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601. NGC 3293 Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc3293cxo
Title:: NGC 3293 Chandra X-Ray Point Source Catalog
Short Name:: NGC3293CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: NGC 3293 is a young stellar cluster at the northwestern periphery of the Carina Nebula Complex that has remained poorly explored until now. The authors wanted to characterize the stellar population of NGC 3293 in order to evaluate key parameters of the cluster population like the age and the mass function, and to test claims of an abnormal initial mass function (IMF) and a deficit of <= 2.5*Msun stars. Thus, they performed a deep (71 ksec) X-ray observation of NGC 3293 with Chandra in which they detected 1026 individual X-ray point sources. These X-ray data directly probe the low-mass (M <= 2*Msun) stellar population by means of the strong X-ray emission of young low-mass stars. The authors have identified counterparts for 74% of the X-ray sources in their deep near-infrared images. These data clearly show that NGC 3293 hosts a large population of ~ 1*Msun stars, refuting claims of a lack of M <= 2.5*Msun stars. The analysis of the color-magnitude diagram suggests an age of ~8-10 Myr for the low-mass population of the cluster. There are at least 511 X-ray detected stars with color-magnitude positions that are consistent with young stellar members within 7 arcminutes from the cluster center. The number ratio of X-ray detected stars in the 1-2 solar mass range versus the M >= 5*Msun stars (known from optical spectroscopy) is well consistent with the expectation from a normal field initial mass function. Most of the early B-type stars and ~20% of the later B-type stars are detected as X-ray sources. These data shows that NGC 3293 is one of the most populous stellar clusters in the entire Carina Nebula Complex (only excelled by Tr 14, and very similar to Tr 16 and Tr 15). The cluster has probably harbored several O-type stars, the supernova explosions of which may have had an important impact on the early evolution of the Carina Nebula Complex. The authors used the Chandra X-ray Observatory to perform a deep pointing of the cluster NGC 3293 with the Imaging Array of the Chandra Advanced CCD Imaging Spectrometer (ACIS-I). The 71-ksec observation was performed as an open time project with ObsID 16648 (PI: T. Preibisch) during Chandra Observing Cycle 15 in October 2015 (start date: 2015-10-07 T10:14:23, end date: 2015-10-08 T06:43:28). The imaging array ACIS-I provides a field of view of 17' x 17' on the sky (which corresponds to a scale of 11.3 x 11.3pc at the cluster distance of 2.3 kpc), and has a pixel size of 0.492". The aimpoint of the observation was RA(J2000) = 10h 35m 50.07s, Dec(J2000) = -58o 14' 00", which is close to the optical center of the cluster (see Fig. 1 in the reference paper). The pointing roll angle (i.e., the orientation of the detector with respect to the celestial North direction) was 140.19o. In addition to ACIS-I, one CCD detector (CCD 7 = S3) of the spectroscopic array ACIS-S was also operational during this pointing. It covers an 8.3' x 8.3' area on the sky southwest of the cluster center. While the ACIS-I chips are front-illuminated (FI), the S3 chip is back-illuminated (BI), and thus its response extends to energies below that accessible by the FI chips. This causes a substantially higher level of background in the S3 chip. Furthermore, the PSF is seriously degraded at the rather large off-axis angles of the S3 chip. These two effects led to a considerably higher detection limit for point sources in the area covered by the S3 chip compared to the region covered by the ACIS-I array. Nevertheless, the S3 data were included in the data analysis and source detection, and contributed four point sources to the total source list. At the distance of 2.3 kpc, the expected ACIS point source sensitivity limit for a three-count detection on-axis in a 71-ks observation corresponds to a minimum X-ray luminosity of Lx ~ 1029.7 erg s-1 in the 0.5-8.0 keV energy band, assuming an extinction of AV ~ 1 mag (NH ~ 2 x 1021 cm-2) typical for the stars in the central region of NGC 3293, and a thermal plasma with kT = 1 keV (which is a typical value for young stars). Using the empirical relation between X-ray luminosity and stellar mass and the temporal evolution of X-ray luminosity from the sample of young stars in the Orion Nebula Cluster, which was very well studied in the Chandra Orion Ultradeep Project (Preibisch et al. 2005, ApJS, 160, 401; Preibisch & Feigelson 2005, ApJS, 160, 390), the authors expected to detect ~90% of the ~ 1*Msun stars in the central region of the young cluster NGC 3293. The X-ray properties of the 97 B-type stars in the ACIS-I field towards the cluster (24 of which are detected as X-ray sources) are not included in this HEASARC table, but are listed in Table 3 of the reference paper, which is also reproduced below: <pre> ESL No.* Star Name X-ray Spectral Type X-ray Luminosity (Lx) log (Lx/Lbol) Src No. erg/s 49 B2.5 V < 4.33e+30 < -5.88 33 HDE 303073 B8 III < 7.15e+30 < -6.31 65 ALS 20075 B5 III-V < 2.12e+30 < -5.88 77 B6-7 V < 1.42e+30 < -5.91 96 ALS 20084 B6-7 III < 9.09e+29 < -5.96 87 47 B5 V 4.62e+30 -5.11 38 B2.5 V < 7.16e+29 < -6.94 68 78 B9 III 4.79e+30 72 B8 IIp < 6.87e+29 69 B5 V < 3.89e+29 < -6.47 22 HDE 303075 B0.5-1.5n < 6.22e+29 < -7.77 109 B5 V < 5.05e+29 < -6.06 93 B6-7 V < 5.16e+29 < -6.17 116 B6-7 V < 4.74e+29 < -5.88 73 B6-7 V < 3.87e+29 < -6.38 10 CPD-57 3500 395 B1 III 7.35e+29 -7.89 121 ALS 20096 B8: III < 4.84e+29 50 B3 Vn < 5.01e+29 < -6.71 2 HD 91943 418 B0.7 Ib 4.11e+30 -8.15 41 V438 Car B2.5 V < 3.94e+29 < -7.21 48 CPD-57 3505 461 B2.5 V 1.39e+30 -6.67 3 CPD-57 3506A 490 B1 III 5.37e+30 -7.63 125 B8 III-V < 8.62e+29 < -5.48 19 V405 Car 523 B1 V 6.77e+29 -7.88 34 CPD-57 3509 535 B2 IIIh 6.71e+29 -7.54 1 HD 91969 542 B0 Iab 2.78e+31 -7.52 106 565 B6-7 V 1.20e+30 -5.54 53 CPD-57 3512 B3 V < 3.61e+29 < -6.70 98 598 B8 III-V 1.31e+30 -5.65 30 CPD-57 3514 601 B2 V 1.99e+30 -6.64 123 604 B8 III 3.79e+30 -4.98 8 HD 91983 626 B1 III 1.36e+30 -7.78 32 CPD-57 3518 B0.5-B1.5 Vn < 1.20e+30 < -7.14 61 B5 V < 3.87e+29 < -6.56 5 CPD-57 3521 679 B1 III 3.45e+30 -7.61 28 CPD-57 3520 B2 V < 4.16e+29 < -7.46 113 B6-7 V < 4.09e+29 < -6.01 11 CPD-57 3526 703 B1: 2.29e+30 6 CPD-57 3526B 710 B1 III 2.29e+30 -7.73 84 B5 V < 3.99e+29 < -6.33 31 CPD-57 3528 B2 V < 1.50e+30 < -6.66 29 CPD-57 3531 B0.5-B1.5 Vn < 5.99e+29 < -7.56 59 B5 III-Vn < 8.23e+29 < -6.61 80 B5 V < 1.31e+30 < -5.98 13 HD 92024 831 B1 III 6.59e+29 -7.82 108 850 B6-7 V 3.65e+30 -5.09 95 884 B6-7 V 1.49e+30 -5.66 67 B3 V < 1.20e+30 < -6.42 97 B6-7 III < 6.34e+29 < -6.01 94 927 B5 V 4.42e+30 -5.35 85 B5 V < 1.47e+30 < -5.80 4 CPD-57 3523 697 B1 III 3.40e+30 -7.57 7 HD 92044 908 B1 III 2.20e+30 -7.94 14 CPD-57 3524A 704 B0.5 IIIn 5.46e+30 -7.27 </pre> * The ESL number is the source number of the star as given in Evans et al. (2005, A&A, 437, 467). This table was created by the HEASARC in September 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/605/A85">CDS Catalog J/A+A/605/A85</a> files table1.dat and table2.dat. This is a service provided by NASA HEASARC .

