- ID:
- ivo://CDS.VizieR/J/A+A/606/A126
- Title:
- Orion Source I 3mm SiO maser emission
- Short Name:
- J/A+A/606/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-mass star formation remains poorly understood due to observational difficulties (e.g. high dust extinction and large distances) hindering the resolution of disk-accretion and out ow-launching regions. Orion Source I is the closest known massive young stellar object (YSO) and exceptionally powers vibrationally excited SiO masers at radii within 100AU, providing a unique probe of gas dynamics and energetics. We seek to observe and image these masers with Very Long Baseline Interferometry (VLBI). We present the first images of the ^28^SiO v=1, J=2-1 maser emission around Orion Source I observed at ({lambda}2mm) with the Very Long Baseline Array (VLBA). These images have high spatial (~0.3mas) and spectral (~0.054km/s) resolutions.
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- ID:
- ivo://CDS.VizieR/J/A+A/356/1010
- Title:
- Ortho:para-H2 ratio in C and J shocks
- Short Name:
- J/A+A/356/1010
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 2a-f and 4a-f contain an extensive set of parameters derived from our grid of C-type (tables 2a-f) and J-type (tables 4a-f) planar stationary shock models. Models of C-type shocks were calculated for * initial density, nH = 10^3^, 10^4^, 10^5^, 10^6^ cm-3 * shock speed, Vs = 10, 20, 30, 40 km/s (except for nH=10^6^ cm-3, where Vs = 10, 15, 20, 25, 30 km/s) * initial ortho:para-H2 ratio, o/p=0.01, 1, 2, 3 Models of J-type shocks were calculated for * initial density, nH = 10^3^, 10^4^, 10^5^, 10^6^ cm-3 * shock speed, Vs = 5, 10, 15, 20, 25 km/s * initial ortho:para-H2 ratio, o/p=0.01, 1, 2, 3 Tables 2a and 4a list for each model some selected physical parameters (width, duration, temperature, ortho:para ratios ...), tables 2b and 4b contain H2-line fluxes in 0-0 S (0)...S(11), 1-0 S(0)...S(11), and 2-0 S(1) lines, and total H2 luminosity. Tables 2c-f and 4c-f list column densities in each energy level of H2 (each table corresponds to one initial density nH=10^3^, 10^4^, 10^5^ or 10^6^ cm-3).
- ID:
- ivo://CDS.VizieR/J/A+A/620/A46
- Title:
- O2 signature in thin and thick O2-H2O ices
- Short Name:
- J/A+A/620/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we investigate the detectability of the molecular oxygen in icy dust grain mantles towards astronomical objects. We present a systematic set of experiments with O_2_-H_2_O ice mixtures designed to disentangle how the molecular ratio affects the O_2_ signature in the mid- and near-infrared spectral regions. All the experiments were conducted in a closed-cycle helium cryostat coupled to a Fourier transform infrared spectrometer. The ice mixtures comprise varying thicknesses from 8x10^-3^ to 3um. The absorption spectra of the O_2_-H_2_O mixtures are also compared to the one of pure water. In addition, the possibility to detect the O_2_ in icy bodies and in the interstellar medium is discussed. We are able to see the O_2_ feature at 1551cm^-1^ even for the most diluted mixture of H_2_O:O_2_=9:1, comparable to a ratio of O_2_/H_2_O=10% which has already been detected in situ in the coma of the comet 67P/Churyumov-Gerasimenko. We provide an estimate for the detection of O_2_ with the future mission of the James Webb Space Telescope (JWST).
- ID:
- ivo://CDS.VizieR/J/ApJS/144/47
- Title:
- Outer galaxy molecular cloud catalog
- Short Name:
- J/ApJS/144/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Five College Radio Astronomy Observatory (FCRAO) Outer Galaxy Survey (OGS) of ^12^CO(J=1-0) emission was carried out between 1994May and 1997September, using the FCRAO focal plane array QUARRY (Erickson et al. 1992, IEEE Trans. 40, 1), and initially described by Heyer et al. (1998ApJS..115..241H). The OGS covers the Galactic area 102.5<l<141.5, -3<b<54, and the velocity range -152km/s<vlsr<40km/s, at 45'' spatial resolution sampled every 50.22'', and 0.98km/s velocity resolution (1.39km/s for l<106) sampled every 0.81km/s. The typical sensitivity of the OGS at these resolutions is 0.6K (T*_R_ temperature scale). The catalog was generated in a two-phase object identification procedure. The first phase consists of grouping pixels into contiguous structures above a radiation temperature threshold of 0.8K; the second phase decomposes the first-phase objects by an enhanced version of the CLUMPFIND algorithm, using dynamic thresholding, and again with a threshold of 0.8K used for discrimination. Basic attributes of the clouds (coordinates, bounding boxes, integrated intensities, peak observed temperatures) are tabulated in the catalog. A two-dimensional elliptical Gaussian is fitted to the velocity- integrated map of each cloud; the major and minor axis sizes and major axis position angles thus derived are included in the catalog. To the spatially integrated emission line of each cloud, a Gaussian profile is fitted to measure the global linewidth. Model Gaussian clouds, truncated at 0.8K, are examined to determine the effects of biases on measured quantities, induced by truncation. Coupled with detailed analysis of the catalogued clouds, statistical corrections for the effects of truncation on measured sizes, linewidths, and integrated intensities are derived and applied, along with corrections for the effects of finite resolution on the measured attributes. The catalogued emission accounts for 76.4% of the total emission in the Outer Galaxy Survey. The deficit is shown to arise mainly from low-intensity emission on the periphery of larger objects, rather than from a large number of small and/or low-intensity features.
