Revisiting the accretion disc spectra of Dwarf Novae and Novalike variables: implications for the standard disc model

Fuente: arXiv
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Autores principales: Zsidi, Gabriella, Nixon, C. J., Naylor, T., Pringle, J. E.
Formato: Preprint
Publicado: 2024
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author Zsidi, Gabriella
Nixon, C. J.
Naylor, T.
Pringle, J. E.
author_facet Zsidi, Gabriella
Nixon, C. J.
Naylor, T.
Pringle, J. E.
contents Accretion discs are fundamental to much of astronomy. They can occur around stars both young and old, around compact objects they provide a window into the extremes of physics, and around supermassive black holes in galaxy centres they generate spectacular luminosities that can outshine the entire galaxy. However, our understanding of the inner workings of accretion discs remains far from complete. Here we revisit a conundrum in the observations of some of the simplest accreting systems; the Cataclysmic Variables (CVs). The high-accretion-rate states of (non-magnetic) CVs can be divided into the short-lived outbursts ($\sim$ a week) typical of dwarf novae (DNe) and the long-lived (and sometimes perpetual) high states of nova-like (NL) CVs. Since both sorts of high-state occur in approximately steady-state accretion discs with similar properties and accretors, we would expect them to display similar spectral energy distributions. However, previous analyses based on UV spectra from the {\it International Ultraviolet Explorer} have shown that their spectral energy distributions are different. We perform a re-analysis of the data using up to date calibrations and distance (and thus dereddening) estimates to test whether this difference persists and whether it is statistically significant over the sample. We find that it does persist and it is statistically significant. We propose routes to investigating this discrepancy further and discuss the implications this has for other accreting systems, such as X-ray binaries, Active Galactic Nuclei and protoplanetary discs.
format Preprint
id arxiv_https___arxiv_org_abs_2406_03676
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Revisiting the accretion disc spectra of Dwarf Novae and Novalike variables: implications for the standard disc model
Zsidi, Gabriella
Nixon, C. J.
Naylor, T.
Pringle, J. E.
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Accretion discs are fundamental to much of astronomy. They can occur around stars both young and old, around compact objects they provide a window into the extremes of physics, and around supermassive black holes in galaxy centres they generate spectacular luminosities that can outshine the entire galaxy. However, our understanding of the inner workings of accretion discs remains far from complete. Here we revisit a conundrum in the observations of some of the simplest accreting systems; the Cataclysmic Variables (CVs). The high-accretion-rate states of (non-magnetic) CVs can be divided into the short-lived outbursts ($\sim$ a week) typical of dwarf novae (DNe) and the long-lived (and sometimes perpetual) high states of nova-like (NL) CVs. Since both sorts of high-state occur in approximately steady-state accretion discs with similar properties and accretors, we would expect them to display similar spectral energy distributions. However, previous analyses based on UV spectra from the {\it International Ultraviolet Explorer} have shown that their spectral energy distributions are different. We perform a re-analysis of the data using up to date calibrations and distance (and thus dereddening) estimates to test whether this difference persists and whether it is statistically significant over the sample. We find that it does persist and it is statistically significant. We propose routes to investigating this discrepancy further and discuss the implications this has for other accreting systems, such as X-ray binaries, Active Galactic Nuclei and protoplanetary discs.
title Revisiting the accretion disc spectra of Dwarf Novae and Novalike variables: implications for the standard disc model
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2406.03676