- ID:
- ivo://CDS.VizieR/J/AJ/135/1311
- Title:
- Environments of moderate redshift radio galaxies
- Short Name:
- J/AJ/135/1311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the local universe, high-power radio galaxies live in lower-density environments than low-luminosity radio galaxies. If this trend continued to higher redshifts, powerful radio galaxies would serve as efficient probes of moderate redshift groups and poor clusters. Photometric studies of radio galaxies at 0.3<~z<~0.5 suggest that the radio luminosity-environment correlation disappears at moderate redshifts, though this could be the result of foreground/background contamination affecting the photometric measures of environment. We have obtained multi-object spectroscopy in the fields of 14 lower luminosity (L_1.4GHz_<4x10^24^W/Hz) and higher luminosity (L_1.4GHz_>1.2x10^25^W/Hz) radio galaxies at z~0.3 to spectroscopically investigate the link between the environment and the radio luminosity of radio galaxies at moderate redshifts. Our results support the photometric analyses; there does not appear to be a correlation between the luminosity of a radio galaxy and its environment at moderate redshifts. Hence, radio galaxies are not efficient signposts for group environments at moderate redshifts.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/751/102
- Title:
- Equivalent widths of 9 RGB in Carina dSph
- Short Name:
- J/ApJ/751/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detailed abundances of 23 chemical elements in nine bright red giant branch stars in the Carina dwarf spheroidal galaxy are presented based on high-resolution spectra gathered at the Very Large Telescope (VLT) and Magellan telescopes. A spherical model atmospheres analysis is applied using standard methods (local thermodynamic equilibrium and plane-parallel radiative transfer) to spectra ranging from 380 to 680nm. Stellar parameters are found to be consistent between photometric and spectroscopic analyses, both at moderate and high resolution. The stars in this analysis range in metallicity from -2.9<[Fe/H]<-1.3, and adopting the ages determined by Lemasle et al. (Cat. J/A+A/538/A100), we are able to examine the chemical evolution of Carina's old and intermediate-aged populations.
- ID:
- ivo://CDS.VizieR/J/A+A/421/59
- Title:
- Equivalent widths of VMF73 and VMF74 galaxies
- Short Name:
- J/A+A/421/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic analysis of two galaxy clusters out to ~4Mpc at z~0.2. The two clusters VMF73 and VMF74 identified by Vikhlinin et al. (1998, Cat. <J/ApJ/502/558>) were observed with MOSCA at the Calar Alto 3.5m telescope. Both clusters lie in the ROSAT PSPC field R285 and were selected from the X-ray Dark Cluster Survey (Gilbank et al., 2004MNRAS.348..551G) that provides optical V- and I-band data. VMF73 and VMF74 are located at respective redshifts of z=0.25 and z=0.18 with velocity dispersions of 671km/s and 442km/s, respectively. The spectroscopic observations reach out to ~2.5 virial radii. Line strength measurements of the emission lines H_alpha and [OII]3727 are used to assess the star formation activity of cluster galaxies which show radial and density dependences. The mean and median of both line strength distributions as well as the fraction of star forming galaxies increase with increasing clustercentric distance and decreasing local galaxy density. Except for two galaxies with strong H_alpha and [OII] emission, all of the cluster galaxies are normal star forming or passive galaxies. Our results are consistent with other studies that show the truncation in star formation occurs far from the cluster centre.
- ID:
- ivo://CDS.VizieR/J/A+A/451/881
- Title:
- ESIS BVR catalog, ELAIS-S1
- Short Name:
- J/A+A/451/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ESO-Spitzer extragalactic Imaging Survey (ESIS) is the optical follow up of the Spitzer Wide-Area InfraRed Extragalactic (SWIRE) survey in the ELAIS-S1 area. The multiwavelength study of galaxy emission is the key to understand the interplay of the various components of galaxies and to trace their role in cosmic evolution. ESIS provides optical identification and colors of Spitzer IR galaxies and builds the bases for photometric redshift estimates. This paper presents B, V, R Wide Field Imager observations of the first 1.5 square degree of the ESIS survey. Data reduction includes astrometric calibration, illumination and color corrections. Synthetic sources are simulated in scientific and super-sky-flat images, with the purpose of estimating completeness and photometric accuracy for the survey. Number counts and color distributions are compared to literature observational and theoretical data, including non-evolutionary, PLE, evolutionary and semi-analytic Lambda-CDM galaxy models, as well as Milky Way stellar predictions. Object coordinates are defined with an accuracy as good as ~0.15" rms with respect to GSC 2.2; flux uncertainties are ~2, 10, 20% at mag. 20, 23, 24 respectively (Vega); we reach 95% completeness at B, V~25 and R~24.5. ESIS galaxy number counts are in good agreement with previous works and are best reproduced by evolutionary and hierarchical Lambda-CDM scenarios.
- ID:
- ivo://CDS.VizieR/J/A+A/444/365
- Title:
- ESO Distant Cluster Survey, EDisCS
- Short Name:
- J/A+A/444/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the ESO Distant Cluster Survey (EDisCS) a survey of 20 distant galaxy clusters with redshifts ranging from 0.4 to 0.8. Candidate clusters were chosen from among the brightest objects identified in the Las Campanas Distant Cluster Survey (LCDCS), half with estimated redshift z_est_~0.5 and half with z_est_~0.8. They were confirmed by identifying red sequences in moderately deep two colour data from VLT/FORS2. For confirmed candidates we have assembled deep three-band optical photometry using VLT/FORS2, deep near-infrared photometry in one or two bands using NTT/SOFI, deep optical spectroscopy using VLT/FORS2, wide field imaging in two or three bands using the ESO Wide Field Imager, and HST/ACS mosaic images for 10 of the most distant clusters. This first paper presents our sample and the VLT photometry we have obtained. We present images, colour magnitude diagrams and richness estimates for our clusters, as well as giving redshifts and positions for the brightest cluster members. Subsequent papers will present our infrared photometry, spectroscopy, HST and wide-field imaging, as well as a wealth of further analysis and science results. Our reduced data become publicly available as these papers are accepted.
236. ESO 362-G18 datacube
- ID:
- ivo://CDS.VizieR/J/A+A/614/A94
- Title:
- ESO 362-G18 datacube
- Short Name:
- J/A+A/614/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two-dimensional stellar and gaseous kinematics of the inner 0.7x1.2kpc^2^ of the Seyfert 1.5 galaxy ESO 362-G18, derived from optical (4092-7338{AA}) spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of 170 pc and spectral resolution of 36km/s. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [OIII] emission shows a fan-shaped extension of ~10" to the SE. We detect the [OIII] doublet, [NII] and H{alpha} emission lines throughout our FOV. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of ~137{deg} and is centred approximately on the continuum peak. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122{deg} to 139{deg}, projected velocity amplitudes of the order of 100km/s, and a mean velocity dispersion of 100km/s. A double-Gaussian fit to the [OIII]{lambda}5007 and H{alpha} lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight (LOS) velocities 100-250km/s higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4x10^-2^M_{sun}_/yr in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2x10^-2^M_{sun}_/yr. The total ionized gas mass within 84pc of the nucleus is 3.3x10^5^M_{sun}_; infall velocities of ~34km/s in this gas would be required to feed both the outflow and SMBH accretion.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/2112
- Title:
- Estimating gas masses from HI and CO data
- Short Name:
- J/MNRAS/432/2112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a method to estimate the total gas column density, dust-to-gas and dust-to-metal ratios of distant galaxies from rest-frame optical spectra. The technique exploits the sensitivity of certain optical lines to changes in depletion of metals on to dust grains and uses photoionization models to constrain these physical ratios along with the metallicity and dust column density. We compare our gas column density estimates with HI and CO gas mass estimates in nearby galaxies to show that we recover their total gas mass surface density to within a factor of 2 up to a total surface gas mass density of ~75M{sun}/pc^2^. Our technique is independent of the conversion factor of CO to H_2_ and we show that a metallicity-dependent X_CO_ is required to achieve good agreement between our measurements and that provided by CO and HI. However, we also show that our method cannot be reliably aperture corrected to total integrated gas mass. We calculate dust-to-gas ratios for all star-forming galaxies in the Sloan Digital Sky Survey Data Release 7 and show that the resulting dependence on metallicity agrees well with the trend inferred from modelling of the dust emission of nearby galaxies using far-IR data. We also present estimates of the variation of the dust-to-metal ratio with