Related papers: Star-Formation Knots in IRAS Galaxies
Star-forming galaxies are huge reservoirs of cosmic rays (CRs) and these CRs convert a significant fraction of their energy into $\gamma$-rays by colliding with the interstellar medium (ISM). Several nearby star-forming galaxies have been…
The existence of massive ($10^{11}$ solar masses) elliptical galaxies by redshift z~4 (when the Universe was 1.5 billion years old) necessitates the presence of galaxies with star-formation rates exceeding 100 solar masses per year at z>6…
To address the problem concerning the early formation of stars in massive galaxies, we present the results of a semi-analytic model of galaxy formation which includes a physical description of starbursts triggered by galaxy interactions.…
Bars are an elongated structure that extends from the centre of galaxies, and about one-third of disk galaxies are known to possess bars. These bars are thought to form either through a physical process inherent in galaxies, or through an…
Tidal interactions between galaxies can trigger star formation, which contributes to the global star formation rate density of the universe and could be a factor in the transformation of blue, star-forming galaxies to red, quiescent…
Many of the properties of massive stars in external galaxies, such as chemical compositions, mass functions, and ionizing fluxes, can be derived from the study of the associated clouds of ionized gas. Moreover, the signatures of Wolf-Rayet…
We present the results of deep imaging and spectroscopic observations of very extended ionized gas (EIG) around four member galaxies of the Coma cluster of galaxies: RB199, IC4040, GMP2923 and GMP3071. The EIGs were serendipitously found in…
Interacting galaxies surrounded by HI tidal debris are ideal sites for the study of young clusters and tidal galaxy formation. The process that triggers star formation in the low-density environments outside galaxies is still an open…
Cosmological simulations predict the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these filaments has limited tests of this prediction. We…
Star formation in galaxies is triggered by a combination of processes, including gravitational instabilities, spiral wave shocks, stellar compression, and turbulence compression. Some of these persist in the far outer regions where the…
Submillimetre (sub-mm) galaxies have very high infrared (IR) luminosities and are thousands of times more numerous at z~2 than local ultra-luminous IR galaxies. They therefore represent a key phase in galaxy evolution which can be missed in…
I present recent observations and analyses of star cluster formation in a wide variety of environments -- from young star clusters and super star clusters in normal actively star-forming spirals and irregulars to starbursting dwarfs and…
Recent observations with the Hubble Space Telescope have discovered in the nearest planetary nebula, the Helix Nebula, thousands of gigantic comet-like objects with planet like masses in a ring around the central brilliant star at a…
We investigated six H II regions with infrared, bright rimmed bubble or cometary morphology, in search of quantitative evidence for triggered star formation, both collect and collapse and radiatively driven implosion. We identified and…
The dynamics of the inner disk of many galaxies is dominated by bars. As a result, resonances between the bar and the disk become an important factor. In order to detect resonances, we measure angular and radial frequencies of individual…
Old starburst galaxies are deficient in O stars, and hence do not exhibit strong line emission in the optical regime. However, there remain many B stars, which are expected to heat dust grains and generate strong continuum emission in the…
Tiny, dense clumps of sub-solar mass called globulettes form in giant galactic HII regions. The young central clusters compress the surrounding molecular shells which break up into clumps, filaments, and elephant trunks that interact with…
(ABRIDGED) Star-forming small galaxies made out of collisional debris have been found in a variety of merging systems. So far only a few of them are known in ULIRGs although they show clear signs of interactions. Whether external star…
Collisions and mergers of gas-rich galaxies trigger bursts of star and cluster formation. Of the thousands of clusters typically formed during a major merger, only the most massive and compact survive for Gigayears as globular clusters…
The cosmic infrared background (CIRB) is a record of a large fraction of the emission of light by stars and galaxies over time. The bulk of this emission has been resolved by the Infrared Space Observatory camera. The dominant contributors…