- ID:
- ivo://CDS.VizieR/J/MNRAS/350/1485
- Title:
- 2dFGRS: Radio galaxies properties
- Short Name:
- J/MNRAS/350/1485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The clustering properties of local, S_1.4GHz_>=1mJy, radio sources are investigated for a sample of 820 objects drawn from the joint use of the Faint Images of the Radio Sky at 20cm (FIRST, <VIII/71>) and 2dF Galaxy Redshift surveys (<VII/223>, <VII/226>). To this aim, we present 271 new b_J_<=19.45mag spectroscopic counterparts of FIRST radio sources to be added to those already introduced in our previous paper.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/352/939
- Title:
- 2dFGRS Wiener reconstruction of cosmic web
- Short Name:
- J/MNRAS/352/939
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reconstruct the underlying density field of the Two-degree Field Galaxy Redshift Survey (2dFGRS, <VII/226>) for the redshift range 0.035<z<0.200 using the Wiener filtering method. The Wiener filter suppresses shot noise and accounts for selection and incompleteness effects. The method relies on prior knowledge of the 2dF power spectrum of fluctuations and the combination of matter density and bias parameters, however the results are only slightly affected by changes to these parameters. We present maps of the density field. We use a variable smoothing technique with two different effective resolutions: 5 and 10h^-1^Mpc at the median redshift of the survey. We identify all major superclusters and voids in the survey. In particular, we find two large superclusters and two large local voids. The full set of colour maps can be viewed on the World Wide Web at http://www.ast.cam.ac.uk/~pirin .
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/425
- Title:
- 2dF-SDSS Luminous Red Galaxy Survey, 2SLAQ
- Short Name:
- J/MNRAS/372/425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic survey of almost 15000 candidate intermediate-redshift luminous red galaxies (LRGs) brighter than i=19.8, observed with 2dF on the Anglo-Australian Telescope. The targets were selected photometrically from the Sloan Digital Sky Survey (SDSS) and lie along two narrow equatorial strips covering 180deg^2^. Reliable redshifts were obtained for 92 per cent of the targets and the selection is very efficient: over 90 per cent have 0.45<z<0.8. More than 80 per cent of the ~11000 red galaxies have pure absorption-line spectra consistent with a passively evolving old stellar population. The redshift, photometric and spatial distributions of the LRGs are described. The 2SLAQ data will be released publicly from mid-2006, providing a powerful resource for observational cosmology and the study of galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/1443
- Title:
- 2dF study of globular clusters in NGC 5128
- Short Name:
- J/MNRAS/386/1443
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a spectroscopic study of globular clusters (GCs) in the nearest giant elliptical NGC 5128 using the 2dF facility at the Anglo-Australian Telescope. We obtained integrated optical spectra for a total of 254 GCs, 79 of which are newly confirmed on the basis of their radial velocities and spectra. In addition, we obtained an integrated spectrum of the galaxy starlight along the southern major axis.
- ID:
- ivo://CDS.VizieR/J/MNRAS/353/601
- Title:
- 2dF survey of the Small Magellanic Cloud
- Short Name:
- J/MNRAS/353/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of new spectral types for hot, luminous stars in the Small Magellanic Cloud. The catalogue contains 4161 objects, giving an order of magnitude increase in the number of SMC stars with published spectroscopic classifications. The targets are primarily B- and A-type stars (2862 and 853 objects respectively), with 1 Wolf-Rayet, 139 O-type, and 306 FG stars, sampling the main sequence to ~mid-B. The selection and classification criteria are described, and objects of particular interest are discussed, including UV-selected targets from the Ultraviolet Imaging Telescope (UIT) experiment, Be and B[e] stars, `anomalous A supergiants', and composite-spectrum systems. We examine the incidence of Balmer-line emission, and the relationship between H-gamma equivalent width and absolute magnitude for BA stars.
