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2111. Galactic infrared bubbles
ID:
ivo://CDS.VizieR/J/PASJ/71/6
Title:
Galactic infrared bubbles
Short Name:
J/PASJ/71/6
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galactic infrared (IR) bubbles, which have shell-like structures in the mid-IR wavelengths, are known to contain massive stars near their centers. Infrared bubbles in inner Galactic regions (|l|<=65{deg}, |b|<=1{deg}) have so far been studied well to understand the massive star formation mechanisms. In this study, we expand the research area to the whole Galactic plane (0{deg}<=l<360{deg}, |b|<=5{deg}), using the AKARI all-sky survey data. We limit our study to large bubbles with angular radii of >1' to reliably identify and characterize them. For the 247 IR bubbles in total, we derived the radii and the covering fractions of the shells, based on the method developed by Y. Hattori et al. (2016PASJ...68...37H). We also created their spectral energy distributions, using the AKARI and Herschel photometric data, and decomposed them with a dust model to obtain the total IR luminosity and the luminosity of each dust component, i.e., polycyclic aromatic hydrocarbons (PAHs), warm dust, and cold dust. As a result, we find that there are systematic differences in the IR properties of the bubbles between the inner and outer Galactic regions. The total IR luminosities are lower in outer Galactic regions, while there is no systematic difference in the range of the shell radii between inner and outer Galactic regions. More IR bubbles tend to be observed as broken bubbles rather than closed ones and the fractional luminosities of the PAH emission are significantly higher in outer Galactic regions. We discuss the implications of these results for the massive stars and the interstellar environments associated with the Galactic IR bubbles.
2112. Galactic massive stars with AstraLux
ID:
ivo://CDS.VizieR/J/A+A/518/A1
Title:
Galactic massive stars with AstraLux
Short Name:
J/A+A/518/A1
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive stars have high-multiplicity fractions, and many of them have still undetected components, thus hampering the study of their properties. I study a sample of massive stars with high angular resolution to better characterize their multiplicity. I observed 138 fields that include at least one massive star with AstraLux, a lucky imaging camera at the 2.2m Calar Alto telescope. I also used observations of 3 of those fields with ACS/HRC on HST to obtain complementary information and to calibrate the AstraLux data. The results were compared with existing information from the Washington Double Star Catalog, Tycho-2, 2MASS, and other literature results.
2113. Galactic midplane Spitzer red sources
ID:
ivo://CDS.VizieR/J/AJ/136/2413
Title:
Galactic midplane Spitzer red sources
Short Name:
J/AJ/136/2413
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a highly reliable flux-limited census of 18949 point sources in the Galactic midplane that have intrinsically red mid-infrared colors. These sources were selected from the Spitzer Space Telescope Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) I and II surveys of 274{deg}^2^ of the Galactic midplane, and consist mostly of high- and intermediate-mass young stellar objects (YSOs) and asymptotic giant branch (AGB) stars. The selection criteria were carefully chosen to minimize the effects of position-dependent sensitivity, saturation, and confusion. The distribution of sources on the sky and their location in the Infrared Array Camera and the Multiband Image Photometer for Spitzer 24um color-magnitude and color-color space are presented. Using this large sample, we find that YSOs and AGB stars can be mostly separated by simple color-magnitude selection criteria into approximately 50%-70% of YSOs and 30%-50% of AGB stars. Planetary nebulae and background galaxies together represent at most 2%-3% of all the red sources. 1004 red sources in the GLIMPSE II region, mostly AGB stars with high mass-loss rates, show significant (>=0.3mag) variability at 4.5 and/or 8.0um. With over 11,000 likely YSOs and over 7000 likely AGB stars, this is to date the largest uniform census of AGB stars and high- and intermediate-mass YSOs in the Milky Way Galaxy.
2114. GALACTICNUCLEUS IV. JHKs imaging survey
ID:
ivo://CDS.VizieR/J/A+A/653/A133
Title:
GALACTICNUCLEUS IV. JHKs imaging survey
Short Name:
J/A+A/653/A133
Date:
10 Mar 2022 11:26:04
Publisher:
CDS
Description:
The extreme extinction (A_V_~30mag) and its variation on arc-second scales towards the Galactic centre hamper the study of its stars. Their analysis is restricted to the near infrared (NIR) regime, where the extinction curve can be approximated by a broken power law for the JHKs bands. Therefore, correcting for extinction at these wavelengths is fundamental to analyse the structure and stellar population of the central regions of our Galaxy. We aim at: (1) Discussing different strategies to de-redden the photometry and checking the usefulness of extinction maps to deal with variable stars. (2) Building and making publicly available extinction maps for the NIR bands JHKs. (3) Creating a de-reddened catalogue of the GALACTICNUCLEUS (GNS) survey, identifying foreground stars. (4) Performing a preliminary analysis of the de-reddened $K_s$ luminosity functions (KLFs). We use photometry from the GNS survey to create extinction maps for the whole catalogue. We take red clump (RC) and red giant stars of similar brightness as a reference to build the maps, and de-redden the GNS photometry. We discuss the limitations of the process and analyse non-linear effects of the de-reddening. We create high resolution (~3'') extinction maps with low statistical and systematics uncertainties (<~5%), and compute average extinctions for each of the regions covered by the GNS. We check that our maps effectively correct the differential extinction reducing the spread of the RC features by a factor of ~2. We assess the validity of the broken power law approach computing two equivalent extinction maps A_H_ using either JH and HKs photometry for the same reference stars, and obtain compatible average extinctions within the uncertainties. Finally, we analyse de-reddened KLFs for different line-of-sights and find that the regions belonging to the NSD contain a homogeneous stellar population that is significantly different from the one in the innermost bulge regions.
