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Rosse Telescope

Garret Cotter

Professor of Physics

Research theme

  • Astronomy and astrophysics
  • Particle astrophysics & cosmology

Sub department

  • Astrophysics

Research groups

  • Pulsars, transients and relativistic astrophysics
  • The Square Kilometre Array (SKA)
  • Gamma-ray astronomy
Garret.Cotter@physics.ox.ac.uk
Telephone: 01865 (2)73604
Denys Wilkinson Building, room Dalitz 4
  • About
  • Publications

Synchrotron and inverse-Compton emission from blazar jets - IV. BL Lac type blazars and the physical basis for the blazar sequence

Monthly Notices of the Royal Astronomical Society 436:1 (2013) 304-314

Authors:

WJ Potter, G Cotter

Abstract:

In this paper, we investigate the properties of a sample of six BL Lacs by fitting their spectra using our inhomogeneous jet model with an accelerating, magnetically dominated, parabolic base, which transitions to a slowly decelerating conical jet with a geometry based on observations of M87. Our model is able to fit very well to the simultaneous multiwavelength spectra of all the BL Lacs including radio observations. We find that the BL Lacs have lower jet powers and bulk Lorentz factors than the sample of Compton-dominant blazars investigated in Paper III, consistent with the blazar sequence. Excitingly, we find a correlation between the radius at which the jet first comes into equipartition and the jet power, in agreement with our prediction from Paper III.We interpret this result as one of two physical scenarios: a universal jet geometry which scales linearly with black hole mass or a dichotomy in Eddington accretion rates between flat-spectrum radio quasars (FSRQs) and BL Lacs. If we assume that the jet geometry of all blazars scales linearly with black hole mass, then we find a plausible range of masses (~107-1010M⊙).We find that the quiescent gamma-ray spectrum ofMarkarian 421 is best fitted by scattering of external cosmic microwave background photons. We are unable to fit the spectrum using synchrotron self-Compton emission due to strong gamma-ray absorption via pair production even using a compact, rapidly decelerating, jet with a very large bulk Lorentz factor (50), as has been suggested recently. This is because the ratio of synchrotron to inverse-Compton emission requires a high density of synchrotron photons to scatter which makes the region opaque to TeV gamma-rays even with large bulk Lorentz factors. Finally, we fit to the spectral energy distributions of the four high power high synchrotron peak frequency BL Lacs recently found by Padovani et al. We find that their high peak frequency emission is caused by high maximum electron energies whilst the rest of their jet properties are typical of relatively high power BL Lacs and consistent with our predictions. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
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The dual-mirror small size telescope for the Cherenkov Telescope Array

Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013 2013-October (2013)

Authors:

G Pareschi, G Agnetta, LA Antonelli, D Bastieri, G Bellassai, M Belluso, S Billotta, B Biondo, G Bonanno, G Bonnoli, P Bruno, A Bulgarelli, R Canestrari, P Caraveo, A Carosi, E Cascone, O Catalano, M Cereda, P Conconi, V Conforti, G Cusumano, V de Caprio, A de Luca, A Di Paola, F Di Pierro, D Fantinel, M Fiorini, D Fugazza, D Gardiol, M Ghigo, F Gianotti, S Giarrusso, E Giro, A Grillo, D Impiombato, S Incorvaia, A la Barbera, N la Palombara, V la Parola, G la Rosa, L Lessio, G Leto, S Lombardi, F Lucarelli, MC Maccarone, G Malaguti, G Malaspina, A Mangano, V Mangano, D Marano, E Martinetti, R Millul, T Mineo, A Mistó, C Morello, MR Panzera, C Perna, G Rodeghiero, P Romano, F Russo, B Sacco, N Sartore, J Schwarz, A Segreto, G Sironi, G Sottile, E Strazzeri, L Stringhetti, G Tagliaferri, V Testa, MC Timpanaro, G Toso, G Tosti, M Trifoglio, P Vallania, S Vercellone, V Zitelli, D Dumas, P Laporte, H Sol, F de Frondat, JM Huet, JL Dournaux, JP Amans, S Blanc, G Fasola, R Fleurisson, O Hervet, I Jegouzo-Giroux, D Massol, C Rulten, F Sayede, D Savoie, A Zech, C Boisson, P Delevoye, N Ollivier, R White, J Hinton, D Ross

Abstract:

In this paper, the development of the dual mirror Small Size Telescopes (SST) for the Cherenkov Telescope Array (CTA) is reviewed. Up to 70 SST, with a primary mirror diameter of ∼ 4 m, will be produced and installed at the CTA southern site. These will allow investigation of the gamma-ray sky at the highest energies accessible to CTA, in the range from about 1 TeV to 300 TeV. The telescope presented in this contribution is characterized by two major innovations: the use of a dual mirror Schwarzschild-Couder configuration and of an innovative camera using as sensors either multi-anode photomultipliers (MAPM) or silicon photomultipliers (SiPM). The reduced plate-scale of the telescope, achieved with the dual-mirror optics, allows the camera to be compact (∼ 40 cm in diameter), and low-cost. The camera, which has about 2000 pixels of size 6×6 mm2, covers a field of view of ∼ 10◦. The dual mirror telescopes and their cameras are being developed by three consortia, ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana, Italy/INAF), GATE (Gamma-ray Telescope Elements, France/Paris Observ.) and CHEC (Compact High Energy Camera, universities in UK, US and Japan) which are merging their efforts in order to finalize an end-to-end design that will be constructed for CTA. A number of prototype structures and cameras are being developed in order to investigate various alternative designs. In this contribution, these designs are presented, along with the technological solutions under study.

Introducing the CTA concept

ASTROPARTICLE PHYSICS 43 (2013) 3-18

Authors:

