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- ID:
- ivo://CDS.VizieR/J/ApJS/181/572
- Title:
- Collisional ring galaxies atlas
- Short Name:
- J/ApJS/181/572
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog and imaging atlas of classical (collisional) RING galaxies distilled from the Arp-Madore Atlas of Southern Peculiar Galaxies and Associations and supplemented with other known RING galaxies from the published literature. The catalog lists the original host object, compiles available redshifts, and presents newly determined positions for the central (target) galaxy and its nearest companion(s). 127 collisional RING systems are illustrated and their components identified. All of the RINGS have plausible colliders identified; many are radial-velocity confirmed companions. Finally, we make note of the existence of a rare subclass of RING galaxies exemplified by AM 2136-492, double/concentric RING galaxies. These objects are predicted by numerical simulations, but they appear to be quite rare and/or short lived in nature.
- ID:
- ivo://CDS.VizieR/J/AJ/153/165
- Title:
- Collisions of terrestrial worlds
- Short Name:
- J/AJ/153/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an investigation into the occurrence and properties (stellar age and mass trends) of low- mass field stars exhibiting extreme mid-infrared (MIR) excesses (LIR/L*~>~0.01). Stars for the analysis were initially selected from the Motion Verified Red Stars (MoVeRS) catalog of photometric stars with Sloan Digital Sky Survey, 2MASS, and WISE photometry and significant proper motions. We identify 584 stars exhibiting extreme MIR excesses, selected based on an empirical relationship for main-sequence W1-W3 colors. For a small subset of the sample, we show, using spectroscopic tracers of stellar age (H{alpha} and LiI) and luminosity class, that the parent sample is most likely comprised of field dwarfs (>1Gyr). We also develop the Low-mass Kinematics (LoKi) galactic model to estimate the completeness of the extreme MIR excess sample. Using Galactic height as a proxy for stellar age, the completeness-corrected analysis indicates a distinct age dependence for field stars exhibiting extreme MIR excesses. We also find a trend with stellar mass (using r-z color as a proxy). Our findings are consistent with the detected extreme MIR excesses originating from dust created in a short-lived collisional cascade (<100000-years) during a giant impact between two large planetismals or terrestrial planets. These stars with extreme MIR excesses also provide support for planetary collisions being the dominant mechanism in creating the observed Kepler dichotomy (the need for more than a single mode, typically two, to explain the variety of planetary system architectures Kepler has observed), rather than different formation mechanisms.
- ID:
- ivo://CDS.VizieR/VI/148
- Title:
- Collision Strengths for [Co II] Forbidden Lines - SS4
- Short Name:
- VI/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The list presents electron collision strengths for the forbidden transitions between the fifteen lowest levels of the singly-ionized cobalt, Co^+^, as a function of the electron energy, in an intermediate coupling scheme using the Breit-Pauli relativistic terms as implemented in an R-matrix atomic scattering code. An atomic target for the R-matrix scattering defined by 26 atomic terms is used in these calculations. The data are particularly useful for analyzing the thermodynamic conditions of supernova ejecta.
- ID:
- ivo://CDS.VizieR/VI/149
- Title:
- Collision Strengths for [Co III] Forbidden Lines - SS5
- Short Name:
- VI/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The list presents electron collision strengths for the forbidden transitions between the fifteen lowest levels of the doubly-ionized cobalt, Co^2+^, as a function of the electron energy, in an intermediate coupling scheme using the Breit-Pauli relativistic terms as implemented in an R-matrix atomic scattering code. An atomic target for the R-matrix scattering defined by 36 atomic terms is used in these calculations. The data are particularly useful for analyzing the thermodynamic conditions of supernova ejecta.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/24
- Title:
- Collision strengths for transitions in Fe VII
- Short Name:
- J/ApJ/788/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extensive calculations have been performed for electron impact excitation collision strengths and oscillator strengths for the Fe VII extreme ultraviolet lines of astrophysical importance. The collision strengths for fine-structure transitions are calculated in the B-spline Breit-Pauli R-matrix approach. The target wavefunctions have been calculated in the multiconfiguration Hartree-Fock method with term-dependent non-orthogonal orbitals. The close-coupling expansion includes 189 fine-structure levels of Fe VII belonging to terms of the ground 3p^6^ 3d^2^ and excited 3p^5^ 3d^3^, 3p^6^ 3d4l, 3p^6^ 3d5s, and 3p^6^ 3d5p configurations. The effective collision strengths are determined from the electron excitation collision strengths by integration over a Maxwellian distribution of electron velocities. The effective collision strengths are provided for 17766 fine-structure transitions at electron temperatures from 10^4^ to 10^7^ K. Our results normally agree with the previous R-matrix frame-transformation calculations by Witthoeft & Badnell (2008A&A...481..543W). However, there are important differences for some transitions with the previous calculations. The corrections to the previous results are mainly due to more extensive expansions for the Fe VII target states.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/174
- Title:
- Collision strengths in FeIX
- Short Name:
- J/ApJ/812/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Collision strengths and thermally averaged collision strengths for a large number of extreme-ultraviolet lines of FeIX arising by electron impact have been reported. The thermally averaged collision strengths are calculated at electron temperatures in the range 10^4^-10^7^K for the 122043 forbidden and allowed transitions between the 370 fine-structure levels. The atomic parameters for FeIX play an important role in modeling of various astrophysical plasmas, including especially the solar corona. The B-spline Breit-Pauli R-matrix method has been used in the calculation of collision strengths. The target wave functions and transition probabilities have been determined by combining the multiconfiguration Hartree-Fock method with the B-spline box-based multichannel expansions. We have included 370 fine-structure levels of FeIX in the energy region up to 3s^2^3p^5^5s states. The close-coupling expansion includes levels of the 3s^2^3p^6^, 3s^2^3p^5^3d, 4l, 5s, 3s3p^6^3d, 4s, 4p, 3s^2^3p^4^3d^2^, 3s3p^5^3d^2^ configurations and some low-lying levels of the 3s^2^3p^3^3d^3^ configuration in our collision strengths and transition probabilities calculations. There is a good agreement with the previous R-matrix collision strength calculations by Storey et al. (2002, J/A+A/394/753) and Del Zanna et al. (2014, J/A+A/565/A77) for transitions between the lowest 17 levels of the 3s^2^3p^6^, 3s^2^3p^5^3d and 3s3p^6^3d configurations, especially for electron temperatures logT(K)>=5.0. The transitions between the first 17 levels are dominated by Rydberg series of resonances converging to the levels of the 3s^2^3p^4^3d^2^ configuration. The present results and the calculation of Del Zanna et al. show significant differences for many weaker forbidden and intercombination transitions with thermally averaged collision strengths smaller than 0.01.
