- ID:
- ivo://CDS.VizieR/J/A+AS/116/21
- Title:
- Extinction toward CrA and Lup
- Short Name:
- J/A+AS/116/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star counts technique is used towards southern dark globular filaments situated in the cloud complexes of Corona Australis and Lupus. Tables and maps of the distribution of visual extinction are presented for each filament. Lower limit masses for the filaments and condensations have been estimated and the central coordinates of the condensations are also given. R CrA is the most active star forming region among the filaments studied in this work whereas Lupus 1, with almost the same lower limit of mass, has only a few T Tauri stars and just one young embedded object. The distribution of direction of the magnetic field in the condensations of Lupus, suggests that the condensation morphologies does not have any apparent relation with the magnetic field orientation.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/613/A9
- Title:
- Extinction towards Galactic O stars
- Short Name:
- J/A+A/613/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- O stars are excellent tracers of the intervening ISM because of their high luminosity, blue intrinsic SED, and relatively featureless spectra. We are currently conducting the Galactic O-Star Spectroscopic Survey (GOSSS), which is generating a large sample of O stars with accurate spectral types within several kpc of the Sun. We aim to obtain a global picture of the properties of dust extinction in the solar neighborhood based on optical-NIR photometry of O stars with accurate spectral types. We have processed a carefully selected photometric set with the CHORIZOS code to measure the amount [E(4405-5495)] and type [R_5495_] of extinction towards 562 O-type stellar systems. We have tested three different families of extinction laws and analyzed our results with the help of additional archival data.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A79
- Title:
- FEDReD. Extinction map with 2MASS and Gaia DR2
- Short Name:
- J/A+A/641/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to map the 3D distribution of the interstellar extinction of the Milky Way disk up to distances larger than those probed with the Gaia parallaxes alone. We apply the FEDReD algorithm to the 2MASS near-infrared photometry together with the Gaia DR2 astrometry and photometry. This algorithm uses a Bayesian deconvolution approach, based on an empirical HR-diagram representative of the local thin disk, in order to map the extinction as a function of distance for various fields of view. We analysed more than 5.6 million stars to obtain an extinction map of the entire Galactic disk within |b|<0.24{deg}. This map provides information up to 5kpc in the direction of the Galactic centre and at more than 7kpc in the direction of the anticentre. This map reveals the complete shape of structures known locally, such as the Vela complex or the split of the local arm. Furthermore our extinction map shows many large "clean bubbles" especially one in the Sagittarius-Carina complex, and four others which define a structure that we nickname the butterfly
- ID:
- ivo://CDS.VizieR/J/A+A/655/A68
- Title:
- FEDReD III: Unraveling the 3D structure of Vela
- Short Name:
- J/A+A/655/A68
- Date:
- 10 Mar 2022 07:24:47
- Publisher:
- CDS
- Description:
- The Vela complex is a region of the sky that gathers several stellar and interstellar structures in a few hundred square degrees. Gaia data now allows us to obtain a 3D view of the Vela interstellar structures through the dust extinction. We used the FEDReD (Field Extinction-Distance Relation Deconvolver) algorithm on near-infrared 2MASS data, cross-matched with the Gaia DR2 catalogue, to obtain a 3D cube of extinction density. We applied the FellWalker algorithm on this cube to locate clumps and dense structures. We analysed 18 million stars on 450 deg 2 to obtain the extinction density of the Vela complex from 0.5 to 8kpc at l in [250, 280] and b in [-10, 5].This cube reveals the complete morphology of known structures and relations between them. In particular, we show that the Vela Molecular Ridge is more likely composed by three substructures instead of four, as suggested by the 2D densities. These substructures form the shell of a large cavity. This cavity is visually aligned with the Vela supernova remnant but located at a larger distance. We provide a catalogue of location, distance, size and total dust content of ISM clumps that we extracted.
- ID:
- ivo://CDS.VizieR/J/ApJ/757/51
- Title:
- FIRST-2MASS dust-reddened QSO spectra
- Short Name:
- J/ApJ/757/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 120 dust-reddened quasars identified by matching radio sources detected at 1.4GHz in the Faint Images of the Radio Sky at Twenty Centimeters survey (FIRST) with the near-infrared Two Micron All Sky Survey catalog (2MASS) and color-selecting red sources. Optical and/or near-infrared spectroscopy provide broad wavelength sampling of their spectral energy distributions that we use to determine their reddening, characterized by E(B-V). We demonstrate that the reddening in these quasars is best described by Small-Magellanic-Cloud-like dust. This sample spans a wide range in redshift and reddening (0.1<~z<~3, 0.1<~E(B-V)<~1.5), which we use to investigate the possible correlation of luminosity with reddening. At every redshift, dust-reddened quasars are intrinsically the most luminous quasars. We interpret this result in the context of merger-driven quasar/galaxy co-evolution where these reddened quasars are revealing an emergent phase during which the heavily obscured quasar is shedding its cocoon of dust prior to becoming a "normal" blue quasar. When correcting for extinction, we find that, depending on how the parent population is defined, these red quasars make up <~15%-20% of the luminous quasar population. We estimate, based on the fraction of objects in this phase, that its duration is 15%-20% as long as the unobscured, blue quasar phase.
- ID:
- ivo://CDS.VizieR/J/ApJS/185/32
- Title:
- First-year SDSS-II SN results
- Short Name:
- J/ApJS/185/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the Hubble diagram for 103 Type Ia supernovae (SNe) with redshifts 0.04<z<0.42, discovered during the first season (Fall 2005) of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. These data fill in the redshift "desert" between low- and high-redshift SN Ia surveys. Within the framework of the MLCS2K2 light-curve fitting method, we use the SDSS-II SN sample to infer the mean reddening parameter for host galaxies, R_V_=2.18+/-0.14_stat_+/-0.48_syst_, and find that the intrinsic distribution of host-galaxy extinction is well fitted by an exponential function, P(A_V_)=exp(-A_V_/{tau}_V_), with {tau}_V_=0.334+/-0.088mag. We combine the SDSS-II measurements with new distance estimates for published SN data from the ESSENCE survey, the Supernova Legacy Survey (SNLS), the Hubble Space Telescope (HST), and a compilation of Nearby SN Ia measurements. A new feature in our analysis is the use of detailed Monte Carlo simulations of all surveys to account for selection biases, including those from spectroscopic targeting.
- ID:
- ivo://CDS.VizieR/J/ApJ/696/729
- Title:
- Fluxes and abundances of PNe in M33
- Short Name:
- J/ApJ/696/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The planetary nebula (PN) population of M33 is studied via multifiber spectroscopy with Hectospec at the MMT. In this paper, we present the spectra of 102 PNe, whereas plasma diagnostic and chemical abundances were performed on the 93 PNe where the necessary diagnostic lines were measured. About 20% of the PNe are compatible with being Type I; the rest of the sample is the progeny of an old disk stellar population, with main sequence masses M<3M_{sun}_ and ages t>0.3Gyr. Our observations do not seem to imply that the metallicity gradient across the M33 disk has flattened considerably with time. We report also the discovery of a PN with Wolf-Rayet features, PN039, belonging the class of late [WC] stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/71
- Title:
- Fluxes & physical param. of blended YSOs
- Short Name:
- J/ApJ/864/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Despite significant evidence suggesting that intermediate- and high-mass stars form in clustered environments, how stars form when the available resources are shared is still not well understood. A related question is whether the initial mass function (IMF) is in fact universal across galactic environments, or whether it is an average of IMFs that differ, for example, in massive versus low-mass molecular clouds. One of the long-standing problems in resolving these questions and in the study of young clusters is observational: how to accurately combine multiwavelength data sets obtained using telescopes with different spatial resolutions. The resulting confusion hinders our ability to fully characterize clustered star formation. Here we present a new method that uses Bayesian inference to fit the blended spectral energy distributions and images of individual young stellar objects (YSOs) in confused clusters. We apply this method to the infrared photometry of a sample comprising 70 Spitzer-selected, low-mass (M_cl_<100M_{sun}_) young clusters in the galactic plane, and we use the derived physical parameters to investigate how the distribution of YSO masses within each cluster relates to the total mass of the cluster. We find that for low-mass clusters this distribution is indistinguishable from a randomly sampled Kroupa IMF for this range of cluster masses. Therefore, any effects of self-regulated star formation that affect the IMF sampling are likely to play a role only at larger cluster masses. Our results are also compatible with smoothed particle hydrodynamics models that predict a dynamical termination of the accretion in protostars, with massive stars undergoing this stopping at later times in their evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/621/A38
- Title:
- Gaia catalogue of hot subluminous stars
- Short Name:
- J/A+A/621/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on data from the ESA Gaia Data Release 2 (DR2) and several ground-based, multi-band photometry surveys we have compiled an all-sky catalogue of 39800 hot subluminous star candidates selected in Gaia DR2 by means of colour, absolute magnitude, and reduced proper motion cuts. We expect the majority of the candidates to be hot subdwarf stars of spectral type B and O, followed by blue horizontal branch stars of late B-type (HBB), hot post-AGB stars, and central stars of planetary nebulae. The contamination by cooler stars should be about 10%.
- ID:
- ivo://CDS.VizieR/J/AJ/162/110
- Title:
- Gaia EDR3 census of the Taurus-Auriga complex
- Short Name:
- J/AJ/162/110
- Date:
- 14 Mar 2022 06:44:20
- Publisher:
- CDS
- Description:
- The Taurus-Auriga complex is the prototypical low-mass star-forming region, and provides a unique testbed of the star formation process, which left observable imprints on the spatial, kinematic, and temporal structure of its stellar population. Taurus's rich observational history has uncovered peculiarities that suggest a complicated star-forming event, such as members at large distances from the molecular clouds and evidence of an age spread. With Gaia, an in-depth study of the Taurus census is possible, to confirm membership, identify substructure, and reconstruct its star formation history. We have compiled an expansive census of the greater Taurus region, identifying spatial subgroups and confirming that Taurus is substructured across stellar density. There are two populations of subgroups: clustered groups near the clouds and sparse groups spread throughout the region. The sparse groups comprise Taurus's distributed population, which is on average older than the population near the clouds, and hosts subpopulations up to 15Myr old. The ages of the clustered groups increase with distance, suggesting that the current star formation was triggered from behind. Still, the region is kinematically coherent, and its velocity structure reflects an initial turbulent spectrum similar to Larson's Law that has been modified by dynamical relaxation. Overall, Taurus has a complicated star formation history, with at least two epochs of star formation featuring both clustered and distributed modes. Given the correlations between age and spatial distribution, Taurus might be part of a galaxy-scale star-forming event that can only begin to be understood in the Gaia era.
