... QSO spectra in the ROSAT band are steeper than the background at harder energies, and furthermore at fluxes below 1E-14 ergs/(s cm?) the quasar source counts flatten off and are replaced by more numerous populations of relatively low red-shift objects, apparently Narrow Emission Line Galaxies (NELG). ... We extracted the luminosity function from ROSAT Deep Survey results, and extrapolated by a factor of 2 - 3 to account for changes expected in the harder XMM band. ...

Photon Scattering: Basic Principle of Photon Scattering . Audio Narration is available . No Scattering: Photon Source and Detector . ... For optical photons, scattering goes as wavelength to the -4 power. In the case of blue photons compared to red photons, this means that blue photons are about 10 times more likely to get scattered than red photons. ... Watch the blue photons scatter away from the detector . ... Interstellar dust make stars appear redder than they really are . ...

Next: Catalog Construction Up: Observations and Analysis Previous: Source Detections . ... It was assumed that the highest signal gives the most likely position of the source. ... Comparing the summed map with the maps from the individual energy ranges, the one which produced the smallest error box was chosen to represent the source position, as long as was greater than 4, a level chosen to reflect a reasonable degree of confidence in the detection. ...

... Data . ... In general, Dolphin finds good agreement with the Whitmore, Heyer, and Casertano results, and the longer baseline and more extensive data set used by Dolphin result in less scatter in the residuals. ... In these case the Dolphin corrections are larger than the Whitmore et al. corrections. ... Figure 1 shows the ratio of counts from a 14 second exposure of Omega Cen in August, 2000 to the counts in a 100 second exposure, vs. the Y position on the chip (WF2 in this case with gain=15). ...

... Apache HTTP Server Version 2.2 . ... Authorization based on file ownership . ... This module authorizes access to files by comparing the userid used for HTTP authentication (the web userid) with the file-system owner or group of the requested file. ... file-owner . ... The name of the system group that owns the file must be present in a group database, which is provided, for example, by mod_authz_groupfile or mod_authz_dbm , and the web-username must be a member of that group. ... Require file-group...

... Exposure Time Calculator (ETC) . Survey processing . ... VISTA is a 4-m class wide field survey telescope for the southern hemisphere, equipped with a near infrared camera (1.65 degree diameter field of view at VISTA's nominal pixel size) containing 67 million pixels of mean size 0.34 arcsec and available broad band filters at Z,Y,J,H,K s and a narrow band filter at 1.18 micron. A wide field visible camera, if constructed, could also be used on VISTA. ... Tile . ... ESO VISTA Public Surveys . ...

Peremennye Zvezdy", . ... Star Name: . GSC 3710-00312, USNO-A2.0 1425-04252279 . ... Variability type: . ... USNO-A2.0 1425-04252279 is located at the distance of 15?.7 from the X-ray source 1RXS J031707.9+572942, which is larger than the position error of the source (12?), but its hardness ratio HR1 = 0.03 0.29, typical of chromospherically active stars, and its character of variability allow us to assume that the star is related to the X-ray source. ... Eclipsing variability . Sine wave 1 . ...

... 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. ...

... Take a particularly simple signal: a cosine wave. ... Now, we are going to stretch and shrink the wavelet along the time axis (we assume the data is in the time domain), and at each time compare the shape of the signal to that of the wavelet. ... Figure 3: The wavelet (dotted line) is translated rela tive to the signal (solid line). ... Figure 4: The dashed line plots the `match' between the wavelets (dotted line) and the signal (solid line) as a function of time. ...

... Classes . ... This class gives Proxy to Fitting connection. ... Generic base class for least-squares fit. ... Internal Fitting_module classes and functions. ... The Fitting module holds various classes and functions related to fitting models to data. ... The above fitting problems can usually be solved by directly calling the fit() member function provided by one of the Fit classes above, or by gradually building the normal equation matrix and solving the normal equations ( solve() ). ...

SAI 175 anniversary . ... Moscow University . Search for in SAI Moscow University Search for in Russian astronomical resources . ... SAI Astronomical Databases . ... Browse SAI Software archive(ftp.sai.msu.su) . ASTRONET.RU - Russian Astronomical Network (available in translit also) . ... SAI Supernovae Research Group . ... Department of the Galaxy and Variable Stars (in Russian) . Sternberg Astronomical Institute Seminars . ... All-Russian Astronomical Olympiad (in Russian) . ...

