5 year Global 3-mm VLBI survey of Gamma-ray active blazars
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2015

The Global mm-VLBI Array (GMVA) is a network of 14.3 mm and 7 mm capable telescopes spanning Europe and the United States, with planned extensions to Asia. The array is capable of sensitive maps with angular resolution often exceeding 50 μas. Using the GMVA, a large sample of prominent γ-ray blazars have been observed approximately 6 monthly from later 2008 until now. Combining 3 mm maps from the GMVA with near-in-time 7 mm maps from the VLBA-BU-BLAZAR program and 2 cm maps from the MOJAVE program, we determine the sub-pc morphology and high frequency spectral structure of γ-ray blazars. The magnetic field strength can be estimated at different locations along the jet under the assumption of equipartition between magnetic field and relativistic particle energies. Making assumptions on the jet magnetic field configuration (e.g. poloidal or toroidal), we can estimate the separation of the mm-wave “core” and the jet base, and estimate the strength of the magnetic field there. The results of this analysis show that on average, the magnetic field strength decreases with a power-law (B proportional to r^(−n), with n = 0.3 +/- 0.2). This suggests that on average, the mm-wave “core” is ∼ 1 − 3 pc downstream of the deprojected jet apex and that the magnetic field strength is of the order B apex ∼ 5 − 20 kG, broadly consistent with the predictions of magnetic jet launching (e.g. via magnetically arrested disks, MAD).

Författare

J. Hodgson

Max Planck-institutet

T. P. Krichbaum

Max Planck-institutet

A. Marscher

Boston University

S.G. Jorstad

Boston University

Ivan Marti-Vidal

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Michael Lindqvist

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

M. Bremer

Institut de RadioAstronomie Millimetrique (IRAM)

S. Sanchez

Institut de RadioAstronomie Millimetrique (IRAM)

P. de Vicente

Yebes Astronomical Observatory

A.J. Zensus

Max Planck-institutet

Proceedings of 12th European VLBI Network Symposium and Users Meeting

1824-8039 (eISSN)

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

Infrastruktur

Onsala rymdobservatorium