Gamma-ray astronomy

Research group

Research theme

Sub department

About

Differential Frequency-dependent Delay from the Pulsar Magnetosphere

(2013)

Authors:

TE Hassall, BW Stappers, P Weltevrede, JWT Hessels, A Alexov, T Coenen, A Karastergiou, M Kramer, EF Keane, VI Kondratiev, J van Leeuwen, A Noutsos, M Pilia, M Serylak, C Sobey, K Zagkouris, R Fender, ME Bell, J Broderick, J Eisloffel, H Falcke, J-M Griessmeier, M Kuniyoshi, JCA Miller-Jones, MW Wise, O Wucknitz, P Zarka, A Asgekar, F Batejat, MJ Bentum, G Bernardi, P Best, A Bonafede, F Breitling, M Bruggen, HR Butcher, B Ciardi, F de Gasperin, J-P de Reijer, S Duscha, RA Fallows, C Ferrari, W Frieswijk, MA Garrett, AW Gunst, G Heald, M Hoeft, E Juette, P Maat, JP McKean, MJ Norden, M Pandey-Pommier, R Pizzo, AG Polatidis, W Reich, H Rottgering, J Sluman, Y Tang, C Tasse, R Vermeulen, RJ van Weeren, SJ Wijnholds, S Yatawatta
More details from the publisher

Automated rapid follow-up of swift Gamma-ray burst alerts at 15 GHz with the AMI large array

Monthly Notices of the Royal Astronomical Society 428:4 (2013) 3114-3120

Authors:

TD Staley, DJ Titterington, RP Fender, JD Swinbank, AJ van der Horst, A Rowlinson, AMM Scaife, KJB Grainge, GG Pooley

Abstract:

We present 15-GHz follow-up radio observations of 11 Swift gamma-ray burst (GRB) sources, obtained with theArcminute Microkelvin Imager LargeArray (AMI-LA). The initial follow-up observation for each sourcewas made in a fully automated fashion; as a result four observations were initiated within 5 min of the GRB alert time stamp. These observations provide the first millijansky-level constraints on prolonged radio emission from GRBs within the first hour post-burst. While no radio emission within the first six hours after the GRB is detected in this preliminary analysis, radio afterglow is detected from one of the GRBs (GRB 120326A) on a time-scale of days. The observations were made as part of an ongoing programme to use AMI-LA as a systematic follow-up tool for transients at radio frequencies. In addition to the preliminary results, we explain how we have created an easily extensible automated follow-up system, describing new software tools developed for astronomical transient alert distribution, automatic requesting of target-of-opportunity observations and robotic control of the observatory. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
More details from the publisher
More details
Details from ArXiV

Interpretation of the depths of maximum of extensive air showers measured by the Pierre Auger Observatory

Journal of Cosmology and Astroparticle Physics IOP Publishing 2013:02 (2013) 026-026
More details from the publisher
Details from ArXiV

Observational constraints on the powering mechanism of transient relativistic jets

(2013)

Authors:

DM Russell, E Gallo, RP Fender
More details from the publisher

Synchronous x-ray and radio mode switches: a rapid global transformation of the pulsar magnetosphere.

Science 339:6118 (2013) 436-439

Authors:

W Hermsen, JWT Hessels, L Kuiper, J van Leeuwen, D Mitra, J de Plaa, JM Rankin, BW Stappers, GAE Wright, R Basu, A Alexov, T Coenen, J-M Grießmeier, TE Hassall, A Karastergiou, E Keane, VI Kondratiev, M Kramer, M Kuniyoshi, A Noutsos, M Serylak, M Pilia, C Sobey, P Weltevrede, K Zagkouris, A Asgekar, IM Avruch, F Batejat, ME Bell, MR Bell, MJ Bentum, G Bernardi, P Best, L Bîrzan, A Bonafede, F Breitling, J Broderick, M Brüggen, HR Butcher, B Ciardi, S Duscha, J Eislöffel, H Falcke, R Fender, C Ferrari, W Frieswijk, MA Garrett, F de Gasperin, E de Geus, AW Gunst, G Heald, M Hoeft, A Horneffer, M Iacobelli, G Kuper, P Maat, G Macario, S Markoff, JP McKean, M Mevius, JCA Miller-Jones, R Morganti, H Munk, E Orrú, H Paas, M Pandey-Pommier, VN Pandey, R Pizzo, AG Polatidis, S Rawlings, W Reich, H Röttgering, AMM Scaife, A Schoenmakers, A Shulevski, J Sluman, M Steinmetz, M Tagger, Y Tang, C Tasse, S ter Veen, R Vermeulen, RH van de Brink, RJ van Weeren, RAMJ Wijers, MW Wise, O Wucknitz, S Yatawatta, P Zarka

Abstract:

Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-"bright" mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-"quiet" mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.
More details from the publisher
More details