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ASCA Galactic Plane Survey of Faint X-Ray Sources
Sugizaki et al. (2001) have published a study of faint X-ray sources that were resolved in the ASCA Galactic Plane Survey and their contribution to the galactic ridge X-ray emission, and the present database contains their list of discrete sources. The X-ray emission from the central region of the Galactic plane, |l|<~45 degrees and |b|<~0.4 degrees, was studied in the 0.7 to 10 keV energy band with a spatial resolution of ~3' with the Advanced Satellite for Cosmology and Astrophysics (ASCA) observatory. The authors developed a new analysis method for the ASCA data to resolve discrete sources from the extended Galactic ridge X-ray emission (GRXE). Using the ASCA Gas Imaging Spectrometers (GISs), they successfully resolved 163 discrete sources with X-ray fluxes down to 10<sup>-12</sup>.5<sup>ergs/cm</sup>2/s and determined the intensity variations of the GRXE as a function of the Galactic longitude with a spatial resolution of about 1 degree. This database was created by the HEASARC in December 2001 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/134/77/table2">CDS Catalog J/ApJS/134/77/table2</a>.dat. This is a service provided by NASA HEASARC .
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Chandra Typical Galactic Plane Region Point Source Catalog
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Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), the authors carried out a deep hard X-ray observation of the Galactic plane region at a location (l, b) ~ (28.5 degrees, 0.0 degrees), where no discrete X-ray source had been reported previously. They detected 274 new point X-ray sources (4-sigma or greater confidence in any of the 3 energy bands 0.5 - 3.0 keV, 3.0 - 8.0 keV or 0.5 - 8.0 keV), as well as strong Galactic diffuse emission within two partially overlapping ACIS-I fields (~ 250 square arcminutes in total). The point-source sensitivity was ~ 3 x 10-15 ergs/s/cm2 in the 2 - 10 keV band and ~ 2 x 10-16 erg/s/cm2 in the 0.5 - 2 keV band The sum of all the detected point-source fluxes accounts for only ~ 10% of the total X-ray flux in the field of view. Only 26 point sources were detected in both the soft and hard bands, indicating that there are two distinct classes of X-ray source distinguished by their spectral hardness ratios. The surface number density of the hard sources is only slightly higher than that measured in high Galactic latitude regions, indicating that the majority of the hard sources are background AGNs. Following up the Chandra observation, the authors performed a near-infrared (NIR) survey with SofI at ESO/NTT. Almost all the soft X-ray sources have been identified in the NIR, and their spectral types are consistent with main-sequence stars, suggesting that most of them are nearby X-ray-active stars. On the other hand, only 22% of the hard sources had near-IR counterparts, which are presumably Galactic. From X-ray and near-IR spectral study, they are most likely to be quiescent cataclysmic variables. This Browse table was created by the HEASARC in December 2006 based on CDS Catalog J/ApJ/635/214/, the file table1.dat. This is a service provided by NASA HEASARC .
NGC 1332 Chandra X-Ray Compact Source Catalog
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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 D25 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 1038 ergs s-1. 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 D25 are ultraluminous X-ray sources (ULXs), although neither have LX > 2 x 1039 ergs s-1. The absence of very luminous ULXs in early-type galaxies suggests a break in the XLF slope at ~1-2 x 1039 ergs s-1, 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 (LX = 2 +/- 1 x 1038 ergs s-1) 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 D25 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 CDS Catalog J/ApJ/612/848 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 .
