The University of Southampton
University of Southampton Institutional Repository

The evolution of the X-ray phase lags during the outbursts of the black hole candidate GX 339–4

The evolution of the X-ray phase lags during the outbursts of the black hole candidate GX 339–4
The evolution of the X-ray phase lags during the outbursts of the black hole candidate GX 339–4
Owing to the frequency and reproducibility of its outbursts, the black hole candidate GX 339–4 has become the standard against which the outbursts of other black hole candidate are matched up. Here we present the first systematic study of the evolution of the X-ray lags of the broad-band variability component (0.008–5 Hz) in GX 339?4 as a function of the position of the source in the hardness–intensity diagram. The hard photons always lag the soft ones, consistent with previous results. In the low-hard state the lags correlate with X-ray intensity, and as the source starts the transition to the intermediate/soft states, the lags first increase faster, and then appear to reach a maximum, although the exact evolution depends on the outburst and the energy band used to calculate the lags. The time of the maximum of the lags appears to coincide with a sudden drop of the optical/near-infrared flux, the fractional rms amplitude of the broad-band component in the power spectrum, and the appearance of a thermal component in the X-ray spectra, strongly suggesting that the lags can be very useful to understand the physical changes that GX 339–4 undergoes during an outburst. We find strong evidence for a connection between the evolution of the cut-off energy of the hard component in the energy spectrum and the phase lags, suggesting that the average magnitude of the lags is correlated with the properties of the corona/jet rather than those of the disc. Finally, we show that the lags in GX 339–4 evolve in a similar manner to those of the black hole candidate Cygnus X–1, suggesting similar phenomena could be observable in other black hole systems.
1365-2966
4027-4037
Altamirano, Diego
d5ccdb09-0b71-4303-9538-05b467be075b
Mendez, Mariano
d28e6a32-ba07-4267-a01c-a349f674b3ad
Altamirano, Diego
d5ccdb09-0b71-4303-9538-05b467be075b
Mendez, Mariano
d28e6a32-ba07-4267-a01c-a349f674b3ad

Altamirano, Diego and Mendez, Mariano (2015) The evolution of the X-ray phase lags during the outbursts of the black hole candidate GX 339–4. Monthly Notices of the Royal Astronomical Society, 449 (4), 4027-4037. (doi:10.1093/mnras/stv556).

Record type: Article

Abstract

Owing to the frequency and reproducibility of its outbursts, the black hole candidate GX 339–4 has become the standard against which the outbursts of other black hole candidate are matched up. Here we present the first systematic study of the evolution of the X-ray lags of the broad-band variability component (0.008–5 Hz) in GX 339?4 as a function of the position of the source in the hardness–intensity diagram. The hard photons always lag the soft ones, consistent with previous results. In the low-hard state the lags correlate with X-ray intensity, and as the source starts the transition to the intermediate/soft states, the lags first increase faster, and then appear to reach a maximum, although the exact evolution depends on the outburst and the energy band used to calculate the lags. The time of the maximum of the lags appears to coincide with a sudden drop of the optical/near-infrared flux, the fractional rms amplitude of the broad-band component in the power spectrum, and the appearance of a thermal component in the X-ray spectra, strongly suggesting that the lags can be very useful to understand the physical changes that GX 339–4 undergoes during an outburst. We find strong evidence for a connection between the evolution of the cut-off energy of the hard component in the energy spectrum and the phase lags, suggesting that the average magnitude of the lags is correlated with the properties of the corona/jet rather than those of the disc. Finally, we show that the lags in GX 339–4 evolve in a similar manner to those of the black hole candidate Cygnus X–1, suggesting similar phenomena could be observable in other black hole systems.

Text
__soton.ac.uk_UDE_PersonalFiles_Users_skr1c15_mydocuments_REF 2021_Outputs_Astro_DiegoAltamirano_ref1.pdf - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 11 March 2015
e-pub ahead of print date: 10 April 2015
Published date: 1 June 2015
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 395578
URI: http://eprints.soton.ac.uk/id/eprint/395578
ISSN: 1365-2966
PURE UUID: f6523885-38b1-4a99-99d3-475201b547e6
ORCID for Diego Altamirano: ORCID iD orcid.org/0000-0002-3422-0074

Catalogue record

Date deposited: 01 Jun 2016 14:06
Last modified: 15 Mar 2024 03:49

Export record

Altmetrics

Contributors

Author: Mariano Mendez

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×