... These Frontier Fields will combine the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies. ... We are soliciting gravitational lensing maps for the last four Hubble Frontier Fields clusters (MACSJ0717.5+3745, MACSJ1149.5+2223, AbellS1063, and Abell 370) based upon the exceptionally deep HST FF imaging and other new ancillary data. ... For the full set of proposal instructions and requirements, see the FY16 Frontier Fields Lensing Map Call for Proposals....

... Our Sun is part of a huge wheel-shaped collection of stars. ... Astronomers have long suspected it was a very massive black hole, and that every galaxy had such a central mass, created early in the history of the universe. ... However, unless that object happens to be headed directly at the black hole (a relatively small target) it will just swing around and fly away again, like a comet making a pass at the Sun. The velocity acquired in falling towards the black hole also helps it escape. ...

... Credit Copyright: Data - Hubble Legacy Archive , ESA , NASA ; Processing - Al Kelly Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies . ... Publications with keywords: Perseus cluster - active galaxy - magnetic field - X-ray - radio - multiwavelength . Publications with words: Perseus cluster - active galaxy - magnetic field - X-ray - radio - multiwavelength . ... Nearby Spiral Galaxy NGC 4945 . ...

. The tar command can be used to turn several files into a single tarfile . tar can also be used to bundle up whole directories before transferring them to another system. Use tar whenever you want to transfer a number of files or directories between different UNIX systems. Creating an archive file . Making a tarfile smaller . Examine the contents of a tarfile . Unpacking a tar file .

... Editor's choices for the most educational Astronomy Pictures of the Day about spiral galaxies: . APOD: 2003 March 10 - M101: The Pinwheel Galaxy . Explanation: Why do many galaxies appear as spirals ? ... One result is that M101 , also called the Pinwheel Galaxy , has several extremely bright star-forming regions (called HII regions ) spread across its spiral arms. ... APOD: 2003 April 13 - NGC 1365: A Nearby Barred Spiral Galaxy . ... NGC 1365 is a member of the Fornax Cluster of Galaxies . ...

... 1994: . Deep CCD images of the bright gamma-ray bursts GRB790418 and GRB790613 localization regions were obtained for the first time. In both cases, a faint blue star-like object (V = 24.5 m , BV m ) was detected within the region of localization of gamma-ray bursts. ... Based on sixty daily instantaneous spectra of the object SS433, obtained on the RATAN-600 in April-May 1994, we traced its variability in four very powerful flares at five frequencies. ... Archive . ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. June 21, 1999 . The Galactic Center in Infrared . ... Explanation: The center of our Galaxy is a busy place. In visible light , much of the Galactic Center is obscured by opaque dust . In infrared light , however, dust glows more and obscures less, allowing nearly one million stars to be recorded in the above photograph . ...

... Hughes STX/COSSC NASA/GSFC, Greenbelt, MD 20771 . ... The exploration of hypertextual data presentation at the COSSC was facilitated by the creation of tables of data, in electronic form, which describe the BATSE and EGRET datasets available in the Compton Observatory archive. ... As our store of data continues to grow, we will continue to explore new and novel ways in which hypertext allows the data in the COSSC archive to be presented and selected. 56 kB PostScript reprint . ...