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2,001 results for “x-rays”
XMM-Newton/Canada-France Redshift Survey Fields X-Ray Sources
This table contains the X-ray source catalogs for the XMM-Newton surveys of the 3 and 14 hours Right Ascension (hereafter 3-h and 14-h, respectively) fields from the Canada-France Redshift Survey. (These fields are also known as the Groth Strip). The X-ray sources cover the 0.5-10 keV flux range from ~2 x 10<sup>-15</sup> - 10<sup>-13</sup> erg/cm<sup>2</sup>/s. The authors have used a subset of the XMM-Newton sources, which have Chandra positions, to determine the best method of obtaining optical identifications of sources with only XMM-Newton positions. They have found optical identifications for 79% of the XMM-Newton sources for which there were deep optical images. The sources without optical identifications are likely to be optically fainter and have higher redshifts than the sources with identifications. The authors have estimated 'photometric redshifts' for the identified sources, calibrating their method using ~200 galaxies in the fields with spectroscopic redshifts. They find that the redshift distribution has a strong peak at z~0.7. This table was created by the HEASARC in July 2005 based on CDS table J/MNRAS/350/785/tablea12.dat (the merged Tables A1 and A2 from the published paper). This is a service provided by NASA HEASARC .
HEAO 1 A1 X-Ray Source Catalog
The HEAO 1 A-1 X-Ray Source Catalog contains information about X-ray sources detected with the NRL Large Area Sky Survey Experiment (also referred to as the A-1 Experiment) flown aboard the HEAO-1 satellite. The catalog represents results from the first six months of data from HEAO-1, during which time a scan of the entire sky was completed. Positions and intensities for 842 sources are listed, with a limiting flux of 250 nanoJanskies (nJy) at 5 keV, or about 0.25 Uhuru flux units (UFU). The catalog is more than 90% complete at a flux level equivalent to 1.5 microJanskies (µJy) at 5 keV, for a Crab-like spectrum. The A-1 catalog has been cross-referenced with published literature. Identifications based on coincidence in position have been proposed for some of the sources for which previous work has established no firm identification. Half of the sources remained unidentified at the time of catalog publication (1984). The A3 database contains a list of 654 optical objects identified with A-1 error boxes. Minor structural changes were made to this database table and the documentation was revised by the HEASARC in July 2004. The basic content of the database table was unchanged, however. This is a service provided by NASA HEASARC .
NGC 6334 Chandra X-Ray Point Source Catalog
The full stellar population of NGC 6334, one of the most spectacular regions of massive star formation in the nearby Galaxy, has not been well sampled in past studies. The authors have analyzed a mosaic of two Chandra X-ray Observatory images of the region using sensitive data analysis methods, giving a list of 1607 faint X-ray sources with arcsecond positions and approximate line-of-sight absorption. About 95% of these are expected to be cluster members, most lower mass pre-main-sequence stars. Extrapolating to low X-ray levels, the total stellar population is estimated to be 20,000 - 30,000 pre-main-sequence stars. The X-ray sources show a complicated spatial pattern with ~10 distinct star clusters. The heavily obscured clusters are mostly associated with previously known far-infrared sources and radio H II regions. The lightly obscured clusters are mostly newly identified in the X-ray images. Dozens of likely OB stars are found, both in clusters and dispersed throughout the region, suggesting that star formation in the complex has proceeded over millions of years. A number of extraordinarily heavily absorbed X-ray sources are associated with the active regions of star formation. This table was created by the HEASARC in August 2009 based on the electronic version of table 1 from the above reference which were obtained from the AJ web site. This is a service provided by NASA HEASARC .