2115. GALACTICNUCLEUS: JHKs imaging survey
ID:
ivo://CDS.VizieR/J/A+A/610/A83
Title:
GALACTICNUCLEUS: JHKs imaging survey
Short Name:
J/A+A/610/A83
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic Centre is of fundamental astrophysical interest, but existing near-infrared surveys fall short covering it adequately, either in terms of angular resolution, multi-wavelength coverage, or both. Here we introduce the GALACTICNUCLEUS survey, a JHKs imaging survey of the centre of the Milky Way with a 0.2" angular resolution. The purpose of this paper is to present the observations of Field 1 of our survey, centred approximately on SgrA* with an approximate size of 7.95'x3.43'. We describe the observational set-up and data reduction pipeline and discuss the quality of the data. Finally, we present the analysis of the data. The data were acquired with the near-infrared camera HAWK-I (High Acuity Wide field K-band Imager) at the ESO VLT (Very Large Telescope). Short readout times in combination with the speckle holography algorithm allowed us to produce final images with a stable, Gaussian PSF (point spread function) of 0.2" FWHM (full width at half maximum). Astrometric calibration is achieved via the VVV (VISTA Variables in the Via Lactea) survey and photometric calibration is based on the SIRIUS/IRSF (Infrared Survey Facility telescope) survey. The quality of the data is assessed by comparison between observations of the same field with different detectors of HAWK-I and at different times. We reach 5{sigma} uncertainties are less than 0.05" at J<=20, H<=17, and Ks<=16. We can distinguish five stellar populations in the colour-magnitude diagrams; three of them appear to belong to foreground spiral arms, and the other two correspond to high- and low-extinction star groups at the Galactic Centre. We use our data to analyse the near-infrared extinction curve and find some evidence for a possible difference between the extinction index between J-H and H-Ks. However, we conclude that it can be described very well by a power law with an index of JHKs=2.30+.-0.08. We do not find any evidence that this index depends on the position along the line of sight, or on the absolute value of the extinction. We produce extinction maps that show the clumpiness of the ISM (interstellar medium) at the Galactic Centre. Finally, we estimate that the majority of the stars have solar or super-solar metallicity by comparing our extinction-corrected colour-magnitude diagrams with isochrones with different metallicities and a synthetic stellar model with a constant star formation.
2116. GALACTICNUCLEUS JHKs imaging survey. II.
ID:
ivo://CDS.VizieR/J/A+A/631/A20
Title:
GALACTICNUCLEUS JHKs imaging survey. II.
Short Name:
J/A+A/631/A20
Date:
21 Oct 2021
Publisher:
CDS
Description:
The high extinction and extreme source crowding of the central regions of the Milky Way are serious obstacles to the study of the structure and stellar population of the Galactic centre (GC). Surveys that cover the GC region (2MASS, UKIDSS, VVV, SIRIUS) do not have the necessary high angular resolution. Therefore, a high angular resolution survey in the near infrared is crucial to improve the state of the art. Here, we present the GALACTICNUCLEUS catalogue, a near infrared JHKs high angular resolution (0.2") survey of the nuclear bulge of the Milky Way. We explain in detail the data reduction, data analysis, calibration, and uncertainty estimation of the GALACTICNUCLEUS survey. We assess the data quality comparing our results with previous surveys. We obtained accurate JHKs photometry ~3.3x10^6^ stars in the GC detecting around 20% in J, 65% in H and 90% in Ks. The survey covers a total area of ~0.3 square degrees, which corresponds to ~6000pc^2^. The GALACTICNUCLEUS survey reaches 5 sigma detections for J~22mag, H~21mag and Ks~21mag. The uncertainties are below 0.05mag at J~21mag, H~19mag and Ks~18mag. The zero point systematic uncertainty is <~0.04mag in all three bands. We present colour-magnitude diagrams for the different regions covered by the survey.