602. NGC 4636 Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc4636cxo
Title:: NGC 4636 Chandra X-Ray Point Source Catalog
Short Name:: NGC4636CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This catalog lists the X-ray point-source population in the nearby Virgo elliptical galaxy NGC 4636 from three Chandra X-ray observations. These observations, totaling ~193 ks after time filtering, were taken with the Advanced CCD Imaging Camera (ACIS) over a three-year period. Using a wavelet decomposition detection algorithm, the authors detected 318 individual point sources. For their analysis, they used a subset of 277 detections with >= net 10 counts (a limiting luminosity of approximately 1.2 x 1037 erg s-1 in the 0.5-2 keV band, outside the central 1.5 arcminutes bright galaxy core). This table contains this subset of 277 X-ray sources. The authors discuss the radial distribution of the point sources. Between 1.5 and 6 arcminutes from the center, 25% of the sources are likely to be background sources (active galactic nuclei (AGNs)) and 75% to be low-mass X-ray binaries (LMXBs) within the galaxy, while at radial distances greater than 6 arcminutes, background sources (AGN) will dominate the point sources. The authors explore short and long-term variability (over timescales of 1 day to three years) for X-ray point sources in this elliptical galaxy. 54 sources (24%) in the common ACIS fields of view show significant variability between observations. Of these, 37 are detected with at least 10 net counts in only one observation and thus may be "transient." In addition, ~10% of the sources in each observation show significant short-term variability. The cumulative luminosity function (LF) for the point sources in NGC 4636 can be represented as a power law of slope Alpha = 1.14 +/- 0.03. The authors do not detect, but estimate an upper limit of ~4.5 x 1037 erg s-1 to the current X-ray luminosity of, the historical supernova SN1939A. They find 77 matches between X-ray point sources and globular cluster (GC) candidates found in deep optical images of NGC 4636. In the annulus from 1.5 to 6 arcminutes of the galaxy center, 48 of the 129 X-ray point sources (37%) with >=10 net counts are matched with GC candidates. Since they expect 25% of these sources to be background AGN, the percentage matched with GCs could be as high as 50%. Of these matched sources, the authors find that ~70% are associated with the redder GC candidates, those that are thought to have near-solar metal abundance. The fraction of GC candidates with an X-ray point source match decreases with decreasing GC luminosity. The authors do not find a correlation between the X-ray luminosities of the matched point sources and the luminosity or color of the host GC candidates. The LFs of the X-ray point sources matched with GCs and those that are unmatched have similar slopes over 1.8 x 1037 erg s-1 <= Lx <= 1 x 1038 erg s-1. This table was created by the HEASARC in July 2009 based on electronic versions of Tables 2 and 3 from the paper obtained from the ApJ web site, but excluding the 7 entries in Table 3 which corresponded to weaker X-ray sources which were not listed in Table 2. 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 .

