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Start Over Subject milky way galaxy Validation Level 2
241. GES: pre-main-sequence clusters [Fe/H]
ID:
ivo://CDS.VizieR/J/A+A/601/A70
Title:
GES: pre-main-sequence clusters [Fe/H]
Short Name:
J/A+A/601/A70
Date:
21 Oct 2021
Publisher:
CDS
Description:
The radial metallicity distribution in the Galactic thin disc represents a crucial constraint for modelling disc formation and evolution. Open clusters allow us to derive both the radial metallicity distribution and its evolution over time. In this paper we perform the first investigation of the present-day radial metallicity distribution based on [Fe/H] determinations in late type members of pre-main-sequence clusters. Because of their youth, these clusters are therefore essential for tracing the current inter-stellar medium metallicity. We used the products of the Gaia-ESO Survey analysis of 12 young regions (age<100Myr), covering Galactocentric distances from 6.67 to 8.70kpc. For the first time, we derived the metal content of star forming regions farther than 500pc from the Sun. Median metallicities were determined through samples of reliable cluster members. For ten clusters the membership analysis is discussed in the present paper, while for other two clusters (Chamaeleon I and Gamma Velorum) we adopted the members identified in our previous works. All the pre-main-sequence clusters considered in this paper have close-to-solar or slightly sub-solar metallicities. The radial metallicity distribution traced by these clusters is almost flat, with the innermost star forming regions having [Fe/H] values that are 0.10-0.15dex lower than the majority of the older clusters located at similar Galactocentric radii. This homogeneous study of the present-day radial metallicity distribution in the Galactic thin disc favours models that predict a flattening of the radial gradient over time. On the other hand, the decrease of the average [Fe/H] at young ages is not easily explained by the models. Our results reveal a complex interplay of several processes (e.g. star formation activity, initial mass function, supernova yields, gas flows) that controlled the recent evolution of the Milky Way.
242. 90GHz obs. of high-mass star-forming regions
ID:
ivo://CDS.VizieR/J/ApJ/777/157
Title:
90GHz obs. of high-mass star-forming regions
Short Name:
J/ApJ/777/157
Date:
21 Oct 2021
Publisher:
CDS
Description:
The chemical changes of high-mass star-forming regions provide a potential method for classifying their evolutionary stages and, ultimately, ages. In this study, we search for correlations between molecular abundances and the evolutionary stages of dense molecular clumps associated with high-mass star formation. We use the molecular line maps from Year 1 of the Millimetre Astronomy Legacy Team 90GHz (MALT90) Survey. The survey mapped several hundred individual star-forming clumps chosen from the ATLASGAL survey to span the complete range of evolution, from prestellar to protostellar to H II regions. The evolutionary stage of each clump is classified using the Spitzer GLIMPSE/MIPSGAL mid-IR surveys. Where possible, we determine the dust temperatures and H_2_ column densities for each clump from Herschel/Hi-GAL continuum data. From MALT90 data, we measure the integrated intensities of the N_2_H^+^, HCO^+^, HCN and HNC(1-0) lines, and derive the column densities and abundances of N_2_H^+^ and HCO^+^. The Herschel dust temperatures increase as a function of the IR-based Spitzer evolutionary classification scheme, with the youngest clumps being the coldest, which gives confidence that this classification method provides a reliable way to assign evolutionary stages to clumps. Both N_2_H^+^ and HCO^+^ abundances increase as a function of evolutionary stage, whereas the N_2_H^+^(1-0) to HCO^+^(1-0) integrated intensity ratios show no discernable trend. The HCN(1-0) to HNC(1-0) integrated intensity ratios show marginal evidence of an increase as the clumps evolve.
243. 86GHz SiO maser survey in the Inner Galaxy
ID:
ivo://CDS.VizieR/J/A+A/418/103
Title:
86GHz SiO maser survey in the Inner Galaxy
Short Name:
J/A+A/418/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a compilation and study of DENIS, 2MASS, ISOGAL, MSX and IRAS 1-25 microns photometry for a sample of 441 late-type stars in the inner Galaxy, which we previously searched for 86GHz SiO maser emission (Messineo et al., 2002, Cat. <J/A+A/393/115>). The comparison of the DENIS and 2MASS J and Ks magnitudes shows that most of the SiO targets are indeed variable stars. The MSX colours and the IRAS [12]-[25] colour of our SiO targets are consistent with those of Mira type stars with dust silicate feature at 9.7 microns feature in emission, indicating only a moderate mass-loss rate.
