ﻻ يوجد ملخص باللغة العربية
VLA and Parkes 64 m radiotelescope 21-cm observations of the starburst dwarf galaxy NGC 5253 reveal a multi-component non-axisymmetric HI distribution. The component associated with the stellar body shows evidence for a small amount of rotational support aligned with the major axis, in agreement with optically measured kinematics and consistent with the small galaxian mass. Approximately 20-30% of the HI emission is associated with a second component, an HI plume extending along the optical minor axis to the southeast. We consider outflow, inflow, and tidal origins for this feature. Outflow appears improbable, inflow is a possibility, and tidal debris is most consistent with the observations. These observations also reveal a filamentary third component that includes an 800 pc diameter HI shell or bubble to the west of the nucleus, coinciding with an Halpha shell. The mass of HI in the shell may be as large as ~4x10^6 Msun. This large mass, coupled with the lack of expansion signatures in the neutral and ionized gas (v<30 km/s), suggests that this feature may be an example of a starburst-blown bubble stalled by interaction with a massive neutral envelope. Many other HI kinematic features closely resemble those seen in Halpha emission from the ionized gas, supporting the interpretation of neutral and ionized gas outflow at velocities of ~30 km/s. Comparison between extinction estimates from the Balmer emission-line decrement and the HI column densities suggest a gas-to-dust ratio 2-3 times the Galactic value in this low-metallicity (Z=1/4 Zsun) galaxy.
There are few observational constraints on how the escape of ionizing photons from starburst galaxies depends on galactic parameters. Here, we report on the first major detection of an ionization cone in NGC 5253, a nearby starburst galaxy. This high
We present high-spatial-resolution ($sim 0farcs2$, or $sim$3,pc) CO(2--1) observations of the nearest young starburst dwarf galaxy, NGC,5253, taken with the Atacama Large Millimeter/submillimeter Array. We have identified 118 molecular clouds with av
We present HI observations performed at the GMRT of the nearby dwarf galaxy NGC 1560. This Sd galaxy is well-known for a distinct wiggle in its rotation curve. Our new observations have twice the resolution of the previously published HI data. We der
We report the detection of CO(2-1) and 3.1 mm and 1.3 mm continuum emission towards the extremely young starburst in NGC 5253, with data taken from the Owens Valley Millimeter Array. Faint CO emission originates in five molecular clouds distributed a
We present new VLA C+D-array HI observations and optical and NIR imaging of the well known interacting system NGC 4038/9, ``The Antennae. The radio data reveal a wealth of gaseous sub-structure both within the main bodies of the galaxies and along th