- ID:
- ivo://CDS.VizieR/J/A+A/600/A44
- Title:
- Spectral line list of hydantoin
- Short Name:
- J/A+A/600/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hydantoin (Imidazolidine-2, 4-dione, C_3_H_4_N_2_O_2_) is a five-membered heterocyclic compound that is known to arise from prebiotic molecules such as glycolic acid and urea, and to give the simplest amino acid, glycine, by hydrolysis under acidic condition. The gas chromatography combined with the mass spectrometry of carbonaceous chondrites lead to the detection of this molecule as well as several kinds of amino acids. The lack of spectroscopic information, especially on the rotational constants, has prevented us from conducting a search for hydantoin in interstellar space. If a rotational temperature of 100K is assumed as the kinetic temperature of a star-forming region, the spectral intensity is expected to be at its maximum in the millimeter-wave region. Laboratory spectroscopy of hydantoin in the millimeter-wave region is the most important in providing accurate rest frequencies to be used for astronomical research. Pure rotational spectra of hydantoin were observed in the millimeter-wave region using the frequency modulated microwave spectrometer at Toho University. Solid hydantoin was heated to around 150{deg}C to provide appropriate vapor pressure. Quantum chemical calculations suggest that the permanent dipole moment of this molecule lies almost along the b-molecular axis, so that spectral search for b-type R-branch transition has been conducted.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/516/A42
- Title:
- Spectral lines of BK Peg and BW Aqr
- Short Name:
- J/A+A/516/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Double-lined, detached eclipsing binaries are our main source for accurate stellar masses and radii. In this paper we focus on the 1.15-1.70M_{sun}_ interval where convective core overshoot is gradually ramped up in theoretical evolutionary models. We aim to determine absolute dimensions and abundances for the F-type detached eclipsing binary BK Peg, and to perform a detailed comparison with results from recent stellar evolutionary models, including a sample of previously studied systems with accurate parameters.
- ID:
- ivo://CDS.VizieR/J/ApJS/193/17
- Title:
- Spectral-line survey of IRC+10216 at 293-355GHz
- Short Name:
- J/ApJS/193/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a spectral-line survey of the extreme carbon star IRC+10216 carried out between 293.9 and 354.8GHz with the Submillimeter Array. A total of 442 lines were detected, more than 200 for the first time; 149 are unassigned. Maps at an angular resolution of ~3" were obtained for each line. A substantial new population of narrow lines with an expansion velocity of ~4km/s (i.e., ~30% of the terminal velocity) was detected. Most of these are attributed to rotational transitions within vibrationally excited states, emitted from energy levels above the {nu}=0, J=0 ground state with excitation energy of 1000-3000K. Emission from these lines appears to be centered on the star with an angular extent of <1". We use multiple transitions detected in several molecules to derive physical conditions in this inner envelope of IRC+10216.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/3842
- Title:
- Spectral line survey of two LOSs
- Short Name:
- J/MNRAS/446/3842
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of two Mopra 3-mm spectral line surveys of the lines of sight (LOS) towards the Galactic Centre (GC) molecular complexes Sgr B2 (LOS+0.693) and Sgr A (LOS-0.11). The spectra covered the frequency ranges of ~77-93 GHz and ~105-113 GHz. We have detected 38 molecular species and 25 isotopologues. The isotopic ratios derived from column density ratios are consistent with the canonical values, indicating that chemical isotopic fractionation and/or selective photodissociation can be considered negligible (<10 percent) for the GC physical conditions. The derived abundances and rotational temperatures are very similar for both LOSs, indicating very similar chemical and excitation conditions for the molecular gas in the GC. The excitation conditions are also very similar to those found for the nucleus of the starburst galaxy NGC 253. We report for the first time the detection of HCO and HOC^+^ emission in LOS+0.693. Our comparison of the abundance ratios between CS, HCO, HOC^+^ and HCO^+^ found in the two LOSs with those in typical Galactic photodissociation regions (PDRs) and starbursts galaxies does not show any clear trend to distinguish between ultraviolet- and X-ray-induced chemistries. We propose that the CS/HOC^+^ ratio could be used as a tracer of the PDR components in the molecular clouds in the nuclei of galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/232/3
- Title:
- Spectral line surveys of 30 regions
- Short Name:
- J/ApJS/232/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectral line surveys are an indispensable tool for exploring the physical and chemical evolution of astrophysical environments due to the vast amount of data that can be obtained in a relatively short amount of time. We present deep, broadband spectral line surveys of 30 interstellar clouds using two broadband {lambda}=1.3mm receivers at the Caltech Submillimeter Observatory. This information can be used to probe the influence of physical environment on molecular complexity. We observed a wide variety of sources to examine the relative abundances of organic molecules as they relate to the physical properties of the source (i.e., temperature, density, dynamics, etc.). The spectra are highly sensitive, with noise levels <=25mK at a velocity resolution of ~0.35km/s. In the initial analysis presented here, column densities and rotational temperatures have been determined for the molecular species that contribute significantly to the spectral line density in this wavelength regime. We present these results and discuss their implications for complex molecule formation in the interstellar medium.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A37
- Title:
- Spectral log of (i)PTF stripped-envelope SN
- Short Name:
- J/A+A/618/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of 507 spectra of 173 stripped-envelope (SE) supernovae (SNe) discovered by the untargeted Palomar Transient Factory (PTF) and intermediate PTF (iPTF) surveys. Our sample contains 55 TypeIIb SNe (SNeIIb), 45 TypeIb SNe (SNeIb), 56 TypeIc SNe (SNeIc), and 17 TypeIb/c SNe (SNeIb/c). We have compared the SE SN subtypes via measurements of the pseudo-equivalent widths (pEWs) and velocities of the HeI{lambda}{lambda}5876, 7065 and OI{lambda}7774 absorption lines. Consistent with previous work, we find that SNeIc show higher pEWs and velocities in OI{lambda}7774 compared to SNeIIb andIb. The pEWs of the HeI{lambda}{lambda}5876, 7065 lines are similar in SNeIb andIIb after maximum light. The HeI{lambda}{lambda}5876, 7065 velocities at maximum light are higher in SNeIb compared to SNeIIb. We identify an anticorrelation between the HeI{lambda}7065 pEW and OI{lambda}7774 velocity among SNeIIb andIb. This can be interpreted as a continuum in the amount of He present at the time of explosion.It has been suggested that SNeIb andIc have similar amounts of He, and that lower mixing could be responsible for hiding He in SNeIc. However, our data contradict this mixing hypothesis. The observed difference in the expansion rate of the ejecta around maximum light of SNeIc (V_m_=sqrt(2)E_k_/M_ej_~=15000km/s) and SNeIb (V_m_~=9000km/s) would imply an average He mass difference of ~1.4M_{sun}_, if the other explosion parameters are assumed to be unchanged between the SE SN subtypes. We conclude that SNeIc do not hide He but lose He due to envelope stripping.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A78
- Title:
- Spectral models for binary products
- Short Name:
- J/A+A/615/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars stripped of their hydrogen-rich envelope through interaction with a binary companion are generally not considered when accounting for ionizing radiation from stellar populations, despite the expectation that stripped stars emit hard ionizing radiation, form frequently, and live 10-100 times longer than single massive stars. We compute the first grid of evolutionary and spectral models specially made for stars stripped in binaries for a range of progenitor masses (2-20M_{sun}_) and metallicities ranging from solar to values representative for pop II stars. For stripped stars with masses in the range 0.3-7M_{sun}_, we find consistently high effective temperatures (20000-100000K, increasing with mass), small radii (0.2-1R_{sun}_), and high bolometric luminosities, comparable to that of their progenitor before stripping. The spectra show a continuous sequence that naturally bridges subdwarf-type stars at the low-mass end and Wolf-Rayet-like spectra at the high-mass end. For intermediate masses we find hybrid spectral classes showing a mixture of absorption and emission lines. These appear for stars with mass-loss rates of 10^-8^-10^-6^M_{sun}_/yr, which have semi-transparent atmospheres. At low metallicity, substantial hydrogen-rich layers are left at the surface and we predict spectra that resemble O-type stars instead. We obtain spectra undistinguishable from subdwarfs for stripped stars with masses up to 1.7M_{sun}_, which questions whether the widely adopted canonical value of 0.47M_{sun}_ is uniformly valid. Only a handful of stripped stars of intermediate mass have currently been identified observationally. Increasing this sample will provide necessary tests for the physics of interaction, internal mixing, and stellar winds. We use our model spectra to investigate the feasibility to detect stripped stars next to an optically bright companion and recommend systematic searches for their UV excess and possible emission lines, most notably HeII {lambda}4686 in the optical and HeII {lambda}1640 in the UV. Our models are publicly available for further investigations or inclusion in spectral synthesis simulations.
