are directly derived from the physical environment of MBII, and our only real free parameter is the ionizing escape fraction fesc. We find that, among the models explored here, the one with an escape fraction that decreases with decreasing redshift yields results most in line with observations, such as of the neutral hydrogen fraction and the Thomson scattering optical depth. Stars are the main driver of hydrogen reionization and consequently of the thermal history of the intergalactic medium (IGM). We obtain 〈xHslowromancapii@〉 = 0.99998 at z = 6 for all source types, with volume averaged temperatures 〈 T〉 ∼ 20, 000 K. BHs are rare and negligible to hydrogen reionization, but conversely they are the only sources which can fully ionize helium, increasing local temperatures by ∼104 K. The thermal and ionization state of the neutral and lowly ionized hydrogen differs significantly with different source combinations, with ISM and (to a lesser extent) XRBs, playing a significant role and, as a consequence, determining the transition from absorption to emission of the 21 cm signal from neutral hydrogen.

show abstract

Evolution of Intergalactic Gas in the Neighborhood of Dwarf Galaxies and Its Manifestations in the HI 21 cm Line

Cited by 3 publications

References 43 publications

Probing primordial 3He from hyperfine line afterglows around supercritical black holes

Probing primordial 3He from hyperfine line afterglows around supercritical black holes

Large scale simulations of H and He reionization and heating driven by stars and more energetic sources

Large-scale simulations of H and He reionization and heating driven by stars and more energetic sources

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