Related papers: Ram Pressure and Anomalous Shell Formation in HoII
Neutral hydrogen VLA D-array observations of the dwarf irregular galaxy HoII, a prototype galaxy for studies of shell formation and self-propagating star formation, are presented. The large-scale HI morphology is reminiscent of ram pressure…
Neutral hydrogen VLA D-array observations of the dwarf irregular galaxy HoII, a prototype galaxy for studies of shell formation, are presented. HI is detected to radii over 16' or 4 R_25, and M_HI=6.44x10^8 M_sun. The total HI map has a…
Results are presented from a wide area, high resolution HI synthesis survey of the outer regions of the nearby M81 group, where internal (galactic) and external (group-related) evolution processes can be studied simultaneously in great…
Numerical hydrodynamical modelling of supernova-driven shell formation is performed with a purpose to reproduce a giant HI ring (diameter 1.7 kpc) in the dwarf irregular galaxy Holmberg I (Ho I). We find that the contrast in HI surface…
The pressures of giant HII regions in 6 dwarf Irregular galaxies are a factor of ~10 larger than the average pressures of the corresponding galaxy disks, obtained from the stellar and gaseous column densities. Either the visible HII regions…
Using a hybrid method which combines non-radiative hydrodynamical simulations with a semi-analytic model of galaxy formation, we determine the ram pressure as a function of halocentric distance experienced by galaxies in haloes with virial…
Dwarf irregular galaxies are unique laboratories for studying the interaction between stars and the interstellar medium in low mass environments. We present the highest spatial resolution observations to date of the neutral hydrogen content…
We present radio and optical observations of Holmberg I (HoI), a member of the M81 group of galaxies (distance 3.6Mpc). HoI is a low-mass, low surface- brightness dwarf galaxy. High-resolution multi-array VLA HI observations reveal a…
Data from the Canadian Galactic Plane Survey reveal an abundance of HI shells and arcs in the disk of our galaxy. While their shape is suggestive of stellar winds or supernovae influence, very few of these structures have been examined in…
High resolution HI observations of nearby dwarf galaxies (most of which are situated in the M 81 group at a distance of about 3.2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are…
We present a deep, wide-field optical study of the M81 group dwarf galaxy Holmberg II (HoII) based on Subaru/Suprime-Cam imaging. Individual stars are resolved down to I~25.2, i.e. about 1.5 mag below the tip of the red giant branch (RGB).…
We present the results of a multiwavelength study of the nearby dwarf galaxy DDO 53 - a relatively isolated member of the M 81 group. We analyse the atomic and ionised gas kinematics (based on the observations with Fabry-Perot…
WLM is an archetypal dwarf irregular galaxy that has not experienced interactions with major Local Group galaxies within the past 8 Gyr. It has recently been shown that WLM is losing its gas due to ram pressure forces exerted by the…
We suggest that large HI holes observed in the interstellar medium (ISM) of galaxies such as the Large Magellanic Cloud (LMC) and Holmberg II (Ho II, DDO 50, UGC 4305) can form as the combined result of turbulence coupled to thermal and…
We present UBVJHKHalpha and HI data of the irregular galaxy NGC 2366. It is a normal boxy-shaped disk seen at high inclination angle. We do not see any unambiguous observational signature of a bar. There is an asymmetrical extension of…
We compare the stellar structure of the isolated, Local Group dwarf galaxy Pegasus (DDO216) with low resolution HI maps from Young et al. (2003). Our comparison reveals that Pegasus displays the characteristic morphology of ram pressure…
We present sensitive and high resolution 21 cm observations of the dwarf irregular (dIm) galaxy DDO 43, in conjunction with optical broad and narrow band images in U, B, V, and Halpha. The observations are used to examine the relationship…
We address the question of whether violent star formation in HII galaxies is induced by low mass companions by describing statistically their local environment as estimated by the correlation function. We argue that even if low mass…
We examine the triggering process of molecular cloud formation around diffuse HII regions. We calculate the time evolution of the shell as well as of the HII region in a two-phase neutral medium, solving the UV and FUV radiative transfer,…
We present 3D hydrodynamic simulations of ram pressure stripping in dwarf galaxies. Analogous studies on this subject usually deal with much higher ram pressures, typical of galaxy clusters, or mild ram pressure due to the gas halo of the…