- ID:
- ivo://nasa.heasarc/orionffcxo
- Title:
- Orion Flanking Fields Chandra X-Ray Point Source Catalog
- Short Name:
- ORIONFFCXO
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of Chandra observations of two flanking fields (FFs) in Orion outside the Orion Nebula Cluster (ONC), in the form of a catalog of 417 sources, which includes X-ray luminosity, optical and infrared photometry, and X-ray variability information. 91 variable sources were found, 33 of which have flarelike light curves, and 11 of which have a pattern of a steady increase or decrease over a 10 hour period. The optical and infrared photometry for the stars identified as X-ray sources are consistent with most of these objects being pre-main-sequence stars with ages younger than 10 Myr. The two flanking fields in Orion were observed with the Advanced CCD Imaging Spectrometer (ACIS) detector on board the Chandra X-Ray Observatory. The north Orion flanking field (NOFF) is centered at a J2000 RA and Declination of 05:35:19, -04:48:15, which is about 36' (~5 pc, at a distance of 470 pc) north of the Trapezium cluster and was observed on 2002 August 26 with a total exposure time of 48.8 ks. The south Orion flanking field (SOFF), centered at a J2000 RA and Declination of 05:35:06, -05:40:48, which is about 17' (~ 2.5pc, at a distance of 470 pc) south of the Trapezium cluster, was observed on 2002 September 6 with a total exposure time of 47.9 ks. The data analysis for these observations was performed in the same manner as described in Ramirez et al. (2004, AJ, 127, 2659) for a similar observation of a field in NGC 2264, which should be consulted for the full details. (See also the help file for the HEASARC version of the catalog from the latter reference available at /W3Browse/chandra/ngc2264cxo.html ). This table was created by the HEASARC in February 2007 based on the CDS table J/AJ/128/787, files table1.dat, table3.dat and table4.dat. It does not include the results from the spectral analysis of 44 bright X-ray sources which were presented in Table 2 of the reference paper. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/onccxoopt
- Title:
- Orion Nebula Cluster Chandra HRC Optical Sample
- Short Name:
- ONCCXOOPT
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In the first of two companion papers on the Orion Nebula Cluster (ONC), the authors presented their analysis of a 63 ks Chandra HRC-I observation that yielded 742 X-ray detections within the 30' x 30' field of view. To facilitate their interpretation of the X-ray image, they compiled a multi-wavelength catalog of nearly 2900 known objects in the region by combining 17 different catalogs from the recent literature. They defined two reference groups: an infrared sample, containing all objects detected in the K band, and an optical sample comprising low-extinction, well-characterized ONC members. They showed for both samples that field object contamination is generally low. Their X-ray sources are primarily low-mass ONC members. The detection rate for optical sample stars increases monotonically with stellar mass from zero at the brown dwarf limit to ~100% for the most massive stars but shows a pronounced dip between 2 and 10 M<sub>sun</sub>. They determined L<sub>X</sub> and L<sub>X</sub>/L<sub>bol</sub> or all stars in their optical sample and utilized this information in their companion paper to study correlations between X-ray activity and other stellar parameters. In particular, the authors assembled an extensive catalog of known X-ray/optical/IR and radio objects that fell within the HRC FOV. In addition to their list of HRC sources and the Chandra source lists of Garmire et al. (2000, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/120/1426">CDS Cat. <J/AJ/120/1426></a>) and Schulz et al. (2001, CDS Cat. <J/ApJ/549/441>), they considered 14 catalogs from recent publications, producing a database of nearly 2900 distinct objects reported in at least one of the studies considered. A full list of references is given in the first column of Table 2 of the reference paper, along with a concise classification of the work and the referenced table number(s) from the original work. The authors' ONC optical sample is comprised of stars in the HRC FOV for which they have a mass estimate, whose values of the visual absorption A<sub>V</sub> are less than 3.0, and which are either confirmed proper motion members or have unknown proper motion (see Section 3.4.1 of the reference paper). For the 696 stars of this optical sample, this HEASARC table (the full version of Table 4 of the reference paper) lists sky position, mass, age, rotational period, Ca II line equivalent width, HRC basal count rate (see Section 5 of the reference paper), X-ray luminosity, and L<sub>X</sub>/L<sub>bol</sub> (see Sections 4 and 5 of the reference paper). This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/582/382, file table4.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/onccxoxray
- Title:
- Orion Nebula Cluster Chandra HRC X-Ray Point Source Catalog
- Short Name:
- ONCCXOXRAY
