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Start Over Subject milky way galaxy
71. Catalog of 5 GHz Galactic Plane Sources
ID:
ivo://CDS.VizieR/VIII/20
Title:
Catalog of 5 GHz Galactic Plane Sources
Short Name:
VIII/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is a catalog of 915 sources in the galactic plane between l=190 - 360 - 40 for -2 < b < 2. The l, b pair of galactic coordinates is given in columns 1 and 2 and essentially constitutes the galactic source name. The 1950 equatorial coordinates for each source are given in columns 3 and 4, and values for the peak brightness temperature and flux density are given in columns 5 and 6. The reader should refer to Section 3 of the source reference for information relating to the determination of the flux densities. Column 7 gives an estimate of the source extension in minutes of arc. Extents are given for source in nonconfused regions only. Finally, in column 8 comments on each source are included where appropriate. Identifications with known supernova remnants are included from the compilation of Clark and Caswell (1976MNRAS.174..267C). Identifications with HII regions are based principally on H109alpha recombination-line emission data, which are mostly obtained from Wilson et al. (1970A&A.....6..364W) but with some unpublished Parkes observations included also.
72. Catalog of hypervelocity candidate stars
ID:
ivo://CDS.VizieR/J/AJ/150/77
Title:
Catalog of hypervelocity candidate stars
Short Name:
J/AJ/150/77
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we analyze a sample of metal-rich (>-0.8dex) main sequence stars in the extended solar neighborhood, investigating kinematic outliers from the background population. The data, which are taken from the Sloan Digital Sky Survey, are kinematically profiled as a function of distance from the Galactic plane using full six-dimensional phase space information. Each star is examined in the context of these kinematic profiles and likelihoods are assigned to quantify whether a star matches the underlying profile. Since some of these stars are likely to have been ejected from the disk, we trace back their orbits in order to determine potential ejection radii. We find that objects with low probability (i.e., "outliers") are typically more metal-poor, faster and, most importantly, have a tendency to originate from the inner Galaxy compared to the underlying population. We also compose a sample of stars with velocities exceeding the local escape velocity. Although we do not discount that our sample could be contaminated by objects with spurious proper motions, a number of stars appear to have been ejected from the disk with exceptionally high velocities. Some of these are consistent with being ejected from the spiral arms and hence are a rich resource for further study. Finally we look at objects whose orbits are consistent with them being ejected at high speeds from the Galactic center. Of these objects we find that one, J135855.65+552538.19, is inconsistent with halo, bulge and disk kinematics and could plausibly have been ejected from the Galactic nucleus via a Hills mechanism.
73. Catalog of stellar clusters in the inner Galaxy
ID:
ivo://CDS.VizieR/J/A+A/560/A76
Title:
Catalog of stellar clusters in the inner Galaxy
Short Name:
J/A+A/560/A76
Date:
21 Oct 2021
Publisher:
CDS
Description:
Stars are born within dense clumps of giant molecular clouds, and constitute young stellar agglomerates known as embedded clusters, which only evolve into bound open clusters under special conditions. We statistically study all embedded clusters (ECs) and open clusters (OCs) known so far in the inner Galaxy, in particular investigating their interaction with the surrounding molecular environment and the differences in their evolution.
