... The plots below show the gain ratio for all calibration sources plotted versus frequency. ... The telescope gain curves are made using a set of calibration sources selected by chris salter. ... Chris has fit these fluxes to the functional form: let y=log10(fluxJy) let x=log10(freqMhz) y= a0 + a1*x + a2*exp(-x) To compute a gain curve for a receiver we do a number of calibration scans using some of the calibration sources and then fit the gain as a function of azimuth and zenith angle. ...

... At high count rates, the video processing unit (VPU) of the FOC undercounts photon events, resulting in a nonlinear count rate. ... The FOC remains linear to much higher count rates for point sources than for uniform sources. ... Here, a uniform source is defined to be one in which the flux varies by less than +/- 10% on scales of 10 pixels, and the nonlinearity threshold is defined to be the count rate at which the FOC exhibits nonlinearity at the 10% level. ... 512 zoom x 1024 . ... 256 x 256 . ...

Thanks for your interest in accessing one of the higher education resources on the ASP website, and we hope you find it useful. ... So please help us by taking a minute to answer just a few questions below before downloading the resource. ... 4-year college instructor . ... NASA education/outreach/communications professional . ... With what type of course or program do you expect to use this resource? ... High school physics course . High school Earth science course . ... Skip to the resource . ...

... Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity . As imbalances are reached, the star is driven to find a new Energy source. ... Pressure and gravitational forces are equal, the star is stable and its core is sufficiently hot to fuse Hydrogen into Helium More about main sequence stars . ... The luminosity generated by the core fusion of Helium into Carbon is far greater than the shell luminosity associated with the fusion of Hydrogen into Helium. ...

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. ...

You can also see this page in Russian with using KOI8 (X Windows) or CP1251 (MS Windows) Cyrillic coding. The Laboratory supports the space TV experiments, mainly in the planetary exploration missions. ... Image Co-registration . ... PHOBOS mission - Martian satellites investigations. Phobos on the Martian limb, the image from Phobos-2 probe from 02/28/89. ... Russian Space Bulletin. ... Last modified at June,26 1997 Alexey Kuzmin: akuzmin@mx.iki.rssi.ru . Back to IKI home page ...

The process of determining the number and characteristics of sources in astronomical images is so fundamental to a large range of astronomical problems that it is perhaps surprising that no standard procedure has ever been defined that has well understood properties with a high degree of statistical rigour on completeness and reliability. ... In this analysis we present results from testing such algorithms as implemented in the SExtractor, Selavy (Duchamp), and sfind tools on simulated data. ...

... 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. ...

Next: Status of the BIMA Image Pipeline . ... We describe all the steps of the standard reduction including per pixel error propagation: Bias correction, treatment of bad pixels, flatfielding, and filtering of cosmic ray events. ... We build difference images via image convolution with a technique called OIS (optimal image subtraction, Alard & Lupton 1998), proceed with PSF-fitting, relative photometry on all pixels and finally apply an automatic detection of variable sources. ...

... Luminosity (L) · · · · A source's luminosity is the power that it emits in radiation. ... NB Astronomers often say `flux' when they mean `flux density' · SI units are Wm-2Hz -1 -26 filter · Also used are Jy 10 Wm-2Hz -1 E= РРРF d dA dt Specific Intensity, Surface Brightness (I) · Specific intensity (or surface brightness) is the power received (or emitted) per unit area per unit frequency per unit solid angle. ч F at surface of a spherical source = I · · Specific intensity is independent of distance...

... a) As source material for the high-school or college curriculum, especially in physics. astronomy and their history. (b) As a source of supplemental projects by high school students or by undergraduates. (c) As material for independent studies, In particular by motivated students who seek to know more about space . ... Those wishing to look up specific topics are advised to use the index file, accessible from the end of any "Exploration" file. ... files not listed and at other resource material. ...

... The stars examined here were primarily culled from two lists of X--ray sources in Orion. ... The second region is two degrees in extent east--west and ten degrees north--south with Orionis being near the northern edge. ... In the end, two main regions were chosen for monitoring: stars near Orionis and stars northwest of the belt of Orion. ... The PSPC identified 22 sources within 15 of Orionis in addition to the sources listed in Table 1 , giving a total of 85 X--ray sources in the Orionis region. ...

Orbit . ... The orbit of the RadioAstron provides four types of study: . rough images of radio sources with ultra-high angular resolution, using all baselines up to the radius of the apogee, that is much larger than Earth diameter; . ... high quality imaging of radio sources, with moderate resolution, by observing either with small projected base lines Earth-spacecraft, i.e. close to the orbital plane, or near the perigee. ... high accuracy orbit determination. ... Space Radio Telescope . ...

... Projects . ... High Energy Astrophysics department at IKI, Moscow, is carrying out research in various fields of X-ray astronomy: physical processes in the vicinity of compact sources of x-ray emission, x-ray observations using Russian space observatories MIR/KVANT and GRANAT, development of scientific instrumentation for the SPECTRUM-X-GAMMA mission and International Space Station (ISS), participation in the INTEGRAL project and observations on the RTT-150 optical telescope. 2016 IKI RAN ...

... The X-ray Sources of M31 . ... Credit: ROSAT , MPE , NASA Explanation: Just like our own Milky Way Galaxy , the nearest major galaxy M31 has many star systems spewing high energy radiation . ... Публикации с ключевыми словами: X-ray - рентгеновские источники - рентгеновские двойные - Рентгеновский телескоп - Андромеда . Публикации со словами: X-ray - рентгеновские источники - рентгеновские двойные - Рентгеновский телескоп - Андромеда . ... Рентгеновский телескоп Чандра . ...

... December 31, 1995 . The X-ray Sources of M31 . Credit: ROSAT , MPE , NASA . Explanation: Just like our own Milky Way Galaxy , the nearest major galaxy M31 has many star systems spewing high energy radiation . ... The X-ray sources in M31 occur in globular clusters , the spiral arms , and near the galaxy's center. ... M31 has more X-ray sources near its center than our Galaxy, and the reason for this is currently unknown. ... About APOD | ... NASA Technical Rep.: ...

. 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

Radio Interferometry Principles . Radio Interferometry Signal Processing . ... A radio interferometer consists of a pair of directional antennas that are tuned to receive radio emissions from a source in a desired RF band. ... The antennas are pointed at the radio source of interest and are set up to receive the signal and process it into a form suitable for transmission to the correlator. ... In connected element interferometry, the digital signal goes directly to the correlator. ...

... These sources are known from a previous study to be associated with dense gas and dust, and not associated with HII regions. All 11 sources were detected in HCO+, 9 in mm-continuum and 5 (out of 8 observed) in cm-continuum. The derived physical parameters confirm the high mass nature of these molecular clumps and suggest they are gravitationally bound. Molecular outflows were detected toward 6 sources, with flow masses and momenta much higher than in low-mass Young Stellar Objects (YSOs). ...

... The results of long-term monitoring of Gigahertz-Peaked Spectrum sources were found the statistically significant differences (0.05 significance level) in the high-frequency spectral index distribution between subgroups of galaxies and quasars. ... This can mean that the electron energy distribution for GPS galaxies is steeper than for GPS quasars. ... The first area corresponds to GPS-quasars that have statistically larger value of redfhift, second area corresponds to GPS-galaxies. ...