Related papers: Evolutionary Status of Dwarf ``Transition'' Galaxi…
A less explored aspect of dwarf galaxies is their metallicity evolution. Generally, dwarfs have lower metallicities than Hubble sequence late type galaxies but in reality, dwarfs span a wide range of metallicities with several open…
In order to investigate the nature of dwarf Low Surface Brightness (LSB) galaxies we have undertaken a deep B and I band CCD survey of a 14 sq degree strip in the Virgo Cluster and applied a Fourier convolution technique to explore its…
We present new deep, wide-field Large Binocular Telescope (LBT) $g$ and $r$ imaging data from the Smallest Scale of Hierarchy Survey (SSH) revealing previously undetected tidal features and stellar streams in the outskirts of six dwarf…
The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources and set important constraints on the stellar birthrate at high redshifts.…
We present a study of a large, statistically complete sample of star-forming dwarf galaxies using mid-infrared observations from the {\it Spitzer Space Telescope}. The relationships between metallicity, star formation rate (SFR) and…
We present the photometric and spectroscopic results of a survey done in a wide-field area of nearby groups and poor clusters. The main goals are identifying and characterizing the properties of low-surface-brightness dwarf galaxies and…
We present Halpha narrow-band imaging of 17 dwarf irregular galaxies (dIs) in the nearby Centaurus A Group. Although all large galaxies of the group have a current or recent enhanced star formation episode, the dIs have normal star…
We present ultraviolet integrated and azimuthally-averaged surface photometric properties of a sample of 44 dIm, BCD, and Sm galaxies measured from archival NUV and FUV images obtained with GALEX. We compare the UV to Halpha and V-band…
We present Arecibo Legacy Fast ALFA (ALFALFA) and follow-up Giant Metrewave Radio Telescope (GMRT) HI observations of the gas-rich interacting group NGC 3166/9. The sensitive ALFALFA data provide a complete census of HI-bearing systems in…
In order to recognize environmental effects on the evolution of dwarf galaxies in clusters of galaxies, it is first necessary to quantify the properties of objects which have evolved in relative isolation. With oxygen abundance as the gauge…
We present deep Halpha images of three nearby late-type spiral galaxies (NGC628, NGC1058 and NGC6946), which reveal the presence of HII regions out to, and beyond, two optical radii (defined by the 25th B-band isophote). The outermost HII…
We report the first sub-kiloparsec spatial resolution measurements of strongly inverted gas-phase metallicity gradients in two dwarf galaxies at $z$$\sim$2. The galaxies have stellar masses $\sim$$10^9M_\odot$, specific star-formation rate…
We present visible and near-infrared images of the amorphous dwarf galaxy NGC 1705 in the $B$, $V$, $R$, $J$, $H$, and $K$ bands. Optical and near infrared colors in the galaxy are consistent with a composite population with colors similar…
Systematic studies have revealed hundreds of ultra-compact dwarf galaxies (UCDs) in the nearby Universe. With half-light radii $r_h$ of approximately 10-100 parsecs and stellar masses $M_*$ $\approx$ $10^6-10^8$ solar masses, UCDs are among…
Thanks to the capabilities of modern telescopes and instrumentation, it is now possible to resolve single stars in external dwarf galaxies, provided they are bright enough. For galactic regions with deep enough photometry, detailed…
We use a complete, unbiased sample of 257 dwarf (10^8 MSun < Mstar < 10^9.5 MSun) galaxies at z < 0.08, in the COSMOS field, to study the morphological mix of the dwarf population in low-density environments. Visual inspection of extremely…
The images of 229 galaxies in the Canada France Redshift Survey have been classified on the DDO system. These observations were combined with previous classifications of galaxies with known redshifts in the Hubble Deep Field. The combined…
Following the discovery of spiral structure in IC3328 (Jerjen et al.~2000), we present further evidence that a sizable fraction of bright early-type dwarfs in the Virgo cluster are genuine disk galaxies, or are hosting a disk component.…
We study dwarf galaxies in the Centaurus A group to investigate their metallicity and possible environmental effects. The Centaurus A group (at ~4 Mpc from the Milky Way) contains about 50 known dwarf companions of different morphologies…
We present deep H$\alpha$ imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5m telescope. An effective bandpass of $\sim$13\AA\ is used,…