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2431. NLS1s 2MASS and WISE photometry
ID:
ivo://CDS.VizieR/J/other/NewA/54.30
Title:
NLS1s 2MASS and WISE photometry
Short Name:
J/other/NewA/54.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The infrared photometric study of SDSS selected Narrow Line Seyfert 1 Galaxies (NLS1s) is presented in this paper. We have made cross-identifications for such NLS1s with 2MASS and WISE observations. Finally 992 NLS1s have 2MASS and WISE counterparts. Comparisons of NLS1s with the Broad Line Seyfert 1 (BLS1s) and Seyfert 2 galaxies are made. It is shown that from 1um to 5um NLS1s are redder than BLS1s and Seyfert 2 galaxies possibly due to the richer dust environment in NLS1 nuclei or to the orientation effect while in the longer wavelengths those three kinds of sources have quite similar behavior indicative of radiation mainly from the similar warm starburst-related dust and the related AGN dust. In addition, relations between infrared colors and related (to H{beta}) strengths of some important lines are also investigated. The results show that the related strengths of [FeII] 4570{AA} are positively correlated with infrared colors in the 1-5um region, but negatively correlated with infrared colors in the 12-22um region; the related strength of [OIII] 5007{AA} are negatively correlated with infrared colors in the 1-5um region, but positively correlated with infrared colors in the 12-22um region; the related strength of [NII]6583{AA} are also negatively correlated with infrared colors in the 1-5um region, but positively correlated with infrared colors in the 12-22um region. Therefore it is indicated that the behavior of [FeII] 4570{AA} is just opposed to that for [OIII] 5007{AA} and [NII] 6583{AA} This result may be caused by different origins of such lines.
2432. 420nm CN and G bands in G8-K5 spectra
ID:
ivo://CDS.VizieR/II/41
Title:
420nm CN and G bands in G8-K5 spectra
Short Name:
II/41
Date:
21 Oct 2021
Publisher:
CDS
Description:
Measurements of the {lambda}4200{AA} CN band are presented for 712 late-type stars. G band data are also included for 212 of these stars. Mean errors of absolute magnitudes derived from CN intensities are at least 1.5 mag. Spectral type determined by G band intensity has a mean deviation of 0.15 class from the MK type for G to K1 stars. The file photom.dat contains 712 data records in the form of CN ratios and G-band ratios, with annotations. The CN ratio is the ratio of the sum of the intensities in the 4097-4149{AA} and 4230-4283{AA} wavelength ranges to the intensity in the 4164-4214{AA} range. The latter contains the CN absorption band, and the first two ranges serve as nearby continuum references. The ratio is a measure of the depth of the absorption in the CN band. Values greater than 2 indicate absorption in the band. The G-band ratio is similarly the ratio of the sum of the intensities in the 4230-4270{AA} and 4342-4380{AA} wavelength ranges to the intensity in the 4285-4315{AA} range.
2433. N/O and Ne/O ratios of SDSS dwarf galaxies
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.
2434. NOFS astrometric measurements for distant WDs
ID:
ivo://CDS.VizieR/J/ApJS/239/26
Title:
NOFS astrometric measurements for distant WDs
Short Name:
J/ApJS/239/26
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents new trigonometric parallaxes and proper motions for 214 stars. The measurements were made at the US Naval Observatory Flagstaff Station between 1989 and 2017, and the average uncertainty in the parallax values is 0.6mas. We find good agreement with Gaia Data Release 2 measurements for the stars in common, although there may be a small systematic offset similar to what has been found by other investigators. The sample is matched to catalogs and the literature to create a photometric data set that spans the ultraviolet to the mid-infrared. New mid-infrared photometry is obtained for 19 stars from archived Spitzer mosaics. New optical spectroscopy is presented for seven systems and additional spectra were obtained from the literature. We identify a subsample of 179 white dwarfs (WDs) at distances of 25-200pc. Their spectral energy distributions (SEDs) are analyzed using model atmospheres. The models reproduce the entire flux-calibrated SED very well and provide the atmospheric chemical composition, temperature, surface gravity, mass, and cooling age of each WD. Twenty-six WDs are newly classified, and 12 systems are presented as candidate unresolved binaries. We confirm one WD+red dwarf system and identify two WDs as candidate dust disk systems. Twelve old and high-velocity systems are identified as candidate thick disk or halo objects. The WDs in the sample generally have Galactic disk-like ages of <8Gyr and masses close to the canonical 0.6M_{sun}_.
