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Browsing by Subject "Methods: numerical"

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Astrophysically Useful Parameters for Certain Band Systems of BeH, BeD and BeT Molecules

Shanmugavel, R; Bagare, S. P; Rajamanickam, N (Astronomical Observatory, Serbia, 2006-12)

The vibronic (vibration-electronic) transition probability parameters such as Franck-Condon (FC) factors and r-centroids of diatomic molecular species could be useful in the identification of molecular bands and in the ...
Automated detection of double nuclei galaxies using GOTHIC and the discovery of a large sample of dual AGN

Bhattacharya, Anwesh; Nehal, C. P; Mousumi Das; Paswan, Abhishek; Saha, Snehanshu; Combes, Françoise (Oxford University Press on behalf of Royal Astronomical Society, 2023-09)

We present a novel algorithm to detect double nuclei galaxies (DNG) called GOTHIC (Graph-bOosTed iterated HIll Climbing) – that detects whether a given image of a galaxy has two or more closely separated nuclei. Our aim ...
Betti Numbers of Gaussian fields

Park, C; Pranav, P; Pravabati, C; Weygaert, R; Jones, B; Vegter, G; Kim, I; Hidding, J; Hellwing, W. A (The Korean Astronomical Society, 2013-06)

We present the relation between the genus in cosmology and the Betti numbers for excursion sets of three- and two-dimensional smooth Gaussian random fields, and numerically investigate the Betti numbers as a function of ...
Center-to-limb Observations and Modeling of the Ca I 4227 Å Line

Supriya, H. D; Smitha, H. N; Nagendra, K. N; Stenflo, J. O; Bianda, M; Ramelli, R; Ravindra, B; Anusha, L. S (IOP Publishing, 2014-09-20)

The observed center-to-limb variation (CLV) of the scattering polarization in different lines of the Second Solar Spectrum can be used to constrain the height variation of various atmospheric parameters, in particular the ...
The effect of dark matter halo shape on bar buckling and boxy/peanut bulges

Ankit Kumar; Mousumi Das; Kataria, Sandeep Kumar (Oxford University Press on behalf of Royal Astronomical Society, 2022-01)

It is well established that bars evolve significantly after they form in galaxy discs, often changing shape both in and out of the disc plane. In some cases they may bend or buckle out of the disc plane resulting in the ...
The effect of electron scattering redistribution on atomic line polarization

Supriya, H. D; Nagendra, K. N; Sampoorna, M; Ravindra, B (Wiley-Blackwell, 2012-09)

The polarization of spectral lines is generated by the scattering of angularly anisotropic incident radiation field on the atoms in the stellar atmosphere. This atomic scattering polarization is modified by frequency ...
An efficient decomposition technique to solve angle-dependent Hanle scattering problems

Supriya, H. D; Sampoorna, M; Nagendra, K. N; Ravindra, B; Anusha, L. S (Elsevier, 2013-04)

Hanle scattering is an important diagnostic tool to study weak solar magnetic fields. Partial frequency redistribution (PRD) is necessary to interpret the linear polarization observed in strong resonance lines. Usually ...
Evaluation of Astrophysically Useful Parameters for Strontium Monohydride and Deuteride

Sri Ramachandran, P; Rajamanickam, N; Bagare, S. P (Astronomical Observatory, Serbia, 2006-06)

The Franck-Condon factors and r-centroids which are very closely related to transition probabilities, have been evaluated by the more reliable numerical integration procedure for the band systems B^{2}sum - X^{2}sum, ...
Excitation of vertical breathing motion in disc galaxies by tidally-induced spirals in fly-by interactions

Kumar, Ankit; Ghosh, Soumavo; Kataria, Sandeep Kumar; Mousumi Das; Debattista, Victor P (Oxford University Press on behalf of Royal Astronomical Society, 2022-10)

It is now clear that the stars in the Solar neighbourhood display large-scale coherent vertical breathing motions. At the same time, Milky Way-like galaxies experience tidal interactions with satellites/companions during ...
Full non-LTE spectral line formation II. Two-distribution radiation transfer with coherent scattering in the atom’s frame

Paletou, F; Sampoorna, M; Peymirat, C (EDP Sciences, 2023-03)

In this article we discuss a method for obtaining a numerical solution to the so-called full nonlocal thermodynamic equilibrium (nonLTE) radiation transfer problem. More specifically, the usual numerical iterative methods ...
Galaxy flybys: evolution of the bulge, disc, and spiral arms

