... One important issue for the spectral analysis with X-ray detectors is the treatment of background for extended sources. ... To deal with the particle background (more or less constant outside proton flares), one should assign weights to the reference event list and extract images or spectra using the same spectral or spatial (in detector coordinates) selection as the source. The original spatial selection (on the source) is usually applied to sky coordinates (not detector coordinates). ...

We have reviewed the characteristics of the extended red emission (ERE) as observed in many dusty astronomical environments, in particular, the diffuse interstellar medium of the Galaxy. ... We have compared the photoluminescence properties of a variety of carbon- and silicon-based materials proposed as sources for the ERE with the observationally established constraints. We found that silicon nanoparticles provide the best match to the spectrum and to the efficiency requirement of the ERE. ...

... 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...

... The HST uses an onboard model of its orbit to perform in real-time various control functions relating to spacecraft operations and observation support. ... New coefficients for the ephemeris are updated every other day, and are archived as FITS keywords for each HST observation data set. Using these coefficients,an observer can perform a variety of calibration and characterization calculations relating to the orbital position and velocity of the telescope. ...

Next: Principal Components Analysis Up: Multivariate Analysis Methods Previous: Multivariate Analysis Methods . Compared to the past, ever larger amounts of data are being collected in astronomy, and the rate will continue to accelerate in the next decades. It is therefore necessary to work on bigger samples if full advantage is to be taken of all accessible information. ... One way to work effectively on large samples is to apply, and if necessary to develop, suitable statistical methods. ...

... Classes . Files . ... File List . ... components . ... 00150 Bool set ( const SpectralElement in, const uInt which); 00151 00152 // Clear the list 00153 void clear (); 00154 00155 // Set a maximum size of the list 00156 void set ( const uInt nmax); 00157 00158 // Sort the list on the first parameter (i.e. peak value for Gaussian) 00159 void sort (); 00160 00161 // Convert to and from a Record (see details in SpectralElement) 00162 // group 00163 Bool fromRecord ( String errMsg, ...

Subject: Some useful data about gains, NFs compression points of Eddies box components . ... Gain: ~ 21 dB . ... 1 dB compression: + 6 dBm . ... 1dB compression point for this system is ~ +15 dBm. For a clean(i.e., very linear) signal, we recommend staying 10 dB or more below the 1dB compression point, putting the "peak linear power" at +5 dBm. ... Assuming an LNA + Mixer gain of ~ 35 dB and with + 8 dBm mixer compression point, any input - 27dBm will begin to saturate the mixer. ...

... 1994: . As a result of comparing the spectra of active solar regions from the observations with high spatial resolution in the microwave range at the RATAN-600 (the S-component) with a flare component observed at meter wavelengths on the VLA (USA) we revealed the presence of a strong and prolonged noise storm exactly where a weak decaying active region (with the presence of powerful active regions in the disk) is located. ... Archive . ...

... Gravitational wave search provides insights into galaxy evolution and mergers . ... galaxies . ... Globular cluster NGC 2808, elliptical galaxy NGC 2986, and the Sextans Dwarf . ... Open cluster NGC 2818, spiral galaxy NGC 2964, and spiral galaxy NGC 2976 . ... What are typical star-to-star distances in globular clusters compared to stellar distances in our region of the galaxy? ... RELATED TOPICS: GLOBULAR CLUSTERS . ... Get instant access to subscriber content on Astronomy.com! ...

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 . ...

... OEM OPTICAL COMPONENTS . ... Home Products OEM Optical Components . ... Objective, Plan Achromatic, 4 X 0.12, BF . ... Objective, Flatfield Achromatic, 20 X 0.40, BF . ... Objective, Flatfield Achromatic, 30 X 0.90, Iris, H2O Imm., ... Objective, Flatfield Achromatic, 60 X 1.00-0.70, Oil, Iris, BF . ... Objective, Flatfield Achromatic, 100 X 1.25, Oil, BF . ... Q-Plan™ Achromat Objective, 2.5 X 0.08, BF . ... Q-Plan™ Achromat Objective, 60 X 0.85, dry, BF . ... Eyepiece, Widefield, 10X, F.N. 18 . ...

The above image is a computer simulation of the distribution of mass in a Dark Matter dominated Universe. ... Structure (\eg density enhancements) clearly forms at the intersection of these filaments. ... What is Dark Matter? ... Testing for the presence of dark matter in the solar neighborhood now becomes an accounting problem The possible sources of this mass in the solar neighborhood are 1) luminous stars, 2) interstellar gas, 3) stellar remnants (mostly white dwarfs) and 4) dark matter: . ...

Text of these problems is available also in other languages : . ... What can one see in the Moon's sky more often - the Sun or the Earth? ... There are about of 250 millions of stars in the elliptical galaxy M32 (a satellite of Andromeda galaxy). ... The masses of Capella's components. ... You are proposed to estimate the masses of Capella's components, using our observational data. ... A galaxy's mass. ... Estimate the mass of FGC 1908 and compare it to the mass of our galaxy. ...

... This is possible at modest cost due to the low moments of inertia of the telescope and enclosure. ... This same performance will be achieved in higher winds when the telescope enclosure is facing away from the wind, or by using wind screens. ... The telescope system (MILT) will be remotely operable with an on-site operator's assistance by an astronomer located at one of the ARC member institutions. ... Mean Wind Speed . ... Offsets > 10 deg: 1 arc sec rms max . ... 5 sec max, tracking to tracking . ...

... 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. ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

Thesis grading criteria . ... Students should also take care to be specific about the work that they themselves did, as opposed to work done by collaborators and taken from the literature. ... The student has demonstrated some knowledge of the relevant background literature, but with serious gaps, and limited understanding. ... The student demonstrated that they had learned many of the relevant skills (which might include laboratory techniques, computer programming and statistical analysis). ...

. Comment on J1842+7946 . Comparing the brightnesses of the two main features seen in our 5 GHz image with higher frequency VLBI images available in the literature (at 8.4 GHz from the USNO database and at 15 GHz by Kellermann et al. (1998)), one can conclude that the NW component has a steeper spectrum since the SE one becomes relatively stronger as the observing frequency increases. VLBApls home page . Last modified: 16 Oct 2000

... Moscow, Russia E-mail: krivosheev@iki.rssi.ru Notes: · · The Monte Carlo method (s) is also called the statistical test method An innumerable number of processes can be listed the outcome of which is not determined and has probabilistic nature, but these processes obey statistical laws, so to obtain the result we have to make multiple similar tests, i.e. to use the MC method Because probabilistic processes are widely spread in nature, the MC ...

The VLTI Calibrator Selector Tool is a tool intended to assist in the selection of suitable interferometric calibrators for VLTI observations with MIDI and AMBER. It uses a model of the VLTI and its instruments to assess the fringe visibility, given the observed bandpass, the geometry, spectrum, and coordinates of the target and the time at which the observations are to be made. ... The tool offers an HTML/Java based interface and consists of two pages. ... The quality flag depends on LDD_chi2. ...