Cracking the code in the "Rosetta stone of blazars"
April 26, 2018
A team of astronomers led by Silke Britzen of the MPI für Radioastronomie in Bonn has studied in detail the multi-band emission of the binary black hole candidate blazar OJ 287 and interprets the kinematics in the parsec-scale radio jet as result from a precession in a time scale of 22 yr and a jet-axis rotation on a yearly time scale. The results suggest either the presence of a super massive binary black hole or the effect of a weird gravitometric frame-dragging effect caused by general relativity (Lense-Thirring precession). These results, based on archival data from the MOJAVE program, are presented in the present issue of the British journal Monthly Notices of the Royal Astronomical Society, and the original publication is available here.
Extreme outflows in radio-loud narrow-line Seyfert 1 galaxies
April 17, 2018
A team of astronomers led by Stefanie Komossa from the MPI für Radioastronomie in Bonn has studied four narrow-line Seyfert 1 galaxies and discovered extremely shifted spectral lines in their spectra, which indicate gas flying away from the central regions at speeds as high as 2450 km/s. These galaxies are also emitteres in the radio part of the electromagnetic spectrum. These results suggest that those galaxies are relatively young (in astronomical terms) with lifetimes of the order of magnitude of a million year. The results are published in the present issue of the journal Monthly Notices of the Royal Astronomical Society, to be found here.
New images from the Southern radio sky
February 7, 2018
An international team of astronomers led by C. Müller (Radboud U. & MPI für Radioastronomie) has published new images from a sample of southern blazars in the framework of the TANAMI program. These results are presented in the actual issue of Astronomy & Astrophysics. A powerful array of Southern telescopes located in Australia, Antarctica, Chile, New Zealand, and South Africa was assembled to obtain these unprecedented images. The TANAMI team found that that γ-ray loud sources tend to be more compact on parsec-scales and have higher brightness density in their central regions than γ-ray quiet sources. More information can be found in the original publication here.
Synthetic images from remote galaxies: understanding obscured emission
January 12, 2018
Numerical simulations performed by a team of astronomers in Frankfurt, Bonn, and Valencia led by C.M. Fromm have managed to synthesize the emission from radio objects with an obscuring torus. The numerical code Ratpenat was used to model several jets embedded in various ambient medium and torus configurations and subsequently computed their images, including jet emission and torus absorption. These simulations help understanding the physics of jets and tori, and suggets observational methods such as the core-shift to discern between different physical scenarios in the jet (e.g., if they have equal pressure inside and outside the jet, or if the pressure outside is larger). These results are shown in the present issue of the journal Astronomy & Astrophysics, for more details see here.