The outburst of the blazar S4 0954+658 in 2011 March-April

Journal Article · Mon Sep 01 00:00:00 EDT 2014 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/148/3/42· OSTI ID:22342273

Morozova, D. A.; Larionov, V. M.; Troitsky, I. S.; Jorstad, S. G.; Blinov, D. A.; Efimova, N. V.; Hagen-Thorn, V. A.; Hagen-Thorn, E. I.; Konstantinova, T. S.; Kopatskaya, E. N.; Larionova, L. V.; Larionova, E. G. ^[1]; Marscher, A. P.; Joshi, M. ^[2]; Gómez, J. L. ^[3]; Lähteenmäki, A.; Tammi, J.; Rastorgueva-Foi, E.; Tornikoski, M. ^[4]; others, and

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1. Astronomical Institute of St. Petersburg State University, Universitetsky Pr. 28, Petrodvorets, 198504 St. Petersburg (Russian Federation)
2. Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215-1401 (United States)
3. Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, E-18080 Granada (Spain)
4. Aalto University Metsähovi Radio Observatory, Metsähovintie 114,FI-02540 Kylmälä (Finland)

We present the results of optical (R-band) photometric and polarimetric monitoring and Very Long Baseline Array imaging of the blazar S4 0954+658, along with Fermi γ-ray data during a multi-waveband outburst in 2011 March-April. After a faint state with a brightness level R ∼ 17.6 mag registered in the first half of 2011 January, the optical brightness of the source started to rise and reached ∼14.8 mag during the middle of March, showing flare-like behavior. The most spectacular case of intranight variability was observed during the night of 2011 March 9, when the blazar brightened by ∼0.7 mag within 7 hr. During the rise of the flux, the position angle of the optical polarization rotated smoothly over more than 300°. At the same time, within 1σ uncertainty, a new superluminal knot appeared with an apparent speed of 19.0 ± 0.3c. We have very strong evidence that this knot is associated with the multi-waveband outburst in 2011 March-April. We also analyze the multi-frequency behavior of S4 0954+658 during a number of minor outbursts from 2008 August to 2012 April. We find some evidence of connections between at least two additional superluminal ejecta and near-simultaneous optical flares.

• OSTI ID: 22342273
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 148, Issue 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BL LACERTAE OBJECTS
BRIGHTNESS
GALAXIES
PHOTOMETRY
POLARIZATION
RISE
STARS
VELOCITY
VISIBLE RADIATION