- ID:
- ivo://CDS.VizieR/J/ApJ/803/97
- Title:
- Transitions of methyl formate toward Orion KL
- Short Name:
- J/ApJ/803/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We recently reported the first identification of rotational transitions of methyl formate (HCOOCH_3_) in the second torsionally excited state toward Orion Kleinmann-Low (KL), observed with the Nobeyama 45 m telescope. In combination with the identified transitions of methyl formate in the ground state and the first torsional excited state, it was found that there is a difference in rotational temperature and vibrational temperature, where the latter is higher. In this study, high spatial resolution analysis by using Atacama Large Millimeter/Submillimeter Array (ALMA) science verification data was carried out to verify and understand this difference. Toward the Compact Ridge, two different velocity components at 7.3 and 9.1 km/s were confirmed, while a single component at 7.3 km/s was identified toward the Hot Core. The intensity maps in the ground, first, and second torsional excited states have quite similar distributions. Using extensive ALMA data, we determined the rotational and vibrational temperatures for the Compact Ridge and Hot Core by the conventional rotation diagram method. The rotational temperature and vibrational temperatures agree for the Hot Core and for one component of the Compact Ridge. At the 7.3 km/s velocity component for the Compact Ridge, the rotational temperature was found to be higher than the vibrational temperature. This is different from what we obtained from the results by using the single-dish observation. The difference might be explained by the beam dilution effect of the single-dish data and/or the smaller number of observed transitions within the limited range of energy levels (<=30 K) of E_u_ in the previous study.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/102/435
- Title:
- Transitions of SI in visible and infra-red
- Short Name:
- J/A+AS/102/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/601/A2
- Title:
- Triple ^13^C-substituted ethyl cyanide
- Short Name:
- J/A+A/601/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A recently published astronomical detection of all three doubly ^13^C-substituted ethyl cyanides toward Sgr B2(N2) motivated us to investigate triple ^13^C isotopic species that are expected to be also present in the ISM. We aim to present an experimental study of the rotational spectrum of triple ^13^C-substituted ethyl cyanide, ^13^CH_3_ ^13^CH_2_ ^13^CN, in the frequency range 150-990GHz. We want to use the determined spectroscopic parameters for searching for ^13^CH_3_ ^13^CH_2_ ^13^CN in ALMA data. The main objective of this work is to provide accurate frequency predictions to search for this molecule in the Galactic center source Sagittarius B2(N) and to facilitate its detection in space. The laboratory rotational spectrum of ^13^CH_3_ ^13^CH_2_ ^13^CN has been recorded with the Lille's fast DDS solid-state spectrometer between 150GHz and 990GHz. Results. More than 4000 rotational transitions were identified in the laboratory. The quantum numbers reach J=115 and Ka=39. Watson's Hamiltonian in the A and S reductions were used to analyze the spectra. Accurate spectroscopic parameters were determined. The rotational spectra of the ^13^C containing species CH3CH2CN have been assigned, thus allowing the determination of the rotational and centrifugal distortion constants.
734. UMIST database. 1995
- ID:
- ivo://CDS.VizieR/J/A+AS/121/139
- Title:
- UMIST database. 1995
- Short Name:
- J/A+AS/121/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the release of a new version of the UMIST database for astrochemistry. The database contains the rate coefficients of 3864 gas-phase reactions important in interstellar and circumstellar chemistry and involves 395 species and 12 elements. The previous (1990, Millar et al. 1991A&AS...87..585M) version of this database has been widely used by modellers. In addition to the rate coefficients, we also tabulate permanent electric dipole moments of the neutral species and heats of formation. A numerical model of the chemical evolution of a dark cloud is calculated and important differences to that calculated with the previous database noted.
- ID:
- ivo://CDS.VizieR/J/A+A/342/881
- Title:
- Uncertainties in r-abundance distribution
- Short Name:
- J/A+A/342/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 1&2 correspond to the first estimate of the error factors affecting the {beta} decay rates of highly ionized heavy atoms in stellar environments. The uncertainties in the stellar {beta}-decay and EC rates strongly depend on the relevance of the experimentally unknown transitions at a given temperature and density and the reliability of their evaluated probability. To estimate the temperature- and density-dependent errors on the {beta}-decay rates, we have reiterated the Yokoi & Takahashi (1987, At. Data Nucl. Data Tables 36, 375) calculation with unknown transition rates modified by a typical error value of log(ft)=+/-0.5 (Takahashi 1998, private communication). No transition faster than log(ft)=5 is permitted in this error calculation. Newly measured transition probabilities, e.g. the allowed transition in the ^187^Re bound-state {beta}-decay (Bosch et al., 1996PhRvL..77.5190B), have been considered. Minimum and maximum error factors around the published rates of Yokoi & Takahashi (1987) are given in Tables 1 and 2 at temperatures 1<=T_8_<=4 and electronic densities (expressed in terms of 10^26^cm^-3^ of 1<=N_e_<=30. When the density-dependence does not affect the final uncertainty factor by more than 0.10 between the N_e_=1 and 3 cases, only values at N_e_=10 are given in the tables. Note that an increase of transition probability by log(ft)=0.5 gives rise to an increase of the final rate by a maximum value of 3.16. This maximum variation is obtained for many rates. The derived error factors are used in parametric s-process calculations within the canonical multi-event model to estimate their impact on the predicted s-abundance distribution and the resulting uncertainties on the solar r-abundance distribution.
