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571. NGC 1332 Chandra X-Ray Compact Source Catalog
ID:
ivo://nasa.heasarc/ngc1332cxo
Title:
NGC 1332 Chandra X-Ray Compact Source Catalog
Short Name:
NGC1332CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
Chandra ACIS-S3 (Advanced CCD Imaging Spectrometer) observations of the nearby S0 galaxy NGC 1332 resolve much of the X-ray emission into 73 point sources, of which 37 lie within the D<sub>25</sub> isophote. The remaining galaxy emission comprises hot, diffuse gas and unresolved sources and is discussed in two companion papers. The point-source X-ray luminosity function (XLF) shows the characteristic break seen in other early-type galaxies at ~2 x 10<sup>38</sup> ergs s<sup>-1</sup>. After applying corrections for detection incompleteness at low luminosities due to source confusion and contamination from diffuse galactic emission, the break vanishes and the data are well described as a single power law. This result casts further doubt on there being a "universal" XLF break in early-type galaxies, marking the division between neutron star and black hole systems. The logarithmic slope of the differential XLF (dN/dL), beta = 2.7 +/- 0.5, is marginally (~2.5 sigma) steeper than has been found for analogous completeness-corrected fits of other early-type galaxies but closely matches the behavior seen at high luminosities in these systems. Two of the sources within D<sub>25</sub> are ultraluminous X-ray sources (ULXs), although neither have LX > 2 x 10<sup>39</sup> ergs s<sup>-1</sup>. The absence of very luminous ULXs in early-type galaxies suggests a break in the XLF slope at ~1-2 x 10<sup>39</sup> ergs s<sup>-1</sup>, although the data were not of sufficient quality to constrain such a feature in NGC 1332. The sources have a spatial distribution consistent with the optical light and display a range of characteristics that are consistent with an LMXB population. The general spectral characteristics of the individual sources, as well as the composite source spectra, are in good agreement with observations of other early-type galaxies, although a small number of highly absorbed sources are seen. Two sources have very soft spectra, two show strong variability, indicating compact binary nature, and one source shows evidence of an extended radial profile. The authors do not detect a central source in NGC 1332, but find a faint (L<sub>X</sub> = 2 +/- 1 x 10<sup>38</sup> ergs s<sup>-1</sup>) point source coincident with the center of the companion dwarf galaxy NGC 1331. The region of sky containing NGC 1332 was observed with the ACIS instrument aboard Chandra between 2002 September 19 10:39 and September 20 02:59 UTC for a nominal ~60 ksec exposure.. This table contains the 73 bona fide X-ray compact sources detected in this observation, excluding one source centered within 1" of the galaxy centroid that is actually the central part of the diffuse galactic emission, one source within the D<sub>25</sub> isophote of the neighboring galaxy NGC 1331, and one source with no photons within the 0.5-7.0 keV band which is likely to be spurious. The spatial extent of 72 of the 73 sources is consistent with the instrumental PSF. One source (number 14) is clearly more extended than the PSF. This table was created by the HEASARC in May 2018 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/612/848">CDS Catalog J/ApJ/612/848</a> file table1.dat, the list of detected X-ray sources in the Chandra observation of NGC 1332. This is a service provided by NASA HEASARC .