Chandra Deep Field-South 7-Megasecond X-Ray Source Catalog
This table contains the X-ray source catalogs for the ~7 Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2 square arcminutes. Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric extraction and significance assessment, the authors have created a main source catalog (entries with source_sample = 'M' in this HEASARC table) containing 1,008 sources that are detected in up to three X-ray bands: 0.5-7.0 keV, 0.5-2.0 keV, and 2-7 keV. A supplementary source catalog entries with source_sample = 'S' in this HEASARC table) is also provided, including 47 lower-significance sources that have bright (K<sub>s</sub> <~ 23<sup>m</sup>) near-infrared (NIR) counterparts. The authors have identified multiwavelength counterparts for 992 (98.4%) of the 1,008 main-catalog sources, and they have collected redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, the authors have identified 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous ~4 Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. The observations utilized in this survey have achieved unprecedented X-ray sensitivity with average flux limits over the central ~1 arcmin<sup>2</sup> region of ~1.9 x 10<sup>-17</sup>, 6.4 x 10<sup>-18</sup>, and 2.7 x 10<sup>-17</sup> erg cm<sup>-2</sup> s<sup>-1</sup> in the three X-ray bands, respectively. In the reference paper, the authors provide cumulative number-count measurements observing, for the first time, that normal galaxies start to dominate the X-ray source population at the faintest 0.5-2.0 keV flux levels. The highest X-ray source density reaches ~50,500 deg<sup>-2</sup>, and 47% +/- 4% of these sources are AGNs (~23,900 deg<sup>-2</sup>). The authors adopted a binomial no-source probability value, P<sub>B</sub> < 0.007 as the criterion to prune their initial candidate source list and generate a main source catalog, which includes 1,008 sources with a ~97% multiwavelength-identification rate. This adopted P<sub>B</sub> threshold will have inevitably rejected real X-ray sources. To recover some of these real sources, the authors created a supplementary source catalog that contains lower-significance X-ray sources that have bright optical/NIR counterparts; the chance of a bright optical/NIR source being associated with a spurious X-ray detection is quite small. A total of 47 candidate CDF-S sources having 0.007 <= P<sub>B</sub> < 0.1 are associated with bright, K<sub>s</sub> <= 23<sup>m</sup>, TENIS sources, where the false-match rate is only 1.7%, and these 47 sources constitute the supplementary catalog. A Galactic column density of N<sub>H,Gal</sub> = 8.8 * 10<sup>19</sup> cm<sup>-2</sup> along the line of sight to the CDF-S is assumed in this study. All quoted magnitudes are in the AB system. A cosmology with H<sub>0</sub> = 67.8 km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 0.308, and Omega<sub>Lambda</sub> = 0.692 (Planck Collaboration et al. 2016 values) is used to calculate luminosities. This HEASARC table contains the 1,008 sources from the main Chandra source catalog (these entries are identified by the HEASARC-created source_sample parameter being set to 'M' in this table) and the 47 lower-significance sources from the supplementary NIR-bright Chandra source catalog (these entries are identified by the HEASARC-created source_sample parameter being set to 'S' in this table). This table thus has 1,055 entries. This table was created by the HEASARC in March 2017 based upon electronic versions of Tables 4 and 5, the 'Main Chandra Source Catalog' and the 'Supplementary NIR-Bright Chandra Source Catalog', respectively, which were obtained from the ApJS website. 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 .
ROSAT North Ecliptic Pole Survey X-Ray Source Catalog
This table contains the ROSAT North Ecliptic Pole (NEP) Survey X-Ray Source Catalog. The sky around the NEP, at RA (J2000.0) = 18h00m00s, Declination (J2000.0) = +66d33'39", has the deepest exposure of the entire ROSAT All-Sky Survey (RASS). The NEP is an undistinguished region of moderate Galactic latitude, b = 29.8 degrees, and hence it is suitable for compiling statistical samples of both Galactic and extragalactic objects. The authors have made such a compilation in the 80.6 square degrees region surrounding the NEP. Their sample fully exploits the properties of the RASS, since the only criteria for inclusion are source position and significance, and it yields the deepest large solid angle contiguous sample of X-ray sources to date. They find 442 unique sources above a flux limit ~2 x 10<sup>-14</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> in the 0.5-2.0 keV band. In this table, the X-ray properties of these sources as determined from the RASS are presented. These include positions, fluxes, spectral information in the form of hardness ratios, and angular sizes. This table was created by the HEASARC in February 2006 based on a machine-readable version of Table 4 in the above paper which was obtained from the electronic ApJ website. This is a service provided by NASA HEASARC .
