- ID:
- ivo://nasa.heasarc/ecdfsoid
- Title:
- Extended Chandra Deep Field-South Survey Optical Identifications Catalog
- Short Name:
- ECDFSOID
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the first results of the authors' optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South (ECDFS). A total of 339 sources (listed herein) were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. The authors have measured redshifts for 186 X-ray sources, including archival data and a literature search. They find that the active galactic nucleus (AGN) host galaxies have on average redder rest-frame optical colors than nonactive galaxies, and that they live mostly in the "green valley." The dependence of the fraction of AGNs that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN spatial density is compared with the expectations from existing luminosity functions. These AGNs show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGNs, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity. This table was created by the HEASARC in April 2009 based on the electronic version of Table 2 from the Treister et al. (2009) paper obtained from the ApJ web site, except for the source positions which were taken from Virani et al. (2006). The full table from the latter paper is also available in Browse (the ECDFSCXO table). This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/ecdfscxo
- Title:
- Extended Chandra Deep Field-South X-Ray Point Source Catalog
- Short Name:
- ECDFSCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Extended Chandra Deep Field-South (ECDFS) survey consists of four Chandra X-Ray Observatory (CXO) ACIS-I pointings and covers ~1100 arcmin<sup>2</sup> (~0.3 deg<sup>2</sup>) centered on the original CDF-S field to a depth of approximately 228 ks. This is the largest Chandra survey ever conducted at such depth, and only one XMM-Newton survey reaches a lower flux limit in the hard 2.0-8.0 keV band. The authors detect 651 unique sources: 587 using a conservative source-detection threshold (identified by source_type = 'P' for primary source) and 64 (identified by source_type = 'S' for secondary source) using a lower source-detection threshold. These are combined in this HEASARC representation but were presented as two separate catalogs (Table 4 contained the primary sources, and Table 5 the secondary sources) in the original reference paper. Of the 651 total sources, 561 are detected in the full 0.5-8.0 keV band, 529 in the soft 0.5-2.0 keV band, and 335 in the hard 2.0-8.0 keV band. For point sources near the aim point, the limiting fluxes are approximately 1.7 x 10<sup>-16</sup> and 3.9 x 10<sup>-16</sup> ergs/cm<sup>2</sup>/s in the 0.5-2.0 and 2.0-8.0 keV bands, respectively. In their paper, the authors present the differential and cumulative flux distributions, which are in good agreement with the number counts from previous deep X-ray surveys and with the predictions from an active galactic nucleus (AGN) population synthesis model that can explain the X-ray background. In general, fainter sources have harder X-ray spectra, consistent with the hypothesis that these sources are mainly obscured AGNs. All nine observations of the ECDFS survey field were conducted with the Advanced CCD Imaging Spectrometer (ACIS) on board Chandra as part of the approved guest observer program in Cycle 5. Notice that Lehmer et al. (2005, ApJS, 161, 21) conducted a somewhat different analysis on these same data and obtained similar, but not identical results, e.g., Lehmer et al. found 809 total X-ray sources compared to 651 in the present table. This table was created by the HEASARC in April 2009 based on the electronic versions of Tables 4 and 5 from the paper which were obtained from the CDS (their catalog J/AJ/131/2373 files table4.dat and table5.dat). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/vlulxcat
- Title:
- Extremely Luminous X-Ray Source Candidates Catalog
- Short Name:
- VLULXCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Using Chandra archive data, the authors conducted a thorough survey of luminous X-ray sources. They directly analyzed about 9400 Chandra ACIS observations and cross-correlated the detected X-ray sources with 77,000 galaxies within a distance of 250 Mpc. The final catalog includes 119 unique luminous X-ray source candidates with L<sub>X</sub> > 3 x 10<sup>40</sup> erg/s from 93 galaxies or 41 HLX candidates with L<sub>X</sub> > 1 x 10<sup>41</sup> erg/s from 35 galaxies. The authors derive a moderate contamination rate due to foreground or background sources. In the reference paper, they also cross-correlate the catalog with FIRST, perform variability and periodicity tests, and analyze one HLX candidate in particular. This catalog could be a starting point to perform follow-up observations. In order to know whether an X-ray source falls within a particular galaxy, for each galaxy, the authors collected its center's RA, Dec, distance, and D<sub>25</sub> isophotal info, which includes major axis length, minor axis length, and the position angle of the major axis from the PGC2003 Catalog (Paturel et al. 2003, A&A, 412, 45), which includes the full RC3 catalog and has all of the necessary parameters except for distance. The authors restricted the minimum major axis length to be 10 arcseconds, and collected their distances from NED as much as possible. Their final sample includes 77,000 galaxies within 250 Mpc. The authors used all of the Chandra ACIS data in TE mode that were released before 2014, which includes 9400 ObsIDs. A roughly linear relation between the flux and count rate derived by PIMMS 4.6b was established assuming a power-law spectral shape and galactic foreground extinction (Kalberla et al. 2005, A&A, 440, 775). Any source with a PIMMS luminosity larger than 5 x 10<sup>39</sup> erg s<sup>-1</sup> would be recalculated by the CIAO script model flux assuming a power-law index of 1.7 in the 0.3 - 8.0 keV energy band. After the recalculation, 1,809 X-ray sources with L<sub>x</sub> > 3 x 10<sup>40</sup> erg s<sup>-1</sup> falling within 640 D<sub>25</sub> contours covered by 905 ObsIDs were picked out. A large fraction of the 1,809 sources are galactic nuclei and some of them are repeated. Only off-nuclear sources are considered in this paper. In addition, the centers of the galaxies given by PGC2003 are not necessarily precise and the specific environments of the 1,809 sources are different. Therefore, the authors visually checked the Chandra and DSS images simultaneously, since two-band inspection can help to exclude the nuclear sources, bright knots, and extended sources. X-ray sources with clear DSS features would be dropped because, for a source with a visual magnitude <20 and a distance >30 Mpc, its absolute magnitude would be brighter than -12.4, which is beyond the limit of the brightest star clusters. This table was created by the HEASARC in February 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/222/12">CDS Catalog J/ApJS/222/12</a> file table1.dat, the list of very luminous X-ray source candidates found within the D<sub>25</sub> ellipses of Chandra ACIS-observed PGC2003 galaxies lying within 250 Mpc. 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/fornaxacxo
- Title:
- Fornax A (NGC 1316) Chandra X-Ray Source Catalog
- Short Name:
- FORNAXACXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from a Chandra ACIS sub-arcsecond resolution X-ray observation of the archetypal merger radio galaxy NGC 1316 (Fornax A). The authors detect 81 point sources within the 25th magnitude isophotal ellipse D<sub>25</sub> of NGC 1316 (L<sub>X</sub> in the range of 2 x 10<sup>37</sup> to 8 x 10<sup>39</sup> ergs s<sup>-1</sup>), with hard (kT ~ 5 keV) X-ray spectra, typical of X-ray binaries, and a spatial radial distribution consistent with that of the optical (i.e., stellar) surface brightness. In the reference paper, they derive the X-ray luminosity function (XLF) of these sources, correcting for the incompleteness at the faint end caused by the presence of the diffuse emission from the hot ISM in the central regions of NGC 1316 and by the widening of the Chandra point-spread functions at increasing distance from the aim point. With these corrections, the XLF is well reproduced by a single unbroken power law with a slope of -1.3 down to their threshold luminosity of ~ 3 x 10<sup>37</sup> ergs s<sup>-1</sup>. NGC 1316 was observed for 30 ks on 2001 April 17 (ObsID 2022), with the Chandra Advanced CCD Imaging Spectrometer (ACIS). The authors used the back-illuminated (BI) CCD S3 (CCD ID 7) because of its sensitivity at low energies. To include NGC 1317 (6.3 arcminutes away from NGC 1316) in the same S3 chip, a small offset was applied to the SIM (Science Instrument Module) position. NGC 1316 was kept close to on-axis to achieve the best spatial resolution. To detect X-ray sources, the authors used WAVDETECT, a wavelet detection algorithm available in CIAO. They set the WAVDETECT significance threshold parameter to be 10<sup>-6</sup>, which corresponds to 1 possibly spurious source, and the scale parameter to cover seven steps between 1 and 64 pixels. This made them sensitive to sources ranging from point-like to 32 arcseconds in size, and in particular accommodates the variation of the point-spread function (PSF) as a function of the off-axis angle of the sources. To extract source properties (such as count rates, spectra, etc.), the authors used the 95% encircled energy (at 1.5 keV) radius centered at the WAVDETECT centroid, with a minimum of 3 arcseconds to accommodate the radial variation of he PSF. Background counts were determined locally for each source from an annulus from 2 to 5 times the source radius, after excluding nearby sources. Extended sources were found at the locations of NGC 1316 and NGC 1317. In addition, the Chandra observations reveal 94 sources (the HEASARC notes that 95 are contained in this table), 83 of them in CCD S3. Of these, 81 sources (77 in S3 and 4 in S2) are within the D<sub>25</sub> ellipse. The source density increases toward the center of NGC 1316, indicating that most of them are related to NGC 1316. Three sources are found within the D<sub>25</sub> ellipse of NGC 1317, with the brightest, extended one at the center of NGC 1317. The list of detected sources also includes sources found on CCDs other than S3 (CCD number 7). After correcting for effective exposure and vignetting, the X-ray flux in the 0.3 - 8.0 keV band is calculated with an energy conversion factor (ECF) assuming a power-law source spectrum with a slope of 1.7 and N<sub>H</sub> = 3 x 10<sup>20</sup> cm<sup>-2</sup>; ECF = 6.037 x 10<sup>-12</sup> erg cm<sup>-2</sup> s<sup>-1</sup> ergs per 1 count s<sup>-1</sup> for the back-illuminated (BI) chips and 9.767 x 10<sup>-12</sup> ergs per 1 count s<sup>-1</sup> for the front-illuminated (FI) CCD chips. With the adopted distance of 18.6 Mpc, the X-ray luminosities of the point sources range from ~ 2 x 10<sup>37</sup> to ~ 8 x 10<sup>39</sup> erg s<sup>-1</sup>. This table was created by the HEASARC in July 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/586/826">CDS Catalog J/ApJ/586/826</a> file table1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/galcencxo
- Title:
- Galactic Center Chandra X-Ray Point Source Catalog
- Short Name:
- GALCENCXO
- Date:
- 07 Mar 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 .
- ID:
- ivo://nasa.heasarc/galccxonid
- Title:
- Galactic Center Chandra X-Ray Source Near-IR Counterparts
- Short Name:
- GALCCXONID
- Date:
- 07 Mar 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:
- 07 Mar 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:
- 07 Mar 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:
- 07 Mar 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:
- 07 Mar 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 .
