- ID:
- ivo://nasa.heasarc/exogps
- Title:
- EXOSAT/ME Galactic Plane Survey
- Short Name:
- EXOSAT/Plane
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
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- ID:
- ivo://nasa.heasarc/exms
- Title:
- EXOSAT ME Slew Catalog
- Short Name:
- EXOSAT/Slew
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is the first online version of the EXMS catalog. It contains information on the 1210 sources detected by EXOSAT during slew manoevers between 1983 and 1986. Each detection was obtained by searching for excesses above the background level in the light curve, fitted with the expected triangular profile due to the source passing from one side of the collimator to the other. These light curves are available for inspection from the xray account at ESTEC/ESA (telnet :://xray@exosat.estec.esa.nl). The detection time, raw 1-8 keV count rate and position (based on the centroid of the uncertainty region) are given for all 1210 entries. 80% of entries have proposed single identifications, obtained by cross-correlation of the uncertainty region against other catalogs. For these sources, the count rates are also supplied after correction for collimator efficiency, normalised to counts/sec/half, where "half" refers to one half of the ME detector array. This ensures consistency with the entries in the ME database. Coordinates of the proposed counterpart are also given, together with object type. The remaining sources consist of cases where more than one plausible candidate lay within the uncertainty region or where no candidate could be found. For these cases, only raw count rates are supplied. This database is a modified copy of the exms databases available from ESTEC/ESA. It was re-built by the HEASARC in July 1999. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/me
- Title:
- EXOSAT ME Spectra and Lightcurves
- Short Name:
- ME
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The EXOSAT Medium Energy experiment (ME) was an array of eight proportional counters with a total geometric area of 1600 cm<sup>2</sup>. The field of view was square and 0.75 degrees x 0.75 degrees FWHM on each side. Each proportional counter consisted of an argon chamber on top of a xenon chamber separated by a 1.5 mm beryllium window. The fractional energy resolution, dE/E, was 21(E/6 keV)<sup>-0.5</sup> percent FWHM for the argon chambers. The output from each chamber was pulse height analyzed into 128 channels with the argon chambers sensitive from 1-20 keV and the xenon from 5-50 keV. To optimize the background subtraction, each half of the detector array was alternately offset to a source-free region of sky to monitor the particle background. Only results from the argon detectors are included in the EXOSAT ME database. The high count rates given by the ME required OBC (on board computer) programs to compress the data prior to their being telemetered. Depending on the objective of the observation the OBC programs traded time resolution against spectral information. Depending on the telemetry load, and the OBC programs running for the other two experiments, two or three ME programs could be run simultaneously. The spectral orientated programs gave spectra plus intensity profiles. The timing programs gave purely intensity profile data with in some cases selectable channels. The highest time resolution possible for a single selectable energy band was 0.2 ms. The products available within this database has been created using the data sampled by the spectral orientated OBC programs. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/exolog
- Title:
- EXOSAT Observation Log
- Short Name:
- EXOLOG
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains the EXOSAT observation log. This is a complete list of all EXOSAT observations, observing modes, and principal investigators. The log can be used to find out which targets were observed by EXOSAT, who observed them, and the current state of the data analysis. The HEASARC revised this database table in August, 2005, in an effort to modernize its parameter names and add Galactic coordinates. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/tgs
- Title:
- EXOSAT TGS L and R Orders
- Short Name:
- TGS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Spectra obtained using the EXOSAT transmission grating spectrometer, TGS. There are two databases TGS and TGS2 as follows: <pre> * TGS - the grating spectra averaged over the positive and negative orders * TGS2 - the postive and negative orders kept separate </pre> TGS provides a better overview of the spectrum, and is quicker to use with a spectral fitting program. This is the default that most users will want to use. Once a user has become more expert and wants to see, for example, if a subtle feature is present in both halves of the grating spectra, the user can access TGS2. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/tgs2
