... 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. ...

Seven months ago, on Mar 19, 2008, at 09:12 Moscow time, a new star appeared on the sky. The Sun had already risen over the Russia, but people of the Western hemisphere might be able to see by their eyes a faint starlet near one of Bootes constellation stars. This starlet appeared and faded by an order of magnitude in a minute. Astronomers named it GRB080319B or, informally, the Naked-Eye Burst, as it was twice as bright as human eye can see a star. ... Royal Astronomical Society . ...

... On 11mar08 a sine wave was injected into the pdev baseband mixers to measure the mixer and pdev A/D levels. ... Onset of compression. 7dbm input, 9 dbm output , 15 dbm attenuation. ... A 9 dbm output will generate a sine wave with an amplitude of 2047 A/D counts. -8dbm input, 9 dbm output, 0 dbm attenuation. ... with 15 db attenuation, the mixer input is 7 dbm, H3-5 amp needs to output 22.5 dbm . with 0 db attenuation , the mixer input is -15 dbm, the H3-5 amp needs to output 22.5 dbm. ...

... In this first example, we allow an object to fall onto a small radar unit . The resulting Time-Frequency distribution is shown as a contour plot in Fig. 8 (a). Figure: FIGURE GOES SOMEWHERE IN THIS GENERAL VICINITY . ... Its density plot appears as an image in Fig. ... The response has a very high peak, as evidenced from Fig. ...

... Blazar spectral energy distributions (SEDs) are double peaked and follow a self-similar sequence in luminosity. The so-called "blue" blazars, whose first SED component peaks at X-ray energies, are TeV sources, although with a relatively small fraction of their bolometric luminosities. The "red" blazars, with SED peaks in the infrared-optical range, appear to emit relatively more power in the gamma-ray component but at much lower energies (GeV and below). ... toolan@stsci.edu . ...

... I DENTIFY Identify data points . W INDOW Change display area . R ANGE Enter new range of display . E DIT Edit data . ... E RRORS Display error ellipses . F LAGGED Display flagged data too . ... Use the period of that orbit where the selected component appears alone. Subtract the systemic velocity of that binary component. O RBIT Superpose apparent orbit . Christian Hummel 2015-04-28 ...

... PPTA timeline . ... List of projects . ... However, our time series are not equally sampled, so classical spectrum analysis cannot be applied immediately. ... Normally when analysing time series with very steep spectra one would use a "prewhitening" technique and perhaps a low sidelobe spectral window (e.g. the Hanning window). ... The idea is to separate the steep and flatter spectrum components so they can be analysed separately. ... The upper panel has raw data, interpolated data and red...

Classroom Activity: Making a Rainbow . ... When white light from the Sun or a light bulb passes through a prism, the light splits into its component wavelengths. ... Red, blue, green colored filters - if possible, cut 1x4-inch pieces of the filters for each student . ... Many students have the misconception that filters somehow dye the light a certain color. ... Younger students can draw the rainbow and make up a mnemonic for remembering the order of the colors (such as, ROY G. BIV). ...

... A rare type of galaxy known as a Polar Ring, NGC 4650A is composed of an old central group of stars and a young ring of stars rotating farther out. ... Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's head or a sombrero hat. ... Moon Occults Saturn . ... On September 18, 1997, many stargazers in the U. S. were able to watch a lovely early morning lunar occultation as a bright Moon passed in front of Saturn. ...

This Directory contains mean hour values of geomagnetic field components at observatories in Russia and other repub- lic of Former Soviet Union (FSU). The List of these observatories has indication of Data Years. ... Files are prepared in the DOS format. The Format for mean values follows after this list of the geomagnetic observatories. ... 21-116 24I4 24 4-digit hourly mean values for the day. ... If any of the hourly mean values for the day are missing 9999 will appear as the daily mean. ...

... Schubert calculus and Gelfand­Zetlin polytopes (with Valentina Kiritchenko and Vladlen Timorin), 32 pages, preprint, 2011. Available on arXiv:1101.0278. ... Springer fiber components in the two columns case for types A and D are normal (with Nicolas Perrin), Bulletin de la Sociґ ґ Mathґ ete ematique de France, to appear, 2011. ... Bruhat order for two subspaces and a flag, 30 pages, preprint, 2007. Available on arXiv:math/0704.3061. ... English translation: Moscow Univ. Math. ...

