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Relativistic Jet from Black Hole

An artist's impression of a relativistic jet propagating away from a black hole at close to the speed of light. Such jets are formed by the inner regions of the accretion flow: matter flowing inwards towards the black hole, via processes which are not yet fully understood. The accretion flow emits primarily in X-rays, the relativistic jet in the radio band: by combing observations in each band we can try and understand how such jets form and how much energy they carry away from the black hole.

Professor Rob Fender

Professor of Astrophysics

Research theme

  • Astronomy and astrophysics

Sub department

  • Astrophysics

Research groups

  • Hintze Centre for Astrophysical Surveys
  • MeerKAT
  • Pulsars, transients and relativistic astrophysics
  • Rubin-LSST
  • The Square Kilometre Array (SKA)
  • Gamma-ray astronomy
Rob.Fender@physics.ox.ac.uk
Telephone: 01865 (2)73435
Denys Wilkinson Building, room 712
  • About
  • Publications

Observations of a radio-bright, X-ray obscured GRS 1915+105

(2021)

Authors:

SE Motta, JJE Kajava, M Giustini, DRA Williams, M Del Santo, R Fender, DA Green, I Heywood, L Rhodes, A Segreto, G Sivakoff, PA Woudt
More details from the publisher
Details from ArXiV

Radio flaring and dual radio loud/quiet behaviour in the new candidate black hole X-ray binary MAXI J1631-472

(2021)

Authors:

Itumeleng M Monageng, Sara E Motta, Rob Fender, Wenfei Yu, Patrick A Woudt, Evangelia Tremou, James CA Miller-Jones, Alexander J van der Horst
More details from the publisher

The science case and challenges of spaceborne sub-millimeter interferometry: the study case of TeraHertz Exploration and Zooming-in for Astrophysics (THEZA)

Proceedings of the International Astronautical Congress, IAC A7 (2021)

Authors:

LI Gurvits, Z Paragi, RI Amils, I van Bemmel, P Boven, V Casasola, J Conway, J Davelaar, MC Díez-González, H Falcke, R Fender, S Frey, CM Fromm, JD Gallego-Puyol, C García-Miró, MA Garrett, M Giroletti, C Goddi, JL Gómez, J van der Gucht, JC Guirado, Z Haiman, F Helmich, B Hudson, E Humphreys, V Impellizzeri, M Janssen, MD Johnson, YY Kovalev, M Kramer, M Lindqvist, H Linz, E Liuzzo, AP Lobanov, I López-Fernández, I Malo-Gómez, K Masania, Y Mizuno, AV Plavin, RT Rajan, L Rezzolla, F Roelofs, E Ros, KLJ Rygl, T Savolainen, K Schuster, T Venturi, H Verkouter, P de Vicente, PNAM Visser, MC Wiedner, M Wielgus, K Wiik, JA Zensus

Abstract:

Ultra-high angular resolution in astronomy has always been an important vehicle for making fundamental discoveries. Recent results in direct imaging of the vicinity of the super-massive black hole in the nucleus of the radio galaxy M87 by the millimeter VLBI system Event Horizon Telescope (EHT) and various pioneering results of the Space VLBI mission RadioAstron provided new momentum in high angular resolution astrophysics. In both mentioned cases, the angular resolution reached the values of about 10−20 microrcseconds (0.05−0.1 nanoradian). Angular resolution is proportional to the observing wavelength and inversely proportional to the interferometer baseline length. In the case of Earth-based EHT, the highest angular resolution was achieved by combining the shortest possible wavelength of 1.3 mm with the longest possible baselines, comparable to the Earth’s diameter. For RadioAstron, operational wavelengths were in the range from 92 cm down to 1.3 cm, but the baselines were as long as ∼350,000 km. However, these two highlights of radio astronomy, EHT and RadioAstron do not”saturate” the interest to further increase in angular resolution. Quite opposite: the science case for further increase in angular resolution of astrophysical studies becomes even stronger. A natural and, in fact, the only possible way of moving forward is to enhance mm/sub-mm VLBI by extending baselines to extraterrestrial dimensions, i.e. creating a mm/sub-mm Space VLBI system. The inevitable move toward space-borne mm/sub-mm VLBI is a subject of several concept studies. In this presentation we will focus on one of them called TeraHertz Exploration and Zooming-in for Astrophysics (THEZA), prepared in response to the ESA’s call for its next major science program Voyage 2050 (Gurvits et al. 2021). The THEZA rationale is focused at the physics of spacetime in the vicinity of super-massive black holes as the leading science drive. However, it will also open up a sizable new range of hitherto unreachable parameters of observational radio astrophysics and create a multi-disciplinary scientific facility and offer a high degree of synergy with prospective “single dish” space-borne sub-mm astronomy (e.g., Wiedner et al. 2021) and infrared interferometry (e.g., Linz et al. 2021). As an amalgam of several major trends of modern observational astrophysics, THEZA aims at facilitating a breakthrough in high-resolution high image quality astronomical studies.

Radio flaring and dual radio loud/quiet behaviour in the new candidate black hole X-ray binary MAXI J1631-472

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 501:4 (2021) 5776-5781

Authors:

IM Monageng, SE Motta, R Fender, W Yu, PA Woudt, E Tremou, JCA Miller-Jones, AJ van der Horst
More details from the publisher
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Measuring the distance to the black hole candidate X-ray binary MAXI J1348–630 using H I absorption

Monthly Notices of the Royal Astronomical Society: Letters Oxford University Press 501:1 (2020) L60-L64

Authors:

J Chauhan, Jca Miller-Jones, W Raja, Jr Allison, Pfl Jacob, Ge Anderson, F Carotenuto, S Corbel, Robert Fender, A Hotan, M Whiting, Pa Woudt, B Koribalski, E Mahony

Abstract:

We present neutral hydrogen (H I) absorption spectra of the black hole candidate X-ray binary (XRB) MAXI J1348–630 using the Australian Square Kilometre Array Pathfinder (ASKAP) and MeerKAT. The ASKAP H I spectrum shows a maximum negative radial velocity (with respect to the local standard of rest) of −31 ± 4 km s−1 for MAXI J1348–630, as compared to −50 ± 4 km s−1 for a stacked spectrum of several nearby extragalactic sources. This implies a most probable distance of 2.2+0.5−0.6 kpc for MAXI J1348–630, and a strong upper limit of the tangent point distance at 5.3 ± 0.1 kpc. Our preferred distance implies that MAXI J1348–630 reached 17 ± 10  per cent of the Eddington luminosity at the peak of its outburst, and that the source transited from the soft to the hard X-ray spectral state at 2.5 ± 1.5  per cent of the Eddington luminosity. The MeerKAT H I spectrum of MAXI J1348–630 (obtained from the older, low-resolution 4k mode) is consistent with the re-binned ASKAP spectrum, highlighting the potential of the eventual capabilities of MeerKAT for XRB spectral line studies.
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