- ID:
- ivo://CDS.VizieR/J/A+A/573/A129
- Title:
- HeViCS. SPIRE point-source catalogs
- Short Name:
- J/A+A/573/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present three independent catalogs of point-sources extracted from SPIRE images at 250, 350, and 500 micron, acquired with the Herschel Space Observatory as a part of the Herschel Virgo Cluster Survey (HeViCS). The catalogs have been cross-correlated to consistently extract the photometry at SPIRE wavelengths for each object. Sources have been detected using an iterative loop. The source positions are determined by estimating the likelihood to be a real source for each peak on the maps, according to the criterion defined in the sourceExtractorSussextractor task. The flux densities are estimated using the sourceExtractorTimeline, a timeline-based point source fitter that also determines the fitting procedure with the width of the Gaussian that best reproduces the source considered. Afterwards, each source is subtracted from the maps, removing a Gaussian function in every position with the full width half maximum equal to that estimated in sourceExtractorTimeline.
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- ID:
- ivo://CDS.VizieR/J/A+A/597/A114
- Title:
- Hi-GAL cluster candidates physical properties
- Short Name:
- J/A+A/597/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aims are to investigate the clustering of the far-infrared sources from the Herschel infrared Galactic Plane Survey (Hi-GAL) in the Galactic longitude range of -71 to 67{deg}. These clumps, and their spatial distribution, are an imprint of the original conditions within a molecular cloud. This will produce a catalogue of over-densities. The minimum spanning tree (MST) method was used to identify the over-densities in two dimensions. The catalogue was further refined by folding in heliocentric distances, resulting in more reliable over-densities, which are cluster candidates. We found 1633 over-densities with more than ten members. Of these, 496 are defined as cluster candidates because of the reliability of the distances, with a further 1,137 potential cluster candidates. The spatial distributions of the cluster candidates are different in the first and fourth quadrants, with all clusters following the spiral structure of the Milky Way. The cluster candidates are fractal. The clump mass functions of the clustered and isolated are statistically indistinguishable from each other and are consistent with Kroupa's initial mass function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/100
- Title:
- Hi-GAL compact source catalog. -71.0<l<67.0
- Short Name:
- J/MNRAS/471/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschelin five infrared continuum bands between 70 and 500{mu}m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane -71.0{deg}<l<67.0{deg}. The band-merged catalogue contains 100 922 sources with a regular SED, 24584 of which show a 70-{mu}m counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between 'on-arm' and 'interarm' positions.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A149
- Title:
- Hi-GAL. inner Milky Way: +68>=l>=70
- Short Name:
- J/A+A/591/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500{mu}m, encompassing the peak of the spectral energy distribution of cold dust for 8<~T<~50K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68{deg}>~l>~-70{deg} in a |b|<=1{deg} latitude strip. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2{deg}x2{deg} "tile" that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Hi-GAL DR1 images are cirrus noise limited and reach the 1{sigma}-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60"/s scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 120581, 291858, 280143, 161946, and 85811 compact sources in the five bands.
- ID:
- ivo://CDS.VizieR/J/MNRAS/381/1219
- Title:
- High mass-loss AGB stars in the Galactic Bulge
- Short Name:
- J/MNRAS/381/1219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of MSX point sources in the Galactic bulge (|l|<3deg, 1deg<|b|<5deg), observed in the A, C, D and E bands (8-21um), with a total area 48 square degrees and more than 7000 detected sources in the MSX D band (15 micron). We discuss the nature of the MSX sources [mostly asymptotic giant branch (AGB) stars], their luminosities, the interstellar extinction, the mass-loss rate distribution and the total mass-loss rate in the bulge. The mid-infrared data of MSX point sources have been combined with the near-infrared (J, H and Ks) data of Two Micron All Sky Survey. The cross-identification was restricted to Ks-band detected sources with Ks<=11mag. However, for those bright MSX D-band sources ([D]<4.0mag), which do not satisfy this criterion, we have set no Ks-band magnitude cut-off. The bolometric magnitudes and the corresponding luminosities of the MSX sources were derived by fitting blackbody curves. The relation between dM/dt and (Ks-[15])0 was used to derive the mass-loss rate of each MSX source in the bulge fields. Except for very few post-AGB stars, planetary nebulae and OH/IR stars, a large fraction of the detected sources at 15 micron (MSX D band) are AGB stars well above the red giant branch tip. A number of them show an excess in ([A]-[D])0 and (Ks-[D])0 colours, characteristic of mass-loss. These colours, especially (Ks-[D])0, enable estimation of the mass-loss rates (dM/dt) of the sources in the bulge fields which range from 10^-7^ to 10^-4^M_{sun}_/yr. Taking into consideration the completeness of the mass-loss rate bins, we find that the contribution to the integrated mass-loss is probably dominated by mass-loss rates larger than 3x10^-7^M_{sun}_/yr and is about 1.96x10^-4^M_{sun}_/yr/deg^2^ in the `intermediate' and `outer' bulge fields of sources with mass-loss rates, dM/dt>3x10^-7^M_{sun}_/yr. The corresponding integrated mass-loss rate per unit stellar mass is 0.48x10^-11^/yr. Apart from this, the various mid- and near-infrared colour-colour and colour-magnitude diagrams are discussed in the paper to study the nature of the stellar population in the MSX bulge fields.
