Related papers: Star Formation Efficiency in Low Surface Brightnes…
Low-surface-brightness galaxies (LSBGs) -- defined as systems that are fainter than the surface-brightness limits of past wide-area surveys -- form the overwhelming majority of galaxies in the dwarf regime (M* < 10^9 MSun). Using…
The HI in galaxies often extends past their conventionally defined optical extent. I report results from our team which has been probing low intensity star formation in outer disks using imaging in H-alpha and ultraviolet. Using a sample of…
Observations of quiescent dwarfs and low surface brightness galaxies suggest that continuous low rate star formation is likely to occur, during the quiescent phases between bursts, in dwarf galaxies. We thus have used a spectrophotometric…
We studied the morphology of star formation in dwarf irregular galaxies and found that, in general, this takes place on one side of a galaxy and far from the center. This is mainly true for low surface brightness galaxies; in high surface…
I review the evolutionary status of the field populations of starbursting dwarf galaxies and low surface brightness spirals. Particular attention is paid to the long standing problem of the progenitors for star burst galaxies, which may be…
We study the relationship between the gas column density (Sigma_HI) and the star formation rate surface density (Sigma_SFR) for a sample of extremely small (M_B ~ -13, Delta V_50 ~ 30 km/s) dwarf irregular galaxies. We find a clear…
We have used the Spitzer Space Telescope to study the dust properties of a sample of star-forming dwarf galaxies. The differences in the mid-infrared spectral energy distributions for these galaxies which, in general, are low metallicity…
The gas mass fraction (fg) of spiral galaxies is strongly correlated with the central surface brightness of their disks. There exist many dim galaxies with long gas consumption time scales and fg > 0.5. This resolves the gas consumption…
High spatial and spectral resolution observations of the atomic interstellar medium in nearby dwarf galaxies reveal evidence for warm and cold neutral gas, just like the phases in our own Galaxy. The cold or quiescent phase (about 20% of…
The optical and HI properties for a sample of low surface brightness (LSB) dwarf galaxies, cataloged from the Second Palomar Sky Survey, is presented. Gas mass fractions for LSB dwarfs reach the highest levels of any know galaxy type…
(Abridged) The Kennicutt--Schmidt law relates the face-on star formation rate (SFR) per unit area with the face-on gaseous column density in nearby galaxies. Applying this relation to damped Lya absorption systems (DLAs) of neutral hydrogen…
We present B, R, and Halpha imaging data of 19 large disk galaxies whose properties are intermediate between classical low surface brightness galaxies and ordinary high surface brightness galaxies. We use data taken from the Lowell 1.8m…
We attempt to determine the dominant processes acting on star-forming disk galaxies as a result of the cluster environment by studying the normalised rates and radial distributions of star formation in galaxies within low-redshift clusters.…
Massive galaxies in the early Universe have been shown to be forming stars at surprisingly high rates. Prominent examples are dust-obscured galaxies which are luminous when observed at sub-millimeter (sub-mm) wavelengths and which may be…
Young galaxies are clumpy, gas-rich, and highly turbulent. Star formation appears to occur by gravitational instabilities in galactic disks. The high dispersion makes the clumps massive and the disks thick. The star formation rate should be…
Studies by Lada (2010) and Heiderman (2010) have suggested that star formation mostly occurs above a threshold in gas surface density Sigma of Sigma_c = 120 Msun pc^{-2} (A_K = 0.8). Heiderman infer a threshold by combining low-mass…
Low-mass galaxies at high redshifts are the building blocks of more massive galaxies at later times and are thus key populations for understanding galaxy formation and evolution. We have made deep narrow-band observations for two…
Recent observations have revealed that red, optically--passive spiral galaxies with little or no optical emission lines, harbour significant amounts of dust-obscured star formation. We propose that these observational results can be…
We present the result of investigations into two theories to explain the star formation rate-density relationship. For regions of high galaxy density, either there are fewer star forming galaxies, or galaxies capable of forming stars are…
We are using the 2dF spectrograph to make a survey of all objects (`stars' and `galaxies') in a 12 sq.deg region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky…