... Ultraluminous X-ray sources (ULXs) are located in external galaxies, their X-ray luminosities (10 39 - 10 41 erg/s) are thousand times greater than those of brightest black holes in the Galaxy. ULXs may be supercritical accretion disks around black holes of stellar masses (~10 Solar masses) like that in SS433, or they may be a hypothetical intermediate-mass black holes (hundreds - thousands Solar masses) with standard accretion disks. ... 2) The ULX progenitors were ejected from the star clusters. ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

... NGC 3603: X-Rays From A Starburst Cluster . ... Explanation: A mere 20,000 light-years from the Sun lies the NGC 3603 star cluster, a resident of the nearby Carina spiral arm of our Milky Way galaxy . Seen here in this recent false-color x-ray image from the Chandra Observatory, NGC 3603 is well known to astronomers as a young cluster in a large galactic star-forming region. ... Publications with keywords: star cluster - NGC 3603 - star formation . ... Starburst Cluster in NGC 3603 . ...

We present ultraviolet, optical, near-infrared, Spitzer mid-infrared, and radio images of 14 radio-selected objects in M33. ... We have detected the majority of cluster candidates in M33 at all wavelengths. ... These results suggest that 11 of the 14 radio-selected objects are optically visible young star clusters with a surrounding H II region, that 2 are background objects, possibly active galactic nuclei (AGNs), and that 1 is a Wolf-Rayet star with a surrounding H II region. ...

Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

... We found that 10 metal-poor globular clusters are greately distinguished for anomalously small masses on the "destruction rate-mass" plain. As it turned out, these poor clusters, situated 15 kpc farther from the Galactic centre, are somewhat younger than the bulk of the metal-poor globulars, and have anomalously red horizontal branches. ... At the same time, deficiency of distant massive clusters is noticeable with increasing distance from the galactic centre. ...

... Now we present the topographical map for the COOC criterion calculated for both galactic X-ray sources taken from Table  4 and binary pulsar species from Table  6 in coordinates the initial mass ratio exponent - mean kick velocity (Figure  26 ). ... Figure 26: The COOC criterion for X-ray galactic sources and binary radiopulsars versus the initial mass ratio exponent and mean space kick velocity for different kick velocity distributions. ...

... Science . ... The goal is to bring together two communitities: the one working on star formation (mostly galactic) and the one working on the formation of young massive clusters (mostly extra-galactic). We will link galactic with extra-galactic work, optical/NIR techniques with sub-mm/mm/radio ones, the formation of stars with the one of massive star clusters - observations and theory. ... Coordinated by Marina Rejkuba (abstract) . ... How did star formation proceed in Globular Clusters? ...

... Australia Telescope Compact Array . ... Compact Stellar Systems in the Fornax Cluster: Super-massive Star Clusters or Extremely Compact Dwarf Galaxies? ... We suggest that these objects are either super-massive star clusters (intra-cluster globular clusters or tidally stripped nuclei of dwarf galaxies) or a new type of low-luminosity compact elliptical dwarf (``M32-type'') galaxy. ... Keywords: galaxies: star clusters -- galaxies: dwarf -- galaxies: formation . ... Properties of the compact objects ...

... 2002 June 17 . NGC 4697: X-Rays from an Elliptical Galaxy . ... Like other normal elliptical galaxies , NGC 4697 is a spherical ensemble of mainly older, fainter, low mass stars, with little star forming gas and dust compared to spiral galaxies. ... An exceptionally large number of NGC 4697's x-ray binaries are found in the galaxy's globular star clusters, suggesting that dense star clusters are a good place for neutron stars and black holes to capture a companion. ... About APOD | ...

