High Redshift Quasars, Emission Lines and ‘Cloudy’

Ferland, Gary J.

doi:10.1515/astro-2017-0307

Cited by 6 publications

(7 citation statements)

References 24 publications

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“…The radiative transfer routines we employ in post-processing are best described by Barrow et al (2018) 23 . In summary, we calculate opacities and emissivities for gas, metals, and dust over the range of temperatures in our simulation and the range of wavelengths in our spectral modelling using CLOUDY 54 . Then we use these profiles to run a Monte Carlo photon calculation using HYPERION 55 .…”

Section: Methodsmentioning

confidence: 99%

Observational signatures of massive black hole formation in the early Universe

2018

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We study a simulation of a nascent massive, so-called direct-collapse, black hole that induces a wave of nearby massive metal-free star formation, unique to this seeding scenario and to very high redshifts. We implement a dynamic, fully-three dimensional prescription for black hole radiative feedback, star formation, and radiative transfer to explore the observational signatures of the massive black hole hosting galaxy. We find a series of distinct colors and emission line strengths, dependent on the relative strength of star formation and black hole accretion. We predict that the forthcoming James Webb Space Telescope might be able to detect and distinguish a young galaxy that hosts a direct-collapse black hole in this configuration at redshift 15 with as little as a 20,000-second total exposure time across four filters, critical for constraining supermassive black hole seeding mechanisms and early growth rates. We also find that a massive seed black hole produces strong, H 2 -dissociating Lyman-Werner radiation. 1 arXiv:1809.03526v1 [astro-ph.GA] 10 Sep 2018The existence of quasars when the Universe was less than a billion years old 1-5 implies that their progenitors are seeded at very early times and grow rapidly. However, black hole growth rates 6,7 are limited by their own radiation feedback, requiring models to either demonstrate high accretion rates or a massive black hole seed 8,9 . In the presense of a Lyman-Werner (LW; 11.2 -13.6 eV) background, the formation of molecular hydrogen (H 2 ) in a primordial, star-less halo is suppressed and the gas can only cool atomically 10, 11 . After reaching a virial temperature of ∼ 10 4 K, these "atomic cooling" halos collapse isothermally to hydrogen number densities of 10 6 cm −3 without fragmenting 12 . After which, the gas becomes optically thick to Ly-α, and we expect the medium to begin a runaway collapse that eventually leads to the formation of a massive (10 3 − 10 5 M ) direct collapse black hole (DCBH) [13][14][15] .We simulate the evolution of a DCBH-hosting halo using the radiation hydrodynamics ENZO 16 code. In our simulation, star formation is suppressed by the dissociation of molecular hydrogen (H 2 ) due to an isotropic, strong (10 3 J 21 * ), and constant LW background, which we apply from z = 30 until the end of the simulation. Prior to the introduction of the black hole at z = 15, our host halo has a virial temperature of ∼ 10 4 K, is hydrodynamically collapsing, is metal-free, and hosts no prior star formation, which is physically conincident with the conditions preceeding DCBH formation. Chon et al. (2016) 17 suggest a peak in the frequency of DCBH formation around z ≈ 15 and we focus on this value for our analysis in light of observational evidence of * J 21 ≡ 10 −21 erg s −1 cm −2 Hz −1 sr −1

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Section: Methodsmentioning

confidence: 99%

Observational signatures of massive black hole formation in the early Universe

2018

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“…The baryonic physics implemented into GIZMO are developed based on extensive tests studying idealised simulations of both isolated disks and galaxy mergers [39][40][41][42][43][44] . The gas cools utilising an updated cooling curve to standard 45 implementations in SPH codes which includes both atomic and molecular line emission 46 . The modeled interstellar medium is multiphase.…”

Section: Cosmological Hydrodynamic Zoom Simulationsmentioning

confidence: 99%

The formation of submillimetre-bright galaxies from gas infall over a billion years

Narayanan

Turk

Feldmann

et al. 2015

Nature

205

221

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Submillimetre-bright galaxies at high redshift are the most luminous, heavily star-forming galaxies in the Universe and are characterized by prodigious emission in the far-infrared, with a flux of at least five millijanskys at a wavelength of 850 micrometres. They reside in haloes with masses about 10(13) times that of the Sun, have low gas fractions compared to main-sequence disks at a comparable redshift, trace complex environments and are not easily observable at optical wavelengths. Their physical origin remains unclear. Simulations have been able to form galaxies with the requisite luminosities, but have otherwise been unable to simultaneously match the stellar masses, star formation rates, gas fractions and environments. Here we report a cosmological hydrodynamic galaxy formation simulation that is able to form a submillimetre galaxy that simultaneously satisfies the broad range of observed physical constraints. We find that groups of galaxies residing in massive dark matter haloes have increasing rates of star formation that peak at collective rates of about 500-1,000 solar masses per year at redshifts of two to three, by which time the interstellar medium is sufficiently enriched with metals that the region may be observed as a submillimetre-selected system. The intense star formation rates are fuelled in part by the infall of a reservoir gas supply enabled by stellar feedback at earlier times, not through major mergers. With a lifetime of nearly a billion years, our simulations show that the submillimetre-bright phase of high-redshift galaxies is prolonged and associated with significant mass buildup in early-Universe proto-clusters, and that many submillimetre-bright galaxies are composed of numerous unresolved components (for which there is some observational evidence).

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“…These line flux ratios discriminate between AGN photoionization and shock models (e.g., Clark et al 1997;Moy & Rocca-Volmerange 2002), and we have illustrated these models in Figure 7. The photoionization models are computed with CLOUDY (Ferland 1996) and the shock models are computed with MAPPINGSIII (Dopita & Sutherland 1996).…”

Section: Apo/dis Optical Longslit Observationsmentioning

confidence: 99%

An Active Galactic Nucleus Caught in the Act of Turning Off and On

Comerford

Barrows

Müller–Sánchez

et al. 2017

ApJ

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We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z=0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events that could have been triggered by a past interaction with the companion galaxy that is currently located 12.5kpc away. We originally targeted SDSS J1354+1327 because its Sloan Digital Sky Survey spectrum has narrow AGN emission lines that exhibit a velocity offset of 69kms −1 relative to systemic. To determine the nature of the galaxy and its velocity-offset emission lines, we observed SDSS J1354+1327 with Chandra/ACIS, Hubble Space Telescope/ Wide Field Camera 3, Apache Point Observatory optical longslit spectroscopy, and Keck/OSIRIS integral-field spectroscopy. We find a ∼10kpc cone of photoionized gas south of the galaxy center and a ∼1kpc semi-spherical front of shocked gas, which is responsible for the velocity offset in the emission lines, north of the galaxy center. We interpret these two outflows as the result of two separate AGN accretion events: the first AGN outburst created the southern outflow, and then <10 years 5 later, the second AGN outburst launched the northern shock front. SDSS J1354+1327 is the galaxy with the strongest evidence for an AGN that has turned off and then on again, and it fits into the broader context of AGN flickering that includes observations of AGN light echoes.

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High Redshift Quasars, Emission Lines and ‘Cloudy’

Cited by 6 publications

References 24 publications

Observational signatures of massive black hole formation in the early Universe

Observational signatures of massive black hole formation in the early Universe

The formation of submillimetre-bright galaxies from gas infall over a billion years

An Active Galactic Nucleus Caught in the Act of Turning Off and On

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