Detecting and Characterizing Young Quasars II: Four Quasars at $z\sim 6$ with Lifetimes $<10^4$ years

Abstract

The extents of proximity zones of high-redshift quasars enable constraints on the timescales of quasar activity, which are fundamental for understanding the growth of the supermassive black holes (SMBHs) that power the quasars' emission. In this study, we obtain precise estimates for the ultraviolet (UV) luminous lifetimes of ten quasars at $5.8<z<6.5$. These objects were pre-selected to have short lifetimes based on preliminary measurements of their proximity zone sizes, and were then targeted for high quality follow-up sub-mm, optical, and infrared observations required to increase the measurements' precision and securely determine their lifetimes. By comparing these proximity zone sizes to mock quasar spectra generated from radiative transfer simulations at a range of different lifetimes, we deduce extremely short lifetimes $t_{\mathrm{Q}}<10^4$ yr for four objects in our sample, whereas the remaining quasars are consistent with longer lifetimes of $t_{\mathrm{Q}}\gtrsim 10^5$ yr. These young objects with small proximity zones represent $\lesssim 10\%$ of the quasar population as a whole. We compare our results in detail to other studies on timescales of quasar activity, which point towards an average lifetime of $t_{\mathrm{Q}}\sim 10^6$ yr for the quasar population. This is consistent with finding newly turned on quasars approximately $\sim 1-10\%$ of the time. These young quasars represent an unique opportunity to study triggering and feedback mechanisms of SMBHs, since the onset of their UV luminous quasar phase happened only recently, and therefore traces of this process might still be observable.

re-submitted to ApJ

References in corpus (27)

• The NumPy array: a structure for efficient numerical computation
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• A luminous quasar at a redshift of z = 7.085
• A Luminous Quasar at Redshift 7.642
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• 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
• Physical properties of 15 quasars at $z\gtrsim 6.5$
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• A Significantly Neutral Intergalactic Medium Around the Luminous z=7 Quasar J0252-0503
• High-redshift AGN in the Chandra Deep Fields: the obscured fraction and space density of the sub-$L_{\ast }$ population
• The nature and evolution of the highly ionized near-zones in the absorption spectra of z~6 quasars
• HST-COS Observations of AGN. II. Extended Survey of Ultraviolet Composite Spectra from 159 Active Galactic Nuclei
• Clustering of quasars in SDSS-IV eBOSS : study of potential systematics and bias determination
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• Extremely metal-poor gas at a redshift of 7
• 400 pc Imaging of a Massive Quasar Host Galaxy at a Redshift of 6.6
• IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function
• Constraints on the correlation between QSO luminosity and host halo mass from high-redshift quasar clustering
• New Constraints on Quasar Evolution: Broad Line Velocity Shifts over $1.5\lesssim z\lesssim 7.5$
• The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 Myr
• Hyperaccreting black holes in galactic nuclei
• Helium reionization and the thermal proximity effect
• Joint NuSTAR and Chandra analysis of the obscured quasar in IC 2497 - Hanny's Voorwerp system
• On the Search for Quasar Light Echoes
• Joint Bayesian Estimation of Quasar Continua and the Lyman-Alpha Forest Flux Probability Distribution Function

Cited by in corpus (26)

• The X-shooter/ALMA Sample of Quasars in the Epoch of Reionization. II. Black Hole Masses, Eddington Ratios, and the Formation of the First Quasars
• Chronicling the reionization history at $6\lesssim z\lesssim 7$ with emergent quasar damping wings
• The Search for the Farthest Quasar: Consequences for Black Hole Growth and Seed Models
• The need for obscured supermassive black hole growth to explain quasar proximity zones in the epoch of reionization
• On the Connection between Supermassive Black Hole and Galaxy Growth in the Reionization Epoch
• The Assembly of Black Hole Mass and Luminosity Functions of High-redshift Quasars via Multiple Accretion Episodes
• New quasar proximity zone size measurements at $z\sim 6$ using the enlarged XQR-30 sample
• X-ray emission from a rapidly accreting narrow-line Seyfert 1 galaxy at z=6.56
• Revisiting the Extreme Clustering of $z\approx 4$ Quasars with Large Volume Cosmological Simulations
• Constraining the Radio Properties of the $z$=6.44 QSO VIK J2318$-$3113
• Proximate molecular quasar absorbers: Chemical enrichment and kinematics of the neutral gas
• Probing quasar lifetimes with proximate $21$-centimetre absorption in the diffuse intergalactic medium at redshifts $z\ge 6$
• Finding of a population of active galactic nuclei showing a significant luminosity decline in the past $\sim 10^{3-4}$ yrs
• Prospects for Observing High-redshift Radio-loud Quasars in the SKA Era: Paving the Way for 21-cm Forest Observations
• Photometric IGM Tomography: Efficiently Mapping Quasar Light Echoes with Deep Narrow Band Imaging
• Unravelling the formation of the first supermassive black holes with the SKA pulsar timing array
• Detecting and Characterizing Young Quasars. III. The Impact of Gravitational Lensing Magnification
• A comparison of numerical methods for computing the reionization of intergalacitc hydrogen and helium by a central radiating source
• A unique window into the Epoch of Reionisation: A double-peaked Lyman-$\alpha$ emitter in the proximity zone of a quasar at $z\sim 6.6$
• Quasar lifetime measurements from extended Ly$\alpha$ nebulae at $z\sim 6$
• Prospects for constraining quasar ages with fiber spectrographs: quasar-induced Ly$\alpha$ emission from the intergalactic medium
• The effect of helium reionization on the Lyman-alpha forest hydrogen flux statistics
• First constraints on the local ionization topology in front of two quasars at z ~ 7.5
• The Contribution of AGN Accretion Disks to Hydrogen Reionization
• Measurements of quasar proximity zones with the Ly$\alpha$ forest of DESI Y1 quasars
• A Super-Eddington, Lensing-Magnified Quasar at $z=5.07$ observed with JWST