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相关论文: White Dwarf based evaluation of the GALEX absolute…

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Identification of white dwarfs (WD) with main-sequence (MS) companions and characterization of their properties can put important constraints on our understanding of binary stellar evolution and guide the theoretical predictions for a wide…

太阳与恒星天体物理 · 物理学 2023-11-27 Prasanta K. Nayak , Anindya Ganguly , Sourav Chatterjee

We present improved calculations for the Stark broadening of hydrogen lines in dense plasmas typical of white dwarf atmospheres. Our new model is based on the unified theory of Stark broadening from Vidal, Cooper, & Smith. For the first…

太阳与恒星天体物理 · 物理学 2011-02-11 P. -E. Tremblay , P. Bergeron

Metal-poor solar-type stars display a significant reduction in metal-line blanketing at short wavelengths, leading to an excess of near-ultraviolet (NUV) flux compared to their metal-rich counterparts. We utilize GALEX NUV and $\it{Gaia}$…

Context. Understanding the demographics of white dwarf - main sequence (WDMS) binaries is key to uncovering the formation of various stellar exotica and refining the details of binary stellar evolution. Despite several dedicated efforts to…

太阳与恒星天体物理 · 物理学 2026-05-13 Prasanta K. Nayak

The axion, a well-motivated hypothetical particle arising in extensions of the Standard Model, can be produced copiously within the hot, compact cores of white dwarf stars. The shape of the white dwarf luminosity function (WDLF) is a…

太阳与恒星天体物理 · 物理学 2026-03-10 Martín L. Alberino , Marcelo M. Miller Bertolami , María E. Camisassa , Andrea Caputo , Santiago Torres

The evolution of white dwarfs is a simple gravothermal process. This means that their luminosity function, i.e. the number of white dwarfs per unit bolometric magnitude and unit volume as a function of bolometric magnitude, is a…

星系天体物理 · 物理学 2015-06-12 J. Isern , A. Artigas , E. Garcia-Berro

Observations of planetary material polluting the atmospheres of white dwarfs are an important probe of the bulk composition of exoplanetary material. Medium- and high-resolution optical and ultraviolet spectroscopy of seven white dwarfs…

地球与行星天体物理 · 物理学 2023-11-27 L. K. Rogers , A. Bonsor , S. Xu , P. Dufour , B. L. Klein , A. Buchan , S. Hodgkin , F. Hardy , M. Kissler-Patig , C. Melis , A. J. Weinberger , B. Zuckerman

We combine data from the Sloan Digital Sky Survey and the Galaxy Evolution Explorer to simultaneously analyze optical spectra and ultraviolet photometry of 231643 galaxies with the STARLIGHT spectral synthesis code using state-of-the-art…

White dwarf (WD) stars evolve simply and predictably, making them reliable age indicators. However, self-consistent validation of the methods for determining WD total ages has yet to be widely performed. This work uses 1565 wide ( > 100 au)…

太阳与恒星天体物理 · 物理学 2022-08-17 Tyler M. Heintz , J. J. Hermes , Kareem El-Badry , Charlie Walsh , Jennifer L. van Saders , C. E. Fields , Detlev Koester

We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 Mo for our sample, with a dispersion of only 0.09 Mo. White…

Estimating the distances to asymptotic giant branch (AGB) stars using optical measurements of their parallaxes is not straightforward because of the large uncertainties introduced by their dusty envelopes, their large angular sizes, and…

太阳与恒星天体物理 · 物理学 2022-11-09 M. Andriantsaralaza , S. Ramstedt , W. H. T Vlemmings , E. De Beck

In a companion paper (Arnouts et al. 2004) we presented new measurements of the galaxy luminosity function at 1500 Angstroms out to z~1 using GALEX-VVDS observations (1039 galaxies with NUV<24.5 and z>0.2) and at higher z using existing…

We have performed a comprehensive study of the UV emission detected from AGB stars by the Galaxy Evolution Explorer (GALEX). Of the 468 AGB stars in our sample, 316 were observed by GALEX. In the NUV bandpass ($\lambda_{\rm eff} \sim 2310$z…

太阳与恒星天体物理 · 物理学 2017-05-31 Rodolfo Montez , Sofia Ramstedt , Joel H. Kastner , Wouter Vlemmings , Enmanuel Sanchez

The spectral energy distributions for pure-hydrogen (DA) hot white dwarfs can be accurately predicted by model atmospheres. This makes it possible to define spectrophotometric calibrators by scaling the theoretical spectral shapes with…

太阳与恒星天体物理 · 物理学 2015-05-13 C. Allende Prieto , I. Hubeny , J. A. Smith

The prototype of accreting, pulsating white dwarfs (GW Lib) underwent a large amplitude dwarf nova outburst in 2007. We used ultraviolet data from GALEX and ground-based optical photometry and spectroscopy to follow GW Lib for three years…

Modern large-scale surveys have allowed the identification of large numbers of white dwarfs. However, these surveys are subject to complicated target selection algorithms, which make it almost impossible to quantify to what extent the…

太阳与恒星天体物理 · 物理学 2015-06-24 A. Rebassa-Mansergas , X. -W. Liu , R. Cojocaru , H. -B. Yuan , S. Torres , E. Garcia-Berro , M. -X. Xiang , Y. Huang , D. Koester , Y. Hou , G. Li , Y. Zhang

In this work, we investigate the equilibrium structure of white dwarfs within the covariant formulation of symmetric teleparallel $f(Q)$ gravity, in which gravity is described by the nonmetricity scalar $Q$ instead of spacetime curvature.…

广义相对论与量子宇宙学 · 物理学 2026-03-24 Rajasmita Sahoo

We give an overview of the Galaxy Evolution Explorer (GALEX), a NASA Explorer Mission launched on April 28, 2003. GALEX is performing the first space UV sky-survey, including imaging and grism surveys in two bands (1350-1750 Angstroms and…

It is possible to reliably identify white dwarfs (WDs) without recourse to spectra, instead using photometric and astrometric measurements to distinguish them from Main Sequence stars and quasars. WDs' colours can also be used to infer…

天体物理学 · 物理学 2010-02-22 Daniel J. Mortlock , Hiranya V. Peiris , Zeljko Ivezic

We present deep H$\alpha$ imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5m telescope. An effective bandpass of $\sim$13\AA\ is used,…

星系天体物理 · 物理学 2016-02-17 Janice C. Lee , Sylvain Veilleux , Michael McDonald , Bryan Hilbert