603. NGC 6231 Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc6231cxo
Title:: NGC 6231 Chandra X-Ray Point Source Catalog
Short Name:: NGC6231CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: NGC 6231 is a massive young star cluster, near the center of the Sco OB1 association. While its OB members are well studied, its low-mass population has received little attention. In the reference paper, the authors present high-spatial resolution Chandra ACIS-I X-ray data, wherein they detect 1,613 point X-ray sources. Their main aim was to clarify the global properties of NGC 6231 down to low masses through a detailed membership assessment, and to study the cluster stars' spatial distribution, the origin of their X-ray emission, the cluster age and formation history, and its initial mass function. The authors use X-ray data, complemented by optical and IR data, to establish cluster membership. The spatial distribution of different stellar subgroups also provides highly significant constraints on cluster membership, as does the distribution of X-ray hardness. In their study, the authors perform spectral modeling of group-stacked X-ray source spectra. The X-ray properties of the sources detected in the Chandra observations of NGC 6231, and their cross-identifications in the catalogs of Sung, Sana, and Bessell (2013 AJ, 145, 37; hereafter SSB); VPHAS+ (Drew et al., 2014, MNRAS, 440, 2036); and 2MASS (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/II/246">CDS Cat. II/246</a>), and information about membership, H-alpha or IR excess, mass and luminosity are also provided. SSB derive a distance modulus for NGC 6231 of 11.0 (1,585 pc), a reddening E(B - V) = 0.47, and a nearly normal reddening law with R = 3.2. The present authors adopt these values for this work. NGC 6231 was observed twice in X-rays with the ACIS-I detector on-board the Chandra X-ray Observatory on 2005, July 3 to 4 (ObsId 5372) and 16 to 17 (ObsID 6291), respectively. The two pointings share the same center (aimpoint) but were performed with a different roll angle. Effective exposure times for the observations were 76.19 and 44.39 ks, respectively, making the total exposure time 120.58 ks. The data were filtered to retain the energy band 0.3 - 8.0 keV, and the full-field lightcurves were inspected to search for high-background periods, but none were found. Exposure maps were computed using standard CIAO software tasks. To these prepared datasets, the authors applied the source detection software PWDetect, a wavelet-based detection algorithm developed at INAF-Osservatorio Astronomico di Palermo. The PWDetect version used here is a modified one, able to detect sources in combined datasets, thus taking full advantage of the deep total exposure. The detection threshold was chosen such as to yield ten spurious detections in the field of view (FOV), for the given background counts. This is a more relaxed constraint than the more usual limit of one spurious detection per field, but is justified when the lowered threshold allows the detection of more than one hundred additional faint sources, as it was the case here or in the COUP Program's Orion data. This HEASARC table contains the list of 1,613 detected X-ray point sources and information about their optical and IR counterparts, where known. It does not contain the 275 additional candidate cluster members (where their candidacy was based on their having H-alpha or IR excesses) which lack X-ray counterparts and that were also listed in Table B.2 of the reference paper. This table was created by the HEASARC in December 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/596/A82">CDS Catalog J/A+A/596/A82</a> file tableb.dat, which is the merger of tables B.1 (the list of 1,613 X-ray sources) and B.2 (the list of 1,888 optical and near-IR identifications of X-ray sources and of IR- and H-alpha-excess stars) from the reference paper, but excluding the 275 stars listed in the latter whose candidacy was based on their having H-alpha or IR excesses and which lack X-ray counterparts. # This is a service provided by NASA HEASARC .