Optically Selected Radio-Intermediate and Loud Quasars X-ray Emission Catalog
This catalog contains some of the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). The authors have combined large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs and 603 RLQs. This sample is constructed independently of X-ray properties but has a high X-ray detection rate (85%); it provides broad and dense coverage of the luminosity-redshift (l-z) plane, including at high redshifts (22% of the objects have z = 2-5), and it extends to high radio-loudness R<sub>L</sub> values (33% of objects have R<sub>L</sub> = log(L<sub>r</sub>/L<sub>o</sub>) = 3 - 5), where L<sub>r</sub> and L<sub>o</sub> are the rest-frame monochromatic luminosities at 5 GHz and 2500 Angstroms, respectively). The authors measure the "excess" X-ray luminosity of RIQs and RLQs relative to radio-quiet quasars (RQQs) as a function of radio loudness and luminosity, and parametrize the X-ray luminosity of RIQs and RLQs both as a function of optical/UV luminosity and also as a joint function of optical/UV and radio luminosity. RIQs are only modestly X-ray bright relative to RQQs; it is only at high values of radio loudness (R<sub>L</sub> >~ 3.5) and radio luminosity that RLQs become strongly X-ray bright. This HEASARC table contains the primary sample from the reference paper. The authors consider three categories of quasars in this work: RQQs, RIQs, and RLQs (rather than just RQQs and RLQs), where the define RIQs to consist of objects with 1 <= R<sub>L</sub> < 2; consequently, the objects they classify as RLQs satisfy R<sub>L</sub> >= 2. The primary sample contained herein consists of 654 optically selected RIQs and RLQs with SDSS/FIRST observations and high-quality X-ray coverage from Chandra (171), XMM-Newton (202), or ROSAT (281). The primary sample is split nearly evenly between spectroscopic (312) and high-confidence photometric (342) quasars. Most (562) of the primary sample objects possess serendipitous off-axis X-ray coverage, while the remainder (92) were targeted in the observations used in this sample. The X-ray detection fraction for the primary sample is 84%; the detection fraction for those objects with Chandra/XMM-Newton/ROSAT coverage is 95%/92%/70% (typical ROSAT observations are comparatively less sensitive and have higher background). The authors adopt a standard cosmology with H<sub>0</sub> = 70 km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 0.3, and Omega<sub>Lambda</sub> = 0.7 throughout their study. This table was created by the HEASARC in October 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/726/20">CDS Catalog J/ApJ/726/20</a> file table1.dat. This is a service provided by NASA HEASARC .
NGC 2516 Cluster XMM-Newton X-Ray Point Source Catalog
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 L<sub>x</sub> (erg s<sup>-1</sup>) = 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 .
Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog
The authors have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~ 60% which rises to ~ 85% among sources with at least 10 ks of XRT exposure time. The authors construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, they find that the big blue bump contributes about ~ 0.3 dex to the quasar luminosity. The authors re-visit the alpha<sub>ox</sub> - L<sub>2500A</sub> relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. They find only a weak correlation between L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>UV</sub>. They do not find significant correlations between alpha<sub>x</sub> and alpha<sub>ox</sub>, alpha<sub>ox</sub> and alpha<sub>UV</sub>, and alpha<sub>x</sub> and log L(0.3-10 keV). The correlations between alpha<sub>UV</sub> and alpha<sub>x</sub>, alpha<sub>ox</sub> and alpha<sub>x</sub>, alpha<sub>ox</sub> and alpha<sub>UV</sub>, L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>x</sub>, and L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>ox</sub> are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state. This quasar sample was compiled in the following steps: 1. Candidate objects for the catalog were selected as any SDSS DR5 quasar that lie within 20 arcminutes of the center of the Swift FOV in any pointing from launch through 2008 June. 2. XRT data were processed to obtain X-ray count rates, spectra, and spectral parameters. 3. UVOT data were processed to obtain UV and optical photometry. 4. UVOT photometry were supplemented with measurements at other wavelengths from published catalogs. 5. Quasar SEDs were constructed. 6. Additional parameters were calculated based on the SEDs of each quasar. The raw sample is constructed by matching 3.5 years Swift pointings and the SDSS DR5 quasar catalog and contains 1034 objects. This HEASARC version of this catalog contains all 1034 objects in the "raw" catalog. To select only the 843 objects in the "final" catalog, the user should specify catalog_flag = 1 in any searches of this table. This table was created by the HEASARC in August 2012 based on an electronic version of Table 8 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
Copernicus X-Ray Observations
Copernicus was the third satellite in the OAO program. It was launched the 21 august of 1972 and operated till 1981. The main instrument was an ultraviolet telescope with a spectrometer to measure interstellar absorption lines in the spectra of stellar objects. However it carried also an X-ray experiment provided by University College of London/MSSL consisted in 4 co-aligned experiments sensitive in the 1-10 keV energy range. This database accesses the raw FITS file containing data obtained from the UCL X-ray Experiment (UCLXE) package on board Copernicus. This is a service provided by NASA HEASARC .
