... Anemic Galaxy NGC 4921 at the Edge . ... Credit: NASA , ESA , K. Cook ( LLNL ) Explanation: How far away is spiral galaxy NGC 4921? ... Toward this goal, this image was taken by the Hubble Space Telescope in order to help identify key stellar distance markers know as Cepheid variable stars. Since NGC 4921 is a member of the Coma Cluster of Galaxies , refining its distance would also allow a better distance determination to one of the largest nearby clusters in the local universe. ...

... 2004 February 17 . Galaxy Cluster Lenses Farthest Known Galaxy . ... Explanation: Gravity can bend light, allowing whole clusters of galaxies to act as huge telescopes. Almost all of the bright objects in this just- released Hubble Space Telescope image are galaxies in the cluster known as Abell 2218. ... The power of this massive cluster telescope has recently allowed astronomers to detect a galaxy at a redshift of about 7, the most distant galaxy or quasar yet measured. ... About APOD | ...

... We have simulated the observations of a very distant cluster of galaxies at high redshift. ... The simulations are made for the HST instruments FOC, WFPC II, and the Advanced Camera, and for an 8-m telescope on the ground equipped with adaptive optics. ... A comparison of the fields of view of post-COSTAR HST imaging instruments with the Advanced Camera (AC) and the ground-based adaptive optics camera (AO) is shown in Fig. 1 superimposed on the noise-free cluster simulation. ...

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. ...

ESO PR Photo 18b/00 . ... Caption : Images of two of the novae in NGC 1316 that were discovered during the observational programme described in this Press Release. ... In particular, no less than four novae were detected in a single giant galaxy within only 11 days . ... Moreover, the discovery of four novae in one galaxy in the Fornax cluster was possible with only 3 hours of observing time per filter. ... ESO Press Information is available on the WWW at . http://www.eso.org/outreach/press-rel/ . ...

... 2.3 Establishing the Extragalactic Distance Scale . ... 2.3.2 The Second Rung: Distances to stellar clusters . ... 2.3.4 Distances to Local Group Galaxies . ... The Luminosity Function of Planetary Nebulae . ... 3.2.2 Clusters of Galaxies . ... 4.2 Evidence for Dark Matter as a Function of Scale Size . ... 4.3 Other Dark Matter Indicators for Galaxies . ... What is the nature of the large-scale distribution of matter in the universe as traced by the three-dimensional galaxy distribution? ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

... A tussle in the distant Universe. This Hubble Space Telescope image shows evidence for a merger between a quasar and a companion galaxy. The quasar is the bright object just beneath the image center, and the wisps of material around it are remains of a galaxy disrupted by the interaction between it and the quasar. ... Galactic Nuclei: Old Quasars? Quasars as Probes of the Distant Universe . ... Quasars. ... The name quasar is made up with parts of the words "quasi-stellar radio." ...

... About ATMoB . ... The Observing Committee is starting an Observing Awards Program to promote observing among the membership of the Amateur Telescope Makers of Boston. ... Participant must be a current member of the Amateur Telescope Makers of Boston . ... To qualify for your Observing Award Certificate, turn in your worksheet and drawings to an ATMoB Observing Committee member or observing@atmob.org . ... This Excel sheet has useful macros. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

... 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. ...

... Scaling relations of galaxies: . ... 2007) . ... This research is now being extended to other clusters such as Hydra and Centaurus, by Ingo Misgeld . ... 2007 , Misgeld et al. 2008 and 2009 ) support a picture where the scaling relations of dwarf galaxies are shaped more by internal than external agents, given that colour-magnitude and magnitude-surface brightness relations agree quite well between the low-density Local Group environment and dense clusters like Fornax and Hydra. Misgeld et al. ...

... 87.1083Owen+ VIII/29 1400-MHz Survey of 1478 Abell Clusters of Galaxies (Owen+ 1982) ================================================================================ A 1400-MHz Survey of 1478 Abell Clusters of Galaxies Owen F.N., White R.A., Hilldrup K.C., Hanisch R.J. =1982AJ.. ... 0,] Major axis error 70- 71 A2 --- n_MajAxi *[ A, B, C,NR, ] Major axis note 73- 74 I2 arcmin MinAxi *? ... Note on dist-C: Ratio of the distance of the source from the cluster center to the corrected Abell cluster...

