Accretion flows in nonmagnetic white dwarf binaries as observed in X-rays
| Autor: | Solen Balman |
|---|---|
| Přispěvatelé: | Balman, Şölen |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Thermal emission
Atmospheric Science Accretion 010504 meteorology & atmospheric sciences Astrophysics::High Energy Astrophysical Phenomena Population FOS: Physical sciences Aerospace Engineering Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Non-thermal emission X-rays: binaries Accretion disc 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics education 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences High Energy Astrophysical Phenomena (astro-ph.HE) Physics Cataclysmic variables education.field_of_study Advection White dwarf White dwarfs Astronomy and Astrophysics Gas dynamics Accretion (astrophysics) Geophysics Space and Planetary Science Accretion disks General Earth and Planetary Sciences Outflow Astrophysical plasma Astrophysics::Earth and Planetary Astrophysics Astrophysics - High Energy Astrophysical Phenomena |
| Popis: | Cataclysmic Variables (CVs) are compact binaries with white dwarf (WD) primaries. CVs and other accreting WD binaries (AWBs) are useful laboratories for studying accretion flows, gas dynamics, outflows, transient outbursts, and explosive nuclear burning under different astrophysical plasma conditions. They have been studied over decades and are important for population studies of galactic X-ray sources. Recent space- and ground-based high resolution spectral and timing studies, along with recent surveys indicate that we still have observational and theoretical complexities yet to answer. I review accretion in nonmagnetic AWBs in the light of X-ray observations. I present X-ray diagnostics of accretion in dwarf novae and the disk outbursts, the nova-like systems, and the state of the research on the disk winds and outflows in the nonmagnetic CVs together with comparisons and relations to classical and recurrent nova systems, AM CVns and Symbiotic systems. I discuss how the advective hot accretion flows (ADAF-like) in the inner regions of accretion disks (merged with boundary layer zones) in nonmagnetic CVs explain most of the discrepancies and complexities that have been encountered in the X-ray observations. I stress how flickering variability studies from optical to X-rays can be probes to determine accretion history and disk structure together with how the temporal and spectral variability of CVs are related to that of LMXBs and AGNs. Finally, I discuss the nature of accretion in nonmagnetic WDs in terms of ADAF-like accretion flows, and elaborate on the solutions it brings and its complications, constructing an observational framework to motivate new theoretical calculations that introduce this flow-type in disks, outflow and wind models together with disk-instability models of outbursts and nova outbursts in AWBs and WD physics, in general. Comment: 24 pages, 8 figures, 1 Table, the content of this paper is Published (in Press) in a Special Issue of Advances in Space Research, entitled "Nova Eruptions, Cataclysmic Variables and Related Systems: Challenges in the 2020 Era", edited by Solen Balman |
| Databáze: | OpenAIRE |
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