- ID:
- ivo://nasa.heasarc/galcencxo
- Title:
- Galactic Center Chandra X-Ray Point Source Catalog
- Short Name:
- GALCENCXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 9017 X-ray sources identified in Chandra observations of a 2 degrees by 0.8 degrees field around the Galactic center. This enlarges the number of known X-ray sources in the region by a factor of 2.5. The catalog incorporates all of the ACIS-I observations as of 2007 August, which total 2.25 Ms of exposure. At the distance to the Galactic center (8 kpc), we are sensitive to sources with luminosities of 4 x 10<sup>32</sup> erg s<sup>-1</sup> (0.5-8.0 keV; 90% confidence) over an area of 1 degree<sup>2</sup>, and up to an order of magnitude more sensitive in the deepest exposure (1.0 Ms) around Sgr A*. The positions of 60% of the sources are accurate to <1 arcsecond (95% confidence), and 20% have positions accurate to <0.5 arcsec. The authors search for variable sources, and find that 3% exhibit flux variations within an observation, and 10% exhibit variations from observation-to-observation. They also find one source, CXOUGC J174622.7-285218, with a periodic 1745 s signal (1.4% chance probability), which is probably a magnetically accreting cataclysmic variable. The authors compare the spatial distribution of X-ray sources to a model for the stellar distribution, and find 2.8 sigma evidence for excesses in the numbers of X-ray sources in the region of recent star formation encompassed by the Arches, Quintuplet, and Galactic center star clusters. These excess sources are also seen in the luminosity distribution of the X-ray sources, which is flatter near the Arches and Quintuplet than elsewhere in the field. These excess point sources, along with a similar longitudinal asymmetry in the distribution of diffuse iron emission that has been reported by other authors, probably have their origin in the young stars that are prominent at a galactic lonitude ~ 0.1 degrees. This tables was designed to be inclusive, so sources of questionable quality are included, according to the authors. For instance, 134 sources have net numbers of counts in the 0.5-8.0 keV band that are consistent with 0 at the 90% confidence level. These sources are only detected in a single band and are presumably either very hard or very soft, detected in single observations because they were transients, or detected in stacked observations with wvdecomp at marginal significance. The authors have chosen to include them because they passed the test based on Poisson statistics from Weisskopf et al. (2007, ApJ, 657, 1026). The observations which were used to generate the source list herein tabulated are listed in Table 1 of the reference paper. This HEASARC table GALCENCXO supercedes and replaces the previous HEASARC tables CHANGALCEN and CHANC150PC, which were based on Muno et al. (2003, ApJ, 589, 225) and Muno et al. (2006, ApJS, 165, 173), respectively. This table was created by the HEASARC in March 2009 based on the machine-readable versions of Table 2, 3 and 4 from the paper which were obtained from the electronic ApJ website. The information on short-term variability given in Table 5 of the reference paper was not included in this HEASARC table, notice. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/galccxonid
- Title:
- Galactic Center Chandra X-Ray Source Near-IR Counterparts
- Short Name:
- GALCCXONID
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2 degrees x 0.8 degrees of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. The authors have cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10-sigma limiting flux of K<sub>s</sub> <= 15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, they defined red and blue sources as those which have H - K<sub>s</sub> >= 0.9 and < 0.9 mag, respectively. The authors find that 5.8% =/- 1.5% (2 sigma) of the hard X-ray sources have real infrared counterparts, of which 228 +/- 99 are red and 166 +/- 27 are blue. The red counterparts are probably comprised of Wolf-Rayet and O stars, high-mass X-ray binaries, and symbiotic binaries located near the Galactic center. Foreground X-ray binaries suffering intrinsic X-ray absorption could be included in the sample of blue infrared counterparts to hard X-ray sources. The authors also find that 39.4% +/- 1.0% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ~20 red counterparts to hard X-ray sources near the Sagittarius B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in their catalog, the authors derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis. These data are included in this catalog and will serve spectroscopic surveys to identify infrared counterparts to X-ray sources near the Galactic center. This table was created by the HEASARC in October 2009 based on the electronic version of Table 3 from the reference paper which was obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gwsstrpcxo