... VLA observations and Tully-Fisher distances of gas-poor spiral galaxies in the Virgo Cluster Region . ... The HI-H2 Pressure Relation In Early-Type Galaxies . ... Tracing evolution of early-type spirals through the neutral hydrogen window . ... An Arecibo HI 21-cm Absorption Survey of Rich Abell Clusters . ... The Arecibo Ultra-Deep Survey . ... Absorption in varying galactic environments seen in HI surveys . ... Early-type galaxies with neutral hydrogen in the Virgo cluster from the ALFALFA survey ...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... This paper ( Burke et al. 2003 ) describes the creation of one such catalogue - the Southern Serendipitous High-redshift Archival ROSAT Cluster (SHARC) survey - which covers an area of 17.7 deg 2 and consists of 32 clusters with redshifts between 0.05 and 0.7 and X-ray luminosities between 7 x 10 42 and 4 x 10 44 erg/s: the high-redshift subsample contains 16 clusters with = 0.3 and X-ray luminosities greater than 2 x 10 43 erg/s (luminosities are quoted for the 0.5 - 2.0 keV energy band). ... 1997 ...

Rastorguev А.S. "Astronomical Distances" (Lecture course for postgraduates, 2009-2016) . Part 1. ... Trigonometric parallaxes of stars. Moving clusters distances. ... Photometric distances: general approach. Normal stars as "standard candles". ... Main Sequence fitting or distance scale of star clusters. ... Moving photospheres technique. Cepheid distance scale and P-L relations. RR Lyrae distance scale. ... Globular clusters luminosity function. ...

... Home Gallery Astrophotography Deep Sky Images by Joe DiNapoli . ... Deep Sky Images by Joe DiNapoli . ... Deep Sky Gallery by Ed Fox . ... Beyond New York City . ... Observing Resources for Amateur Astronomers - Part 1: Beginning Observers . Observing Resources for Amateur Astronomers - Part 2: Intermediate Observers . ... A History of the First Forty Years of the Amateur Astronomers Association . ... 2016 Amateur Astronomers Association of New York Designed by Press Customizr Powered by . ...

... a spiral galaxy some million light years away, made by combining images . ... 1st February using the Armagh Robotic Telescope at the Armagh Observatory. ... Image credit: Simon Jeffery. Astronomers Simon Jeffery and Jack Wright have obtained their first images of deep-space objects using a new тАЬroboticтАЭ telescope at Armagh Observatory. ... Simon Jeffery, project scientist for the new telescope, said: "After two years of hard work, it is very satisfying to see the first images looking so good. ...

Elliptical galaxies Elliptical galaxies Rough subdivision · Normal ellipticals. ... Dwarf ellipticals (dE's). ... E dE BCD dSph 1013 - 1014 108 - 1013 107 - 109 109 107 - 108 300-1000 1-200 1-10 3 0.1­0.5 100 10­100 1­10 0.1­10 5­100 Elliptical galaxies Shapes of elliptical galaxies Elliptical galaxies Shapes of elliptical galaxies Elliptical galaxies Shapes of elliptical galaxies Elliptical galaxies Shapes of elliptical galaxies Elliptical galaxies ...

... Courtesy of NASA/ESA Observation data (J2000 epoch) Constellation Right ascension Declination Redshift Distance Type Serpens Caput 15h 17m 14.4s[] +21° 35 08[] 12,740±50 km/s[][1] 600±30 Mly (183±8 Mpc)[1] SA0(r) [citation needed ] [a] Apparent dimensions (V) 0.28 в 0.28[] Apparent magnitude (V) 16.0[] Notable features Ring galaxy Other designations PGC 54559,[] PRC D-51[] See also: Galaxy, List of galaxies Hoag's Object is a non-typical galaxy of the type known as a ring galaxy. ...