Ubiquitous seeding of supermassive black holes by direct collapse

By Bhaskar Agarwal, S. Khochfar, Jarrett L. Johnson, E. Neistein, Claudio Dalla Vecchia, M. Livio. 2012

209 citations recorded by the source corpus.

We study for the first time the environment of massive black hole (BH) seeds (∼10 4−5 M� ) formed via the direct collapse of pristine gas clouds in massive haloes (≥10 7 M� )a tz > 6. Our model is based on the evolution of dark matter haloes within a cosmological N-body simulation, combined with prescriptions for the formation of BH along with both Population III (Pop III) and Population II (Pop II) stars. We calculate the spatially varying intensity of Lyman–Werner (LW) radiation from stars and identify the massive pristine haloes in which it is high enough to shut down molecular hydrogen cooling. In contrast to previous BH seeding models with a spatially constant LW background, we find that the intensity of LW radiation due to local sources, Jlocal, can be up to ∼10 6 times the spatially averaged background in the simulated volume and exceeds the critical value, Jcrit, for the complete suppression of molecular cooling, in some cases by four orders of magnitude. Even after accounting for possible metal pollution in a halo from previous episodes of star formation, we find a steady rise in the formation rate of direct collapse BHs (DCBHs) with decreasing redshift from 10 −3 Mpc −3 z −1 at z = 12 to 10 −2 Mpc −3 z −1 at z = 6. The onset of Pop II star formation at z ≈ 16 simultaneously marks the onset of the epoch of DCBH formation, as the increased level of LW radiation from Pop II stars is able to elevate the local levels of the LW intensity to Jlocal > Jcrit, while Pop III stars fail to do so at any time. The number density of DCBHs is sensitive to the number of LW photons and can vary by over an order of magnitude at z = 7 after accounting for reionization feedback. Haloes hosting DCBHs are more clustered than similar massive counterparts that do not host DCBHs, especially at redshifts z 10. Also, the DCBHs that form at z > 10 are found to reside in highly clustered regions, whereas the DCBHs formed around z ∼ 6a re more common. We also show that planned surveys with James Webb Space Telescope should be able to detect the supermassive stellar precursors of DCBHs.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b2b54ee67f846988a0d239a0c711d5c6cfe765f0

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Citations in the corpus

Primordial black holes as generators of cosmic structures (2018, background): “Both of these have been explored in a series of papers by Agarwal et al. (2012, 2013, 2014, 2016) but they are not without difficulties.”
The First Billion Years project: the impact of stellar radiation on the co-evolution of Populations II and III (2012, background): “This result corroborates other recent work (e.g. Agarwal et al. 2012) in supporting the theory that these sites may play host to the formation of the supermassive (> ∼ 104 M⊙) stellar seeds of the black holes inhabiting the centres of galaxies today.”
Black hole formation in the early Universe (2013, background): “The abundance of such haloes was previously calculated by Dijkstra et al. (2008) and Agarwal et al. (2012), showing that these are indeed frequent enough to explain the number of observed high-redshift black holes.”
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution (2015, background): “15 (e.g., Agarwal et al. 2012).”
Modeling the Radio Background from the First Black Holes at Cosmic Dawn: Implications for the 21 cm Absorption Amplitude (2018, methodology): “Dijkstra et al. (2014) predicted an occurrence rate of ~ - - -– h10 10 Mpc7 5 3 3 at z=10, while Agarwal et al. (2012) predicted significantly higher values of ~ - -h10 Mpc3 3 3.”
Titans of the early Universe: The Prato statement on the origin of the first supermassive black holes (2018, methodology): “This can be particularly attributed to the lower Jcrit = 30 (Agarwal et al. 2012, 2014) which in turn suggests that the DCBH scenario may be able to seed the SMBHs of more normal galaxies.”
Formation of Supermassive Black Hole Seeds (2016, background): “As we discuss in the next subsections that constraint of a strong LW fluxes requires that DCBH hosting halo should form in the vicinity (about few kpc) of a massive star forming galaxy (Dijkstra et al. 2008; Agarwal et al. 2012; Habouzit et al. 2016b).”
ONE HUNDRED FIRST STARS: PROTOSTELLAR EVOLUTION AND THE FINAL MASSES (2013, background): “…Pop III.2 stars, which are formed in a primordial gas that has been affected by the prior existence of other stars (both the Pop III and Pop II stars; the latter can contribute orders of magnitude more strongly, in particular, at low redshifts, z < 15, as shown in Figure 6 of Agarwal et al. 2012) .”
Observational evidence for intermediate-mass black holes (2017, background): “…collapse can only occur in halos close (within 15 kpc) to luminous star-forming galaxies producing sufficient Lyman-Werner ra- diation (e.g., Dijkstra et al. 2014, 2008; Agarwal et al. 2014, 2012; Habouzit et al. 2016) and is thus thought to be a much less common mechanism of IMBH forma- tion.”
FORMATION OF PRIMORDIAL SUPERMASSIVE STARS BY RAPID MASS ACCRETION (2013, background): “…H2 formation have been proposed, e.g., photodissociation by strong UV background (Omukai 2001; Oh & Haiman 2002; Wise et al. 2008; Shang et al. 2010; Wolcott-Green et al. 2011; Inayoshi & Omukai 2011; Agarwal et al. 2012), and collisional dissociation in dense shocks (Inayoshi & Omukai 2012).”