- ID:
- ivo://CDS.VizieR/J/A+A/558/A131
- Title:
- Model spectra of hot stars at the pre-SN stage
- Short Name:
- J/A+A/558/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the fundamental properties of core-collapse Supernova (SN) progenitors from single stars at solar metallicity. We combine Geneva stellar evolutionary models with initial masses of Mini=20-120M_{sun}_ with atmospheric/wind models using CMFGEN. We provide synthetic photometry and high-resolution spectra of hot stars at the pre-SN stage. For Mini=9-20M_{sun}_, we supplement our analysis using publicly available MARCS model atmospheres of RSGs. We employ observational criteria of spectroscopic classification and find that massive stars, depending on Mini and rotation, end their lives as red supergiants (RSG), yellow hypergiants (YHG), luminous blue variables (LBV), and Wolf-Rayet (WR) stars of the WN and WO spectral types. For rotating models, we obtain the following types of SN progenitors: WO1-3 (Mini<=32M_{sun}_), WN10-11 (25<Mini< 32M_{sun}_), LBV (20<=Mini<25M_{sun}_), G1 Ia+ (18<Mini<20M_{sun}_), and RSGs (9<=Mini<=18M_{sun}_). For non-rotating models, we find spectral types WO1-3 (Mini>40M_{sun}_), WN7-8 (25<Mini<=40M_{sun}_), WN11h/LBV (20<Mini<=25M_{sun}_), and RSGs (9<=Mini<=20M_{sun}_). Our rotating models indicate that SN IIP progenitors are all RSG, SN IIL/b progenitors are 56% LBVs and 44% YHGs, SN Ib progenitors are 96% WN10-11 and 4% WOs, and SN Ic progenitors are all WO stars. We find that not necessarily the most massive and luminous SN progenitors are the brighter ones in a given filter. We show that SN IIP progenitors (RSGs) are bright in the RIJHK_S filters and faint in the UB filters. SN IIL/b progenitors (LBVs and YHGs), and SN Ib progenitors (WNs) are relatively bright in optical/IR filters, while SN Ic progenitors (WOs) are faint in all optical filters. We argue that SN Ib and Ic progenitors from single stars should be undetectable in the available pre-explosion images with the current magnitude limits, in agreement with observational results.
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Search Results
- ID:
- ivo://CDS.VizieR/J/PASJ/63/S379
- Title:
- MOIRCS Deep Survey deep and wide catalogs
- Short Name:
- J/PASJ/63/S379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep J-, H-, and Ks-band imaging data of the MOIRCS Deep Survey (MODS), which was carried out with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) mounted on the Subaru Telescope in the GOODS-North region. The data reach 5{sigma} total limiting magnitudes for point sources of J=23.9, H=22.8, and Ks=22.8 (Vega magnitude) over 103 arcmin^2^ (wide field). In 28 arcmin^2^ of the survey area, which is an ultra-deep field of the MODS (deep field), the data reach 5{sigma} depths of J=24.8, H=23.4, and Ks=23.8. The spatial resolutions of the combined images are FWHM~0.6" and ~0.5" for the wide and deep fields in all bands, respectively. Combining the MODS data with the multi-wavelength public data taken with the HST, Spitzer, and other ground-based telescopes in the GOODS field, we constructed a multi-wavelength photometric catalog of Ks-selected sources.
- ID:
- ivo://CDS.VizieR/J/other/AcApS/18.302
- Title:
- Molecular clouds in 8<l<38, -1<b<+1
- Short Name:
- J/other/AcApS/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A systematic comparison between molecular clouds in different evolutionary stages and processes of star formation is made over the range of 8{deg} to 38{deg} in Galactic longitude and -1{deg} to +1{deg} in Galactic latitude by using the Massachusetts-Stony Brook Survey data of ^12^CO in the Galactic plane (HPFW=47") and the IRAS Infrared Sky Survey image data (1.5' per pixel). This region is divided into thirty subregions. Then, the space distribution of CO(1-0) emission and the corresponding infrared intensity at 60ymis obtained for each subregion, and the contours of infrared color temperatures and optical depths of molecular cloud complexes in the corresponding regions are calculated and derived. Moreover, the catalogs of the IRAS infrared point sources and HII regions are used. Thus, molecular clouds in different evolutionary stages are identified and divided into four groups ranging from young clouds to evolved clouds, and their main characteristics and relations to the processes of star formation are analysed. The Galatic-longitude distributions of ultracompact HII regions and candidate protostars as well as the ratio between HII region-molecular cloud and candidate protostar-molecular cloud associations are analysed statistically. The results indicate that star formation activities are currently still going on in our Galaxy.
- ID:
- ivo://CDS.VizieR/J/PASJ/51/791
- Title:
- Molecular clouds in southern HII regions
- Short Name:
- J/PASJ/51/791
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out extensive ^13^CO(J=1-0) observations toward 23 southern H II regions associated with bright-rimmed clouds. In total, 95 molecular clouds have been identified to be associated with the H II regions. Among the 95, 57 clouds are found to be associated with 204 IRAS point sources which are candidates for young stellar objects. There is a significant increase of star-formation efficiency on the side facing to the H II regions; the luminosity-to-mass ratio, defined as the ratio of the stellar luminosity to the molecular cloud mass, is higher by an order of magnitude on the near side of the H II regions than that on the. far side. This indicates that molecular gas facing to the H II regions is more actively forming massive stars whose luminosity is ~>10^3^L_{sun}_. In addition, the number density of the IRAS point sources increases by a factor of 2 on the near side of the H II regions compared with on the far side. These results strongly suggest that the active formation of massive stars on the near side of the H II regions is due to the effects of the H II regions, such as the compression of molecular material by the ionization/shock fronts. For the whole Galaxy, we estimate that the present star-formation rate under such effects is at least 0.2-0.4M_{sun}_/yr, corresponding to a few 10% by mass.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A109
- Title:
- Molecular gas associated with IRAS 10361-5830
- Short Name:
- J/A+A/570/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the distribution of the molecular gas and dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped HII region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and of investigating the evolutionary state of the young stellar objects identified there.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A96
- Title:
- Molecular gas in Hickson Compact Groups
- Short Name:
- J/A+A/540/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the effect of the extreme environment in Hickson Compact Groups (HCGs) on the molecular gas mass, M_H2_, and the star formation rate (SFR) of galaxies as a function of atomic hydrogen (HI) content and evolutionary phase of the group. We selected a redshift-limited (D<100Mpc) sample of 88 galaxies in 20 HCGs with available atomic hydrogen (HI) VLA maps, covering a wide range of HI deficiencies and evolutionary phases of the groups containing at least one spiral galaxy. We observed the CO(1-0) and CO(2-1) lines with the IRAM 30m telescope for 47 galaxies. Together with literature data, our sample contains CO(1-0) spectra for 86 galaxies. We derived the far-infrared (FIR) luminosity L_FIR_ from IRAS data and used it as a tracer of the star formation rate (SFR). We calculated the HI mass, M_HI_ L_FIR_ and M_H2_ deficiencies, based on the values expected from L_B_ and L_K_ in isolated galaxies from the AMIGA sample. We limited our statistical analysis to spiral galaxies, since the large number of upper limits did not allow drawing strong conclusions about M_H2_ and L_FIR_ in early-type galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/710/150
- Title:
- Molecular lines in EGOs
- Short Name:
- J/ApJ/710/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first systematic survey of molecular lines (including HCO^+^(1-0) and ^12^CO, ^13^CO, C^18^O(1-0) lines at the 3mm band) toward a new sample of 88 massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects or EGOs) identified from the Spitzer GLIMPSE survey in the northern hemisphere with the Purple Mountain Observatory 13.7m radio telescope. By analyzing the asymmetries of the optically thick line HCO^+^ for 69 of 72 EGOs with HCO^+^ detection, we found 29 sources with "blue asymmetric profiles" and 19 sources with "red asymmetric profiles."