Spitzer Wide-Area IR Extra-Galactic Survey Chandra X-Ray Sources
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This table contains results from deep combined observations with Spitzer and Chandra of the Spitzer Wide-Area Infrared Extragalactic Survey (SWIRE) in the ELAIS N1 region. This survey was used to investigate the nature of the faint X-ray and IR sources in common, to identify active galactic nucleus (AGN)/starburst diagnostics, and to study the sources of the X-ray and cosmic infrared backgrounds (XRB and CIRB). In the 17' x 17' area of the Chandra ACIS-I image there were approximately 3400 SWIRE near-IR sources with 4-sigma detections in at least two Infrared Array Camera (IRAC) bands and 988 sources detected at 24 micron (µm) with the Multiband Imaging Photometer (MIPS) brighter than a 24-um flux S_24 ~ 0.1 mJy. Of these, 102 IRAC and 59 MIPS sources have Chandra counterparts, out of a total of 122 X-ray sources present in the area with 0.5 - 8 keV flux > 10-15 erg cm-2 s-1. The SWIRE ELAIS N1 field was imaged by the IRAC multiband camera on Spitzer in 2004 January and with MIPS in early 2004 February. The observations were centered at the position (16h 00m, +59d 01'). The X-ray observations were taken as part of the ELAIS Deep X-ray Survey (EDXS) and are described in detail in Manners et al. (2003, MNRAS, 343, 293). For this analysis, the Chandra Advanced CCD Imaging Spectrometer (ACIS) observation of 75 ks centered on (16h 10m 20.11s, +54d 33' 22.3") (J2000.0) in the ELAIS N1 region. The aim point was focused on the ACIS-I chips, which consist of four CCDs arranged in a 2 x 2 array covering an area of 16.9' x 16.9' (286 square arcmin). Bad pixels and columns were removed, and data were filtered to eliminate high background times (due to strong solar flares), leaving 71.5 ks of good data after filtering. Counts-to-photon calibration assumed a standard power-law model spectrum with photon index Gamma = 1.7. Sources were detected to flux levels of 2.3 x 10-15 erg s-1 cm-2 in the 0.5 - 8 keV band, 9.4 x 10-16 erg s-1 cm-2 in the 0.5 - 2 keV band, and 5.2 x 10-15 erg s-1 cm-2 in the 2 - 8 keV band. Sources are detectable to these flux limits over 90% of the nominal survey area. For this analysis, the authors used sources detected in the full band of ACIS-I only, of which there are 122 in the N1 region. Of the 102 sources in common between Chandra and SWIRE, 83 have significant detections in the separate soft X-ray band (0.5 - 2 keV) and 64 are detected in the hard (2 - 8 keV) band. A simple near-neighbor search was performed to cross-correlate the Spitzer and Chandra source catalogs within the Chandra ACIS-I chip image, using a d = 5" search radius (roughly the quadratic sum of the astrometric errors). All together, the authors found reliably associated counterparts for 102 of the 122 Chandra sources (84% in total). The vast majority of these were detected with the IRAC channels 1 and 2 (3.6 and 4.5 um): 100 of the 122 Chandra sources in each case. As many as 59 Chandra objects are reliably associated with MIPS 24 um sources (all of them having IRAC counterparts), and just 1 had a MIPS 70 um counterpart. Of the 102 Spitzer-identified Chandra sources, three turned out to correspond to Galactic stars on the basis of their position on color-magnitude plots and optical morphology and were excluded from the subsequent analysis (and this table). This table was created by the HEASARC in March 2007 based on CDS catalog J/AJ/129/2074 file table2.dat, This is a service provided by NASA HEASARC .
NuSTAR Hard X-Ray Survey of the Galactic Center
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This table contains some of the the first survey results of hard X-ray point sources in the Galactic Center (GC) region obtained by NuSTAR. The authors have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. They identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x 1032 and ~8 x 1032 erg/s at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40% - 60%). Both spectral analysis and logN - logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single-temperature thermal plasma model or an average photon index of Gamma = 1.5 - 2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population. The observations of the GC region with NuSTAR began in 2012 July, shortly after its launch. The original survey strategy for the GC region was to match the central 2 degree x 0.7 degree region covered by the Chandra X-ray Observatory (Wang et al. 2002, Nature, 415, 148; Muno et al. 2009, ApJS, 181, 110). The field of views (FOVs) of neighboring NuSTAR observations in the survey were designed to overlap with each other by ~40%. Multiple observations of the same region with relatively large FOV offsets tend to average out the vignetting effects of each observation, enabling a more uniform coverage of the region. Multiple observations are also suitable for monitoring long term X-ray variability of sources in the region. Even when observing a single target, the NuSTAR observation is often broken up into two or more segments with relatively large pointing offsets to allow an efficient subtraction of a detector coordinate-dependent background component (e.g., Mori et al. 2013, ApJ, 770, L23). This table was created by the HEASARC in March 2018, based on CDS Catalog J/ApJ/825/132 files table2.dat, table3.dat, table4.dat and table5.dat. This is a service provided by NASA HEASARC .
