- ID:
- ivo://CDS.VizieR/J/ApJS/243/21
- Title:
- A complete sample of broad-line AGN from SDSS-DR7
- Short Name:
- J/ApJS/243/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new, complete sample of 14584 broad-line active galactic nuclei (AGNs) at z<0.35 is presented, which are uncovered homogeneously from the complete database of galaxies and quasars observed spectroscopically in the Sloan Digital Sky Survey Seventh Data Release. The stellar continuum is properly removed for each spectrum with significant host absorption line features, and careful analyses of the emission line spectra, particularly in the H{alpha} and H{beta} wavebands, are carried out. The broad Balmer emission line, particularly H{alpha}, is used to indicate the presence of an AGN. The broad H{alpha} lines have luminosities in a range of 10^38.5^-10^44.3^erg/s, and line widths (FWHMs) of 500-34000km/s. The virial black hole masses, estimated from the broad-line measurements, span a range of 10^5.1^-10^10.3^M_{sun}_, and the Eddington ratios vary from -3.3 to 1.3 in logarithmic scale. Other quantities such as multiwavelength photometric properties and flags denoting peculiar line profiles are also included in this catalog. We describe the construction of this catalog and briefly discuss its properties. The catalog is publicly available online. This homogeneously selected AGN catalog, along with the accurately measured spectral parameters, provides the most updated, largest AGN sample data, which will enable further comprehensive investigations of the properties of the AGN population in the low-redshift universe.
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- ID:
- ivo://CDS.VizieR/J/ApJ/742/48
- Title:
- Blanco survey of the lens BCS J2352-5452
- Short Name:
- J/ApJ/742/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z=0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z=0.3838. The lens (BCS J2352-5452) was discovered while examining i- and z-band images being acquired in 2006 October during a BCS observing run. Follow-up spectroscopic observations with the Gemini Multi-Object Spectrograph instrument on the Gemini-South 8m telescope confirmed the lensing nature of this system. Using weak-plus-strong lensing, velocity dispersion, cluster richness N_200_, and fitting to a Navarro-Frenk-White (NFW) cluster mass density profile, we have made three independent estimates of the mass M_200_ which are all very consistent with each other. The combination of the results from the three methods gives M_200_=(5.1+/-1.3)x10^14^M_{sun}_, which is fully consistent with the individual measurements. The final NFW concentration c_200_ from the combined fit is c_200_=5.4^+1.4^_-1.1_. We have compared our measurements of M_200_ and c_200_ with predictions for (1) clusters from {Lambda}CDM simulations, (2) lensing-selected clusters from simulations, and (3) a real sample of cluster lenses.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/268
- Title:
- Bright QSOs in Southern Hemisphere (QUBRICS)
- Short Name:
- J/ApJ/887/268
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of absorptions along the lines of sight to bright high-z QSOs is an invaluable cosmological tool that provides a wealth of information on the inter-/circum-galactic medium, dark matter, primordial elements, reionization, fundamental constants, and general relativity. Unfortunately, the number of bright (i<~18) QSOs at z>~2 in the southern hemisphere is much lower than that in the north, due to the lack of wide multiwavelength surveys at decl. {delta}<0{deg}, hampering the effectiveness of observations from southern observatories. In this work we present a new method based on Canonical Correlation Analysis to identify such objects, taking advantage of a number of available databases: Skymapper, Gaia DR2, WISE, and 2MASS. Our QSO candidate sample lists 1476 sources with i<18 over 12400deg^2^ in the southern hemisphere. With a preliminary campaign we observed spectroscopically 69 of them, confirming 54 new bright QSOs at z>2.5, corresponding to a success rate of our method of ~80%. Furthermore, we estimate a completeness of ~90% of our sample at completion of our observation campaign. The new QSOs confirmed by this first and the forthcoming campaigns (QUBRICS survey) will be the targets of subsequent studies using higher resolution spectrographs, like ESPRESSO, UVES, and (in the long term) ELT/HIRES.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/11
- Title:
- Candidate Ly{alpha} emitting galaxies at z~3.8
- Short Name:
