- ID:
- ivo://nasa.heasarc/m16cxo
- Title:
- M 16 (Eagle Nebula) Chandra X-Ray Point Source Catalog
- Short Name:
- M16CXO
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Mechanisms regulating the origin of X-rays in young stellar objects and the correlation with their evolutionary stage are under debate. Studies of the X-ray properties in young clusters allow us to understand these mechanisms. One ideal target for this analysis is the Eagle Nebula (M 16), with its central cluster NGC 6611. At 1750 pc from the Sun, it harbors 93 OB stars, together with a population of low-mass stars from embedded protostars to disk-less Class III objects, with age <= 3 Myr. The authors study an archival 78 ks Chandra/ACIS-I observation of NGC 6611 and two new 80-ks observations of the outer region of M 16, one centered on the Column V and the other on a region of the molecular cloud with ongoing star formation. They detect 1755 point sources with 1183 candidate cluster members (219 disk-bearing and 964 disk-less), studying the global X-ray properties of M 16 and comparing them with those of the Orion Nebula Cluster. The authors also compare the level of X-ray emission of Class II and Class III stars and analyze the X-ray spectral properties of OB stars. Their study supports the lower level of X-ray activity for the disk-bearing stars with respect to the disk-less members. The X-ray luminosity function (XLF) of M 16 is similar to that of Orion, supporting the universality of the XLF in young clusters. Eighty-five percent of the O-type stars of NGC 6611 have been detected in X-rays. With only one possible exception, they show soft spectra with no hard components, indicating that mechanisms for the production of hard X-ray emission in O stars are not operating in NGC 6611. The determination of the absorption corrected X-ray luminosity (L<sub>X</sub>), as well as the plasma temperature (kT) and hydrogen column density (N<sub>H</sub>), requires the analysis of the X-ray spectra. The authors fit the observed spectra with thermal plasma (with both one and two temperatures) and power-law models. They use the APEC ionization-equilibrium thermal plasma code, assuming the sub-solar elemental abundances of Maggio et al. (2007, APJ, 660, 1462). The absorption was treated using the WABS model. The one-temperature (1T) thermal model was applied to all the sources with more than 25 counts, while the two-temperature (2T) thermal model was applied to each source with more than 80 counts. The power-law model has been applied to those sources with hard spectra for which the best-fit thermal model predicts a plasma temperature kT > 5 keV. When more than one model has been used for a given source, the authors chose the best model by the chi-squared probability and visual inspection of the spectrum. This table contains a description of the X-ray properties of 1754 sources (one less than stated in the abstract of the reference paper) derived from three Chandra/ACIS-I observations, together with a source classification based on the optical and infrared properties of each source. Data come from three ACIS-I observations (central or 'c', east or 'e', and north-east or 'ne') and many values are not averaged but presented for each observation as indicated by the parameter prefixes 'c_', 'e_', and 'ne_', respectively. Source detection has been performed with PWDetect, adopting a threshold corresponding to 10 spurious detections. The HEASARC eliminated the 3 parameters describing the plasma temperature of the second spectral component and its associated negative and positive errors for sources in the north-east observation, as these were blank for all entries in the original table as obtained from the CDS. This table was created by the HEASARC in March 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/753/117">CDS Catalog J/ApJ/753/117</a> file xraycat.dat. Some of the values for the alt_name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
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Search Results
- ID:
- ivo://nasa.heasarc/skyview/mellinger
- Title:
- Mellinger All Sky Mosaic: Red
- Short Name:
- MELLINGER
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This all sky mosaic was created by Axel Mellinger and is used in <i>SkyView</i> with his permission. A fuller description is available at the <a href="https://www.milkywaysky.com/">survey website</a>. <p> Between October 2007 and August 2009 a digital all-sky mosaic was assembled from more than 3000 individual CCD frames. Using an SBIG STL-11000 camera, 70 fields (each covering 40x27 degrees) were imaged from dark-sky locations in South Africa, Texas and Michigan. In order to increase the dynamic range beyond the 16 bits of the camera's analog-to-digital converter (of which approximately 12 bits provide data above the noise leve) three different exposure times (240s, 15s and 0.5 s) were used. Five frames were taken for each exposure time and filter setting. The frames were photometrically calibrated using standard catalog stars and sky background data from the Pioneer 10 and 11 space probes. the panorama has an image scale of 36"/pixel and a limiting magnitude of approximately 14. The survey has an 18 bit dynamic range. <p> The processing of these data used a custom data pipeline built using IRAF, Source Extractor and SWarp. <p> The data used here were converted to three independent RGB color planes of 8 bits each and provided to SkyView as a single 36000x18000x3 Cartesian projection cube. To allow users to efficiently sample data in a region of the sky, this cube was broken up into 2100x2100 pixel regions with a 50 pixel overlap between adjacent images. Tiles at the poles were 2100x2050. <p> In <i>SkyView</i> each color plane comprises a survey. The individual planes may be sampled as surveys independently as Mellinger-R, Mellinger-G and Mellinger-B. The color mosaics can be regenerated by creating an RGB image of all three surveys. Since <i>SkyView</i> may stretch the intensity values within each color, linear scaling and a minimum of 0 and maximum of 255 should be specified to keep the original intensity scalings. <p> The full spatial resolution data is used for images of less than 30 degrees on a side. If a user requests a larger region, data are sampled from a lower resolution 3600x1800x3 data cube. Please contact the survey author if you need to use the higher resolution data for larger regions. The Mellinger survey is only available in <i>SkyView</i> through the website. SkyView-in-a-Jar cannot access the underlying data. Provenance: Axel Mellinger. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/refnebulae
- Title:
- Merged Catalog of Reflection Nebulae
- Short Name:
- REFNEBULAE
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Several catalogs of reflection nebulae have been merged to create a uniform catalog of 913 objects. It contains revised coordinates, cross-identifications of nebulae and stars, as well as identifications with IRAS point sources. The HEASARC has endeavored to render all identifications of the nebulae in the various catalogs according to the styles recommended by the Dictionary of Nomenclature of Celestial Objects. This table was created by the HEASARC in October 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/399/141">CDS Catalog J/A+A/399/141</a> file table1.dat. This is a service provided by NASA HEASARC .
574. Messier Nebulae
- ID:
- ivo://nasa.heasarc/messier
- Title:
- Messier Nebulae
- Short Name:
- Messier
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Messier Catalog of bright, extended objects was compiled by the comet-hunter Charles Messier in the 18th century. It comprised a list of 110 objects which are mostly brighter than 10th magnitude and have angular sizes from 1 to 100 arcminutes. M 102 is now generally considered to be spurious, and the object so named was actually M 101. Hence this electronic version of the Messier Catalog contains only 109 objects. The objects in the Messier Catalog are predominantly star clusters in our Milky Way galaxy, with 29 of them being globular clusters, 27 open clusters; the rest are spiral galaxies (27), elliptical galaxies (11), diffuse and planetary nebulae (10), and miscellaneous objects (5). All of the objects in the Messier Catalog are north of -35 degrees declination. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m31stars
- Title:
- M 31 Field Brightest Stars Catalog
- Short Name:
- M31Stars
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Thie database table is a catalog of 11438 stars in the field of M31 and 8778 stars in 2 nearby "foreground" fields. It is based on a set of Tautenburg Schmidt plates in U, B, V, and R taken by van den Bergh. The range of visual magnitudes of stars is 11.5 < V < 20. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m31clustrs
- Title:
- M 31 Globular Cluster Candidates Catalog
- Short Name:
- M31/GC
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains a list of 288 globular cluster candidates and 132 miscellaneous objects found in a 70 arcminute square field centered on the M 31 (Andromeda) Galaxy. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/skyview/pmn
