- ID:
- ivo://CDS.VizieR/J/other/SciA/1.9
- Title:
- C/2014 Q2 (Lovejoy) spectra
- Short Name:
- J/other/SciA/1.9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of numerous complex organic molecules (COMs; defined as those containing 6 or more atoms) around protostars shows that star formation is accompanied by an increase of molecular complexity. These COMs may be part of the material from which planetesimals and ultimately planets formed. Comets sample some of the oldest and most primitive material in the solar system, including ices, and are thus our best window into the volatile composition of the solar proto-planetary disk. Molecules identified to be present in cometary ices include water, simple hydrocarbons, oxygen, sulfur and nitrogen-bearing species, as well as a few COMs, such as ethylene glycol and glycine. Here, we report the detection of 21 molecules in comet C/2014 Q2 (Lovejoy), including the first identification of ethyl alcohol (ethanol, C2H5OH) and the simplest monosaccharide sugar glycolaldehyde (CH2OHCHO) in a comet. The abundances of ethanol and glycolaldehyde, respectively 5 and 0.8% relative to methanol (0.12 and 0.02% relative to water), are somewhat higher than values measured in solar-type protostars. Overall, the high abundance of COMs in cometary ices supports formation through grain-surface reactions in the solar system protoplanetary disk.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/565/L12
- Title:
- Crab pulsar 50-400GeV light curve
- Short Name:
- J/A+A/565/L12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Crab pulsar is the only astronomical pulsed source detected at very high energy (VHE, E>100GeV) gamma rays. The emission mechanism of VHE pulsation is not yet fully understood, although several theoretical models have been proposed. In order to test new models, we measured the light curve and the spectra of the Crab pulsar with high precision by means of deep observations. We analyzed 135h of selected MAGIC data taken between 2009 and 2013 in stereoscopic mode. In order to discuss the spectral shape in connection with lower energies, 5.5 years of Fermi-LAT data were also analyzed
4043. CRATES sources at 30 GHz
- ID:
- ivo://CDS.VizieR/J/MNRAS/410/2690
- Title:
- CRATES sources at 30 GHz
- Short Name:
- J/MNRAS/410/2690
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Knowledge of the population of radio sources in the range ~2-200GHz is important for understanding their effects on measurements of the cosmic microwave background power spectrum. We report measurements of the 30-GHz flux densities of 605 radio sources from the Combined Radio All-sky Targeted Eight-GHz Survey (CRATES), which have been made with the One Centimetre Receiver Array-prototype (OCRA-p) on the Torun 32-m telescope. The flux densities of sources that were also observed by Wilkinson Microwave Anisotropy Probe (WMAP) and previous OCRA surveys are in broad agreement with those reported here, however a number of sources display intrinsic variability. We find a good correlation between the 30GHz and Fermi gamma-ray flux densities for common sources. We examine the radio spectra of all observed sources and report a number of gigahertz-peaked and inverted spectrum sources. These measurements will be useful for comparison to those from the Low Frequency Instrument of the Planck satellite, which will make some of its most sensitive observations in the region covered here.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/18
- Title:
- Cr, Co, and Ni abundances for metal-poor red giants
- Short Name:
- J/ApJS/237/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the abundances of chromium, cobalt, and nickel in 4113 red giants, including 2277 stars in globular clusters (GCs), 1820 stars in the Milky Way's dwarf satellite galaxies, and 16 field stars. We measured the abundances from mostly archival Keck/DEIMOS medium-resolution spectroscopy with a resolving power of R~6500 and a wavelength range of approximately 6500-9000{AA}. The abundances were determined by fitting spectral regions that contain absorption lines of the elements under consideration. We used estimates of temperature, surface gravity, and metallicity that we previously determined from the same spectra. We estimated systematic error by examining the dispersion of abundances within mono- metallic GCs. The median uncertainties for [Cr/Fe], [Co/Fe], and [Ni/Fe] are 0.20, 0.20, and 0.13, respectively. Finally, we validated our estimations of uncertainty through duplicate measurements, and we evaluated the accuracy and precision of our measurements through comparison to high-resolution spectroscopic measurements of the same stars.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A17
- Title:
- CR Ground Level Enhancements spectra (IGLED)
- Short Name:
- J/A+A/640/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuous measurements of ground-based neutron monitors (NMs) form the main data source to study high-energy/high-intensity solar energetic particle (SEP) events, called ground-level enhancements (GLEs). All available data are collected in the International GLE Database (IGLED, http://gle.oulu.fi), which provides formal NM count-rate increases above the constant pre-increase level due to galactic cosmic rays (GCR). This dataset is used to reconstruct energy spectra of GLE events. However, the assumption of the constant GCR background level throughout GLE events is often invalid. Here we made a major revision of the IGLED dataset and provided a dataset of detrended NM count-rate increases accounting for the variable GCR background. The formal GLE count-rate increases were corrected for the variable GCR background which may vary significantly during GLE events. The corresponding integral omnidirectional fluences of SEPs were reconstructed for all GLEs with the sufficient strength from the detrended data using the "effective rigidity" method. The database of detrended NM count-rate has been reset for all GLE events since 1956. The integral omnidirectional fluences have been estimated for all the GLE evens and parameterized for sufficiently strong ones by the modified Ellison-Ramaty spectral shape. The IGLED has been revisited to account for the variable GCR background. Integral omnidirectional fluences reconstructed for most of GLE events, have benn added to IGLED. This forms a basis for more precise studies of parameters of SEP events and, thus, for Solar and space physics.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A95