2435. NOMAD Catalog
ID:
ivo://CDS.VizieR/I/297
Title:
NOMAD Catalog
Short Name:
I/297
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Naval Observatory Merged Astrometric Dataset (NOMAD) contains astrometric and photometric data for over 1 billion stars derived from the Hipparcos (I/239), Tycho-2 (I/259), UCAC2 (I/289), and USNO-B1.0 (I/284) catalogs for astrometry and optical photometry, supplemented by 2MASS (II/246) near-infrared photometry. For each unique star the "best" astrometric and photometric data are chosen from the source catalogs and merged into a single dataset. A sequence of priorities is followed and NOMAD contains flags to identify the source catalogs and gives cross-reference identifications. This first release of NOMAD is not a compiled catalog; that is, if a star is identified in more than 1 of the above mentioned catalogs, only 1 catalog entry is chosen. Thus the local and global systematic errors of the various source catalogs will be present in this version of NOMAD. All source catalogs astrometric data are on the International Celestial Reference System within the limitations of the source catalogs. For more information, see https://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/nomad A dedicated remote query program can be downloaded from http://cdsweb.u-strasbg.fr/doc/cdsclient.html
2436. Non-linear limb-darkening law for LTE models
ID:
ivo://CDS.VizieR/J/A+A/363/1081
Title:
Non-linear limb-darkening law for LTE models
Short Name:
J/A+A/363/1081
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new non-linear limb-darkening law, based on the Least-Squares Method (LSM), is presented. This law is able to describe the intensity distribution much more accurately than any of the old ones given that the differences I(model)-I(fitting) are of some order of magnitude smaller than those derived from other approximations. This new law shows several advantages: it represents well the intensity distribution, the flux is conserved with high accuracy and it permits the use of a single law for the whole HR Diagram since that the bi-parametric laws are only marginally valid in certain range of effective temperatures. The limb-darkening coefficients are computed for the 12 commonly used photometric bands u v b y U B V R I J H K. Bolometric and monochromatic calculations are also available. The computations are presented for 19 metallicities ranging from 10^-5^ up to 10^+1^ solar abundances, with log(g) varying between 0 and 5.0 and effective temperatures between 2000K-50000K. Results for microturbulent velocities of 0, 1, 2, 4, 8 km/s are also available. With this set of data it was possible to investigate, for the first time, the influence of such parameters in the limb-darkening. Limb-brightening, instead of limb-darkening, was detected for some models. It is shown that the limb-darkening coefficients derived using the Flux Conservation Method (FCM) do not describe very well the intensity distribution, mainly near the border of the disk. On the contrary, the present coefficients, based on the LSM, represent very well the function I({mu}) at any part of the disk for any filter or wavelength, log(g), effective temperature, metallicity and microturbulent velocity. The results are presented here as synthetic tables containing the limb-darkening coefficients. The 46 tables announced in the paper are also accessible as the "original.tar" file.
2437. Non-linear limb-darkening law for LTE models. II.
ID:
ivo://CDS.VizieR/J/A+A/401/657
Title:
Non-linear limb-darkening law for LTE models. II.
Short Name:
J/A+A/401/657
Date:
21 Oct 2021
Publisher:
CDS
Description:
As an extension of our previous investigations on stellar atmospheres (Claret, 2000, Cat. <J/A+A/363/1081>), the limb-darkening coefficients for the Geneva and Walraven photometric systems are presented for the first time using the ATLAS and PHOENIX models. They cover a wide range of values of logg, T_eff_, metallicities and microturbulent velocities. In addition to the traditional applications of limb-darkening coefficients, the present ones are now being used in the interpretation of phase shift of B and A-F type pulsating stars.