BS Acharya, M Actis, T Aghajani, G Agnetta, J Aguilar, F Aharonian, M Ajello, A Akhperjanian, M Alcubierre, J Aleksic, R Alfaro, E Aliu, AJ Allafort, D Allan, I Allekotte, E Amato, J Anderson, EO Anguener, LA Antonelli, P Antoranz, A Aravantinos, T Arlen, T Armstrong, H Arnaldi, L Arrabito, K Asano, T Ashton, HG Asorey, Y Awane, H Baba, A Babic, N Baby, J Baehr, A Bais, C Baixeras, S Bajtlik, M Balbo, D Balis, C Balkowski, A Bamba, R Bandiera, A Barber, C Barbier, M Barcelo, A Barnacka, J Barnstedt, U Barres de Almeida, JA Barrio, A Basili, S Basso, D Bastieri, C Bauer, A Baushev, J Becerra, Y Becherini, KC Bechtol, J Becker Tjus, V Beckmann, W Bednarek, B Behera, M Belluso, W Benbow, J Berdugo, K Berger, F Bernard, T Bernardino, K Bernloehr, N Bhat, S Bhattacharyya, C Bigongiari, A Biland, S Billotta, T Bird, E Birsin, E Bissaldi, J Biteau, M Bitossi, S Blake, O Blanch Bigas, P Blasi, A Bobkov, V Boccone, M Boettcher, L Bogacz, J Bogart, M Bogdan, C Boisson, J Boix Gargallo, J Bolmont, G Bonanno, A Bonardi, T Bonev, P Bonifacio, G Bonnoli, P Bordas, A Borgland, J Borkowski, R Bose, O Botner, A Bottani, L Bouchet, M Bourgeat, C Boutonnet, A Bouvier, S Brau-Nogue, I Braun, T Bretz, M Briggs, T Bringmann, P Brook, P Brun, L Brunetti, T Buanes, J Buckley, R Buehler, V Bugaev, A Bulgarelli, T Bulik, G Busetto, S Buson, K Byrum, M Cailles, R Cameron, J Camprecios, R Canestrari, S Cantu, M Capalbi, P Caraveo, E Carmona, A Carosi, J Carr, P-H Carton, S Casanova, M Casiraghi, O Catalano, S Cavazzani, S Cazaux, M Cerruti, E Chabanne, P Chadwick, C Champion, A Chen, J Chiang, L Chiappetti, M Chikawa, VR Chitnis, F Chollet, J Chudoba, M Cieslar, A Cillis, J Cohen-Tanugi, S Colafrancesco, P Colin, J Calome, S Colonges, M Compin, P Conconi, V Conforti, V Connaughton, J Conrad, JL Contreras, P Coppi, P Corona, D Corti, J Cortina, L Cossio, H Costantini, G Cotter, B Courty, S Couturier, S Covino, G Crimi, SJ Criswell, J Croston, G Cusumano, M Dafonseca, O Dale, M Daniel, J Darling, I Davids, F Dazzi, A De Angelis, V De Caprio, F De Frondat, EM de Gouveia Dal Pino, I de la Calle, GA De La Vega, R de los Reyes Lopez, B De Lotto, A De Luca, JRT de Mello Neto, M de Naurois, Y de Oliveira, E de Ona Wilhelmi, V de Souza, G Decerprit, G Decock, C Deil, E Delagnes, G Deleglise, C Delgado, D Della Volpe, P Demange, G Depaola, A Dettlaff, A Di Paola, F Di Pierro, C Diaz, J Dick, R Dickherber, H Dickinson, V Diez-Blanco, S Digel, D Dimitrov, G Disset, A Djannati-Atai, M Doert, M Dohmke, W Domainko, D Dominis Prester, A Donat, D Dorner, M Doro, J-L Dournaux, G Drake, D Dravins, L Drury, F Dubois, R Dubois, G Dubus, C Dufour, D Dumas, J Dumm, D Durand, J Dyks, M Dyrda, J Ebr, E Edy, K Egberts, P Eger, S Einecke, C Eleftheriadis, S Elles, D Emmanoulopoulos, D Engelhaupt, R Enomoto, J-P Ernenwein, M Errando, A Etchegoyen, P Evans, A Falcone, D Fantinel, K Farakos, C Farnier, G Fasola, B Favill, E Fede, S Federici, S Fegan, F Feinstein, D Ferenc, P Ferrando, M Fesquet, A Fiasson, E Fillin-Martino, D Fink, C Finley, JP Finley, M Fiorini, R Firpo Curcoll, H Flores, D Florin, W Focke, C Foehr, E Fokitis, L Font, G Fontaine, M Fornasa, A Foerster, L Fortson, N Fouque, A Franckowiak, C Fransson, G Fraser, R Frei, IFM Albuquerque, L Fresnillo, C Fruck, Y Fujita, Y Fukazawa, Y Fukui, S Funk, W Gaebele, S Gabici, R Gabriele, A Gadola, N Galante, D Gall, Y Gallant, J Gamez-Garcia, B Garcia, R Garcia Lopez, D Gardiol, D Garrido, L Garrido, D Gascon, M Gaug, J Gaweda, L Gebremedhin, N Geffroy, L Gerard, A Ghedina, M Ghigo, E Giannakaki, F Gianotti, S Giarrusso, G Giavitto, B Giebels, V Gika, P Giommi, N Girard, E Giro, A Giuliani, T Glanzman, J-F Glicenstein, N Godinovic, V Golev, M Gomez Berisso, J Gomez-Ortega, MM Gonzalez, A Gonzalez, F Gonzalez, A Gonzalez Munoz, KS Gothe, M Gougerot, R Graciani, P Grandi, F