- J/ApJ/823/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the field containing the z=3.786 protocluster PC 217.96+32.3. We confirm that it is one of the largest known and most overdense high-redshift structures. Such structures are rare even in the largest cosmological simulations. We used the Mayall/MOSAIC1.1 imaging camera to image a 1.2x0.6{deg} area (~150x75 comoving Mpc) surrounding the protocluster's core and discovered 165 candidate Ly{alpha} emitting galaxies (LAEs) and 788 candidate Lyman Break galaxies (LBGs). There are at least two overdense regions traced by the LAEs, the largest of which shows an areal overdensity in its core (i.e., within a radius of 2.5 comoving Mpc) of 14+/-7 relative to the average LAE spatial density (\bar{rho}) in the imaged field. Further, \bar{rho} is twice that derived by other field LAE surveys. Spectroscopy with Keck/DEIMOS yielded redshifts for 164 galaxies (79 LAEs and 85 LBGs); 65 lie at a redshift of 3.785+/-0.010. The velocity dispersion of galaxies near the core is {sigma}=350+/-40km/s, a value robust to selection effects. The overdensities are likely to collapse into systems with present-day masses of >10^15^M_{sun}_ and >6x10^14^M_{sun}_. The low velocity dispersion may suggest a dynamically young protocluster. We find a weak trend between narrow-band (Ly{alpha}) luminosity and environmental density: the Ly{alpha} luminosity is enhanced on average by 1.35x within the protocluster core. There is no evidence that the Ly{alpha} equivalent width depends on environment. These suggest that star formation and/or active galactic nucleus (AGN) activity is enhanced in the higher-density regions of the structure. PC 217.96+32.3 is a Coma cluster analog, witnessed in the process of formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/7
- Title:
- Census of the Local Universe survey. I. CLU-Halpha
- Short Name:
- J/ApJ/880/7
- Date:
- 03 Nov 2021 07:51:08
- Publisher:
- CDS
- Description:
- We present the Census of the Local Universe (CLU) narrowband survey to search for emission-line (H{alpha}) galaxies. CLU-H{alpha} has imaged ~3{pi} of the sky (26470deg^2^) with four narrowband filters that probe a distance out to 200Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6deg^2^) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an H{alpha} flux limit of 10^-14^erg/s/cm^2^ at 90% completeness, and recovers 83% (67%) of the H{alpha} flux from cataloged galaxies in our search volume at the {Sigma}=2.5 ({Sigma}=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for {Sigma}=2.5 ({Sigma}=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional ~300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identify a known planetary nebula. These objects show that the CLU-H{alpha} survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-H{alpha} galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-H{alpha} galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/33
- Title:
- CLASH-VLT: the FF cluster MACS J0416.1-2403
- Short Name:
- J/ApJS/224/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VIMOS-Very Large Telescope (VLT) spectroscopy of the Frontier Fields (FF) cluster MACS J0416.1-2403 (z=0.397). Taken as part of the CLASH-VLT survey, the large spectroscopic campaign provided more than 4000 reliable redshifts over ~600arcmin^2^, including ~800 cluster member galaxies. The unprecedented sample of cluster members at this redshift allows us to perform a highly detailed dynamical and structural analysis of the cluster out to ~2.2r_200_ (~4Mpc). Our analysis of substructures reveals a complex system composed of a main massive cluster (M_200_~0.9x10^15^M_{sun}_ and {sigma}_V,r200_~1000km/s) presenting two major features: (i) a bimodal velocity distribution, showing two central peaks separated by {Delta}V_rf_~1100km/s with comparable galaxy content and velocity dispersion, and (ii) a projected elongation of the main substructures along the NE-SW direction, with a prominent sub-clump ~600kpc SW of the center and an isolated BCG approximately halfway between the center and the SW clump. We also detect a low-mass structure at z~0.390, ~10' south of the cluster center, projected at ~3Mpc, with a relative line-of-sight velocity of {Delta}V_rf_~-1700km/s. The cluster mass profile that we obtain through our dynamical analysis deviates significantly from the "universal" NFW, being best fit by a Softened Isothermal Sphere model instead. The mass profile measured from the galaxy dynamics is found to be in relatively good agreement with those obtained from strong and weak lensing, as well as with that from the X-rays, despite the clearly unrelaxed nature of the cluster. Our results reveal an overall complex dynamical state of this massive cluster and support the hypothesis that the two main subclusters are being observed in a pre-collisional phase, in agreement with recent findings from radio and deep X-ray data. In this article, we also release the entire redshift catalog of 4386 sources in the field of this cluster, which includes 60 identified Chandra X-ray sources and 105 JVLA radio sources.