736. Uranium line list
- ID:
- ivo://CDS.VizieR/J/A+A/618/A118
- Title:
- Uranium line list
- Short Name:
- J/A+A/618/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thorium hollow cathode lamps (HCLs) are used as frequency calibrators for many high resolution astronomical spectrographs, some of which aim for Doppler precision at the 1m/s level. We aim to determine the most suitable combination of elements (Th or U, Ar or Ne) for wavelength calibration of astronomical spectrographs, to characterize differences between similar HCLs, and to provide a new U line list. We record high resolution spectra of different HCLs using a Fourier transform spectrograph: (i) U-Ne, U-Ar, Th-Ne, and Th-Ar lamps in the spectral range from 500 to 1000nm and U-Ne and U-Ar from 1000 to 1700nm; (ii) we systematically compare the number of emission lines and the line intensity ratio for a set of 12 U-Ne HCLs; and (iii) we record a master spectrum of U-Ne to create a new U line list. Uranium lamps show more lines suitable for calibration than Th lamps from 500 to 1000nm. The filling gas of the lamps significantly affects their performance because Ar and Ne lines contaminate different spectral regions. We find differences (up to 88%) in the line intensity of U lines in different lamps from the same batch. We find 8239 isolated lines between 500 and 1700nm that we attribute to U, 3379 of which were not contained in earlier line lists. We suggest using a combination of U-Ne and U-Ar lamps to wavelength-calibrate astronomical spectrographs up to 1um. From 1 to 1.7um, U-Ne shows better properties. The differences in line strength between different HCLs underline the importance of characterizing HCLs in the laboratory. The new 3379 U lines can significantly improve the radial velocity precision of astronomical spectrographs.
737. UVILLSS Catalogue
- ID:
- ivo://CDS.VizieR/VI/84
- Title:
- UVILLSS Catalogue
- Short Name:
- VI/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is an extension in the ultraviolet region (129 to 3903 Angstroems) of the ILLSS catalogue (Coluzzi, 1993; catalog <VI/71>) which lists lines in the optical region. The data are from "Ultraviolet Multiplet Table" (Moore 1950, 1952, 1962) and arranged in two files: the catalogue and the references. There are two versions of each file, one presented in the author's original format, and the second organised as a table. The reference files are arranged by element: for each spectrum the first line contains within parenthesis the Ionization Potential; the grade of analysis; the grade denoting the relative number of classified lines included as compared with the total number classified in the ultraviolet; the date of completion of the manuscript; the limit for three spectra H, He I, He II. The limit in cm-1 has been multiplied by the factor 0.00012345 to obtain the tabulated ionisation potential, which is expressed in electron-Volts. The analysis grades range from A to E, grade A indicating that the analysis is essentially complete ,and grade E that the structure has been recognised, but is limited to a single multiplet or transition. List A, List B, etc., denote the relative numbers of classified lines listed here as compared with the total number classified in the ultraviolet, A denoting that all classified lines in the ultraviolet are listed, and D that only a few of the leading ones are tabulated. The letters on the left, A, B, C, etc. preceding the reference, indicate the source used for the wavelength quoted in the Table. Those papers used only for analysis or intensity follow the ones used for wavelength, and are not preceded by the letters denoting the source. The letters "WL", "I", "T", indicating what was taken from each paper for the Table compilation , denote, respectively, wavelength, intensity, and terms, the last referring to the analysis of the spectrum. These informations are taken from Moore (1950).
738. UV spectrum of CrII
- ID:
- ivo://CDS.VizieR/J/ApJS/202/15
- Title:
- UV spectrum of CrII
- Short Name:
- J/ApJS/202/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report new observations of the spectrum of singly ionized chromium (CrII) in the region 1142-3954{AA}. The spectra were recorded with the National Institute of Standards and Technology 10.7m normal-incidence vacuum spectrograph and FT700 vacuum ultraviolet Fourier transform spectrometer. More than 3600 lines are classified as transitions among 283 even and 368 odd levels. The new spectral data are used to re-optimize the energy levels, reducing their uncertainties by a typical factor of 20.
- ID:
- ivo://CDS.VizieR/J/A+AS/128/361
- Title:
- Vacuum ultraviolet emission band systems of N2
- Short Name:
- J/A+AS/128/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observed wavenumbers of the emission lines belonging to 10 vacuum ultraviolet band systems of molecular nitrogen are classified into 283 bands, 220 of them reported for the first time
- ID:
- ivo://CDS.VizieR/J/ApJS/215/20
- Title:
- Vanadium log(gf) and transition probabilities
- Short Name:
- J/ApJS/215/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (VI) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1m Fourier transform spectrometer (FTS) and a high-resolution echelle spectrometer. The branching fractions are combined with recently published radiative lifetimes from laser-induced fluorescence measurements to determine accurate absolute atomic transition probabilities for the 836 lines. The FTS data are also used to extract new hyperfine structure A coefficients for 26 levels of neutral vanadium. These new laboratory data are applied to determine the V abundance in the Sun and metal-poor star HD 84937, yielding log{epsilon}(V)=3.956+/-0.004 ({sigma}=0.037) based on 93 VI lines and log{epsilon}(V)=1.89+/-0.03 ({sigma}=0.07) based on nine VI lines, respectively, using the Holweger-Muller 1D model. These new VI abundance values for the Sun and HD 84937 agree well with our earlier determinations based upon VII.