- ID:
- ivo://CDS.VizieR/J/A+A/596/A95
- Title:
- Spectral nuclear properties of NLS1 galaxies
- Short Name:
- J/A+A/596/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is not yet well known whether narrow line Seyfert 1 (NLS1) galaxies follow the M_BH_-{sigma}_*_ relation found for normal galaxies. Emission lines, such as [SII] or [OIII]{lambda}5007, have been used as a surrogate of the stellar velocity dispersion and various results have been obtained. On the other hand, some active galactic nuclei (AGNs) have shown Balmer emission with an additional intermediate component (IC) besides the well-known narrow and broad lines. The properties of this IC have not yet been fully studied. In order to re-examine the location of NLS1 in the M_BH_-{sigma}_*_ relation, we test some emission lines, such as the narrow component (NC) of H{alpha} and the forbidden [NII]{lambda}{lambda}6548,6584 and [SII]{lambda}{lambda}6716,6731 lines, as replacements for {sigma}_*_. On the other hand, we study the properties of the IC of H{alpha} found in 14 galaxies of the sample to find a link between this component, the central engine, and the remaining lines. We also compare the emission among the broad component (BC) of H{alpha} and those emitted at the narrow line region (NLR) to detect differences in the ionizing source in each emitting region. We have obtained and studied medium-resolution spectra (170km/s FWHM at H{alpha}) of 36 NLS1 galaxies in the optical range ~5800-6800{AA}. We performed a Gaussian decomposition of the H{alpha}+[NII]{lambda}{lambda}6548,6584 profile to study the distinct components of H{alpha} and [NII] lines. We also measured the [SII] lines. We obtained black hole (BH) masses in the range log(M_{BH}_/M_{sun}_)=5.4-7.5 for our sample. We found that, in general, most of the galaxies lie below the M_BH_-{sigma}_*_ relation when the NC of H{alpha} and [NII] lines are used as a surrogate of {sigma}_*_. The objects are closer to the relation when [SII] lines are used. Nevertheless, the galaxies are still below this relation and we do not see a clear correlation between the BH masses and FWHM_[SII]_. Besides this, we found that 13 galaxies show an IC, most of which are in the velocity range ~700-1500km/s. This is same range as in AGN types and is well correlated with the FWHM of BC and, therefore, with the BH mass. On the other hand, we found that there is a correlation between the luminosity of the BC of H{alpha} and NC, IC, [NII]{lambda}6584, and [SII] lines.
- ID:
- ivo://CDS.VizieR/J/A+A/479/529
- Title:
- Spectral observations of symbiotic LL Cas
- Short Name:
- J/A+A/479/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- All tables contain the results of the spectral and photometric observations of the symbiotic star LL Cas. Observations were carried out within 1986-2006 with a slit spectrograph attached to the 0.7-m telescope of the Fessenkov Astrophysical Institute (Almaty, Kazakhstan). Some photoelectric observations of LL Cas with broad-band filters were carried out on a photoelectric polarimeter mounted on the 1-m Zeiss telescope (Assy-Turgen, Kazakhstan).
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/679
- Title:
- Spectral parameters for MAXI J1543-564
- Short Name:
- J/MNRAS/422/679
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a spectral-timing analysis of the black hole X-ray binary candidate MAXI J1543-564 during its 2011 outburst. All 99 pointed observations of this outburst obtained with the Rossi X-ray Timing Explorer (RXTE) were included in our study. We computed the fundamental diagrams commonly used to study black hole transients, and fitted power density and energy spectra to study the spectral and timing parameters along the outburst. The determination of timing parameters and hence of exact transitions between different states was hampered by the rather low count rate at which this outburst was observed. We detected two periods of exponential decay, one after the source was brightest, which was interrupted by several flares, and another one during the high soft state. The detection of these decays allowed us to obtain an estimate for the source distance of at least 8.5kpc. This leaves two possible explanations for the observed low count rate; either the source has a distance similar to that of other black hole X-ray binary candidates and it is intrinsically faint, or it has a similar luminosity, but is located more than 12 kpc away from us. Furthermore, in the high/soft state the source spectrum appears to be completely disc dominated.