- Title:
- EXOSAT TGS Spectra and Lightcurves
- Short Name:
- TGS2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Spectra obtained using the EXOSAT transmission grating spectrometer, TGS. There are two databases TGS and TGS2 as follows: <pre> * TGS - the grating spectra averaged over the positive and negative orders * TGS2 - the postive and negative orders kept separate </pre> TGS provides a better overview of the spectrum, and is quicker to use with a spectral fitting program. This is the default that most users will want to use. Once a user has become more expert and want to see, for example, if a subtle feature is present in both halves of the grating spectra, the user can access TGS2. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ecdfsnew
- Title:
- Extended Chandra Deep Field South 250-ks Improved Point Source Catalog
- Short Name:
- ECDFSNEW
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the improved point-source catalog for the 250-ks Extended Chandra Deep Field-South (E-CDF-S) Survey, implementing a number of recent improvements in Chandra source-cataloguing methodology. For the E-CDF-S, the main catalog (entries from which are indicated with parameter values of source_sample = "Main" in this HEASARC representation) contains 1003 X-ray sources detected with wavdetect at a false-positive probability threshold of 10<sup>-5</sup> that also satisfy a binomial-probability source-selection criterion of P < 0.002. Such an approach maximizes the number of reliable sources detected: a total of 275 main-catalog sources are new compared to the Lehmer et al. (2005, ApJS, 161, 21) E-CDF-S main catalog. The authors also provide an E-CDF-S supplementary catalog that consists of 56 sources (entries from which are indicated with parameter values of source_sample = "Supp" in this HEASARC representation) detected at the same wavdetect threshold and having P of 0.002-0.1 and K<sub>s</sub> <= 22.3 mag counterparts. For all 1059 E-CDF-S sources, including the 318 newly detected ones (these being generally fainter and more obscured), the authors determine X-ray source positions utilizing centroid and matched-filter techniques; they also provide multi-wavelength identifications, apparent magnitudes of counterparts, spectroscopic and/or photometric redshifts, basic source classifications, and estimates of observed active galactic nucleus and galaxy source densities around respective field centers. Simulations show that the E-CDF-S main catalog is highly reliable and reasonably complete. Background and sensitivity analyses indicate that the on-axis mean flux limits reached represent a factor of ~1.5-2.0 improvement over the previous E-CDF-S limit. The 250-ks E-CDF-S is composed of four distinct and contiguous ~ 250-ks Chandra pointings that flank the CDF-S proper, consisting of a total of nine separate observations taken between 2004 February 29 and November 20 (see Lehmer et al., 2005, ApJS, 161, 21 for more details). This table was created by the HEASARC in August 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/224/15">CDS Catalog J/ApJS/224/15</a> files table9.dat (the main source catalog) and table12.dat (the supplementary source catalog). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ecdfsoid2
- Title:
- Extended Chandra Deep Field-South Optical and Near-IR Counterparts
- Short Name:
- ECDFSOID2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of a program to acquire high-quality optical spectra of X-ray sources detected in the Extended-Chandra Deep Field-South (E-CDF-S) and its central 2 Ms area. New spectroscopic redshifts, up to z = 4, are measured for 283 counterparts to Chandra sources with deep exposures (t ~ 2-9 hr per pointing) using multi-slit facilities on both VLT (VIMOS) and Keck (DEIMOS), thus bringing the total number of spectroscopically identified X-ray sources to over 500 in this survey field. Since their new spectroscopic identifications are mainly associated with X-ray sources in the shallower 250 ks coverage, the authors provide a comprehensive catalog of X-ray sources detected in the E-CDF-S including the optical and near-infrared counterparts, determined by a likelihood routine, and redshifts (both spectroscopic and photometric), that incorporate published spectroscopic catalogs, thus resulting in a final sample with a high fraction (80%) of X-ray sources having secure identifications. The authors demonstrate the remarkable coverage of the luminosity-redshift plane now accessible from their data while emphasizing the detection of active galactic nuclei (AGNs) that contribute to the faint end of the luminosity function (L<sub>0.5-8keV</sub> ~ 