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3001. Redshift from UBRI photometry method
ID:
ivo://CDS.VizieR/J/A+A/363/517
Title:
Redshift from UBRI photometry method
Short Name:
J/A+A/363/517
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new method is developed for estimating photometric redshifts, using realistic template Spectral Energy Distributions (SEDs), extending over four decades in wavelength (i.e. from 0.05{mu}m to 1mm). The template SEDs are constructed for four different spectral types of galaxies (elliptical, spiral, irregular and starburst), satisfying the following characteristics: a) they are normalised to produce the observed colours of galaxies at z~0; b) incorporate the chemo-photometric spectral evolution of galaxies of different types, in agreement with the observations; c) allow treatment of dust contribution and its evolution with redshift, consistent with the spectral evolution models; d) include absorption and re-emission of radiation by dust and hence, realistic estimates of the far-infrared radiation; e) include correction for inter-galactic absorption by Lyman continuum and Lyman forest. Using these template SEDs, the photometric redshifts are estimated to an accuracy of {Delta}z=0.11. The simultaneous and self-consistent modelling of both the photometric and chemical evolution of galaxies and the effect of dust, makes this technique particularly useful for high redshift galaxies. The effects on the estimated photometric redshifts, due to assumptions in the evolutionary population synthesis models, are investigated and discussed. Also, the degeneracy in the predicted photometric redshifts and spectral types are examined, using a simulated galaxy catalogue.
3002. Redshift reliability flags (VVDS data)
ID:
ivo://CDS.VizieR/J/A+A/611/A53
Title:
Redshift reliability flags (VVDS data)
Short Name:
J/A+A/611/A53
Date:
21 Oct 2021
Publisher:
CDS
Description:
Future large-scale surveys, as the ESA Euclid mission, will produce a large set of galaxy redshifts (>=10^6) that will require fully automated data-processing pipelines to analyze the data, extract crucial information and ensure that all requirements are met. A fundamental element in these pipelines is to associate to each galaxy redshift measurement a quality, or reliability, estimate. In this work, we introduce a new approach to automate the spectroscopic redshift reliability assessment based on machine learning (ML) and characteristics of the redshift probability density function. We propose to rephrase the spectroscopic redshift estimation into a Bayesian framework, in order to incorporate all sources of information and uncertainties related to the redshift estimation process and produce a redshift posterior probability density function (PDF). To automate the assessment of a reliability flag, we exploit key features in the redshift posterior PDF and machine learning algorithms.
3003. Redshifts and morphology in A3667
ID:
ivo://CDS.VizieR/J/A+A/479/1
Title:
Redshifts and morphology in A3667
Short Name:
J/A+A/479/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
The galaxy cluster A3667 was observed using the Two-degree Field (2dF) multifibre spectroscopic system on the Anglo-Australian Telescope in a program designed to examine the velocity structure in the region. Specifically, we sought evidence from the optical data for the putative cluster merger believed to be responsible for the observed radio and X-ray emission. We present 184 new redshifts in the region, of which 143 correspond to member galaxies of A3667. We find the cluster velocity distribution to be well modelled by a single Gaussian in agreement with previous results. In addition, new redshift-selected isodensity plots significantly reduce the prominence of the previously reported subgroup to the north-west of the main cluster. Instead, we find the galaxy distribution to be elongated and well mixed, with a high velocity dispersion and no significant evidence for substructure. These results are consistent with the axis of the proposed merger being close to the plane of the sky.
3004. Redshifts behind the Southern Milky Way
ID:
ivo://CDS.VizieR/J/A+A/415/9
Title:
Redshifts behind the Southern Milky Way
Short Name:
J/A+A/415/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of our efforts to unveil extragalactic large-scale structures behind the southern Milky Way, we here present redshifts for 764 galaxies in the Hydra/Antlia, Crux and Great Attractor region (266{deg}<=l<=338{deg}, |b|<=10{deg}), obtained with the Meudon-ESO Fibre Object Spectrograph (MEFOS) at the 3.6-m telescope of ESO. The observations are part of a redshift survey of partially obscured galaxies recorded in the course of a deep optical galaxy search behind the southern Milky Way (Kraan-Korteweg 2000, Cat. <J/A+AS/141/123>; Woudt & Kraan-Korteweg 2001, Cat. <J/A+A/380/441>). A total of 947 galaxies have been observed, a small percentage of the spectra (N=109, 11.5%) were contaminated by foreground stars, and 74 galaxies (7.8%) were too faint to allow a reliable redshift determination. With MEFOS we obtained spectra down to the faintest galaxies of our optical galaxy survey, and hence probe large-scale structures out to larger distances (v<=30000km/s) than our other redshift follow-ups using the 1.9-m telescope at the South African Astronomical Observatory (Kraan-Korteweg et al., 1995, Cat. <J/A+A/297/617>; Fairall et al., 1998, Cat. <J/A+AS/127/463>; Woudt et al., 1999, Cat. <J/A+A/352/39>) and the 64-m Parkes radio telescope (Kraan-Korteweg et al., 2002, Cat. <J/A+A/391/887>). The most distinct large-scale structures revealed in the southern Zone of Avoidance are discussed in context to known structures adjacent to the Milky Way.