Granena, J Granot, G Grasseau, R Gredig, A Green, T Greenshaw, T Gregoire, O Grimm, J Grube, M Grudzinska, V Gruev, S Gruenewald, J Grygorczuk, V Guarino, S Gunji, G Gyuk, D Hadasch, R Hagiwara, J Hahn, N Hakansson, A Hallgren, N Hamer Heras, S Hara, MJ Hardcastle, J Harris, T Hassan, K Hatanaka, T Haubold, A Haupt, T Hayakawa, M Hayashida, R Heller, F Henault, G Henri, G Hermann, R Hermel, A Herrero, N Hidaka, J Hinton, D Hoffmann, W Hofmann, P Hofverberg, J Holder, D Horns, D Horville, J Houles, M Hrabovsky, D Hrupec, H Huan, B Huber, J-M Huet, G Hughes, TB Humensky, J Huovelin, A Ibarra, JM Illa, D Impiombato, S Incorvaia, S Inoue, Y Inoue, K Ioka, E Ismailova, C Jablonski, A Jacholkowska, M Jamrozy, M Janiak, P Jean, C Jeanney, JJ Jimenez, T Jogler, T Johnson, L Journet, C Juffroy, I Jung, P Kaaret, S Kabuki, M Kagaya, J Kakuwa, C Kalkuhl, R Kankanyan, A Karastergiou, K Kaercher, M Karczewski, S Karkar, Aci Kasperek, D Kastana, H Katagiri, J Kataoka, K Katarzynski, U Katz, N Kawanaka, B Kellner-Leidel, H Kelly, E Kendziorra, B Khelifi, DB Kieda, T Kifune, T Kihm, T Kishimoto, K Kitamoto, W Kluzniak, C Knapic, JW Knapp, J Knoedlseder, F Koeck, J Kocot, K Kodani, J-H Koehne, K Kohri, K Kokkotas, D Kolitzus, N Komin, I Kominis, Y Konno, H Koeppel, P Korohoda, K Kosack, G Koss, R Kossakowski, P Kostka, R Koul, G Kowal, S Koyama, J Koziol, T Kraehenbuehl, J Krause, H Krawzcynski, F Krennrich, A Krepps, A Kretzschmann, R Krobot, P Krueger, H Kubo, VA Kudryavtsev, J Kushida, A Kuznetsov, A La Barbera, N La Palombara, V La Parola, G La Rosa, K Lacombe, G Lamanna, J Lande, D Languignon, J Lapington, P Laporte, C Lavalley, T Le Flour, A Le Padellec, S-H Lee, WH Lee, MA Leigui de Oliveira, D Lelas, J-P Lenain, DJ Leopold, T Lerch, L Lessio, B Lieunard, E Lindfors, A Liolios, A Lipniacka, H Lockart, T Lohse, S Lombardi, A Lopatin, M Lopez, R Lopez-Coto, A Lopez-Oramas, A Lorca, E Lorenz, P Lubinski, F Lucarelli, H Luedecke, J Ludwin, PL Luque-Escamilla, W Lustermann, O Luz, E Lyard, MC Maccarone, TJ Maccarone, GM Madejski, A Madhavan, M Mahabir, G Maier, P Majumdar, G Malaguti, S Maltezos, A Manalaysay, A Mancilla, D Mandat, G Maneva, A Mangano, P Manigot, K Mannheim, I Manthos, N Maragos, A Marcowith, M Mariotti, M Marisaldi, S Markoff, A Marszalek, C Martens, J Marti, J-M Martin, P Martin, G Martinez, F Martinez, M Martinez, A Masserot, A Mastichiadis, A Mathieu, H Matsumoto, F Mattana, S Mattiazzo, G Maurin, S Maxfield, J Maya, D Mazin, L Mc Comb, N McCubbin, I McHardy, R McKay, C Medina, C Melioli, D Melkumyan, S Mereghetti, P Mertsch, M Meucci, J Michalowski, P Micolon, A Mihailidis, T Mineo, M Minuti, N Mirabal, F Mirabel, JM Miranda, R Mirzoyan, T Mizuno, B Moal, R Moderski, I Mognet, E Molinari, M Molinaro, T Montaruli, I Monteiro, P Moore, A Moralejo Olaizola, M Mordalska, C Morello, K Mori, F Mottez, Y Moudden, E Moulin, I Mrusek, R Mukherjee, P Munar-Adrover, H Muraishi, K Murase, A Murphy, S Nagataki, T Naito, D Nakajima, T Nakamori, K Nakayama, C Naumann, D Naumann, M Naumann-Godo, P Nayman, D Nedbal, D Neise, L Nellen, V Neustroev, N Neyroud, L Nicastro, J Nicolau-Kuklinski, A Niedzwiecki, J Niemiec, D Nieto, A Nikolaidis, K Nishijima, S Nolan, R Northrop, D Nosek, N Nowak, A Nozato, P O'Brien, Y Ohira, M Ohishi, S Ohm, H Ohoka, T Okuda, A Okumura, J-F Olive, RA Ong, R Orito, M Orr, J Osborne, M Ostrowski, LA Otero, N Otte, E Ovcharov, I Oya, A Ozieblo, L Padilla, S Paiano, D Paillot, A Paizis, S Palanque, M Palatka, J Pallota, K Panagiotidis, J-L Panazol, D Paneque, M Panter, R Paoletti, A Papayannis, G Papyan, JM Paredes, G Pareschi, G Parks, J-M Parraud, D Parsons, M Paz Arribas, M Pech, G Pedaletti, V Pelassa, D Pelat, MDC Perez, M Persic, P-O Petrucci, B Peyaud, A Pichel, S Pita, F Pizzolato, L Platos, R Platzer, L Pogosyan, M Pohl, G Pojmanski, JD Ponz, W