M 37 Chandra X-Ray Point Source Catalog
Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. The authors used the Chandra X-ray Observatory to study M 37 (NGC 2099), a 500-Myr-old open cluster that has been extensively surveyed for rotation periods (P<sub>rot</sub>). M 37 was observed almost continuously for five days, for a total of 440.5 ks, to measure stellar X-ray luminosities (L<sub>X</sub>), a proxy for coronal activity, across a wide range of masses. The cluster's membership catalog was revisited to calculate updated membership probabilities from photometric data and each star's distance to the cluster center. The result is a comprehensive sample of 1699 M 37 members: 426 with P<sub>rot</sub>, 278 with X-ray detections, and 76 with both. The authors calculate Rossby numbers, R<sub>o</sub>= P<sub>rot</sub>/tau , where tau is the convective turnover time, and ratios of the X-ray-to-bolometric luminosity, L<sub>X</sub>/L<sub>bol</sub>, to minimize mass dependencies in their characterization of the rotation-coronal activity relation at 500 Myr. They find that fast rotators, for which R<sub>o</sub> < 0.09 +/- 0.01, show saturated levels of activity, with log(L<sub>X</sub>/L<sub>bol</sub>) = -3.06 +/- 0.04. For R<sub>o</sub> >= 0.09 +/- 0.01, activity is unsaturated and follows a power law of the form R<sup>beta</sup><sub>o</sub> , where beta = -2.03 (-0.14, +0.17). This is the largest sample available for analyzing the dependence of coronal emission on rotation for a single-aged population, covering stellar masses in the range 0.4 - 1.3 solar masses, P<sub>rot</sub> in the range 0.4 - 12.8 days, and L<sub>X</sub> in the range 10<sup>28.4</sup> - 10<sup>30.5</sup> erg s<sup>-1</sup>. These results make M 37 a new benchmark open cluster for calibrating the ARAR at ages of ~ 500 Myr. The central field of M 37 was observed five separate times between 2011 November 14 20:58 and 2011 November 1915:31 UTC for a total of 440.5 ks with the Advanced CCD Imaging Spectrometer (ACIS). The four ACIS-I chips and the ACIS-S3 chip were used in Very Faint telemetry mode to improve the screening of background events and thus increase the sensitivity of ACIS to faint sources. The exposure-weighted average aimpoint of the 16.9 x 16.9 arcmin<sup>2</sup> ACIS-I field of view is RA = 05<sup>h</sup> 52<sup>m</sup> 17.86<sup>s</sup>,Dec = +32<sup>o</sup> 33' 48.23" (J2000). The pitch angle for four observations was 103 degrees; due to scheduling constraints, it was 253 degrees for the fifth. Table 1 in the reference paper provides the basic information for the 5 Chandra observations and Figure 1 in that paper shows their footprints superimposed on a 40' x 40' i' image centered on M 37 obtained by Hartman et al. (2008, ApJ, 675, 1233, hereafter HA08) with the Megacam on the MMT telescope. This HEASARC table contains all of the data from Table 3 of the reference paper, the M 37 Chandra catalog of 774 X-ray sources, and the data from Table 5, the catalog of optical objects, for those objects which have been identified as optical counterparts to the X-ray sources. It does not contain entries for those optical objects in Table 5 which lack X-ray counterparts. This online catalog was created by the HEASARC in December 2015 based on machine-readable versions of tables 3 and 5 from the paper which were obtained from the ApJ website. This is a service provided by NASA HEASARC .
NGC 2903 Central Region Chandra X-Ray Point Source Catalog
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 (kT<sub>e</sub> ~ 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 kT<sub>e</sub> ~ 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 10<sup>38</sup> 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 D<sub>25</sub> 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 <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/758/105">CDS Catalog J/ApJ/758/105</a> file table3.dat. This is a service provided by NASA HEASARC .
MER 2 MARS ALPHA PARTICLE X-RAY SPECTROMETER 2 XRAYSPEC V1.0
This archive contains Mars Exploration Rover x-ray data products from the APXS instrument and ancillary files. The APXS x-ray products archived on this volume were generated by the APXS Science Team, Max Planck Institute, for the Mars Exploration Rover Project.