74. Catalog of X-ray sources in the NARCS
ID:
ivo://CDS.VizieR/J/ApJ/796/105
Title:
Catalog of X-ray sources in the NARCS
Short Name:
J/ApJ/796/105
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 1415 X-ray sources identified in the Norma Arm Region Chandra Survey (NARCS), which covers a 2{deg}x0.8{deg} region in the direction of the Norma spiral arm to a depth of ~20 ks. Of these sources, 1130 are point-like sources detected with >=3{sigma} confidence in at least one of three energy bands (0.5-10, 0.5-2, and 2-10 keV), five have extended emission, and the remainder are detected at low significance. Since most sources have too few counts to permit individual classification, they are divided into five spectral groups defined by their quantile properties. We analyze stacked spectra of X-ray sources within each group, in conjunction with their fluxes, variability, and infrared counterparts, to identify the dominant populations in our survey. We find that ~50% of our sources are foreground sources located within 1-2 kpc, which is consistent with expectations from previous surveys. Approximately 20% of sources are likely located in the proximity of the Scutum-Crux and near Norma arm, while 30% are more distant, in the proximity of the far Norma arm or beyond. We argue that a mixture of magnetic and nonmagnetic cataclysmic variables dominates the Scutum-Crux and near Norma arms, while intermediate polars and high-mass stars (isolated or in binaries) dominate the far Norma arm. We also present the cumulative number count distribution for sources in our survey that are detected in the hard energy band. A population of very hard sources in the vicinity of the far Norma arm and active galactic nuclei dominate the hard X-ray emission down to f_X_~10^-14^ erg/cm^2^/s, but the distribution curve flattens at fainter fluxes. We find good agreement between the observed distribution and predictions based on other surveys.
75. CaT/[Fe/H] calibration for Galactic bulge stars
ID:
ivo://CDS.VizieR/J/A+A/580/A121
Title:
CaT/[Fe/H] calibration for Galactic bulge stars
Short Name:
J/A+A/580/A121
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new calibration of the calcium II triplet equivalent widths versus [Fe/H], constructed upon K giant stars in the Galactic bulge. This calibration will be used to derive iron abundances for the targets of the GIBS survey, and is in general especially well suited for solar and supersolar metallicity giants, which are typical of external massive galaxies. To obtain the calibration, about 150 bulge K giants were observed with the GIRAFFE spectrograph at the VLT with a resolution of R~20000 and at R~6000. In the first case, the spectra allowed us to directly determine the Fe abundances from several unblended Fe lines, deriving what we call here high-resolution [Fe/H] measurements. The low-resolution spectra allowed us to measure equivalent widths of the two strongest lines of the near-infrared calcium II triplet at 8542 and 8662{AA}. By comparing the two measurements, we derived a relation between calcium equivalent widths and [Fe/H] that is linear over the metallicity range probed here, -1<[Fe/H]<+0.7. By adding a small second-order correction based on literature globular cluster data, we derived the unique calibration equation [Fe/H]_CaT_=-3.150+0.432W'+0.006W'^2^, with an rms dispersion of 0.197dex, valid across the whole metallicity range -2.3<[Fe/H]<+0.7.
76. Central Molecular Zone H2CO temperature maps
ID:
ivo://CDS.VizieR/J/A+A/586/A50
Title:
Central Molecular Zone H2CO temperature maps
Short Name:
J/A+A/586/A50
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic center is the closest region in which we can study star formation under extreme physical conditions like those in high-redshift galaxies. We measure the temperature of the dense gas in the Central Molecular Zone (CMZ) and examine what drives it. We have mapped the inner 300pc of the CMZ in the temperature-sensitive J=3-2 para-formaldehyde (p-H_2_CO) transitions. We use the 3_2,1_-2_2,0_/3_0,3_-2_0,2_ line ratio to determine the gas temperature in n~10^4^-10^5^cm^-3^ gas. We produce temperature maps and cubes with 30" and 1km/s resolution and publish all data in FITS form; they can be recovered from digital object identifier doi:10.7910/DVN/27601.
77. Central Molecular Zone in H^13^CO^+^
ID:
ivo://CDS.VizieR/J/PASJ/67/90
Title:
Central Molecular Zone in H^13^CO^+^
Short Name:
J/PASJ/67/90
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a high-resolution wide-field imaging observation of the Central Molecular Zone (CMZ) in H^13^CO^+^ J=1-0 and SiO v=0, J=2-1 emission lines using the 45-m telescope at the Nobeyama Radio Observatory in order to depict the high-density molecular gas mass distribution and explore molecular gas affected by interstellar shocks. By using the clumpfind algorithm we identify 114 molecular clumps in the H^13^CO^+^ data cube.
78. Century Survey Galactic Halo Project. I.
ID:
ivo://CDS.VizieR/J/AJ/126/1362
Title:
Century Survey Galactic Halo Project. I.
