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4491. NICMOS early-type galaxies
ID:
ivo://CDS.VizieR/J/AJ/127/131
Title:
NICMOS early-type galaxies
Short Name:
J/AJ/127/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
Here we report results for two subsamples of early-type galaxies, defined primarily by their morphologies in the F160W band, which were selected from the NICMOS data down to H160AB<24.0. A primary subsample is defined as the 34 galaxies with early-type galaxy morphologies and early-type galaxy spectral energy distributions. The secondary subsample is defined as those 42 objects that have early-type galaxy morphologies with non-early-type galaxy spectral energy distributions.
4492. NICMOS observations of Mon R2 cluster
ID:
ivo://CDS.VizieR/J/AJ/132/2296
Title:
NICMOS observations of Mon R2 cluster
Short Name:
J/AJ/132/2296
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have analyzed Hubble Space Telescope NICMOS2 F110W-, F160W-, F165M-, and F207M-band images covering the central 1'x1' region of the cluster associated with Mon R2 in order to constrain the initial mass function (IMF) down to 20M_J_. The flux ratio between the F165M and F160W bands was used to measure the strength of the water-band absorption feature and select a sample of 12 out of the total sample of 181 objects that have effective temperatures between 2700 and 3300K.
4493. NICMOS observations of NGC 2024
ID:
ivo://CDS.VizieR/J/AJ/126/1665
Title:
NICMOS observations of NGC 2024
Short Name:
J/AJ/126/1665
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of NICMOS observations of the embedded cluster associated with NGC 2024. An analysis of the cluster color-magnitude diagram (CMD) using the models of D'Antona & Mazzitelli and Baraffe et al. (published in 1997MmSAI..68..807D and 1998, Cat. <J/A+A/337/403>, respectively) indicates that the ratio of intermediate-mass (1.0-10.0M_{sun}_) to low-mass (0.1-1.0M_{sun}_) stars is consistent with the stellar initial mass function (IMF) for the field. In addition to the CMD analysis, we present results on the multiplicity of stars in the region. Three companions (in a sample of 95 potential primaries) were found, with angular separations between 0.4" and 1.0", translating to a projected linear separation of 184-460AU for an estimated distance of 460pc. The completeness of binary detections is assessed using recovery fractions calculated by a series of tests using artificially generated companions to potential primaries in the data frames. We find that the binary fraction in NGC 2024 is consistent with that of Duquennoy & Mayor (published in 1991A&A...248..485D) for solar neighborhood stars over the range of separations and companion masses appropriate for our survey.
4494. NICMOS star formation history
ID:
ivo://CDS.VizieR/J/ApJ/546/694
Title:
NICMOS star formation history
Short Name:
J/ApJ/546/694
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of an extensive analysis of the star formation rates determined from the NICMOS deep images of the northern Hubble Deep Field. We use SED template fitting photometric techniques to determine both the redshift and the extinction for each galaxy in our field. Measurement of the individual extinctions provides a correction for star formation hidden by dust obscuration. We determine star formation rates for each galaxy based on the 1500{AA} UV flux and add the rates in redshift bins of width 1.0 centered on integer redshift values.
4495. Nine new open clusters within 500pc from the Sun
ID:
ivo://CDS.VizieR/J/A+A/595/A22
Title:
Nine new open clusters within 500pc from the Sun
Short Name:
J/A+A/595/A22
Date:
21 Oct 2021
Publisher:
CDS
Description:
One of the results of the Milky Way Star Clusters (MWSC) survey was the detection of a slight under-density of old (ca. 1Gyr) clusters within the nearest kilo-parsec from the Sun. This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal such clusters. We derived proper motions from a combination of Tycho-2 with URAT1, and obtained a mean precision of about 1.4mas/yr per co-ordinate for 1.3 million stars north of -20{deg} declination. We cut the sky into narrow proper motion slices and searched for spatial over-densities of stars in each slice. We then examined stars from over-densities in optical and near-infrared colour-magnitude diagrams to determine if they are compatible with isochrones of a cluster. We estimated the field star contamination using our data and the Besancon Galactic model. We detected nine hitherto unknown open clusters in the vicinity of the Sun with ages between 70Myr and 1Gyr, and distances between 200 and 500pc.
