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Point source
About: Point source is a research topic. Over the lifetime, 5077 publications have been published within this topic receiving 94091 citations.
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TL;DR: In this paper, the total power and power spectrum due to a point source convecting at a uniform subsonic velocity along the axis of a round jet is calculated, where the source is a discrete frequency source in its own frame of reference.
58 citations
01 Oct 2003
TL;DR: The most recent version of the MSX point source catalog, version 2.3 as discussed by the authors, contains more than 100,000 sources that were not in the previous version, and most of the photometry was extracted from co-added images, as opposed to the single-scan data.
Abstract: : This Explanatory Guide describes Version 2.3 of the Midcourse Space Experiment (MSX) Point Source Catalog. The data calibration and processing are detailed, with particular attention to improvements over the initial published catalog, Version 1.2. The current catalog contains sources extracted from nearly all of the MSX astronomy experiments, including more than 100,000 sources that were not in the previous version. Most of the photometry was extracted from the co-added images, as opposed to the single-scan data, which significantly improves the signal-to-noise ratio of the point sources and hence their reliability. Comparison with Tycho-2 positions indicates that the astrometric accuracy of Version 2.3 is better by about I compared to Version 1.2. In addition to the Galactic Plane, Areas Missed by IRAS, and the Large Magellanic Cloud, which were included in Version 1.2, this release includes data from the Small Magellanic Cloud, eight nearby galaxies, and several molecular clouds and star forming regions.
58 citations
TL;DR: In this article, three different M31 disk fields, spanning a range of stellar populations, were observed by Chandra and the X-ray point source luminosity function (LF) of each region, and the LF of M31's globular clusters, were compared with each other and with the LF of the galaxy's bulge.
Abstract: Three different M31 disk fields, spanning a range of stellar populations, were observed by Chandra. We report the X-ray point source luminosity function (LF) of each region, and the LF of M31's globular clusters, and compare these with each other and with the LF of the galaxy's bulge. To interpret the results we also consider tracers of the stellar population, such as OB associations and supernova remnants. We find differences in the LFs among the fields, but cannot definitively relate them to the stellar content of the fields. We find that stellar population information, average and maximum source luminosities, X-ray source densities, and slopes of the LF are useful in combination.
58 citations
Patent•
13 Feb 2002
TL;DR: In this article, a point radiating source illuminates the aperture to cast an image onto the array, and a computer is employed to identify frequencies in the frequency domain to determine the image scale and shift along the detector array axis.
Abstract: A patterned mask is located at a distance from a linear detector array. A point radiating source illuminates the aperture to cast an image onto the array. A computer is employed to identify frequencies in the frequency domain to determine the image scale and shift along the detector array axis. Determination of the magnification of the aperture image is made employing frequency domain techniques, the aperture pattern being re-scaled to match that of the actual image, so that determination of pattern shift can be made. A first embodiment of the present invention has two variations, one of which employs the use of multiple single frequency components and phase methodology, the second of which uses multiple single frequency components as well as a variable frequency component. In a second embodiment, a composite image is also used except that only one single frequency component is used in addition to a non-periodic function.
57 citations
TL;DR: In this article, an association catalog is presented, listing the most likely counterpart for each RASS/BSC source, the probability that the NIR source and X-ray source are uniquely associated, and the probability Pnoid that none of the 2MASS/PSC sources are associated with the Xray source.
Abstract: The 18806 ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) X-ray sources are quantitatively cross-associated with near-infrared (NIR) sources from the Two Micron All Sky Survey Point Source Catalog (2MASS/PSC). An association catalog is presented, listing the most likely counterpart for each RASS/BSC source, the probability Pid that the NIR source and X-ray source are uniquely associated, and the probability Pnoid that none of the 2MASS/PSC sources are associated with the X-ray source. The catalog includes 3853 high quality (Pid>0.98) X-ray--NIR matches, 2280 medium quality (0.98>Pid>0.9) matches, and 4153 low quality (0.9>Pid>0.5) matches. Of the high quality matches, 1418 are associations that are not listed in the SIMBAD database, and for which no high quality match with a USNO-A2 optical source was presented for the RASS/BSC source in previous work. The present work offers a significant number of new associations with RASS/BSC objects that will require optical/NIR spectroscopy for classification. For example, of the 6133 Pid>0.9 2MASS/PSC counterparts presented in the association catalog, 2411 have no classification listed in the SIMBAD database. These 2MASS/PSC sources will likely include scientifically useful examples of known source classes of X-ray emitters (white dwarfs, coronally active stars, active galactic nuclei), but may also contain previously unknown source classes. It is determined that all coronally active stars in the RASS/BSC should have a counterpart in the 2MASS/PSC, and that the unique association of these RASS/BSC sources with their NIR counterparts thus is confusion limited.
57 citations