Ankit Kumar; Mousumi Das; Kataria, Sandeep Kumar (Oxford University Press on behalf of the Royal Astronomical Society, 2021-09)

Galaxy flybys are as common as mergers in low-redshift Universe and are important for galaxy evolution as they involve the exchange of significant amounts of mass and energy. In this study, we investigate the effect of ...
Growth of disc-like pseudo-bulges in SDSS DR7 since z = 0.1

Ankit Kumar; Kataria, Sandeep Kumar (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)

Cosmological simulations predict more classical bulges than their observational counterparts in the local Universe. Here, we quantify evolution of the bulges since z = 0.1 using photometric parameters of nearly 39 000 ...
H0 from ten well-measured time delay lenses

Rathna Kumar, S; Stalin, C. S; Prabhu, T. P (EDP Sciences, 2015-08)

In this work, we present a homogeneous curve-shifting analysis using the difference-smoothing technique of the publicly available light curves of 24 gravitationally lensed quasars, for which time delays have been reported ...
J-state interference signatures in the second solar spectrum. Modeling the Cr I triplet at 5204-5208

Smitha, H. N; Nagendra, K. N; Stenflo, J. O; Bianda, M; Sampoorna, M; Ramelli, R; Anusha, L. S (EDP Sciences, 2012-05)

The scattering polarization in the solar spectrum is traditionally modeled with each spectral line treated separately, but this is generally inadequate for multiplets where J-state interference plays a significant role. ...
Magnetohydrodynamic simulation of the X9.3 flare on 2017 September 6: evolving magnetic topology

Jiang, C; Zou, P; Feng, X; Hu, Qiang; Liu, Rui; Vemareddy, P; Duan, Aiying; Zuo, P; Wang, Yi; Wei, Fengsi (IOP Publishing, 2018-12-10)

Three-dimensional magnetic topology is crucial to understanding the explosive release of magnetic energy in the corona during solar flares. Much attention has been given to the pre-flare magnetic topology to identify ...
Magnetohydrodynamic simulation of the X9.3 flare on 2017 September 6: evolving magnetic topology

Jiang, C; Zou, P; Feng, X; Hu, Qiang; Liu, Rui; Vemareddy, P; Duan, Aiying; Zuo, P; Wang, Yi; Wei, Fengsi (IOP Publishing, 2018-12-10)

Three-dimensional magnetic topology is crucial to understanding the explosive release of magnetic energy in the corona during solar flares. Much attention has been given to the pre-flare magnetic topology to identify ...
Modeling the Quantum Interference Signatures of the Ba II D2 4554 Å Line in the Second Solar spectrum

Smitha, H. N; Nagendra, K. N; Stenflo, J. O; Sampoorna, M (IOP Publishing, 2013-05-10)

Quantum interference effects play a vital role in shaping the linear polarization profiles of solar spectral lines. The Ba II D2 line at 4554 Å is a prominent example, where the F-state interference effects due to the odd ...
Multithermal apparent damping of slow waves due to strands with a Gaussian temperature distribution

Van Doorsselaere, T; Krishna Prasad, S; Pant, V; Banerjee, D; Hood, A (EDP Sciences, 2024-03)

Context. Slow waves in solar coronal loops are strongly damped, but the current theory of damping by thermal conduction cannot explain some observational features. Aims. We investigated the propagation of slow waves in a ...
New models of reflection spectra for terrestrial exoplanets: Present and prebiotic Earth orbiting around stars of different spectral types

Singla, Manika; Sengupta, S (Elsevier B.V., 2023-08)

In order to recognize a habitable exoplanet from future observed spectra, we present new model reflected spectra and geometric albedo for modern and prebiotic (∼3.9 Ga) Earth-like exoplanets orbiting within the habitable ...
Polarized Line Transfer with F-state Interference in a Non-magnetic Medium: Partial Frequency Redistribution Effects in the Collisionless Regime

Smitha, H. N; Sowmya, K; Nagendra, K. N; Sampoorna, M; Stenflo, J. O (IOP Publishing, 2012-10-20)

Quantum interference phenomena manifest themselves in several ways in the polarized solar spectrum formed due to coherent scattering processes. One such effect arises due to interference between the fine structure (J) ...

Browsing by Subject "Methods: numerical"

Browsing by Subject "Methods: numerical"

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