604. NGC 1399 Chandra X-Ray Source Catalog

ID:: ivo://nasa.heasarc/ngc1399cxo
Title:: NGC 1399 Chandra X-Ray Source Catalog
Short Name:: NGC1399CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains results from a wide-field study of the globular cluster (GC)/low-mass X-ray binary (LMXB) connection in the giant elliptical NGC 1399. The large field of view of the Advanced Camera for Surveys/WFC, combined with the high resolution of the Hubble Space Telescope and Chandra, allow the authors to constrain the LMXB formation scenarios in elliptical galaxies. They confirm that NGC 1399 has the highest LMXB fraction in GCs of all nearby elliptical galaxies studied so far, even though the exact value depends on galactocentric distance due to the interplay of a differential GC versus galaxy light distribution and the GC color dependence. In fact, LMXBs are preferentially hosted by bright, red GCs out to > 5 Reff of the galaxy light. The finding that GCs hosting LMXBs follow the radial distribution of their parent GC population argues against the hypothesis that the external dynamical influence of the galaxy affects the LMXB formation in GCs. On the other hand, field-LMXBs closely match the host galaxy light, thus indicating that they are originally formed in situ and not inside GCs. The authors measure GC structural parameters, finding that the LMXB formation likelihood is influenced independently by mass, metallicity, and GC structural parameters. In particular, the GC central density plays a major role in predicting which GCs host accreting binaries. Finally, this analysis shows that LMXBs in GCs are marginally brighter than those in the field, and in particular the only color-confirmed GC with LX > 1039 erg/s shows no variability, which may indicate a superposition of multiple LMXBs in these systems. The optical data were taken with the ACS on board the HST (GO-10129), in the F606W filter. A detailed description of the HST data and source catalogs are given in Puzia T.H. et al. 2011, in preparation. The X-ray data were retrieved from the Chandra public archive (CXC). The authors selected observations 319 (ACIS-S; 2000 Jan 18) and 1472 (ACIS-I; 2003 May 26). This table contains the list of 230 X-ray sources detected in the overlap region common to Chandra ACIS-I, Chandra ACIS-S and HST ACS observation (see Fig 1 of the reference paper). Details of the X-ray source detection methodology are given in Section 2.2 of the reference paper. This table was created by the HEASARC in January 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/736/90">CDS Catalog J/ApJ/736/90</a> file table3.dat. This is a service provided by NASA HEASARC .

