- ID:
- ivo://CDS.VizieR/J/ApJ/737/44
- Title:
- Deuterated chemistry of the early universe
- Short Name:
- J/ApJ/737/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A comprehensive chemistry of the highly deuterated species D_2_, D^+^_2_, D_2_H^+^, and D^+^_3_ in the early universe is presented. Fractional abundances for each are calculated as a function of redshift z in the recombination era. The abundances of the isotopologues are found to display similar behavior. Fractionation enhances the abundances of most of the more highly deuterated species as the redshift decreases due to the closing of some reaction channels as the gas temperature cools. Rate coefficients for the majority of the reactions involving the deuterated species are uncertain resulting in a corresponding uncertainty in their predicted abundances.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/585/A36
- Title:
- Deuterated water in prestellar cores
- Short Name:
- J/A+A/585/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on new APEX observations of the ground state 1_0,1_-0_0,0_ HDO transition at 464.92452GHz toward the prestellar core L1544. The line is undetected and we present an extensive study on the conditions for its detectability in cold and dense cloud cores. The water and deuterated water abundances have been estimated using an advanced chemical model simplified for the limited number of reactions or processes that are active in cold regions (<15K). We use the LIME radiative transfer code to compute the expected intensity and profile of both H_2_O and HDO lines and compare them with the observations. We present several ad hoc profiles that best-fit the observations and compare the profiles with results from an astrochemical modeling, coupling gas phase and grain surface chemistry. Our comparison between observations, radiative transfer and chemical modeling shows the limits of detectability for singly deuterated water with single-dish telescopes as well as interferometric observations.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A87
- Title:
- Deuteration in massive star formation process
- Short Name:
- J/A+A/575/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in the low- and the high-mass star formation process. However, the role of surface chemistry in these studies has not been quantified from an observational point of view. In order to compare how the deuterated fractions of species formed only in the gas and partially or uniquely on grain surfaces evolve with time, we observed rotational transitions of CH_3_OH, ^13^CH_3_OH, CH_2_DOH, CH_3_OD at 3 and 1.3mm, and of NH_2_D at 3mm with the IRAM-30m telescope, and the inversion transitions (1,1) and (2,2) of NH_3_ with the GBT, towards most of the cores already observed by Fontani et al. (2011A&A...529L...7F, 2014MNRAS.440..448F) in N_2_H^+^, N_2_D^+^, HNC, DNC. NH_2_D is detected in all but two cores, regardless of the evolutionary stage. Dfrac(NH_3_) is on average above 0.1, and does not change significantly from the earliest to the most evolved phases, although the highest average value is found in the protostellar phase (~0.3). Few lines of CH_2_DOH and CH_3_OD are clearly detected, and only towards protostellar cores or externally heated starless cores. This work clearly confirms an expected different evolutionary trend of the species formed exclusively in the gas (N_2_D^+^ and N_2_H^+^) and those formed partially (NH_2_D and NH_3_) or totally (CH_2_DOH and CH_3_OH) on grain mantles. The study also reinforces the idea that Dfrac(N_2_H^+^) is the best tracer of massive starless cores, while high values of Dfrac(CH_3_OH) seem rather good tracers of the early protostellar phases, at which the evaporation/sputtering of the grain mantles is most efficient.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2907
- Title:
- 3D extinction map of northern Galactic plane
- Short Name:
- J/MNRAS/443/2907
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a three dimensional map of extinction in the Northern Galactic Plane derived using photometry from the IPHAS survey. We construct the map using a method based on a hierarchical Bayesian model as previously described by Sale (2012MNRAS.427.2119S). In addition to mean extinction, we also measure differential extinction, which arises from the fractal nature of the ISM. The method applied also furnishes us with photometric estimates of the distance, extinction, effective temperature, surface gravity, and mass for ~38 million stars. Further details about the data as well as additional formats and data products are available via http://www.iphas.org/extinction.
4385. 6dF-DR2 Galaxy Survey
- ID:
- ivo://CDS.VizieR/VII/249
- Title:
- 6dF-DR2 Galaxy Survey
- Short Name:
- VII/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 6dF Galaxy Survey is measuring around 150000 redshifts and 15000 peculiar velocities from galaxies over the southern sky at |b|>10{deg}. When complete, it will be the largest survey of its kind by more than an order of magnitude. A total of 83014 sources now have their spectra, redshifts, and near-infrared and optical photometry available online and searchable through an Structured Query Language at www.wfau.roe.ac.uk/6dFGS/ .