- Title:
- C-rich giants synthetic spectrophotometry. IV
- Short Name:
- J/A+A/566/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution and spectral properties of stars on the asymptotic giant branch (AGB) are significantly affected by massloss through dusty stellar winds. Dynamic atmosphere and wind models are an essential tool for studying these evolved stars, both individually and as members of stellar populations, to understand their contribution to the integrated light and chemical evolution of galaxies. This paper is part of a series with the purpose of testing state-of-the-art atmosphere and wind models of C-type AGB stars against observations, and making them available to the community for use in various theoretical and observational studies. We have computed low-resolution spectra and photometry (in the wavelength range 0.35-25um) for a grid of 540 dynamic models with stellar parameters typical of solar-metallicity C-rich AGB stars and with a range of pulsation amplitudes. The models cover the dynamic atmosphere and dusty outflow (if present), assuming spherical symmetry, and taking opacities of gas-phase species and dust grains consistently into account. To characterize the time-dependent dynamic and photometric behaviour of the models in a concise way we defined a number of classes for models with and without winds.Results. Comparisons with observed data in general show a quite satisfactory agreement for example regarding mass-loss rates vs. (J-K) colours or K magnitudes vs. (J-K) colours. Some exceptions from the good overall agreement, however, are found and attributed to the range of input parameters (e.g. relatively high carbon excesses) or intrinsic model assumptions (e.g. small particle limit for grain opacities). While current results indicate that some changes in model assumptions and parameter ranges should be made in the future to bring certain synthetic observables into better agreement with observations, it seems unlikely that these pending improvements will significantly affect the mass-loss rates of the models.
- ID:
- ivo://CDS.VizieR/J/A+A/324/1059
- Title:
- C-rich stars IR and UBVRI photometry
- Short Name:
- J/A+A/324/1059
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A study of circumstellar dust shells (CDS) around carbon stars is presented. This study is based on the analysis of the 1-100{mu}m broad-band spectra of 23 objects which have been monitored in the 1-20{mu}m region over several years at ESO. The sources in the sample range from Irr/SR variables and optical Miras to Extreme Carbon Stars which have only been discovered recently in infrared surveys. A modelling accounting for the photometric variations with phase (with up to 9 spectra per object) has been developed. All the CDSs in the sample can be modelled successfully in spherical geometry with a dust opacity law {prop.to}{lambda}^-1.3^ and a dust formation temperature ~950K. The modelling favors the case of an acceleration of dust, from the site of formation and on a distance of ~10^15^cm, over the case of a uniform expansion. Mass loss rates in the range 0.1-50x10^-6^M_{sun}_/yr are derived. The estimates based on this modelling are consistent with those derived from the CO emission line measurements. In view of the incoming near-infrared surveys (DENIS and 2MASS), an analysis of the location of carbon-rich sources in color diagrams is presented. It is shown that the near-infrared colors are well correlated with the mass loss rate. This property can be used to get an estimate, within a factor 3, of this rate for carbon stars without a priori on the distance.
- ID:
- ivo://CDS.VizieR/J/ApJ/658/345
- Title:
- CRIc photometry of Magellanic Bridge Fields
- Short Name:
- J/ApJ/658/345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on observations of the stellar populations in 12 fields spanning the region between the Magellanic Clouds, made with the Mosaic II camera on the 4m telescope at the Cerro-Tololo Inter-American Observatory. The two main goals of the observations are to characterize the young stellar population (which presumably formed in situ in the Bridge and therefore represents the nearest stellar population formed from tidal debris), and to search for an older stellar component (which would have been stripped from either Cloud as stars, by the same tidal forces that formed the gaseous Bridge). We determine the star formation history of the young inter-Cloud population, which provides a constraint on the timing of the gravitational interaction that formed the Bridge. We do not detect an older stellar population belonging to the Bridge in any of our fields, implying that the material that was stripped from the Clouds to form the Magellanic Bridge was very nearly a pure gas.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A109
- Title:
- CRIRES-POP: high resolution IR spectra library
- Short Name:
- J/A+A/539/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New instrumental capabilities and the wealth of astrophysical information extractable from the near-infrared wavelength region have led to a growing interest in the field of high resolution spectroscopy at 1-5m. We aim to provide a library of observed high-resolution and high signal-to-noise-ratio near-infrared spectra of stars of various types throughout the Hertzsprung-Russell diagram. This is needed for the exploration of spectral features in this wavelength range and for comparison of reference targets with observations and models.
- ID:
- ivo://CDS.VizieR/J/ApJ/667/1267
- Title:
- CrI transition probabilities
- Short Name:
- J/ApJ/667/1267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Branching fraction measurements from Fourier transform spectra in conjunction with published radiative lifetimes are used to determine transition probabilities for 263 lines of neutral chromium.