%0 Generic %1 eide2020mocking %A Eide, Marius B. %A Ciardi, Benedetta %A Feng, Yu %A Di Matteo, Tiziana %D 2020 %K library %T Mocking Faint Black Holes during Reionization %U http://arxiv.org/abs/2010.09722 %X To investigate the potential abundance and impact of nuclear black holes (BHs) during reionization, we generate a neural network that estimates their masses and accretion rates by training it on 23 properties of galaxies harbouring them at $z=6$ in the cosmological hydrodynamical simulation Massive-Black II. We then populate all galaxies in the simulation from $z=18$ to $z=5$ with BHs from this network. As the network allows to robustly extrapolate to BH masses below those of the BH seeds, we predict a population of faint BHs with a turnover-free luminosity function, while retaining the bright (and observed) BHs, and together they predict a Universe in which intergalactic hydrogen is $15\%$ ionized at $z=6$ for a clumping factor of 5. Faint BHs may play a stronger role in H reionization without violating any observational constraints. This is expected to have an impact also on pre-heating and -ionization, which is relevant to observations of the 21 cm line from neutral H. We also find that BHs grow more efficiently at higher $z$, but mainly follow a redshift-independent galaxy-BH relation. We provide a power law parametrisation of the hydrogen ionizing emissivity of BHs.

@misc{eide2020mocking, abstract = {To investigate the potential abundance and impact of nuclear black holes (BHs) during reionization, we generate a neural network that estimates their masses and accretion rates by training it on 23 properties of galaxies harbouring them at $z=6$ in the cosmological hydrodynamical simulation Massive-Black II. We then populate all galaxies in the simulation from $z=18$ to $z=5$ with BHs from this network. As the network allows to robustly extrapolate to BH masses below those of the BH seeds, we predict a population of faint BHs with a turnover-free luminosity function, while retaining the bright (and observed) BHs, and together they predict a Universe in which intergalactic hydrogen is $15\%$ ionized at $z=6$ for a clumping factor of 5. Faint BHs may play a stronger role in H reionization without violating any observational constraints. This is expected to have an impact also on pre-heating and -ionization, which is relevant to observations of the 21 cm line from neutral H. We also find that BHs grow more efficiently at higher $z$, but mainly follow a redshift-independent galaxy-BH relation. We provide a power law parametrisation of the hydrogen ionizing emissivity of BHs.}, added-at = {2020-10-21T08:55:18.000+0200}, author = {Eide, Marius B. and Ciardi, Benedetta and Feng, Yu and Di Matteo, Tiziana}, biburl = {https://www.bibsonomy.org/bibtex/244867c4f39f273cbe84a42a4c0871714/gpkulkarni}, description = {Mocking Faint Black Holes during Reionization}, interhash = {ad5f0ff601a28ec75701b75dfe27384b}, intrahash = {44867c4f39f273cbe84a42a4c0871714}, keywords = {library}, note = {cite arxiv:2010.09722Comment: 8 pages, 7 figures, accepted for publication in MNRAS}, timestamp = {2020-10-21T08:55:18.000+0200}, title = {Mocking Faint Black Holes during Reionization}, url = {http://arxiv.org/abs/2010.09722}, year = 2020 }