Related papers: An enigmatic HI cloud
M82 is one of the best studied starburst galaxies in the local universe, and is consequently a benchmark for studying star formation feedback at both low and high redshift. We present new VLA HI observations that reveal the cold gas…
Observed HI accretion around nearby galaxies can only account for a fraction of the gas supply needed to sustain the currently observed star formation rates. It is possible that additional accretion happens in the form of low column density…
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…
VIRGOHI21 is an HI source detected in the Virgo Cluster survey of Davies et al. (2004) which has a neutral hydrogen mass of 10^8 M_solar and a velocity width of Delta V_20 = 220 km/s. From the Tully-Fisher relation, a galaxy with this…
HD179821 is an enigmatic evolved star that possesses characteristics of both a post-asymptotic giant branch star and a yellow hyper-giant, and there has been no evidence that unambiguously defines its nature. These two hypotheses are…
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…
Aperture synthesis observations of two HI cloud complexes located in the periphery of the Virgo galaxy cluster are presented. These low HI-mass clouds ($M_{HI}<$ 10$^{9}$) are seen projected on the M region of the western Virgo cluster,…
Radio spectroscopy at 323 MHz using the Arecibo Telescope and the VLA has produced a tentative detection of the 21cm line of neutral hydrogen at Z_abs=3.38716+-0.00007 in absorption against the radio continuum of the QSO MG0201+113 (Z_em =…
Aims: we studied the global distribution and kinematics of the extra-planar neutral gas in the Milky Way. Methods: we built 3D models for a series of Galactic HI layers, projected them for an inside view, and compared them with the…
We present a study of the distribution and kinematics of the neutral gas in the low-inclination Scd galaxy NGC 6946. The galaxy has been observed for 192 hours at 21-cm with the Westerbork Synthesis Radio Telescope. These are among the…
We present high resolution (R ~ 4 km/s) absorption measurements of the interstellar NaI and CaII lines measured towards 14 early-type stars of distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar cluster. The line…
We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…
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…
We present a new high-sensitivity HI observation toward nearby spiral galaxy M101 and its adjacent 2$^{\circ}\times$ 2$^{\circ}$ region using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From the observation, we detect…
We report on VLA HI spectral line observations of five early-type galaxies classified as optically peculiar due to the presence of jets, ripples or other optical "fine structure". We detect HI within the primary beam (30' HPBW) in four of…
We study the properties of low-column density gas clumps in the halo of the Milky Way based on high-resolution 21-cm observations. Using interferometric data from the WSRT and the VLA we study HI emission at low-, intermediate- and high…
With IRAM-30m/HERA, we have detected CO(2-1) gas complexes within 30 arcsec (~100 pc) from the center of M31 amounting to a minimum total mass of 4.2 x 10^4 Msol (one third of the positions are detected). Averaging the whole HERA field, we…
We have undertaken high-resolution follow-up of a sample of high velocity HI clouds apparently associated with M31. Our sample was chosen from the population of high-velocity clouds (HVCs) detected out to 50 kpc projected radius of the…
We investigate the possibility of detecting HI emission from gravitationally lensed HI clouds (akin to damped Lyman-$\alpha$ clouds) at high redshift by carrying out deep radio observations in the fields of known cluster lenses. Such…
HD110432 has gained considerable attention because it is a hard, variable X-ray source similar to gamma Cas. From time-serial echelle data obtained over two weeks during 2005 January and February, we find several remarkable characteristics…