- ID:
- ivo://CDS.VizieR/J/AJ/115/1253
- Title:
- Deep X-Ray Radio Blazar Survey (DXRBS). I.
- Short Name:
- J/AJ/115/1253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have undertaken a survey, the Deep X-Ray Radio Blazar Survey (DXRBS), of archived, pointed ROSAT Position Sensitive Proportional Counter data for blazars by correlating the ROSAT WGACAT database with several publicly available radio catalogs, restricting our candidate list to serendipitous flat radio spectrum sources ({alpha}_r_<=0.70, where S_{nu}_{prop}{nu}^-{alpha}_r_^). We discuss our survey methods, identification procedure, and first results. Our survey is found to be 95% efficient at finding flat-spectrum radio-loud quasars (FSRQs; 59 of our first 85 identifications) and BL Lacertae objects (22 of our 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 here show that all previous samples of blazars (even when taken together) did not representatively survey the blazar population, missing critical regions of (LX, LR) parameter space within which large fractions of the blazar population lie. Particularly important is the identification of a large population of FSRQs (>=25% of DXRBS FSRQs) with ratios of X-ray to radio luminosity >=10^-6^({alpha}_rx_<=0.78). In addition, as a result of our greater sensitivity, the DXRBS has already more than doubled the number of FSRQs in complete samples with 5GHz (radio) luminosities between 10^31.5^ and 10^33.5^ergs/s/Hz, and fills in the region of parameter space between X-ray-selected and radio-selected samples of BL Lac objects. The DXRBS is 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/323/757
- Title:
- Deep X-Ray Radio Blazar Survey (DXRBS). II.
- Short Name:
- J/MNRAS/323/757
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have searched the archived, pointed ROSAT Position Sensitive Proportional Counter data for blazars by correlating the WGACAT X-ray data base with several publicly available radio catalogues, restricting our candidate list to serendipitous X-ray sources with a flat radio spectrum ({alpha}_r_<=0.70, where S_{nu}_~{nu}^-{alpha}^). his makes up the Deep X-ray Radio Blazar Survey (DXRBS). Here we present new identifications and spectra for 106 sources, including 86 radio-loud quasars, 11 BL Lacertae objects, and nine narrow-line radio galaxies. Together with our previously published objects and already-known sources, our sample now contains 298 identified objects: 234 radio-loud quasars [181 flat-spectrum quasars: FSRQ ({alpha}_r_<=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 our selection technique is ~90 per cent efficient at finding radio-loud quasars and BL Lacs. Reaching 5-GHz radio fluxes ~50mJy and 0.1-2.0keV X-ray fluxes a few W10-14erg/cm^2^/s, DXRBS is the faintest and largest flat-spectrum radio sample with nearly complete (~85 per cent) identification.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/77
- Title:
- DEIMOS 10K spectroscopic survey in COSMOS field
- Short Name:
- J/ApJ/858/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 10718 objects in the COSMOS field, observed through multi-slit spectroscopy with the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope in the wavelength range ~5500-9800{AA}. The catalog contains 6617 objects with high-quality spectra (two or more spectral features), and 1798 objects with a single spectroscopic feature confirmed by the photometric redshift. For 2024 typically faint objects, we could not obtain reliable redshifts. The objects have been selected from a variety of input catalogs based on multi-wavelength observations in the field, and thus have a diverse selection function, which enables the study of the diversity in the galaxy population. The magnitude distribution of our objects is peaked at I_AB_~23 and K_AB_~21, with a secondary peak at K_AB_~24. We sample a broad redshift distribution in the range 0<z<6, with one peak at z~1, and another one around z~4. We have identified 13 redshift spikes at z>0.65 with chance probabilities <4x10^-4^, some of which are clearly related to protocluster structures of sizes >10Mpc. An object-to-object comparison with a multitude of other spectroscopic samples in the same field shows that our DEIMOS sample is among the best in terms of fraction of spectroscopic failures and relative redshift accuracy. We have determined the fraction of spectroscopic blends to about 0.8% in our sample. This is likely a lower limit and at any rate well below the most pessimistic expectations. Interestingly, we find evidence for strong lensing of Ly{alpha} background emitters within the slits of 12 of our target galaxies, increasing their apparent density by about a factor of 4.
- ID:
- ivo://CDS.VizieR/VII/234
- Title:
- DENIS catalog of galaxies
- Short Name:
- VII/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, extended and improved version of the provisional I-band catalog of DENIS galaxies. Galaxies not cross-identified with already known galaxies have been visually controlled using the DSS1 images and, occasionally, the coordinates were remeasured. The typical accuracy of coordinates is about 2". The typical error on I-band magnitude is about 0.2mag. The final catalog gives the most common names, the J2000 coordinates, the I-band magnitude, the diameter, the axis ratio and the position angle for about 43000 galaxies. It covers roughly 67% of the southern hemisphere. It is homogeneously sampled up to I=14.5 mag. The data are also available via the LEDA database.
- ID:
- ivo://CDS.VizieR/II/228A
- Title:
- DENIS Catalogue toward Magellanic Clouds (DCMC)
- Short Name:
- II/228A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first version of a complete near-IR point source catalogue towards the Magellanic Clouds extracted from the data obtained with the DEep Near Infraread Survey of the Southern Sky (DENIS). The catalogue covers an area of 19.87x16 square degrees centered on (05:27:20-69:00:00) for the Large Magellanic Cloud (LMC), and 14.7x10 square degrees centered on (01:02:40-73:00:00) for the Small Magellanic Cloud (SMC). It contains the sources detected in at least 2 of the 3 photometric bands I (Gunn-i centered at 0.8{mu}m), J (centered at 1.25{mu}m), and K_s_ (centered at 2.15{mu}m). The spatial resolution is 1" in I and 3" in the J and K bands, and the limiting magnitudes are I=18, J=16 and K_s_=14. 70% of the detected sources are real members of the Magellanic Clouds, and consist mainly of red giants, asymptotic giant branch stars and supergiants.
- ID:
- ivo://CDS.VizieR/J/ApJ/665/1194
- Title:
- Dense cores in the Orion A cloud survey
- Short Name:
- J/ApJ/665/1194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an H^13^CO^+^ (J=1-0) core survey in a large area of 1.5degx0.5deg, covering the whole region of the Orion A molecular cloud, using the Nobeyama 45m radio telescope with the 25 Beam Array Receiver System (BEARS). This survey is unique in that a large area (~48pc^2^) of the cloud was covered with a high spatial resolution of 21" (0.05pc) and with a deep integration (1sigma~0.1K in T*_A_), resulting in a core mass detection of 1.6M_{sun}_. The morphology of the H^13^CO^+^ (J=1-0) emission is very similar to that of the 850um continuum emission. We identified 236 dense cores from our data with the clumpfind algorithm. The cores are close to virial equilibrium, independent of whether they are thermal or turbulent.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/1560
- Title:
- Dense core survey in the Orion B cloud
- Short Name:
- J/ApJ/691/1560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an H^13^CO^+^(J=1-0 at 86.75433GHz) core survey in a large area of 1deg^2^, covering most of the dense region in the Orion B molecular cloud, using the Nobeyama 45m radio telescope with the 25-BEam Array Receiver System. We cataloged 151 dense cores using the clumpfind method. The cores have mean radius, velocity width, and mass of 0.10+/-0.02pc, 0.53+/-0.15km/s, and 8.1+/-6.4M_{sun}_, respectively, which are very similar to those in the Orion A cloud. We examined the spatial relation between our H^13^CO^+^ cores and the 850um cores observed by Johnstone and colleagues in 2001 (Cat. J/ApJ/559/307) and 2006 (Cat. J/ApJ/639/259), and found that there are two types of spatial relationships: H^13^CO^+^ cores with and without the 850um cores. Since the mean density of the 850um cores is higher than that of the H^13^CO^+^ cores, we can interpret the H^13^CO^+^ cores with 850um cores as being more centrally concentrated and hence more evolved, compared with those without.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1507
- Title:
- Detached M dwarf eclipsing binaries in WTS
- Short Name:
- J/MNRAS/426/1507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 16 detached M dwarf eclipsing binaries (MEBs) with J<16mag and provide a detailed characterization of three of them, using high-precision infrared light curves from the WFCAM Transit Survey (WTS). Such systems provide the most accurate and model-independent method for measuring the fundamental parameters of these poorly understood yet numerous stars, which currently lack sufficient observations to precisely calibrate stellar evolution models.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/77
- Title:
- Detailed analysis of cool WDs in the SDSS
- Short Name:
- J/ApJS/190/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectroscopy and near-infrared photometry of 126 cool white dwarfs (WDs) in the Sloan Digital Sky Survey (SDSS DR3). Our sample includes high proper motion targets selected using the SDSS and USNO-B astrometry and a dozen previously known ultracool WD candidates. Our optical spectroscopic observations demonstrate that a clean selection of large samples of cool WDs in the SDSS (and the SkyMapper, Pan-STARRS, and the Large Synoptic Survey Telescope data sets) is possible using a reduced proper motion diagram and a tangential velocity cut-off (depending on the proper motion accuracy) of 30km/s. Our near-infrared observations reveal eight new stars with significant absorption. We use the optical and near-infrared photometry to perform a detailed model atmosphere analysis. More than 80% of the stars in our sample are consistent with either pure hydrogen or pure helium atmospheres. However, the eight stars with significant infrared absorption and the majority of the previously known ultracool WD candidates are best explained with mixed hydrogen and helium atmosphere models. The age distribution of our sample is consistent with a Galactic disk age of 8Gyr. A few ultracool WDs may be as old as 12-13Gyr, but our models have problems matching the spectral energy distributions of these objects. There are only two halo WD candidates in our sample. However, trigonometric parallax observations are required for accurate mass and age determinations and to confirm their membership in the halo.
- ID:
- ivo://CDS.VizieR/VII/249
- Title:
- 6dF-DR2 Galaxy Survey
- Short Name:
- VII/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 6dF Galaxy Survey is measuring around 150000 redshifts and 15000 peculiar velocities from galaxies over the southern sky at |b|>10{deg}. When complete, it will be the largest survey of its kind by more than an order of magnitude. A total of 83014 sources now have their spectra, redshifts, and near-infrared and optical photometry available online and searchable through an Structured Query Language at www.wfau.roe.ac.uk/6dFGS/ .
