- ID:
- ivo://CDS.VizieR/J/ApJ/864/144
- Title:
- N/O and Ne/O ratios of SDSS dwarf galaxies
- Short Name:
- J/ApJ/864/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study how the void environment affects the chemical evolution of galaxies in the universe by comparing the oxygen and nitrogen abundances of dwarf galaxies in voids with dwarf galaxies in denser regions. Using spectroscopic observations from the Sloan Digital Sky Survey Data Release 7, we estimate the oxygen, nitrogen, and neon abundances of 889 void dwarf galaxies and 672 dwarf galaxies in denser regions. We use the Direct T_e_ method for calculating the gas-phase chemical abundances in the dwarf galaxies because it is best suited for low-metallicity, low-mass (dwarf) galaxies. A substitute for the [OII]{lambda}3727 doublet is developed, permitting oxygen abundance estimates of SDSS dwarf galaxies at all redshifts with the Direct T_e_ method. We find that void dwarf galaxies have about the same oxygen abundance and Ne/O ratio as dwarf galaxies in denser environments. However, we find that void dwarf galaxies have slightly higher neon (~10%) abundances than dwarf galaxies in denser environments. The opposite trend is seen in both the nitrogen abundance and N/O ratio: void dwarf galaxies have slightly lower nitrogen abundances (~5%) and lower N/O ratios (~7%) than dwarf galaxies in denser regions. Therefore, we conclude that the void environment has a slight influence on dwarf galaxy chemical evolution. Our mass-N/O relationship shows that the secondary production of nitrogen commences at a lower stellar mass in void dwarf star-forming galaxies than in dwarf star-forming galaxies in denser environments. We also find that star-forming void dwarf galaxies have higher HI masses than the star-forming dwarf galaxies in denser regions. Our star-forming dwarf galaxy sample demonstrates a strong anti-correlation between the sSFR and N/O ratio, providing evidence that oxygen is produced in higher-mass stars than those which synthesize nitrogen. The lower N/O ratios and smaller stellar mass for secondary nitrogen production seen in void dwarf galaxies may indicate both delayed star formation as predicted by {Lambda}CDM cosmology and a dependence of cosmic downsizing on the large-scale environment. A shift toward slightly higher oxygen abundances and higher HI masses in void dwarf galaxies could be evidence of larger ratios of dark matter halo mass to stellar mass in voids compared with denser regions.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/128/1558
- Title:
- NOAO Fundamental Plane Survey
- Short Name:
- J/AJ/128/1558
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce the NOAO Fundamental Plane Survey (NFPS), a wide-field imaging/spectroscopic study of rich, low-redshift galaxy clusters. The survey targets X-ray-selected clusters at 0.010<z<0.067, distributed over the whole sky, with imaging and spectroscopic observations obtained for 93 clusters. This data set will be used in investigations of galaxy properties in the cluster environment and of large-scale velocity fields through the fundamental plane. In this paper, we present details of the cluster sample construction and the strategies employed to select early-type galaxy samples for spectroscopy. Details of the spectroscopic observations are reported. From observations of 5479 red galaxies, we present redshift measurements for 5388 objects and internal velocity dispersions for 4131. The velocity dispersions have a median estimated error ~7%. The NFPS has ~15% overlap with previously published velocity dispersion data sets. Comparisons to these external catalogs are presented and indicate typical external errors of ~8%.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A7
- Title:
- NOEMA redshift of bright Herschel galaxies
- Short Name:
- J/A+A/635/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have conducted a program to measure redshifts for thirteen bright galaxies detected in the Herschel Astrophysical Large Area Survey (H-ATLAS) with S(500)>=80mJy. We report reliable spectroscopic redshifts for twelve individual sources, which are derived from scans of the 3 and 2-mm bands, covering up to 31GHz in each band, and are based on the detection of at least two emission lines. The spectroscopic redshifts are in the range between 2.08<z<4.05 with a median value of z=2.9+/-0.6. The sources are unresolved or barely resolved on scales of 10kpc. In one field, two galaxies with different redshifts were detected. In two cases, the sources are found to be binary galaxies with projected distances of ~140kpc. The linewidths of the sources are large, with a mean value for the full width at half maximum of 700+/-300km/s and a median of 800km/s. We analyze the nature of the sources with currently available ancillary data to determine if they are lensed or hyper-luminous (LFIR>10^13^L_{sun}_) galaxies. We also present a re-analysis of the spectral energy distributions including the continuum flux densities measured at 3 and 2-mm to derive overall properties of the sources. Future prospects based on these efficient measurements of redshifts of high-z galaxies using NOEMA are outlined, including a comprehensive survey of all the brightest Herschel galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/837/42
- Title:
- N/O ratio of dwarf galaxies from SDSS
- Short Name:
- J/ApJ/837/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine how the cosmic environment affects the chemical evolution of galaxies in the universe by comparing the N/O ratio of dwarf galaxies in voids with that of dwarf galaxies in denser regions. Ratios of the forbidden [OIII] and [SII] transitions provide estimates of a region's electron temperature and number density. We estimate the abundances of oxygen and nitrogen using these temperature and density estimates and the emission-line fluxes [OII]3727, [OIII]4959,5007, and [NII]6548,6584 with the direct T_e_ method. Using spectroscopic observations from the Sloan Digital Sky Survey Data Release 7, we are able to estimate the N/O ratio in 42 void dwarf galaxies and 89 dwarf galaxies in denser regions. The N/O ratio for void dwarfs (M_r_>-17) is slightly lower (~12%) than for dwarf galaxies in denser regions. We also estimate the nitrogen and oxygen abundances of 2050 void galaxies and 3883 galaxies in denser regions with M_r_>-20. These somewhat brighter galaxies (but still fainter than L_*_) also display similar minor shifts in the N/O ratio. The shifts in the average and median element abundance values in all absolute magnitude bins studied are in the same direction, suggesting that the large-scale environment may influence the chemical evolution of galaxies. We discuss possible causes of such a large-scale environmental dependence of the chemical evolution of galaxies, including retarded star formation and a higher ratio of dark matter halo mass to stellar mass in void galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/125/2064
- Title:
- Northern Optical Cluster Survey. II.