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/87
- Title:
- 2dF Galaxy Redshift Survey: galaxy clusters
- Short Name:
- J/MNRAS/329/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a study of known clusters within the 2dF Galaxy Redshift Survey (2dFGRS, Cat. <VII/226>) observed areas and have identified 431 Abell, 173 APM and 343 EDCC clusters. Precise redshifts, velocity dispersions and new centroids have been measured for the majority of these objects, and this information is used to study the completeness of these catalogues, the level of contamination from foreground and background structures along the cluster's line of sight, the space density of the clusters as a function of redshift, and their velocity dispersion distributions. We find that the Abell and EDCC catalogues are contaminated at the level of about 10 per cent, whereas the APM catalogue suffers only 5 per cent contamination. If we use the original catalogue centroids, the level of contamination rises to approximately 15 per cent for the Abell and EDCC catalogues, showing that the presence of foreground and background groups may alter the richness of clusters in these catalogues. There is a deficiency of clusters at z~0.05 hat may correspond to a large underdensity in the Southern hemisphere. From the cumulative distribution of velocity dispersions for these clusters, we derive a space density of {sigma}>1000km/s clusters of 3.6x10^-6^h^3^/Mpc^3^. This result is used to constrain models for structure formation; our data favour low-density cosmologies, subject to the usual assumptions concerning the shape and normalization of the power spectrum.
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/227
- Title:
- 2dF Galaxy Redshift Survey. II.
- Short Name:
- J/MNRAS/329/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have cross-matched the 1.4-GHz NRAO VLA Sky Survey (NVSS, Condon 1998, Cat. <VIII/65>) with the first 210 fields observed in the 2dF Galaxy Redshift Survey (2dFGRS, Colless, 2001, Cat. <VII/226>), covering an effective area of 325{deg}^2^ (about 20 per cent of the final 2dFGRS area). This yields a set of optical spectra of 912 candidate NVSS counterparts, of which we identify 757 as genuine radio identifications - the largest and most homogeneous set of radio source spectra ever obtained. The 2dFGRS radio sources span the redshift range z=0.005 to 0.438, and are a mixture of active galaxies (60 per cent) and star-forming galaxies (40 per cent). About 25 per cent of the 2dFGRS radio sources are spatially resolved by NVSS, and the sample includes three giant radio galaxies with projected linear size greater than 1 Mpc. The high quality of the 2dF spectra means we can usually distinguish unambiguously between AGN and star-forming galaxies. We make a new determination of the local radio luminosity function at 1.4 GHz for both active and star-forming galaxies, and derive a local star formation density of 0.022+/-0.004M_{sun}_/yr/Mpc^3^ (H_0_=50km/s/Mpc)
- ID:
- ivo://CDS.VizieR/VII/259
- Title:
- 6dF galaxy survey final redshift release
- Short Name:
- VII/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The final redshift release of the 6dF Galaxy Survey (6dFGS) is a combined redshift and peculiar velocity survey over the southern sky (|b|>10{deg}). Its 136304 spectra have yielded 110256 new extragalactic redshifts and a new catalogue of 125071 galaxies making near-complete samples with limits in (K, H, J, rF, bJ) (12.65, 12.95, 13.75, 15.60, 16.75). The median redshift of the survey is 0.053. The catalog includes basic data for the galaxies in the 6dFGS with redshifts, using the best 6dFGS redshifts (Q=3 or 4) plus available redshifts from SDSS, 2dFGRS and ZCAT (124647 entries in all). It supersedes the previous DR2 version (Cat. VII/249). The URL of the 6dFGS data base is: http://www-wfau.roe.ac.uk/6dFGS
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/1231
- Title:
- 6dF Galaxy Survey: Fundamental Plane data
- Short Name:
- J/MNRAS/443/1231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the 6dFGS Fundamental Plane (6dFGSv) catalogue that is used to estimate distances and peculiar velocities for nearly 9000 early-type galaxies in the local (z<0.055) universe. Velocity dispersions are derived by cross-correlation from 6dF V-band spectra with typical S/N of 12.9{AA}^-1^ for a sample of 11315 galaxies; the median velocity dispersion is 163km/s and the median measurement error is 12.9 per cent. The photometric Fundamental Plane (FP) parameters (effective radii and surface brightnesses) are determined from the JHK 2MASS images for 11102 galaxies. Comparison of the independent J- and K-band measurements implies that the average uncertainty in X_FP_, the combined photometric parameter that enters the FP, is 0.013dex (3 per cent) for each band. Visual classification of morphologies was used to select a sample of nearly 9000 early-type galaxies that form 6dFGSv. This catalogue has been used to study the effects of stellar populations on galaxy scaling relations, to investigate the variation of the FP with environment and galaxy morphology, to explore trends in stellar populations through, along and across the FP, and to map and analyse the local peculiar velocity field.
- ID:
- ivo://CDS.VizieR/J/MNRAS/348/866
- Title:
- 2dFGRS Percolation-Inferred Galaxy Group (2PIGG)
- Short Name:
- J/MNRAS/348/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The construction of a catalogue of galaxy groups from the Two-degree Field Galaxy Redshift Survey (2dFGRS) is described. Groups are identified by means of a friends-of-friends percolation algorithm which has been thoroughly tested on mock versions of the 2dFGRS generated from cosmological N-body simulations. The tests suggest that the algorithm groups all galaxies that it should be grouping, with an additional 40 per cent of interlopers. About 55 per cent of the ~190000 galaxies considered are placed into groups containing at least two members of which ~29000 are found. Of these, ~7000 contain at least four galaxies, and these groups have a median redshift of 0.11 and a median velocity dispersion of 260km/s. This 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue represents the largest available homogeneous sample of galaxy groups.