Related papers: The Outer Disks of Dwarf Irregular Galaxies
We have compared far-ultraviolet (FUV), near-ultraviolet (NUV), and Halpha measurements for star forming regions in 21 galaxies, in order to characterise the properties of their discs at radii beyond the main optical radius (R25). In our…
When stars form in small groups (N = 100 - 500 members), their circumstellar disks are exposed to little EUV radiation but a great deal of FUV radiation from massive stars in the group. This paper calculates mass loss rates for…
(Abridged) We combine data from The HI Nearby Galaxy Survey and the GALEX Nearby Galaxy Survey to study the relationship between atomic hydrogen (HI) and far-ultraviolet (FUV) emission outside the optical radius (r25) in 17 spiral and 5…
We present the results of an analysis of Pan-STARRS1 Medium Deep Survey multi-band (g,r,i,z,y) images of a sample of 698 low-redshift disk galaxies that span broad ranges in stellar mass, star-formation rate, and bulge/disk ratio. We use…
We investigate the dynamics of starbursting dwarf galaxies, using both new and archival HI observations. We consider 18 nearby galaxies that have been resolved into single stars by HST observations, providing their star formation history…
We examine the star formation properties of galaxies with very thin disks selected from the Revised Flat Galaxy Catalog (RFGC). The sample contains 333 ultra-flat galaxies (UFG) at high Galactic latitudes, $|b|>10^{\circ}$, with a blue…
We present the H$\alpha$ images of ultra-flat (UF) spiral galaxies seen practically edge-on. The galaxies have the angular diameter in the $B$ band $a> 1.9^{\prime}$ and the apparent axial ratio $(a/b) >10$. We found that their H$\alpha$…
Ultra-Diffuse Galaxies are both extreme products of galaxy evolution and extreme environments in which to test our understanding of star formation. In this work, we contrast the spatially resolved star formation activity of a sample of 22…
We study the relationship between the gas column density (derived from GMRT 21 cm data) and the star formation rate surface density (derived from publicly available GALEX data) for a sample of 23 extremely faint dwarf irregular galaxies…
An unresolved question in galaxy evolution is whether the star formation histories of low mass systems are preferentially dominated by starbursts or modes that are more quiescent and continuous. Here, we quantify the prevalence of global…
Crucial to a quantitative understanding of galaxy evolution are the properties of the inter-stellar medium that regulate galactic-scale star formation activity. We present here the results of a suite of star formation models applied to the…
Unsharp-mask images of HI emission from 36 dwarf irregular (dIrr) galaxies illustrate star formation in dispersed clouds and on the rims of large cavities. The cavities can extend for a radial scalelength and typically have circular or…
We present the results of the spectroscopic and photometric follow-up of two field galaxies that were selected as possible stellar counterparts of local high velocity clouds. Our analysis shows that the two systems are distant (D>20 Mpc)…
New deep optical and near-infrared imaging is combined with archival ultraviolet and infrared data for fifteen nearby galaxies mapped in the Spitzer Extended Disk Galaxy Exploration Science survey. These images are particularly deep and…
We determine the intrinsic axial ratio distribution of the 'gas' disks of extremely faint M_B > -14.5 dwarf irregular galaxies. We start with the measured (beam corrected) distribution of apparent axial ratios in the HI 21cm images of dwarf…
We present results from a GALEX ultraviolet (UV) survey of a complete sample of 390 galaxies within ~11 Mpc of the Milky Way. The UV data are a key component of the composite Local Volume Legacy (LVL), an ultraviolet-to-infrared imaging…
Holes and clumps in the interstellar gas of dwarf irregular galaxies are gravitational scattering centers that heat field stars and change their radial and vertical distributions. Because the gas structures are extended and each stellar…
Though smooth, extended spheroidal stellar outskirts have long been observed around nearby dwarf galaxies, it is unclear whether dwarfs generically host an extended stellar halo. We use imaging from the Hyper Suprime-Cam Subaru Strategic…
Based on the LAMOST survey and Sloan Digital Sky Survey (SDSS), we use low-resolution spectra of 130,043 F/G-type dwarf stars to study the kinematics and metallicity properties of the Galactic disk. Our study shows that the stars with…
About 20 percent of all nearby early-type galaxies ($M_{\star} \gtrsim 6 \times 10^{9}$ M$_{\odot}$) outside the Virgo cluster are surrounded by a disc or ring of low-column-density neutral hydrogen (HI) gas with typical radii of tens of…