metallicity and show that this is poorly constrained at metallicities below 50% solar. We conclude with a study of the inventory of gas in the central regions, defined both in terms of a fixed physical radius and as a fixed fraction of the half-light radius, of ~70000 star-forming galaxies from the Sloan Digital Sky Survey. We show that their central gas content and gas depletion time are not accurately predicted by a single parameter, but in agreement with recent studies we find that a combination of the stellar mass and some measure of central concentration provides a good predictor of gas content in galaxies. We also identify a population of galaxies with low surface densities of stars and very long gas depletion times.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/74
- Title:
- EW measurements of 6 Segue 1 red giants
- Short Name:
- J/ApJ/786/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Magellan/MIKE and Keck/HIRES high-resolution spectra of six red giant stars in the dwarf galaxy Segue 1. Including one additional Segue 1 star observed by Norris et al. (2010ApJ...722L.104N), high-resolution spectra have now been obtained for every red giant in Segue 1. Remarkably, three of these seven stars have metallicities below [Fe/H]=-3.5, suggesting that Segue 1 is the least chemically evolved galaxy known. We confirm previous medium-resolution analyses demonstrating that Segue 1 stars span a metallicity range of more than 2 dex, from [Fe/H]=-1.4 to [Fe/H]=-3.8. All of the Segue 1 stars are {alpha}-enhanced, with [{alpha}/Fe]~0.5. High {alpha}-element abundances are typical for metal-poor stars, but in every previously studied galaxy [{alpha}/Fe] declines for more metal-rich stars, which is typically interpreted as iron enrichment from supernova Ia. The absence of this signature in Segue 1 indicates that it was enriched exclusively by massive stars. Other light element abundance ratios in Segue 1, including carbon enhancement in the three most metal-poor stars, closely resemble those of metal-poor halo stars. Finally, we classify the most metal-rich star as a CH star given its large overabundances of carbon and s-process elements. The other six stars show remarkably low neutron-capture element abundances of [Sr/H]<-4.9 and [Ba/H]<-4.2, which are comparable to the lowest levels ever detected in halo stars. This suggests minimal neutron-capture enrichment, perhaps limited to a single r-process or weak s-process synthesizing event. Altogether, the chemical abundances of Segue 1 indicate no substantial chemical evolution, supporting the idea that it may be a surviving first galaxy that experienced only one burst of star formation.
- ID:
- ivo://CDS.VizieR/J/AJ/131/2859
- Title:
- Extragalactic First Look Survey: 24{mu}m data
- Short Name:
- J/AJ/131/2859
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the reduction of the 24{mu}m data obtained during the first cosmological survey performed by the Spitzer Space Telescope. Images of a region of sky at moderately high Galactic latitude (l=88.3{deg}, b=+34.9{deg}) were obtained on 2003 December 9-11. The survey consists of a shallow observation of 2.5x2{deg}^2^ centered at 17:18 +59:30 (main survey) and a deeper observation of 1{deg}x0.5{deg} centered at 17:17 +59:45 (verification survey). Issues with the reduction of the 24{mu}m MIPS data are discussed and solutions to attenuate instrumental effects are proposed and applied to the data. Approximately 17000 sources are extracted with a signal-to-noise ratio (S/N) greater than 5. The photometry of the point sources is evaluated through point-spread function (PSF) fitting using an empirical PSF derived from the data. Aperture corrections and the absolute calibration have been checked using stars in the field. Astrometric and photometric errors depend on the S/N of the source varying between 0.35"-1" and 5%-15%, respectively, for sources detected at 20-5{sigma}. The fluxes of the 123 extended sources have been estimated through aperture photometry. The extended sources cover less than 0.3% of the total area of the survey. Based on simulations, the main and verification surveys are 50% complete at 0.3 and 0.15mJy, respectively. Counterparts have been searched for in optical and radio catalogs.