English
Related papers

Related papers: Neutral Hydrogen Clouds in the M81/M82 Group

200 papers

Nearby interstellar clouds with high (|v| >/= 10 km/s) random velocities although easily detected in NaI and CaII lines have hitherto not been detected (in emission or absorption) in the HI 21cm line. We describe here deep Giant Metrewave…

Astrophysics · Physics 2009-11-06 Rekhesh Mohan , K. S. Dwarakanath , G. Srinivasan , Jayaram N. Chengalur

We have combined observations of Galactic high-velocity HI from two surveys: a very sensitive survey from the Green Bank 140ft Telescope with limited sky coverage, and the less sensitive but complete Galactic All Sky Survey from the 64m…

Astrophysics of Galaxies · Physics 2017-01-18 Vanessa A. Moss , Felix J. Lockman , Naomi M. McClure-Griffiths

The Square Kilometre Array mid-frequency array will enable high-redshift detections of neutral hydrogen (HI) emission in galaxies, providing important constraints on the evolution of cold gas in galaxies over cosmic time. Strong…

Astrophysics of Galaxies · Physics 2024-09-12 Roger P. Deane , Tariq Blecher , Danail Obreschkow , Ian Heywood

We have conducted an HI 21 cm emission-line survey using the Parkes 20cm multibeam instrument and the Australia Telescope Compact Array (ATCA) of six loose groups of galaxies chosen to be analogs to the Local Group. The goal of this survey…

Astrophysics · Physics 2011-02-11 D. J. Pisano , D. G. Barnes , B. K. Gibson , L. Staveley-Smith , K. Freeman , V. A. Kilborn

We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusually large velocity dispersions of more than 100 km/s (FWHM)…

Astrophysics · Physics 2015-06-24 Harald Riffert , Pawan Kumar , W. K. Huchtmeier

I present the results of a search for intergalactic hydrogen clouds in voids. Clouds are detected by their HI LyA absorption lines in the HST spectra of low-redshift AGN. The parameter with which the environments of clouds are characterized…

Astrophysics · Physics 2009-11-07 C. V. Manning

We present the first results of a wide-field mapping survey of the M81 group conducted with Hyper Suprime-Cam on the Subaru Telescope. Our deep photometry reaches $\sim2$ magnitudes below the tip of the red giant branch (RGB) and reveals…

We use spectroscopic data from HST and FUSE to study the wide range of ionization states of the "highly ionized high-velocity clouds". Studied extensively in OVI absorption, these clouds are usually assumed to be infalling gas in the…

Astrophysics · Physics 2009-11-10 J. A. Collins , J. M. Shull , M. L. Giroux

The origin of our Galaxy's high-velocity clouds (HVCs) remains a mystery after many decades of effort. In this paper, we use the TNG50 simulation of the IllustrisTNG project to identify cool, dense clouds that match observations of Galactic…

Astrophysics of Galaxies · Physics 2024-10-21 Scott Lucchini , Jiwon Jesse Han , Lars Hernquist , Charlie Conroy

Optical emission lines provide an important new window on the HVCs. Recent studies of the H-alpha line reveal that ionized gas is pervasively associated with the neutral hydrogen in HVCs. The Wisconsin H-Alpha Mapper (WHAM) instrument has…

Astrophysics · Physics 2007-05-23 S. L. Tufte , R. J. Reynolds , L. M. Haffner

We have analyzed high velocity resolution HI synthesis observations of the nearly face-on Sc galaxy NGC 1232. The neutral gas distribution extends well beyond the optical extent of the galaxy. As expected, local peaks in the HI column…

Astrophysics · Physics 2009-10-31 L. van Zee , J. Bryant

We have used the WSRT to carry out an unbiased wide-field survey of HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2. In this paper we present our HI detections at…

Astrophysics · Physics 2009-11-10 Robert Braun , David Thilker

We present HST GHRS and STIS observations of five QSOs that probe the prominent high-velocity cloud (HVC) Complex C, covering 10% of the northern sky. Based upon a single sightline measurement (Mrk 290), a metallicity [S/H]=-1.05+/-0.12 has…

Compact high-velocity clouds (CHVCs) are the most distant of the HVCs in the Local Group model and would have HI volume densities of order 0.0003/cm^3. Clouds with these volume densities and the observed neutral hydrogen column densities…

Astrophysics · Physics 2009-11-07 Philip R. Maloney , Mary E. Putman

This paper is the first in a series presenting a sample of 29 late-type dwarf galaxies, observed with the Westerbork Synthesis Radio Telescope (WSRT) in the 21-cm line of neutral atomic hydrogen (HI). The sample itself, the HI content of…

Astrophysics · Physics 2009-11-07 J. M. Stil , F. P. Israel

We measure the neutral atomic hydrogen (HI) gas content of field galaxies at intermediate redshifts of z ~ 0.1 and z ~ 0.2 using hydrogen 21-cm emission lines observed with the Westerbork Synthesis Radio Telescope (WSRT). In order to make…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jonghwan Rhee , Martin A. Zwaan , Frank H. Briggs , Jayaram N. Chengalur , Philip Lah , Tom Oosterloo , Thijs van der Hulst

We present a catalogue of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern-sky neutral hydrogen, which has 57 mK sensitivity and 1 km/s velocity resolution and was obtained with the Parkes Telescope. Our…

We report on neutral hydrogen (HI) observations of the NGC 7232 group with the Australian Square Kilometre Array Pathfinder (ASKAP). These observations were conducted as part of the Wide-field ASKAP L-Band Legacy All-sky Blind surveY…

Here I briefly highlight our studies of the gas content, kinematics and star formation in nearby dwarf galaxies (D < 10 Mpc) based on the `Local Volume HI Survey' (LVHIS, Koribalski et al. 2018), which was conducted with the Australia…

Astrophysics of Galaxies · Physics 2020-02-19 B. S. Koribalski

We extend our published work on the neutral hydrogen content of early-type galaxies in the Virgo cluster using the catalogue of detected sources from the ALFALFA survey, by showing the 21cm spectra of all the detected galaxies and…

Astrophysics · Physics 2009-06-23 S. di Serego Alighieri , M. Grossi , C. Giovanardi , S. Pellegrini , G. Trinchieri