NGC 404 Chandra X-Ray Point Source Catalog
This table contains a comprehensive X-ray point-source catalog of NGC 404, the closest face-on (inclination angle of 11 degrees) S0 galaxy to the Milky Way, which was obtained as part of the Chandra Local Volume Survey (CLVS) and originally published in Binder et al. (2013). A new 97-ks Chandra ACIS-S observation of NGC 404 was combined with archival observations for a total exposure of ~123 ks. This survey yields 74 highly significant X-ray point sources and is sensitive to a limiting unabsorbed luminosity of ~6 x 10<sup>35</sup> erg/s in the 0.35-8 keV band. To constrain the nature of each X-ray source, cross-correlations with multi-wavelength data were generated. The authors searched overlapping Hubble Space Telescope (HST) observations for optical counterparts to their X-ray detections, but found only two X-ray sources with candidate optical counterparts. They found 21 likely low-mass X-ray binaries (LMXBs), although this number is a lower limit due to the difficulties in separating LMXBs from background active galactic nuclei (AGN). The X-ray luminosity functions (XLFs) in both the soft and hard energy bands are presented in the 2013 reference paper. The XLFs in the soft band (0.5-2 keV) and the hard band (2-8 keV) have a limiting luminosity at the 90% completeness limit of 10<sup>35</sup> erg/s and 10<sup>36</sup> erg/s, respectively, significantly lower than previous X-ray studies of NGC 404. The authors find the XLFs to be consistent with those of other X-ray populations dominated by LMXBs. However, the number of luminous (>10<sup>37</sup> erg/s) X-ray sources per unit stellar mass in NGC 404 is lower than is observed for other galaxies. The relative lack of luminous XRBs may be due to a population of LMXBs with main-sequence companions formed during an epoch of elevated star formation ~0.5 Gyr ago. NGC 404 was observed during Chandra X-Ray Observatory Cycle 12 on 2010 October 21-22 for 97 ks using the ACIS-S array (Obs. ID 12339). The authors additionally utilized archival observations: NGC 404 was observed on 1999 December 19 (Obs. ID 870) for ~24 ks and on 2000 August 30 (Obs. ID 384) for ~2 ks, both using the ACIS-S array. The authors created images in the following energy bands (keV): 0.35-8.0, 0.35-1.0, 1.0-2.0, 2.0-8.0 with bin sizes of 1, 2, 3, and 4. The iterative source detection strategy that was used is described in Section 2.3 of Binder et al. (2012, ApJ, 758, 15). 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 or 0.35 - 8.0 keV. To be included in the final NGC 404 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. The final CLVS source catalog for NGC 404 contains 74 sources. Given the survey size of these NGC 404 observations, there are expected to be ~1.6 false sources included in this NGC 404 final source catalog. Three HST fields were used to search for optical counterparts for each of the X-ray sources. One field (labeled "DEEP") was taken as part of the Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury (ANGST, GO-10915; Dalcanton et al. 2009, ApJS, 183, 67), while the other two shallower fields (labeled "NE" and "SW") were obtained as part of GO-11986. Details of the HST data acquisition and data reduction are provided in Williams et al. (2010, ApJ, 716, 71). This table was created by the HEASARC in September 2015 primarily based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/763/128">CDS Catalog J/ApJ/763/128</a> files table3.dat, table4.dat, table5.dat, table6.dat, table10.dat, table12.dat and table13.dat (Binder et al. 2013) which contain the properties of the 74 Chandra point sources found in this study.and of their multi-wavelength counterparts. As noted above, the HEASARC has added an extra parameter b4_flux which was taken from the machine-readable version of Table 5 of Binder et al. (2015). This is a service provided by NASA HEASARC .
