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1041. Molecular clouds in the Milky Way with CO obs.
ID:
ivo://CDS.VizieR/J/ApJ/828/59
Title:
Molecular clouds in the Milky Way with CO obs.
Short Name:
J/ApJ/828/59
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic plane has been mapped from l=34.75{deg} to 45.25{deg} and b=-5.25{deg} to 5.25{deg} in the CO (J=1-0) emission with the 13.7m telescope of the Purple Mountain Observatory. The unbiased survey covers a large area of 110 square degrees sampled every 30" with a velocity resolution of ~0.2km/s. In this paper, we present the result of an unbiased CO survey of this longitude and latitude range in the velocity range from -60 to -10km/s. Over 500 molecular clouds (MCs) are picked out from the ^12^CO (J=1-0) emission, and 131 of these MCs are associated with ^13^CO emission. The distant MCs, which lie beyond the solar circle and are mostly concentrated in the Galactic plane, trace the large-scale molecular gas structure over 10 degrees of Galactic azimuth. We find that the distribution of the distant MCs can be well fitted by a Gaussian function with a full width at half maximum (FWHM) of 0.7{deg} with the Galactic latitude. We suggest that the CO emission of the segment is from the Outer Arm. The physical mid-plane traced by the Outer Arm seems to be slightly displaced from the IAU-defined plane on a large scale, which could be explained by the warped plane at large Galactocentric distances of >~10kpc and the apparent tilted mid-plane to the projected IAU-defined plane caused by the Sun's z-height above the disk for distances near and within the Solar circle. After removing the effect of the warp and tilted structure, the scale height of the MCs in the Outer Arm is about 0.6{deg} or 160pc at a heliocentric distance of 15kpc. If the inner plane of our Galaxy is flat, we can derive an upper limit of the Sun's offset of ~17.1pc above the physical mid-plane of the Milky Way. We also discuss the correlations between the physical parameters of the distant MCs, which is quite consistent with the result of other studies of this parameter.
1042. Molecular clouds SO and CS obs. I.
ID:
ivo://CDS.VizieR/J/A+AS/144/441
Title:
Molecular clouds SO and CS obs. I.
Short Name:
J/A+AS/144/441
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the article we present a rather extensive mapping survey of 19 molecular clouds in the SO(3_2_-2_1_) and CS(2-1) molecular lines and, at certain positions, also the corresponding 34S isotope lines. Here we present the maps of the survey.
1043. Molecular clouds SO and CS obs. II.
ID:
ivo://CDS.VizieR/J/A+A/358/257
Title:
Molecular clouds SO and CS obs. II.
Short Name:
J/A+A/358/257
Date:
21 Oct 2021
Publisher:
CDS
Description:
We here analyse the observational SO and CS data presented in Nilsson et al. (2000A&AS..144..441N). The SO/CS integrated intensity ratio maps are presented for 19 molecular clouds, together with tables of relevant ratios at strategic positions, where w e have also observed ^34^SO and/or C^34^S.
1044. Molecular gas content of spiral galaxies
ID:
ivo://CDS.VizieR/J/A+A/327/522
Title:
Molecular gas content of spiral galaxies
Short Name:
J/A+A/327/522
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 12CO(J=1-0) line observations of 73 spiral galaxies mostly in the Coma/A1367 supercluster. From these data, combined with data available in the literature, we extract the first complete, optically selected sample (mpg<15.2) of 37 isolated and of 27 cluster galaxies. The 12CO(1-0) line spectra are accessible as postscript figures.
1045. Molecular lines in EGOs
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."
1046. Molecular line study of infrared dark clouds
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.
1047. Molecular line survey of CRL 618
ID:
ivo://CDS.VizieR/J/ApJ/661/250
Title:
Molecular line survey of CRL 618
Short Name:
J/ApJ/661/250
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the complete data set, model, and line identification of a survey of the emission from the C-rich proto-planetary nebula CRL 618 performed with the IRAM 30m telescope in the frequency ranges 80.25-115.75GHz, 131.25-179.25GHz, and 204.25-275.250GHz. A selection of lines from different species has been used in previous works to derive the structure of the source, its physical conditions, and the chemical abundances in the different gas regions. In this work, we have used this information to run a global simulation of the spectrum in order to check the consistency of the model and to ease the task of line identification. The total number of lines that have a correspondence in both data and model is ~3100, although quite often in this object many lines blend into complex features, so that the model, which takes into account line blending, is a key tool at this stage of the analysis. Of all the lines that we have been able to label, ~55% of them belong to the different forms of HC3N, and ~18% to HC5N. The density of remaining unidentified features above the 3sigma limit is only 1 per ~2.1GHz (74 features), which is unprecedented in the analysis of this type of large millimeter-wave line surveys.
1048. Molecular line survey towards UC HII
ID:
ivo://CDS.VizieR/J/A+AS/133/29
Title:
Molecular line survey towards UC HII
Short Name:
J/A+AS/133/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
The tables give identifications for molecular lines detected in the survey of ultracompact HII regions. The survey covers 14 sources: G5.89, G9.62, G10.30, G10.47, G12.21, G13.87, G29.96, G31.41, G34.26, G43.89, G45.12, G45.45, G45.47, and G75.78. For each source, we observed up to ten 1~GHz bands between 200 and 350~GHz, covering lines of more than 30 species including multiple transitions of CO isotopes, CH_3_OH, CH_3_CCH, CH_3_CN and HCOOCH_3, and sulphuretted molecules. The tables give the measured line parameters of observed frequency {nu}(obs), peak temperature T_R_^*^ and linewidth {Delta}{nu}_1/2_ for each line. Each independent detection of a particular line is given. The species, transition, rest frequency and upper level energy (E_u_/k) are given for identified lines.
1049. Molecular maps of NGC1333
ID:
ivo://CDS.VizieR/J/A+A/606/A123
Title:
Molecular maps of NGC1333
Short Name:
J/A+A/606/A123
Date:
21 Oct 2021
Publisher:
CDS
Description:
Are the initial conditions for clustered star formation the same as for non-clustered star formation? To investigate the initial gas properties in young proto-clusters we carried out a comprehensive and high-sensitivity study of the internal structure, density, temperature, and kinematics of the dense gas content of the NGC1333 region in Perseus, one of the nearest and best studied embedded clusters. The analysis of the gas velocities in the Position-Position-Velocity space reveals an intricate underlying gas organization both in space and velocity. We identified a total of 14 velocity-coherent, (tran-)sonic structures within NGC1333, with similar physical and kinematic properties than those quiescent, star-forming (aka fertile) fibers previously identified in low-mass star-forming clouds. These fibers are arranged in a complex spatial network, build-up the observed total column density, and contain the dense cores and protostars in this cloud. Our results demonstrate that the presence of fibers is not restricted to low-mass clouds but can be extended to regions of increasing mass and complexity. We propose that the observational dichotomy between clustered and non-clustered star-forming regions might be naturally explained by the distinct spatial density of fertile fibers in these environments.
1050. Molecules in O- and C-rich envelopes
ID:
ivo://CDS.VizieR/J/A+A/285/247
Title:
Molecules in O- and C-rich envelopes
Short Name:
J/A+A/285/247
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observations of 10 microwave transitions of the molecules SiO, HCN, HNC, SiS, HC_3_N, CS, SO, and ^13^CO are presented in a total sample of 47 evolved stars. The studied sources are mainly O- and C-rich standard AGB stars, as well as O-rich red supergiants, S-type stars, protoplanetary nebulae and detached envelopes. We also take into account observations of these transitions, as well as of ^12^CO J=1-0, from the literature. The observations were carried out during May and September 1991 and June 1992 with the IRAM 30-m radiotelescope at Pico de Veleta (Spain); the resolution is 1MHz for 3mm data (100GHz) and 2 MHz for 2 and 1mm data (150 to 300GHz).