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14231. Spectroscopy of of IC4499 red giants
ID:
ivo://CDS.VizieR/J/MNRAS/411/1536
Title:
Spectroscopy of of IC4499 red giants
Short Name:
J/MNRAS/411/1536
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present radial velocity and metallicity measurements for the far southern Galactic globular cluster IC 4499. We selected several hundred target red giant stars in and around the cluster from the 2MASS point source catalogue, and obtained spectra at the near-infrared calcium triplet using the AAOmega spectrograph. Observations of giants in globular clusters M4, M22 and M68 were taken to provide radial velocity and metallicity comparison objects.
14232. Spectroscopy of Planetary Nebulae in NGC 5128
ID:
ivo://CDS.VizieR/J/A+A/574/A109
Title:
Spectroscopy of Planetary Nebulae in NGC 5128
Short Name:
J/A+A/574/A109
Date:
21 Oct 2021
Publisher:
CDS
Description:
Planetary nebulae (PNe) are excellent tracers of the common low mass stars through their strong and narrow emission lines. The velocities of large numbers of PNe are excellent tracers of galaxy kinematics. NGC 5128, the nearest large early-type galaxy offers the possibility to gather a large PN sample. Imaging and spectroscopic observations of PNe in NGC 5128 were obtained to find PNe and measure their velocities. Combined with literature data, a large sample of high quality kinematic probes is assembled for dynamical studies in NGC 5128. NTT Imaging was obtained in 15 fields in NGC 5128 over 1 degree with EMMI and [OIII] and off-band filters. Newly detected emission sources, combined with literature PN, were used as input for FLAMES multi-fibre spectroscopy in MEDUSA mode. Spectra of the 4600-5100{AA} region were analysed and velocities were measured based on [OIII]4959,5007{AA} and often H{beta}. The chief results are catalogues of 1118 PN candidates and 1267 spectroscopically confirmed PNe in NGC 5128. The catalogue of PN candidates contains 1060 potential PNe discovered with NTT EMMI imaging and 58 from literature surveys. The spectroscopically confirmed PN catalogue has FLAMES radial velocity and emission line measurements for 1135 PNe, of which 486 are newly confirmed here. An additional 132 PN radial velocities are available from the literature. For 629 PNe observed with FLAMES, H-beta was measured in addition to the [OIII] emission lines. Nine targets show double-lined or more complex profiles (19 components in total), and their possible origin is discussed. FLAMES spectra of 48 globular clusters were also targetted, and 11 had emission lines detected (two with multiple components), but only 3 are PNe likely to belong to the host globular. Conclusions. The total of 1267 confirmed PNe in NGC 5128 with radial velocity measurements, of which 1135 have small velocity errors, is the largest such collection of individual kinematic probes in an early-type galaxy. This PN dataset, as well as the catalogue of 1118 PN candidates, are valuable resources for detailed investigation of the kinematics and stellar population of NGC 5128.
14233. Spectroscopy of QSO pairs
ID:
ivo://CDS.VizieR/J/ApJS/175/29
Title:
Spectroscopy of QSO pairs
Short Name:
J/ApJS/175/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Ly{alpha} forest has opened a new redshift regime for cosmological investigation. At z>2 it provides a unique probe of cosmic geometry and an independent constraint on dark energy that is not subject to standard candle or ruler assumptions. In Paper I of this series on using the Ly{alpha} forest observed in pairs of QSOs for a new application of the Alcock-Paczynski test, we present and discuss the results of a campaign to obtain moderate-resolution spectroscopy (FWHM~2.5{AA}) of the Ly{alpha} forest in pairs of QSOs with small redshift differences ({Delta}z<0.25, z>2.2) and arcminute separations ({Theta}<5'). This data set, composed of seven individual QSOs, 35 pairs, and one triplet, is also well suited for future investigations of the coherence of Ly{alpha} absorbers on ~1Mpc transverse scales and the transverse proximity effect. We note seven revisions for previously published QSO identifications and/or redshifts.