- Title:
- Groth-Westphal Strip Chandra X-Ray Point Source Catalog
- Short Name:
- GWSSTRPCXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the optical and X-ray spectral properties of the sources detected in a 200-ks Chandra observation of part of the Groth-Westphal Strip (GWS) region, using the ACIS-I instrument. The authors present a relatively simple method for the detection of X-ray point sources and the calculation of limiting sensitivities, which they argue is at least as sensitive and more self-consistent than previous methods presented in the literature. A total of 158 distinct X-ray sources are included in this point-source catalogue in the ACIS-I area with a threshold Poisson detection probability of 4 x 10<sup>-6</sup>. The number counts show a relative dearth of X-ray sources in this region. A wealth of optical photometric and spectroscopic data are available in this field providing optical identifications and redshift determinations for the X-ray population. The optical photometry and spectroscopy used here are primarily from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey with additional redshifts obtained from the literature. These are complemented with the deeper (r ~ 26 mag) multiwaveband data (ugriz) from the Canada-France-Hawaii Telescope Legacy Survey to estimate photometric redshifts and to optically identify sources fainter than the DEEP2 magnitude limit (R<sub>AB</sub> ~ 24.5 mag). The authors focus their study on the 2 - 10 keV selected sample comprising 97 sources to the flux limit ~8 x 10<sup>-16</sup> erg/s/cm<sup>2</sup>, this being the most complete in terms of optical identification rate (86 per cent) and redshift determination fraction (63 per cent; both spectroscopic and photometric). Chandra observed the GWS, which is part of the Extended Groth Strip (EGS) region, on three separate occasions between 2002 August 11 and 22, using ACIS-I as the prime instrument. The S2 and S3 chips of the ACIS-S array were also operating during the observation, but as these are far off-axis their data are not considered further. The sequence number identifying the observations was 900144 and the three observation ID numbers (3305 on 2002-08-11, 4357 on 2002-08-12, and 4365 on 2002-08-21). This table was created by the HEASARC in July 2007 based on the merger of <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/356/568">CDS Catalog J/MNRAS/356/568</a> file table3.dat and <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/371/221">CDS Catalog J/MNRAS/371/221</a> file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hperseicxo
- Title:
- H Persei Chandra X-Ray Point Source Catalog
- Short Name:
- HPERSEICXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from a Chandra/ACIS-I observations of the massive ~ 13-14 Myr-old cluster, h Persei, part of the famous Double Cluster (h and Chi Persei) in Perseus. Combining the list of 330 Chandra-detected sources with new optical/IR photometry and optical spectroscopy reveals ~ 165 X-ray bright stars with V <~ 23. Roughly 142 have optical magnitudes and colors consistent with cluster membership. The observed distribution of X-ray luminosity L<sub>x</sub> peaks at L<sub>x</sub> ~ 10<sup>30.3</sup> erg s<sup>-1</sup> and likely traces the bright edge of a far larger population of ~ 0.4-2 M<sub>sun</sub> X-ray active stars. From a short list of X-ray active stars with IRAC 8-micron excess from warm, terrestrial zone dust, the authors derive a maximum X-ray flux incident on forming terrestrial planets. Although there is no correlation between X-ray activity and IRAC excess, the fractional X-ray luminosity correlates with optical colors and spectral type. By comparing the distribution of L<sub>x</sub>/L<sub>star</sub> versus spectral type and (V-I) in h Per with results for other 1-100 Myr-old clusters, the authors show that stars slightly more massive than the Sun (>~ 1.5 M<sub>sun</sub>) fall out of X-ray saturation by ~ 10-15 Myr. Changes in stellar structure for >~ 1.5 M<sub>sun</sub> stars likely play an important role in this decline of X-ray emission. Chandra observations of h Persei were taken with a 41.1 ks exposure on 2004 December 2, (Obs. ID 5407; Sequence Number 200341) with the ACIS detector (chips 0, 1, 2, 3, 6, and 7). The data were obtained in dithered, timed mode, with a frametime of 3.2 s. On-board event rejection and event telemetry was in the VFAINT mode. The field was centered on RA(2000) = 2h19m00s, Dec(2000) = 57d07'12", close to the center of h Persei from Bragg & Kenyon (2005, AJ, 130, 134) (RA(2000) = 2h18m56.4s, Dec(2000) = 57d08'25") and observed at a roll angle of 229 degrees. The data were not registered to an astrometric reference frame (e.g., Two Micron All Sky Survey, 2MASS). The ACIS-I field covers a 17' x 17' area. This table was created by the HEASARC in March 2009 based on the electronic versions of Tables 1 and 2 from the paper which were obtained from the Astronomical Journal web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ic1396acxo