4496. NIR colors of hard X-ray-selected AGN
ID:
ivo://CDS.VizieR/J/ApJ/610/128
Title:
NIR colors of hard X-ray-selected AGN
Short Name:
J/ApJ/610/128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results of near-infrared photometry (J, H, K_s_) for a hard X-ray-selected sample of active galactic nuclei (AGNs) obtained from optical identification of the sources detected in ASCA surveys (total ~75deg^2^) with a flux limit of (1-3)x10^-13^erg/s/cm^2^ (2-10keV). The sample covers the AGNs at 0.1<~z<~1 with L_2-10keV_=10^42^-10^46^erg/s with very high completeness. The near-infrared photometric data of the sample are obtained from the Two Micron All Sky Survey (2MASS, Cat. <II/246>) and observations with Kitt Peak National Observatory 2.1m telescope and the University of Hawaii 2.2m telescope.
4497. NIR counterparts to Chandra X-ray sources. I.
ID:
ivo://CDS.VizieR/J/ApJ/703/30
Title:
NIR counterparts to Chandra X-ray sources. I.
Short Name:
J/ApJ/703/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2{deg}x0.8{deg} of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. We cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10{sigma} limiting flux of Ks<=15.6mag. For each of the infrared matches to X-ray sources in our catalog we derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis.
4498. NIR fluxes of 14 cool variable stars
ID:
ivo://CDS.VizieR/J/PASP/120/1183
Title:
NIR fluxes of 14 cool variable stars
Short Name:
J/PASP/120/1183
Date:
21 Oct 2021
Publisher:
CDS
Description:
New flux data are presented for nine non-variable stars and 14 evolved variable stars with spectral types M and C. The data are from measurements of 21 passbands in the wavelength range from 7440{AA} to 10834{AA}, and they are comparable to measurements made by Wing some 40 years ago. Because the extinction algorithm applied to the new data is based partly on up-to-date calculations of telluric water-vapor effects, those calculations are tested for accuracy. In addition, methods used to calibrate standard stars both outside and inside the Paschen confluence are explained. After reddening corrections are applied to the flux data for the variable stars, those data are used to calculate color temperatures. In turn, those temperatures are used to derive blanketing corrections to color temperatures measured in the Wing filter system. Indices of absorption strength are calculated by comparing the flux data to blackbody colors derived from the color temperatures. It is found that the standard errors of those temperatures range from 3% to less than 1%. For the variable stars, the standard errors for the flux data range from 6.8mmag to 11.6mmag. For the non-variable stars, the corresponding standard error is about 6.0mmag.
4499. NIR galaxy cluster candidates in the SPT survey
ID:
ivo://CDS.VizieR/J/ApJ/761/22
Title:
NIR galaxy cluster candidates in the SPT survey
Short Name:
J/ApJ/761/22
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720deg^2^ of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of {Delta}z/(1+z)=0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z=1.35 with a median of z_med_=0.57. Approximately 18% of the sample with measured redshifts lies at z>0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance {xi}>5 ({xi}>4.5) is >=95% (>=70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples.
4500. NIR Imaging of R136 in 30 Dor
ID:
ivo://CDS.VizieR/J/ApJ/466/254
Title:
NIR Imaging of R136 in 30 Dor
Short Name:
J/ApJ/466/254
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report 0.15" resolution near-infrared (NIR) imaging of R136, the central region of 30 Doradus in the Large Magellanic Cloud. Our 12.8"x12.8" images were recorded with the MPE camera SHARP II at the 3.6m ESO telescope, using the adaptive optics system COME ON+. The high spatial resolution and sensitivity (20th magnitude in K) of our observations allow our H- and K-band images to be compared and combined with recent Hubble Space Telescope (HST) WFPC2 data of R136. We fit theoretical models with variable foreground extinction to the observed magnitudes of ~1000 stars (roughly half of which were detected in HST and NIR bands) and derive the stellar population in this starburst region. We find no red giants or supergiants; however, we detect ~110 extremely red sources which are probably young, pre-main-sequence low- or intermediate-mass stars. We obtained narrow-band images to identify known and new Wolf-Rayet stars by their He II (2.189um) and BrGamma (2.166um) emission lines. The presence of W-R stars and absence of red supergiants narrow the cluster age to 3-5Myr, while the derived ratio of W-R to O stars of 0.05 in the central region favors an age of ~3.5Myr, with a relatively short starburst duration. For the O stars, the core radius is found to be 0.1pc and appears to decrease with increasing stellar mass. The slope of the mass function is Gamma=-1.6 on average, but it steepens with increasing distance from the cluster center from Gamma=-1.3 in the inner 0.4pc to Gamma=-2.2 outside 0.8pc for stars more massive than 12 Msun. The radial variation of the mass function reveals strong mass segregation that is probably due to the cluster's dynamical evolution.