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A Computationally Assisted Spectroscopic Technique to measure secondary electron emission coefficients ($\gamma$-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a…

Plasma Physics · Physics 2016-06-22 M. Daksha , B. Berger , E. Schuengel , I. Korolov , A. Derzsi , M. Koepke , Z. Donko , J. Schulze

One of the most important problems in the context of cataclysmic variables (CVs) is the lack of observations of systems with periods between 2 and 3.12 hours, known as the period gap. The orbital evolution of CVs with periods shorter than…

Solar and Stellar Astrophysics · Physics 2018-11-28 C. Garraffo , J. J. Drake , J. D. Alvarado-Gomez , S. P. Moschou , O. Cohen

An XMM-Newton observation of the nearby "pre-cataclysmic" short-period (P_orb = 3.62 hr) binary QS Vir (EC 13471-1258) revealed regular narrow X-ray eclipses when the white dwarf passed behind its M2-4 dwarf companion. The X-ray emission…

Solar and Stellar Astrophysics · Physics 2015-06-03 Marco Matranga , Jeremy J. Drake , Vinay Kashyap , Danny Steeghs

We present K-band spectroscopy of short period, "sub-gap" cataclysmic variable (CV) systems obtained using ISAAC on the VLT. We show the infrared spectra (IR) for nine systems below the 2-3 hour period gap: V2051 Oph, V436 Cen, EX Hya, VW…

Solar and Stellar Astrophysics · Physics 2015-05-20 Ryan T. Hamilton , Thomas E. Harrison , Claus Tappert , Steve B. Howell

We developed a convolutional neural network (CNN) model to distinguish the double-lined spectroscopic binaries (SB2s) from others based on single exposure medium-resolution spectra ($R\sim 7,500$). The training set consists of a large set…

Using stellar models we investigate the relation between mass and the spectral type of the secondary star in low-mass short-period compact binaries such as cataclysmic variables and soft X-ray transients. Allowing for different mass…

Astrophysics · Physics 2009-10-31 U. Kolb , A. R. King , I. Baraffe

Peculiar velocity surveys, which measure galaxy peculiar velocities directly from standard candles in addition to redshifts, can provide strong constraints on the linear growth rate of cosmological large-scale structure at low redshift. The…

Multi-band photometric surveys provide a straightforward way to discover and classify astrophysical objects systematically, enabling the study of a large number of targets at relatively low cost. Here we introduce an alternative approach to…

Shear particle acceleration is a promising candidate for the origin of extended high-energy emission in extra-galactic jets. In this paper, we explore the applicability of a shear model to 24 X-ray knots in the large-scale jets of FR II…

High Energy Astrophysical Phenomena · Physics 2023-08-23 Jia-Chun He , Xiao-Na Sun , Jie-Shuang Wang , Frank M. Rieger , Ruo-Yu Liu , En-Wei Liang

The determination of fundamental parameters in low-mass X-ray binaries typically relies on measuring the radial velocity curve of the companion star through optical or near-infrared spectroscopy. It was recently suggested that high…

High Energy Astrophysical Phenomena · Physics 2018-07-25 Gabriele Ponti , Stefano Bianchi , Teo Muñoz-Darias , Kirpal Nandra

The spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been determined from a carefully established sample of 459 CVs. The sample contains all of the CVs…

Astrophysics · Physics 2008-11-26 T. Ak , S. Bilir , S. Ak , Z. Eker

The massive photometric data collected from multiple large-scale sky surveys offer significant opportunities for measuring distances of celestial objects by photometric redshifts. However, catastrophic failure is still an unsolved problem…

Instrumentation and Methods for Astrophysics · Physics 2016-05-25 Bo Han , Hongpeng Ding , Yanxia Zhang , Yongheng Zhao

The coolest dwarf stars are intrinsically faint at visible wavelengths and exhibit rotationally modulated stellar activity from spots and plages. It is advantageous to observe these stars at near infrared (NIR) wavelengths (1-2.5 microns)…

We construct a pipeline for simulating weak lensing cosmology surveys with the Square Kilometre Array (SKA), taking as inputs telescope sensitivity curves; correlated source flux, size and redshift distributions; a simple ionospheric model;…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-26 Anna Bonaldi , Ian Harrison , Stefano Camera , Michael L. Brown

CONTEXT: Combining high-contrast imaging with high-resolution spectroscopy offers a powerful way to detect and characterize exoplanets around nearby stars, despite challenges linked to their faintness. Instruments like VLT/SPHERE are state…

Instrumentation and Methods for Astrophysics · Physics 2025-04-10 S. Martos , A. Bidot , A. Carlotti , D. Mouillet

The first full year of operation following the commissioning year of the Sloan Digital Sky Survey has revealed a wide variety of newly discovered cataclysmic variables. We show the SDSS spectra of forty-two cataclysmic variables observed in…

We present spectroscopy of four cataclysmic variables. Using radial velocity measurements, we find orbital periods for the first time. The stars and their periods are GY Hya, 0.347230(9) d; SDSS J204448-045929, 1.68(1) d; V392 Hya,…

Astrophysics · Physics 2009-11-11 Christopher S. Peters , John R. Thorstensen

The orbital periods of most eclipsing cataclysmic binaries are not undergoing linear secular decreases of order a few parts per billion as expected from simple theory. Instead, they show several parts per million increases and decreases on…

Solar and Stellar Astrophysics · Physics 2021-08-18 Michael M. Shara , Steve B. Howell , Elise Furlan , Crystal L. Gnilka , Anthony F. J. Moffat , Nicholas J. Scott , David Zurek

We present the second data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities (RVs) and stellar atmosphere parameters of up to one million stars using the 6dF multi-object…

Magnetic activity strongly impacts stellar RVs and the search for small planets. We showed previously that in the solar case it induces RV variations with an amplitude over the cycle on the order of 8 m/s, with signals on short and long…

Earth and Planetary Astrophysics · Physics 2017-11-08 N. Meunier , A. -M. Lagrange , S. Borgniet
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