- Title:
- 4850 MHz Survey - GB6/PMN
- Short Name:
- PMN
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The 4850MHz data is a combination of data from three different surveys: Parkes-MIT-NRAO (PMN) Southern (-88&#176;; to -37&#176;; declination) and tropical surveys (-29&#176;; to -9&#176;; declination, and (86+87) Green Bank survey (0&#176;; to +75&#176;; declination). The data contains gaps between -27&#176;; to -39&#176;;, -9&#176;; to 0&#176;;, and +77&#176;; to +90&#176;; declination. The 4850MHz survey data were obtained by tape from J.J. Condon and are comprised of 576 images and are used by permission. Full information pertaining to these surveys are found in the references.<P> Provenance: NRAO, generated by J.J. Condon, J.J. Broderick and G.A. Seielstad, Douglas, K., and Gregory, P.C.. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/msxpsc
- Title:
- Midcourse Space Experiment (MSX) Point Source Catalog, V2.3
- Short Name:
- MSX
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the main catalog from Version 2.3 of the Midcourse Space Experiment (MSX) Point Source Catalog (PSC), which supersedes the previous version (1.2) that was released in 1999, and contains 100,000 more sources than the latter. The MSX PSC main catalog used to create this Browse table contains all the sources found in the Galactic Plane survey, and the primary high-latitude regions (the IRAS gaps regions, and the Large Magellanic Cloud). Note that this HEASARC table does not contain the MSX PSC supplementary catalogs, viz. the singleton catalog, the low-reliability catalog, or the minicatalogs for 19 selected regions. The principal objective of the astronomy experiments onboard the MSX satellite was to complete the census of the mid-infrared (4.2-25 micron or um) sky: namely, the areas missed by the IRAS mission (about 4% of the sky was not surveyed by IRAS), and the Galactic Plane (where the sensitivity of IRAS was degraded by confusion noise in regions of high source densities or of structured extended emission). The photometry is based on co-added image plates, as opposed to single-scan data, which results in improved sensitivity and hence reliability in the fluxes. Comparison with Tycho-2 positions indicates that the astrometric accuracy of the new catalog is more than 1" better than that in Version 1.2. The infrared instrument on MSX was named SPIRIT III; it was a 35-cm clear aperture off-axis telescope with five line scanned infrared focal-plane arrays of 18.3 arcseconds square pixels, with a high sensitivity (0.1 Jy at 8.3 um). The filter characteristics of the 6 spectral bands B1, B2, A, C, D and E are summarized below, where all wavelengths are in micron (µm): <pre> Band Center FWHM Points ---------------------------- B1 4.29 um 4.22 - 4.36 um B2 4.35 4.24 - 4.45 A 8.28 6.8 - 10.8 C 12.13 11.1 - 13.2 D 14.65 13.5 - 15.9 E 21.34 18.2 - 25.1 </pre> The MSX catalog names of the sources have been defined according to International Astronomical Union (IAU) conventions with a unique identifier combined with the position of the source. In this case, the MSX PSC V2.3 sources are named using the convention MSX6C GLLL.llll+/-BB.bbbb, where MSX6C denotes that this is MSX data run using Version 6.0 of the CONVERT software, and GLLL.llll+/-BB.bbbb gives the Galactic coordinates of the source. This database table was first created by the HEASARC in November 2002 and then updated in April 2005, based on the 11-Dec-2003 version of the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/V/114">CDS Catalog V/114</a> (specifically, the files gb_gt6.dat, gp_m05m2.dat, gp_m2m6.dat, gp_p05p2.dat, gp_p2p6.dat, and gp_pm05.dat which comprise the main catalog). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/msxuvpsc
- Title:
- Midcourse Space Experiment (MSX) Ultraviolet Point Source Catalog
- Short Name:
- MSXUVPSC