- Title:
- IC1396A&Trumpler37ClusterChandraX-RayPointSourceCatalog
- Short Name:
- IC1396ACXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Rich, young stellar clusters produce H II regions whose expansion into the nearby molecular cloud is thought to trigger the formation of new stars. However, the importance of this mode of star formation is uncertain. This investigation seeks to quantify triggered star formation (TSF) in IC 1396A (aka the Elephant Trunk Nebula), a bright-rimmed cloud (BRC) on the periphery of the nearby giant HII region IC 1396 produced by the Trumpler 37 cluster. X-ray selection of young stars from Chandra X-ray Observatory data is combined with existing optical and infrared surveys to give a more complete census of the TSF population. Over 250 young stars in and around IC 1396A are identified; this doubles the previously known population. A spatio-temporal gradient of stars from the IC 1396A cloud towards the primary ionizing star HD 206267 is found. The current project consists of two Chandra-ACIS X-ray observations of IC 1396A, a Guaranteed Time observation (ObsID No. 11807 obtained on 2010 March 31; PI: Garmire) and a Guest Observer observation (ObsID No. 10990 obtained on 2010 June 9; PI: Getman). Both observations were pointed at the head of the globule but had different roll angles. For each observation, the authors considered only results arising from the imaging array (ACIS-I) of four abutted 1024 x 1024 pixel front-side illuminated charge-coupled devices (CCDs) covering about 17 x 17 arcmin<sup>2</sup> on the sky, Similar to the Chandra catalog of X-ray sources in the Carina Nebula (Broos et al. 2011, ApJS, 194, 2), this list of candidate sources in IC 1396A is trimmed to omit sources with fewer than 3 total source counts (the sum of the net counts and the background counts, NC + BC < 3) and the probability for being a background fluctuation greater than 1% (prob_no_src > 0.01). The final catalog comprises 415 X-ray sources, roughly half of which sources are extragalactic with extremely optically faint counterparts (Section 3.2 of the reference paper), and the rest are young stars associated with the Trumpler 37 and IC 1396A star-forming regions. UVR<sub>c</sub> I<sub>c</sub> observations were carried out with the 1.2-m telescope at the Fred Lawrence Whipple Observatory (FLWO), using the 4Shooter CCD array, between 2000 September and 2002 September. 4Shooter is an array of four CCDs, covering a square of 25 arcminutes on the side. Two 4Shooter fields were taken to cover an ~45 x 25 arcmin<sup>2</sup> area centered on the star HD 206267. The FLWO fields contain the whole ACIS field, except for a small gap in between the four CCDs of 4Shooter. All but a few Chandra stars were observed in 2000 September. UVR<sub>J</sub> I<sub>J</sub> observations of Trumpler 37/IC 1396A were obtained in service mode during three nights in 2007 June 9-11 using the wide-field camera, LAICA, mounted on the 3.5-m telescope in Calar Alto, Spain. LAICA is a 2 x 2 mosaic of four CCDs, each covering a 15.3 x 15.3 arcmin<sup>2</sup> field of view (FOV) with a large gap of 15.3 x 15.3 arcmin<sup>2</sup> in between. The project combines four LAICA pointings covering an ~45 x 45 arcmin<sup>2</sup> area around HD 206267, including nearly the entire ACIS field. The Spitzer observation was obtained on 2003 December 20 with the IRAC detector in all four IRAC channels (3.6, 4.5, 5.8 and 8.0 micron). Two adjacent fields subtending ~37 x 42 arcmin<sup>2</sup> in channel pairs 3.6/5.8 micron and 4.5/8.0 micron were centered on Trumpler 37. To reduce unnecessary data processing the authors analyzed only a portion of the original data that encompassed the Chandra-ACIS field with a coverage of ~19 x 19 arcmin<sup>2</sup> area in all four channels centered on Rim A of the IC 1396A globule. This covers 93% of the ACIS field omitting its north-western and south-western edges. An automated cross-correlation between the Chandra source positions and the optical-IR source positions was made using a search radius of 2 arcseconds within ~6 arcminutes of the ACIS field center, and a search radius of 3.5 arcseconds in the outer regions of the ACIS field where the X-ray source positions are more uncertain due to the deterioration of the Chandra telescope PSF. This was followed by a careful visual examination of each source in both bands to remove dubious sources and associations. This table was created by the HEASARC in April 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/426/2917">CDS Catalog J/MNRAS/426/2917</a> files table1.dat, table2.dat, and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ic348cxo2