14234. Spectroscopy of quasar binary candidates
ID:
ivo://CDS.VizieR/J/ApJ/678/635
Title:
Spectroscopy of quasar binary candidates
Short Name:
J/ApJ/678/635
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectroscopy of binary quasar candidates, with component separations of 3"<={Delta}{theta}<6", selected from SDSS DR4 using kernel density estimation (KDE). Of our 27 new quasar pair observations, 10 are binary quasars, which doubles the number of known g<21 binaries with 3"<={Delta}{theta}<6" separations. Several of our observed binaries are wide-separation lens candidates that merit additional higher resolution spectroscopy, as well as deep imaging to search for lensing galaxies. Our candidates are initially selected by UV excess (u-g<1), but are otherwise selected irrespective of the relative colors of the quasar pair, and we thus use them to suggest optimal color similarity and photometric redshift approaches for targeting binary quasars or projected quasar pairs. We find that a third or more of all binary quasars have quite dissimilar components on the basis of a typical color similarity criterion ({chi}^2^_color_<~20). From a sample that is complete on proper scales of 23.7h^-1^kpc<R_prop_<29.9h^-1^kpc, we determine the projected quasar correlation function.
14235. Spectroscopy of quiescent gal. in 9 lensing clusters
ID:
ivo://CDS.VizieR/J/ApJ/902/17
Title:
Spectroscopy of quiescent gal. in 9 lensing clusters
Short Name:
J/ApJ/902/17
Date:
03 Mar 2022 11:35:20
Publisher:
CDS
Description:
We measure the central stellar velocity dispersion function for quiescent galaxies in a set of nine northern clusters in the redshift range 0.18<z<0.29 and with strong lensing arcs in Hubble Space Telescope images. The velocity dispersion function links galaxies directly to their dark matter halos. From dense SDSS and MMT/Hectospec spectroscopy, we identify 222-463 spectroscopic members in each cluster. We derive physical properties of cluster members including redshift, D_n_4000, and central stellar velocity dispersion and we include a table of these measurements for 3419 cluster members. We construct the velocity dispersion functions for quiescent galaxies with D_n_4000>1.5 and within R200. The cluster velocity dispersion functions all show excesses at {sigma}>~250km/s compared to the field velocity dispersion function. The velocity dispersion function slope at large velocity dispersion ({sigma}>160km/s) is steeper for more massive clusters, consistent with the trend observed for cluster luminosity functions. The spatial distribution of galaxies with large velocity dispersion at radii larger than R200 further underscores the probable major role of dry mergers in the growth of massive cluster galaxies during cluster assembly.
14236. Spectroscopy of red giants in 12 open clusters
ID:
ivo://CDS.VizieR/J/MNRAS/393/272
Title:
Spectroscopy of red giants in 12 open clusters
Short Name:
J/MNRAS/393/272
Date:
21 Oct 2021
Publisher:
CDS
Description:
Near-infrared spectra of 133 red giant stars from 10 Galactic open clusters and two Galactic globular clusters spanning 2.2dex in metallicity and 11Gyr in age are presented. We combine this sample with 10 clusters from Cole and collaborators (2004MNRAS.347..367C) to investigate the CaII triplet line strengths and their relation to cluster metallicity and position along the red giant branch. We show that characterizing the stellar surface gravity using K_s_-band photometry (relative to the horizontal branch) taken from the Two Micron All-Sky Survey allows for metallicity measurements at least as precise as those derived using V- or I-band data. This has the great advantage that uniform photometry and reliable astrometry are available for a large number of clusters. Using K_s_-band photometry also reduces the effect of differential reddening within a given cluster. We find no significant evidence for age or metallicity effects to the linear CaII triplet-metallicity relationship over the small range in magnitudes studied when homogeneous reference metallicities are used. We derive the first spectroscopic metallicity and new radial velocity estimates for five open clusters: Berkeley 81, Berkeley 99, IC 1311, King 2 and NGC7044. King2 has an anomalous radial velocity compared with the local disc population. We discuss the possibility that it is part of the Monoceros tidal stream.