10<sup>43</sup> - 10<sup>44</sup> erg s<sup>-1</sup>) at 1.5 <~ z <~ 3, including those with and without broad emission lines. This redshift catalog includes 17 type-2 QSOs at 1 <~ z <~ 3.5 that significantly increases (doubles) such samples. Based on thei deepest (9 hr) VLT/VIMOS observation, the authors identify "elusive" optically faint galaxies (R<sub>mag</sub> ~ 25) at z ~ 2 - 3 based upon the detection of interstellar absorption lines (e.g., O II+Si IV, C II], C IV); in their paper, they highlight one such case, an absorption-line galaxy at z = 3.208 having no obvious signs of an AGN in its optical spectrum. In addition, they determine accurate distances to eight galaxy groups with extended X-ray emission detected both by Chandra and XMM-Newton. This online catalog was created by the HEASARC in November 2010 based on a machine-readable version of Table 4 from the paper which was obtained from the ApJ website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ecdfsoid
- Title:
- Extended Chandra Deep Field-South Survey Optical Identifications Catalog
- Short Name:
- ECDFSOID
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the first results of the authors' optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South (ECDFS). A total of 339 sources (listed herein) were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. The authors have measured redshifts for 186 X-ray sources, including archival data and a literature search. They find that the active galactic nucleus (AGN) host galaxies have on average redder rest-frame optical colors than nonactive galaxies, and that they live mostly in the "green valley." The dependence of the fraction of AGNs that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN spatial density is compared with the expectations from existing luminosity functions. These AGNs show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGNs, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity. This table was created by the HEASARC in April 2009 based on the electronic version of Table 2 from the Treister et al. (2009) paper obtained from the ApJ web site, except for the source positions which were taken from Virani et al. (2006). The full table from the latter paper is also available in Browse (the ECDFSCXO table). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ecdfscxo
- Title:
- Extended Chandra Deep Field-South X-Ray Point Source Catalog
- Short Name:
- ECDFSCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Extended Chandra Deep Field-South (ECDFS) survey consists of four Chandra X-Ray Observatory (CXO) ACIS-I pointings and covers ~1100 arcmin<sup>2</sup> (~0.3 deg<sup>2</sup>) centered on the original CDF-S field to a depth of approximately 228 ks. This is the largest Chandra survey ever conducted at such depth, and only one XMM-Newton survey reaches a lower flux limit in the hard 2.0-8.0 keV band. The authors detect 651 unique sources: 587 using a conservative source-detection threshold (identified by source_type = 'P' for primary source) and 64 (identified by source_type = 'S' for secondary source) using a lower source-detection threshold. These are combined in this HEASARC representation but were presented as two separate catalogs (Table 4 contained the primary sources, and Table 5 the secondary sources) in the original reference paper. Of the 651 total sources, 561 are detected in the full 0.5-8.0 keV band, 529 in the soft 0.5-2.0 keV band, and 335 in the hard 2.0-8.0 keV band. For point sources near the aim point, the limiting fluxes are approximately 1.7 x 10<sup>-16</sup> and 3.9 x 10<sup>-16</sup> ergs/cm<sup>2</sup>/s in the 0.5-2.0 and 2.0-8.0 keV bands, respectively. In their paper, the authors present the differential and cumulative flux distributions, which are in good agreement with the number counts from previous deep X-ray surveys and with the predictions from an active galactic nucleus (AGN) population synthesis model that can explain the X-ray background. In general, fainter sources have harder X-ray spectra, consistent with the hypothesis that these sources are mainly obscured AGNs. All nine observations of the ECDFS survey field were conducted with the Advanced CCD Imaging Spectrometer (ACIS) on board Chandra as part of the approved guest observer program in Cycle 5. Notice that Lehmer et al. (2005, ApJS, 161, 21) conducted a somewhat different analysis on these same data and obtained similar, but not identical results, e.g., Lehmer et al. found 809 total X-ray sources compared to 651 in the present table. This table was created by the HEASARC in April 2009 based on the electronic versions of Tables 4 and 5 from the paper which were obtained from the CDS (their catalog J/AJ/131/2373 files table4.dat and table5.dat). This is a service provided by NASA HEASARC .