572. NGC 4649 Chandra X-Ray Discrete Source Catalog
ID:
ivo://nasa.heasarc/ngc4649cxo
Title:
NGC 4649 Chandra X-Ray Discrete Source Catalog
Short Name:
NGC4649CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The authors performed a Chandra X-ray observation of the X-ray bright E2 elliptical galaxy NGC 4649 (M 60). In addition to bright diffuse emission, they resolved 165 discrete sources, most of which are presumably low-mass X-ray binaries (LMXBs). As found in previous studies, the luminosity function of the resolved sources is well-fitted by a broken power law. In NGC 4697 and NGC 1553, the break luminosity was comparable to the Eddington luminosity of a 1.4 solar mass neutron star. One possible interpretation of this result is that those sources with luminosities above the break are accreting black holes and those below are mainly accreting neutron stars. The total X-ray spectrum of the resolved sources is well fitted by a hard power law. NGC 4649 was observed on 2000 April 20 on the ACIS-S3 CCD operated at a temperature of -120 C and with a frame time of 3.2 s. In addition to the S3 chip, the ACIS chips I2, I3, S1, S2, and S4 were also turned on for the duration of the observation. Although a number of serendipitous sources were seen on the other chips, the analysis of NGC 4649 in this paper was based on data from the S3 chip alone. The total exposure for the S3 chip was 36,780 s. The discrete X-ray source population on the ACIS S3 image was determined using a wavelet detection algorithm in the 0.3 - 10.0 keV band, and they were confirmed with a local cell detection method. The authors used the CIAO, WAVDETECT, and CELLDETECT programs. The high spatial resolution of Chandra implies that the sensitivity to point sources is not affected very strongly by the background. Thus, the source detection was done using the entire exposure of 36,780 s, including periods with background flares. The wavelet source detection significance threshold was set at 10<sup>-6</sup>, which implies that less than 1 false source (due to a statistical fluctuation in the background) would be detected in the entire S3 image. This significance threshold approximately corresponds to requiring that the source flux be determined to better than 3 sigma. This table was created by the HEASARC in April 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/600/729">CDS catalog J/ApJ/600/729</a> file table1.dat. This is a service provided by NASA HEASARC .
573. NGC 1600 Chandra X-Ray Discrete Source Catalog
ID:
ivo://nasa.heasarc/ngc1600cxo
Title:
NGC 1600 Chandra X-Ray Discrete Source Catalog
Short Name:
NGC1600CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The authors observed the X-ray-bright E3 galaxy NGC 1600 and nearby members of the NGC 1600 group with the Chandra X-Ray Observatory ACIS-S3 to study their X-ray properties. NGC 1600 is the brightest member of the NGC 1600 group; NGC 1601 (1.6 arcminutes away) and NGC 1603 (2.5 arcminutes away) are the two nearest galaxies, both of which are non-interacting members. The authors adopted the 2MASS Point Source Catalog position of J2000.0 RA = 04<sup>h</sup> 31<sup>m</sup> 39.87<sup>s</sup>, Dec = -05<sup>o</sup> 05' 10.5" as the location of the center of the NGC 1600 galaxy. Unresolved emission dominates the Chandra observation; however, some of the emission is resolved into 71 sources, most of which are low-mass X-ray binaries associated with NGC 1600. Twenty-one of the sources have L<sub>X</sub> > 2 x 10<sup>39</sup> ergs/s (0.3-10.0 keV; assuming they are at the distance of NGC 1600 of 59.98 Mpc), marking them as ultraluminous X-ray point source (ULX) candidates. NGC 1600 may have the largest number of ULX candidates in an early-type galaxy to date; however, cosmic variance in the number of background active galactic nuclei cannot be ruled out. The spectrum and luminosity function (LF) of the resolved sources are more consistent with sources found in other early-type galaxies than with sources found in star-forming regions of galaxies. The source LF and the spectrum of the unresolved emission both indicate that there are a large number of unresolved point sources. The authors propose that these sources are associated with globular clusters (GCs) and that NGC 1600 has a large GC specific frequency. Observations of the GC population in NGC 1600 would be very useful for testing this prediction. NGC 1600 was observed in two intervals on 2002 September 18-19 (ObsID 4283) and 2002 September 20 (ObsID 4371) with live exposures of 26,783 and 26,752 s, respectively. The first observation showed clear evidence of a major background "flare" in the first 20% of the observation. The second observation had some small fluctuations greater than 20% from the mean rate. After these were filtered, observations 4283 and 4371 had flare-free exposure times of 21,562 and 23,616 s, respectively. This table lists all 71 discrete sources detected by wavdetect over the 0.3-6 keV energy range in the combination of the two observations. The first 3 sources (source numbers 1, 2 and 3) are clearly extended according to the authors. The authors expect 11 +/- 2 foreground/background sources to be present based on the source counts in Brandt et al. (2000, AJ, 119, 2349) and Mushotzky et al. (2000, Nature, 404, 459). The authors determined the observed X-ray hardness ratios for the sources, using the same techniques that they have used previously. They define three hardness ratios as H21 = (M-S)/(M+S), H31 = (H-S)/(H+S), and H32 = (H-M)/(H+M), where S,M, and H are the total counts in the soft (0.3-1 keV), medium (1-2 keV) and hard (2-6 keV) respectively. From their previous definitions, they have reduced the hard band from 2-10 to 2-6 keV: since the 6-10 keV range is dominated by background photons for most sources, this should increase the S/N of the hardness ratio techniques. The hardness ratios measure observed counts, which are affected by Galactic absorption and quantum efficiency (QE) degradation in the Chandra ACIS detectors. In order to compare with other galaxies, it is useful to correct the hardness ratios for these two soft X-ray absorption effects. Therefore, the authors have calculated the intrinsic hardness ratios, denoted by a superscript 0, using a correction factor in each band appropriate to the best-fit spectrum of the resolved sources, and these are what are quoted in this table. This table was created by the HEASARC in May 2018 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/617/262/">CDS Catalog J/ApJ/617/262/</a> file table1.dat, the list of detected discrete X-ray sources in the Chandra observation of the NGC 1600 group. This is a service provided by NASA HEASARC .
574. NGC 2808 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc2808cxo
Title:
NGC 2808 Chandra X-Ray Point Source Catalog
Short Name:
NGC2808CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the sources detected in a Chandra X-ray observation of the Galactic globular cluster NGC 2808, as well as the corresponding XMM-Newton data for those sources which have XMM-Newton X-ray counterparts. Using new Chandra X-ray observations and existing XMM-Newton X-ray and Hubble Space Telescope far-ultraviolet observations, the authors aim to detect and identify the faint X-ray sources belonging to NGC 2808 in order to understand their role in the evolution of globular clusters. The authors classify the X-ray sources associated with the cluster by analysing their colors and variability. Previous observations with XMM-Newton and far-ultraviolet observations with Hubble are re-investigated to help identify the Chandra sources associated with the cluster. The authors compare their results to population synthesis models and observations of other Galactic globular clusters. NGC 2808 was observed with the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer-Imager (ACIS-I) on 2007 June 19-21 (28 months after the XMM-Newton observation referred to the reference paper) for two distinct exposures of 46 and 11 kiloseconds. The authors detect 113 sources, of which 16 fall inside the half-mass radius of NGC 2808 and are concentrated towards the cluster core. This table was created by the HEASARC in February 2009 based on the electronic version of Table 1 from the paper which was obtained from the CDS (their catalog J/A+A/490/641 file table1.dat). This is a service provided by NASA HEASARC .
575. 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:
25 Apr 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 .
576. NGC 2237 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc2237cxo
Title:
NGC 2237 Chandra X-Ray Point Source Catalog
Short Name:
NGC2237CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The authors have obtained high spatial resolution Chandra X-ray images of the NGC 2237 young stellar cluster on the periphery of the Rosette Nebula. They detect 168 X-ray sources, 80% of which have stellar counterparts in USNO, Two Micron All Sky Survey, and deep FLAMINGOS images. These constitute the first census of the cluster members with 0.2 <~ M <~ 2 M<sub>sun</sub>. Star locations in near-infrared color-magnitude diagrams indicate a cluster age of around 2 Myr with a visual extinction of 1 <~ AV <~ 3 at 1.4 kpc, the distance of the Rosette Nebula's main cluster NGC 2244. The authors derive the K-band luminosity function and the X-ray luminosity function of the cluster, which indicate a population of ~ 400-600 stars. The X-ray-selected sample shows a K-excess disk frequency of 13%. The young Class II counterparts are aligned in an arc ~3 pc long suggestive of a triggered formation process induced by the O stars in NGC 2244. The diskless Class III sources are more dispersed. Several X-ray emitting stars are located inside the molecular cloud and around gaseous pillars projecting from the cloud. These stars, together with a previously unreported optical outflow originating inside the cloud, indicate that star formation is continuing at a low level and the cluster is still growing. This X-ray view of young stars on the western side of the Rosette Nebula complements the authors' earlier studies of the central cluster NGC 2244 and the embedded clusters on the eastern side of the Nebula. The large-scale distribution of the clusters and molecular material is consistent with a scenario in which the rich central NGC 2244 cluster formed first, and its expanding H II region triggered the formation of the now-unobscured satellite clusters Rosette Molecular Cloud (RMC) XA and NGC 2237. A large swept-up shell of material around the H II region is now in a second phase of collect-and-collapse fragmentation, leading to the recent formation of subclusters. Other clusters deeper in the molecular cloud appear unaffected by the Rosette Nebula expansion. Some sources which have information from published catalogs are listed by their source_number value below, where for convenience, [OI81] = Ogura & Ishida (1981, PASJ, 33, 149), [MJD95] = Massey, Johnson, & Degioia-Eastwood (1995, ApJ, 454, 151) and [BC02] = Berghofer & Christian (2002, A&A, 384, 890): <pre> 53 = [OI81] 14 = [MJD95] 104; spectral type B1V; pmRA=11.0 mas/yr, pmDE=-2.8 mas/yr; 54 = [OI81] 10 = [MJD95] 108; spectral type B2V; pmRA=-2.3 mas/yr, pmDE=-11.9 mas/yr; 61 = V539 Mon [OI81] 13 = [MJD95] 110; MSX6C G206.1821-02.3456; pmRA=2.8 mas/yr, pmDE=0.4 mas/yr; 71 = [OI81] 12 = [MJD95] 102; pmRA=6.8 mas/yr, pmDE=0.6 mas/yr; 128 = [OI81] 35 = [MJD95] 471; spectral type A2:; pmRA=-0.8 mas/yr, pmDE=3.6 mas/yr; 138 = [OI81] 36 = [MJD95] 497; spectral type B5; pmRA=6.5 mas/yr, pmDE=2.1 mas/yr; 141 = [MJD95] 498; pmRA=-3.0 mas/yr, pmDE=1.9 mas/yr; 149 = [BC02] 11; known X-ray source; log(Lx(ROSAT/PSPC))=31.01 erg/s; pmRA=0.6 mas/yr, pmDE=-12.6 mas/yr; 161 = [MJD95] 653; pmRA=-1.0 mas/yr, pmDE=-5.4 mas/yr </pre> This table was created by the HEASARC in July 2010 based on electronic versions of Tables 1, 2, 3 and 4 of the reference paper which were obtained from the electronic ApJ web site. To distinguish between the 130 X-ray sources in the primary sample (Table 1 of the reference paper) and the 38 X-ray sources in the tentative sample (Table 2 of the reference paper), the HEASARC has created a parameter called source_sample which is set to 'P' for the primary sources and to 'T' for the tentative sources. This is a service provided by NASA HEASARC .
