CaltechAUTHORS
Published December 2017 | Version Submitted + Published
Journal Article Open

Optical EVPA rotations in blazars: testing a stochastic variability model with RoboPol data

Creators

  • 1. ROR icon Aalto University
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon University of Crete
  • 4. ROR icon St Petersburg University
  • 5. ROR icon Foundation for Research and Technology Hellas
  • 6. ROR icon Stanford University

Abstract

We identify rotations of the polarization angle in a sample of blazars observed for three seasons with the RoboPol instrument. A simplistic stochastic variability model is tested against this sample of rotation events. The model is capable of producing samples of rotations with parameters similar to the observed ones, but fails to reproduce the polarization fraction at the same time. Even though we can neither accept nor conclusively reject the model, we point out various aspects of the observations that are fully consistent with a random walk process.

Additional Information

© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 August 17. Received 2017 August 16; in original form 2017 June 8. Published: 23 August 2017. The RoboPol project is a collaboration between the University of Crete/FORTH in Greece, Caltech in the USA, MPIfR in Germany, IUCAA in India and Toruń Centre for Astronomy in Poland. This research was supported in part by NASA grants NNX11A043G and NNX16AR41G and NSF grant AST-1109911. SK is supported through NASA grant NNX13AQ89G. This research was partly funded by the Academy of Finland project 284495. SK particularly thanks T. Savolainen for comments on this manuscript and for the support of this research. The authors furthermore thank E. Angelakis, T. Hovatta, V. Pavlidou and K. Tassis from the RoboPol collaboration for comments and intense discussions during the collaboration meetings. This research was done with PYTHON packages NUMPY 1.11.3—, SCIPY 0.18.1—, STATSMODELS 0.6.1—, PYTABLES 3.3.0— and MATPLOTLIB 2.0.0—.

Attached Files

Published - stx2167.pdf

Submitted - 1708.06777.pdf

Files

1708.06777.pdf

Files (10.9 MB)

Name Size
md5:9af52ca23513305c18e58ce517bc5b3c
7.3 MB Preview Download
md5:f1e1ee4330bf73847217a6ce776d46ae
3.6 MB Preview Download

Additional details

Identifiers

Eprint ID
82919
Resolver ID
CaltechAUTHORS:20171102-160804515

Related works

Describes
https://arxiv.org/abs/1708.06777 (URL)

Funding

NASA
NNX11A043G
NASA
NNX16AR41G
NSF
AST-1109911
NASA
NNX13AQ89G
Academy of Finland
284495

Dates

Created
2017-11-03
Created from EPrint's datestamp field
Updated
2021-11-15
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Owens Valley Radio Observatory