Furiously fast and red: sub-second optical flaring in V404 Cyg during the 2015 outburst peak

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F16%3A00471303" target="_blank" >RIV/67985815:_____/16:00471303 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1093/mnras/stw571" target="_blank" >http://dx.doi.org/10.1093/mnras/stw571</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/stw571" target="_blank" >10.1093/mnras/stw571</a>

Result language

angličtina

Original language name

Furiously fast and red: sub-second optical flaring in V404 Cyg during the 2015 outburst peak

Original language description

We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band observations with the ULTRACAM fast imager on four nights show steep power spectra dominated by slow variations on similar to 100-1000 s time-scales. Near the peak of the outburst on June 26, a dramatic change occurs and additional, persistent sub-second optical flaring appears close in time to giant radio and X-ray flaring. The flares reach peak optical luminosities of similar to few x 10(36) erg s(-1). Some are unresolved down to a time resolution of 24 ms. Whereas the fast flares are stronger in the red, the slow variations are bluer when brighter. The redder slopes, emitted power and characteristic time-scales of the fast flares can be explained as optically thin synchrotron emission from a compact jet arising on size scales similar to 140-500 Gravitational radii (with a possible additional contribution by a thermal particle distribution). The origin of the slower variations is unclear. The optical continuum spectral slopes are strongly affected by dereddening uncertainties and contamination by strong Ha emission, but the variations of these slopes follow relatively stable loci as a function of flux. Cross-correlating the slow variations between the different bands shows asymmetries on all nights consistent with a small red skew (i.e. red lag). X-ray reprocessing and non-thermal emission could both contribute to these. These data reveal a complex mix of components over five decades in time-scale during the outburst.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

BN - Astronomy and celestial mechanics, astrophysics

OECD FORD branch

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Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

—

Volume of the periodical

459

Issue of the periodical within the volume

1

Country of publishing house

GB - UNITED KINGDOM

Number of pages

19

Pages from-to

554-572

UT code for WoS article

000376386600043

EID of the result in the Scopus database

2-s2.0-84969981437