- ID:
- ivo://CDS.VizieR/J/ApJ/863/144
- Title:
- The ELQS in SDSS footprint. II. North Gal. Cap
- Short Name:
- J/ApJ/863/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the North Galactic Cap sample of the Extremely Luminous Quasar Survey (ELQS-N), which targets quasars with M_1450_{<}-27 at 2.8<=z<5 in an area of ~7600deg^2^ of the Sloan Digital Sky Survey (SDSS) footprint with 90{deg}<RA<270{deg}. Based on a near-infrared/infrared JKW2 color cut, the ELQS selection efficiently uses random forest methods to classify quasars and to estimate photometric redshifts; this scheme overcomes some of the difficulties of pure optical quasar selection at z~3. As a result, we retain a completeness of >70% over z~3.0-5.0 at m_i_<~17.5, limited toward fainter magnitudes by the depth of the Two Micron All Sky Survey. The presented quasar catalog consists of a total of 270 objects, of which 39 are newly identified in this work with spectroscopy obtained at the Vatican Advanced Technology Telescope and the MMT 6.5m telescope. In addition to the high completeness, which allowed us to discover new quasars in the already well-surveyed SDSS North Galactic Cap, the efficiency of our selection is relatively high at ~79%. Using 120 objects of this quasar sample we are able to extend the previously measured optical quasar luminosity function (QLF) by one magnitude toward the bright end at 2.8<=z<=4.5. A first analysis of the QLF suggests a relatively steep bright-end slope of {beta}~-4 for this sample. This result contrasts with previous results in the same redshift range, which find a much flatter slope around {beta}~-2.5, but agrees with recent measurements of the bright-end slope at lower and higher redshifts. Our results constrain the bright-end slope at z=2.8-4.5 to {beta}{<}-2.94 with a 99% confidence.
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- ID:
- ivo://CDS.VizieR/J/ApJS/243/5
- Title:
- The ELQS in the PS1 footprint (PS-ELQS)
- Short Name:
- J/ApJS/243/5
- Date:
- 08 Mar 2022 13:10:17
- Publisher:
- CDS
- Description:
- We present the results of the Extremely Luminous Quasar Survey in the 3{pi} survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint (~12000deg^2^) to a much larger area (~21486deg^2^). This spectroscopic survey targets the most luminous quasars (M_1450_<=-26.5; m_i_<=18.5) at intermediate redshifts (z>=2.8). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts (z_reg_) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at z_reg_>=2.8 from a parent sample of 74318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new z>=2.8 quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at z>=2.8, our quasar selection method has a selection efficiency of at least 77%. At lower declinations, -30<=DEC<=0, we approximately treble the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars (m_i_<=18.5, z>=2.8). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.
21613. The ENACS Catalogue. V.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/399
- Title:
- The ENACS Catalogue. V.
- Short Name:
- J/A+AS/129/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue resulting from the ESO Nearby Abell Cluster Survey (the ENACS), which contains redshifts and magnitudes for 5634 galaxies in the directions of 107 rich, nearby southern Abell cluster candidates. We describe the contents of the catalogue and discuss the results of a comparison between the ENACS catalogue and the COSMOS Galaxy Catalogue. When cross-correlating the two catalogues we find that, at least in the areas of the ENACS clusters, the completeness of the COSMOS catalogue is somewhat lower than was estimated previously for the carefully analyzed and well-calibrated part of the COSMOS catalogue known as the Edinburgh-Durham Southern Galaxy Survey (EDSGC). The galaxy positions in the COSMOS and ENACS catalogues are found to be on the same system to within about one arcsecond. For the clusters for which the photometry in the ENACS and COSMOS catalogues is based on the same survey plates, the two magnitude scales agree very well. We confirm that the photometric calibration in the EDSGC subset of the COSMOS catalogue is of higher quality than in the EDSGC complement. The ENACS galaxy samples are unbiased subsets of the COSMOS catalogue as far as the projected galaxy distribution is concerned, except in only a few cases. We summarize how the ENACS galaxy samples are subsets of the COSMOS catalogues in the ENACS apertures, with respect to magnitude. For the ENACS catalogue as a whole, we describe the apparent incompleteness at faint magnitudes and towards higher redshifts. Finally, we provide some detailed information about the ENACS catalogue that is essential for its proper statistical use and we summarize some facts that must be remembered when selecting subsets of galaxies from it. Objects:
21614. The epoch ICRF
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2633
- Title:
- The epoch ICRF
- Short Name:
- J/MNRAS/430/2633
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The epoch International Celestial Reference Frame (epoch ICRF) is proposed as a new concept in order to consider the effect of apparent proper motion of the position of a radio source due to acceleration of the spatial origin of the ICRF, the centre of mass of the Solar system. This apparent proper motion has a magnitude of approximately 5.8-microarcsec ({mu}as) per year, and for the 30-year very long baseline interferometry (VLBI) observational history these position variations will exceed 100{mu}as. We show that the dipole structure of the apparent proper motions leads to global rotation in the ICRF2 and the main term, the shift of direction of the origin of right ascension, reaches 25{mu}as per century. The 'epoch ICRF' is constructed using epoch positions at J2000.0 and apparent proper motions of radio sources, which are reported here for 295 ICRF2-defining sources.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A76
- Title:
- The ESO DIBs Large Exploration Survey
- Short Name:
- J/A+A/606/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the C^+^_60_ fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectral-type stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution (R~70000-100000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305-1042nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided.
- ID:
- ivo://CDS.VizieR/J/A+A/310/8
- Title:
- The ESO Nearby Abell Cluster Survey I.
- Short Name:
- J/A+A/310/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of the ESO Key-programme on "Structure and Dynamics of Rich Galaxy Clusters" (which we will henceforth refer to as the ESO Nearby Abell Cluster Survey - or ENACS). We discuss the sample of clusters for which data were obtained, and the observational programme of spectroscopy and photometry that we carried out. The final database contains a total of 5634 galaxies in the directions of 107 clusters from the catalogue by Abell, Corwin and Olowin 1989 (ACO hereafter) with richness R>=1 and mean redshifts z<=0.1.
- ID:
- ivo://CDS.VizieR/J/A+A/310/31
- Title:
- The ESO Nearby Abell Cluster Survey. II.
- Short Name:
- J/A+A/310/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ESO Nearby Abell Cluster Survey (the ENACS) has yielded 5634 redshifts for galaxies in the directions of 107 rich, Southern clusters selected from the ACO catalogue (Abell et al. 1989). By combining these data with another 1000 redshifts from the literature, of galaxies in 37 clusters, we construct a volume-limited sample of 128 R_ACO_>=1 clusters in a solid angle of 2.55sr centered on the South Galactic Pole, out to a redshift z=0.1. For a subset of 80 of these clusters we can calculate a reliable velocity dispersion, based on at least 10 (but very often between 30 and 150) redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/1097
- Title:
- The EVN Galactic Plane Survey - EGaPS
- Short Name:
- J/MNRAS/419/1097
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I present a catalogue of positions and correlated flux densities of 109 compact extragalactic radio sources in the Galactic plane determined from analysis of a 48 hour VLBI experiment at 22GHz with the European VLBI Network. The median position uncertainty is 9mas. The correlated flux densities of detected sources are in the range of 20 to 300mJy. In addition to target sources, nine water masers have been detected, two of them new. I derived position of masers with accuracies 30 to 200mas and determined velocities of maser components and their correlated flux densities.
- ID:
- ivo://CDS.VizieR/J/AJ/157/177
- Title:
- The evolutionary status of GK subgiants
- Short Name:
- J/AJ/157/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Snowden & Young (2005ApJS..157..126S) suggested that the reason why there are GK subgiants is because they are members of binaries, which would bring them above the main sequence in an Hertzsprung-Russell (HR) diagram. They studied a sample of 30 G0-K1 IV stars and were disappointed to find only two to be spectroscopic binaries. With more accurate radial velocities I found seven binaries in their samples of subgiants and control stars; orbital elements are given for those seven. Using Hipparcos parallaxes and SIMBAD data, I found that nearly all of the G0-K1 IV stars fall on the evolutionary tracks by Girardi et al. (2000, J/A+AS/141/371) for Population I stars with masses of 0.9-1.9 M_{sun}_ and ages of up to 10^10^ yr, which are normal parameters for nearby field stars. Therefore there is no problem regarding the existence of GK subgiants.
- ID:
- ivo://CDS.VizieR/J/ApJS/194/28
- Title:
- The evolution of cataclysmic variables
- Short Name:
- J/ApJS/194/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an attempt to reconstruct the complete evolutionary path followed by cataclysmic variables (CVs), based on the observed mass-radius relationship of their donor stars. Along the way, we update the semi-empirical CV donor sequence presented previously by one of us, present a comprehensive review of the connection between CV evolution and the secondary stars in these systems, and reexamine most of the commonly used magnetic braking (MB) recipes, finding that even conceptually similar ones can differ greatly in both magnitude and functional form.