A search for HI 21cm absorption toward the highest redshift radio loud objects

Abstract

We have searched for HI 21cm absorption toward the two brightest radio AGN at high redshift, J0924--2201 at $z=5.20$, and J0913+5919 at $z=5.11$, using the Giant Meter Wave Radio Telescope (GMRT). These data set a 3$\sigma$ upper limit to absorption of $<30$ at 40 km s${}^{-1}$ resolution for the 30 mJy source J0913+5919, and $<3$ for the 0.55 Jy source J0924--2201 at 20 km s${}^{-1}$ resolution. For J0924--2201, limits to broader lines at the few percent level are set by residual spectral baseline structure. For J0924--2201 the column density limit per 20 km s ${}^{-1}$ channel is: N(HI) $<2.2\times 10^{18}{\mathrm{T}}_{\mathrm{s}}$ cm${}^{-2}$ over a velocity range of -700 km s${}^{-1}$ to $+1180$ km s${}^{-1}$ centered on the galaxy redshift determined through CO emission, assuming a covering factor of one. For J0913+5919 the column density limit per 40 km s${}^{-1}$ channel is: N(HI) $<2.2\times 10^{19}{\mathrm{T}}_{\mathrm{s}}$ cm${}^{-2}$ within $\pm 2400$ km s${}^{-1}$ of the optical redshift. These data rule out any cool, high column density HI clouds within roughly $\pm 1000$ km s${}^{-1}$ of the galaxies, as are often seen in Compact Steep Spectrum radio AGN, or clouds that might correspond to residual gas left over from cosmic reionization.

arXiv commentaccepted to the Astronomical Journal; 7 figures; 9 pages aastex format

References in corpus (22)

• A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Observational constraints on Cosmic Reionization
• Cosmological Reionization by Stellar Sources
• Probing the Ionization State of the Universe at z>6
• A Radio Galaxy at z=5.19
• HI 21cm absorption beyond the epoch of re-ionization
• A deep search for 21cm absorption in high redshift damped Lyman-$\alpha$ systems
• The 21 cm Forest: Radio Absorption Spectra as Probes of Minihalos Before Reionization
• NICMOS observations of high redshift radio galaxies: witnessing the formation of bright elliptical galaxies?
• Discovery of six Ly alpha emitters near a radio galaxy at z ~ 5.2
• High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data VI. Sloan Digital Sky Survey Spectrograph Observations
• Sensitive observations at 1.4 and 250 GHz of z > 5 QSOs
• Undetected Sources Allow Transmission of the Lyman-alpha Line From Galaxies Prior to Reionization
• CO(1-0) & CO(5-4) observations of the most distant known radio galaxy at z=5.2
• 21 cm Absorption Studies with the Square Kilometer Array
• Redshifts and Neutral Hydrogen Observations of Compact Symmetric Objects in the COINS Sample
• The detectability of HI 21-cm absorption in damped Lyman-alpha systems
• A Statistical Analysis of Intergalactic Medium Transmission Approaching Reionization
• Detection of HI 21 cm-line absorption in the Warm Neutral Medium and in the Outer Arm of the Galaxy
• Cosmic Variance In the Transparency of the Intergalactic Medium After Reionization
• HI 21cm probes of reionization, and beyond

Cited by in corpus (23)

• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• Reionization and the Cosmic Dawn with the Square Kilometre Array
• Exploring Reionization-Era Quasars III: Discovery of 16 Quasars at $6.4\lesssim z\lesssim 6.9$ with DESI Legacy Imaging Surveys and UKIRT Hemisphere Survey and Quasar Luminosity Function at $z\sim 6.7$
• A survey for redshifted molecular and atomic absorption lines - II. Associated HI, OH and millimetre lines in the z >~ 3 Parkes quarter-Jansky flat-spectrum sample
• A powerful radio-loud quasar at the end of cosmic reionization
• New Insights on the z-alpha Correlation from Complete Radio Samples
• HI 21-cm absorption and unified schemes of active galactic nuclei
• Associated 21-cm absorption towards the cores of radio galaxies
• Prospects for detecting the 21cm forest from the diffuse intergalactic medium with LOFAR
• CO observations of high-z radio galaxies MRC 2104-242 and MRC 0943-242: spectral-line performance of the Compact Array Broadband Backend
• AzTEC 1.1 mm images of 16 radio galaxies at 0.5<z<5.2 and a quasar at z=6.3
• Redshifted intergalactic 3He+ 8.7 GHz hyperfine absorption
• Ionisation of the atomic gas in redshifted radio sources
• The radio spectral turnover of radio-loud quasars at $z>5$
• Atomic and Molecular Absorption in Redshifted Radio Sources
• Evolution of cold gas at 2<z<5: a blind search for HI and OH absorption lines towards mid-infrared color selected radio-loud AGNs
• Statistical Detection of IGM Structures during Cosmic Reionization using Absorption of the Redshifted 21 cm line by HI against Compact Background Radio Sources
• Observations by GMRT at 323 MHz of radio-loud quasars at $z>5$
• The mid-infrared properties and gas content of active galaxies over large look-back times
• FLASH Pilot Survey: Detections of associated 21 cm HI absorption in GAMA galaxies at 0.42 < z <1.00
• Further Observational Evidence for a Critical Ionising Luminosity in Active Galaxies
• Prospects of a statistical detection of the 21-cm forest and its potential to constrain the thermal state of the neutral IGM during reionization
• HI absorption from the epoch of reionization and primordial magnetic fields