665. Outflow in M82 halo
- ID:
- ivo://CDS.VizieR/J/A+A/293/703
- Title:
- Outflow in M82 halo
- Short Name:
- J/A+A/293/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/572/A40
- Title:
- Outflow of H_2_ gas from NGC3256
- Short Name:
- J/A+A/572/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nuclei of merging galaxies are often deeply buried in dense layers of gas and dust. In these regions, gas outflows driven by starburst and active galactic nuclear activity are believed to play a crucial role in the evolution of these galaxies. However, to fully understand this process it is essential to resolve the morphology and kinematics of such outflows. Using near-infrared integral-field spectroscopy obtained with SINFONI on the Very Large Telescope, we detect a kpc-scale structure of high-velocity molecular hydrogen (H_2_) gas associated with the deeply buried secondary nucleus of the infrared-luminous merger-galaxy NGC 3256. We show that this structure is most likely the hot component of a molecular outflow, which was recently also detected in the cold molecular gas through CO emission.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/20
- Title:
- Outflows and bubbles in Taurus
- Short Name:
- J/ApJS/219/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified outflows and bubbles in the Taurus molecular cloud based on the ~100deg^2^ Five College Radio Astronomy Observatory ^12^CO(1-0) and ^13^CO(1-0) maps and the Spitzer young stellar object catalogs. In the main 44deg^2^ area of Taurus, we found 55 outflows, of which 31 were previously unknown. We also found 37 bubbles in the entire 100deg^2^ area of Taurus, none of which had been found previously. The total kinetic energy of the identified outflows is estimated to be ~3.9x10^45^erg, which is 1% of the cloud turbulent energy. The total kinetic energy of the detected bubbles is estimated to be ~9.2x10^46^erg, which is 29% of the turbulent energy of Taurus. The energy injection rate from the outflows is ~1.3x10^33^erg/s, which is 0.4-2 times the dissipation rate of the cloud turbulence. The energy injection rate from bubbles is ~6.4x10^33^erg/s, which is 2-10 times the turbulent dissipation rate of the cloud. The gravitational binding energy of the cloud is ~1.5x10^48^erg, that is, 385 and 16 times the energy of outflows and bubbles, respectively. We conclude that neither outflows nor bubbles can provide sufficient energy to balance the overall gravitational binding energy and the turbulent energy of Taurus. However, in the current epoch, stellar feedback is sufficient to maintain the observed turbulence in Taurus.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/1
- Title:
- O VI absorption in FUSE survey
- Short Name:
- J/ApJS/146/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the O VI {lambda}{lambda}1031.926, 1037.617 absorption lines associated with gas in and near the Milky Way, as detected in the spectra of a sample of 100 extragalactic targets and two distant halo stars. We combine data from several FUSE Science Team programs with guest observer data that were public before 2002 May 1. The sight lines cover most of the sky above Galactic latitude |b|>25{deg}, at lower latitude the ultraviolet extinction is usually too large for extragalactic observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/125
- Title:
- O VI in the galactic halo
- Short Name:
- J/ApJS/146/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI {lambda}{lambda}1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo.
- ID:
- ivo://CDS.VizieR/J/ApJ/853/151
- Title:
- Oxygen abundances for giant HII regions in NGC 2403
- Short Name:
- J/ApJ/853/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a spectroscopic investigation of 11 HII regions in the nearby galaxy NGC 2403. The HII regions are observed with a long-slit spectrograph mounted on the 2.16m telescope at XingLong station of National Astronomical Observatories of China. For each of the HII regions, spectra are extracted at different nebular radii along the slit-coverage. Oxygen abundances are empirically estimated from the strong-line indices R23, N2O2, O3N2, and N2 for each spectrophotometric unit, with both observation- and model-based calibrations adopted into the derivation. Radial profiles of these diversely estimated abundances are drawn for each nebula. In the results, the oxygen abundances separately estimated with the prescriptions on the basis of observations and models, albeit from the same spectral index, systematically deviate from each other; at the same time, the spectral indices R23 and N2O2 are distributed with flat profiles, whereas N2 and O3N2 exhibit apparent gradients with the nebular radius. Because our study naturally samples various ionization levels, which inherently decline at larger radii within individual HII regions, the radial distributions indicate not only the robustness of R23 and N2O2 against ionization variations but also the sensitivity of N2 and O3N2 to the ionization parameter. The results in this paper provide observational corroboration of the theoretical prediction about the deviation in the empirical abundance diagnostics. Our future work is planned to investigate metal-poor HII regions with measurable Te, in an attempt to recalibrate the strong-line indices and consequently disclose the cause of the discrepancies between the empirical oxygen abundances.
