... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2015 April 28 . Massive Nearby Spiral Galaxy NGC 2841 . ... A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major . ... X-ray images suggest that resulting winds and stellar explosions create plumes of hot gas extending into a halo around NGC 2841 . ... About APOD | ...

... 28.04.2015 . ... Credit Copyright: Roberto Colombari Explanation: It is one of the more massive galaxies known. A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major . ... April . ... April 2015 . ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: spiral galaxy . Publications with words: spiral galaxy . ... NGC 3310: A Starburst Spiral Galaxy . ... In the Center of Spiral Galaxy NGC 3521 . ...

... Benaglia, P., Vink, J.S., Marti, J., Maiz Apellaniz, J., Koribalski, B.S. , Crowther, P.A. 2007, A 467, 1265 . Testing the predicted mass-loss bi-stability jump at radio wavelengths . ... Radio Behavior of Four Southern Non-Thermal O-Type Stars . ... Radio evidence on the mass loss bi-stability jump . ... Radio observations of HD93129A: The earliest O star with the highest mass loss? ... Mass loss rate determination of southern OB stars . ... Mass loss rate determinations of southern Of stars . ...

Image -- Jim Flood, Max Mutchler (Space Telescope Science Institute), and NASA. The Hubble image shows clusters of hot, young, blue stars in a 3,000 light-year segment of NGC 1808's starburst region. The ground-based image shows a faint halo surrounding the galaxy's disk - the aftereffect of dust filaments being ejected from the core by massive stars that exploded as supernovae in the starburst region. ... 1 April 1998 . for the July 1998 edition of Astronomy magazine) ...

... Kopylov, A.I., Kopylova, F.G. "Structure of galaxy groups and clusters and measurement of their masses", . ... Kopylova, F.G., Kopylov, A.I. "Peculiar motions of galaxy clusters and groups in the Hercules and Leo supercluster regions", . ... Kopylova, F.G., Kopylov, A.I. "Analysis of the properties of clusters of galaxies in the region of the Leo supercluster", . ... Kopylova, F.G., Kopylov, A.I. "Analysis of the properties of clusters of galaxies in the region of the Ursa Major supercluster", . ...

... Ultra-compact dwarf galaxies (UCDs): . ... UCDs are characterised by old stellar populations, are larger, brighter and more massive than the biggest Milky Way globular clusters (GCs), but at the same time significantly more compact than typical dwarf galaxies of comparable luminosity. ... UCDs are remnant nuclei of tidally stripped dwarf galaxies ( Bassino et al. ... UCDs are genuine compact dwarf galaxies formed in the smallest peaks of primordial dark matter fluctuations ( Drinkwater et al. ...

home publications > mercury . ... Big Clusters, Tiny Galaxies . ... Astronomers struggle to understand why giant star clusters form in the tiniest of galaxies . ... These clusters are probably young versions of globular clusters, but they are commonly called super star clusters. Seven dwarf galaxies within 16 million light-years have formed super star clusters, with one of these galaxies, NGC 1569, possessing two young clusters. ... Super star clusters have a lot to tell us about star formation. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Stars . ... Starbursts are short-lived events, stars are forming so quickly that the reservoirs of interstellar gas from which stars are coalescing would be used up on a timescale much shorter than the age of the galaxy . ... Strong stellar winds from giant new stars in the starburst region combine with the blasts of supernovae to push a mighty flood of extremely hot gas, a ?superwind? from the galaxy thousands of light years into intergalactic space. ...

In order to measure the density of the Universe, it is necessary to sample a region that is larger than the scale on which the Universe becomes approximately homogeneous. ... When applied to clusters of galaxies we find a mass to luminosity ratio that implies a density of the Universe that is about 0.3 times the critical density. ... Thus the mass-to-muinosity ratio appears to vary with the size of the region measured, from 3 in the solar neighborhood to 30 in galaxies to 300 in clusters of galaxies. ...

GALAXIES cenA .tiff 40 Bright Radio Galaxy M31.tiff Nikon Andromeda Galaxy (note HII regions in spiral arms) ngc6744.tiff 40 NGC 6744 a face-on spiral clouds_20d.tiff H'blad The Magellanic Clouds our nearest neighbours Lmc_7.tiff Nikon The Large Magellanic Clouds Lmc_zoom.tiff Nikon Detail of previous image smc_7.tiff Nikon The Small Magellanic Clouds smc-zoom.tiff Nikon Detail of previous image 30dor_40_BVR.tiff 40 The 30 Dor ... B [OIII] Halpha trifid.tiff 40" The Trifid Nebula. ...

