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Convective driving, the mechanism originally proposed by Brickhill (1991, 1983) for pulsating white dwarf stars, has gained general acceptance as the generic linear instability mechanism in DAV and DBV white dwarfs. This physical mechanism…

In the vast expanse of our galaxy, white dwarfs (WDs) are natural sentinels, capturing the enigmatic dark matter (DM) particles that incessantly traverse their interiors. These celestial bodies provide a unique vantage point for probing…

High Energy Physics - Phenomenology · Physics 2024-06-06 Jia-Shu Niu

In previous work, Gardiner et al. (1999) found evidence for a discrepancy between the Teff obtained from Balmer lines with that from photometry and fundamental values for A-type stars. An investigation into this anomaly is presented using…

Astrophysics · Physics 2009-11-07 B. Smalley , R. B. Gardiner , F. Kupka , M. S. Bessell

The redshifted 21cm signal from Cosmic Dawn promises to open a new window into the early history of our universe and enable the probing of an unprecedented comoving survey volume. In this work, we revisit the imprint of Warm Dark Matter…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-16 Quentin Decant , Androniki Dimitriou , Laura Lopez Honorez , Bryan Zaldivar

Proton-philic spin-dependent inelastic Dark Matter is a Weakly Inelastic Massive Particle scenario that can explain the DAMA yearly modulation effect in compliance with the constraints from other direct detection Dark Matter searches. We…

High Energy Physics - Phenomenology · Physics 2018-01-10 Seong-Hyeong Kang , Stefano Scopel , Jong-Hyun Yoon

Gravitational model of non-minimally coupled Brans Dicke (BD) scalar field $\phi$ with dynamical unit time-like four vector field is used to study flat Robertson Walker (RW) cosmology in the presence of variable cosmological parameter…

General Relativity and Quantum Cosmology · Physics 2015-09-25 Hossein Ghaffarnejad

Time-resolved scanning Kerr effect microscopy has been used to study magnetization dynamics in Permalloy thin films excited by transient magnetic pulses generated by a micrometer-scale transmission line structure. The results are consistent…

Other Condensed Matter · Physics 2007-05-23 Zhigang Liu , Fabian Giesen , Xiaobin Zhu , Richard D. Sydora , Mark R. Freeman

We suggest that white dwarf (WD) pulsars can compete with neutron star (NS) pulsars for producing the excesses of cosmic ray electrons/positrons observed by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. A merger of two WDs leads to…

High Energy Astrophysical Phenomena · Physics 2015-04-23 Kazumi Kashiyama , Kunihito Ioka , Norita Kawanaka

We present the star formation and dust attenuation properties for a sample of 602 galaxies at redshifts $\rm{3<z<7}$, as part of the JADES survey. Our analysis is based on measurements of the $\rm{H}\alpha/\rm{H}\beta$ Balmer Decrement…

White dwarf photospheric parameters are usually obtained by means of spectroscopic or photometric analysis. These results are not always consistent with each other, with the published values often including just the statistical…

Helium white dwarfs (He WDs) are end products of low-mass red giant donors in close binary systems via stable mass transfer or common envelope evolution. At the end of stable mass transfer, there is a well-known relation between the He WD…

Solar and Stellar Astrophysics · Physics 2025-11-26 Jian Mou , Hai-Liang Chen , Dengkai Jiang , Hongwei Ge , Lifu Zhang , Rizhong Zheng , Xuefei Chen , Zhanwen Han

The determination of atmospheric parameters of white dwarf stars (WDs) is crucial for researches on them. Traditional methodology is to fit the model spectra to observed absorption lines and report the parameters with the lowest $\chi ^2$…

Instrumentation and Methods for Astrophysics · Physics 2021-11-29 Yong Yang , Jingkun Zhao , Jiajun Zhang , Xianhao Ye , Gang Zhao

We present 16 new, and confirm 7 previously identified, DA white dwarfs in the Kepler field through ground-based spectroscopy with the Hale 200", Kitt Peak 4-meter, and Bok 2.3-meter telescopes. Using atmospheric models we determine their…

Solar and Stellar Astrophysics · Physics 2016-10-18 T. F. Doyle , S. B. Howell , V. Petit , S. Lepine

Observational evidence has suggested the possibility of a Galactic halo which is dominated by white dwarfs (WDs). While debate continues concerning the interpretation of this evidence, it is clear that an initial mass function (IMF) biased…

Astrophysics · Physics 2009-11-07 Chris B. Brook , Daisuke Kawata , Brad K. Gibson

Redshift space distortion (RSD) observed in galaxy redshift surveys is a powerful tool to test gravity theories on cosmological scales, but the systematic uncertainties must carefully be examined for future surveys with large statistics.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Takashi Ishikawa , Tomonori Totani , Takahiro Nishimichi , Ryuichi Takahashi , Naoki Yoshida , Motonari Tonegawa

A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their…

Astrophysics of Galaxies · Physics 2017-03-29 Stelios Kazantzidis , Lucio Mayer , Simone Callegari , Massimo Dotti , Leonidas A. Moustakas

There has been a growing interest within the astrophysics community in highly magnetized and fast-spinning white dwarfs (WDs), commonly referred to as HMWDs. WDs with these characteristics are quite uncommon and possess magnetic fields…

Solar and Stellar Astrophysics · Physics 2024-12-20 M. F. Sousa , E. Otoniel , J. G. Coelho , J. C. N. de Araujo

This work investigates the impact of different Modified Gravity (MG) models on the large-scale structures (LSS) properties in relation to the cosmic web (CW), using N-body simulations of f(R) and nDGP models. We analyse the impact of the MG…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-28 Suhani Gupta , Simon Pfeifer , Punyakoti Ganeshaiah Veena , Wojciech A. Hellwing

The study of Stark broadening of neutral helium lines, despite significant advances over recent decades, has not led to updated large grids of helium line profiles relevant to the spectroscopic study of helium-rich stars. While the…

Solar and Stellar Astrophysics · Physics 2026-03-05 Patrick Tremblay , Alain Beauchamp , Pierre Bergeron , Antoine Bédard

Partial frequency redistribution (PRD), describing the formation of the line profile, has negligible observational effects for optical depths smaller than ~10^3, at the resolving power of most current instruments. However, when the spectral…

Earth and Planetary Astrophysics · Physics 2015-05-27 Roxana E. Lupu , Paul D. Feldman , Stephan R. McCandliss , Darrell F. Strobel
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