- ID:
- ivo://CDS.VizieR/J/A+A/417/115
- Title:
- High-mass protostellar candidates
- Short Name:
- J/A+A/417/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present maps of the 850{mu}m and 450{mu}m continuum emission seen towards a sample of 68 high-mass protostellar candidates with luminosities ranging from 10^2.5^L_{sun}_ to ~10^5^L_{sun}_. Most of these candidate high-mass stars are in the earliest stages of evolution, and have not yet developed an ultra-compact HII region. We observe a variety of continuum emission morphologies, from compact symmetric sources through to multiple cores embedded in long filaments of emission. We find on average there is a 65% probability of an IRAS point-source having a companion detection at submillimetre wavelengths. The ratio of integrated flux to peak flux for our detections shows no strong dependence on distance, suggesting the emission we have observed is primarily from scale-free envelopes with power-law density structures. Assuming a near kinematic distance projection, the clumps we detect vary in mass from ~1M_{sun}_ to over 1000M_{sun}_, with a mean clump mass of 330M_{sun}_, column density of 9x10^23cm^-2^ and diameter of ~0.6pc. The high luminosity and low mass of the smallest clumps suggests they are accompanied by a minimal number of stellar companions, while the most massive clumps may be examples of young protogroups and protoclusters. We measure the spectral index of the dust emission ({alpha}) and the spectral index of the dust grain opacity ({beta}) towards each object, finding clumps with morphologies suggestive of strong temperature gradients, and of grain growth in their dense inner regions. We find a mean value for beta of 0.9, significantly smaller than observed towards ultra-compact HII regions.
- ID:
- ivo://CDS.VizieR/J/A+A/498/147
- Title:
- High mass protostellar objects physical parameters
- Short Name:
- J/A+A/498/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a previous work (Paper I, Kumar & Grave, 2007A&A...472..155K) a sample of 380 HMPO targets was studied using the GLIMPSE point source catalog and images. A colour-magnitude analysis of the point sources resulted in the identification of infrared counterparts (IRC) of the (sub)mm cores of HMPO candidates which were considered bona fide targets. We aim to estimate and analyse the physical properties of the infrared counterparts of HMPOs by comparing their spectral energy distributions (SED) with those predicted by radiative transfer accretion models of YSOs.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/112
- Title:
- High-redshift MgII absorption QSOs with FIRE
- Short Name:
- J/ApJ/761/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results from the first systematic survey for Mg II quasar absorption lines at z>2.5. Using infrared spectra of 46 high-redshift quasars, we discovered 111 Mg II systems over a path covering 1.9<z<6.3. Five systems have z>5, with a maximum of z=5.33 --the most distant Mg II system now known. The comoving Mg II line density for weaker systems (W_r_<1.0{AA}) is statistically consistent with no evolution from z=0.4 to 5.5, while that for stronger systems increases three-fold until z~3 before declining again toward higher redshifts. The equivalent width distribution, which fits an exponential, reflects this evolution by flattening as z-->3 before steepening again. The rise and fall of the strong absorbers suggests a connection to the star formation rate density, as though they trace galactic outflows or other byproducts of star formation. The weaker systems' lack of evolution does not fit within this interpretation, but may be reproduced by extrapolating low redshift scaling relations between host galaxy luminosity and absorbing halo radius to earlier epochs. For the weak systems, luminosity-scaled models match the evolution better than similar models based on Mg II occupation of evolving cold dark matter halo masses, which greatly underpredict dN/dz at early times unless the absorption efficiency of small halos is significantly larger at early times. Taken together, these observations suggest that the general structure of Mg II-bearing halos was put into place early in the process of galaxy assembly. Except for a transient appearance of stronger systems near the peak epoch of cosmic star formation, the basic properties of Mg II absorbers have evolved fairly little even as the (presumably) associated galaxy population grew substantially in stellar mass and half-light radius.
- ID:
- ivo://CDS.VizieR/J/ApJ/898/150
- Title:
- High-res. MIKE obs. of metal-poor stars
- Short Name:
- J/ApJ/898/150
- Date:
- 21 Mar 2022 08:50:22
- Publisher:
- CDS
- Description:
- Extensive progress has recently been made in our understanding of heavy-element production via the r-process in the universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational-wave signal detected by LIGO, GW170817. The chemical abundance patterns of metal-poor r-process-enhanced stars provide key evidence for the dominant site(s) of the r-process and whether NSBMs are sufficiently frequent or prolific r-process sources to be responsible for the majority of r-process material in the universe. We present atmospheric stellar parameters (using a nonlocal thermodynamic equilibrium analysis) and abundances from a detailed analysis of 141 metal-poor stars carried out as part of the R-Process Alliance (RPA) effort. We obtained high-resolution "snapshot" spectroscopy of the stars using the MIKE spectrograph on the 6.5m Magellan Clay telescope at Las Campanas Observatory in Chile. We find 10 new highly enhanced r-II (with [Eu/Fe]>+1.0), 62 new moderately enhanced r-I (+0.3<[Eu/Fe]<~+1.0), and 17 new limited-r ([Eu/Fe]<+0.3) stars. Among those, we find 17 new carbon-enhanced metal-poor (CEMP) stars, of which five are CEMP-no. We also identify one new s-process-enhanced ([Ba/Eu]>+0.5) and five new r/s (0.0<[Ba/Eu]<+0.5) stars. In the process, we discover a new ultra-metal-poor (UMP) star at [Fe/H]=-4.02. One of the r-II stars shows a deficit in {alpha} and Fe-peak elements, typical of dwarf galaxy stars. Our search for r-process-enhanced stars by RPA efforts has already roughly doubled the known r-process sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/822/40
- Title:
- High resolution NIR RVs of K2-M4 low-mass stars
- Short Name:
- J/ApJ/822/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (~25-150Myr) moving groups, the young field star {epsilon} Eridani, and 18 nearby (<25pc) low-mass stars and achieved typical single-measurement precisions of 8-15m/s with a long-term stability of 15-50m/s over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ~25-50m/s at ~2.3125{mu}m, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ876bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD160934AB and GJ725AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3{sigma}-5{sigma}. Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of <~5m/s in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.