- ID:
- ivo://CDS.VizieR/J/A+A/438/201
- Title:
- DG Leo uvby differential photometry
- Short Name:
- J/A+A/438/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multi-site and multi-year differential photometry of the triple star DG Leo reveals a complex frequency spectrum that can be modelled as the combination of at least three {delta} Scuti type frequencies in the range 11.5-13c/d (with semi-amplitudes of 2-7mmag) and a superimposed slow variability of larger amplitude. The period of the slow variation fits very well with half the orbital period of the inner spectroscopic binary indicating the presence of ellipsoidal variations caused by the tidally deformed components in a close configuration. These findings, together with the results of a recent spectroscopic analysis (showing that the system consists of a pair of mild Am stars and one A-type component of normal solar composition), infer that DG Leo is an extremely interesting asteroseismic target. Identification of which component(s) of this multiple system is (or are) pulsating and determination of the excited pulsation modes will both contribute to a much better understanding of the non-trivial link between multiplicity, chemical composition, rotation, and pulsation in the lower part of the classical Cepheid instability strip.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/L45
- Title:
- 3D global climate models for exoplanet around M-star
- Short Name:
- J/ApJ/771/L45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The habitable zone (HZ) is the circumstellar region where a planet can sustain surface liquid water. Searching for terrestrial planets in the HZ of nearby stars is the stated goal of ongoing and planned extrasolar planet surveys. Previous estimates of the inner edge of the HZ were based on one-dimensional radiative-convective models. The most serious limitation of these models is the inability to predict cloud behavior. Here we use global climate models with sophisticated cloud schemes to show that due to a stabilizing cloud feedback, tidally locked planets can be habitable at twice the stellar flux found by previous studies. This dramatically expands the HZ and roughly doubles the frequency of habitable planets orbiting red dwarf stars. At high stellar flux, strong convection produces thick water clouds near the substellar location that greatly increase the planetary albedo and reduce surface temperatures. Higher insolation produces stronger substellar convection and therefore higher albedo, making this phenomenon a stabilizing climate feedback. Substellar clouds also effectively block outgoing radiation from the surface, reducing or even completely reversing the thermal emission contrast between dayside and nightside. The presence of substellar water clouds and the resulting clement surface conditions will therefore be detectable with the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A65
- Title:
- DG Tau B ALMA observations
- Short Name:
- J/A+A/636/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemical composition of planets is determined by the distribution of the various molecular species in the protoplanetary disk at the time of their formation. To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outflow sources in Taurus, we report on new ALMA Band 6 (1.3mm) observations with 0.15" (20au) resolution toward the embedded young star DG Tau B. Images of the continuum emission reveals a dust disk with rings and, putatively, a leading spiral arm. The disk, as well as the prominent outflow cavities, are detected in CO, H_2_CO, CS, and CN; instead, they remain undetected in SO_2_, HDO, and CH_3_OH. From the absorption of the back-side outflow, we inferred that the disk emission is optically thick in the inner 50au. This morphology explains why no line emission is detected from this inner region and poses some limitations toward the calculation of the dust mass and the characterization of the inner gaseous disk. The H_2_CO and CS emission from the inner 200au is mostly from the disk, and their morphology is very similar. The CN emission significantly differs from the other two molecules as it is observed only beyond 150au. This ring-like morphology is consistent with previous observations and the predictions of thermochemical disk models. Finally, we constrained the disk-integrated column density of all molecules. In particular, we found that the CH_3_OH/H_2_CO ratio must be smaller than ~2, making the methanol non-detection still consistent with the only such ratio available from the literature (1.27 in TW Hya).
4399. 3D-HST+CANDELS catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/214/24
- Title:
- 3D-HST+CANDELS catalog
- Short Name:
- J/ApJS/214/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 3D-HST and CANDELS programs have provided WFC3 and ACS spectroscopy and photometry over ~900arcmin^2^ in five fields: AEGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS field. All these fields have a wealth of publicly available imaging data sets in addition to the Hubble Space Telescope (HST) data, which makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range. In this paper we describe a photometric analysis of the CANDELS and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3-8{mu}m. Objects were selected in the WFC3 near-IR bands, and their SEDs were determined by carefully taking the effects of the point-spread function in each observation into account. A total of 147 distinct imaging data sets were used in the analysis.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/5133
- Title:
- 3DHST CANDELS redshift compilation
- Short Name:
- J/MNRAS/475/5133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We established an accurate comparison between observationally and theoretically estimated major merger rates over a large range of mass (logM_bar_/M_{sun}_=9.9-11.4) and redshift (z=0.7-1.6). For this, we combined a new estimate of the merger rate from an exhaustive count of pairs within the virial radius of massive galaxies at z~1.265 and cross-validated with their morphology, with estimates from the morpho-kinematic analysis of two other samples. Theoretical predictions were estimated using semi-empirical models with inputs matching the properties of the observed samples, while specific visibility time-scales scaled to the observed samples were used. Both theory and observations are found to agree within 30 per cent of the observed value, which provides strong support to the hierarchical assembly of galaxies over the probed ranges of mass and redshift. Here, we find that ~60 per cent of population of local massive (M_stellar_=10^10.3-11.6^M_{sun}_) galaxies would have undergone a wet major merger since z=1.5, consistently with previous studies. Such recent mergers are expected to result in the (re-)formation of a significant fraction of local disc galaxies.