Gamma-ray astronomy

Research group

Research theme

Sub department

About

Radio and X-Ray Observations of the Luminous Fast Blue Optical Transient AT 2020xnd

ASTROPHYSICAL JOURNAL 926:2 (2022) ARTN 112

Authors:

Joe S Bright, Raffaella Margutti, David Matthews, Daniel Brethauer, Deanne Coppejans, Mark H Wieringa, Brian D Metzger, Lindsay DeMarchi, Tanmoy Laskar, Charles Romero, Kate D Alexander, Assaf Horesh, Giulia Migliori, Ryan Chornock, E Berger, Michael Bietenholz, Mark J Devlin, Simon R Dicker, WV Jacobson-Galan, Brian S Mason, Dan Milisavljevic, Sara E Motta, Tony Mroczkowski, Enrico Ramirez-Ruiz, Lauren Rhodes, Craig L Sarazin, Itai Sfaradi, Jonathan Sievers

MeerKAT radio detection of the Galactic black hole candidate Swift J1842.5-1124 during its 2020 outburst

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 510:1 (2022) 1258-1263

Authors:

X Zhang, W Yu, SE Motta, R Fender, P Woudt, JCA Miller-Jones, GR Sivakoff

A Late-Time Radio Flare following a Possible Transition in Accretion State in the Tidal Disruption Event AT 2019azh

(2022)

Authors:

I Sfaradi, A Horesh, R Fender, DA Green, DRA Williams, J Bright, S Schulze

Optical line spectra of tidal disruption events from reprocessing in optically thick outflows

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 510:4 (2022) 5426-5443

Authors:

Edward J Parkinson, Christian Knigge, James H Matthews, Knox S Long, Nick Higginbottom, Stuart A Sim, Samuel W Mangham

Relevance of photon-photon dispersion within the jet for blazar axionlike particle searches

Physical Review D American Physical Society 105:2 (2022) 23017

Authors:

James Davies, Garret Cotter, Manuel Meyer

Abstract:

Axionlike particles (ALPs) could mix with photons in the presence of astrophysical magnetic fields. Searching for this effect in gamma-ray observations of blazars has provided some of the strongest constraints on ALP parameter space so far. Previously, photon-photon dispersion of gamma rays off of the cosmic microwave background has been shown to be important for these calculations and is universally included in ALP-photon mixing models. Here, we assess the effects of dispersion off of other photon fields within the blazar (produced by the accretion disk, the broad line region, the dust torus, starlight, and the synchrotron field) by modeling the jet and fields of the flat spectrum radio quasar 3C454.3 and propagating ALPs through the model both with and without the full dispersion calculation. We find that the full dispersion calculation can strongly affect the mixing, particularly at energies above 100 GeV鈥攐ften reducing the ALP-photon conversion probability. This could have implications for future searches planned with, e.g., the Cherenkov Telescope Array, particularly those looking for a reduced opacity of the Universe at the highest energies.