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In the first of two companion papers on the Orion Nebula Cluster (ONC), the authors presented their analysis of a 63 ks Chandra HRC-I observation that yielded 742 X-ray detections within the 30' x 30' field of view. To facilitate their interpretation of the X-ray image, they compiled a multi-wavelength catalog of nearly 2900 known objects in the region by combining 17 different catalogs from the recent literature. They defined two reference groups: an infrared sample, containing all objects detected in the K band, and an optical sample comprising low-extinction, well-characterized ONC members. They showed for both samples that field object contamination is generally low. Their X-ray sources are primarily low-mass ONC members. The detection rate for optical sample stars increases monotonically with stellar mass from zero at the brown dwarf limit to ~100% for the most massive stars but shows a pronounced dip between 2 and 10 M<sub>sun</sub>. They determined L<sub>X</sub> and L<sub>X</sub>/L<sub>bol</sub> or all stars in their optical sample and utilized this information in their companion paper to study correlations between X-ray activity and other stellar parameters. In particular, the authors assembled an extensive catalog of known X-ray/optical/IR and radio objects that fell within the HRC FOV. In addition to their list of HRC sources and the Chandra source lists of Garmire et al. (2000, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/120/1426">CDS Cat. <J/AJ/120/1426></a>) and Schulz et al. (2001, CDS Cat. <J/ApJ/549/441>), they considered 14 catalogs from recent publications, producing a database of nearly 2900 distinct objects reported in at least one of the studies considered. A full list of references is given in the first column of Table 2 of the reference paper, along with a concise classification of the work and the referenced table number(s) from the original work. The HRC on board the Chandra X-Ray Observatory (Weisskopf et al., 2002PASP..114....1W) observed the ONC for 63.2ks on 2000 February 4. The pointing (R.A. = 5h 35m 17s, DE=-5{deg} 23' 16" (J2000.0)) was chosen to place the Trapezium region and the bright O star Theta<sup>1</sup> Ori C in the center of the field of view (FOV). A good fraction of the ONC region was included in the 30' x 30' HRC FOV. This HEASARC table lists the properties of the 742 X-ray sources detected in this observation as presented in the full version of Table 1 of the reference paper. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/582/382, file table1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/oriysoir
- Title:
- Orion Nebula YSO IR Properties
- Short Name:
- ORIYSOIR
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The origin and evolution of the X-ray emission in very young stellar objects (YSOs) are not yet well understood because it is very hard to observe YSOs in the protostellar phase. Using COUP data, the authors studied in their reference paper the X-ray properties of stars in the Orion Nebula Cluster (ONC) in different evolutionary classes: luminosities, hydrogen column densities N<sub>H</sub>, effective plasma temperatures, and time variability were compared to understand if the interaction between the circumstellar material and the central object can influence the X-ray emission. They have assembled the deepest and most complete photometric catalog of objects in the ONC region from the UV to 8 microns (µm) using data from the HST Treasury Program; deep and almost simultaneous UBVI and JHK images taken, respectively, with WFI at ESO 2.2m and ISPI at CTIO 4m telescopes; and Spitzer IRAC imaging. They selected high-probability candidate Class 0-I protostars, a sample of "bona fide" Class II stars, and a set of Class III stars with IR emission consistent with normal photospheres. Their principal result is that Class 0-Ia objects are significantly less luminous in X-rays, in both the total and hard bands, than the more evolved Class II stars with mass larger than 0.5M_{sun}_; the latter show X-ray luminosities similar to those of Class 0-Ib stars. This table contains the JHK and IRAC data, as well as the protostar classifications, for 398 ONC YSOs. This online catalog was created by the HEASARC in October 2010 based on the machine-readable versions of Tables 2, 3, 4 and 5 from the reference paper which were obtained from the CDS (their catalog J/ApJ/677/401). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/oso8alc
- Title:
- OSO8 A Detector Lightcurves
- Short Name:
- OSO8ALC
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database accesses the FITS lightcurves obtained from the A detector part of the GSFC Cosmic X-ray Spectroscopy experiment (GCXSE) on board OSO8. The Orbiting Solar Observatory-I (OSO-8) was launched on 21 June 1975 into a 550 km circular orbit at 33 degrees inclination. While the primary objectives of the mission were solar in nature, there were 3 detectors (the GCXSE detectors A, B and C) which had exclusively non-solar objectives. The energy band was 2-60 keV for the A and C detector and 2-20 keV for the B detector. The spacecraft structure consisted of a rotating cylindrical base section called the "wheel" and a non-spinning upper section called the "sail". The GCXSE detectors were mounted in the rotating wheel and their fields-of-view were either aligned to the spin axis (B and C) or at small angles to it (A), hence they always viewed the portion of the sky at right angles to the earth-sun line. The GCXSE detectors obtained data until late September 1978. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/oso8bclc
- Title:
- OSO8B&CDetectorLightcurves
- Short Name:
- OSO8BCLC
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- OSO8 B&C Detector Lightcurves This is a service provided by NASA HEASARC .