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Midcourse Space Experiment (MSX) Ultraviolet Point Source Catalog contains 47,283 point sources (the HEASARC notes that there actually 47,318 sources in this version of the table, 35 more than this number) from a set of 201 observations that surveyed approximately half the sky and from a set of 32 pointed observations toward specific targets. For each source, the catalog provides the position, UV magnitude and uncertainty in at least one of six filters, and, where possible, an identification of a nearby source from the SIMBAD database. If a nearby source is identified, its proximity to the MSX source, and if known, the spectral type and the B and V magnitudes of the SIMBAD object are also provided. There were 11,565 matches between MSX and SIMBAD objects (the HEASARC notes that there actually 11,662 matches in this version of the table, 97 more than this number), and the authors estimate the number of false identifications to be about 3%. The limiting fluxes differ from filter to filter, and range from 10<sup>-16</sup> erg/s/cm<sup>2</sup>/Angstrom for IUN4 to 7.8 x 10<sup>-12</sup> erg/s/cm<sup>2</sup>/Angstrom for IUW3. Because of variations among the observation sets, the catalog is not complete to the limiting magnitudes for the filters. The UV instrument on MSX was named UVISI (Mill et al., 1994, Journal of Spacecraft and Rockets, 31, 900 (1994JSpRo..31..900M in ADS); Carbary et al., 1994, Applied Optics, 33, 4201 (1994ApOpt..33.4201C in ADS)). The fields-of-view for the narrow-field and wide-field UV imagers were 1.46 x 1.19 degrees (detector pixels of 20.6" x 17.5") and 13.4 x 9.2 degrees (detector pixels of 3.12' x 2.27'), respectively. Four filters were used with the narrow-field imager (IUN) with effective wavelengths centered at 2480 Angstrom (IUN3), 2310 Angstrom (IUN4), 2230 Angstrom (IUN5), and 2930 Angstrom (IUN6). Two filters were used with the wide-field imager (IUW) and centered at 1320 Angstrom (IUW3) and 1560 Angstrom (IUW6). The HEASARC has removed from this table the parameter describing the objects' magnitude in the IUN5 filter as all of the sources had null values for this parameter. The CDS had previously made the following modifications compared to the version of the catalog as published in the reference paper: <pre> (1) The angular distances to the SIMBAD object (column "AngDist" of file catal.dat, called 'Offset' in this HEASARC table) was recomputed at CDS, the original values looking suspect. (2) In the course of this modification, 17 SIMBAD IDs were removed due to a large offset, most likely due to a sign error in the interpretation of SIMBAD's declination for IDs: 003341+001712 063054+004539 063211+005630 063754+003151 133358+001928 142557+003939 144541+002439 155701+004808 162743+004620 185855+003355 191033+004132 193004+005316 194525+001239 195040+004101 195717+001959 202844+005149 234324+000729 </pre> This table was created by the HEASARC in April 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/II/269">CDS Catalog II/269</a> file catal.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/globclust
- Title:
- Milky Way Globular Clusters Catalog (December 2010 Version)
- Short Name:
- GC
- Date:
- 14 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is the Catalog of Parameters for Milky Way Globular Clusters (December 2010 Version) that was compiled by William E. Harris of McMaster University. This is the first update since 2003 and the biggest single revision since the original version of the catalog published in 1996. The list now contains a total of 157 objects classified as globular clusters. Major upgrades have been made especially to the cluster coordinates, metallicities, and structural profile parameters, and the list of parameters now also includes the central velocity dispersion. This table contains basic parameters on distances, velocities, metallicities, luminosities, colors, and dynamical parameters for over 150 objects that are regarded as globular clusters in the Milky Way galaxy. Please acknowledge the use of this catalog in any published work you derive from it. The proper reference to the literature is the published paper (Harris, W.E. 1996, AJ, 112, 1487) which briefly describes the setup of the catalog. When you cite it in your text, please use "Harris 1996 (2010 edition)". The author would also greatly appreciate receiving any new information, in published or preprint form, which would help him to keep the list up to date (contact W. E. Harris at harris@physics.mcmaster.ca). A full discussion of the sources used in the creation of this catalog and of the parameters that it contains can be found in the file: <a href="http://physwww.mcmaster.ca/~harris/mwgc.ref">http://physwww.mcmaster.ca/~harris/mwgc.ref</a>. This table was originally ingested by the HEASARC circa 1995. It was last updated by the HEASARC in February 2014 based on an electronic version (dated December 2010) copied from the file <a href="http://physwww.mcmaster.ca/~harris/mwgc.dat">http://physwww.mcmaster.ca/~harris/mwgc.dat</a>. This is a service provided by NASA HEASARC .