ROSAT Deep X-Ray Radio Blazar Survey Catalog
The authors have undertaken a survey, the Deep X-Ray Radio Blazar Survey (DXRBS), of archived, pointed ROSAT Position Sensitive Proportional Counter (PSPC) data for blazars by correlating the ROSAT WGACAT database with several publicly available radio catalogs, restricting their candidate list to serendipitous flat radio spectrum sources (Alpha<sub>r</sub> <= 0.70, where S<sub>Nu</sub> ~ Nu<sup>-Alpha<sub>r</sub></sup>). In their first paper (DXRBS-I), the authors discuss their survey methods, identification procedure, and first results. Their survey was found to be 95% efficient at finding flat-spectrum radio-loud quasars (FSRQs; 59 of their first 85 identifications) and BL Lacertae objects (22 of their first 85 identifications), a figure that is comparable to or greater than that achieved by other radio and X-ray survey techniques. The identifications presented therein showed that all previous samples of blazars (even when taken together) did not representatively survey the blazar population, missing critical regions of (L<sub>X</sub>, L<sub>R</sub>) parameter space within which large fractions of the blazar population lie. Particularly important was the identification of a large population of FSRQs (>=25% of DXRBS-I FSRQs) with ratios of X-ray to radio luminosity >= 10<sup>-6</sup> (Alpha<sub>rx</sub> <= 0.78). In addition, as a result of their greater sensitivity, the DXRBS-I already more than doubled the number of FSRQs in complete samples with 5-GHz (radio) luminosities between 10<sup>31.5</sup> and 10<sup>33.5</sup> ergs/s/Hz, and filled in the region of parameter space between X-ray-selected and radio-selected samples of BL Lac objects. The DXRBS-I was the very first sample to contain statistically significant numbers of blazars at low luminosities, approaching what should be the lower end of the FSRQ luminosity function. In DXRBS-II, the authors presented new identifications and spectra for 106 sources, including 86 radio-loud quasars, 11 BL Lacertae objects, and nine narrow-line radio galaxies. Together with the DXRBS-I objects and already-known sources, their sample now contained 298 identified objects: 234 radio-loud quasars [181 flat-spectrum quasars: FSRQ (Alpha<sub>r</sub> <= 0.50) and 53 steep-spectrum quasars: SSRQ], 36 BL Lacs and 28 narrow-line radio galaxies. Redshift information is available for 96 per cent of these. Thus, the selection technique was ~90 per cent efficient at finding radio-loud quasars and BL Lacs. Reaching 5-GHz radio fluxes of ~ 50 mJy and 0.1 - 2.0 keV X-ray fluxes of a few times 10<sup>-14</sup> erg/cm<sup>2</sup>/s, DXRBS is the faintest and largest flat-spectrum radio sample with nearly complete (~85 per cent) identification. The DXRBS-I entries in this catalog (identified by having values of the parameter dxrbs_part equal to 1) contain data for 85 identified sources meeting the authors' selection criteria. A number of sources were serendipitously observed by ROSAT on more than one occasion, and, for completeness, the WGACAT positions and values for these multiply observed sources are listed separately, resulting in 102 DXRBS-I entries in this catalog (71 sources with 1 X-ray observation, 11 sources with 2 X-ray observations, and 3 sources with 3 X-ray observations). The DXRBS-II entries in this catalog (identified by having values of the parameter dxrbs_part equal to 2) contain data for 106 identified sources meeting the authors' selection criteria. A number of sources were serendipitously observed by ROSAT on more than one occasion, and, for completeness, the WGACAT positions and values for these multiply observed sources are listed separately. In one case (1WGA J0513.8+0156') the source was detected twice by ROSAT and there are two possible optical counterparts: there are 2 entries for each X-ray observation corresponding to the different conterparts, resulting in a total of 4 entries for this source. There are 92 DXRBS-II sources with 1 X-ray observation, 11 sources with 2 X-ray observations, 2 sources with 4 X-ray observations and 1 source with 5 X-ray observations) resulting in 127 DXRBS-II entries for 106 sources in this catalog. Four of the DXRBS-I objects (1WGA J0421.5+1433, 1WGA J0528.5-5820, 1WGA J1057.6-7724 and 1WGA J1222.6+2934) were also included in DXRBS-II as higher signal-to-noise ratio (S/N) spectra were available. Thus, in the sum of the 2 DXRBS parts presented here, there are 229 entries corresponding to 191 newly discovered sources. The 109 previously identified blazars, 97 of which were listed in Table 6 of DXRBS-I, are not included in this table. This table was created by the HEASARC in March 2012 based on the merger of files table3.dat and table4.dat from the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/115/1253">CDS Catalog J/AJ/115/1253</a&g
Trifid Nebula (M 20) Chandra X-Ray Point Source Catalog
This table contains a list of the Trifid Nebula (M 20) X-Ray point sources detected by the Chandra X-ray Observatory (CXO) in an observation carried out on 2002 June 13. The Trifid Nebula, a young star-forming H II region, was observed for 16 hr by the Advanced CCD Imaging Spectrometer imaging array, ACIS-I, detector. 304 X-ray sources were detected, 30% of which are hard sources (defined as those sources having a 0.5-2.0 keV to 2.0-8.0 keV hardness ratio > -0.2) and 70% of which have near-infrared counterparts. This table was created by the HEASARC in January 2007 based on CDS table J/ApJ/607/904/table1.dat. This is a service provided by NASA HEASARC .