647. OSO8 GCXSE Raw PHA
- ID:
- ivo://nasa.heasarc/oso8pharaw
- Title:
- OSO8 GCXSE Raw PHA
- Short Name:
- OSO8PHARAW
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Orbiting Solar Observatory-I (OSO-8) was launched on 21 June 1975 into a 550 km circular orbit at 33 degrees inclination. Data were obtained from the mission until late September 1978. The spacecraft structure consisted of a rotating cylindrical base section called the "wheel" and a non-spinning upper section called the "sail". While the primary objectives of the mission were solar in nature, there were 3 detectors, the GSFC Cosmic X-ray Spectroscopy experiments (GCXSE detectors A, B, and C), mounted in the rotating wheel which had exclusively non-solar objectives. Their fields-of-view were either aligned to the spin axis or at small angles to it, hence they always view the portion of the sky at right angles to the earth-sun line. This database accesses the pha FITS datafiles for the A, B, and C GCXSE detectors. Data was accumulated every quarter of a rotation period (~2.56 s) for the A detector and every 40.96 s for the B and C detectors in the 2-60 keV energy band. This is a service provided by NASA HEASARC .
648. OSO8 GCXSE Raw Rates
- ID:
- ivo://nasa.heasarc/oso8rtraw
- Title:
- OSO8 GCXSE Raw Rates
- Short Name:
- OSO8RTRAW
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Orbiting Solar Observatory-I (OSO-8) was launched on 21 June 1975 into a 550 km circular orbit at 33 degrees inclination. Data were obtained from the mission until late September 1978. The spacecraft structure consisted of a rotating cylindrical base section called the "wheel" and a non-spinning upper section called the "sail". While the primary objectives of the mission were solar in nature, there were 3 detectors, the GSFC Cosmic X-ray Spectroscopy experiments (GCXSE detectors A, B and C), mounted in the rotating wheel which had exclusively non-solar objectives. Their fields-of-view were either aligned to the spin axis or at small angles to it, hence they always view the portion of the sky at right angles to the earth-sun line. This database accesses the raw rates FITS datafile for the A, B and C GCXSE detectors, accumulated every 160 ms in the 2-60 keV energy band. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/dncvobcat
- Title:
- Outburst Catalog of Dwarf Novae-type and Other Cataclysmic Variables
- Short Name:
- DNCVOBCAT
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This outburst catalog contains a wide variety of observational properties for 722 dwarf nova-type (DN) cataclysmic variables (CVs) and 309 CVs of other types from the Catalina Real-time Transient Survey (CRTS). In particular, it includes the apparent outburst and quiescent V-band magnitudes, duty cycles, limits on the recurrence time, upper- and lower-limits on the distance and absolute quiescent magnitudes, color information, orbital parameters, and X-ray counterparts. These properties were determined by means of a classification script presented in the reference paper. The DNs in the catalog show a correlation between the outburst duty cycle and the orbital period (and outburst recurrence time), as well as between the quiescent absolute magnitude and the orbital period (and duty cycle). This is the largest sample of dwarf nova properties collected to date (2016). Besides serving as a useful reference for individual systems and a means of selecting objects for targeted studies, it will prove valuable for statistical studies that aim to shed light on the formation and evolution of cataclysmic variables. The CRTS identifies transients in the data from the Catalina Sky Survey (Larson et al. 1998, BAAS, 30, 1037; 2003, BAAS, 35, 982), a photometric survey that searches for Potentially Hazardous Asteroids and Near Earth Objects. Three sub-surveys constitute the Catalina Sky Survey, namely the original CSS (Catalina Schmidt Survey), the MLS (Mt Lemmon Survey) based