244. Giant molecular clouds in the 4th Galactic quadrant
ID:
ivo://CDS.VizieR/J/ApJS/212/2
Title:
Giant molecular clouds in the 4th Galactic quadrant
Short Name:
J/ApJS/212/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Columbia University-Universidad de Chile CO Survey of the southern Milky Way is used to separate the CO(1-0) emission of the fourth Galactic quadrant within the solar circle into its dominant components, giant molecular clouds (GMCs). After the subtraction of an axisymmetric model of the CO background emission in the inner southern Galaxy, 92 GMCs are identified, and for 87 of them the twofold distance ambiguity is solved. Their total molecular mass is M(H_2_)=1.14+/-0.05x10^8^M_{sun}_, accounting for around 40% of the molecular mass estimated from an axisymmetric analysis of the H_2_ volume density in the Galactic disk, M(H_2_)_disk_=3.03x10^8^M_{sun}_. The large-scale spiral structure in the southern Galaxy, within the solar circle, is traced by the GMCs in our catalog; three spiral arm segments, the Centaurus, Norma, and 3 kpc expanding arm, are analyzed. After fitting a logarithmic spiral arm model to the arms, tangent directions at 310{deg}, 330{deg}, and 338{deg}, respectively, are found, consistent with previous values from the literature. A complete CS(2-1) survey toward IRAS point-like sources with far-IR colors characteristic of ultracompact H II regions is used to estimate the massive star formation rate per unit H_2_ mass (MSFR) and the massive star formation efficiency ({epsilon}) for GMCs. The average MSFR for GMCs is 0.41+/-0.06L_{sun}_/M_{sun}_, and for the most massive clouds in the Norma arm it is 0.58+/-0.09L_{sun}_/M_{sun}_. Massive star formation efficiencies of GMCs are, on average, 3% of their available molecular mass.
245. Giant molecular filaments in the Milky Way
ID:
ivo://CDS.VizieR/J/A+A/590/A131
Title:
Giant molecular filaments in the Milky Way
Short Name:
J/A+A/590/A131
Date:
21 Oct 2021
Publisher:
CDS
Description:
Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to the large-scale, Galactic spiral arm structure. Addressing the nature of these giant molecular filaments (GMFs) requires a census of their occurrence and properties. We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. Methods. We identify GMFs based on their dust extinction signatures in the near- and mid-infrared and the velocity structure probed by ^13^CO line emission. We use the ^13^CO line emission and ATLASGAL dust emission data to estimate the total and dense gas masses of the GMFs. We combine our sample with an earlier sample from literature and study the Galactic environment of the GMFs.
246. GIRAFFE Inner Bulge Survey (GIBS). I.
ID:
ivo://CDS.VizieR/J/A+A/562/A66
Title:
GIRAFFE Inner Bulge Survey (GIBS). I.
Short Name:
J/A+A/562/A66
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic bulge is a massive, old component of the Milky Way. It is known to host a bar, and it has recently been demonstrated to have a pronounced boxy/peanut structure in its outer region. Several independent studies suggest the presence of more than one stellar populations in the bulge, with different origins and a relative fraction changing across the bulge area. This is the first of a series of papers presenting the results of the Giraffe Inner Bulge Survey, carried out at the ESO-VLT with the multifibre spectrograph FLAMES. Spectra of ~5000 red clump giants in 24 bulge fields have been obtained at resolution R=6500, in the infrared Calcium triplet wavelength region at ~8500{AA}. They are used to derive radial velocities and metallicities, based on new calibration specifically devised for this project. Radial velocities for another ~1200 bulge red clump giants, obtained from similar archive data, have been added to the sample. Higher resolution spectra have been obtained for ~450 additional stars at latitude b=-3.5, with the aim of investigating chemical abundance patterns variations with longitude, across the inner bulge. In total we present here radial velocities for 6494 red clump stars. We present here the target selection criteria, observing strategy and the catalogue with radial velocity measurements for all the target stars.
247. GIRAFFE Inner Bulge Survey (GIBS). II.
ID:
ivo://CDS.VizieR/J/A+A/584/A46
Title:
GIRAFFE Inner Bulge Survey (GIBS). II.
Short Name:
J/A+A/584/A46
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate metallicity and {alpha}-element abundance gradients along a Galactic longitude strip, at latitude b~-4{deg}, with the aim of providing observational constraints for the structure and origin of the Milky Way bulge. High-resolution (R~22500) spectra for 400 Kgiants, in four fields within -4.8{deg}<~b<~-3.4{deg} and -10{deg}<~l<~+10{deg}, were obtained within the GIRAFFE Inner Bulge Survey (GIBS) project. To this sample we added another ~400 stars in Baade's Window at (l,b)=(1{deg},-4{deg}), observed with the identical instrumental configuration: FLAMES GIRAFFE in Medusa mode with HR13 setup. All target stars lie within the red clump of the bulge colour-magnitude diagram, thus minimising contamination from the disc or halo stars. The spectroscopic stellar surface parameters were derived with an automatic method based on the GALA code, while the [Ca/Fe] and [Mg/Fe] abundances as a function of [Fe/H] were derived through a comparison with the synthetic spectra using MOOG. We constructed the metallicity distributions for the entire sample, and for each field individually, in order to investigate the presence of gradients or field-to-field variations in the shape of the distributions.
