- ID:
- ivo://CDS.VizieR/J/ApJ/738/5
- Title:
- Effective collision strengths in NiII
- Short Name:
- J/ApJ/738/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present collision strengths and Maxwellian averaged effective collision strengths for the electron-impact excitation of NiII. Attention is expressly concentrated on the optically allowed fine-structure transitions between the 3d^9^, 3d^8^4s, and 3d^7^4s^2^ even parity levels and the 3d^8^4p and 3d^7^4s 4p odd parity levels. The parallel RMATRXII R-matrix package has been recently extended to allow for the inclusion of relativistic fine-structure effects. This suite of codes has been utilized in conjunction with the parallel PSTGF and PSTGICF programs in order to compute converged total collision strengths for the allowed transitions with which this study is concerned. All 113 LS terms identified with the 3d^9^, 3d^8^4s, 3d^7^4s^2^, 3d^8^4p, and 3d^7^4s 4p basis configurations were included in the target wavefunction representation, giving rise to a sophisticated 295 jj-level, 1930 coupled channel scattering complex. Maxwellian averaged effective collision strengths have been computed at 30 individual electron temperatures ranging from 30 to 1000000K. This range comfortably encompasses all temperatures significant to astrophysical and plasma applications.
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- ID:
- ivo://CDS.VizieR/J/A+A/524/A35
- Title:
- Effective collision strengths of CrII
- Short Name:
- J/A+A/524/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Absorption or emission lines of Cr II are observed in a wide variety of astrophysical spectra and accurate atomic data are urgently needed to interpret these lines. Many of these data are impossible to measure experimentally and a full theoretical treatment is the only means by which these data can be obtained.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/206
- Title:
- Effective collision strengths of FeVIII
- Short Name:
- J/ApJ/743/206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New extensive calculations are reported for electron collision strengths, rate coefficients, and transition probabilities for the astrophysically important lines of FeVIII. The collision strengths have been calculated in the close-coupling approximation using the B-spline Breit-Pauli R-matrix method (BSR) code (Zatsarinny 2006CoPhC.174..273Z). The multiconfiguration Hartree-Fock method with term-dependent non-orthogonal orbitals is employed for an accurate representation of the target wave functions. The close-coupling expansion includes 102 fine-structure levels of FeVIII covering all possible terms of the ground 3p^6^3d and singly excited 3p^5^3d^2^, 3p^6^4l, 3p^5^3d4s, 3s3p^6^3d^2^, and 3p^6^5l configurations. The present calculations are more extensive than the previous ones, leading to a total 5151 transitions between fine-structure levels. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities and these are tabulated for all fine-structure transitions at electron temperatures in the range from 5x10^3^ to 5x10^6^K. There is an overall good agreement with the previous 77-state calculations by Griffin, Pindzola, & Badnell (2000A&AS..142..317G), but significant differences are also noted for some transitions.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A55
- Title:
- Effective collision strengths of Ni II
- Short Name:
- J/A+A/513/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Considerable demand exists for electron excitation data for Ni II, since lines from this abundant ion are observed in a wide variety of laboratory and astrophysical spectra. The accurate theoretical determination of these data can present a significant challenge however, due to complications arising from the presence of an open 3d-shell in the description of the target ion.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/2
- Title:
- Effective collision strengths of Si VII
- Short Name:
- J/ApJ/787/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The effective collision strengths for electron-impact excitation of fine-structure transitions in Si VII are calculated as a function of electron temperature in the range 5000-2000000 K. The B-spline Breit-Pauli R-matrix method has been used to calculate collision strengths by electron impact. The target wave functions have been obtained using the multi-configuration Hartree-Fock method with term-dependent non-orthogonal orbitals. The 92 fine-structure levels belonging to the 46 LS states of 2s^2^2p^4^, 2s2p^5^, 2p^6^, 2s^2^2p^3^3s, 2s^2^2p^3^3p, 2s^2^2p^3^3d, and 2s2p^4^3s configurations are included in our calculations of oscillator strengths and collision strengths. There are 4186 possible fine-structure allowed and forbidden transitions among the 92 levels. The present excitation energies, oscillator strengths, and collision strengths have been compared with previous theoretical results and available experimental data. Generally, a good agreement is found with the 6 LS-state close-coupling approximation results of Butler & Zeippen (1994, J/A+AS/108/1) and the 44 LS-state distorted wave calculation of Bhatia & Landi (2003ApJ...585..587B).