ChIcAGO Survey Chandra X-Ray Source Catalog
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This table contains results from the 'Chasing the Identification of ASCA Galactic Objects' (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1. In ChIcAGO, the sub-arcsecond localization capabilities of Chandra have been combined with a detailed multi-wavelength follow-up program, with the ultimate goal of classifying the > 100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3 arcminutes of the original ASCA positions. The authors have identified infrared and optical counterparts to the majority of these sources, using both new observations and catalogs from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that emit in the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1 are active stellar coronae, massive stars with strong stellar winds that are possibly in colliding wind binaries, X-ray binaries, and magnetars. There is also another primary population that is still unidentified but, on the basis of its X-ray and infrared properties, likely comprises partly Galactic sources and partly active galactic nuclei. A total of 93 AGPS sources have been observed with Chandra as part of the ChIcAGO survey, of which 84 were imaged with ACIS-S and 9 were imaged with HRC-I. The ChIcAGO Chandra observations took place over a 3.5 yr period, from 2007 January to 2010 July. The Chandra exposure times ranged from ~ 1 to 10 ks. All the details of these Chandra observations are listed in Table 1 of the reference paper. The initial automated analysis of these Chandra observations was conducted using the ChIcAGO Multi-wavelength Analysis Pipeline (MAP), described in Section 2.2 of the reference paper. ChIcAGO MAP takes the ACIS-S or HRC-I Chandra observation of an AGPS source field and detects and analyzes all point sources within 3 arcminutes, equivalent to the largest likely position error, for the original AGPS source positions supplied by Sugizaki et al. (2001, ApJS, 134, 77). The authors then performed a more detailed X-ray analysis and counterpart study for those 74 sources with > 20 X-ray counts, as such sources are approximately within the original AGPS sources X-ray flux range (see Sections 3.2 and 3.3 of the reference paper). Infrared and optical follow-up were primarily performed on those ChIcAGO sources having > 20 X-ray counts. In order to determine which optical and infrared sources are counterparts to ChIcAGO sources, the authors used a technique similar to that described by Zhao et al. (2005, ApJS, 161, 429), using their Equation (11). If the separation between a ChIcAGO source's wavdetect position and its possible counterpart is less than the quadratic sum of their 3-sigma positional errors and the 3-sigma Chandra pointing error, then the X-ray and optical (or infrared) sources are likely to be associated. The 1-sigma positional errors for all sources in the 2MASS PSC and GLIMPSE catalogs are 0.1 arcseconds and 0.3 arcseconds, respectively. USNO B has an astrometric accuracy of < 0.25 arcseconds. The authors have assumed that the error distributions of the Chandra observations, Chandra pointing, and USNO B Catalog are all Gaussian for the purposes of identifying possible counterparts to the ChIcAGO sources. This table was created by the HEASARC in June 2014 based on electronic versions of Tables 1, 2 and 12 from the reference paper which were obtained from
XMM-Newton Survey Science Center Survey of the Galactic Plane
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Many different classes of X-ray sources contribute to the Galactic landscape at high energies. Although the nature of the most luminous X-ray emitters is now fairly well understood, the population of low-to-medium X-ray luminosity (LX = 1027 - 1034 erg/s) sources remains much less studied, our knowledge being mostly based on the observation of local members. The advent of wide-field and high-sensitivity X-ray telescopes such as XMM-Newton now offers the opportunity to observe this low-to-medium LX population at large distances. This study reports the results of a Galactic plane survey conducted by the XMM-Newton Survey Science Centre (SSC). Beyond its astrophysical goals, this survey aims at gathering a representative sample of identified X-ray sources at low latitude that can be used later on to statistically identify the rest of the serendipitous sources discovered in the Milky Way. The survey is based on 26 XMM-Newton observations, obtained at |b| < 20 degrees, distributed over a large range in Galactic longitudes and covering a summed area of 4 deg2. The flux limit of this survey is 2 x 10-15 erg/cm2/s in the soft (0.5 - 2 keV) band and 1 x 10-14 erg/cm2/s in the hard (2 - 1 2keV) band. A total of 1319 individual X-ray sources have been detected. Using optical follow-up observations supplemented by cross-correlation with a large range of multi-wavelength archival catalogs, the authors identify 316 X-ray sources. This constitutes the largest group of spectroscopically identified low-latitude X-ray sources at this flux level. The majority of the identified X-ray sources are active coronae with spectral types in the range A to M at maximum distances of ~1 kpc. The number of identified active stars increases towards late