... Astro 193 : HW 3 Ї NH = 3.07?0.02, 3.07?0.04, 3.18?0.04, 3.07?0.04, 2.93?0.06, 3.10?0.055, 2.90?0.035, 2.94?0.035, 2.74?0.025 = 1.84?0.01, 2.09?0.07, 2.06?0.015, 1.91?0.015, 1.92?0.015, 1.90?0.02, 2.28?0.15, 1.77?0.025, 1.91?0.025, 1.78?0.015, 1.84?0.015, 1.76?0.01 <NH> = 3.00 ; NH Ї Ї Ї Ї Ї = 0.15 < > = 1.92 ; = 0.17 WNH = 0.00165 ; BNH = 0.0179 ; TNH = 0.0215 ; dof NH = 9.39 W = 0.00253 ; B = 0.0236 ; T = 0.0281; dof = 13.29 <NH> T <> individual measurements with error bars B W inflation factor ...

... Problem 5. ... See figure 1 for the light curve of these narrow Nitrogen lines. ... Figure out the behaviour of each parcel of gas, and then add them all up to find the light curve. 5.4 (3pts) Using expression from problem 5.2, derive the expression for the time after SN explosion date, when the first light from the ionised ring reaches Earth. Using the expression from problem 5.2, derive the expression for the time after SN explosion date when the maximum brightness of the ring occurs. ...

... The standard science quicklook processing produces over a dozen sky maps at each downlink, and these maps are automatically searched for potential transient point sources. ... We have found that a heuristic modification of a formula derived by Li & Ma (1983) provides reasonably accurate estimates of p -values for point source detections even for very low p -value detections. ... Case 1u. The most straightforward approach uses the signal , where . ... To get a p -value, use . ...

Next: Identifications and Efficiency Up: THE DEEP X-RAY RADIO Previous: Source Classification . ... For some sources which did not have NVSS positions before the time of optical observations, arcsecond positions from the Texas survey (Douglas et al. 1996) and NED (typically based on VLA data) were used. ... All X-ray/radio sources without counterparts on the survey plates were imaged at either the KPNO 0.9m or the CTIO 0.9m telescopes. ... Previously Identified Sources . Sample Properties . ...

Next: SMUDGES Up: Minutes of the 1st Previous: Pilot Survey . ... The Jodrell Virgo survey is part of HIJASS and encompasses 4 X 8 degrees, fully sampled. ... This indicates that we should perhaps survey the outskirts of the cluster to look for low mass clouds. In the survey, objects were detected using a combination of by-eye method and automated routine. 28 detections of well known galaxies . ... Velocity distribution suggests infall or extension along the line of sight. ... Jon . ...

... The hotter the gas, the faster they move, and the more energy each of them holds. The free ions and electrons in a plasma behave the same way. Knowing the temperature of the high atmosphere of Earth, or that of the Sun, we can calculate energies expected of ions and electrons found there. However, ions and electrons actually observed in space are often much , much more energetic, and may move at a respectable fraction of the velocity of light (300,000 km/sec or 186,000 miles/sec). ...

STEP INTO THE BLUE - MEADE INSTRUMENTS PRODUCT GUIDE . ... Telescopes . LX850 Series . ... Superb optical performance coupled with time proven computerized pointing and tracking has made the LX200 ACF series a best-seller in the high-performance telescope class. ... Meade's revolutionary LS LightSwitchтДв series of telescopes use advanced technologies to do what no other consumer telescopes have done before: take all the hassle out of using a telescope. ... PST . ... Hard case for PST . ...

OptInt PmWiki : Pm Wiki / Wiki Word . A WikiWord is a set of two or more words run together, where the first letter of each word is capitalized. ... WikiWords are used as page titles in a wiki-based system . In some wikis (depending on the configuration of PmWiki), a valid link can be created by writing it as WikiWord. ... span.wikiword a.createlink { display:none; } span.wikiword a.createlinktext { border-bottom:none; text-decoration:none; color:inherit; } . ... Set in config.php : . ...

... To go through each file in the current directory and compare it with the same filename in another directory: #!/bin/sh # compare files to same file in directory "old" for i in * do echo $i: cmp $i old/$i echo done . ... Some examples of command substitution in for loops: #!/bin/sh # do something for all files in current # directory according to time modified for i in `ls -t` do ... done # do something for all non-fred files. for i in `cat filelist | ...