- ID:
- ivo://CDS.VizieR/IX/22
- Title:
- Einstein extended deep survey
- Short Name:
- IX/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Einstein Deep Survey program (EDS) consists of very deep X-ray exposures in selected regions of the sky at high galactic latitude. The main purposes of the survey are to investigate the nature of the extragalactic X-ray background through direct source counts at very low flux levels and to study the nature of the very faint X-ray sources which comprise a significant fraction, if not all, of the soft X-ray background. The survey includes 9 IPC observations and 34 HRI observations, which, in general, cover the central 32'x32' regions of the IPC fields. In total, 178 IPC sources and 202 HRI sources were detected above thresholds set to allow ~1 false source per observation. Data from all IPC energy bands and all HRI detect cells are included. The data are largely the result of standard Einstein Rev. 1 HRI and Rev. 1B IPC reprocessing; however, minor corrections to IPC count rates, fluxes, and flux significances have been made to account for different column densities toward various fields and small systematic errors in the IPC analysis of count rates and significances for long exposures. For further details please refer to the paper referenced above. The HRI field parameters have been determined from standard processing and from other information contained in the HRI .SDF file. For information on HRI sources, see the table "hsrc.dat"; for information on individual IPC fields, see the table "ifield.dat".
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- ID:
- ivo://CDS.VizieR/IX/18
- Title:
- EINSTEIN extended source survey (EXSS)
- Short Name:
- IX/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains sources from data collected by the IPC on board the EINSTEIN Observatory. This survey is designed to find extended sources and diffuse emission rather than point sources. In addition, the source detection algorithm is substantially improved over that used by EMSS. Sources were searched using circular apertures up to 6.1arcmin. The catalog contains 1326 extended source candidates at high galactic latitude (|b| > 20{deg}).
- ID:
- ivo://CDS.VizieR/J/ApJ/511/65
- Title:
- Einstein images of galaxy clusters
- Short Name:
- J/ApJ/511/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the X-ray characteristics of a sample of 368 clusters of galaxies with redshifts less than 0.2 observed with the Einstein Imaging Proportional Counter. For each cluster, we measure the 0.5-4.5keV counting rate and compute the 0.5-4.5keV source luminosity, as well as the bolometric luminosity within fixed metric radii. We detect 85% of Abell clusters with z<0.1, demonstrating that the large majority of these optically selected clusters are not the results of chance superpositions. For 163 clusters, we measure their X-ray surface brightness profiles and determine their core radii. For {~}230 clusters, we then use either our measured core radii and values, or mean values derived for this sample, to measure central gas densities and gas masses. We use estimated or measured cluster gas temperatures, along with the derived gas-density profiles, to estimate total cluster masses, under the assumptions that the gas is isothermal and in hydrostatic equilibrium.
- ID:
- ivo://CDS.VizieR/J/AJ/115/2587
- Title:
- Einstein IPC database ultrasoft survey
- Short Name:
- J/AJ/115/2587
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a survey of the entire Einstein IPC database (a total of 5934 sources) to select objects with strong components of ultrasoft X-ray emission (i.e., emission below 0.5keV). The selection criteria are based on ratios of counts within three broad energy bands (i.e., X-ray "colors"). A total of 516 objects have been selected, with 202 (39%) having been identified through correlations with other databases. Of the currently identified objects, 45% are active galactic nuclei, 28% are stellar objects, 6% are "normal" galaxies and galaxy clusters, and the remaining 21% are "nonstellar" Galactic objects such as cataclysmic variables, pulsars, and white dwarfs. We present a discussion of the survey selection procedure, the list of selected sources, and discussions of interesting objects from the aforementioned groups. We discuss the remarkable success of our rather "low resolution" method of estimating spectral shape and present plans for follow-up studies of the as yet unidentified sources.
- ID:
- ivo://CDS.VizieR/IX/25
- Title:
- Einstein Observatory IPC Parameters
- Short Name:
- IX/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog gives information for each Einstein Observatory Imaging Proportional Counter (IPC) observation used in the Einstein Observatory Source Catalog (EOSCAT). It also contains information relating to individual "HUTS" (HEAO Universal Time), time segments of data which were summed to create IPC Sequence numbers. Each HUT is designated by its initial major frame
- ID:
- ivo://CDS.VizieR/J/ApJS/97/141
- Title:
- Einstein sample multiparametric analysis. I.
- Short Name:
- J/ApJS/97/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted bivariate and multivariate statistical analysis of data measuring the luminosity and interstellar medium of the Einstein sample of early-type galaxies (presented by Fabbiano, Kim & Trinchiere =1992ApJS...80..531F).