in Arizona, and the SSS (Siding Spring Survey) in Australia, which ended on 2014 July 5. The field of view and typical limiting magnitude for each survey (at ~30 s integrations) are 8.2 degrees and V~19.5 mag for the CSS, 1.1 degrees and V~21.5 mag for the MLS, and 4 degrees and V~19 mag for the SSS. Together, these surveys cover 30, 000 deg<sup>2</sup> between -70 and +70 degrees Declination (see Drake et al. 2014, MNRAS, 441, 1186 for more details). The entire zone within 15 Degrees of the Galactic Plane is avoided due to overcrowding, as are the Magellanic Clouds. The properties of the cataclysmic variables in this catalog are derived from the long-term optical light curves from the CRTS, as well as magnitudes, fluxes and orbital parameters from the SDSS, 2MASS, UKIDSS, ROSAT, Chandra, XMM and WISE catalogs, and from the Catalog of Cataclysmic Binaries, Low-Mass X-Ray Binaries and Related Objects (RKCat: Ritter and Kolb 2003, A&A, 404, 301, available at the HEASARC as the RITTERCV, RITTERLMXB and RITTERRBIN tables). This table was created by the HEASARC in October 2017 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/456/4441">CDS catalog J/MNRAS/456/4441</a> file catalog.dat. . This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ovro31ghz
- Title:
- Owens Valley Radio Observatory 40-m 31-GHZ Radio Source Catalog
- Short Name:
- OVRO31GHZ
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The 100m Robert C. Byrd Green Bank Telescope (GBT) and the 40m Owens Valley Radio Observatory (OVRO) telescope have been used to conduct a 31-GHz survey of 3165 known extragalactic radio sources over 143 deg<sup>2</sup> of the sky. Target sources were selected from the NRAO VLA Sky Survey (NVSS) in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4-GHz flux densities of 3-10 mJy. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4 - 31 GHz spectral indices of these sources, the authors find a mean 31 - 1.4 GHz flux ratio of 0.110 +/- 0.003 corresponding to a spectral index alpha = -0.71+/-0.01 (S<sub>nu</sub> ~ nu<sup>alpha</sup>); 9.0% +/- 0.8% of the sources have alpha > -0.5 and 1.2% +/- 0.2% have alpha > 0. By combining this spectral-index distribution with 1.4GHz source counts, the authors predict 31-GHz source counts in the range 1 mJy <S<sub>31</sub> < 4 mJy, N(>S<sub>31</sub>) = (16.7+/-1.7)deg<sup>-2</sup>(S<sub>31</sub>/1mJy)<sup>(-0.80+/-0.07)</sup>. In this study, the authors present a detailed characterization of the impact of the discrete source foreground on arcminute-scale 31-GHz anisotropy measurements based upon two observational campaigns. The first campaign (the results of which are given in this table) was carried out with the OVRO 40m telescope at 31 GHz from 2000 September through 2002 December. The second campaign (the results of which are given in the GBT31GHZ table) used the GBT from 2006 February to May. A companion paper (Sievers et al. 2009arXiv0901.4540S) presents the five-year CBI total intensity power spectrum incorporating the results of the point-source measurements discussed here. Reported error bars include a 10% and 5% rms gain uncertainty for GBT and OVRO measurements, respectively. Sources detected at greater than 4 sigma at 31 GHz are flagged (detection_flag = 'Y'); for this calculation, the random gain uncertainty was excluded. In all 3165 sources were observed. The GBT catalog (the HEASARC GBT31GHZ table) contains 1490 sources. Of the 2315 useful OVRO observations many of the non-detections (and a few detections) were superceded by more sensitive GBT observations; the OVRO catalog contained in the present table therefore contains data on 1675 sources. The detection rate of the OVRO measurements was 11%, and that of the GBT measurements 25%. In all, 18% of the sources were detected at 31 GHz. This table was created by the HEASARC in June 2012 based on CDS Catalpog J/ApJ/704/1433 file table2.dat. This is a service provided by NASA HEASARC .
