... The task first computes a background image in order to identify pixels that may be part of a source. The task uses two different algorithms for detecting ``point'' and ``extended'' sources. ... This is necessary because some faint ``point'' sources may have been missed by the point-source detection algorithm, but picked up by the extended-source detection algorithm. ... When the detection process is finished a check is made on extended sources to see if they can be split into two or more sources. ...

... 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 . ...

... Archives . ... Astronomers confront with various censored and truncated data. ... This area is called survival analysis . If your library has The American Statistician subscription and you are an astronomer handles censored or truncated data sets, this primer would be useful for briefly conceptualizing statistics jargon in survival analysis and for characterizing uncertainties residing in your data. Survival Analysis: A Primer by David A. Freedman . ... Chandra Blog . ... SAMSI AstroStat Prog. ...

The final hdf sequence of observations is listed in the phase-2 proposal. ... Observations run from 352:16 to 362:19. 10-sigma limits (20 pix area) Filter Nexp hours counts/s AB mag F300W 100 48.93 0.0148 27.47 F450W 62 36.52 0.0232 28.12 F606W 77 34.94 0.0370 28.71 F814W 49 34.86 0.0299 28.02 The limits are roughly 0.2 mag brighter than originally projected. 7.5e-7 erg cm-2 s-1 A-1 arcsec-2 (= 22.4 ABMAG in F814W ) Dark: maximum background 2100 sec Bright windows all go to F300W Dark ...

... PUL VLBI Analysis Center . ... Pulkovo EOP and Reference Systems Analysis Center (PERSAC) is located at the Pulkovo Observatory . ... Processing of VLBI , GPS, and optical observations aimed at analysis of the Earth rotation, station displacement, and celestial reference system. ... Celestial Pole Offset (CPO) and Free Core Nutation (FCN) . Four daily updated CPO and FCN series (models) are provided. ... File fcn1.dat contains the ZM1 FCN model with variable amplitude and phase. ...

My research interests are focussed on the theory and modelling of accretion processes as well as star and planet formation mechanisms. I am particularly interested in the stability properties of accretion discs, the generation of MHD turbulence and associated angular momentum transport, disk - planet interactions and the origin and characteristics of jets and winds from accreting systems . ... These results have been published in Salmeron & Wardle, 2005, M.N.R.A.S., 361: 45-69. ...

I was born in 1955, finished well-known 2nd school (mathematical) in Moscow, graduated at mathematical department of Moscow State University (MSU). My current positions are sci. researcher at Institute of Mechanics MSU and Network admin at Sternberg Astronomical Institute MSU. ... Hobbies: Anchient history, swimming, yachts, drinking vodka and good vine. ... Rambler in Russia: Some notes (in russian). ... For AstroNet users: see Netiquette in AstroNet (in Russian) for our administrative policy. ...

Next: Fitting of data Up: Extraction of Information Previous: Extraction of Information . For projects which perform statistical analysis on groups of objects, it is important to rely on an objective search method to extract them from the data frames. ... The simplest and fastest method is using a given level over a previously determined background value as the criterion to identify possible sources. ...

A very important stage in a story of formation of any new science is the shift from discussion of situation which are possible but do not occur in practice due to some reason to recognition of real phenomena of interest. ... We suggest to consider computer viruses as this new specific form of life which is coming in the contact with our form of life. ... Computer life has been created by human being, the role of independent evolution of computer viruses seems to be still negligible. ...

The "E-ALFA consortium" is a group of individuals interested in extragalactic spectral line programs usng ALFA and who are committed to coordinating efforts to the extent possible in order to maximize science return and program efficiency. ... The E-ALFA "coordinating committee" consists of representatives of E-ALFA consortium projects that have been granted telescope time or those in the development stage that have been endorsed by the E-ALFA consortium. ...

... Structure Detection in Low Intensity X­Ray Images using the Wavelet Transform Applied to Galaxy Cluster Cores Analysis Jean­Luc Starck and Marguerite Pierre CEA/DSM/DAPNIA F­91191 Gif­sur­Yvette cedex Abstract. ... Multi­resolution filtering methods based on the wavelet coe#cients detection are also discussed. Finally, using a set of ROSAT HRI deep pointings, the presence of small­scale structures in the central regions of clusters of galaxies is investigated. ... 1995; Rosati et al. ... 1996). ...

Next: Listing Image Values Up: Image Analysis Previous: Image Analysis . Task histo is a fairly commonly used task, giving a number of image statistics and a simple histogram. Apart from the input image (keyword in ), it can take a region of interest ( region ), a range to determine the histogram over ( range ), and the number of bins in the histogram ( nbins ). ... region . ... If you do not like histo , or you would like a PGPLOT plot of the histogram, you could use the task imhist instead. ...