spectral types, reaching a maximum at K. Using infrared colors, the authors classify 18% of the stars as giants. The observed distributions of FX/FV, X-ray and infrared colors indicates that their sample is dominated by a young (100 Myr) to intermediate (600 Myr) age population with a small contribution of close main-sequence or evolved binaries. The authors find other interesting objects such as cataclysmic variables (d ~ 0.6 - 2 kpc), low-luminosity high-mass stars (likely belonging to the class of Gamma-Cas-like systems, d ~ 1.5 - 7 kpc), T Tauri and Herbig-Ae stars. A handful of extragalactic sources located in the highest Galactic latitude fields could be optically identified. For the 20 fields observed with the EPIC pn camera, the authors have constructed log N(>S) - log S curves in the soft and hard bands. In the soft band, the majority of the sources are positively identified with active coronae and the fraction of stars increases by about one order of magnitude from b = 60 degrees to b = 0 degrees at an X-ray flux of 2 x 10-14 erg/cm2/s. The hard band is dominated by extragalactic sources, but there is a small contribution from a hard Galactic population formed by CVs, HMXB candidates or Gamma-Cas-like systems and by some active coronal stars that are also detected in the soft band. At b = 0 degrees, the surface density of hard sources brighter than 1 x 10-13 erg/cm2/s steeply increases by one order of magnitude from l = 20 degrees to the Galactic center region (l = 0.9 degrees). This HEASARC table contains 739 X-ray sources detected in the 26 different fields observed in this study and listed in Tables 8 - 33, inclusive, of the reference paper. These 739 sources have the best XMM quality, i.e. the summary flag sum_flag which contains information about flags set automatically and manually for a given source is zero, meaning that there are no negative flags for the source detection, have either a 2MASS, USNO, GSC, or SDSS counterpart, whatever the probability of identification is, or have some information via SIMBAD or the authors own
NGC 2903 Central Region Chandra X-Ray Point Source Catalog
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This table contains some of the results from a deep Chandra observation of the central regions of the late-type barred spiral galaxy NGC 2903. The Chandra data reveal soft (kTe ~ 0.2 - 0.5 keV) diffuse emission in the nuclear starburst region and extending ~ 2' (~ 5 kpc) to the north and west of the nucleus. Much of this soft hot gas is likely to be from local active star-forming regions; however, besides the nuclear region, the morphology of hot gas does not strongly correlate with the bar or other known sites of active star formation. The central ~ 650 pc radius starburst zone exhibits much higher surface brightness diffuse emission than the surrounding regions and a harder spectral component in addition to a soft component similar to the surrounding zones. The authors interpret the hard component as also being of thermal origin with kTe ~ 3.6 keV and to be directly associated with a wind fluid produced by supernovae and massive star winds similar to the hard diffuse emission seen in the starburst galaxy M82. The inferred terminal velocity for this hard component, ~ 1100 km/s, exceeds the local galaxy escape velocity suggesting a potential outflow into the halo and possibly escape from the galaxy gravitational potential. Morphologically, the softer extended emission from nearby regions does not display an obvious outflow geometry. However, the column density through which the X-rays are transmitted is lower in the zone to the west of the nucleus compared to that from the east and the surface brightness is relatively higher suggesting some of the soft hot gas originates from above the disk: viewed directly from the western zone but through the intervening disk of the host galaxy along sight lines from the eastern zone. There are several point-like sources embedded in the strong diffuse nuclear emission zone. Their X-ray spectra show them to likely be compact binaries. None of these detected point sources are coincident with the mass center of the galaxy and the authors place an upper limit on the luminosity from any point-like nuclear source o < 2 x 1038 erg/s in the 0.5 - 8.0keV band, which indicates that NGC 2903 lacks an active galactic nucleus. Heating from the nuclear starburst and a galactic wind may be responsible for preventing cold gas from accreting onto the galactic center. NGC 2903, a nearby (8.9 Mpc, 1" = 43 pc) late-type barred SAB(rs)bc galaxy with strong circumnuclear star formation, was observed with Chandra using the ACIS-S instrument in imaging mode on 2010 March 7 (ObsID 11260). The source finding tool in lextrct (Tennant 2006, AJ, 132, 1372) was applied in the energy range of 0.5 - 8.0 keV in order to detect point sources inside the D25 isophote. A total of 92 point-like sources were detected with a signal-to-noise ratio (S/N) above 2.4 (see Tennant 2006) and with a minimum of 5 counts above the background uncertainty. This table contains this list of point-like sources. This table was created by the HEASARC in September 2014 based on CDS Catalog J/ApJ/758/105 file table3.dat. This is a service provided by NASA HEASARC .
