We present infrared luminosities, star formation rates (SFR), colors, morphologies, locations, and AGN properties of 24μm -detected sources in photometrically detected high-redshift clusters in order to understand the impact of environment on star formation and AGN evolution in cluster galaxies. We use three newly-identified z = 1 clusters selected from the IRAC dark field; the deepest ever mid...

We present a comprehensive multi-wavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band Hα photometry in the cluster region we have identified candidate young stellar objects (YSOs) distributed in a pattern from the cluster to one of the nearby nebulae Sim 129. Th...

In a poem entitled “A Letter from Caroline Herschel (17501848),” the poet and novefist Siv Cedering attributes the following to the sister of astronomer William Herschel: I have a way with numbers, so I handle the/necessary reductions and calculations. /1 also plan every night’s observation schedule, for he says my/ intuition helps me turn the telescopeto discover/star cluster after star cluste...

Star clusters are found in ∼40% of the Local Group galaxies. Their properties are reviewed. The impact of galaxy environment on the evolution and survival of star clusters is discussed. Possible evidence for cluster formation triggered by galaxy interactions, gradients in cluster size, metallicity and stellar content with galactocentric radius and variations as a function of galaxy type are bri...

We discuss the structural change and degree of mass segregation of young dense star clusters within about 100 pc of the Galactic center. In our calculations, which are performed with GRAPE-6, the equations of motion of all stars and binaries are calculated accurately but the external potential of the Galaxy is solved (semi)analytically. The simulations are preformed to model the Arches star clu...

A limited-area survey of the η Chamaeleontis cluster has identified 2 new late-type members. The more significant of these is ECHA J0843.3–7905 (= IRAS F08450– 7854), a slowly-rotating (P = 12 d) M2 classical T Tauri (CTT) star with a spectrum dominated by Balmer emission. At a distance of 97 pc and cluster age of ≈ 9 Myr, the star is a nearby rare example of an ‘old’ CTT star and promises to b...

We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16− 33% of which are in bright star clusters. We identify 268 star cluster candidates in both the F555W and ...

Context. Despite many studies of the star formation in spiral galaxies, a complete and coherent understanding of the physical processes that regulate the birth of stars has not yet been achieved, nor a unanimous consent was reached, despite the many attempts, on the effects of the environment on the star formation in galaxies member of rich clusters. Aims. We focus on the local and global Schmi...

The currently available empirical evidence on the star formation processes in the extreme, high-pressure environments induced by galaxy encounters, mostly based on high-resolution Hubble Space Telescope imaging observations, strongly suggests that star cluster formation is an important and perhaps even the dominant mode of star formation in the starburst events associated with galaxy interactio...

1 M51 – a star cluster laboratory The young (< 1 Gyr) star cluster population of M51 (NGC 5194, Hubble-type Sc) is, due to its relative proximity and high number of star clusters, an excellent candidate for studies to the formation and evolution of young star clusters (YCs) in spiral disks. M51 has many star clusters because of its high star formation rate, which may have been caused by its int...