... STScI-PRC00-08 HUBBLE OPENS ITS EYE ON THE UNIVERSE AND CAPTURES A COSMIC MAGNIFYING GLASS Scanning the heavens for the first time since the successful December 1999 servicing mission, NASA's Hubble Space Telescope has imaged a giant, cosmic magnifying glass, a massive cluster of galaxies called Abell 2218. ... The cluster is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. ... Blue pinpoints hot young...

Star formation is often best manifested by bright H II regions.These are regions of hydrogen which have been ionized by ultraviolet photons which are emitted from massive stars (typically stars more than 20 times the mass of the Sun). ... A narrowband filter image centered on this wavelength will then readily reveal these H II regions and hence the current sites of star formation in a galaxy, The luminous blobs that can be seen here are all H II regions . ... NGC 3558 Visual . NGC 3558 Infrared . ...

... Session 1 - Stars, star formation, stellar populations and planets . 9.20 10.00 . ... HST Spectroscopy of the Hottest White Dwarfs . ... Coffee break . ... Lunch break . ... A (long) look at neutron stars with HST . ... Session 2 - Nearby galaxies, bulges, spheroids, galaxy formation . ... New HST/ACS Insights into the Evolution of Star-Forming Dwarf Galaxies with Extreme Properties of Cosmological Relevance . ... Deriving properties of Lyman-break galaxies at z~3-5 using HST/VLT/Spitzer data . ...

... The relationship of the mass and the observed galactocentric distance R -- (a), and that of the mass and the total dissipation velocity n taken from Gnedin, Ostriker (1997) -- (b). The dotted line in diagram (a) shows the "cone of survival" according to the paper by Surdin and Arkhipova (1998) . ... The solid line is a regression stright line for the main sequence of clusters, and the dotted line parallel to it separates the sequence of clusters of anomalously small mass shown by open triangles. ...

... Dept. for Physics of Stars&Galaxies . ... Using a database view Sloan Digital Sky Survey (SDSS), containing almost a million spectra created 15,000 sample galaxies with active star formation, which is used for various studies and physical state of evolution of galaxies. ... Star clusters of the Galaxy . The project MWSC (Milky Way Star Clusters) directory using 2MASS, which includes nearly 500 million vision to the limit Ks = 15.3, analyzed more than 4,000 cluster-like objects in the galaxy. ...

A Canadian and American team of Astronomers have used the 305-m wide Arecibo radio dish, the world's largest and most sensitive radio telescope, to uncover a dozen new super-fast-spinning pulsars. The team directed their search for these rare and exotic stars by pointing the Arecibo radio telescope towards massive star clusters, called Globular Clusters, orbiting our Milky Way galaxy. ... One of the most exotic residents in the Globular cluster system are the millisecond pulsars. ...

... Tonight's Sky . ... Observing . ... Sky this Month . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... galaxies . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Mysterious phenomena in a gigantic galaxy-cluster collision . ... Only registered members of Astronomy.com are allowed to comment on this article. ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

... Visible Distribution of Galaxies. ... Features of Elliptical, Lens-Shaped, Spiral and Irregular Galaxies. Galaxies with Bar. ... Distribution of Surface Brightness of Surface and Spiral Galaxies. ... Color Characteristics of Galaxies. ... Methods of Galaxies' Mass Determination. ... Hidden Mass of Spiral Galaxies. ... Features of Dark Matter Distribution in E and SO Galaxies. ... The Whole Number of Galaxies and Their Density by the Results of Observation on the 'Hubble' Space Telescope. ...

Central Bodies Masses of Selected Globular Clusters N.A.Shakht, A.A.Kiselev, Yu.N.Gnedin and E.A.Grosheva. The Main Astronomical (Pulkovo) Observatory RAS 47 Tuc ­NGC 104 RA 00 24 .1 Dec -72° 04 .9 Size = 30.9 mvis + 4. 0 m D from = 12,1 kpc, h m Cen - NGC 5139 NGC 6397 (Ara) RA 17 h40.m7 Dec -53o 40'.4 Size = 31',0 mvis + 5,3m D from =2.3 kpc RA 13h 26m .8 Dec -47° 28 6 Size = 36.3 m vis +3. 7 m D from =15.8 ±1.1 kpc, 12109 years, Age: 10109 years, (13.4 ± 0.8)109 years. ...

Next: Low-Mass Star Formation Up: M.D. Smith Previous: M.D. Smith Contents . Massive stars are of elevated importance in our Universe for several reasons. ... During their lives, they influence the nurseries in which new stars might form. ... He and Michael Smith investigated the consequences of massive star formation in one such region of our Galaxy. They uncovered that massive stars are forming in the Rosette Molecular Complex at a rate way beyond previous expectations. ...