605. NGC 2516 Cluster XMM-Newton X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc2516xmm
Title:: NGC 2516 Cluster XMM-Newton X-Ray Point Source Catalog
Short Name:: NGC2516XMM
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains the results from a deep X-ray survey of the young (~ 140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite. By combining the data from six observations, a high sensitivity, greater than a factor of 5 with respect to recent Chandra observations, has been achieved. Kaplan-Meier estimators of the cumulative X-ray luminosity distribution, statistically corrected for non-member contaminants, were built by the authors and compared to those of the nearly coeval Pleiades cluster. 431 X-ray sources were detected, and 234 of them have as optical counterparts cluster stars spanning the entire NGC 2516 main sequence. On the basis of X-ray emission and optical photometry, 20 new candidate members of the cluster have been identified; at the same time there are 49 X-ray sources without known optical or infrared counterpart. The X-ray luminosities of cluster stars span the range log Lx (erg s-1) = 28.4 - 30.8. The representative coronal temperatures span the 0.3 - 0.6 keV (3.5 - 8 MK) range for the cool component and 1.0 - 2.0 keV (12 - 23 MK) for the hot one; similar values were found in other young open clusters like the Pleiades, IC 2391, and Blanco 1. While no significant differences were found in their X-ray spectra, NGC 2516 solar-type stars are definitely less luminous in X-rays than their nearly coeval Pleiades counterparts. The comparison with a previous ROSAT survey reveals the lack of variability amplitudes larger than a factor of 2 in solar-type cluster stars in a ~ 11 yr time scale, and thus activity cycles like in the Sun are probably absent or have a different period and amplitude in young stars. NGC 2516 has been observed several times with XMM-Newton during the first two years of satellite operations for calibration purposes. The observations used in this analysis span a period of 19 months with exposure times between 10 and 20 ks. All of these observations have been performed with the thick filter. In the combined EPIC datasets the authors detected 431 X-ray sources with a significance level greater than 5.0 sigma, which should lead statistically to at most one spurious source in the field of view. This table was created by the HEASARC in May 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/450/993">CDS catalog J/A+A/450/993</a> files tablea1.dat and tableb1.dat. This is a service provided by NASA HEASARC .

606. NGC2000.0: Complete New General Catalog and Index Catalog

ID:: ivo://nasa.heasarc/ngc2000
Title:: NGC2000.0: Complete New General Catalog and Index Catalog
Short Name:: NGC
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: NGC 2000.0 is a modern compilation of the New General Catalogue of Nebulae and Clusters of Stars (NGC), the Index Catalogue (IC), and the Second Index Catalogue compiled by J. L. E. Dreyer (1888, 1895, 1908). The new compilation of these classical catalogs is intended to meet the needs of present-day observers by reporting positions at equinox 2000.0 and by incorporating the corrections reported by Dreyer himself and by a host of other astronomers who have worked with the data and compiled lists of errata. The object types given are those known to modern astronomy. This catalog is copyrighted by Sky Publishing Corporation, which has kindly deposited the machine-readble version in the data centers for permanent archiving and dissemination to astronomers for scientific research purposes only. The data should not be used for commercial purposes without the explicit permission of Sky Publishing Corporation. Information on how to contact Sky Publishing is available at <a href="http://www.shopatsky.com/contacts">http://www.shopatsky.com/contacts</a>. This HEASARC table was last updated in September 2022, based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/118">CDS catalog VII/118</a> file ngc2000.dat, in order to correct some truncated description fields. The previous update was in June 2005. This is a service provided by NASA HEASARC .