- ID:
- ivo://CDS.VizieR/J/AJ/116/560
- Title:
- Cl J0023+0423 and Cl J1604+4304 spectroscopy
- Short Name:
- J/AJ/116/560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive photometric and spectroscopic study of two high-redshift clusters of galaxies based on data obtained from the Keck 10m telescopes and the Hubble Space Telescope. The clusters Cl 0023+0423 (z=0.84) and Cl 1604+4304 (z=0.90) are part of a multiwavelength program of Oke, Postman & Lubin (1998AJ....116..549O, Paper I) to study nine candidate clusters at z>~0.6. Based on these observations, we study in detail both the field and cluster populations. From the confirmed cluster members, we find that Cl 0023+0423 actually consists of two components separated by ~2900km/s. A kinematic analysis indicates that the two components are a poor cluster with ~3x10^14^M_{sun}_ and a less massive group with ~10^13^M_{sun}_. Cl 1604+4304 is a centrally concentrated, rich cluster at z=0.8967 with a velocity dispersion of 1226km/s and a mass of ~3x10^15^M_{sun}_.
- 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/J/ApJ/871/258
- Title:
- ELQS in SDSS. III. The full ELQS quasar catalog
- Short Name:
- J/ApJ/871/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have designed the Extremely Luminous Quasar Survey (ELQS) to provide a highly complete census of unobscured UV-bright quasars during the cosmic noon, z=2.8-5.0. Here we report the discovery of 70 new quasars in the ELQS South Galactic Cap (ELQS-S) quasar sample, doubling the number of known extremely luminous quasars in 4237.3deg^2^ of the Sloan Digital Sky Survey footprint. These observations conclude the ELQS and we present the properties of the full ELQS quasar catalog, containing 407 quasars over 11838.5deg^2^. Our novel ELQS quasar selection strategy resulted in unprecedented completeness at the bright end and allowed us to discover 109 new quasars in total. This marks an increase of ~36% (109/298) in the known population at these redshifts and magnitudes, while we further are able to retain a selection efficiency of ~80%. On the basis of 166 quasars from the full ELQS quasar catalog, which adhere to the uniform criteria of the Two Micron All Sky Survey point source catalog, we measure the bright-end quasar luminosity function (QLF) and extend it one magnitude brighter than previous studies. Assuming a single power law with exponential density evolution for the functional form of the QLF, we retrieve the best-fit parameters from a maximum likelihood analysis. We find a steep bright-end slope of {beta}~-4.1, and we can constrain the bright-end slope to {beta}<=-3.4 with 99% confidence. The density is well modeled by the exponential redshift evolution, resulting in a moderate decrease with redshift ({gamma}~-0.4).
- ID:
- ivo://CDS.VizieR/J/ApJS/256/9
- Title:
- Euclid preparation. XIV. C3R2 survey DR3
- Short Name:
- J/ApJS/256/9
- Date:
- 18 Jan 2022 14:01:22
- Publisher:
- CDS
- Description:
- The Complete Calibration of the Color-Redshift Relation (C3R2) survey is obtaining spectroscopic redshifts in order to map the relation between galaxy color and redshift to a depth of i~24.5 (AB). The primary goal is to enable sufficiently accurate photometric redshifts for Stage IV dark energy projects, particularly Euclid and the Nancy Grace Roman Space Telescope (Roman), which are designed to constrain cosmological parameters through weak lensing. We present 676 new high-confidence spectroscopic redshifts obtained by the C3R2 survey in the 2017B-2019B semesters using the DEIMOS, LRIS, and MOSFIRE multiobject spectrographs on the Keck telescopes. Combined with the 4454 redshifts previously published by this project, the C3R2 survey has now obtained and published 5130 high-quality galaxy spectra and redshifts. If we restrict consideration to only the 0.2<z_p_<2.6 range of interest for the Euclid cosmological goals, then with the current data release, C3R2 has increased the spectroscopic redshift coverage of the Euclid color space from 51% (as reported by Masters+ 2017, J/ApJ/841/111) to the current 91%. Once completed and combined with extensive data collected by other spectroscopic surveys, C3R2 should provide the spectroscopic calibration set needed to enable photometric redshifts to meet the cosmology requirements for Euclid, and make significant headway toward solving the problem for Roman.