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Related papers: A Bigger Cloud 9? New HI Observations of the RELHI…

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We report HI 21-cm line observations of the AGB star X Her obtained with the Green Bank Telescope (GBT) and the Very Large Array (VLA). We have detected HI emission totaling M_HI=2.1e-03 M_sun associated with the circumstellar envelope of…

Solar and Stellar Astrophysics · Physics 2015-05-20 L. D. Matthews , Y. Libert , E. Gerard , T. Le Bertre , M. C. Johnson , T. M. Dame

Reionization-Limited $H_{I}$ Clouds (RELHICs) are starless dark matter halos retaining a significant neutral hydrogen($H_{I}$ ) reservoir. The gas resides in near hydrostatic equilibrium within the dark matter potential and in thermal…

Astrophysics of Galaxies · Physics 2026-05-15 Francesco Turini , Alejandro Benitez-Llambay

HI-rich starless halos, should they exist, hold great promise for elucidating properties of dark matter halos. This Letter examines the properties of HI-rich failed halos at redshift zero across state-of-the-art cosmological simulations…

Using the first data release of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All-Sky HI survey (FASHI), we compile a catalogue of 70 dark galaxy candidates (DGCs) within 50 Mpc. We select DGCs without an identified…

We present an analysis of the HI and CO gas in conjunction with the Planck/IRAS submillimeter/far-infrared dust properties toward the most outstanding high latitude clouds MBM 53, 54, 55 and HLCG 92-35 at b = -30 deg to -45 deg. The CO…

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has the largest aperture and a 19-beam L-band receiver, making it powerful for investigating the neutral hydrogen atomic gas (HI) in the universe. We present HiFAST…

We use a new, improved version of the HI Parkes All-Sky Survey to search for HI emission from nine new, ultra-faint Milky Way satellite galaxy candidates recently discovered in data from the Dark Energy Survey. None of the candidates is…

Astrophysics of Galaxies · Physics 2015-08-19 T. Westmeier , L. Staveley-Smith , M. Calabretta , R. Jurek , B. S. Koribalski , M. Meyer , A. Popping , O. I. Wong

We report the discovery of eleven high-velocity HI clouds at Galactic latitudes of 25-30 degrees, likely embedded in the Milky Way's nuclear wind. The clouds are detected with deep Green Bank Telescope 21 cm observations of a $3.2^\circ…

Astrophysics of Galaxies · Physics 2025-07-08 Rongmon Bordoloi , Andrew J. Fox , Felix J. Lockman

We present a second catalog of HI sources detected in the Arecibo Legacy Fast ALFA Survey. We report 488 detections over 135 square degrees, within the region of the sky having 22h<RA<03h and +26deg<Dec<+28deg. We present here the…

The emission from neutral hydrogen (HI) clouds in the post-reionization era (z < 6), too faint to be individually detected, is present as a diffuse background in all low frequency radio observations below 1420 MHz. The angular and frequency…

Astrophysics · Physics 2009-10-29 Somnath Bharadwaj , Shiv K. Sethi , Tarun Deep Saini

HII regions made of gas ionized by radiations from young massive stars, are widely distributed in the Milky Way. They are tracers for star formation, and their distributions are correlated with the Galactic spiral structure. Radio…

Astrophysics of Galaxies · Physics 2021-11-03 Chuan-Peng Zhang , Jin-Long Xu , Guang-Xing Li , Li-Gang Hou , Nai-Ping Yu , Peng Jiang

We observed the classical interacting galaxy M51 with FAST and obtain high sensitivity HI image with column density down to 3.8 $\times$ 10$^{18}$ cm$^{-2}$. In the image we can see a diffuse extended envelope around the system and several…

Astrophysics of Galaxies · Physics 2023-02-15 Haiyang Yu , Ming Zhu , Jin-Long Xu , Mei Ai , Peng Jiang , Yanbin Yang

We present the first results of the Herschel open time key program, Galactic Observations of Terahertz C$^+$ (GOT C+) survey of the [CII] fine-structure line at 1.9 THz (158 microns) using the HIFI instrument on Herschel. We detected 146…

Astrophysics of Galaxies · Physics 2015-05-19 W. D. Langer , T. Velusamy , J. L. Pineda , P. F. Goldsmith , D. Li , H. W. Yorke

We report the detection of a largely ionized very-high velocity cloud (VHVC; $v_{\rm LSR}\sim-350$ km/s) toward M33 with the Hubble Space Telescope/Cosmic Origin Spectrograph. The VHVC is detected in OI, CII, SiII, and SiIII absorption…

Astrophysics of Galaxies · Physics 2017-11-02 Y. Zheng , J. K. Werk , J. E. G. Peek , M. E. Putman

We have observed the NGC 2403 group of galaxies using the Robert C. Byrd Green Bank Telescope (GBT) in a search for faint, extended neutral hydrogen clouds similar to the clouds found around the M81/M82 group, which is located approximately…

Astrophysics of Galaxies · Physics 2015-05-13 Katie M. Chynoweth , Glen I. Langston , Kelly Holley-Bockelmann , Felix J. Lockman

Neutral hydrogen mapping of several small, very low column density High Velocity Clouds (HVC), using the Arecibo telescope, is reported. Some were found serendipitously superimposed at distinct velocities on largerHVCs; others were found to…

Astrophysics · Physics 2009-11-10 G. Lyle Hoffman , E. E. Salpeter , Ajay Hirani

We have recently identified several high velocity (V < -100 km/s) clouds in the directions of Mrk 509 and PKS 2155-304 that have unusual ionization properties. The clouds exhibit strong C IV absorption with little or no detectable low ion…

Astrophysics · Physics 2009-10-30 Kenneth R. Sembach , Blair D. Savage , Limin Lu , Edward M. Murphy

We present a deep HI survey at L-band conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) over the COSMOS field. This survey is strategically designed to overlap with the MIGHTEE COSMOS field, aiming to combine…

The Green Bank Telescope has been used to search for 21cm HI emission over a large area between the galaxies M31 and M33 in an attempt to confirm at 9.1 arcmin angular resolution the detection by Braun and Thilker (2004) of a very extensive…

Astrophysics of Galaxies · Physics 2015-06-05 Felix J. Lockman , Nicole L. Free , Joseph C. Shields