14237. Spectroscopy of 400 red giants in the Bulge
ID:
ivo://CDS.VizieR/J/A+A/546/A57
Title:
Spectroscopy of 400 red giants in the Bulge
Short Name:
J/A+A/546/A57
Date:
21 Oct 2021
Publisher:
CDS
Description:
The presence of two stellar populations in the Milky Way bulge has been reported recently, based on observations of giant and dwarf stars in the inner an intermediate bulge. We aim at studying the abundances and kinematics of stars in the outer Galactic bulge, thereby providing additional constraints on formation models of the bulge. Spectra of 401 red giant stars in a field at (l,b)=(0,-10) were obtained with the FLAMES-GIRAFFE spectrograph at the VLT. Stars of luminosities down to below the two bulge red clumps are included in the data set. From these spectra we measure general metallicities, abundances of iron and the alpha-elements, and radial velocities of the stars. The abundances are derived from an interpolation and fitting procedure within a grid of COMARCS model atmospheres and spectra. These measurements as well as photometric data are compared to simulations with the Besancon and TRILEGAL models of the Galaxy. We confirm the presence of two populations among our sample stars: i) a metal-rich one at [M/H]~+0.3, comprising about 30% of the sample, with low velocity dispersion and low alpha-abundance, and ii) a metal-poor population at [M/H]~-0.6 with high velocity dispersion and high alpha-abundance. The metallicity difference between the two populations, a systematically and statistically robust figure, is Delta[M/H]=0.87+-0.03. The metal-rich population could be connected to the Galactic bar. We identify this population as the carrier of the double red clump feature. We do not find a significant difference in metallicity or radial velocity between the two red clumps, a small difference in metallicity being probably due to a selection effect and contamination by the metal-poor population. The velocity dispersion agrees well with predictions of the Besancon Galaxy model, but the metallicity of the "thick bulge" model component should be shifted to lower metallicity by 0.2 to 0.3dex to well reproduce the observations. We present evidence that the metallicity distribution function depends on the evolutionary state of the sample stars, suggesting that enhanced mass loss preferentially removes metal-rich stars. We also confirm the decrease of alpha-element over-abundance with increasing metallicity. Conclusions: Our sample is consistent with the existence of two populations, one being a metal-rich bar, the second one being more like a metal-poor classical bulge with larger velocity dispersion.
14238. Spectroscopy of red giants in the LMC bar
ID:
ivo://CDS.VizieR/J/AJ/129/1465
Title:
Spectroscopy of red giants in the LMC bar
Short Name:
J/AJ/129/1465
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report metallicities and radial velocities derived from spectra at the near-infrared calcium triplet for 373 red giants in a 200arcmin^2^ area at the optical center of the LMC bar. These are the first spectroscopic abundance measurements of intermediate-age and old field stars in the high surface brightness heart of the LMC. The metallicity distribution is sharply peaked at the median value [Fe/H]=-0.40, with a small tail of stars extending down to [Fe/H]<=-2.1; 10% of the red giants are observed to have [Fe/H]<=-0.7.
14239. Spectroscopy of Reticulum II
ID:
ivo://CDS.VizieR/J/ApJ/808/95
Title:
Spectroscopy of Reticulum II
Short Name:
J/ApJ/808/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8+/-0.5km/s and a velocity dispersion of 3.3+/-0.7km/s. The mass-to-light ratio of Ret II within its half-light radius is 470+/-210M_{sun}_/L_{sun}_, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83km/s, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3dex in metallicity, with a dispersion of 0.28+/-0.09dex, and we identify several extremely metal-poor stars with [Fe/H]<-3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H]=-2.65+/-0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log_10_(J)=18.8+/-0.6GeV^2^/cm^5^ within 0.2{deg}, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.
14240. Spectroscopy of 300 RGBs in {omega} Cen
ID:
ivo://CDS.VizieR/J/ApJ/731/64
Title:
Spectroscopy of 300 RGBs in {omega} Cen
Short Name:
J/ApJ/731/64
Date:
21 Oct 2021
Publisher:
CDS
Description:
Omega Centauri is no longer the only globular cluster known to contain multiple stellar populations, yet it remains the most puzzling. Due to the extreme way in which the multiple stellar population phenomenon manifests in this cluster, it has been suggested that it may be the remnant of a larger stellar system. In this work, we present a spectroscopic investigation of the stellar populations hosted in the globular cluster {omega} Centauri to shed light on its still puzzling chemical enrichment history. With this aim, we used FLAMES+GIRAFFE@VLT to observe 300 stars distributed along the multimodal red giant branch of this cluster, sampling with good statistics the stellar populations of different metallicities. We determined chemical abundances for Fe, Na, O, and n-capture elements Ba and La. We confirm that {omega} Centauri exhibits large star-to-star variations in iron with [Fe/H] ranging from ~-2.0 to ~-0.7dex. Barium and lanthanum abundances of metal-poor stars are correlated with iron, up to [Fe/H]~-1.5, while they are almost constant (or at least have only a moderate increase) in the more metal-rich populations. There is an extended Na-O anticorrelation for stars with [Fe/H]<~-1.3 while more metal-rich stars are almost all Na-rich. Sodium was found to mildly increase with iron over the entire metallicity range.

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