248. Gjoll stream stars & detailed abund. of 4 members
ID:
ivo://CDS.VizieR/J/ApJ/901/23
Title:
Gjoll stream stars & detailed abund. of 4 members
Short Name:
J/ApJ/901/23
Date:
15 Feb 2022 14:07:06
Publisher:
CDS
Description:
Recent analysis of the second data release of Gaia has revealed a number of new stellar streams surrounding the Milky Way. It has been suggested that one of these streams, Gjoll, is associated with the globular cluster NGC 3201, but thus far the association has only been based on kinematics of the stream stars. In this work we identify five likely stream members in the Gaia data that are bright enough for high-resolution spectroscopic follow-up with the Harlan J. Smith telescope at McDonald Observatory. One star is ruled out as a member based on its radial velocity. Abundance analysis of the remaining four kinematic members reveals a good chemical match to NGC 3201 for two of the stars, driven by their similar Al and {alpha}-element abundances. Of the remaining two, one shows no chemical similarity to NGC 3201 and is likely an unassociated Milky Way halo field star, while the other exhibits a similar Al abundance but has somewhat lower {alpha}-element abundances. The chemical tagging of stars in the Gjoll stream to NGC3201 confirms this association and provides direct proof of the hierarchical formation of the Milky Way.
249. GLIMPSE Source Catalog (I + II + 3D)
ID:
ivo://CDS.VizieR/II/293
Title:
GLIMPSE Source Catalog (I + II + 3D)
Short Name:
II/293
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE), is a survey of Galactic Plane central parts made with the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope (SST). It covers approximately 220 square degrees, between galactic longitudes +/-65{deg} and +/-1{deg} in galactic latitude (up to 4.2{deg} in the central parts). The four IRAC bands are centered at approximately 3.6, 4.5, 5.8 and 8.0{mu}m. The GLIMPSE combines the 3 surveys: * GLIMPSE-I covers the longitude ranges |l|=10--65{deg} and the latitude range |b|<=1{deg} (Benjamin et al. 2003PASP..115..953B) * GLIMPSE-II covers the longitude range of |l|<=10{deg}, and a latitude range |b|<=1{deg} from |l|=5--10, |b|<=1.5 for |l|=2--5, and |b|<=2{deg} for |l|<=2. GLIMPSE-II coverage excludes the Galactic center region |l|<=1, |b|<=0.75 observed by the GALCEN GO program (PID=3677). * GLIMPSE-3D adds vertical extensions up to |b|=4.2{deg} near the galactic center, and up to |b|=3{deg} in selected other parts of the Galaxy (+/-10, 18.5, 25, 30, and -15 (345){deg}). GLIMPSE-II had two-epoch coverage for a total of three visits on the sky. The observations consisted of two 1.2 second integrations at each position in the first epoch of data taking (September 2005) and a single 1.2 second integration at each position six months later (April 2006). The highly reliable v2.0 GLIMPSEII Catalog (v2.0_GLMIIC) consists of point sources that are detected at least twice in one band and at least once in an adjacent band and a S/N > 5 cut for the band with the two detections. There are also faint and bright flux limits on the Catalog entries. The more complete v2.0 Archive (v2.0_GLMIIA) has less stringent criteria, namely two detections in any bands, those detections having a S/N > 5. The IRAC data were bandmerged with the 2MASS All-Sky Point Source Catalog. See the GLIMPSEII v2.0 Data Products & Data Delivery document for more details. The catalog available from CDS merges the 3 surveys GLIMPSE-I (v2.0), GLIMPSE-II (v2.0), and GLIMPSE-3D; Catalog and Archive records are also merged here. In the regions of overlap between the 3 surveys (e.g. longitude around 10{deg}) preference was given to (1) GLIMPSE-II, as recommended in the GLIMPSE documents of May 2007 (glimpse1_v2.0.pdf) and April 2008 (glimpse2-v2.0.pdf); (2) GLIMPSE-I, and (3) GLIMPSE-3D sources. Sources from different surveys were merged if their position is closer than 0.1arcsec. Documents and a document describing in detail the point source photometry steps, see http://www.astro.wisc.edu/glimpse/docs.html
250. Globular and open clusters observed by SDSS/SEGUE
ID:
ivo://CDS.VizieR/J/AJ/151/7
Title:
Globular and open clusters observed by SDSS/SEGUE
Short Name:
J/AJ/151/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present griz observations for the clusters M92, M13 and NGC 6791 and gr photometry for M71, Be 29 and NGC 7789. In addition we present new membership identifications for all these clusters, which have been observed spectroscopically as calibrators for the Sloan Digital Sky Survey (SDSS)/SEGUE survey; this paper focuses in particular on the red giant branch stars in the clusters. In a number of cases, these giants were too bright to be observed in the normal SDSS survey operations, and we describe the procedure used to obtain spectra for these stars. For M71, we also present a new variable reddening map and a new fiducial for the gr giant branch. For NGC 7789, we derived a transformation from T_eff_ to g-r for giants of near solar abundance, using IRFM T_eff_ measures of stars with good ugriz and 2MASS photometry and SEGUE spectra. The result of our analysis is a robust list of known cluster members with correctly dereddened and (if needed) transformed gr photometry for crucial calibration efforts for SDSS and SEGUE.