577. NGC 6530 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc6530cxo
Title:
NGC 6530 Chandra X-Ray Point Source Catalog
Short Name:
NGC6530CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
In a deep 60 ks Chandra ACIS-I X-ray observation of the very young (~ 1.5 - 2.0 Myr) cluster NGC 6530 on 2001 Jun 18-19, the authors have detected 884 X-ray point sources and argue that a very large fraction of them (90%-95%) must be pre-main-sequence (PMS) cluster members, mostly low-mass stars. This is a significant enlargement of the known NGC 6530 stellar population with respect to previous optical studies, including H-alpha surveys. They identify 220 X-ray sources with catalogued stars down to V = 17, while most unidentified sources have fainter counterparts. Moreover, they find an infrared counterpart in the 2MASS (CDS. No. <II/246>) Catalog for 731 X-ray sources. The optically identified cluster X-ray sources are found in a band in the H-R diagram above the main sequence, in the locus of 0.5 - 1.5 Myr PMS stars, with masses down to 0.5 - 1.5 solar masses (M_sun). The pointing direction for the Chandra observation was the NGC 6530 cluster center at RA = 18^h 04^m 24.38^s, Dec = -24^o 21' 05.8" (J2000.0). The PWDetect algorithm found 884 X-ray point sources in the ACIS-I image above a detection significance threshold chosen to ensure only 1 spurious detection on the average. The Sung et al. (2000, AJ, 120, 333; <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/120/333">CDS Cat. <J/AJ/120/333></a>) = SCB Catalog of optical objects against which the X-ray point source list was compared doed not cover the easternmost 2.25' of the ACIS FOV (RAs later than 18^h 04^m 52^s), notice, which comprises about 13% of the ACIS FOV. There are 46 detected X-ray sources (5.2% of the total) in the area not covered by the SCB Catalog. A matching distance of 4 times the X-ray error radius or 2.0" (whichever is greater) was used to identify optical counterparts to the X-ray sources, after a systematic shift between the X-ray and optical positions of -0.4" and 1.84" in RA and declination, respectively, was applied. The authors estimate that as many as 28 of their 220 optical identifications may be spurious, preferentially those in the outer parts of the FOV where the positional uncertainties are larger. There are 8792 'good' 2MASS sources in the ACIS FOV. A matching distance of 4 times the X-ray error radius or 1.5" (whichever is greater) was used to identify 2MASS counterparts to the X-ray sources, after systematic corrections of 0.3" and 1.75" in RA and declination, respectively, were applied to the 'raw' X-ray positions. There are 13 cases where there are two possible IR counterparts to a single X-ray source, and 2 cases where there are three possible IR Counterparts to a single X-ray source. (Notice that, in such cases, this table contains multiple entries, one for each counterpart, and hence there are 901 entries compared to 884 X-ray sources.) The authors conclude that the plausible number of spurious X-ray-2MASS identifications is between 30 and 50. Overall, there remain 146 X-ray sources with no optical or IR identification. This table was created by the HEASARC in December 2006 based on CDS table J/ApJ/608/781, the file table1.dat. This is a service provided by NASA HEASARC .
578. NGC 300 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc300cxo
Title:
NGC 300 Chandra X-Ray Point Source Catalog
Short Name:
NGC300CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the source catalog from a new Chandra ACIS-I observation of the nearby (2.0 Mpc) SA(s)d spiral galaxy NGC 300 which was obtained as part of the Chandra Local Volume Survey (CLVS). This 63-ks exposure covers ~88% of the D<sub>25</sub> isophote (R ~ 6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance down to a limiting unabsorbed 0.35-8 keV luminosity of ~ 10<sup>36</sup> erg/s. Sources were cross-correlated with a previous XMM-Newton catalog, and the authors find 75 "X-ray transient candidate" sources that were detected by one observatory, but not the other. They derive an X-ray scale length of 1.7 +/- 0.2 kpc and a recent star formation rate of 0.12 M<sub>sun</sub>/yr in excellent agreement with optical observations. Deep, multi-color imaging from the Hubble Space Telescope, covering ~ 32% of this Chandra field, was used to search for optical counterparts to the X-ray sources, and the authors have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background active galactic nucleus candidates. In the reference paper, the authors present the X-ray luminosity functions (XLFs) at different X-ray energies, and find the total NGC 300 X-ray point-source population to be consistent with other late-type galaxies hosting young stellar populations (<~ 50 Myr). They find that the XLF of sources associated with older stellar populations has a steeper slope than the XLF of X-ray sources coinciding with young