... These are the systems which contain compact components of different nature, white dwarf, neutron star or black hole. ... Pulsar appears during X-ray outbursts, but it does not manifest itself in the quiet state (Be stars, BQ Cam, V490 Cep); -falling of low -mass bodies on a compact object due to gravitational capture (a comet nucleus or a meteoroid ) in the detached system (V934 Her, V4641 Sgr). ... B1V-B2Ve star + neutron star & pulsar on the 20.85-day orbit Cep X-4 (ROSAT/PSPC) 1993 . ... 1000/ . ...

... OOF software . ... Memos . ... Raw data . ... We present a Bayesian approach to calculating the coefficients that convert the outputs of ALMA 183 GHz water-vapour radiometers into estimates of path fluctuations that can be used to correct the observed interferometric visibilities. ... Please note that the files"COPYING" in each of the distribution packages have GPL listed but it is in fact LGPL which applies. ... This is the raw data from the SMA used in the analysis shown in Section 4 of the memo. ...

... December 1, 1997 . Orion: The Big Picture . ... Explanation: Orion is big. Some of the stars that form the constellation of Orion are part of a giant gas cloud complex that stretches over 100 light years and appears more than 50 times the diameter of the Moon. Components of this cloud include the Horsehead Nebula , the Orion Nebula , the Trapezium open cluster , and small disks containing stellar systems which are just forming. ... About APOD > . ...

... I happened to observe a surge of principle component analysis (PCA) and independent component analysis (ICA) applications in astronomy. ... Category: Algorithms , arXiv , Astro , Cross-Cultural , Data Processing , Jargon | ... Algorithms arXiv Astro Bad AstroStat Bayesian CHASC Cross-Cultural Data Processing Fitting Frequentist Galaxies gamma-ray High-Energy Imaging Jargon Job Languages MC MCMC Meta Methods Misc News Nuggets Objects Optical Physics Quotes Spectral Stars Stat Timing Uncertainty X-ray...

... 105Lawrence+ Nearly 1000 sources from the 5 GHz MIT-Green Bank (MG) survey have been observed with the VLA. ... About 1000 sources, selected as described in IIa from a prelimenary version of the MIT-GB I catalog, have been observed with VLA. ... About 20 sources observed at the VLA are within the MG sky area and above the 106 mJy completeness limit, even allowing for the large flux-density errors in the preliminary list, but do not appear in the MG catalog. ... 1 Source name in IAU B1950.0 format. ...

. Color composite images of seven LAEs found in this study as they appeared 13.1 billion years ago. This represents the combination of three filter images from Subaru Telescope. Red objects between two white lines are the LAEs. The LAEs of 13.1 billion years ago have a quite red color due to the effects of cosmic expansion on their component wavelengths of light. ICRR, University of Tokyo; NAOJ

... The fitting procedure will only converge to a unique solution if the components are linearly independent. ... The task calculates for each pair of component images and fails with an error if any is greater than 0.99. ... Hence components may be linearly independent in masked pixels yet still fail the test within the task. ... Finally, since the Poisson image values are necessarily all , negative values are not allowed in the model components. ...

From a bird's eye view of the ecliptic, it is clear that Pluto's orbit is more eccentric than any other planet's. Pluto's orbit appears to intersect Neptune's, and for a period of about 20 years Pluto is slightly closer to the sun than Neptune. ... The libration of Pluto's orbit is due to an exchange of angular momentum with Neptune. When Pluto is "catching up" to Neptune, it gains angular momentum at Neptune's expense. ...

Next: Ejectors in Massive Binary Previous: Artificial Galaxy: Full Matrix . The first version of the Scenario Machine was aimed especially at the simulation of massive binary star evolution. ... First, there is a large class of intermediate mass binaries (say, consisting initially of 8 + 5 solar masses) that can also produce NS and thus lead to the formation of a bright X-ray source. ... Next: Ejectors in Massive Binary Previous: Artificial Galaxy: Full Matrix Mike E. Prokhorov . ...