- ID:
- ivo://CDS.VizieR/J/ApJS/209/23
- Title:
- Aminoacetonitrile transition frequencies
- Short Name:
- J/ApJS/209/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Aminoacetonitrile, NH_2-CH_2_-CN, has been considered one of the important precursors of glycine, the simplest amino acid, and was identified in Sgr B2(N) by Belloche et al. (2008, Cat. J/A+A/482/179) based on their reanalysis of previous laboratory measurements. However, these laboratory measurements were limited to the 1mm wavelength region even for the normal species, and recent new radio telescopes like ALMA require rest frequencies in a higher frequency range. Therefore, we have extended the pure rotational spectra of aminoacetonitrile and its amino-hydrogen-deuterated isotopologues (NHDCH_2_CN and ND_2_CH_2_CN) up to 1.2THz and 0.6THz, respectively. Belloche et al. indicated that the normal species may have been misassigned in a previous microwave study by Bogey et al. (1990JMoSp.143..180B). We found that two more b-type spectral transitions were misassigned, and all b-type transition frequencies above K_a_=2 had to be remeasured. For isotopologues, spectra above 40 GHz were observed for the first time and higher order centrifugal distortion constants have been determined. The extension of the measurements helped improve the molecular constants. The errors in the frequency catalog data of normal and deuterated isotopologues are on the order of 100kHz up to 1.2THz and 0.6THz, respectively, which are precise enough for the future astronomical observations.
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Search Results
- ID:
- ivo://CDS.VizieR/VI/34
- Title:
- A Multiplet Table for MnI
- Short Name:
- VI/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The machine-readable version of "A Multiplet Table for MnI" contains data on excitation potentials, J values, multiplet terms, intensities of the transitions, and multiplet numbers. Files ordered by multiplet and by wavelength are included.
- ID:
- ivo://CDS.VizieR/J/A+A/432/1063
- Title:
- Analysis of inner solar corona in Extreme-UV
- Short Name:
- J/A+A/432/1063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the differential emission measure (DEM) of a `quiet Sun' area observed in the extreme ultraviolet at normal incidence by the Coronal Diagnostic Spectrometer (CDS) on the SOHO spacecraft. The data used for this work were taken using the NISAT_S_ observing sequence. This takes the full wavelength ranges from both the NIS channels (308-381{AA} and 513-633{AA}) with the 2 arcsec by 240 arcsec slit, which is the narrowest slit available, yielding the best spectral resolution. In this work we contrast the DEM from subregions of 2*80arcsec^2^ with that obtained from the mean spectrum of the whole raster (20*240arcsec^2^). We find that the DEM maintains essentially the same shape in the subregions, differing by a constant factor between 0.5 and 2 from the mean DEM, except in areas were the electron density is below 2*10^7^cm^-3^ and downflow velocities of 50km/s are found in the transition region. Such areas are likely to contain plasma departing from ionisation equilibrium, violating the basic assumptions underlying the DEM method. The comparison between lines of Li-like and Be-like ions may provide further evidence of departure from ionisation equilibrium. We find also that line intensities tend to be lower where velocities of the order of 30km/s or higher are measured in transition region lines. The DEM analysis is also exploited to improve the line identification performed by Brooks et al. (1999A&A...347..277B) and to investigate possible elemental abundance variations from region to region. We find that the plasma has composition close to photospheric in all the subregions examined.
- ID:
- ivo://CDS.VizieR/J/ApJS/181/473
- Title:
- Analysis of the spectrum of {eta} Car
- Short Name:
- J/ApJS/181/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the visible through near-infrared spectrum of Eta Carinae ({eta} Car) and its ejecta obtained during the "{eta} Car Campaign with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT)." This is a part of larger effort to present a complete {eta} Car spectrum, and extends the previously presented analyses with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) in the UV (1240-3159{AA}) to 10430{AA}. The spectrum in the mid- and near-UV is characterized by the ejecta absorption. At longer wavelengths, stellar wind features from the central source and narrow-emission lines from the Weigelt condensations dominate the spectrum. However, narrow absorption lines from the circumstellar shells are present. This paper provides a description of the spectrum between 3060 and 10430{AA}, including line identifications of the ejecta absorption spectrum, the emission spectrum from the Weigelt condensations and the P Cygni stellar wind features. The high spectral resolving power of VLT/UVES enables equivalent width measurements of atomic and molecular absorption lines for elements with no transitions at the shorter wavelengths. However, the ground-based seeing and contributions of nebular-scattered radiation prevent direct comparison of measured equivalent widths in the VLT/UVES and HST/STIS spectra. Fortunately, HST/STIS and VLT/UVES have a small overlap in wavelength coverage which allows us to compare and adjust for the difference in scattered radiation entering the instruments' apertures. This paper provides a complete online VLT/UVES spectrum with line identifications and a spectral comparison between HST/STIS and VLT/UVES between 3060 and 3160{AA}.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/19
- Title:
- A^1^{Pi}-X^1^{Sigma}^+^ transitions of CO study
- Short Name:
- J/ApJ/859/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Highly correlated ab initio calculations were performed for an accurate determination of the A^1^{Pi}-X^1^{Sigma}^+^ system of the CO molecule. A highly accurate multi-reference configuration interaction approach was used to investigate the potential energy curves (PECs) and the transition dipole moment curve (TDMC). The resultant PECs and TDMC found by using the aug-cc-pV5Z (aV5Z) basis set and 5330 active spaces are in good agreement with the experimental data. Moreover, the Einstein A coefficients, lifetimes, ro-vibrational intensities, absorption oscillator strengths, and integrated cross sections are calculated so that the vibrational bands include v"=0-39 -> v'=0-23. For applications in the atmosphere and interstellar clouds, we studied the transition lineshapes to Gaussian and Lorentzian profiles at different temperatures and pressures. The intensities were calculated at high temperature that was used to satisfy some astrophysical applications, such as in planetary atmospheres. The results are potentially useful for important SAO/NASA Astrophysics Data System and databases such as HITRAN, HITEMP, and the National Institute of Standards and Technology. Because the results from many laboratory techniques and our calculations now agree, analyses of interstellar CO based on absorption from A^1^{Pi}-X^1^{Sigma}^+^ are no longer hindered by present spectral parameters.
- ID:
- ivo://CDS.VizieR/J/ApJ/840/81
- Title:
- A^3^{Pi}-X^3^{Sigma}^-^ transitions of OH+
- Short Name:
- J/ApJ/840/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The OH^+^ ion is of critical importance to the chemistry in the interstellar medium and is a prerequisite for the generation of more complex chemical species. Submillimeter and ultraviolet observations rely on high quality laboratory spectra. Recent measurements of the fundamental vibrational band and previously unanalyzed Fourier transform spectra of the near-ultraviolet A^3^{Pi}-X^3^{Sigma}^-^ electronic spectrum, acquired at the National Solar Observatory (NSO) at Kitt Peak in 1989, provide an excellent opportunity to perform a global fit of the available data. These new optical data are approximately four times more precise as compared to the previous values. The fit to the new data provides updated molecular constants, which are necessary to predict the OH^+^ transition frequencies accurately to support future observations. These new constants are the first published using the modern effective Hamiltonian for a linear molecule. These new molecular constants allow for easy simulation of transition frequencies and spectra using the PGOPHER program. The new constants improve simulations of higher J-value infrared transitions, and represent an improvement of an order of magnitude for some constants pertaining to the optical transitions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3660
- Title:
- ARGOS line list {lambda}8395-8830{AA}
