... Update to the COS FUV Dark Rates and Impact on ETC Calculations for Background Limited Observations . ... http://www.stsci.edu/~COS/fuv_darks/dark_vs_time_FUVA.png . http://www.stsci.edu/~COS/fuv_darks/dark_vs_time_FUVB.png . The ETC value for the COS/FUV detector dark rate is 4.0x10-6 counts/s/pixel for both segments. ... However, proposers considering COS/FUV observations of faint, background-limited targets may want to adjust their ETC calculations to use the lower background rate. ...

This diagram shows the six superimposed "layers" of the CSS table model. This diagram illustrates the algorithm for calculating a cell's final background. ... The diagram shows how, looking down on the six rectangles, one may compute the background color of each cell. ... A cell without a background color in the top layer is depicted as a "window" onto the lower layers, which give its final background color. ...

... Meta Index / Home Page / Description / Specifying source region shapes . When radiusstyle =`contour', the task calculates the source region shape as an elliptical locus which approximates the contour of the PSF at a given flux value. ... Clearly, in order to calculate the shape of such a flux contour, it is necessary firstly to normalize the PSF to the source brightness and secondly to determine the flux level (in `brightness' units per pixel) at which to find the contour. ...

... This paper describes the main algorithms used by the Einstein Level One processing to create the exposure masks and the background maps for Einstein IPC images, and how these algorithms were recreated in the IRAF environment. Our goal was to recreate the algorithms used by the Level One Processing to create exposure masks and background maps for Einstein Image Proportional Counter (IPC) data (cf. sections 2.5 and 2.7 of Harnden et al. ...

Next: AXAF Recipes Up: ROSAT HRI Recipes Previous: Quantum Efficiency Correction (a.k.a. For some observations, a significant amount of data may have been rejected during SASS processing because the background level was higher than the calculated threshold for rejection. ... REJECTED EVENTS . ... The recipe will allow the user to include rejected events in the generation of a new qpoe file and filter on the background level. ... This creates a qpoe file with standard + rejected events. ...

... The Cosmic X-Ray Background . ... Now, peering through a hole in the obscuring gas and dust of our own Milky Way Galaxy, the powerful orbiting XMM-Newton telescope has recorded this deep image of the x-ray sky , resolving some of the mysterious background into many faint individual sources. ... Do massive black holes reside in the hearts of all large galaxies? ... Publications with keywords: black hole - XMM-Newton - x-ray background - cosmic microwave background radiation - X-ray . ...

... 2000 November 9 . The Cosmic X-Ray Background . ... Notably, the faint sources tend to be green and blue, showing x-ray characteristics of huge amounts of material falling into massive black holes in very distant galaxies. ... The XMM-Newton results add to the growing consensus that they do and that, from across the universe , x-rays produced as matter feeds these black holes account for the cosmic x-ray background. ... About APOD | ...

... BOX= Area which needs to be flat fielded [whole map] OUTSET= Output Set/Subset(s) ORDER= Order of polynomial to be fitted to the map [1] highest allowed order is 21 ** RANGE= Give range of levels to include in fit: [all levels] Input consists of two values. ... Examples for the use of the RANGE= keyword: RANGE=2, 5 (IF 2<value<5 THEN include in fit ELSE value==>blank) RANGE=5, 2 (IF 2<value<5 THEN value==>blank ELSE include in fit) At the RANGE= keyword, the values -INF and INF can be input also. ...

... The cross entropy for this complex image is given by ( 16 ) and ( 17 ). ... Differentiating ( 31 ) with respect to and , we find the gradient of is given by . and upon differentiating once more we find the Hessian (curvature) matrix of has the form . ... and its Hessian matrix reads . ... From ( 16 ) and ( 17 ), we find the components of the gradient vector of the cross entropy are given by . ... Differentiating once more we find the components of the Hessian of the cross entropy to be given by . ...