- ID:
- ivo://CDS.VizieR/J/ApJ/526/544
- Title:
- Collision strengths in S III
- Short Name:
- J/ApJ/526/544
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Electron collisional excitation strengths for transitions between the 3s^2^3p^2^ ^3^P_0,1,2_, ^1^D_2_, and ^1^S_0_ levels and from these levels to the fine-structure levels of the excited 3s3p^3^, 3s^2^3p3d, 3s^2^3p4s, 3s^2^3p4p, and 3s^2^3p4d configurations of S III are calculated in R-matrix approach. We considered 49 fine-structure levels arising from the 27 LS 3s^2^3p^2^ ^3^P, ^1^D, ^1^S, 3s3p^3^ ^5,3^S_o_, ^1,3^D_o_, ^1,3^P_o_, 3s^2^3p3d ^1,3^P_o_, ^1,3^D_o_, ^1,3^F_o_, 3s^2^3p4s ^1,3^P_o_, 3s^2^3p4p ^1,3^S, ^1,3^P, ^1,3^D, 3s^2^3p4d ^1,3^P_o_, and ^1,3^D_o_ states. These target levels are represented by fairly extensive configuration-interaction wave functions. The collision strengths for transitions between fine-structure levels are calculated by transforming the LS-coupled K-matrices to K-matrices in an intermediate coupling scheme. Complicated resonance structures converging to excited state thresholds are explicitly included in collision strengths. The effective collision strengths are obtained from the total collision strengths by integrating over a Maxwellian velocity distribution. These are tabulated over a wide electron temperature range (0.5 - 10) x 10^4^ K.
- ID:
- ivo://CDS.VizieR/J/ApJ/766/109
- Title:
- Color/age/metallicity gradients of E galaxies
- Short Name:
- J/ApJ/766/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to understand the past merging history of elliptical galaxies, we studied the optical-near-infrared (NIR) color gradients of 204 elliptical galaxies. These galaxies are selected from the overlap region of the Sloan Digital Sky Survey (SDSS) Stripe 82 and the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The use of optical and NIR data (g, r, and K) provides large wavelength baselines, and breaks the age-metallicity degeneracy, allowing us to derive age and metallicity gradients. The use of the deep SDSS Stripe 82 images makes it possible for us to examine how the color/age/metallicity gradients are related to merging features. We find that the optical-NIR color and the age/metallicity gradients of elliptical galaxies with tidal features are consistent with those of relaxed ellipticals, suggesting that the two populations underwent a similar merging history on average and that mixing of stars was more or less completed before the tidal features disappeared. Elliptical galaxies with dust features have steeper color gradients than the other two types, even after masking out dust features during the analysis, which can be due to a process involving wet merging. More importantly, we find that the scatter in the color/age/metallicity gradients of the relaxed and merging feature types decreases as their luminosities (or masses) increase at M>10^11.4^M_{sun}_ but stays large at lower luminosities. Mean metallicity gradients appear nearly constant over the explored mass range, but a possible flattening is observed at the massive end.
- ID:
- ivo://CDS.VizieR/J/A+A/397/361
- Title:
- 15-color BATC photometry of Landolt SA95 field
- Short Name:
- J/A+A/397/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present a set of photometric observations in 15 colors of stars in the Landolt SA95 field with the BATC (Beijing-Arizona-Taipei-Connecticut) system. The wavelengths covered by the system range from 300nm to 1000nm. Visual magnitudes of the stars studied in the field are from the 10th to 20th mag. The observational methodology and the data reduction procedures are described. The relationships between the BATC intermediate-band system and the Landolt UBVRI broad band system are obtained. A catalogue of the photometry has been produced which contains the spectral energy distributions (SEDs) of 3613 stars.