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The GALFACTS project is using the L-band seven feed array receiver system on the Arecibo telescope to carry out an imaging spectro-polarimetric survey of the 30% of the sky visible from Arecibo. GALFACTS observations will create full-Stokes…

Instrumentation and Methods for Astrophysics · Physics 2010-08-31 Russ Taylor , Chris Salter

We have used the Nancay Radio Telescope to obtain new global HI data for 16 giant low surface brightness (LSB) galaxies. Our targets have optical luminosities and disk scale lengths at the high end for spiral galaxies (L_B~10^10 Lsun and…

Astrophysics · Physics 2009-10-31 L. D. Matthews , W. van Driel , D. Monnier-Ragaigne

The Spitzer Space Telescope (formerly SIRTF) extragalactic First-Look Survey covered about 5 square degrees centered on J2000 17:18 +59:30 in order to characterize the infrared sky with high sensitivity. We used the 100-m Green Bank…

Astrophysics · Physics 2009-11-10 Felix J. Lockman , J. J. Condon

Green Bank Telescope (GBT) 21cm observations have revealed a faint, yet extensive HI cloud population surrounding the Andromeda Galaxy (M31). The newfound objects are likely analogs to the high-velocity HI clouds (HVCs) seen around the…

CO--0.40--0.22 is a peculiar molecular cloud that is compact and has an extraordinary broad velocity width. It is found in the central molecular zone of our Galaxy. In this direction, there is another cloud with an H$_2$O maser spot at a…

Astrophysics of Galaxies · Physics 2017-05-10 Yuhei Iwata , Haruka Kato , Daisuke Sakai , Tomoharu Oka

Aims: A large scale survey of the Galactic center region in he 3 mm rotational transitions of SiO, HCO+ and H13CO+ (beamsize ~ 3. 6 arcmin) was conducted to provide an estimate of cloud conditions, heating mechanisms, chemistry and other…

Astrophysics of Galaxies · Physics 2015-05-19 D. Riquelme , L. Bronfman , R. Mauersberger , J. May , T. L. Wilson

By comparing sensitive Spitzer Space Telescope (SST) infrared and Green Bank Telescope 21 cm observations, we are able to report the first detection of dust emission in Complex C, the largest High Velocity Cloud in the sky. Dust in the…

Astrophysics · Physics 2009-11-11 M. -A. Miville-Deschenes , F. Boulanger , W. T. Reach , A. Noreiga-Crespo

We present Arecibo 21 cm spectroscopy, Keck HIRES Hb spectroscopy, and WIYN R-band images of 11 nearby blue compact galaxies selected to be similar to blue compact star-forming galaxies at intermediate redshifts (0.1<z<1). We detect HI in…

Astrophysics · Physics 2009-11-06 D. J. Pisano , Henry A. Kobulnicky , Rafael Guzman , Jesus Gallego , Matthew A. Bershady , ;

We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of $N$(HI)$\sim10^{14}$ cm$^{-2}$ using measurements of HI Lyman-series absorption from the Far Ultraviolet Spectroscopic Explorer (FUSE).…

Understanding how the Galactic magnetic field threads the multi-phase interstellar medium (ISM) remains a considerable challenge, as different magnetic field tracers probe dissimilar phases and field components. We search for evidence of a…

In recent years, ultrafaint dwarf (UFD) galaxies have been found through systematic searches of large optical surveys. However, the existence of Leo T, a nearby gas-rich dwarf, suggests that there could be other nearby UFDs that are…

Astrophysics of Galaxies · Physics 2019-07-02 Daniel DeFelippis , Mary Putman , Erik Tollerud

Using data from the ALFALFA Arecibo HI survey of galaxies and the Virgo cluster X-ray pressure profiles from XMM-Newton, we investigate the possibility that starless dark HI clumps, also known as "dark galaxies", are supported by external…

Astrophysics of Galaxies · Physics 2016-06-15 Blakesley Burkhart , Abraham Loeb

We present the catalog of ~31500 extragalactic HI line sources detected by the completed ALFALFA survey out to z < 0.06 including both high signal-to-noise ratio (> 6.5) detections and ones of lower quality which coincide in both position…

We present the results of our search for faint Local Group dwarf galaxies in compact high-velocity clouds (HVCs). We used digitized Palomar Observatory Sky Survey (POSS) data to examine 1 square degree of sky around each of ~250 northern…

Astrophysics · Physics 2009-11-07 Joshua D. Simon , Leo Blitz

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

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 D. J. Pisano , D. G. Barnes , L. Staveley-Smith , B. K. Gibson , V. A. Kilborn , K. C. Freeman

New 21 cm HI observations have revealed a giant HI cloud in the Galactic plane that has unusual properties. It is quite well defined, about 150 pc in diameter at a distance of 5 kpc, and contains as much as 100,000 Solar Masses of atomic…

Astrophysics · Physics 2009-11-06 Anthony H. Minter , Felix J. Lockman , Glen I. Langston , Jennifer A. Lockman

We present deep HI 21-cm and optical observations of the face-on spiral galaxy M 83 obtained as part of a project to search for high-velocity clouds (HVCs) in nearby galaxies. Anomalous-velocity neutral gas is detected toward M 83, with…

Astrophysics · Physics 2011-02-11 Eric D. Miller , Joel N. Bregman , Bart P. Wakker

High-velocity clouds (HVCs) are clouds of HI seen around the Milky Way with velocities inconsistent with Galactic rotation, have unknown distances and masses and controversial origins. One possibility is that HVCs are associated with the…

Sensitive ground-based submillimeter surveys, such as ATLASGAL, provide a global view on the distribution of cold dense gas in the Galactic plane. Here we use the 353 GHz maps from the Planck/HFI instrument to complement the ground-based…

Solar and Stellar Astrophysics · Physics 2016-01-13 T. Csengeri , A. Weiss , F. Wyrowski , K. M. Menten , J. S. Urquhart , S. Leurini , F. Schuller , H. Beuther , S. Bontemps , L. Bronfman , Th. Henning , N. Schneider

High-velocity clouds (HVCs) are interstellar gas clouds whose velocities are incompatible with Galactic rotation. Since the first discovery of HVCs in 1963, their origins have been debated for decades but are still not settled down, because…

Astrophysics of Galaxies · Physics 2025-06-19 Yu-Ting Wang , Chao Liu , Zhi-Yu Zhang