- Short Name:
- J/AJ/125/2064
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, objectively defined catalog of candidate galaxy clusters based on the galaxy catalogs from the digitized Second Palomar Observatory Sky Survey. This cluster catalog, derived from the best calibrated plates in the high-latitude (|b|>30{deg}) northern Galactic cap region, covers 5800deg^2^ and contains 8155 candidate clusters. A simple adaptive kernel density mapping technique, combined with the SExtractor object detection algorithm, is used to detect galaxy overdensities, which we identify as clusters. Simulations of the background galaxy distribution and clusters of varying richnesses and redshifts allow us to optimize detection parameters and measure the completeness and contamination rates for our catalog. Cluster richnesses and photometric redshifts are measured, using integrated colors and magnitudes for each cluster. An extensive spectroscopic survey is used to confirm the photometric results. This catalog, with well-characterized sample properties, provides a sound basis for future studies of cluster physics and large-scale structure.
- ID:
- ivo://CDS.VizieR/J/AJ/137/2981
- Title:
- Northern Optical Cluster Survey. III.
- Short Name:
- J/AJ/137/2981
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the complete galaxy cluster catalog from the Northern Sky Optical Cluster Survey, a new, objectively defined catalog of candidate galaxy clusters at z<~0.25 drawn from the Digitized Second Palomar Observatory Sky Survey (DPOSS). The data presented here cover the Southern Galactic Cap, as well as the less well-calibrated regions of the Northern Galactic Cap. In addition, due to improvements in our cluster finder and measurement methods, we provide an updated catalog for the well-calibrated Northern Galactic Cap region previously published in Paper II (Cat. J/AJ/125/2064). The complete survey covers 11411deg^2^, with over 15000 candidate clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1017
- Title:
- Northern Optical Cluster Survey. IV.
- Short Name:
- J/AJ/128/1017
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an optically selected galaxy cluster catalog from 2700{deg}^2^ of the digitized Second Palomar Observatory Sky Survey (DPOSS), spanning the redshift range 0.1~<z~<0.5, providing an intermediate-redshift supplement to the previous DPOSS cluster survey. This new catalog contains 9956 cluster candidates and is the largest resource of rich clusters in this redshift range to date.
- ID:
- ivo://CDS.VizieR/J/A+A/300/323
- Title:
- NOT GL survey of multiply imaged quasars
- Short Name:
- J/A+A/300/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A gravitational lens (GL)-search program, initiated in 1990 at the Nordic Optcal Telescope (NOT), has revealed several possible GL-candidates among a sample of 168 quasars (QSOs), chosen from three lists compiled by C. Hazard, D. Reimers and J. Surdej, respectively. Some of these candidates, selected for having close companions (within 5 arcseconds), were imaged in several filters and their colours compared. Low dispersion spectra of the most promising candidates were also obtained at the NOT and ESO New Technology Telescope (NTT). None of these has proved to be strong candidates of gravitational lensing effects. We present this new sample of QSOs and combine it with previously published optical QSO samples in a statistical analysis to yield constraints on flat cosmologies and galaxy velocity dispersions.
- ID:
- ivo://CDS.VizieR/J/AJ/120/2206
- Title:
- NTT, HDF-S and HDF-N photometric redshifts
- Short Name:
- J/AJ/120/2206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and compare in this paper new photometric redshift catalogs of the galaxies in three public fields: the NTT Deep Field, the HDF-N, and the HDF-S. In the case of the NTT Deep Field, we present here a new photometric catalog, obtained by combining the existing BVrI and JKs with new deep U observations acquired with NTT-SUSI2, and which includes also the contiguous field centered on the z_em_=4.7 quasar BR 1202-0
- ID:
- ivo://CDS.VizieR/J/A+A/439/487
- Title:
- Nuker law fits of radio galaxies
- Short Name:
- J/A+A/439/487
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Nuker law fits of brightness profiles of a number of radio galaxies that were observed with the HST. The data on B2 radio galaxies were described in Capetti et al. (2000A&A...362..871C), while a number of 3C galaxies with FR II radio structure were taken from the HST archive. The profiles are compared with other samples of early type galaxies, taken from the literature. We find that radio galaxies always have "core"-type profiles, i.e. a shallow profile in the inner part of the galaxy, while radio-quiescent ellipticals may either have "core"-type or "power-law" type profiles.
