- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2844
- Title:
- Radial metallicity gradient from RAVE DR3
- Short Name:
- J/MNRAS/419/2844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate radial metallicity gradients for a sample of dwarf stars from the RAdial Velocity Experiment (RAVE) Data Release 3 (DR3, Cat. III/265). We select a total of approximately 17000 F-type and G-type dwarfs, using a selection of colour, log g and uncertainty in the derived space motion, and calculate for each star a probabilistic (kinematic) population assignment to a thick or thin disc using space motion and additionally another (dynamical) assignment using stellar vertical orbital eccentricity. We additionally subsample by colour, to provide samples biased toward young thin-disc and older thin-disc stars. We derive a metallicity gradient as a function of Galactocentric radial distance, i.e. d[M/H]/dRm=-0.051+/-0.005dex/kpc, for the youngest sample, F-type stars with vertical orbital eccentricities e_v_<=0.04. Samples biased toward older thin-disc stars show systematically shallower abundance gradients.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4193
- Title:
- Radial velocities of 1453 FGK
- Short Name:
- J/MNRAS/472/4193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second paper of a series of publications aiming at obtaining a better understanding regarding the nature of type Ia supernovae (SN Ia) progenitors by studying a large sample of detached F, G and K main-sequence stars in close orbits with white dwarf companions (i.e. WD+FGK binaries). We employ the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) data release 4 spectroscopic data base together with Galaxy Evolution Explorer (GALEX) ultraviolet fluxes to identify 1549 WD+FGK binary candidates (1057 of which are new), thus doubling the number of known sources. We measure the radial velocities of 1453 of these binaries from the available LAMOST spectra and/or from spectra obtained by us at a wide variety of different telescopes around the globe. The analysis of the radial velocity data allows us to identify 24 systems displaying more than 3{sigma} radial velocity variation that we classify as close binaries. We also discuss the fraction of close binaries among WD+FGK systems, which we find to be ~10 per cent, and demonstrate that high-resolution spectroscopy is required to efficiently identify double-degenerate SN Ia progenitor candidates.
- ID:
- ivo://CDS.VizieR/J/ApJS/249/22
- Title:
- Radial velocity variable stars from LAMOST DR4
- Short Name:
- J/ApJS/249/22
- Date:
- 25 Oct 2021 00:46:50
- Publisher:
- CDS
- Description:
- Radial velocity (RV) variable stars are important in astrophysics. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic survey has provided ~6.5 million stellar spectra in its Data Release 4 (DR4). During the survey ~4.7 million unique sources were targeted and ~1 million stars observed repeatedly. The probabilities of stars being RV variables are estimated by comparing the observed RV variations with simulated ones. We build a catalog of 80702 RV variable candidates with probability greater than 0.60 by analyzing the multi-epoch sources covered by LAMOST DR4. Simulations and cross-identifications show that the purity of the catalog is higher than 80%. The catalog consists of 77% binary systems and 7% pulsating stars as well as 16% pollution by single stars. 3138 RV variables are classified through cross-identifications with published results in literatures. By using the 3138 sources common in both LAMOST and a collection of published RV variable catalogs, we are able to analyze LAMOST's RV variable detection rate. The efficiency of the method adopted in this work relies not only on the sampling frequency of observations but also periods and amplitudes of RV variables. With the progress of LAMOST, Gaia, and other surveys, more and more RV variables will be confirmed and classified.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/27
- Title:
- Radio Ammonia Mid-plane Survey (RAMPS) pilot survey
- Short Name:
- J/ApJS/237/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Radio Ammonia Mid-Plane Survey (RAMPS) is a molecular line survey that aims to map a portion of the Galactic midplane in the first quadrant of the Galaxy (l=10{deg}-40{deg}, |b|<=0.4{deg}) using the Green Bank Telescope. We present results from the pilot survey, which has mapped approximately 6.5 square degrees in fields centered at l=10{deg}, 23{deg}, 24{deg}, 28{deg}, 29{deg}, 30{deg}, 31{deg}, 38{deg}, 45{deg}, and 47{deg}. RAMPS observes the NH3 inversion transitions NH_3_(1,1)-(5,5), the H_2_O 6_1,6_-5_2,3_ maser line at 22.235GHz, and several other molecular lines. We present a representative portion of the data from the pilot survey, including NH_3_(1,1) and NH_3_(2,2) integrated intensity maps, H_2_O maser positions, maps of NH_3_ velocity, NH_3_ line width, total NH_3_ column density, and NH_3_ rotational temperature.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/285
- Title:
- Radio and IR counterparts of BLAST sources in CDFS
- Short Name:
- J/ApJ/703/285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at >=5{sigma} over ~9deg^2^ centered on the Chandra Deep Field South by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350, and 500um. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted spectral energy distributions to the BLAST fluxes and fluxes at 70 and 160um acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/submillimeter luminosities, and star formation rates for each source. Our findings show that, on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submillimeter sources detected in surveys conducted at 850um. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multiwavelength catalog of >=5{sigma} BLAST sources contained within the complete ~9deg^2^ survey area.
