- ID:
- ivo://CDS.VizieR/J/MNRAS/476/4965
- Title:
- Weak metal line absorbers sample
- Short Name:
- J/MNRAS/476/4965
- Date:
- 15 Dec 2021 07:14:57
- Publisher:
- CDS
- Description:
- We present a sample of 34 weak metal line absorbers at z<0.3 selected by the simultaneous >3{sigma} detections of the SiII{lambda}1260 and CII{lambda}1334 absorption lines, with W_r_(SiII)<0.2 {AA} and W_r_(CII)<0.3{AA}, in archival HST/COS spectra. Our sample increases the number of known low-z 'weak absorbers' by a factor of >5. The column densities of HI and low-ionization metal lines obtained from Voigt profile fitting are used to build simple photoionization models. The inferred densities and line-of-sight thicknesses of the absorbers are in the ranges of -3.3<logn_H_/cm^-3^<-2.4 and ~1pc-50kpc (median ~=500pc), respectively. Most importantly, 85 per cent (50 per cent) of these absorbers show a metallicity of [Si/H]>-1.0(0.0). The fraction of systems showing near-/supersolar metallicity in our sample is significantly higher than in the HI-selected sample of Wotta et al., and the galaxy-selected sample of Prochaska et al., of absorbers probing the circum-galactic medium at similar redshift. A search for galaxies has revealed a significant galaxy-overdensity around these weak absorbers compared to random positions with a median impact parameter of 166 kpc from the nearest galaxy. Moreover, we find the presence of multiple galaxies in ~=80 per cent of the cases, suggesting group environments. The observed dN/dz of 0.8+/-0.2 indicates that such metal-enriched, compact, dense structures are ubiquitous in the haloes of low-z group galaxies. We suggest that these are transient structures that are related to galactic outflows and/or stripping of metal-rich gas from galaxies.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/660/1093
- Title:
- Weak MgII absorbers at 0.4<z<2.4
- Short Name:
- J/ApJ/660/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey of weak MgII absorbers in the VLT/UVES spectra of 81 QSOs obtained from the ESO archive. In this survey, we identified 112 weak MgII systems within the redshift interval 0.4<z<2.4 with 86% completeness down to a rest-frame equivalent width of Wr(2796)=0.02{AA}, overing a cumulative redshift path length of {DELTA}Z~77.3.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A64
- Title:
- W51/e2 and G34.3+0.2 IRAM spectra
- Short Name:
- J/A+A/582/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With only a few low- and high-mass star-formation regions studied in detail so far, it is unclear what role the environment plays in complex molecule formation. In this light, a comparison of relative abundances of related species between sources might be useful for explaining any observed differences. We seek to measure the relative abundance between three important complex organic molecules, ethylene glycol ((CH_2_OH)_2_), glycolaldehyde (CH_2_OHCHO) and methyl formate (HCOOCH_3_), toward high-mass protostars and thereby provide additional constraints on their formation pathways. We use IRAM30 m single-dish observations of the three species toward two high-mass star-forming regions - W51/e2 and G34.3+0.2 - and report a tentative detection of (CH_2_OH)_2_ toward both sources.
- ID:
- ivo://CDS.VizieR/III/190B
- Title:
- WEB Catalog of Radial Velocities
- Short Name:
- III/190B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We give a common version of the two catalogues of Mean Radial Velocities by Wilson (1953; catalogue <III/21>) and Evans (1978; catalogue <III/47>) to which we have added the catalogue of spectroscopic binary systems (Batten et al. 1989; catalogue <V/64>). For each star, when possible, we give: 1) an acronym to enter SIMBAD (Set of Identifications Measurements and Bibliography for Astronomical Data; see <http://cdsweb.u-strasbg.fr/Simbad.html>) of the CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the number HIC of the HIPPARCOS catalogue (Turon 1992; catalogue <I/196>). 3) the CCDM number (Catalogue des Composantes des etoiles Doubles et Multiples) by Dommanget & Nys (1994; catalogue <I/211>). For the cluster stars, a precise study has been done, on the identification numbers. Numerous remarks point out the problems we have had to deal with.