- Short Name:
- J/MNRAS/428/3660
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the motivation, field locations and stellar selection for the Abundances and Radial velocity Galactic Origins Survey (ARGOS) spectroscopic survey of 28000 stars in the bulge and inner disc of the Milky Way galaxy across latitudes of b=-5{deg} to -10{deg}. The primary goal of this survey is to constrain the formation processes of the bulge and establish whether it is predominantly a merger or instability remnant. From the spectra (R=11000), we have measured radial velocities and determined stellar parameters, including metallicities and [{alpha}/Fe] ratios. Distances were estimated from the derived stellar parameters and about 14000 stars are red giants within 3.5kpc of the Galactic Centre. In this paper, we present the observations and analysis methods. Subsequent papers (III and IV) will discuss the stellar metallicity distribution and kinematics of the Galactic bulge and inner disc, and the implications for the formation of the bulge.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A86
- Title:
- ArH+ by collision with He
- Short Name:
- J/A+A/631/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of noble gas compounds has gained renewed interest thanks to the recent detection of ArH^+^ in the interstellar medium (ISM). The analysis of physical-chemical conditions in the regions of the ISM where ArH^+^ is observed requires accurate collisional data of ArH^+^ with He, H_2_, electrons, and H. The main goals of this work are to compute the first three-dimensional potential energy surface (PES) to study the interaction of ArH^+^ with He, analyze the influence of the isotopic effects in the rate coefficients, and evaluate the rovibrational relaxation rates. Two ab initio grids of energy were computed at the coupled cluster with single, double, and perturbative triple excitations (CCSD(T)) level of theory using the augmented correlation consistent polarized quadruple, and quintuple zeta basis sets (aug-cc-pVQZ, and aug-cc-pV5Z) and a grid at the complete basis set limit was determined. The analytical representation of the PES was performed using the reproducing kernel Hilbert space (RKHS). The dynamics of the system was studied using the close coupling method. The differences in the rate coefficients for the isotopes ^36^ArH^+^, ^38^ArH^+^, and ^40^ArH^+^ in collision with He are negligible. However, the rotational rates for the collision of ArD+ with He cannot be estimated from those for ArH^+^+He. Comparison with previous rates for the 36ArH++He collision showed discrepancies for |{Delta}j|>2, and in the case of high initial rotational states of 36ArH+ differences were found even for |{Delta}j|=1. The rates for transitions between different vibrational states were also examined. Finally, new sets of rotational rates for ^36^ArH^+^+He and ^36^ArD^+^+He are reported.
- ID:
- ivo://CDS.VizieR/J/A+A/487/383
- Title:
- Ar XVIII radiative and excitation rates
- Short Name:
- J/A+A/487/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report on calculations for energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 25 levels of the n<=5 configurations of H-like Ar XVIII. The general-purpose relativistic atomic structure package (GRASP) and Dirac atomic R-matrix code (DARC) are adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among the 25 levels. Furthermore, collision strengths and effective collision strengths are listed for all 300 transitions among the above 25 levels over a wide energy (temperature) range up to 800Ryd (10^7.4^K).
- ID:
- ivo://CDS.VizieR/J/A+A/649/A60
- Title:
- Assignment & prediction of formaldoxime (CH2NOH)
- Short Name:
- J/A+A/649/A60
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Among the six atoms of N-containing molecules with the formula of CH_3_NO, only formamide (H_2_NCHO), the most stable structural isomer, has been detected in the interstellar medium (ISM). The formaldoxime isomer may be formed, for example, by the reaction of formaldehyde (H_2_CO) or methanimine (H_2_CNH) and hydroxylamine (H_2_NOH), which are all detected in the ISM. The lack of high accuracy millimeter- and submillimeter-wave measurements hinders the astronomical search for formaldoxime. The aim of this work is to provide the direct laboratory measurement of the millimeter- and submillimeter-wave spectrum of trans-formaldoxime. Formaldoxime was synthesized and its rotational spectrum was recorded at room temperature in a glass flow cell using the millimeter- and submillimeter-wave spectrometer in Lille. The SPFIT program in the CALPGM suite was used to fit the spectrum. Rotational lines of trans-formaldoxime from both the ground state and v_12_=1 vibrational excited states have been measured and assigned from 150 to 660GHz. Spectroscopic constants were derived to the tenth order using both Watson's A and S reduction Hamiltonian.
