- ID:
- ivo://CDS.VizieR/J/A+A/649/A83
- Title:
- Milky Way nuclear disk KMOS survey
- Short Name:
- J/A+A/649/A83
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In the central few degrees of the bulge of the Milky Way there is a flattened structure of gas, dust, and stars, known as the central molecular zone, that is similar to nuclear disks in other galaxies. As a result of extreme foreground extinction, we possess only sparse information about the (mostly old) stellar population of the nuclear disk. In this work we present our KMOS spectroscopic survey of the stars in the nuclear disk reaching the old populations. To obtain an unbiased data set, we sampled stars in the full extinction range along each line of sight. We also observed reference fields in neighboring regions of the Galactic bulge. We describe the design and execution of the survey and present first results. We obtain spectra and five spectral indices of 3113 stars with a median S/N of 67 and measure radial velocities for 3051 stars. Of those, 2735 sources have sufficient S/N to estimate temperatures and metallicities from indices. We derive metallicities using the CO 2-0 and Na I K-band spectral features, where we derive our own empirical calibration using metallicities obtained with higher-resolution observations.We use 183 giant stars for calibration spanning in metallicity from -2.5 to 0.6dex and covering temperatures of up to 5500K. The derived index based metallicities deviate from the calibration values with a scatter of 0.32dex. The internal uncertainty of our metallicities is likely smaller. We use these metallicity measurements, together with the CO index, to derive effective temperatures using literature relations. We publish the catalog in this paper. Our data set complements Galactic surveys such as Gaia and APOGEE for the inner 200pc radius of the Milky Way, which is not readily accessible by those surveys owing to extinction. We will use the derived properties in future papers for further analysis of the nuclear disk.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/566/A47
- Title:
- Milky Way nuclear star cluster extinction map
- Short Name:
- J/A+A/566/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although the Milky Way Nuclear Star Cluster (MWNSC) was discovered more than four decades ago, several of its key properties have not been determined unambiguously up to now because of the strong and spatially highly variable interstellar extinction toward the Galactic centre. In this paper we aim at determining the shape, size, and luminosity/mass of the MWNSC.In order to investigate the properties of the MWNSC, we use Spitzer/IRAC images at 3.6 and 4.5{mu}m, where interstellar extinction is at a minimum but the overall emission is still dominated by stars. We correct the 4.5{mu}m image for PAH emission with the help of the IRAC 8.0{mu}m map and for extinction with the help of a [3.6-4.5] colour map. Finally, we investigate the symmetry of the nuclear cluster and fit it with Sersic, Moffat, and King models. We present an extinction map for the central ~300x200pc^2^ of the Milky Way, as well as a PAH-emission and extinction corrected image of the stellar emission, with a resolution of about 0.20pc. We find that the MWNSC appears in projection intrinsically point-symmetric, that it is significantly flattened, with its major axis aligned along the Galactic Plane, and that it is centred on the black hole, Sagittarius A*. Its density follows the well known approximate {rho}{prop.to}r^-2^-law at distances of a few parsecs from Sagittarius A*, but becomes as steep as about {rho}{prop.to}r^-3^ at projected radii around 5pc. We derive a half light radius of 4.2+/-0.4pc, a total luminosity of L_MWNSC,4.5{mu}m_=4.1+/-0.4x10^7^L_{sun}_, and a mass of M_MWNSC_=2.1+/-0.4x10^7^M_{sun}_. The overall properties of the MWNSC agree well with the ones of its extragalactic counterparts, which underlines its role as a template for these objects. Its flattening agrees well with its previously established rotation parallel to Galactic rotation and suggests that it has formed by accretion of material that fell in preferentially along the Galactic Plane. Our findings support the in situ growth scenario for nuclear clusters and emphasize the need to increase the complexity of theoretical models for their formation and for the interaction between their stars and the central black hole in order to include rotation, axisymmetry, and growth in recurrent episodes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/488/1141
- Title:
- Milky Way Project DR2 bubbles & bow shocks
- Short Name:
- J/MNRAS/488/1141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Citizen science has helped astronomers comb through large data sets to identify patterns and objects that are not easily found through automated processes. The Milky Way Project (MWP), a citizen science initiative on the Zooniverse platform, presents internet users with infrared (IR) images from Spitzer Space Telescope Galactic plane surveys. MWP volunteers make classification drawings on the images to identify targeted classes of astronomical objects. We present the MWP second data release (DR2) and an updated data reduction pipeline written in Python. We aggregate 3 million classifications made by MWP volunteers during the years 2012-2017 to produce the DR2 catalogue, which contains 2600 IR bubbles and 599 candidate bow-shock driving stars. The reliability of bubble identifications, as assessed by comparison to visual identifications by trained experts and scoring by a machine-learning algorithm, is found to be a significant improvement over DR1. We assess the reliability of IR bow shocks via comparison to expert identifications and the colours of candidate bow-shock driving stars in the 2MASS point-source catalogue. We hence identify highly-reliable subsets of 1394 DR2 bubbles and 453 bow-shock driving stars. Uncertainties on object coordinates and bubble size/shape parameters are included in the DR2 catalog. Compared with DR1, the DR2 bubbles catalogue provides more accurate shapes and sizes. The DR2 catalogue identifies 311 new bow shock driving star candidates, including three associated with the giant HII regions NGC 3603 and RCW 49.