Carina Nebula Chandra X-Ray Point Source Classes
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The Chandra Carina Complex Project (CCCP) provides a sensitive X-ray survey of a nearby starburst region over > 1 deg2 in extent. Thousands of faint X-ray sources are found, many concentrated into rich young stellar clusters. However, significant contamination from unrelated Galactic and extragalactic sources is present in the X-ray catalog. In their paper, the authors describe the use of a naive Bayes classifier to assign membership probabilities to individual sources, based on source location, X-ray properties, and visual/infrared properties. For the particular membership decision rule adopted, 75% of CCCP sources are classified as members, 11% are classified as contaminants, and 14% remain unclassified. The resulting sample of stars likely to be Carina members is used in several other studies, which appear in the special issue of Astrophysical Journal Supplement (Volume 194, May 2011 Issue) which was devoted to the CCCP. This table was created by the HEASARC in June 2011 based on the electronic version of Table 5 from the reference paper which was obtained from the ApJS web site. In the input source table, the names were truncated by 3 characters from their complete version. The HEASARC corrected these names, and also obtained the Chandra source positions, using the electronic version of Table 2 from the companion paper (Broos et al. 2011, ApJS, 194, 2: available as the HEASARC Browse table CARINACXO), also obtained from the ApJS web site. This is a service provided by NASA HEASARC .
Chandra Bulge Field X-Ray Point Source Catalog
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Apparently diffuse X-ray emission has been known to exist along the central quarter of the Galactic Plane since the beginning of X-ray astronomy; this is referred to as the Galactic Ridge X-ray emission (GRXE). Recent deep X-ray observations have shown that numerous X-ray point sources account for a large fraction of the GRXE in the hard band (2 - 8 keV). However, the nature of these sources is poorly understood. Using the deepest X-ray observations made in the Chandra bulge field, the authors present the result of a coherent photometric and spectroscopic analysis of individual X-ray point sources for the purpose of constraining their nature and deriving their fractional contributions to the hard-band continuum and Fe K line emission of the GRXE. Based on the X-ray color-color diagram, they divided the point sources into three groups: A (hard), B (soft and broad spectrum), and C (soft and peaked spectrum). The group A sources are further decomposed spectrally into thermal and non-thermal sources with different fractions in different flux ranges. From their X-ray properties, the authors speculate that the group A non-thermal sources are mostly active galactic nuclei and the thermal sources are mostly white dwarf (WD) binaries such as magnetic and non-magnetic cataclysmic variables (CVs), pre-CVs, and symbiotic stars, whereas the group B and C sources are X-ray active stars in flares and quiescence, respectively. In the log N - log S curve of the 2 - 8 keV band, the group A non-thermal sources are dominant above ~10-14 erg/cm2/s, which is gradually taken over by Galactic sources in the fainter flux ranges. The Fe K-alpha emission is mostly from the group A thermal (WD binaries) and the group B (X-ray active stars) sources. The authors retrieved 10 archived data sets of the Chandra bulge field (CBF) taken with the Advanced CCD Imaging Spectrometer-I (ACIS-I; 0.5 - 8.0 keV energy band with a spectral resolution of ~280 eV for the full width at half-maximum at 5.9keV) array on board Chandra. The observations were carried out from 2008 May to August with a total exposure time of ~900 ks. The authors first extracted point-source candidates using the wavdetect algorithm in the CIAO package. They set the significance threshold at 2.5 x 10-5, implying that one false positive detection would be expected at every 4 x 104 trials. As a result, 2596 source candidates were found. The number of their source candidates is nearly the same as that found by Revnivtsev et al.(2009, A&A, 507, 1211) in the same region. To select significant point sources from the candidates, the authors examined their validity based on their photometric significance (PS) and the probability of no source (PB). The PS is defined as the background-subtracted source counts (Cnet) divided by its background counts normalized by the area. PB is the probability that the source is attributable to a background fluctuation, assuming Poisson statistics. The authors recognized a source to be valid if it satisfied both these criteria: PS >= 1.0 and PB <= 1.0 x 10-2. As a result, they obtained 2002 valid point sources. This table was created by the HEASARC in December 2014 based on CDS catalog J/ApJ/766/14 file table2.dat. This is a service provided by NASA HEASARC .
EXOSAT/ME Galactic Plane Survey
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This catalog is based on information contained in Warwick et al (1988), MNRAS, 232, 551. The distribution of 2-6 keV x-ray emission in the galactic plane in the first and fourth galactic quadrants has been measured in a series of scanning observations with the medium-energy progportional counters on EXOSAT. The results are presented as contour maps and in the form of a catalogue of 70 discrete sources. Additional references can be found under the reference parameter. Additional information can be obtained upon request from the HEASARC. This is a service provided by NASA HEASARC .