2438. Non-linear limb-darkening law for LTE models. III.
ID:
ivo://CDS.VizieR/J/A+A/428/1001
Title:
Non-linear limb-darkening law for LTE models. III.
Short Name:
J/A+A/428/1001
Date:
21 Oct 2021
Publisher:
CDS
Description:
Continuing our studies on stellar atmospheres (Claret, 2000, Cat. <J/A+A/363/1081>, 2003, Cat. <J/A+A/401/657>), we present in this paper the limb-darkening coefficients for the Sloan photometric system. The calculations cover a wide range of values of logg, T_eff_, metallicities and microturbulent velocities. The atmosphere models used are ATLAS and PHOENIX. In addition to the traditional applications of the limb-darkening coefficients, the present ones will be useful since the Sloan filters are now being used in the interpretation of light curves of extrasolar transiting planets, for example. The present calculations may also be useful, as a complement, for the Kepler mission, dedicated to the search for terrestrial planets.
2439. Normal spiral galaxies optical and UV photometry
ID:
ivo://CDS.VizieR/J/AJ/140/1975
Title:
Normal spiral galaxies optical and UV photometry
Short Name:
J/AJ/140/1975
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compare the UV-optical colors of a well-defined set of optically selected pre-merger interacting galaxy pairs with those of normal spirals. The shorter wavelength colors show a larger dispersion for the interacting galaxies than for the spirals. This result can best be explained by higher star formation rates on average in the interacting galaxies, combined with higher extinctions on average. This is consistent with earlier studies which found that the star formation in interacting galaxies tends to be more centrally concentrated than in normal spirals, perhaps due to gas being driven into the center by the interaction. As noted in earlier studies, there is a large variation from galaxy to galaxy in the implied star formation rates of the interacting galaxies, with some galaxies having enhanced rates but others being fairly quiescent.
2440. Northern XMM-XXL field AGN catalog
ID:
ivo://CDS.VizieR/J/MNRAS/457/110
Title:
Northern XMM-XXL field AGN catalog
Short Name:
J/MNRAS/457/110
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents a survey of X-ray-selected active galactic nuclei (AGNs) with optical spectroscopic follow-up in a ~18deg^2^ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by XMM-Newton above a limiting flux of F_0.5-10keV_>10^-15^erg/cm2/s was matched to optical (Sloan Digital Sky Survey, SDSS) and infrared (IR; WISE) counterparts. We followed up 3042 sources brighter than r=22.5mag with the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) spectrograph. The spectra yielded a reliable redshift measurement for 2578 AGNs in the redshift range z=0.02-5.0, with 0.5-2keV luminosities ranging from 10^39^-10^46^erg/s. This is currently the largest published spectroscopic sample of X-ray-selected AGNs in a contiguous area. The BOSS spectra of AGN candidates show a distribution of optical line widths which is clearly bimodal, allowing an efficient separation between broad- and narrow-emission line AGNs. The former dominate our sample (70 per cent) due to the relatively bright X-ray flux limit and the optical BOSS magnitude limit. We classify the narrow-emission line objects (22 per cent of the full sample) using standard optical emission line diagnostics: the majority have line ratios indicating the dominant source of ionization is the AGN. A small number (8 per cent of the full sample) exhibit the typical narrow line ratios of star-forming galaxies, or only have absorption lines in their spectra. We term the latter two classes 'elusive' AGN, which would not be easy to identify correctly without their X-ray emission. We also compare X-ray (XMM-Newton), optical colour (SDSS) and and IR (WISE) AGN selections in this field. X-ray observations reveal, by far, the largest number of AGN. The overlap between the selections, which is a strong function of the imaging depth in a given band, is also remarkably small. We show using spectral stacking that a large fraction of the X-ray AGNs would not be selectable via optical or IR colours due to host galaxy contamination. A substantial fraction of AGN may therefore be missed by these longer wavelength selection methods.