607. NGC 1512/NGC 1510 XMM-Newton X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc1512xmm
Title:: NGC 1512/NGC 1510 XMM-Newton X-Ray Point Source Catalog
Short Name:: NGC1512XMM
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The galaxy NGC 1512 is interacting with the smaller galaxy NGC 1510 and shows a peculiar morphology, characterized by two extended arms immersed in an HI disc whose size is about four times larger than the optical diameter of NGC 1512. The authors have performed the first deep X-ray observation of the galaxies NGC 1512 and NGC 1510 with XMM-Newton to gain information on the population of X-ray sources and diffuse emission in this system of interacting galaxies. They have identified and classified the sources detected in the XMM-Newton field of view by means of spectral analysis, hardness-ratios calculated with a Bayesian method, X-ray variability, and cross-correlations with catalogs in optical, infrared, and radio wavelengths. They also made use of archival Swift (X-ray) and Australia Telescope Compact Array (radio) data to better constrain the nature of the sources detected with XMM-Newton. They detected 106 sources in the energy range of 0.2 - 12 keV, out of which 15 are located within the D25 regions of NGC 1512 and NGC 1510 and at least six sources coincide with the extended arms. They identified and classified six background objects and six foreground stars. In the reference paper, they discuss the nature of a source within the D25 ellipse of NGC 1512, whose properties indicate a quasi-stellar object or an intermediate ultra-luminous X-ray source. Taking into account the contribution of low-mass X-ray binaries and active galactic nuclei, the number of high-mass X-ray binaries detected within the D25 region of NGC 1512 is consistent with the star formation rate obtained in previous works based on radio, infrared optical, and UV wavelengths. The authors detected diffuse X-ray emission from the interior region of NGC 1512 with a plasma temperature of kT = 0.68(0.31-0.87) keV and a 0.3 - 10 keV X-ray luminosity of 1.3E+38erg/s, after correcting for unresolved discrete sources. The galaxy pair NGC 1512/1510 was observed with XMM-Newton (ObsID: 0693160101) between 2012 June 16 (20:31 UTC) and 2012 June 17 (16:24 UTC) in a single, 63-ks exposure observation. The data analysis was performed through the XMM-Newton Science Analysis System (SAS) software (version 12.0.1). The observation was largely contaminated by high background due to proton flares. After rejecting time intervals affected by high background, the net good exposure time was reduced to 26.0 ks for PN, 39.8 ks for the MOS1 and 34.8 ks for the MOS2. For each instrument, the data were divided into five energy bands: <pre> B1 : 0.2 - 0.5 keV B2 : 0.5 - 1.0 keV B3 : 1.0 - 2.0 keV B4 : 2.0 - 4.5 keV B5 : 4.5 - 12.0 keV </pre> For the PN, data were filtered to include only single events (PATTERN = 0) in the energy band B__1, and single and double events (PATTERN <= 4) for the other energy bands. The authors excluded the energy range 7.2 - 9.2 keV to reduce the background produced by strong fluorescence lines in the outer detector area. For the MOS, single to quadruple events (PATTERN <= 12) were selected. The source detection procedure is described in Section 2.1 of the reference paper. In the final step, the authors adopted a minimum likelihood of L = 6. They removed false detections (artifacts on the detectors or diffuse emission structures) by visual inspection. They detected 106 total point sources in the NGC 1512/1510 field of view. This table was created by the HEASARC in July 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/566/A115">CDS Catalog J/A+A/566/A115</a> files tableb1.dat and tableb2.dat. This is a service provided by NASA HEASARC .

