We present X-ray data from the ROSAT all-sky survey for those sources catalogued in the Einstein Extended Medium Sensitivity Survey (EMSS) (Cat. <VII/152>) which have been identified with Galactic stars. This "second epoch" of X-ray data taken 10yr later, is used to study coronal flux variability for the most active examples of late-type stars. About 72% of the EMSS stars have been redetected by ROSAT. While the F-stars appear to have remained constant, we find evidence for a general decrease in X-ray flux for the M and solar-type stars. This is probably due to the fact that an X-ray-selected sample will preferentially detect stars while flaring. In contradiction to this, the RS CVn binaries have been redetected at higher X-ray flux levels for the sample as a whole.
We present an imaging analysis of four low mass stellar clusters (<~5000M_{sun}_) in the outer regions of the LMC in order to shed light on the extended main sequence turn-off (eMSTO) phenomenon observed in high mass clusters. The four clusters have ages between 1-2Gyr and two of them appear to host eMTSOs. The discovery of eMSTOs in such low mass clusters - more than 5 times less massive than the eMSTO clusters previously studied - suggests that mass is not the controlling factor in whether clusters host eMSTOs. Additionally, the narrow extent of the eMSTO in the two older clusters (~2Gyr) is in agreement with predictions of the stellar rotation scenario, as lower mass stars are expected to be magnetically braked, meaning that their colour magnitude diagrams should be better reproduced by canonical simple stellar populations. We also performed a structural analysis on all the clusters and found that a large core radius is not a requisite for a cluster to exhibit an eMSTO.
We determine the morphological types of 2295 galaxies from the ESO Nearby Abell Cluster Survey (ENACS) from CCD images obtained with the Dutch telescope on La Silla. A comparison with morphological types from the literature for 450 of our galaxies shows that the reliability of our classification is quite comparable to that of other classifiers. We recalibrate the ENACS spectral classification with the new morphological types, and find that early- and late-type galaxies can be distinguished from their spectra with 83% reliability. Ellipticals and S0 galaxies can hardly be distinguished on the basis of their spectra, but late spirals can be classified from the spectrum alone with more than 70% reliability.
We present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of our local PSG population have neither early- nor late-type morphologies but occupy a well-defined space within the colour-stellar mass diagram, most notably, the low-mass end of the 'green valley' below the transition mass thought to be the mass division between low-mass star-forming galaxies and high-mass passively evolving bulge-dominated galaxies.
We report on the formation of organic amide polymers via carbonyl-amino group linkages in carbon monoxide and ammonia bearing energetically processed ices of astrophysical relevance. The first group comprises molecules with one carboxyl group and an increasing number of amine moieties starting with formamide (45 u), urea (60 u), and hydrazine carboxamide (75 u). The second group consists of species with two carboxyl (58 u) and up to three amine groups (73 u, 88 u, and 103 u). The formation and polymerization of these linkages from simple inorganic molecules via formamide und urea toward amide polymers is discussed in an astrophysical and astrobiological context. Our results show that long chain molecules, which are closely related to polypeptides, easily form by energetically processing simple, inorganic ices at very low temperatures and can be released into the gas phase by sublimation of the ices in star-forming regions. Our experimental results were obtained by employing reflectron time-of-flight mass spectroscopy, coupled with soft, single photon vacuum ultraviolet photoionization; they are complemented by theoretical calculations.
Energies & radiative transition from ArXII to ZnXXIV
Short Name:
J/ApJS/223/3
Date:
21 Oct 2021
Publisher:
CDS
Description:
Combined relativistic configuration interaction and many-body perturbation calculations are performed for the 359 fine-structure levels of the 2s^2^2p^3^, 2s2p^4^, 2p^5^, 2s^2^2p^2^3l, 2s2p^3^3l, 2p^4^3l, and 2s^2^2p^2^4l configurations in N-like ions from Ar XII to Zn XXIV. Complete and consistent data sets of energies, wavelengths, radiative rates, oscillator strengths, and line strengths for all possible electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among the 359 levels are given for each ion. The present work significantly increases the amount of accurate data for ions in the nitrogen-like sequence, and the accuracy of the energy levels is high enough to enable the identification and interpretation of observed spectra involving the n=3, 4 levels, for which experimental values are largely scarce. Meanwhile, the results should be of great help for modeling and diagnosing astrophysical and fusion plasmas.
This catalog contains calculated tables of the energy deposition into dust grains by photons with energies between 10 eV and 1 MeV. The tables give the deposition for 60 different energies and 15 dust grain sizes. Tables for both silicate and graphite grains are presented. Photoelectric absorption, auger electrons, and Compton scattering are used in the calculations, which were done with a Mie code when necessary and a particle approach when appropriate. The file graphite.dat corresponds to Table 5.1 in the source reference. Silicate.dat corresponds to Table 5.2.
The energy distributions for 27 giants and supergiants of the M spectral type are presented in the region of 3200-7600{AA} with the step of 50{AA}. The observations were made in the Fessenkov Astrophysical institute (Alma-Ata) during 1986-1987 with a spectrophotometer of Seya-Namioka mounted on the 50-cm Cassegrain telescope. The primary standard is Vega with the energy distribution by Hayes (1985IAUS..111..225H). The relative r.m.s. of the results are given in the table3.dat.
We report on the pulse-to-pulse energy distributions and phase-resolved modulation properties for catalogued pulsars in the southern High Time Resolution Universe intermediate-latitude survey. We selected the 315 pulsars detected in a single-pulse search of this survey, allowing a large sample unbiased regarding any rotational parameters of neutron stars.
The intrinsic energy distribution for 41 spectral subclasses in the range of wavelengths of 320-760 nm are derived in the following way: (1) The sources of the spectrophotometric data were taken from three catalogues published in FSU (Kharitonov et al. 1988, Glushneva, ed., 1982, Alekseeva et al. 1992), containing energy distributions of about 2000 stars of different spectral types. (2) MK spectral classes were taken from the Bright Star Catalogue (Hoffleit 1982; hereafter BSC). The paper by Gray and Garrison (1987) was took into account to examine the influence of errors in spectral classification. (3) The quality of stars selected for each subclass was estimated by comparison of the observed and synthetic (U-B) and (B-V) color indices calculated for our energy distributions. The results have been published by Knyazeva and Kharitonov (1993, 1994a, 1994b, 1996a, 1996b)