... An Unexpected Flare from the Crab Nebula . ... Credit Copyright: NASA , DOE , Fermi LAT , R. Buehler ( SLAC , KIPAC ) Explanation: Why does the Crab Nebula flare? ... As recently as one month ago, gamma-ray observations of the Crab Nebula by the Fermi Gamma Ray Space Telescope showed an unexpected increase in gamma-ray brightness, becoming about five times the nebula's usual gamma-ray brightness, and fading again in only a few days. ... Publications with keywords: Crab Nebula - gamma ray . ...

... 2011 May 23 . An Unexpected Flare from the Crab Nebula . ... As recently as one month ago, gamma-ray observations of the Crab Nebula by the Fermi Gamma Ray Space Telescope showed an unexpected increase in gamma-ray brightness, becoming about five times the nebula's usual gamma-ray brightness, and fading again in only a few days. ... The above image shows how the Crab Nebula normally appears in gamma rays, as compared to the Geminga pulsar, and how it then appeared during the recent brightening. ...

A team of U.S. and German astrophysicists have made the first ever detection of X-rays coming from a comet. ... Following the initial detection, the team reported repeated X-ray emissions from the comet over the next 24 hours. ... One preliminary theory is that X-ray emission from the Sun was absorbed by a cloud of gaseous water molecules surrounding the nucleus of the comet, and then were re-emitted by the molecules in a process physicists call "fluorescence." ... Comets . ...

... Jitter is usually very small in magnitude and random in effect, and is not expected to lead to systematic throughput changes. ... However, such a change should lead to an obvious decline in the strength of the comparison lines at one end of the spectrum relative to the other and not an overall decline in counts. No such effect is seen (the counts decline evenly from one end of the spectrum to the other). ... The value changes steadily, but not by enough to account for the changes in counts seen. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... 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....

... Green ESO . ... Observations made using the HARPS spectrograph at ESOтАЩs La Silla Observatory in Chile have revealed unexpected changes in the bright spots on the dwarf planet Ceres. Although Ceres appears as little more than a point of light from the Earth, very careful study of its light shows not only the changes expected as Ceres rotates, but also that the spots brighten during the day and also show other variations. ... ArtistтАЩs view of bright spots on Ceres imaged by the Dawn spacecraft . ...

. " The Arecibo Observatory is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations . expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

... Actual stars are expected to be more complicated than these simulations. ... The spot may be entirely visible most of the time (one would observe a prolonged flux minimum low), and then part of it may disappear over the horizon briefly and then return (slow rise and then fall back to constant level). ... With the set of observations taken here, I have information available from several comparison stars and color information. ... The period found must be consistent with the data from any given night....

... XMM-Newton SOC Home Page Conferences & Meetings . ... Data Analysis SAS News What is SAS? How to use SAS SAS Workshops SAS Version Changes Download and Install SAS Science Simulator (SciSim) . ... EPIC cameras optical loading . ... The PI is invited to cross-check the expected X-ray flux from the target source (and from any other potentially bright source in the target field of view), or to provide the SOC with her/his own estimate, if not originally specified in the proposal. ...

In autumn 1994, two groups of astronomers announced that they had discovered Cepheid variable stars in a distant cluster of galaxies. ... As the term suggests, variable stars change in brightness over time. ... Variable stars are an ideal way to get high-school students doing real science, with real data, from the real sky. ... a sky chart to find the stars . ... Students can use the nearby stars to estimate the magnitude of Delta. ... Locate the star Delta in Cepheus and estimate its brightness . ...

Supernova 2000cl in NGC 3318 This page is devoted to information on Supernova 2000cl in NGC 3318 Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main page . Information on the original web pages for many of these images can be found on the Supernova links web page. ... Robin Chassagne's Supernova in NGC 3318 web page in French [ Translate ] . ... Robin Chassagne image . ... and Lidman image . ... vsnet-alert 4896 ] SN 2000cl in NGC 3318 . ...

... December 30, 1998 . Supernova 1994D and the Unexpected Universe . Credit: High-Z Supernova Search Team , HST , NASA . Explanation: Far away, long ago, a star exploded. ... Supernova 1994D was not of interest for how different it was, but rather for how similar it was to other supernovae . ... The large number and great distances to supernovae measured in 1998 have been interpreted as indicating that we live in a previously unexpected universe . ... About APOD > . ... NASA Technical Rep.: ...

... Next, the screen displays "Press 0 to align or Mode for Menu." Press "0" if you wish to begin Automatic alignment (or Easy Align, depending on your telescope model), or press Mode if you wish to choose a manual alignment method ("Automatic Alignment" displays, and you can press MODE to go through the menu to find other alignments). ... Note: If you press the "?" key while "Ctr Brightest Star" displays, the alignment star that AutoStar has chosen will display. ... Alignment successful" displays. ...

... We compare our results with the GRANAT X-ray observations of the Galactic center (Churazov et al. ... It is instructive to compare our results for the Galactic center starburst with what might be expected for a continuous star formation, with the average rate characteristic for the whole Galaxy. For this continuous star formation model, we would expect to observe in the region of around the Galactic center about 10% of the total number of X-ray sources in the Galaxy. ...

... The top quark, discovered at the Tevatron in 1995 and not long ago re-discovered at the LHC, is strongly coupled to the Higgs sector and therefore expected to be related to electroweak symmetry breaking. ... I will talk about the basics of jet substructure analysis, our top tagging approach and several applications for top physics, especially stop searches and the potential of the ttbar forward-backward asymmetry measurement at the LHC. 4:00pm, 472 Willamette Hall . ... return to top . ...

... Two new LBV stars have been discovered in the Andromeda Galaxy. ... In Figure 1 the spectral energy distributions for six stars are shown: upper row - the newly discovered LBV stars, middle row - two well-known LBV stars Var A-1 and AE And, the lower row - two new B[e]-supergiant stars in Andromeda. ... Infrared spectra of the stars in the Andromeda Galaxy: two classical LBVs Var A-1 and AE And, two new LBVs J004526.62 and J004051.59, and two new B[e]-supergiants J004417.10 and J004444.52. ...

... НЕПРЕРЫВНОГО МАТЕМАТИЧЕСКОГО ОБРАЗОВАНИЯ . ... Кружок ?Олимпиады и математика? ... Московская математическая олимпиада . Заочный математический конкурс . ... Устные математические олимпиады . Олимпиады по программированию . Математический праздник . Математические регаты . ... Математические бои . Олимпиада по геометрии им. И.Ф.Шарыгина . ... Программа ?Math in Moscow? Научные конкурсы . Творческий конкурс . ... График олимпиад . ... XXVII Математический праздник . ...