- ID:
- ivo://CDS.VizieR/J/ApJ/325/798
- Title:
- Einstein survey of stars in the Hyades
- Short Name:
- J/ApJ/325/798
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper reports the results of an extensive X-ray study of the Hyades region and improves on previous studies by using refined X-ray source detection algorithms and the complete set of Einstein Observatory IPC exposures covering the Hyades cluster region (a total of 63 1 x 1 deg images). Maximum likelihood integral X-ray luminosity functions were computed for the Hyades stars for given color index (B-V) ranges. The present results agree substantially with a previous survey about the ubiquity of the stellar activity in the Hyades cluster, especially among solar-type stars. The result of Stern et al. (1981ApJ...249..647S) that stellar X-ray emission is dependent on stellar age is confirmed.
- ID:
- ivo://CDS.VizieR/J/ApJ/437/361
- Title:
- Einstein survey of the Orion nebula region
- Short Name:
- J/ApJ/437/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed archival Einstein Observatory images of a roughly 4.5 square degree region centered on the Orion Nebula. In all, 245 distinct X-ray sources have been detected in six High Resolution Imager (HRI) and 17 Imaging Proportional Counter (IPC) observations. An optical database of over 2700 stars has been assembled to search for candidate counterparts to the X-ray sources. Roughly half the X-ray sources are identified with a single Orion Nebula cluster member. The 10 main-sequence O6-B5 cluster stars detected in Orion have X-ray activity levels comparable to field O and B stars. X-ray emission has also been detected in the direction of four main-sequence late-B and early-A type stars. Since the mechanisms producing X-rays in late-type coronae and early-type winds cannot operate in the late-B and early-A type atmospheres, we argue that the observed X-rays, with L_X_~3x10^30^ergs/s, are probably produced in the coronae of unseen late-type binary companions. Over 100 X-ray sources have been associated with late-type pre-main sequence stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/111/163
- Title:
- Einstein X-ray survey of galaxies. I.
- Short Name:
- J/ApJS/111/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a complete Einstein imaging proportional counter X-ray survey of optically-selected galaxies from the Shapley-Ames Catalog (Cat. <VII/112>), the Uppsala General Catalog (Cat. <VII/26>) and the European Southern Observatory Catalog (Cat. <VII/115>). Well-defined optical criteria are used to select the galaxies, and X-ray fluxes are measured at the optically-defined positions. The result is a comprehensive list of X-ray detection and upper limit measurements for 1018 galaxies. Of these, 827 have either independent distance estimates or radial velocities. Associated optical, redshift, and distance data have been assembled for these galaxies, and their distances come from a combination of directly predicted distances and those predicted from the Faber-Burstein Great Attractor/Virgocentric infall model. The accuracy of the X-ray fluxes has been checked in three different ways; all are consistent with the derived X-ray fluxes being of <=0.1 dex accuracy. In particular, there is agreement with previously published X-ray fluxes for galaxies in common with a 1991 study by Roberts et al. (1991ApJS...75..751R) and a 1992 study by Fabbiano et al. (1992ApJS...80..531F).The data presented here will be used in further studies to characterize the X-ray output of galaxies of various morphological types and thus to enable the determination of the major sources contributing to the X-ray emission from galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/456/881
- Title:
- EIS: infrared deep public survey
- Short Name:
- J/A+A/456/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of the series presenting the final results obtained by the ESO Imaging Survey (EIS) project. It presents new J and Ks data obtained from observations conducted at the ESO 3.5m New Technology Telescope (NTT) using the SOFI camera. These data were taken as part of the Deep Public Survey (DPS) carried out by the ESO Imaging Survey program, significantly extending the earlier optical/infrared EIS-DEEP survey presented in a previous paper of this series. The DPS-IR survey comprises two observing strategies: shallow Ks observations providing nearly full coverage of pointings with complementary multi-band (in general UBVRI) optical data obtained using ESO's wide-field imager (WFI) and deeper J and Ks observations of the central parts of these fields. Currently, the DPS-IR survey provides a coverage of roughly 2.1 square degrees (~300 SOFI pointings) in Ks with 0.63 square degrees to fainter magnitudes and also covered in J, over three independent regions of the sky. The goal of the present paper is to briefly describe the observations, the data reduction procedures, and to present the final survey products which include fully calibrated pixel-maps and catalogs extracted from them. The astrometric solution with an estimated accuracy of <0.15" is based on the USNO catalog and limited only by the accuracy of the reference catalog. The final stacked images presented here number 89 and 272, in J and Ks, respectively, the latter reflecting the larger surveyed area. The J and Ks images were taken with a median seeing of 0.7" and 0.8". The images reach a median 5 sigma limiting magnitude of J_AB~23.06 as measured within an aperture of 2", while the corresponding limiting magnitude in Ks_AB is ~21.41 and ~22.16mag for the shallow and deep strategies. Although some spatial variation due to varying observing conditions is observed, overall the observed limiting magnitudes are consistent with those originally proposed. The quality of the data has been assessed by comparing the measured magnitude of sources at the bright end directly with those reported by the 2MASS survey and at the faint end by comparing the counts of galaxies and stars with those of other surveys to comparable depth and to model predictions. The final science-grade catalogs together with the astrometrically and photometrically calibrated co-added images are available at CDS.