NGC 2024 Chandra X-Ray Point Source Catalog
The NGC 2024 Chandra X-Ray Point Source Catalog contains the results of a sensitive 76 ks Chandra observation of the young stellar cluster in NGC 2024, lying at a distance of ~415 pc in the Orion B giant molecular cloud. Previous infrared observations have shown that this remarkable cluster contains several hundred embedded young stars, most of which are still surrounded by circumstellar disks. Thus, it presents a rare opportunity to study X-ray activity in a large sample of optically invisible protostars and classical T Tauri stars (CTTSs) undergoing accretion. Chandra detected 283 X-ray sources, of which 248 were identified with counterparts at other wavelengths, mostly in the near-infrared. Astrometric registration of Chandra images against the Two Micron All Sky Survey (2MASS) resulted in positional offsets of ~0.25" near field center, yielding high confidence identifications of infrared counterparts. The Chandra detections are characterized by hard, heavily absorbed spectra and specular variability. Spectral analysis of more than 100 of the brightest X-ray sources yields a mean V-band extinction of ~10.5 magnitudes and typical plasma energies <kT> ~ 3 keV. Chandra detected all but one of a sample of 27 classical T Tauri stars (CTTSs) identified from previous near- and mid-infrared photometry, and their X-ray and bolometric luminosities are correlated. IRS 2b, which is thought to be a massive embedded late O or early B star that may be the ionizing source of NGC 2024, is detected as an X-ray source. Seven millimeter-bright cores (FIR 1-7) in NGC 2024 that may be protostellar were not detected, with the possible exception of faint emission near the unusual core FIR 4. This table was created by the HEASARC in January 2007 based on CDS table J/ApJ/598/375/table1.dat. This is a service provided by NASA HEASARC .
Orion Flanking Fields Chandra X-Ray Point Source Catalog
This table contains the results of Chandra observations of two flanking fields (FFs) in Orion outside the Orion Nebula Cluster (ONC), in the form of a catalog of 417 sources, which includes X-ray luminosity, optical and infrared photometry, and X-ray variability information. 91 variable sources were found, 33 of which have flarelike light curves, and 11 of which have a pattern of a steady increase or decrease over a 10 hour period. The optical and infrared photometry for the stars identified as X-ray sources are consistent with most of these objects being pre-main-sequence stars with ages younger than 10 Myr. The two flanking fields in Orion were observed with the Advanced CCD Imaging Spectrometer (ACIS) detector on board the Chandra X-Ray Observatory. The north Orion flanking field (NOFF) is centered at a J2000 RA and Declination of 05:35:19, -04:48:15, which is about 36' (~5 pc, at a distance of 470 pc) north of the Trapezium cluster and was observed on 2002 August 26 with a total exposure time of 48.8 ks. The south Orion flanking field (SOFF), centered at a J2000 RA and Declination of 05:35:06, -05:40:48, which is about 17' (~ 2.5pc, at a distance of 470 pc) south of the Trapezium cluster, was observed on 2002 September 6 with a total exposure time of 47.9 ks. The data analysis for these observations was performed in the same manner as described in Ramirez et al. (2004, AJ, 127, 2659) for a similar observation of a field in NGC 2264, which should be consulted for the full details. (See also the help file for the HEASARC version of the catalog from the latter reference available at /W3Browse/chandra/ngc2264cxo.html ). This table was created by the HEASARC in February 2007 based on the CDS table J/AJ/128/787, files table1.dat, table3.dat and table4.dat. It does not include the results from the spectral analysis of 44 bright X-ray sources which were presented in Table 2 of the reference paper. This is a service provided by NASA HEASARC .
NGC 4636 Chandra X-Ray Point Source Catalog
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 10<sup>37</sup> erg s<sup>-1</sup> 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 10<sup>37</sup> erg s<sup>-1</sup> 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 10<sup>37</sup> erg s<sup>-1</sup> <= L<sub>x</sub> <= 1 x 10<sup>38</sup> erg s<sup>-1</sup>. 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 .