21355. WeCAPP Survey. M31 variables
- ID:
- ivo://CDS.VizieR/J/A+A/445/423
- Title:
- WeCAPP Survey. M31 variables
- Short Name:
- J/A+A/445/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observations in the WeCAPP microlensing survey towards the Andromeda galaxy (M31) for a period of three years (2000-2003) resulted in a database with unprecedented time coverage for an extragalactic variable star study. We have monitored a 16.1' x 16.6' field centered on the nucleus of M31 in two optical bands (R and I) using the 0.8-m telescope at Wendelstein, Germany and the 1.2-m telescope at Calar Alto, Spain. Using the difference imaging method we detected 23781 variable sources for which we calculated the periods and variation amplitudes. We classified the variables according to their position in the R-band period-amplitude plane. Three groups can be distinguished; while the first two groups can be mainly associated with Cepheid-like variables (population I Cepheids in group I; type II Cepheids and RV Tauri stars in group II), the third one consists of Long Period Variables (LPVs). We detected 37 RV Tauri stars and 11 RV Tauri candidates, which makes this catalogue one of the largest collections of this class of stars to date. The classification scheme is supported by Fourier decomposition of the light curves. The catalogue of variable stars contains the positions, the periods in R and I, the significance of the assigned periods, and the variation amplitudes in the R and I bands.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A37
- Title:
- Well sampled stars FEROS+HARPS radial velocities
- Short Name:
- J/A+A/632/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars show various amounts of Radial Velocity (RV) jitter due to varying stellar activity levels. The typical amount of RV jitter as a function of stellar age and observational timescale has not been systematically quantified so far, although it is often larger than the instrumental precision of modern high-resolution spectrographs used for Doppler planet detection and characterization. We aim to empirically determine the intrinsic stellar RV variation for mostly G and K dwarf stars on different timescales and for different stellar ages independently of stellar models. We also focus on young stars (~<30Myr), where the RV variation is known to be large. We use archival FEROS and HARPS RV data of stars which were observed at least 30 times spread over at least two years. We then apply the Pooled Variance (PV) technique to these data sets to identify the periods and amplitudes of underlying, quasiperiodic signals. We show that the PV is a powerful tool to identify quasiperiodic signals in highly irregularly sampled data sets. We derive activity-lag functions for 20 assumingly single stars stars, where lag is the timescale on which the stellar jitter is measured. Since the ages of all stars are known, we also use this to formulate an activity-age-lag relation which can be used to predict the expected RV jitter of a star given its age and the timescale to be probed. The maximum RV jitter on timescales of decades decreases from over 500m/s for 5Myr old stars to 2.3m/s for stars with ages around 5Gyr. The decrease in RV jitter when considering a time scale of only 1d instead of 1yr is smaller by roughly a factor of 4 for stars with an age of about 5Myr, and a factor of 1.5 for stars with an age of 5Gyr. How fast the RV jitter increases with lag strongly depends on stellar age and reaches 99% of the maximum RV jitter between a few days for a few Myr old stars up to presumably decades or longer for stars with an age of a few Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/15
- Title:
- WERGS. II. SED fitting with optical, IR & radio data
- Short Name:
- J/ApJS/243/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present physical properties of radio galaxies (RGs) with f_1.4GHz_>1mJy discovered by Subaru Hyper Suprime-Cam (HSC) and Very Large Array Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0<z<=1.7 with HSC counterparts in about 100deg^2^, we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150MHz). We derived their color excess (E(B-V)_*_), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity (q_IR_), and radio spectral index ({alpha}_radio_) that are derived from the spectral energy distribution (SED) fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of active galactic nucleus (AGN) component. We found that E(B-V)_*_, SFR, and IR luminosity clearly depend on redshift while stellar mass, q_IR_, and {alpha}_radio_ do not significantly depend on redshift. Since optically faint (i_AB_>=21.3) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared with optically bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population.
- ID:
- ivo://CDS.VizieR/J/A+AS/124/259
- Title:
- Westerbork Northern Sky Survey I.
- Short Name:
- J/A+AS/124/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Westerbork Nortern Sky Survey (WENSS) is a low-frequency (325 MHz) radio survey that will cover the whole sky north of a declination of 30 degrees A first installment of the survey covers an area of 570 square degrees around the North Ecliptic Pole. A source list comprising 11,299 sources and 994 components is listed in Table 6 of the paper. This table is presented here.
- ID:
- ivo://CDS.VizieR/J/A+AS/43/1
- Title:
- Westerbork observations of Galactic Sources
- Short Name:
- J/A+AS/43/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for new Galactic sources from the BG catalogue (Fanti et al., 1974A&AS...16...43F). The observations were made with the Westerbork Synthesis Radiotelescope operating at 1.4GHz, using the short cuts technique. The adopted selection criteria for the observed sample are discussed in detail. For reducing the data we have adopted the Clean and Restore technique. We have also tested the capability of this technique in reproducing the total flux density for the very extended structures. A catalogue of the sources present in each field was produced ; the relevant information about observations and reduction characteristics are given.
- ID:
- ivo://CDS.VizieR/J/A+A/35/393
- Title:
- Westerbork Second Deep Survey
- Short Name:
- J/A+A/35/393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A radio survey has been made of an area centered at 01h 03min +29{deg}, using the Westerbork telescope at 1415MHz. The completeness limit of the survey is 7mJy. Additional observations have been made at 610MHz. The Lick 120" telescope has been used to obtain deep (O98-O2 emulsion) plates to serve as an optical counterpart. A catalogue is presented of 58 sources found in the survey. 53 of these comprise a complete sample. 31 sources of the complete sample lie in areas of which Lick plates were taken. Of the sources in Lick plates areas, 11 could be identified with galaxies and 3 with possible QSO's, yielding an identification percentage of 46. For the other 22 sources an identification programme was carried out using Palomar Sky Survey prints and other large 48" Schmidt plates: three of these sources could be identified with galaxies and two with possible QSO's. The survey was also used to derive source counts and a spectral index distribution. The source counts agree well with those derived for an earlier survey. The spectral index distribution has a mean of 0.52 and a width of 0.39. the explanation for the flatter spectra is not clear but might possibly lie in another source population that begins to dominate the results at low flux densities.