- ID:
- ivo://CDS.VizieR/J/ApJS/161/361
- Title:
- Millimeter continuum survey for protoclusters
- Short Name:
- J/ApJS/161/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our search for the earliest stages of massive star formation turned up 12 massive pre-protocluster candidates plus a few protoclusters. For this search, we selected 47 FIR-bright IRAS sources in the outer Galaxy. We mapped regions of several square arcminutes around the IRAS source in the millimeter continuum in order to find massive cold cloud cores possibly being in a very early stage of massive star formation. Masses and densities are derived for the 128 molecular cloud cores found in the obtained maps.
- ID:
- ivo://CDS.VizieR/J/A+A/390/501
- Title:
- Millimetre observations of carbon stars. I.
- Short Name:
- J/A+A/390/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Millimetre observations of IRAS selected red carbon stars are presented. About 260 stars have been observed with SEST and IRAM in the CO (1-0) and CO (2-1) lines and partially in HCN (1-0) and SiO (3-2). An overall detection rate, in at least one line, of about 80% is achieved. The survey represents the second largest survey for AGB stars, and the largest ever for carbon stars. Two new detections in SiO (3-2) in carbon stars are reported. When available, the SiO/HCN and HCN/CO(1-0) line ratios are consistent with the ratios expected for carbon stars.
- ID:
- ivo://CDS.VizieR/J/A+A/390/511
- Title:
- Millimetre observations of carbon stars. II.
- Short Name:
- J/A+A/390/511
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust- and gas mass loss rates and distances are determined for a sample of about 330 infra-red carbon stars that probe a distance up to about 5.5kpc. The dependence of the dust- and gas mass loss rates, and the expansion velocity upon galactic longitude (l) are studied. It is found that the expansion velocity significantly depends on l, but that the absolute bolometric magnitude, the dust mass loss rate and the gas-to-dust ratio depend on l marginally, if at all, and the gas mass loss rate does not depend on l. Beyond the solar circle, the expansion velocity (as well as the luminosity, dust-to-gas ratio, dust mass loss rate) is lower than inside the solar circle, as expected from the overall gradient in metallicity content of the Galaxy. Combining the average expansion velocity inside and beyond the solar circle with the theoretically predicted relation between expansion velocity and gas-to-dust ratio, we find that the metallicity gradient in the solar neighbourhood is about -0.034dex/kpc, well within the quoted range of values in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/641/389
- Title:
- Millimetric observations of IRDC cores
- Short Name:
- J/ApJ/641/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared dark clouds (IRDCs) are dense molecular clouds seen as extinction features against the bright mid-infrared Galactic background. Millimeter continuum maps toward 38 IRDCs reveal extended cold dust emission to be associated with each of the IRDCs. IRDCs range in morphology from filamentary to compact and have masses of 120 to 16000M_{sun}_, with a median mass of 940M_{sun}_. Each IRDC contains at least one compact (0.5pc) dust core and most show multiple cores. We find 140 cold millimeter cores unassociated with MSX 8{mu}m emission.
- ID:
- ivo://CDS.VizieR/J/AJ/149/64
- Title:
- MIPSGAL 24{mu}m point source catalog
- Short Name:
- J/AJ/149/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this contribution, we describe the applied methods to construct a 24{mu}m based point source catalog derived from the image data of the MIPSGAL 24{mu}m Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933818 sources, with a total of 1353228 in the full archive catalog. The source tables include positional and photometric information derived from the 24{mu}m images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1' angular resolution that describe the varying background levels over the MIPSGAL field and the ability to extract sources of a given magnitude from this background. The completeness decay cubes are included in the set of data products. We present the results of our efforts to verify the astrometric and photometric calibration of the catalog, and present several analyses of minor anomalies in these measurements to justify adopted mitigation strategies.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/212
- Title:
- MIPS sources near the South Ecliptic Pole
- Short Name:
- J/ApJS/191/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged an 11.5deg^2^ region of sky toward the South Ecliptic Pole (SEP; J0443-5340) at 24 and 70um with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and BLAST. We discuss our data reduction and source extraction procedures. The median 1{sigma} depths of the maps are 47uJy/beam at 24um and 4.3mJy/beam at 70um. At 24um, we identify 93098 point sources with signal-to-noise ratio (S/N)>=5 and an additional 63 resolved galaxies; at 70um we identify 891 point sources with S/N>=6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24um (70um) catalog. The 24 and 70um point-source catalogs are 80% complete at 230uJy and 11mJy, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/671/470
- Title:
- MIPS survey of YSOs in Vela Molecular Ridge-D
- Short Name:
- J/ApJ/671/470
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new, unbiased Spitzer MIPS imaging survey (~1.8deg^2^) of the young stellar content of the Vela Molecular Ridge-D (VMR-D) is presented. The survey is complete down to 5 and 250mJy at 24 and 70{mu}m, respectively. A total of 849 sources are detected at 24{mu}m, and 52 of them also have a 70{mu}m counterpart. The VMR-D region is one that we have already partially mapped in dust and gas millimeter emission, and we discuss the correlation between the Spitzer compact sources and the millimeter contours. About half of the 24{mu}m sources are located inside the region delimited by the ^12^CO(1-0) contours, corresponding to only one-third of the full area mapped with MIPS. Therefore, the 24{mu}m source density increases by about 100% moving from outside to inside the CO contours. For the 70{mu}m sources, the corresponding density increase is a factor of 4. About 400 sources of these have a 2MASS counterpart, and we have used this to construct a Ks versus Ks-[24] diagram and to identify the protostellar population inside the cloud.