- ID:
- ivo://CDS.VizieR/J/A+A/504/853
- Title:
- Molecular lines in 5 massive dense cores
- Short Name:
- J/A+A/504/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two mid-infrared quiet and two brighter massive cores were observed in various transitions (E_up_ up to 289K) of CS, OCS, H_2_S, SO, and SO_2_ and of their ^34^S isotopologues at mm wavelengths with the IRAM 30m and CSO telescopes. The 1D modeling of the dust continuum is used to derive the density and temperature laws, which were then applied in the RATRAN code to modeling the observed line emission and to deriving the relative abundances of the molecules. All lines are detected, except the highest energy SO_2_ transition. Infall (up to 2.9km/s) may be detected towards the core W43MM1. We propose an evolutionary sequence of our sources (W43MM1 - IRAS18264-1152 - IRAS05358+3543 - IRAS18162-2048), based on the SED analysis. The analysis of the variations in abundance ratios from source to source reveals that the SO and SO_2_ relative abundances increase with time, while CS and OCS decrease. Molecular ratios, such as [OCS/H_2_S], [CS/H_2_S], [SO/OCS], [SO_2_/OCS], [CS/SO], and [SO_2_/SO] may be good indicators of evolution, depending on layers probed by the observed molecular transitions. Observations of molecular emission from warmer layers, so that involving higher upper energy levels must be included.
- ID:
- ivo://CDS.VizieR/J/ApJ/780/85
- Title:
- Molecular line study of infrared dark clouds
- Short Name:
- J/ApJ/780/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is currently assumed that infrared dark clouds (IRDCs) represent the earliest evolutionary stages of high-mass stars (>8M_{sun}_). Submillimeter and millimeter-wave studies performed over the past 15yr show that IRDCs possess a broad variety of properties, and hence a wide range of problems and questions that can be tackled. In this paper, we report an investigation of the molecular composition and chemical processes in two groups of IRDCs. Using the Mopra, APEX, and IRAM radio telescopes over the last four years, we have collected molecular line data for CO, H_2_CO, HNCO, CH_3_CCH, CH_3_OH, CH_3_CHO, CH_3_OCHO, and CH_3_OCH_3_. For all of these species we estimated molecular abundances. We then undertook chemical modeling studies, concentrating on the source IRDC028.34+0.06, and compared observed and modeled abundances. This comparison showed that to reproduce observed abundances of complex organic molecules, a zero-dimensional gas-grain model with constant physical conditions is not sufficient. We achieved greater success with the use of a warm-up model, in which warm-up from 10K to 30K occurs following a cold phase.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A22
- Title:
- Monoceros R2 filament hub FIR observations
- Short Name:
- J/A+A/607/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830pc distance, containing several sites of active star formation), as observed at 70um, 160um, 250um, 350um, and 500um by the PACS and SPIRE instruments on the Herschel Space Observatory as part of the HOBYS Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In addition, C^18^O data from the IRAM 30-m Telescope are presented, and used for kinematic information. Sources were extracted from the maps with getsources, and from the fluxes measured, spectral energy distributions were constructed, allowing measurements of source mass and dust temperature. Of 177 Herschel sources robustly detected in the region (a detection with high signal-to-noise and low axis ratio at multiple wavelengths), including protostars and starless cores, 29 are found in a filamentary hub at the centre of the region (a little over 1% of the observed area). These objects are on average smaller, more massive, and more luminous than those in the surrounding regions (which together suggest that they are at a later stage of evolution), a result that cannot be explained entirely by selection effects. These results suggest a picture in which the hub may have begun star formation at a point significantly earlier than the outer regions, possibly forming as a result of feedback from earlier star formation. Furthermore, the hub may be sustaining its star formation by accreting material from the surrounding filaments.
