Giant Metrewave Radio Telescope detection of associated H I 21-cm absorption at z = 1.2230 towards TXS 1954+513

We have used the 610 MHz receivers of the Giant Metrewave Radio Telescope (GMRT) to detect associated HI 21cm absorption from the $z = 1.2230$ blazar TXS1954+513. The GMRT HI 21cm absorption is likely to arise against either the milli-arcsecond-scale core or the one-sided milli-arcsecond-scale radio jet, and is blueshifted by $\approx 328$ km s$^{-1}$ from the blazar redshift. This is consistent with a scenario in which the HI cloud giving rise to the absorption is being driven outward by the radio jet. The integrated HI 21cm optical depth is $(0.716 \pm 0.037)$ km s$^{-1}$, implying a high HI column density, $N_{\rm HI} = (1.305 \pm 0.067) \times ({\rm T_s/100\: K}) \times 10^{20}$ cm$^{-2}$, for an assumed HI spin temperature of 100 K. We use Nickel Telescope photometry of TXS1954+513 to infer a high rest-frame 1216 \AA\ luminosity of $(4.1 \pm 1.2) \times 10^{23}$ W Hz$^{-1}$. The $z = 1.2230$ absorber towards TXS1954+513 is only the fifth case of a detection of associated HI 21cm absorption at $z > 1$, and is also the first case of such a detection towards an active galactic nucleus (AGN) with a rest-frame ultraviolet luminosity $\gg 10^{23}$ W Hz$^{-1}$, demonstrating that neutral hydrogen can survive in AGN environments in the presence of high ultraviolet luminosities.

[1]  India.,et al.  A Giant Metrewave Radio Telescope search for associated H i 21 cm absorption in high-redshift flat-spectrum sources , 2015, 1511.04767.

[2]  R. Morganti,et al.  The HI absorption "Zoo" , 2014, 1411.0361.

[3]  Z. Paragi,et al.  Radio Jets Clearing the Way Through a Galaxy: Watching Feedback in Action , 2013, Science.

[4]  E. Sadler,et al.  A survey for the missing hydrogen in high-redshift radio sources , 2012, 1210.1886.

[5]  M. Whiting,et al.  COMPLETE IONIZATION OF THE NEUTRAL GAS: WHY THERE ARE SO FEW DETECTIONS OF 21 cm HYDROGEN IN HIGH-REDSHIFT RADIO GALAXIES AND QUASARS , 2012, 1204.2881.

[6]  Alexander Y. Wagner,et al.  RELATIVISTIC JET FEEDBACK IN EVOLVING GALAXIES , 2010, 1012.1092.

[7]  M. Murphy,et al.  New searches for H i 21 cm in damped Lyman α absorption systems , 2009, 0910.3742.

[8]  R. Morganti,et al.  Is cold gas fuelling the radio galaxy NGC 315 , 2009, 0908.3951.

[9]  Arlo U. Landolt,et al.  UBVRI PHOTOMETRIC STANDARD STARS AROUND THE CELESTIAL EQUATOR: UPDATES AND ADDITIONS , 2009, 0904.0638.

[10]  P. Giommi,et al.  Roma-BZCAT: A multifrequency catalogue of Blazars , 2008, 0810.2206.

[11]  Paolo Giommi,et al.  CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates , 2007, 0709.1735.

[12]  R. M. Campbell,et al.  A multi-epoch VLBI survey of the kinematics of CJF sources. I. Model-fit parameters and maps , 2007, 0802.4182.

[13]  G. Xie,et al.  The Connections between Accretion, Jets, and Blazar Unification , 2007 .

[14]  S. Longmore,et al.  A survey for redshifted molecular and atomic absorption lines I , 2006, 0805.1581.

[15]  D. J. Saikia,et al.  Probing radio source environments via H i and OH absorption , 2006, astro-ph/0605423.

[16]  Astronomy,et al.  Fast neutral outflows in powerful radio galaxies : a major source of feedback in massive galaxies , 2005, astro-ph/0510263.

[17]  R. Morganti,et al.  The location of the broad H i absorption in 3C 305: clear evidence for a jet-accelerated neutral outflow , 2005, astro-ph/0505365.

[18]  J. Conway,et al.  Observations of H I absorbing gas in compact radio sources at cosmological redshifts , 2003, astro-ph/0304291.

[19]  Leggett,et al.  The USNO-B Catalog , 2002, astro-ph/0210694.

[20]  A. Taylor.  Imaging HI absorption toward symmetric radio galaxies—evidence for a circumnuclear torus , 1999, astro-ph/9911302.

[21]  C. B. Moore,et al.  Neutral Hydrogen 21 cm Absorption at Redshift 2.6365toward the Gravitational Lens MG J0414+0534 , 1998 .

[22]  C. Lawrence,et al.  Optical Spectra of a Complete Sample of Radio Sources. I. The Spectra , 1996 .

[23]  D. R. Henstock,et al.  A Complete Flux-Density--limited VLBI Survey of 293 Flat-Spectrum Radio Sources , 1996 .

[24]  A. Tielens,et al.  X-Ray--irradiated Molecular Gas. I. Physical Processes and General Results , 1996 .

[25]  E. Greisen,et al.  The NRAO VLA Sky Survey , 1996 .

[26]  A. Readhead,et al.  The First Caltech-Jodrell Bank VLBI Survey. III. VLBI and MERLIN Observations at 5 GHz and VLA Observations at 1.4 GHz , 1995 .

[27]  A. Readhead,et al.  The First Caltech-Jodrell Bank VLBI Survey. I. λ = 18 Centimeter Observations of 87 Sources , 1995 .

[28]  J. Conway,et al.  Helical jets and the misalignment distribution for core-dominated radio sources , 1993 .

[29]  G. Nicolson,et al.  The Milliarcsecond Structure of Highly Variable Radio Sources , 1992 .

[30]  Uson,et al.  Radio detections of neutral hydrogen at redshift Z=3.4. , 1991, Physical review letters.

[31]  G. Knapp,et al.  H I Absorption in Radio Elliptical Galaxies---Evidence for Infall , 1989 .

[32]  A. Readhead,et al.  The milliarcsecond structure of a complete sample of radio sources. II: First-epoch maps at 5 GHz , 1988 .

[33]  D. Heeschen.  Flickering of extragalactic radio sources , 1984 .

[34]  Panos K. Chrysanthis,et al.  Signatures , 2018, Encyclopedia of Social Network Analysis and Mining. 2nd Ed..

[35]  Accepted for Publication in Astrophysical Journal (letters) , 2001 .

[36]  Peter D. Barthel,et al.  Is every quasar beamed , 1989 .

[37]  M. S. Roberts.  THE DETECTION OF 21-CENTIMETER HYDROGEN ABSORPTION ARISING FROM WITHIN THE RADIO GALAXY CENTAURUS A. , 1970 .

[38]  M. A. Strauss,et al.  to appear in the Astrophysical Journal Letters Detection of 1.6 × 10 10 M ⊙ of molecular gas in the host galaxy of the z = 5.77 SDSS quasar J0927+2001. , 2022 .