- ID:
- ivo://CDS.VizieR/J/A+A/557/A66
- Title:
- Effective SEDs of IR galaxies at various z
- Short Name:
- J/A+A/557/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have revealed a strong correlation between the star formation rate (SFR) and stellarmass of the majority of star-forming galaxies, the so-called star-forming main sequence. An empirical modeling approach (the 2-SFM framework) that distinguishes between the main sequence and rarer starburst galaxies is capable of reproducing most statistical properties of infrared galaxies, such as number counts, luminosity functions, and redshift distributions. In this paper, we extend this approach by establishing a connection between stellar mass and halo mass with the technique of abundance matching. Based on a few simple assumptions and a physically motivated formalism, our model successfully predicts the (cross-)power spectra of the cosmic infrared background (CIB), the crosscorrelation between CIB and cosmic microwave background (CMB) lensing, and the correlation functions of bright, resolved infrared galaxies measured by Herschel, Planck, ACT, and SPT.We use this model to infer the redshift distribution of CIB-anisotropies and of the CIBxCMB lensing signal, as well as the level of correlation between CIB-anisotropies at different wavelengths. Material (effective spectral energy distributions, differential emissivities of halos, relations between Mh and SFR) associated to this model is available at http://irfu.cea.fr/Sap/Phocea/Page/index.php?id=537
- ID:
- ivo://CDS.VizieR/J/A+A/411/559
- Title:
- Effective temperature for 181 F-K dwarfs
- Short Name:
- J/A+A/411/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Line depth ratios measured on high resolution (R=42000), high S/N echelle spectra are used for the determination of precise effective temperatures of 181 F, G, K main Sequence stars with about solar metallicity (-0.5<[Fe/H]<+0.5). A set of 105 relations is obtained which rely Teff on ratios of the strengths of lines with high and low excitation potentials, calibrated against previously published precise (1%) temperature estimates. The application range of the calibrations is 4000-6150K (F8V-K7V). The internal error of a single calibration is less than 100K, while the combination of all calibrations for a spectrum of S/N=100 reduces uncertainty to only 5-10K, and for S/N=200 or higher to better than 5K. The zero point of the temperature scale is directly defined from reflection spectra of the Sun with an uncertainty about 1K. The application of this method to investigation of the planet host stars properties is discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/444/941
- Title:
- Effective temperature of B stars
- Short Name:
- J/A+A/444/941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We establish an empirical effective temperature calibration of main sequence, luminosity class V to III B-type stars for the Delta a photometric system which was originally developed to detect magnetic chemically peculiar objects of the upper main sequence (early B-type to early F-type) at 5200A. However, this system provides the index g1-y which shows an excellent correlation with B-V as well as b-y and can be used as an indicator of the effective temperature. This is supplemented by a very accurate color-magnitude diagram, y or V versus g1-y, which can be used, for example, to determine the reddening, distance and age of an open cluster. This makes the Delta a photometric system an excellent tool to investigate the HR diagram in more detail. Using the reddening-free parameters and already established calibrations within the Stromgren uvbybeta, Geneva 7-color and Johnson UBV systems, a polynomial fit of third degree for the averaged effective temperatures to the individual (g1-y)0 values was derived. For this purpose, data from the literature as well as new observations were taken resulting in 225 suitable bright normal B-type objects. The statistical mean of the error for this sample is 238K which is sufficient to investigate the HRD of distant galactic open clusters as well as extragalactic aggregates in the future.
- ID:
- ivo://CDS.VizieR/J/A+A/443/851
- Title:
- Effective temperature of 30 Dor population
- Short Name:
- J/A+A/443/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star-formation history and IMF of the field population of the 30 Doradus super-association is determined using Wide Field Imager photometry. The cluster NGC 2070 and the OB association LH104 are also studied and used for comparison. The star-formation history of the 30~Doradus super-association appears to be characterized by a large increase in star-formation activity 10Myr to 20Myr ago. This seems to be the case across the whole eastern half of the LMC as demonstrated by the ages of stellar populations as far away as 30 Doradus and Shapley's Constellation III. Star-formation appears to be occurring at a constant rate in the field and in loose associations, and in bursts in the clusters. The field IMF is found to have almost the exact Salpeter slope in the range 7M_{sun}_<=M<=40M_{sun}_, at odds with previous claims. We find that, for objects with more complex star-formation histories, Be stars and selective incompleteness strongly affect the determination of the IMF for M>40M_{sun}_, naturally explaining the observed deviation of the high mass IMF slope from the Salpeter value.The present work supports the idea of a universal IMF.
- ID:
- ivo://CDS.VizieR/J/A+A/391/1039
- Title:
- Effective temperature of metal-poor A-type stars
- Short Name:
- J/A+A/391/1039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective temperatures (T_eff_) can be determined from (V-J)_0_, (V-H)_0_ and (V-K)_0_ colours that are derived from 2MASS magnitudes. This gives another way to estimate the T_eff_ of faint blue halo stars (V<~15) whose temperatures are now usually deduced from (B_V)_0_. Transformations (adapted from Carpenter, 2001AJ....121.2851C) are used to change colours derived from the 2MASS data to the Johnson system. T_eff_ is then derived from these colours using an updated Kurucz model. Tables are given to derive T_eff_ as a function of (V-J)_0_, (V-H)_0_ and (V-K)_0_ for a variety of metallicities and suitable for blue horizontal branch and main sequence stars. The temperatures obtained in this way are compared with those in the recent literature for various stars with 5<=V<=15 and T_eff_ in the range 6500 to 9500K; systematic differences are ~100K. An exception is the sample of BHB stars observed by Wilhelm et al. (1999, Cat. <J/AJ/117/2329>) whose T_eff_ are significantly cooler than those we derive by an amount that increases with increasing temperature. Description: