... 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. ...

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. ...

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... Next: Cheating Poisson: A Up: Statistical Analysis Previous: Spatial Models and . ... The spatial distribution of stars in the Local Group dwarf irregular galaxy NGC 6822 has been studied, using recent positions and deep photometry for about 15,000 stars in the galaxy. Based on photometrical data, OB stars and red stars could be studied separately. Spatial statistical tools have been applied to the analysis of the spatial structure. ... Figure: Model selection by the aid of CAIC . ...

FGS Instrument Handbook for Cycle 24 . ... Fine Guidance Sensor Instrument Handbook for Cycle 24 > Appendix B: FGS1r PerformanceSummary > B.2 Angular Resolution Test . ... At the time of the test, the predicted angular separation of the components was 0.085" (Franz and Wasserman, private communication). ... By rolling the HST in 6 increments, the projected separation along the X axis varied from the predicted angular resolution limit of FGS1r (~6 mas) to the resolution limit of FGS3 (~20 mas). ...

... 2014 Science Highlights . The Radio Relics and Halo of El Gordo, a Massive z = 0.870 Cluster Merger . Lindner et al. (2014) present 610 MHz and 2.1 GHz imaging of the massive Sunyaev-Zel'dovich Effect selected z = 0.870 cluster merger ACT-CL J0102-4915 ("El Gordo"), obtained with the Giant Metrewave Radio Telescope (GMRT) and the Australia Telescope Compact Array (ATCA), respectively. ... ATNF Science Highlights from refereed publications during 2014. | ... today * ATNF | ... ATCA | ...

Next: J.E. Chambers, Research Astronomer Up: Research Previous: Research Contents . ... Solar Variability and Climate . Other Activities . ... Applied to data of flares on Gliese866 he was able to estimate the area of hydrogen emitting flare regions as 1-13% of the stellar surface. ... As partners in the project, Armagh Observatory has been asked to contribute to the selection process in exchange for priority access to the data which will eventually flow from the satellite. ...

... Values have been scaled arbitrarily. High ratios are shown in blue, corresponding to blue colors, and low ratios are shown in red, corresponding to red colors. ... Noise combined with background subtraction difficulties in the lower left quadrant of the WISP1 data (see Fig. \ref{Fig:wisp_snr_mskd}) make colors in this area very unreliable. ... The values shown here are typically a factor of ~3 less than those calculated for the Schmidt data, shown in Figure \ref{Fig:bj_alpha}. ...

... The study of the Large-scale structure of the Universe and measurements of the Dark Energy equation of state; The exploration of the growth and cosmological evolution of supermassive Black holes in the Universe. ... In course of the all sky survey SRG will discover about 100 000 galaxy clusters and 3 million AGNs. Galaxy clusters are the largest gravitationally bounded objects in the Universe and are best explored through the study of X-ray emission from the hot intergalactic gas. ... 2016 IKI RAN ...

Chandra Calibration: Plans, Status, Future Herman L. Marshall ( Chandra X-ray Center, MIT Kavli Institute) HRMA Cal Summary · · · · · · · · Ground calibration Reflectivity measurements on witness samples Metrology of optical surfaces Positioning ... for finite source size and distance · Testing each quadrant of each shell separately · Allowing for illumination differences to flight Flight verification Imaging star with both ACIS and HRC Effective ...

... Galactic or open star clusters are relatively young swarms of bright stars born together near the plane of our Milky Way Galaxy. Separated by about a degree on the sky, two nice examples are M46 (upper left) 5,400 light-years in the distance and M47 (lower right) only 1,600 light-years away toward the nautical constellation Puppis . Around 300 million years young M46 contains a few hundred stars in a region about 30 light-years across. ... M7: Open Star Cluster in Scorpius . ...

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... In 1930, Trumpler noticed that linear diameters (LD) of open clusters increase with distance (D) from the Sun. ... Since that time, the interstellar absorption has become one of the best studied factor in astrophysics, and we may hope that current OCL distance scales are free from this LD-D correlation. To verify if this is the case we have chosen several modern OCL distance scales and test them with the same clusters and the same angular diameters that Trumpler had used back in 1930. ...

... 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. ...

THE SUBSYSTEMS OF THE MILKY WAY HALO. ... A catalogue of homogeneous fundamental astrophysical parameters for 145 globular clusters is composed on the base of the data of compilative catalogue by Harris (1997) and from another literature. ... In addition, it has large rotation velocity ( V rot =77?33 km/s), appreciable radial and vertical metallicity gradients equal by value, and has the oldest average age (subsystem of the old halo). ... Characteristic parameter of globular cluster subsystems. ...

My main research interests are: . ... The method showed that the star formation in the external disc was quenched about 200 Myr ago, because of the gas removal due to the ram pressure (Pappalardo et al. ... Molecular gas and dust in spiral discs. ... Dust removal in spiral discs. ... Starting from this consideration I am at present analyzing all the spirals discs in the HeVICS sample, to find evidences of dust removed or strongly perturbed by environments, both ram pressure and/or tidal interactions. ...

... Дни открытых дверей к юбилею САО РАН (12-14 апреля 2016 г.) . Международная конференция "Dark Ages and White Nights (Spectroscopy of the CMB)" (20-24 июня 2016 г.) . ... Международная конференция MULTI-SPIN GALAXIES - 2016 (26-30 сентября 2016 г.) . Международная астрономическая конференция "Физика звезд: от коллапса до коллапса" (3-7 октября 2016 г.) Архив . ... Подробнее.. ... 10.02.16 . ... БТА в реальном времени . ... Цейсс-1000 в реальном времени . ... Последнее обновление: 22/03/2016 ...

... 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! ...

... Archives . ... my first AAS. ... I was questioned by two attendees, acquainted before the AAS, if I can suggest them clustering methods relevant to their projects. ... classification vs. clustering or supervised learning vs. unsupervised learning : the former terms from the pairs indicate the fact that the scientist already knows types of objects in his hands. ... Tags: Classification , clustering , cosmology , spatial statistics , supervised learning , test , unsupervised learning . ...

... BLUE STRAGGLER STARS are unusually hot and bright stars found in the cores of ancient star clusters known as globulars. ... BACKGROUND (from wikipedia): Blue straggler stars are stars in open or globular clusters that are hotter and bluer than other cluster stars having the same luminosity. ... There is evidence in favor of this view, notably that blue straggler stars appear to be much more common in dense regions of clusters, especially in the cores of globular clusters. ...