T he Siding Spring Survey (SSS) is a Near-Earth Object search program that utilises the 0.5-m Uppsala Schmidt Telescope at Siding Spring Observatory, N.S.W., Australia. ... The mission of the Siding Spring Survey is to contribute to the inventory of near-earth objects (NEOs), or more specifically, the potentially hazardous asteroids (PHAs) and comets (PHOs) that may pose a threat of impact and thus harm to civilization. ... Based on the CSS Mission page . ... Siding Spring Survey Main Page . ...

Chromospheric line blanketing and the Hydrogen spectrum in M dwarfs C. I. Short J. G. Doyle We present non-LTE calculations of the H I spectrum in a grid of chromospheric models that represents a dM0 star in which the activity level ranges from quiescent to very active. ... We show that the predicted EW of Ly alpha in all models is reduced by as much as a factor of ~4, and that of H alpha in very active (dMe) stars is enhanced by a factor of about two by the inclusion of background line opacity. ...

Next: Bivariate polynomial interpolation Up: Echelle Spectra Previous: Removal of particle . The estimation of the background is one of the critical points in the reduction of echelle spectra for two reasons. ... diffuse light in the interorder space coming from adjacent orders. sky background spectrum . ... These locations are defined when performing the order definition (command DEFINE/ECHELLE or DEFINE/HOUGH ) and can be displayed by command LOAD/ECHELLE . ... Sky background definition . ...

... We can help students grasp the significance of Hubble's extremely keen eye, and learn a bit about angles and math in the process, with the following in-class activity. ... Looking through binoculars or telescopes allows us to magnify a small section of the sky. To measure sizes or distances in that small section, astronomers divide a degree into 60 smaller pieces called arcminutes, and further subdivide minutes into 60 smaller sections called arcseconds. ... 30 feet = . ... 36 seconds . ...

... Future seminars . P a s t seminars . ... Stochastic Particle Acceleration and the Problem of Background Plasma Overheating " . D.O. Chernyshov and V.A. Dogiel (P.N.Lebedev Institute of Physics) . ... It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by background plasma. ...

To run a process in the background as a job and carry on working add an (ampersand) at the end of the command line. ... The shell forks a child process to run the command and displays the job number ( [ n ] ) and the PID (Process IDentifier) number. ... If the command is likely to produce error messages you will need to redirect standard error. ... Do not run an interactive command that requires you to type something at the terminal as a background job. ... You will then have to kill its process . ...

Next: Reduce point data Up: Quick Guide Previous: Print form sheets Contents . You should reduce this data of type ``scan'' before anything else. ... Plot the background rate (four channels at a time) versus time. ... Use P ROCESS BG if you want to replace edited scans with an average value from other valid scans in the same channel. ... The reason for reducing the background data first is that average will not average the point data of a scan for which no background data exists. ...

... For a pulsar search observation, with the two polarizations averaged, a useful rule of thumb can be given for calculating the expected rms noise. If the rms noise, , is expressed in terms of the flux density of the target pulsar, then; . ... Robert Minchin 2012-02-22 ...

Class 1 Introduction, Background History of Modern Astronomy The Night Sky, Eclipses and the Seasons Kepler's Laws Newtonian Gravity General Relativity Matter and Light Telescopes Class 2 Solar System Characteristics Formation Exosolar Planets Class 3 Stars The S un Stellar Evolution of Low and High Mass Stars Deaths of Stars Exotic Stars Class 4 Galaxies Galaxy Classification Formation of Galaxies Galactic ... Low mass stars live and die differently than high mass stars. ...

... Tonight's Sky . ... The Magazine . ... Observing . ... Magazine . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Open cluster NGC 2818, spiral galaxy NGC 2964, and spiral galaxy NGC 2976 . ... Astronomy for Kids . ... Cosmic Adventures . ... cosmic microwave background . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email...

. To IUM main page . Algebraic groups and Lie groups(background) . Arithmetic group -what is it? . Cofinite and cocompact arithmetic subgroups. Constructions and examples. The Tamagava measure and local calculations in SL(2). Covolumes of the arithmetic subgroups in SL(2) (Borel Theorem). Congruence-subgroups and the congruence problem in SL(2)(Serre theorem). Hyperbolic 3- orbifolds and arithmetic groups in SL(2).