Searching for Ultra Compact Binaries in Globular Clusters What Are Ultra Compact Binaries? ... An ultra compact binary is a binary that consists two white dwarf To source the FITS files that contained the UV images, the sky coordinates stars and has an orbital period shorter than ~70min (A binary and the details on brightness for each star in each globular cluster we were consists of two stars orbiting around their centre of mass, it enables investigating, we used the XMM online archive. ...

home resources > books . SEARCH ASP SITE: Match ALL words Match ANY word . ... Buy The Black Hole at the Center of our Galaxy at Amazon.com! Reviewed by Terrell Kent Holmes . In 1974 astronomers discovered a bright radio source at the center of the Milky Way Galaxy, in the direction of the constellation Sagittarius. It was an unknown quantity then, but astronomers now know that the object is a supermassive black hole causing a maelstrom of activity at the galactic center. ...

The HI Mass Function: Open Questions Stephen Schneider University of Massachusetts The Evolution of Galaxies through the Neutral Hydrogen Window 1 February 2008 HI Mass Functions = ­1.5 = ­1.2 Is the bright end variable? Is There One HI Mass Function? ... Also face flux-bias problems when hunting close to noise: promote more weak sources than lose stronger sources Arecibo Slice AGES HI Mass Function to Date The slope is relatively flat for the first 142 galaxies detected. ...

... The ROSAT Bright Survey: II. Catalogue of all high-galactic latitude RASS sources with PSPC countrate CR > 0.2 s -1 . ... 1S We present a summary of an identification program of the more than 2000 X-ray sources detected during the ROSAT All-Sky Survey (Voges et al. 1999) at high galactic latitude, |b| > 30degr , with countrate above 0.2 s -1 . This program, termed the ROSAT Bright Survey RBS, is to more than 99.5% complete. ...

... L. Testi (1), P. Palla (2), A. Natta (2) . 1) Division of Physics, Mathematics and Astronomy, Caltech, MS 105-24, Pasadena, CA 91125, USA . ... We present large field infrared images of a sample of 45 Herbig Ae/Be stars. Stellar parameters, such as age and mass, have been derived for all of them in a consistent way. The images have been used to identify stellar groups or clusters associated with the Herbig Ae/Be star. ... Mantained by: Leonardo Testi . ...

... Astrophysics Group . ... AMI Science . ... Observations of galaxy clusters are central to the AMI science programme. The AMI Small Array is used to observe already-known clusters with high-sensitivity and resolution, allowing us to extract detailed information about individual clusters and to build up statistics about the cluster population. ... Observing galaxy clusters at 15 GHz is tricky because of the contamination from foreground radio sources, which is where the Large Array comes in! ...

... Meta Index / Home Page / Description / Specifying source region shapes . When radiusstyle =`contour', the task calculates the source region shape as an elliptical locus which approximates the contour of the PSF at a given flux value. ... Clearly, in order to calculate the shape of such a flux contour, it is necessary firstly to normalize the PSF to the source brightness and secondly to determine the flux level (in `brightness' units per pixel) at which to find the contour. ...

... What are the fluxes of the stars? ... Volume sampled is no longer 4/3 pi r cubed due to curved space-time Want to derive population properties brightness, size, etc - as function of distance (therefore, cosmic time) But - biases in sample Biases NUMBER OF STARS VS MASS Eddington Bias: in astronomy, there are always more little faint things than big bright things. ... Suppose there are 10 stars of mass 0.5 and 100 stars of mass 0.4, and you have a 20 percent error on measuring the mass. ...

... Structure of Data . ... Catalog . ... In SAI OCL Catalog, we introduce our work on investigation of the Milky Way system of open star clusters. The main goal of our study is a search for new clusters using huge surveys. 168 new clusters have been already discovered by us using J,H,Ks data from 2MASS point source catalog. ... For 141 new clusters, we found their physical parameters using J,H,Ks data from 2MASS catalog and, for a number of clusters, our UBVRI CCD observational magnitudes. ...

... Spectrum-RG is joint project of Russian Federal Space Agency (Roscosmos) and German Space Agency (DLR) of X-ray astrophysical observatory. Its main aim is to make all-sky survey in the X-ray (0.5-11 keV) band in order to find all massive clusters of galaxies in the Universe, millions of active galactic nuclei, including obscured ones and hundreds of thousands of Galactic X-ray sources. ... eRosita (Germany) X-ray grazing-incident mirror telescope, consisting of 432 mirrors combined in 7 modules. ...