M 81 Chandra X-Ray Point Source Catalog
This table contains the source table from an analysis of 15 Chandra ACIS observations of the nearby spiral galaxy M81 taken over the course of six weeks in 2005 May-July. Each observation reaches a sensitivity of ~10<sup>37</sup> erg s<sup>-1</sup>. With these observations and one previous deeper Chandra observation (the properties of which are described in Table 1 and Section 2 of the reference paper), the authors have compiled a master source list of 265 point sources, extracted and fitted their spectra, and differentiated basic populations of sources through their colors. They also carried out variability analyses of individual point sources and of X-ray luminosity functions (XLFs) in multiple regions of M 81 on timescales of days, months, and years. They find that, despite measuring significant variability in a considerable fraction of sources, snapshot observations provide a consistent determination of the XLF of M81. They also fit the XLFs for multiple regions of M81 and, using common parametrization, compare these luminosity functions to those of two other spiral galaxies, M31 and the Milky Way. This table contains the 265 point sources at or above the 99.9% probability level of being real according to AE's PROB_NO_SOURCE statistic (the "master" source list), and 11 additional "borderline" sources which have 99.0-99.9% probability of being real according to AE's PROB_NO_SOURCE statistic, for a total of 276 sources whose properties were described in Tables 3 and 4 of the reference paper. The 265 "master" sources have source numbers from 1 to 265 while the 11 "borderline" sources have source numbers beginning with 'B', e.g., they have source numbers 'B1' to 'B11'. Note that only coordinates are listed for 3 sources in the master source list (source numbers 234, 241 and 262) and 2 sources in the borderline source list (B8 and B9) because they were only in the field of view (on chip) of one observation (ObsID 735). Six additional sources near the center of M81 which were found using maximum likelihood image reconstruction are not included in either the master or borderline source lists contained herein but their positions are listed in table 2 of the reference paper. This table was created by the HEASARC in August 2011 based on electronic versions of Tables 3 and 4 from the reference paper which were obtained from the ApJ web site. 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 .
Chandra Serendipitous Extragalactic X-Ray Source ID (SEXSI) Optical Follow-Up
The Serendipitous Extragalactic X-ray Source Identification (SEXSI) Program is designed to expand significantly the sample of identified extragalactic hard X-ray sources at intermediate fluxes, 10<sup>-15</sup> ergs/cm<sup>2</sup>/s < 2-10 keV Flux <~ 10<sup>-13</sup> ergs/cm<sup>2</sup>/s. SEXSI, which includes sources derived from more than 2 square degrees of Chandra images, provides the largest hard X-ray-selected sample yet studied, offering an essential complement to the Chandra Deep Fields (total area of 0.2 square degrees). In Eckart et al. (2005, Paper II) R-band optical imaging of the SEXSI fields from the Palomar P60 and P200, the MDM 2.4m and 1.3m, and the Keck I telescopes is described. The authors have identified counterparts or derived flux limits for nearly 1000 hard X-ray sources. Using the optical images, they have derived accurate source positions. They have investigated correlations between optical and X-ray flux, and optical flux and X-ray hardness ratio. They have also studied the density of optical sources surrounding X-ray counterparts, as well as the properties of optically faint, hard X-ray sources. In Eckart et al. (2006, Paper III) optical spectra of 477 counterparts are presented. These spectra reach to R-band magnitudes of <~24 and have produced identifications and redshifts for 438 hard X-ray sources. Typical completeness levels in the 27 Chandra fields studied are 40-70%. The vast majority of the 2-10 keV selected sample are AGNs with redshifts between 0.1 and 3; the highest redshift source lies at z = 4.33. This table which combines data presented in Eckart et al. (2005, 2006) has links to the list of SEXSI X-ray sources (the HEASARC Browse table CHANSEXSI: see Paper I = Harrison et al. 2003, ApJ, 596, 944). This table was originally created by the HEASARC in June 2005 based on the CDS version of Table 3 from Eckart et al. (2005: CDS table J/ApJS/156/35/table3.dat). It was updated in August 2006 to include information from Table 2 of Eckart et al. (2006: the electronic version available at the electronic ApJ web site). This is a service provided by NASA HEASARC .
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.