Short Name:
J/AJ/126/1362
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (V-R<0.30mag) as probes of the Milky Way halo. The survey strip spans the range of Galactic latitude 35{deg}<b<88{deg}, allowing us to study the nature of populations of stars and their systematic motions as a function of Galactic latitude. One of our primary goals is to use blue horizontal-branch stars to trace potential star streams in the halo, and to test the hierarchical model for the formation of the Galaxy. In this paper we discuss spectroscopy and multipassband photometry for a sample of 764 blue stars in the Century Survey region. Our sample consists predominantly of A- and F-type stars. We describe our techniques for determination of radial velocities, effective temperatures, metallicities, and surface gravities. Based on these measurements, we derive distance estimates by comparison with a set of calibrated isochrones. We devote special attention to the classification of blue horizontal-branch stars, and compare the results obtained from the application of the techniques of Kinman et al. 1994, Cat. <J/AJ/108/1722>, Wilhelm et al. (1999, Cat. <J/AJ/117/2308>), and Clewley et al. (2002MNRAS.337...87C). We identify 55 blue horizontal-branch stars. Our large sample of stars also uncovers a number of unusual objects, including three carbon-enhanced stars, a late B-type star located 0.8kpc above the Galactic plane, and a DZ white dwarf.
79. Cepheid abund.: multiphase results & spatial gradients
ID:
ivo://CDS.VizieR/J/AJ/156/171
Title:
Cepheid abund.: multiphase results & spatial gradients
Short Name:
J/AJ/156/171
Date:
21 Oct 2021
Publisher:
CDS
Description:
Parameters and abundances have been derived for 435 Cepheids based on an analysis of 1127 spectra. Results from five or more phases are available for 52 of the program stars. The latter set of stars span periods between 1.5 and 68 days. The parameters and abundances show excellent consistency across phase. For iron, the average range in the determined abundance is 0.11 from these 52 stars. For 163 stars with more than one phase available the average range is 0.07. The variation in effective temperature tracks well with phase, as does the total broadening velocity. The gravity and microturbulent velocity follow phase, but with less variation and regularity. Abundance gradients have been derived using Gaia DR2 (Cat. I/345) parallax data, as well as Bayesian distance estimates based upon Gaia DR2 from Bailer-Jones et al. (2018, Cat. I/347). The abundance gradient derived for iron is d[Fe/H]/dR=-0.05 dex/kpc, similar to gradients derived in previous studies.
80. Cepheid Period-Wesenheit-Metallicity relation
ID:
ivo://CDS.VizieR/J/A+A/659/A167
Title:
Cepheid Period-Wesenheit-Metallicity relation
Short Name:
J/A+A/659/A167
Date:
23 Mar 2022 15:18:20
Publisher:
CDS
Description:
Classical Cepheids (DCEPs) represent a fundamental tool to calibrate the extragalactic distance scale. However, they are also powerful stellar population tracers, in the context of Galactic studies. The forthcoming Data Release 3 (DR3) of the Gaia mission will allow us to study with unprecedented detail the structure, the dynamics and the chemical properties of the Galactic disc, and in particular of the spiral arms, where most Galactic DCEPs reside. In this paper we aim at quantifying the metallicity dependence of the Galactic DCEPs Period-Wesenheit (PWZ) relation in the Gaia bands. We adopt a sample of 499 DCEPs with metal abundances from high-resolution spectroscopy, in conjunction with Gaia Early Data Release 3 parallaxes and photometry to calibrate a PWZ relation in the Gaia bands. We find a significant metallicity term, of the order of -0.5mag/dex, which is larger than the values measured in the NIR bands by different authors. Our best PWZ relation is W=(-5.988+/-0.018)-(3.176+/-0.044)(logP-1.0)-(0.520+/-0.090)[Fe/H]. We validate our PWZ relations by using the distance to the Large Magellanic Cloud as a benchmark, finding a very good agreement with the geometric distance provided by eclipsing binaries. As an additional test, we evaluate the metallicity gradient of the young Galactic disc, finding -0.0527+/-0.0022dex/kpc, in very good agreement with previous results.