- ID:
- ivo://CDS.VizieR/J/A+A/416/35
- Title:
- Radio Emission from VLA FIRST Survey AGN
- Short Name:
- J/A+A/416/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the most recent (April 2003) version of the VLA FIRST survey radio catalog (Cat. <VIII/71>), we have searched for radio emission from >2800 AGN taken from the most recent (2001) version of the Veron-Cetty and Veron AGN catalog (Cat. <VII/224>, superseded by 2003, Cat. <VII/235>). These AGN lie in the ~9033 square degrees of sky already covered by the VLA FIRST survey. Our work has resulted in positive detection of radio emission from 775 AGN of which 214 are new detections at radio wavelengths.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2237
- Title:
- Radio-excess IR galaxies PMN/FSC sample selection
- Short Name:
- J/AJ/126/2237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 178 extragalactic objects is defined by correlating the 60{mu}m IRAS Faint Source Catalog (FSC, Cat. <II/156>) with the 5GHz Parkes-MIT-NRAO (PMN, Cat. <VIII/38>) catalog.
- ID:
- ivo://CDS.VizieR/J/MNRAS/354/485
- Title:
- Radio flux of 15-GHz 9C survey
- Short Name:
- J/MNRAS/354/485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out extensive radio and optical follow-up of 176 sources from the 15-GHz 9th Cambridge survey. Optical identifications have been found for 155 of the radio sources; optical images are given with radio maps overlaid. The continuum radio spectrum of each source spanning the frequency range 1.4-43GHz is also given.
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/2731
- Title:
- Radio galaxies in ZFOURGE/NMBS
- Short Name:
- J/MNRAS/455/2731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to reproduce the high-mass end of the galaxy mass distribution, some process must be responsible for the suppression of star formation in the most massive of galaxies. Commonly active galactic nuclei (AGN) are invoked to fulfil this role, but the exact means by which they do so is still the topic of much debate, with studies finding evidence for both the suppression and enhancement of star formation in AGN hosts. Using the ZFOURGE (FourStar Galaxy Evolution) and NMBS (Newfirm Medium Band Survey) galaxy surveys, we investigate the host galaxy properties of a mass-limited (M>=10^10.5^M_{sun}_), high-luminosity (L_1.4_>10^24^W/Hz) sample of radio-loud AGN to a redshift of z=2.25. In contrast to low-redshift studies, which associate radio-AGN activity with quiescent hosts, we find that the majority of z>1.5 radio-AGN are hosted by star-forming galaxies. Indeed, the stellar populations of radio-AGN are found to evolve with redshift in a manner that is consistent with the non-AGN mass-similar galaxy population. Interestingly, we find that the radio-AGN fraction is constant across a redshift range of 0.25<=z<2.25, perhaps indicating that the radio-AGN duty cycle has little dependence on redshift or galaxy type. We do however see a strong relation between the radio-AGN fraction and stellar mass, with radio-AGN becoming rare below ~ 10^10.5^M_{sun}_ or a halo mass of 10^12^M_{sun}_. This halo-mass threshold is in good agreement with simulations that initiate radio-AGN feedback at this mass limit. Despite this, we find that radio-AGN host star formation rates are consistent with the non-AGN mass-similar galaxy sample, suggesting that while radio-AGN are in the right place to suppress star formation in massive galaxies they are not necessarily responsible for doing so.
1340. Radio-loud AGN in SDSS
- ID:
- ivo://CDS.VizieR/J/MNRAS/362/9
- Title:
- Radio-loud AGN in SDSS
- Short Name:
- J/MNRAS/362/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 2712 radio-luminous galaxies is defined from the second data release of the Sloan Digital Sky Survey (SDSS) by cross-comparing the main spectroscopic galaxy sample with two radio surveys: the National Radio Astronomy Observatories (NRAO) Very Large Array (VLA) Sky Survey (NVSS, <VIII/65>) and the Faint Images of the Radio Sky at Twenty centimeters (FIRST, <VIII/71>) survey. The comparison is carried out in a multistage process and makes optimal use of both radio surveys by exploiting the sensitivity of the NVSS to extended and multicomponent radio sources in addition to the high angular resolution of the FIRST images. A radio source sample with 95 per cent completeness and 98.9% reliability is achieved, far better than would be possible for this sample if only one of the surveys was used. The radio source sample is then divided into two classes: radio-loud active galactic nuclei (AGN) and galaxies in which the radio emission is dominated by star formation. The division is based on the location of a galaxy in the plane of 4000{AA} break strength versus radio luminosity per unit stellar mass and provides a sample of 2215 radio-loud AGN and 497 star-forming galaxies brighter than 5mJy at 1.4GHz. A full catalogue of positions and radio properties is provided for these sources.