stellar populations, consistent with theoretical predictions. NGC 300 was observed on 2010 September 25 for 63 ks using ACIS-I during the Chandra X-Ray Observatory Cycle 12, observation ID 12238. The source detection strategy that was used is described in Section 2.3 of the reference paper. ACIS-Extract (AE) was run a final time on the source list that was produces after an initial run of wavdetect followed by several iterations of AE, and the Poisson probability of not being a source (pns) value was computed in each of the following nine energy bands: 0.5 - 8.0, 0.5 - 2.0, 2.0 - 8.0, 0.5 - 1.0, 1.0 - 2.0, 2.0 - 4.0, 4.0 - 8.0, 0.35 - 1.0 and 0.35 - 8.0 keV. To be included in the final NGC 300 catalog, a source was required to have a pns value less than 4 x 10<sup>-6</sup> in any of the nine energy bands; if only the 0.35 - 8 keV band were considered, ~4% of significant sources would have been lost. The final CLVS source catalog for NGC 300 contains 95 sources. This table was initially created by the HEASARC in September 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/758/15/">CDS Catalog J/ApJ/758/15/</a> files table4.dat, table5.dat, table6.dat and table7.dat containing the X-ray properties of the 95 Chandra point sources found in this study. The information on the optical counterparts to (some of) the Chandra X-ray sources and on the X-ray point source classification (presented in Tables 16 and 17, respectively, of the reference paper) is not included herein. It was updated in September 2015 to include the unabsorbed 0.35-8.0 keV energy fluxes (in the parameter herein called b4_flux) from the second reference paper. This is a service provided by NASA HEASARC .
579. NGC 2362 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc2362cxo
Title:
NGC 2362 Chandra X-Ray Point Source Catalog
Short Name:
NGC2362CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the results of an observation of the young cluster NGC 2362 in X-rays with Chandra ACIS-I in which 387 point X-ray sources, most of which are shown to be cluster members, were detected using PWDetect, a wavelet-based source detection algorithm, with a detection threshold chosen to ensure no more than one spurious detection in the entire ACIS FOV. The table lists all of the detected X-ray sources and their basic X-ray properties, as well as their proposed identifications with optical stars, using data from Moitinho et al. (2001ApJ...563L..73M; UBVRI photometry) and Dahm (2005, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/130/1805">CDS Cat. <J/AJ/130/1805></a>; H-alpha data), as well as newer photometric data from Moitinho et al. (2005, in 'Cores to Clusters' [A&SSL, 324], 167). A matching position of less than 4 times the X-ray positional uncertainty of the X-ray source from PWDetect was used. Also included in the table is a classification of the optically-identified X-ray sources, based on their positions in the HR Diagram, which helps to separate rather clearly the cluster members from interloping field objects. This table was created by the HEASARC in March 2007 based on CDS table J/A+A/460/133 files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
580. NGC 5866 Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/ngc5866cxo
Title:
NGC 5866 Chandra X-Ray Point Source Catalog
Short Name:
NGC5866CXO
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
S0 galaxies are often thought to be passively evolved from spirals after star formation is quenched. To explore what is actually occurring in such galaxies, the authors conducted a multi-wavelength case study of NGC 5866 - a nearby edge-on S0 galaxy in a relatively isolated environment. This study shows strong evidence for dynamic activities in the interstellar medium, which are most likely driven by supernova explosions in the galactic disk and bulge. Understanding these activities can have strong implications for studying the evolution of such galaxies. The authors utilized Chandra, Hubble Space Telescope, and Spitzer data as well as ground-based observations to characterize the content, structure, and physical state of the medium and its interplay with the stellar component in NGC 5866. These reveal the presence of diffuse X-ray-emitting hot gas, which extends as far as 3.5 kpc away from the galactic plane and can be heated easily by Type Ia SNe in the bulge. The Chandra/ACIS observation of NGC 5866 was taken on 2002 November 14. The authors reprocessed the archived data for their study. See Figure 1 in the reference paper for the Chandra/ACIS-S image of NGC 5866 in the 0.3-7 keV band. This table contains the detected X-ray point sources listed in table 2 of this paper. This table was created by the HEASARC in May 2018 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/706/693">CDS Catalog J/ApJ/706/693</a> file table2.dat, the list of detected X-ray sources in the Chandra observation of NGC 5866. This is a service provided by NASA HEASARC .