Context. OJ287 is a quasar with a quasi-periodic optical light curve, with
the periodicity observed for over 120 years. This has lead to a binary black
hole model as a common explanation of the quasar. The radio jet of OJ287 has
been observed for a shorter time of about 30 years. It has a complicated
structure that varies dramatically in a few years time scale. Aims. Here we
propose that this structure arises from a helical jet being observed from a
small and varying viewing angle. The viewing angle variation is taken to be in
tune with the binary orbital motion. Methods. We calculate the effect of the
secondary black hole on the inner edge of the accretion disk of the primary
using particle simulations. We presume that the axis of the helix is
perpendicular to the disk. We then follow the jet motion on its helical path
and project the jet to the sky plane. This projection is compared with
observations both at mm waves and cm waves. Results. We find that this model
reproduces the observations well if the changes in the axis of the conical
helix propagate outwards with a relativistic speed of about 0.85c. In
particular, this model explains at the same time the long-term optical
brightness variations as varying Doppler beaming in a component close to the
core, i.e. at parsec scale in real linear distance, while the mm and cm radio
jet observations are explained as being due to jet wobble at much larger (100
parsec scale) distances from the core.
%0 Generic
%1 citeulike:12461442
%A Valtonen, Mauri
%A Pihajoki, Pauli
%D 2013
%K imported
%T A helical jet model for OJ287
%U http://arxiv.org/abs/1307.1364
%X Context. OJ287 is a quasar with a quasi-periodic optical light curve, with
the periodicity observed for over 120 years. This has lead to a binary black
hole model as a common explanation of the quasar. The radio jet of OJ287 has
been observed for a shorter time of about 30 years. It has a complicated
structure that varies dramatically in a few years time scale. Aims. Here we
propose that this structure arises from a helical jet being observed from a
small and varying viewing angle. The viewing angle variation is taken to be in
tune with the binary orbital motion. Methods. We calculate the effect of the
secondary black hole on the inner edge of the accretion disk of the primary
using particle simulations. We presume that the axis of the helix is
perpendicular to the disk. We then follow the jet motion on its helical path
and project the jet to the sky plane. This projection is compared with
observations both at mm waves and cm waves. Results. We find that this model
reproduces the observations well if the changes in the axis of the conical
helix propagate outwards with a relativistic speed of about 0.85c. In
particular, this model explains at the same time the long-term optical
brightness variations as varying Doppler beaming in a component close to the
core, i.e. at parsec scale in real linear distance, while the mm and cm radio
jet observations are explained as being due to jet wobble at much larger (100
parsec scale) distances from the core.
@misc{citeulike:12461442,
abstract = {{Context. OJ287 is a quasar with a quasi-periodic optical light curve, with
the periodicity observed for over 120 years. This has lead to a binary black
hole model as a common explanation of the quasar. The radio jet of OJ287 has
been observed for a shorter time of about 30 years. It has a complicated
structure that varies dramatically in a few years time scale. Aims. Here we
propose that this structure arises from a helical jet being observed from a
small and varying viewing angle. The viewing angle variation is taken to be in
tune with the binary orbital motion. Methods. We calculate the effect of the
secondary black hole on the inner edge of the accretion disk of the primary
using particle simulations. We presume that the axis of the helix is
perpendicular to the disk. We then follow the jet motion on its helical path
and project the jet to the sky plane. This projection is compared with
observations both at mm waves and cm waves. Results. We find that this model
reproduces the observations well if the changes in the axis of the conical
helix propagate outwards with a relativistic speed of about 0.85c. In
particular, this model explains at the same time the long-term optical
brightness variations as varying Doppler beaming in a component close to the
core, i.e. at parsec scale in real linear distance, while the mm and cm radio
jet observations are explained as being due to jet wobble at much larger (100
parsec scale) distances from the core.}},
added-at = {2019-03-25T08:20:55.000+0100},
archiveprefix = {arXiv},
author = {Valtonen, Mauri and Pihajoki, Pauli},
biburl = {https://www.bibsonomy.org/bibtex/2769602906c79fb9ed40ad9ae82418ca9/ericblackman},
citeulike-article-id = {12461442},
citeulike-linkout-0 = {http://arxiv.org/abs/1307.1364},
citeulike-linkout-1 = {http://arxiv.org/pdf/1307.1364},
day = 4,
eprint = {1307.1364},
interhash = {1201aa60b5938910ed8ae3c08b41d683},
intrahash = {769602906c79fb9ed40ad9ae82418ca9},
keywords = {imported},
month = jul,
posted-at = {2013-07-08 05:29:42},
priority = {2},
timestamp = {2019-03-25T08:20:55.000+0100},
title = {{A helical jet model for OJ287}},
url = {http://arxiv.org/abs/1307.1364},
year = 2013
}