2117. Galactic O star catalog
ID:
ivo://CDS.VizieR/V/116
Title:
Galactic O star catalog
Short Name:
V/116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have produced a catalog of 378 Galactic O stars with accurate spectral classifications that is complete for V<8 but includes many fainter stars. The catalog provides cross-identifications with other sources; coordinates (obtained in most cases from Tycho-2 data); astrometric distances for 24 of the nearest stars; optical (Tycho-2, Johnson, and Stroemgren) and NIR photometry; group membership, runaway character, and multiplicity information; and a Web-based version with links to on-line services.
2118. Galactic O-type Stars
ID:
ivo://CDS.VizieR/II/82
Title:
Galactic O-type Stars
Short Name:
II/82
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog is a compilation from the literature of all O-type stars for which spectral types, luminosity classes, and UBV photometry exist. The catalog contains 765 stars, for each of which designation (HD, DM, etc.), spectral type, V, B-V, absolute visual magnitude, absolute bolometric magnitude, cluster membership, distance, galactic coordinates, and source references are given. In addition, the authors have included derived values of absolute visual and bolometric magnitudes, and distances. The Catalog of Galactic O-Type Stars (Garmany, Conti and Chiosi 1982) is a compilation from the literature of all O-type stars for which spectral types, luminosity classes and UBV photometry exist. Most of the entries come from Cruz-Gonzalez, et al. (1974) and Humphreys (1978), with additional stars from Garrison and Kormendy (1976), Garrison, Hiltner and Schild (1977), Garrison and Schild (1979), Feinstein, Marraco and Muzzio (1973), Feinstein, Marraco and Forte (1976), and Moffat, FitzGerald and Jackson (1979).
2119. Galactic outer disk: a field toward Tombaugh 1
ID:
ivo://CDS.VizieR/J/AJ/153/99
Title:
Galactic outer disk: a field toward Tombaugh 1
Short Name:
J/AJ/153/99
Date:
21 Oct 2021
Publisher:
CDS
Description:
We employ optical photometry and high-resolution spectroscopy to study a field toward the open cluster Tombaugh 1, where we identify a complex population mixture that we describe in terms of young and old Galactic thin disks. Of particular interest is the spatial distribution of the young population, which consists of dwarfs with spectral types as early as B6 and is distributed in a blue plume feature in the color-magnitude diagram. For the first time, we confirm spectroscopically that most of these stars are early-type stars and not blue stragglers or halo/thick-disk subdwarfs. Moreover, they are not evenly distributed along the line of sight but crowd at heliocentric distances between 6.6 and 8.2 kpc. We compare these results with present-day understanding of the spiral structure of the Galaxy and suggest that they trace the outer arm. This range of distances challenges current Galactic models adopting a disk cutoff at 14 kpc from the Galactic center. The young dwarfs overlap in space with an older component, which is identified as an old Galactic thin disk. Both young and old populations are confined in space since the disk is warped at the latitude and longitude of Tombaugh 1. The main effects of the warp are that the line of sight intersects the disk and entirely crosses it at the outer arm distance and that there are no traces of the closer Perseus arm, which would then be either unimportant in this sector or located much closer to the formal Galactic plane. Finally, we analyze a group of giant stars, which turn out to be located at very different distances and to possess very different chemical properties, with no obvious relation to the other populations.
2120. Galactic planetary nebulae at 24{mu}m
ID:
ivo://CDS.VizieR/J/MNRAS/410/2257
Title:
Galactic planetary nebulae at 24{mu}m
Short Name:
J/MNRAS/410/2257
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained 24{mu}m imaging, profiles and fluxes for 224 planetary nebulae (PNe) lying within the limits of the Galactic survey undertaken with the Multiband Imaging Photometer for Spitzer (MIPSGAL). It is noted that most of the PNe having extended 24{mu}m emission also possess circular morphologies, suggesting that the emission derives from cool grains located within the Asymptotic Giant Branch (AGB) mass-loss regimes. Certain of these haloes are found to have a surface brightness fall-off which may be consistent with secularly invariant mass loss within the PNe progenitors. By contrast, the 8.0{mu}m envelopes are detected out to smaller distances from the nuclei, and have a steeper rate of surface brightness fall-off; a phenomenon which may arise from changes in the excitation of polycyclic aromatic hydrocarbons (PAHs) within external photo-dissociation regimes (PDRs). Our 24{mu}m fluxes are compared to those in previously published studies, and this appears to indicate that many of the prior fluxes have been underestimated; a disparity may imply that previous aperture sizes were too small. We have also combined our 24{mu}m fluxes with measures at shorter mid-infrared (MIR) wavelengths, taken with the Infrared Array Camera (IRAC). These are used to investigate the positioning of PNe within the IRAC-MIPSGAL colour planes. The [8.0]-[24] and [5.8]-[24] colours are found to be large, and extend over the respective ranges 3.4-8.7mag, and 5.4-10.3mag; indices which are only explainable where a broad range of mechanisms contribute to the fluxes, including PAH bands, cool dust continua and a variety of ionic transitions. These and other components also affect the morphologies of the sources, and lead to wavelength-dependent changes in the widths of the profiles.