608. NGC 6357/Pismis 24 Chandra Point Source Optical/IR Identifications Catalog

ID:: ivo://nasa.heasarc/ngc6357oid
Title:: NGC 6357/Pismis 24 Chandra Point Source Optical/IR Identifications Catalog
Short Name:: NGC6357OID
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: Circumstellar disks are expected to evolve quickly in massive young clusters harboring many OB-type stars. Two processes have been proposed to drive the disk evolution in such cruel environments: (1) gravitational interaction between circumstellar disks and nearby passing stars (stellar encounters), and (2) photoevaporation by UV photons from massive stars. The relative importance of both mechanisms is not well understood. Studies of massive young star clusters can provide observational constraints on the processes of driving disk evolution. The authors investigate the properties of young stars and their disks in the NGC 6357 complex, concentrating on the most massive star cluster within the complex: Pismis 24. They use infrared data from the 2MASS and Spitzer GLIMPSE surveys, complemented with their own deep Spitzer imaging of the central regions of Pismis 24, in combination with X-ray data to search for young stellar objects (YSOs) in the NGC 6357 complex. The infrared data constrain the disk presence and are complemented by optical photometric and spectroscopic observations, obtained with VLT/VIMOS, that constrain the properties of the central stars. For those stars with reliable spectral types, they combine spectra and photometry to estimate the masses and ages. For cluster members without reliable spectral types, they obtain the mass and age probability distributions from R and I-band photometry, assuming these stars have the same extinction distribution as those in the "spectroscopic" sample. The authors compare the disk properties in the Pismis 24 cluster with those in other clusters/star-forming regions employing infrared color-color diagrams. The authors discover two new young clusters in the NGC 6357 complex. They give a revised distance estimate for Pismis 24 of 1.7 +/- 0.2 kpc. They also find that the massive star Pis 24-18 is a binary system, with the secondary being the main X-ray source of the pair. The authors provide photometry in 9 bands between 0.55 and 8 micron (µm) for the members of the Pismis 24 cluster. They derive the cluster mass function and find that up to the completeness limit at low masses it agrees well with the initial mass function of the Trapezium cluster. They derive a median age of 1 Myr for the Pismis 24 cluster members. The R-band observations were performed on 2008 April 1 and 6, and the I-band observations were done on 2008 May 1, both using the VIMOS instrument on the VLT. The near-IR photometry in the J, H and Ks bands were taken from the 2MASS. The mid-IR photometry at 3.6, 4.5, 5.8 and 8.0 um were obtained withe the Spitzer IRAC camera, both from the GLIMPSE I survey and from deep observations of the central Pismis 24 region carried out by the authors on 2006 September 29. The X-ray observations were made by the Chandra ACIS-I instrument and previously published by Wang et al. (2007, ApJS, 168, 100: the HEASARC NGC6357CXO table). The X-ray sources were matched to sources detected in the VIMOS R and I bands based on positional coincidence, using a 1.5 arcseconds tolerance. The accuracy of the optical and X-ray positions was 0.6 and 1.0 arcseconds, respectively. Given the high space density of sources in the central regions of Pismis 24, there may be a substantial number (up to 1/6 of the sources) of "false positives", according to the authors. This table contains the list of 643 optical/IR counterparts to the Chandra X-ray sources found by Wang et al. (2007) which were identified by the present authors: for 136 of the 779 X-ray sources, no counterparts were found. This table was created by the HEASARC in March 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/539/A119">CDS Catalog J/A+A/539/A119</a> files table1.dat and table3.dat. This is a service provided by NASA HEASARC .

609. NGC 2244/Rosette Nebula Chandra X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc2244cxo
Title:: NGC 2244/Rosette Nebula Chandra X-Ray Point Source Catalog
Short Name:: NGC2244CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains the point source catalog based on the first high spatial resolution X-ray study of NGC 2244, the 2 Myr old stellar cluster in the Rosette Nebula, using Chandra. Over 900 X-ray sources are detected within 20 arcminutes of the cluster central position (J2000.0 RA and Dec of 6 31 59.9, +4 55 36); 77% of these X-ray sources have optical or FLAMINGOS NIR stellar counterparts and are mostly previously uncataloged young cluster members. The X-ray-selected population is estimated to be nearly complete between 0.5 and 3 Msolar. A number of further results emerge from the analysis: (1) The X-ray luminosity function (XLF) and the associated K-band LF indicate a normal Salpeter IMF for NGC 2244. This is inconsistent with the top-heavy IMF reported from earlier optical studies that lacked a good census of < 4 Msolar stars. By comparing the NGC 2244 and Orion Nebula Cluster XLFs, the authors estimate a total population of ~2000 stars in NGC 2244. (2) The spatial distribution of X-ray stars is strongly concentrated around the central O5 star, HD 46150. The other early O star, HD 46223, has few companions. The cluster's stellar radial density profile shows two distinctive structures: a power-law cusp around HD 46150 that extends to ~0.7 pc, surrounded by an isothermal sphere extending out to 4 pc with core radius 1.2 pc. This double structure, combined with the absence of mass segregation, indicates that this 2 Myr old cluster is not in dynamical equilibrium. (3) The fraction of X-ray-selected cluster members with K-band excesses caused by inner protoplanetary disks is 6%, slightly lower than the 10% disk fraction estimated from the FLAMINGOS study based on the NIR-selected sample. (4) X-ray luminosities for 24 stars earlier than B4 confirm the long-standing log (LX/Lbol) ~ -7 relation. The Rosette OB X-ray spectra are soft and consistent with the standard model of small-scale shocks in the inner wind of a single massive star. This table was created by the HEASARC in July 2008 based on electronic versions of Tables 2, 3, 4, 5 and 6 of the reference paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .

610. NGC 253 XMM-Newton X-Ray Point Source Catalog

ID:: ivo://nasa.heasarc/ngc253xmm
Title:: NGC 253 XMM-Newton X-Ray Point Source Catalog
Short Name:: NGC253XMM
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains the NGC 253 XMM-Newton X-Ray Point Source Catalog. NGC 253 is a local, starbursting spiral galaxy with strong X-ray emission from hot gas, as well as many point sources. The authors have conducted a spectral survey of the X-ray population of NGC 253 using a deep XMM-Newton observation. NGC 253 only accounts for ~20 per cent of the XMM-Newton EPIC field of view, allowing them to identify ~ 100 X-ray sources that are unlikely to be associated with NGC 253. Hence, they were able to make a direct estimate of contamination from, for example, foreground stars and background galaxies. X-ray luminosity functions (XLFs) of galaxy populations are often used to characterize their properties. There are several methods for estimating the luminosities of X-ray sources with few photons. The authors have obtained spectral fits for the brightest 140 sources in the 2003 XMM-Newton observation of NGC 253, and compare the best-fitting luminosities of those 69 non-nuclear sources associated with NGC 253 with luminosities derived using other methods. They find the luminosities obtained from these various methods to vary systematically by a factor of up to 3 for the same data; this is largely due to differences in absorption. The authors therefore conclude that assuming Galactic absorption is probably unwise; rather, one should measure the absorption for the population. In addition, they find that standard estimations of the background contribution to the X-ray sources in the field are insufficient, and that the background active galactic nuclei (AGN) may be systematically more luminous than previously expected. However, the excess in their measured AGN XLF with respect to the expected XLF may be due to an as yet unrecognized population associated with NGC253. XMM-Newton observations are susceptible to periods of high background levels, caused by increased flux of solar particles. The authors screened the data from each of the EPIC cameras (MOS1, MOS2 and pn), to remove flaring intervals. This process resulted in ~ 46 ks of good time for the pn and ~ 69 ks for the MOS cameras. The authors combined the cleaned MOS and pn data, and ran the source detection algorithm provided with the XMM-Newton data analysis suite SAS version 7.0. They accepted sources with maximum-likelihood detections > 10 (equivalent to 4 sigma). This table was created by the HEASARC in April 2009 based on the electronic version of Tables A1 and A2 from the paper which were obtained from the CDS (their catalog J/MNRAS/388/849 files tablea1.dat and tablea2.dat). This is a service provided by NASA HEASARC .

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601. NGC 3293 Chandra X-Ray Point Source Catalog

602. NGC 4636 Chandra X-Ray Point Source Catalog

603. NGC 6231 Chandra X-Ray Point Source Catalog

604. NGC 1399 Chandra X-Ray Source Catalog

605. NGC 2516 Cluster XMM-Newton X-Ray Point Source Catalog

606. NGC2000.0: Complete New General Catalog and Index Catalog

607. NGC 1512/NGC 1510 XMM-Newton X-Ray Point Source Catalog

608. NGC 6357/Pismis 24 Chandra Point Source Optical/IR Identifications Catalog

609. NGC 2244/Rosette Nebula Chandra X-Ray Point Source Catalog

610. NGC 253 XMM-Newton X-Ray Point Source Catalog

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