- ID:
- ivo://CDS.VizieR/J/ApJS/201/13
- Title:
- Submm polarization of Galactic clouds
- Short Name:
- J/ApJS/201/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hertz and SCUBA polarimeters, working at 350um and 850um, respectively, have measured the polarized emission in scores of Galactic clouds. Of the clouds in each data set, 17 were mapped by both instruments with good polarization signal-to-noise ratios. We present maps of each of these 17 clouds comparing the dual-wavelength polarization amplitudes and position angles at the same spatial locations.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/540/A51
- Title:
- Submm spectrum of deuterated glycolaldehydes
- Short Name:
- J/A+A/540/A51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Glycolaldehyde, a sugar-related interstellar prebiotic molecule, has recently been detected in two star-forming regions, Sgr B2(N) and G31.41+0.31. The detection of this new species increased the list of complex organic molecules detected in the interstellar medium (ISM) and adds another level to the chemical complexity present in space. Besides, this kind of organic molecule is important because it is directly linked to the origin of life. For many years, astronomers have been struggling to understand the origin of this high chemical complexity in the ISM. The study of deuteration may provide crucial hints.
- ID:
- ivo://CDS.VizieR/J/A+A/553/A84
- Title:
- (Sub)mm spectrum of deuterated methyl cyanides
- Short Name:
- J/A+A/553/A84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of deuterated abundant molecules is recognized as important in understanding molecular complexity in star-forming regions. We seek to assign the laboratory millimeter and submillimeter wave rotational spectra of the CHD_2_CN and CH_2_DCN deuterated isotopologues of methyl cyanide over a wide frequency range in order to provide precise spectral predictions for observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/899/145
- Title:
- Sulfur isotopes in SFR with 12m ARO and 30m IRAM
- Short Name:
- J/ApJ/899/145
- Date:
- 14 Mar 2022 07:08:41
- Publisher:
- CDS
- Description:
- We present observations of 12C32S, 12C34S, 13C32S, and 12C33S J=2-1 lines toward a large sample of massive star-forming regions by using the Arizona Radio Observatory 12m telescope and the IRAM 30m. Taking new measurements of the carbon 12C/13C ratio, the 32S/34S isotope ratio was determined from the integrated 13C32S/12C34S line intensity ratios for our sample. Our analysis shows a 32S/34S gradient from the inner Galaxy out to a galactocentric distance of 12kpc. An unweighted least-squares fit to our data yields 32S/34S=(1.56{+/-}0.17)DGC+(6.75{+/-}1.22) with a correlation coefficient of 0.77. Errors represent 1{sigma} standard deviations. Testing this result by (a) excluding the Galactic center region, (b) excluding all sources with C34S opacities >0.25, (c) combining our data and old data from previous study, and (d) using different sets of carbon isotope ratios leads to the conclusion that the observed 32S/34S gradient is not an artifact but persists irrespective of the choice of sample and carbon isotope data. A gradient with rising 32S/34S values as a function of galactocentric radius implies that the solar system ratio should be larger than that of the local interstellar medium. With the new carbon isotope ratios, we indeed obtain a local 32S/34S isotope ratio about 10% below the solar system one, as expected in the case of decreasing 32S/34S ratios with time and increased amounts of stellar processing. However, taking older carbon isotope ratios based on a lesser amount of data, such a decrease is not seen. No systematic variation of 34S/33S ratios along galactocentric distance was found. The average value is 5.9{+/-}1.5, the error denoting the standard deviation of an individual measurement.
- ID:
- ivo://CDS.VizieR/II/135
- Title:
- Suppl. to Diffuse Interstellar Band Measurements
- Short Name:
- II/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This bibliographic search has been undertaken in order to gather all data concerning four diffuse interstellar bands (DIB) published since the Snow, York, and Welty (1977) catalogue, and up to 1987.0. These four DIB are : 4430, 5780, 5797, and 6284 Angstrom. In the present set of data, no statistical reduction to a unique system has been made because most of the lists contain only few data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/725
- Title:
- Survey of diffuse interstellar bands
- Short Name:
- J/MNRAS/423/725
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents an atlas of diffuse interstellar bands together with tables with measurements of their parameters: central wavelengths, full widths at half-maximum and equivalent widths. For this goal the spectra of ten reddened, early-type stars have been selected. The spectra are of high resolution, ~100000, and reasonable signal-to-noise ratio, S/N>300; they cover a wide spectral range 3500-10000{AA} and show a lack of evident Doppler splitting in the interstellar KI line. The measurement technique has allowed a homogeneous set of data to be achieved. As a result, the identity of 336 DIBs from previous surveys has been confirmed and 21 new bands have been found.
- ID:
- ivo://CDS.VizieR/J/ApJ/526/788
- Title:
- Survey of infall motions toward starless cores
- Short Name:
- J/ApJ/526/788
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a survey of 220 starless cores selected primarily by their optical obscuration and observed in CS (2-1), N_2_H^+^ (1-0), and C^18^O (1-0) using the Northeast Radio Observatory Corporation (NEROC) Haystack 37 m telescope. We have detected 163 out of 196 sources observed in CS, 72 out of 142 in N_2_H^+^, and 30 out of 30 in C18O. In total, 69 sources were detected in both CS and N_2_H^+^. The isolated component of the N_2_H^+^ (1-0) spectrum (F_1_F = 0,1-1,2) usually shows a weak symmetric profile that is optically thin. In contrast, a significant fraction of the CS spectra show non-Gaussian shapes, which we interpret as arising from a combination of self-absorption due to lower excitation gas in the core front and kinematics in the core. The distribution of the normalized velocity difference ({delta}V_CS_) between the CS and N_2_H^+^ peaks appears significantly skewed to the blue (V_CS_ < 0), as was found in a similar study of dense cores with embedded young stellar objects (YSOs). The incidence of sources with blue asymmetry tends to increase as the total optical depth or the integrated intensity of the N_2_H^+^ line increases.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/44
- Title:
- Survey of SiO maser emission in oxygen-rich stars
- Short Name:
- J/ApJS/253/44
- Date:
- 01 Mar 2022 00:16:35
- Publisher:
- CDS
- Description:
- Circumstellar environments of oxygen-rich stars are among the strongest SiO maser emitters. Physical processes such as collisions, infrared pumping, and overlaps favor the inversion of level population and produce maser emission at different vibrational states. Despite numerous observational and theoretical efforts, we still do not have a unified picture including all of the physical processes involved in SiO maser emission. The aim of this work is to provide homogeneous data in a large sample of oxygen-rich stars. We present a survey of 67 oxygen-rich stars from 7 to 1mm, in their rotational transitions from J=1-0 to J=5-4, for vibrational numbers v from 0 to 6 in the three main SiO isotopologs. We have used one of the 34 m NASA antennas at Robledo and the IRAM 30m radio telescope. The first tentative detection of a v=6 line is reported, as well as the detection of new maser lines. The highest vibrational levels seem confined to small volumes, presumably close to the stars. The J=1-0, v=2 line flux is greater than the corresponding v=1 in almost half of the sample, which may confirm a predicted dependence on the pulsation cycle. This database is potentially useful in models which should consider most of the physical agents, time dependency, and mass-loss rates. As a by-product, we report detections of 27 thermal rotational lines from other molecules, including isotopologs of SiS, H_2_S, SO, SO_2_, and NaCl.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A52
- Title:
- SVS13-A Class I IRAM-NOEMA images
- Short Name:
- J/A+A/654/A52
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Recent results in astrochemistry have revealed that some molecules, such as interstellar complex organic species and deuterated species, can serve as valuable tools in the investigation of star-forming regions. Sulphuretted species can also be used to follow the chemical evolution of the early stages of a Sun-like star formation process. The goal is to obtain a census of S-bearing species using interferometric images towards SVS13-A, a Class I object associated with a hot corino that is rich in interstellar complex organic molecules. To this end, we used the NGC1333 SVS13-A data at 3mm and 1.4mm obtained with the IRAM-NOEMA interferometer in the framework of the SOLIS (Seeds of Life in Space) Large Program. The line emission of S-bearing species was imaged and analyzed using local thermodynamic equilibrium (LTE) and large velocity gradient (LVG) approaches. We imaged the spatial distribution on <=300au scale of the line emission of ^32^SO, ^34^SO, C^32^S, C^34^S, C^33^S, OCS, H_2_C^32^S, H_2_C^34^S, and NS. The low excitation (9K) ^32^SO line traces: (i) the low-velocity SVS13-A outflow and (ii) the fast (up to 100km/s away from the systemic velocity) collimated jet driven by the nearby SVS13-B Class 0 object. Conversely, the rest of the lines are confined in the inner SVS13-A region, where complex organics were previously imaged.More specifically, the non-LTE LVG analysis of SO, SO_2_, and H_2_CS indicates a hot corino origin (size in the 60-120au range). Temperatures between 50K and 300K, as well as volume densities larger than 10^5^cm^-3^ have been derived. The abundances of the sulphuretted are in the following ranges: 0.3-6x10^-6^ (CS), 7x10^-9^-1x10^-7^ (SO), 1-10x10^-7^ (SO_2_), a few 10^-10^ (H_2_CS and OCS), and 10^-10^-10^-9^ (NS). The N(NS)/N(NS+) ratio is larger than 10, supporting the assessment that the NS+ ion is mainly formed in the extended envelope. The [H_2_CS]/[H_2_CO] ratio, once measured at high-spatial resolutions, increases with time (from Class 0 to Class II objects) by more than one order of magnitude (from <=10^-2^ to a few 10^-1^). This suggests that [S]/[O] changes along the process of Sun-like star formation. Finally, the estimate of the [S]/[H] budget in SVS13-A is 2%-17% of the Solar System value (1.8x10^-5^), which is consistent with what was previously measured towards Class 0 objects (1%-8%). This finding supports the notion that the enrichment of the sulphuretted species with respect to dark clouds remains constant from the Class 0 to the Class I stages of lowmass star formation. The present findings stress the importance of investigating the chemistry of star-forming regions using large observational surveys as well as sampling regions on the scale of the Solar System.
840. Swan system of C2
- ID:
- ivo://CDS.VizieR/J/ApJS/169/472
- Title:
- Swan system of C2
- Short Name:
- J/ApJS/169/472
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The C2 Swan system (d ^3^{Pi}_g_-a ^3^{Pi}_u_) was observed in emission for the {Delta}v=-3 to {Delta}v=+2 sequences in the 14000-24000cm^-1^ spectral range using a Fourier transform spectrometer. We carried out a global simultaneous fit by including a wide range of vibrational states. A total of 34 bands with v'=0-10 and v"=0-9 were rotationally assigned. Numerous discrepancies were found in the assignments and in the measured transition wavenumbers between the new measurements and previous results. Most of the measured transition wavenumbers and their assignments for relatively low-v bands agreed with published data. On the contrary, for high-v bands our line positions and assignments disagreed with the tabulated literature values. In particular, the lines of six bands involving the levels with v'=4, 5, and 6 are almost completely different from the previous work. Major sources of the disagreement are thought to be line congestion and perturbations found in these bands. From the analysis, perturbations for v'=0, 1, 2, 4, 6, 8, 9, and 10 in the d ^3^{Pi}_g_ state were identified. A study of these rotational perturbations suggest that some of them are likely caused by interactions with high-v levels of the b ^3^{Sigma}^-^_g_ state.