- Title:
- IC 348 Chandra X-Ray Point Source Catalog 2
- Short Name:
- IC348CXO2
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- IC 348 is a nearby (~ 310 pc), young (~ 2 - 3 Myr) open cluster with > 300 members identified from optical and infrared observations. The authors studied the properties of the coronae of the young low-mass stars in IC 348, combining X-ray and optical/infrared data. The four existing Chandra observations of IC 348 were merged, thus providing a deeper and spatially more complete X-ray view than previous X-ray studies of the cluster. The authors compiled a comprehensive catalog of IC 348 members taking into account recent updates to the cluster census. Their data collection comprises fundamental stellar parameters, infrared excess indicating the presence of disks, H-alpha emission as a tracer of chromospheric emission or accretion, and mass accretion rates. The authors have detected 290 X-ray sources in four merged Chandra exposures, of which 185 are associated with known cluster members corresponding to a detection rate of ~ 60% for the cluster members of IC 348 identified in optical/infrared studies. According to the most recent spectral classification of IC 348 members, only four of the X-ray sources are brown dwarfs (spectral type M6 and later). The detection rate is highest for diskless Class III stars and increases with stellar mass. This may be explained with higher X-ray luminosities for higher mass and later evolutionary stage that is evident in the X-ray luminosity functions. In particular, the authors find that for the lowest examined masses (0.1 M<sub>sun</sub> - 0.25 M<sub>sun</sub>) there is a difference between the X-ray luminosity functions of accreting and non-accreting stars (classified on the basis of their H-alpha emission strength) as well as those of disk-bearing and diskless stars (classified on the basis of the slope of the spectral energy distribution). These differences disappear for higher masses. This is related to the finding that the L<sub>x</sub>/L<sub>bol</sub> ratio is non-constant across the mass/luminosity sequence of IC 348 with a decrease towards lower luminosity stars. Their analysis of an analogous stellar sample in the Orion Nebula Cluster suggests to the authors that the decline of L<sub>x</sub>/L<sub>bol</sub> for young stars at the low-mass end of the stellar sequence is likely universal. X-ray fluxes are presented for all (185) known optical/infrared IC348 members which were observed and detected by Chandra. The basic source parameters for all X-ray sources, i.e., including an additional 105 sources not associated with known IC 348 members, are given. The X-ray flux upper limits for 129 IC 348 members which were observed but not detected by Chandra (present in the as published version of Table 3 from the reference paper) are not included in this HEASARC representation of the data given in Tables 3 and 7 from the reference paper. Thus, this table contains 290 (185 + 105) rows, one for each X-ray source (IC 348 member or not) detected by Chandra in the direction of IC 348. This HEASARC table was created in February 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/537/A135">CDS Catalog J/A+A/537/A135</a> files table3.dat and table7.dat. It lists the X-ray counts and other properties for the 290 Chandra X-ray sources which were listed in table7.dat. It does not include the X-ray flux upper limits for 129 non-detected IC 348 members which were given in table3.dat, so only the X-ray fluxes and luminosities for the 185 X-ray detected IC 348 members given in table3.dat are included in this table. Notice that in the CDS version there were 2 duplicate entries in table3.dat. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ic10cxo
- Title:
- IC 10 Chandra X-ray Point Source Catalog
- Short Name:
- IC10CXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors monitored the Cassiopeia dwarf galaxy (IC 10) in a series of 10 Chandra ACIS-S observations to capture its variable and transient X-ray source population, which is expected to be dominated by High Mass X-ray Binaries (HMXBs). They present a sample of 21 X-ray sources that are variable between observations at the 3-sigma level, from a catalog of 110 unique point sources (the HEASARC notes that there are actually 111 sources in the CDS version of the catalog from which this HEASARC table originates). The authors find four transients (flux variability ratio greater than 10) and a further eight objects with ratios >5. The observations span the years 2003-2010 and reach a limiting luminosity of >10<sup>35</sup> erg/s, providing sensitivity to X-ray binaries in IC 10 as well as flare stars in the foreground Milky Way. The nature of the variable sources is investigated from light curves, X-ray spectra, energy quantiles, and optical counterparts. The purpose of this study is to discover the composition of the X-ray binary population in a young starburst environment. IC 10 provides a sharp contrast in stellar population age (<10 million years) when compared to the Magellanic Clouds (40-200 Myr) where most of the known HMXBs reside. The authors find 10 strong HMXB candidates, 2 probable background active galactic nuclei, 4 foreground flare-stars or active binaries, and 5 not yet classifiable sources. Complete classification of the sample requires optical spectroscopy for radial velocity analysis and deeper X-ray observations to obtain higher S/N spectra and search for pulsations. A catalog (contained in this HEASARC table) has been created and supporting data sets (the data used to create the light curves shown in Figures 3, 4 and 5 in the reference paper) are available at <a href="http://cdsarc.u-strasbg.fr/ftp/cats/J/ApJ/836/50/">http://cdsarc.u-strasbg.fr/ftp/cats/J/ApJ/836/50/</a>. A monitoring series of 7x15 ks Chandra/ACIS observations, spaced at roughly six-week intervals was obtained during 2009-2010. A pair of very deep ACIS-S3 observations (2x45ks) made in 2006 November provided a reference data set for improved source positions and spectral information. The original Wang+ (2005, MNRAS, 362, 1065) Chandra (ACIS-S3) observation of 30 ks made in 2003 was also included in this analysis. The complete listing of 10 Chandra observation identifiers (ObsIDs) comprising the data set is summarized in Table 1 of the reference paper, also shown here: <pre> MJD |Date |ObsID|Flag|Exp.|RA(J2000)Dec(J2000)|Roll|Num. Sources ks hh mm ss dd mm ss deg. 52710.7|2003 Mar 12 |03953|a |28.9|00 20 25 +59 16 55|339.27|31 54041.8|2006 Nov 2 |07082| |40.1|00 20 04 +59 16 45|223.70|48 54044.2|2006 Nov 5 |08458| |40.5|00 20 04 +59 16 45|223.70|41 55140.7|2009 Nov 5 |11080| |14.6|00 20 17 +59 17 56|226.53|19 55190.2|2009 Dec 25 |11081| | 8.1|00 20 19 +59 18 02|286.15|24 55238.5|2010 Feb 11 |11082| |14.7|00 20 23 +59 17 10|320.56|24 55290.6|2010 Apr 4 |11083| |14.7|00 20 34 +59 19 01| 10.32|25 55337.8|2010 May 21 |11084| |14.2|00 20 25 +59 20 16| 67.89|27 55397.5|2010 Jul 20 |11085| |14.5|00 20 11 +59 19 13|121.25|22 55444.6|2010 Sep 5 |11086| |14.7|00 20 15 +59 18 11|157.71|27 |2006 Nov 2-5 |57082|b |80.6|00 20 04 +59 16 45|223.70|63 </pre> Flag values as follows: <pre> a = ObsID 03953 used about half of the CCD area in subarray mode. b = Merged 2006 data set referred to as ObsID 57082 consists of the nearly contiguous ObsIDs 07082 and 08458, which had identical pointings. </pre> Roll is the spacecraft roll angle, and Num. Sources is the number of unique point sources detected in each observation after combining wavdetect lists from the soft (S: 0.3-1.5 keV), broad (B: 0.3-8 keV) and hard (H: 2.5-8 keV) energy bands. This table was created by the HEASARC in November 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/836/50">CDS Catalog J/ApJ/836/50</a> file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ic348cxo
- Title:
- IC 348 Chandra X-Ray Point Source Catalog
- Short Name:
- IC348CXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have obtained a deep (53 ks) X-ray image of the very young stellar cluster IC 348 with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. In this image with a sensitivity limit of ~ 1 x 10<sup>28</sup> ergs/s (more than 10 times deeper than their ROSAT images of IC 348), 215 X-ray sources were detected. While 115 of these sources can be identified with known cluster members, 58 X-ray sources are most likely new, still unidentified cluster members. About 80% of all known cluster members with masses between ~0.15 and 2 solar masses are visible as X-ray sources in the ACIS image. X-ray emission at levels of ~10<sup>28</sup> ergs/s was discovered from four of 13 known brown dwarfs and from three of 12 brown dwarf candidates in IC 348. X-ray emission was also detected from two deeply embedded objects, presumably class I protostars, south of the cluster center. Optical and infrared counterparts have been identified for most of the X-ray sources. Some 40 X-ray sources do not have optical or IR counterparts, and are most likely background (probably extragalactic) objects. This number is consistent with the expected number of extragalactic background X-ray sources based on the observed log N - log S statistics from the deep X-ray counts in the Chandra Deep Field South. This table was created by the HEASARC in January 2007 based on the merger of CDS table J/AJ/122/866/table1.dat (Table 1 from Preibisch and Zinnecker 2001) with the electronic AJ table version of Table 1 from Preibisch and Zinnecker 2002. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ic1396ncxo
- Title:
- IC 1396N Chandra X-Ray Point Source Catalog
- Short Name:
- IC1396NCXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The IC 1396N cometary globule (CG) within the large nearby HII region IC 1396 has been observed with the Advanced CCD Imaging Spectrometer (ACIS) detector on board the Chandra X-Ray Observatory on 2004 October 16.93 to 17.30. 117 X-ray sources are detected, of which ~ 50-60 are likely members of the young open cluster Trumpler 37 dispersed throughout the HII region, and 25 are associated with young stars formed within the globule. Infrared photometry (2MASS and Spitzer) shows that the X-ray population is very young: 3 older Class III stars, 16 classical T Tauri stars, and 6 protostars including a Class 0/I system. The authors infer a total T Tauri population of ~ 30 stars in the globule, including the undetected population, with a star formation efficiency of 1%-4%. An elongated source spatial distribution with an age gradient oriented toward the exciting star is discovered in the X-ray population of IC 1396N, supporting similar findings in other cometary globules. The geometric and age distribution is consistent with the radiation-driven implosion (RDI) model for triggered star formation in CGs by H II region shocks. The authors include only results arising from the imaging array (ACIS-I) of four abutted 1024 x 1024 pixel front-side illuminated CCDs covering about 17' x 17' on the sky. The aim point of the array was R.A. = 21h40m42.4s, Dec. = +58d1609.7" (J2000.0) or (l,b) = (100.0, + 4.2), and the satellite roll angle (i.e., orientation of the CCD array relative to the north-south direction) was 245.9 degrees. The total net exposure time of the observation is 30 ks with no background flaring due to solar activity or data losses. This table was created by the HEASARC in February 2009 based on the electronic version of Tables 1 and 2 from the paper which were obtained from the CDS (their catalog J/ApJ/654/316 files table1.dat and table2.dat). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ir20126cxo
- Title:
- IRAS 20126+4104 Chandra X-Ray Point Source Catalog
- Short Name:
- IR20126CXO
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6-cm continuum observations of the IRAS 20126+4104 massive star-forming region. The authors detect 150 X-ray sources within the 17' x 17' ACIS-I field, and a total of 13 radio sources within the 9.2' primary JVLA beam at 4.9 GHz. Among these observations are the first 6-cm detections of the central sources reported by Hofner et al. (2007, A&A, 465, 197), namely, I20N1, I20S, and I20var. A new variable radio source is also reported in Section 3.2 of the reference paper, [MHA2015] VLA G78.1907+3.364. Searching the 2MASS archive, the authors identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6-cm counterparts. Based on an NIR color-color analysis and on the Besancon simulation of Galactic stellar populations, the authors estimate that approximately 80 X-ray sources are associated with this massive star-forming region. They detect an increasing surface density of X-ray sources toward the massive protostar IRAS 20126+4104 and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from this protostar. The authors observed the IRAS 20126+4104 region with the Chandra ACIS-I instrument on 2003 March 17 for a total exposure time of 39.35 ks. C-band (6 cm) continuum observations of the massive star-forming region IRAS 20126+4104 were conducted with the VLA operated by NRAO on 2011 August 7. These X-ray and radio data are augmented by NIR and optical archival data. For the Mid-IR wavelength regions, the authors searched the Spitzer Enhanced Imaging Products Point Source catalog. This table was created by the HEASARC in March 2016 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/219/41">CDS catalog J/ApJS/219/41</a> files table1.dat and table5.dat. This is a service provided by NASA HEASARC .
