- ID:
- ivo://CDS.VizieR/J/ApJS/149/29
- Title:
- ROSAT North Ecliptic Pole Survey
- Short Name:
- J/ApJS/149/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The X-ray data around the North Ecliptic Pole (NEP) of the ROSAT All Sky Survey have been used to construct a contiguous area survey consisting of a sample of 445 individual X-ray sources above a flux of ~2x10^-14^erg/cm^2^/s in the 0.5-2.0keV energy band. The NEP survey is centered at RA=18:00 (2000) DE=+66:33 and covers a region of 80.7deg^2^ at a moderate Galactic latitude of b=29.8{deg}. Hence, the NEP survey is as deep and covers a comparable solid angle to the ROSAT serendipitous surveys but is also contiguous. We have identified 99.6% of the sources and determined redshifts for the extragalactic objects. In this paper we present the optical identifications of the NEP catalog of X-ray sources including basic X-ray data and properties of the sources. We also describe with some detail the optical identification procedure. The classification of the optical counterparts to the NEP sources is very similar to that of previous surveys, in particular the Einstein Extended Medium Sensitivity Survey (EMSS). The main constituents of the catalog are active galactic nuclei (AGNs) (~49%), either type 1 or type 2 according to the broadness of their permitted emission lines. Stellar counterparts are the second most common identification class (~34%). Clusters and groups of galaxies comprise 14%, and BL Lacertae objects 2%. One non-AGN galaxy and one planetary nebula have also been found. The NEP catalog of X-ray sources is a homogeneous sample of astronomical objects featuring complete optical identification.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/595/1206
- Title:
- ROSAT view of Hipparcos F stars
- Short Name:
- J/ApJ/595/1206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For a set of 11900 F stars that have uvby photometry and are in the Hipparcos (Cat. <I/239>) catalog, we have found 1980 X-ray counterparts (~17%) in the ROSAT All-Sky Surveys (RASS, Cat. <IX/10> and <IX/29>). In this paper we analyze X-ray properties of these ROSAT F stars and compare that sample with the entire set of our F stars.
- ID:
- ivo://CDS.VizieR/J/A+A/390/173
- Title:
- RR Lyrae GCVS and TYC2 identifiers
- Short Name:
- J/A+A/390/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Tycho-2 catalogue (<I/259>) provides astrometric and photometric data for the 2.5 million brightest stars in the sky. Therefore it can provide much larger samples than the Hipparcos samples used to date in statistical studies. The object of this paper is the cross-identification of Tycho-2 sources and known variable stars of RR Lyrae type. The Tycho-2 data of cross-identified sources are added into the ASTRID specialized database. The present selection almost doubles the size of the sample of RR Lyrae stars with available proper motions.
- ID:
- ivo://CDS.VizieR/J/A+A/402/801
- Title:
- Runaway carbon stars of Blanco & McCarthy field 37
- Short Name:
- J/A+A/402/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have been recently faced with the problem of cross-identifying stars recorded in historical catalogues with those extracted from recent fully digitized surveys (such as DENIS and 2MASS). Positions mentioned in the old catalogues are frequently of poor precision, but are generally accompanied by finding charts where the interesting objects are flagged. Those finding charts are sometimes our only link with the accumulated knowledge of past literature. While checking the identification of some of these objects in several catalogues, we had the surprise to discover a number of discrepancies in recent works.The main reason for these discrepancies was generally the blind application of the smallest difference in position as the criterion to identify sources from one historical catalogue to those in more recent surveys. In this paper we give examples of such mis-identifications, and show how we were able to find and correct them.We present modern procedures to discover and solve cross-identification problems, such as loading digitized images of the sky through the Aladin service at CDS, and overlaying entries from historical catalogues and modern surveys. We conclude that the use of good finding charts still remains the ultimate (though time-consuming) tool to ascertain cross-identifications in difficult cases.
305. SAGE AGB candidates
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1195
- Title:
- SAGE AGB candidates
- Short Name:
- J/ApJ/723/1195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine variability information from the MAssive Compact Halo Objects survey of the Large Magellanic Cloud with infrared photometry from the Spitzer Space Telescope Surveying the Agents of a Galaxy's Evolution survey to create a data set of ~30000 variable red sources. We photometrically classify these sources as being on the first ascent of the red giant branch, or as being in one of three stages along the asymptotic giant branch (AGB): oxygen-rich, carbon-rich, or highly reddened with indeterminate chemistry ("extreme" AGB candidates). We present linear period-luminosity (P-L) relationships for these sources using eight separate infrared bands (J, H, Ks, 3.6, 4.5, 5.8, 8.0, and 24um) as proxies for the luminosity. We find that the wavelength dependence of the slope of the P-L relationship is different for different photometrically determined classes of AGB stars. Stars photometrically classified as O-rich show the least variation of slope with wavelength, while dust enshrouded extreme AGB stars show a pronounced trend toward steeper slopes with increasing wavelength. We find that O-rich AGB stars pulsating in the fundamental mode obey a period-magnitude relation with a slope of -3.41+/-0.04 when magnitude is measured in the 3.6um band, in contrast to C-rich AGB stars, which obey a relation of slope -3.77+/-0.05.
- ID:
- ivo://CDS.VizieR/I/222
- Title:
- San Fernando AC Zone Data Reduced to ACRS
- Short Name:
- I/222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the San Fernando Zone, whose plates are centered between declinations -3 and -9 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of over 225,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
- ID:
- ivo://CDS.VizieR/IV/12
- Title:
- SAO-HD-GC-DM Cross Index (ADC 1983)
- Short Name:
- IV/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is an updated, corrected, and extended version of a table of correspondences originally prepared by Morin (1973). The individual data corrections, additions, and changes included in the new version number 11398, with 8600 data records having at least one change. In addition to the correction of all errors found since preparation of the original catalog, most of which resulted from misidentifications and omissions of components in multiple-star systems and missing Durchmusterung numbers (the common identifier) in the SAO Catalog, component identifications from the Index Catalogue of Visual Double Stars (IDS) have been appended to all multiple SAO stars having the same DM numbers, and lowercase identifications for supplemental (footnoted) BD stars have been added. Stars deleted (duplicate entries) in the SAO Catalog have been appended with a "D" and their data removed, although the records have been kept (with SAO number only) in order not to change the number of SAO stars. The data include SAO number, HD number, HD multiplicity code, GC number, DM identification code (BD, CD, CP), and number. There are fewer objects than records because of the deleted entries appended with a "D" as described above (35 stars deleted).
- ID:
- ivo://CDS.VizieR/J/ApJ/765/62
- Title:
- SDSS-DR7 optical spectra analysis of radio galaxies
- Short Name:
- J/ApJ/765/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a large sample of narrow-line radio galaxies (NLRGs) with extended radio structures. Using 1.4GHz radio luminosities L_1.4_, narrow optical emission line luminosities L_[OIII]_ and L_Halpha_, as well as black hole masses M_BH_ derived from stellar velocity dispersions measured from the optical spectra obtained with the Sloan Digital Sky Survey, we find that (1) NLRGs cover about four decades of the Eddington ratio, {lambda}{equiv}L_bol_/L_Edd_{prop.to}L_line_/M_BH_; (2) L_1.4_/M_BH_ strongly correlates with {lambda}; and (3) radio loudness, R=L_1.4_/L_Line_, strongly anti-correlates with {lambda}. A very broad range of the Eddington ratio indicates that the parent population of NLRGs includes both radio-loud quasars (RLQs) and broad-line radio galaxies (BLRGs). The correlations they obey and their high jet production efficiencies favor a jet production model which involves the so-called magnetically choked accretion scenario. In this model, production of the jet is dominated by the Blandford-Znajek mechanism, and the magnetic fields in the vicinity of the central black hole are confined by the ram pressure of the accretion flow. Since large net magnetic flux accumulated in central regions of the accretion flow required by the model can take place only via geometrically thick accretion, we speculate that the massive, "cold" accretion events associated with luminous emission-line active galactic nucleus can be accompanied by an efficient jet production only if preceded by a hot, very sub-Eddington accretion phase.
- ID:
- ivo://CDS.VizieR/J/AJ/135/10
- Title:
- SDSS-DR4/RASS source matching
- Short Name:
- J/AJ/135/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may be weak, or obscured by dust. To aid in the understanding of weakly accreting black holes in the local universe, a large sample of galaxies with X-ray detections is needed. We cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because of the high SDSS source density and large RASS positional errors, the cross-matched catalog is highly contaminated by random associations. We investigate the overlap of these surveys and provide a statistical test of the validity of RASS-SDSS galaxy cross-matches.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A97
- Title:
- SDSS-IV/SPIDERS X-ray PS Spectroscopic Catalog
- Short Name:
- J/A+A/636/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We look to provide a detailed description of the SPectroscopic IDentification of ERosita Sources (SPIDERS) survey, an SDSS-IV programme aimed at obtaining spectroscopic classification and redshift measurements for complete samples of sufficiently bright X-ray sources. We describe the SPIDERS X-ray Point Source Spectroscopic Catalogue, considering its store of 11092 observed spectra drawn from a parent sample of 14759 ROSAT and XMM sources over an area of 5129deg^2^ covered in SDSS-IV by the eBOSS survey. This programme represents the largest systematic spectroscopic observation of an X-ray selected sample. A total of 10970 (98.9%) of the observed objects are classified and 10849 (97.8%) have secure redshifts. The majority of the spectra (10070 objects) are active galactic nuclei (AGN), 522 are cluster galaxies, and 294 are stars. The observed AGN redshift distribution is in good agreement with simulations based on empirical models for AGN activation and duty cycle. Forming composite spectra of type 1 AGN as a function of the mass and accretion rate of their black holes reveals systematic differences in the H-beta emission line profiles. This study paves the way for systematic spectroscopic observations of sources that are potentially to be discovered in the upcoming eROSITA survey over a large section of the sky.
