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We have undertaken a survey for HI 21-cm absorption within the host galaxies of z ~ 1.2 - 1.5 radio sources, in the search of the cool neutral gas currently "missing" at z > 1. This deficit is believed to be due to the optical selection of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 S. J. Curran , M. T. Whiting , A. Tanna , E. M. Sadler , M. B. Pracy , R. Athreya

We search for weak O VI absorption in the low-redshift intergalactic medium (IGM) using 82 high signal-to-noise quasar spectra obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. From this dataset, we compile…

Astrophysics of Galaxies · Physics 2025-12-12 Sapna Mishra , Vikram Khaire , Romeo Pallikkara , Anand Narayanan , Andrew J. Fox

We present Giant Metrewave Radio Telescope (GMRT) observations of OH absorption in B3~1504+377 ($z \sim 0.673$) and PKS 1413+135 ($z \sim 0.247$). OH has now been detected in absorption towards four intermediate redshift systems, viz. the…

Astrophysics · Physics 2009-11-07 Nissim Kanekar , Jayaram N Chengalur

We present the results of a survey for intervening HI 21-cm absorbers at intermediate and low redshift (0<z<1.2). For our total sample of 24 systems, we obtained high quality data for 17 systems, the other seven being severely affected by…

Astrophysics of Galaxies · Physics 2015-09-09 M. A. Zwaan , J. Liske , C. Péroux , M. T. Murphy , N. Bouché , S. J. Curran , A. D. Biggs

The FAST All Sky HI survey (FASHI) is broader in frequency band and sky volume, and deeper in detection sensitivity than the Arecibo Legacy Fast ALFA survey (ALFALFA). To efficiently expand the sample of OH megamasers (OHMs), whose…

Astrophysics of Galaxies · Physics 2024-08-14 Chuan-Peng Zhang , Cheng Cheng , Ming Zhu , Jin-Long Xu , Peng Jiang

We present a study of extended galaxy halo gas through HI and OVI absorption over two decades in projected distance at $z\approx0.2$. The study is based on a sample of $95$ galaxies from a highly complete ($ > 80\%$) survey of faint…

Astrophysics of Galaxies · Physics 2015-05-04 Sean D. Johnson , Hsiao-Wen Chen , John S. Mulchaey

The Atacama Pathfinder Experiment (APEX) 12m telescope was used to observe the N=1-0, J=0-1 ground state transitions of OH+ at 909.1588 GHz with the CHAMP+ heterodyne array receiver. Two blended hyperfine structure transitions were detected…

Astrophysics of Galaxies · Physics 2015-05-18 F. Wyrowski , K. M. Menten , R. Guesten , A. Belloche

We report on the detection of a population of weak metal-line absorbers in the halo or nearby intergalactic environment of the Milky Way. Using high-resolution ultraviolet absorption-line spectra of bright QSOs obtained with the Space…

Astrophysics of Galaxies · Physics 2014-11-18 Philipp Richter , Jane C. Charlton , Alessio P. M. Fangano , Nadya Ben Bekhti , Joseph R. Masiero

O VI absorption is observed in a wide range of astrophysical environments, including the Local ISM, the disk and halo of the Milky Way, high-velocity clouds, the Magellanic clouds, starburst galaxies, the intergalactic medium, damped…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Andrew J. Fox

Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper (Savage et al. 2014) these far-UV spectra were used to…

I report detections of four new HI 21-cm absorbers associated with sources at intermediate redshifts, 0.7 < z < 1.0. The sources are part of a sample of 11 radio-loud galaxies, all at 0.7 < z < 1.0, that were searched for associated HI…

Astrophysics of Galaxies · Physics 2018-11-28 J. N. H. S. Aditya

We present the results of a search for associated 21 cm HI absorption at redshift 0.42 < z < 1.00 in radio-loud galaxies from three Galaxy And Mass Assembly (GAMA) survey fields. These observations were carried out as part of a pilot survey…

We present an ultraviolet spectroscopic survey of strong H I absorbers in the intergalactic medium, probing their evolution over the last 6-7 Gyr at redshifts $0.24 \leq z \leq 0.84$. We measure column densities $N_{\rm HI} \,( {\rm…

Astrophysics of Galaxies · Physics 2017-11-15 J. Michael Shull , Charles W. Danforth , Evan M. Tilton , Joshua Moloney , Matthew L. Stevans

Galaxy disks are shown to contain a significant population of atomic clouds of 100pc linear size which are self-opaque in the 21cm transition. These objects have HI column densities as high as 10^23 and contribute to a global opacity…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Robert Braun

OH+ absorption is a powerful tracer of inflowing and outflowing gas in the predominantly atomic diffuse and turbulent halo surrounding galaxies. In this letter, we present observations of OH+(1_1-1_0), CO(9-8) and the underlying dust…

Astrophysics of Galaxies · Physics 2023-06-07 Kirsty M. Butler , Paul P. van der Werf , Alain Omont , Pierre Cox

We have detected the four 18cm OH lines from the $z \sim 0.765$ gravitational lens toward PMN J0134-0931. The 1612 and 1720 MHz lines are in conjugate absorption and emission, providing a laboratory to test the evolution of fundamental…

We have measured the 2D 2-point correlation function, Xi_AG, between low column density Ly-alpha absorbers and galaxies at a redshift z ~ 1. We measured Ly-alpha absorbers between redshifts z=0.68 to 1.51 over a total redshift path length…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-08 Allen M. Shone , Simon L. Morris , Neil H. M. Crighton , Richard Wilman

We present a search for associated HI 21 cm absorption in a sample of 29 radio-loud active galactic nuclei (AGNs) at $0.7 < z < 1$, carried out with the upgraded Giant Metrewave Radio Telescope. We detect HI 21 cm absorption against none of…

Astrophysics of Galaxies · Physics 2022-03-30 Suma Murthy , Raffaella Morganti , Nissim Kanekar , Tom Oosterloo

We used Arecibo Observatory and the Green Bank Telescope to observe OH in twelve early-type galaxies with known reservoirs of dense gas. We present three new detections of OH in absorption in the 1667 MHz line. One objective of our survey…

Astrophysics of Galaxies · Physics 2015-06-23 James McBride , Katherine Alatalo , Kristina Nyland

This study presents results on detecting neutral atomic hydrogen (HI) 21cm absorption in the spectrum of PKS1413+135 at redshift $z=0.24670041$. The observation was conducted by FAST, with a spectral resolution of 10 Hz, using 10 minutes of…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-08 Jiangang Kang , Chang-Zhi Lu , TongJie Zhang , Ming Zhu