A Physical Model for the Quasar Luminosity Function Evolution between Cosmic Dawn and High Noon

Abstract

Modeling the evolution of the number density distribution of quasars through the Quasar Luminosity Function (QLF) is critical to improve our understanding of the connection between black holes, galaxies and their halos. Here we present a novel semi-empirical model for the evolution of the QLF that is fully defined after the specification of a free parameter, the internal duty cycle, ${\epsilon }_{DC}$ along with minimal other assumptions. All remaining model parameters are fixed upon calibration against the QLF at two redshifts, $z=4$ and $z=5$. Our modeling shows that the evolution at the bright end results from the stochasticity in the median quasar luminosity versus halo mass relation, while the faint end shape is determined by the evolution of the Halo Mass Function (HMF) with redshift. Additionally, our model suggests the overall quasar density is determined by the evolution of the HMF, irrespective of the value of ${\epsilon }_{DC}$. The $z\ge 4$ QLFs from our model are in excellent agreement with current observations for all ${\epsilon }_{DC}$, with model predictions suggesting that observations at $z\gtrsim 7.5$ are needed to discriminate between different ${\epsilon }_{DC}$. We further extend the model at $z\le 4$, successfully describing the QLF between $1\le z\le 4$, albeit with additional assumptions on $\Sigma$ and ${\epsilon }_{DC}$. We use the existing measurements of quasar duty cycle from clustering to constrain ${\epsilon }_{DC}$, finding ${\epsilon }_{DC}\sim 0.01$ or ${\epsilon }_{DC}\gtrsim 0.1$ dependent on observational datasets used for reference. Finally, we present forecasts for future wide-area surveys with promising expectations for the Nancy Grace Roman Telescope to discover $N\gtrsim 10$, bright, $m_{UV}<26.5$ quasars at $z\sim 8$.

13 pages, 4 figures; accepted for publication in ApJ; data products available at https://github.com/renkeven/QuasarEvolutionData

References in corpus (12)

• The Illustris simulation: the evolving population of black holes across cosmic time
• A Luminous Quasar at Redshift 7.642
• The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• Pōniuā'ena: A Luminous $z=7.5$ Quasar Hosting a 1.5 Billion Solar Mass Black Hole
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• How Mergers May Affect The Mass Scaling Relations Between Black Holes, Galaxies, and Other Gravitationally Bound Systems
• On the Lack of Evolution in Galaxy Star Formation Efficiency
• An improved model for the formation times of dark matter haloes
• Near Infrared Photometric properties of 130,000 Quasars: An SDSS-UKIDSS matched catalog
• The Brightest Galaxies at Cosmic Dawn from Scatter in the Galaxy Luminosity versus Halo Mass Relation
• Stochastic Processes as the Origin of the Double-Power Law Shape of the Quasar Luminosity Function

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• The Black Hole Mass Function Across Cosmic Times II. Heavy Seeds and (Super)Massive Black Holes
• Revisiting the Extreme Clustering of $z\approx 4$ Quasars with Large Volume Cosmological Simulations
• Unresolved z~8 point sources and their impact on the bright end of the galaxy luminosity function
• Gravitational lensing modification of the high redshift galaxy luminosity function