The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

Journal
Date Issued
2021
Author(s)
•
•
Carosati, D
•
Benítez, E
•
Kurtanidze, S O
•
Gupta, A C
•
Mirzaqulov, D O
•
•
Larionov, V M
•
Pursimo, T
•
Acosta-Pulido, J A
•
Baida, G V
•
•
Bonnoli, G
•
Borman, G A
•
•
Chen, W-P
•
Dhiman, V
•
Di Maggio, A
•
Ehgamberdiev, S A
•
Hiriart, D
•
Kimeridze, G N
•
Kurtanidze, O M
•
Lin, C S
•
Lopez, J M
•
Marchini, A
•
Matsumoto, K
•
Mujica, R
•
Nakamura, M
•
Nikiforova, A A
•
Nikolashvili, M G
•
Okhmat, D N
•
Otero-Santos, J
•
Rizzi, N
•
Sakamoto, T
•
Semkov, E
•
Sigua, L A
•
Stiaccini, L
•
Troitsky, I S
•
Tsai, A L
•
Vasilyev, A A
•
Zhovtan, A V
DOI
Abstract
Blazar S5 0716+714 is well-known for its short-term variability, down to intraday time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December-2020 January and analyse the object fast variability with unprecedented sampling. Supporting observations by the Whole Earth Blazar Telescope Collaboration in B, V, R, and I bands allow us to investigate the spectral variability during the TESS pointing. The spectral analysis is further extended in frequency to the UV and X-ray bands with data from the Neil Gehrels Swift Observatory. We develop a new method to unveil the shortest optical variability time-scales. This is based on progressive de-trending of the TESS light curve by means of cubic spline interpolations through the binned fluxes, with decreasing time bins. The de-trended light curves are then analysed with classical tools for time-series analysis (periodogram, autocorrelation, and structure functions). The results show that below 3 d there are significant characteristic variability time-scales of about 1.7, 0.5, and 0.2 d. Variability on time-scales $\lesssim 0.2$ d is strongly chromatic and must be ascribed to intrinsic energetic processes involving emitting regions, likely jet substructures, with dimension less than about 10-3 pc. In contrast, flux changes on time-scales $\gtrsim 0.5$ d are quasi-achromatic and are probably due to Doppler factor changes of geometric origin.
Volume
501
Issue
1
Start page
1100
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2021MNRAS.501.1100R
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

staa3561.pdf

Description
Pdf editoriale
Size

4.16 MB

Format

Adobe PDF

Checksum (MD5)

4828e998e03d8deff57738a964d2232f