3005. Redshifts in equatorial strip
ID:
ivo://CDS.VizieR/J/AJ/105/1637
Title:
Redshifts in equatorial strip
Short Name:
J/AJ/105/1637
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 865 redshifts of galaxies located in the equatorial strip -17.5 deg <= Dec. <= -2.5 deg in the right ascension range 20 h <= R.A. <= 5 h. Redshifts have been obtained for the complete sample of all 833 galaxies in the Morphological Catalog of Galaxies with magnitudes brighter than m = 14.5 (corresponding approximately to m(Zwicky) = 15.0). This sample also includes three galaxies from other sources with more reliable magnitudes, satisfying this limit, and 29 fainter galaxies, usually companions of the galaxies in the magnitude limited sample. Our maps of a very large volume of nearby space demonstrate a variety of coherent large scale structures which include large voids, 20-50 h^-1^ Mpc in diameter and large walls at least 70 h^-1^ Mpc across.
3006. Redshifts in LCDCS 0504
ID:
ivo://CDS.VizieR/J/A+A/566/A149
Title:
Redshifts in LCDCS 0504
Short Name:
J/A+A/566/A149
Date:
21 Oct 2021
Publisher:
CDS
Description:
Constraints on the mass distribution in high-redshift clusters of galaxies are currently not very strong. We aim to constrain the mass profile, M(r), and dynamical status of the z~0.8 LCDCS 0504 cluster of galaxies that is characterized by prominent giant gravitational arcs near its center. Our analysis is based on deep X-ray, optical, and infrared imaging as well as optical spectroscopy, collected with various instruments, which we complemented with archival data. We modeled the mass distribution of the cluster with three different mass density profiles, whose parameters were constrained by the strong lensing features of the inner cluster region, by the X-ray emission from the intracluster medium, and by the kinematics of 71 cluster members.
3007. Redshifts in nine galaxy cluster fields
ID:
ivo://CDS.VizieR/J/ApJ/797/106
Title:
Redshifts in nine galaxy cluster fields
Short Name:
J/ApJ/797/106
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use dense redshift surveys of nine galaxy clusters at z~0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70%-89%) and uniform completeness.
3008. Redshifts in Subaru/XMM Deep Field
ID:
ivo://CDS.VizieR/J/MNRAS/381/1369
Title:
Redshifts in Subaru/XMM Deep Field
Short Name:
J/MNRAS/381/1369
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present multiobject spectroscopy of galaxies in the immediate (Mpc-scale) environments of four low-power (L_1.4GHz_~<10^25^W/Hz) radio galaxies at z~0.5, selected from the Subaru/XMM-Newton Deep Field. We use the spectra to calculate velocity dispersions and central redshifts of the groups the radio galaxies inhabit, and combined with XMM-Newton (0.3-10keV) X-ray observations investigate the L_X_-{sigma}_v_ and T_X_-{sigma}_v_ scaling relationships. All the radio galaxies reside in moderately rich groups - intermediate environments between poor groups and rich clusters, with remarkably similar X-ray properties.
3009. Redshifts in supercluster SCL 2243-0935
ID:
ivo://CDS.VizieR/J/A+A/532/A57
Title:
Redshifts in supercluster SCL 2243-0935
Short Name:
J/A+A/532/A57
Date:
21 Oct 2021
Publisher:
CDS
Description:
In archival 2.2m MPG-ESO/WFI data we discovered several mass peaks through weak gravitational lensing, forming a possible supercluster at redshift 0.45. Through wide-field imaging and spectroscopy we aim to identify the supercluster centre, confirm individual member clusters, and detect possible connecting filaments. Through multi-colour imaging with CFHT/Megaprime and INT/WFC we identify a population of early-type galaxies and use it to trace the supercluster network. EMMI/NTT multi-object spectroscopy is used to verify the initial shear-selected cluster candidates. We use weak gravitational lensing to obtain mass estimates for the supercluster centre and the filaments.
3010. Redshifts in the field of A383
ID:
ivo://CDS.VizieR/J/ApJ/783/52
Title:
Redshifts in the field of A383
Short Name:
J/ApJ/783/52
Date:
21 Oct 2021
Publisher:
CDS
Description:
Abell 383 is a famous rich cluster (z=0.1887) imaged extensively as a basis for intensive strong- and weak-lensing studies. Nonetheless, there are few spectroscopic observations. We enable dynamical analyses by measuring 2360 new redshifts for galaxies with r_Petro_{<=}20.5 and within 50' of the Brightest Cluster Galaxy (BCG; R.A._2000_=42.014125{deg},decl._2000_=-03.529228{deg}). We apply the caustic technique to identify 275 cluster members within 7h^-1^Mpc of the hierarchical cluster center. The BCG lies within -11+/-110km/s and 21+/-56 h^-1^kpc of the hierarchical cluster center; the velocity dispersion profile of the BCG appears to be an extension of the velocity dispersion profile based on cluster members. The distribution of cluster members on the sky corresponds impressively with the weak-lensing contours of Okabe et al. especially when the impact of foreground and background structure is included. The values of R_200_=1.22+/-0.01h^-1^Mpc and M_200_=(5.07+/-0.09)x10^14^h^-1^M_{sun}_ obtained by application of the caustic technique agree well with recent completely independent lensing measures. The caustic estimate extends direct measurement of the cluster mass profile to a radius of ~5h^-1^Mpc.