Potter, J Poutanen, E Prandini, J Prast, R Preece, F Profeti, H Prokoph, M Prouza, M Proyetti, I Puerto-Gimenez, G Puehlhofer, I Puljak, M Punch, R Pyziol, EJ Quel, J Quinn, A Quirrenbach, E Racero, PJ Rajda, P Ramon, R Rando, RC Rannot, M Rataj, M Raue, P Reardon, O Reimann, A Reimer, O Reimer, K Reitberger, M Renaud, S Renner, B Reville, W Rhode, M Ribo, M Ribordy, MG Richer, J Rico, J Ridky, F Rieger, P Ringegni, J Ripken, PR Ristori, A Riviere, S Rivoire, L Rob, U Roeser, R Rohlfs, G Rojas, P Romano, W Romaszkan, GE Romero, S Rosen, S Rosier Lees, D Ross, G Rouaix, J Rousselle, S Rousselle, AC Rovero, F Roy, S Royer, B Rudak, C Rulten, M Rupinski, F Russo, F Ryde, B Sacco, EO Saemann, A Saggion, V Safiakian, K Saito, T Saito, Y Saito, N Sakaki, R Sakonaka, A Salini, F Sanchez, M Sanchez-Conde, A Sandoval, H Sandaker, E Sant'Ambrogio, A Santangelo, EM Santos, A Sanuy, L Sapozhnikov, S Sarkar, N Sartore, H Sasaki, K Satalecka, M Sawada, V Scalzotto, V Scapin, M Scarcioffolo, J Schafer, T Schanz, S Schlenstedt, R Schlickeiser, T Schmidt, J Schmoll, P Schovanek, M Schroedter, C Schultz, J Schultze, A Schulz, K Schure, T Schwab, U Schwanke, J Schwarz, S Schwarzburg, T Schweizer, S Schwemmer, A Segreto, J-H Seiradakis, GH Sembroski, K Seweryn, M Sharma, M Shayduk, RC Shellard, J Shi, T Shibata, A Shibuya, E Shum, L Sidoli, M Sidz, J Sieiro, M Sikora, J Silk, A Sillanpaa, BB Singh, J Sitarek, C Skole, R Smareglia, A Smith, D Smith, J Smith, N Smith, D Sobczynska, H Sol, G Sottile, M Sowinski, F Spanier, D Spiga, S Spyrou, V Stamatescu, A Stamerra, R Starling, L Stawarz, R Steenkamp, C Stegmann, S Steiner, N Stergioulas, R Sternberger, M Sterzel, F Stinzing, M Stodulski, U Straumann, E Strazzeri, L Stringhetti, A Suarez, M Suchenek, R Sugawara, K-H Sulanke, S Sun, AD Supanitsky, T Suric, P Sutcliffe, J Sykes, M Szanecki, T Szepieniec, A Szostek, G Tagliaferri, H Tajima, H Takahashi, K Takahashi, L Takalo, H Takami, C Talbot, J Tammi, M Tanaka, S Tanaka, J Tasan, M Tavani, J-P Tavernet, LA Tejedor, I Telezhinsky, P Temnikov, C Tenzer, Y Terada, R Terrier, M Teshima, V Testa, D Tezier, D Thuermann, L Tibaldo, O Tibolla, A Tiengo, M Tluczykont, CJ Todero Peixoto, F Tokanai, M Tokarz, K Toma, K Torii, M Tornikoski, DF Torres, M Torres, G Tosti, T Totani, C Toussenel, G Tovmassian, P Travnicek, M Trifoglio, I Troyano, K Tsinganos, H Ueno, K Umehara, SS Upadhya, T Usher, M Uslenghi, JF Valdes-Galicia, P Vallania, G Vallejo, W van Driel, C van Eldik, J Vandenbrouke, J Vanderwalt, H Vankov, G Vasileiadis, V Vassiliev, D Veberic, I Vegas, S Vercellone, S Vergani, C Veyssiere, JP Vialle, A Viana, M Videla, P Vincent, S Vincent, J Vink, N Vlahakis, L Vlahos, P Vogler, A Vollhardt, H-P von Gunten, S Vorobiov, C Vuerli, V Waegebaert, R Wagner, RG Wagner, S Wagner, SP Wakely, R Walter, T Walther, K Warda, R Warwick, P Wawer, R Wawrzaszek, N Webb, P Wegner, A Weinstein, Q Weitzel, R Welsing, M Werner, H Wetteskind, R White, A Wierzcholska, S Wiesand, M Wilkinson, DA Williams, R Willingale, K Winiarski, R Wischnewski, L Wisniewski, M Wood, A Woernlein, Q Xiong, KK Yadav, H Yamamoto, T Yamamoto, R Yamazaki, S Yanagita, JM Yebras, D Yelos, A Yoshida, T Yoshida, T Yoshikoshi, V Zabalza, M Zacharias, A Zajczyk, R Zanin, A Zdziarski, A Zech, A Zhao, X Zhou, K Zietara, J Ziolkowski, P Ziolkowski, V Zitelli, C Zurbach, P Zychowski
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Synchrotron and inverse-Compton emission from blazar jets - III. Compton-dominant blazars

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 431:2 (2013) 1840-1852

Authors:

William J Potter, Garret Cotter
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Uncovering the physics behind the blazar sequence using a realistic model for jet emission

EPJ Web of Conferences EDP Sciences 61 (2013) 05008

Authors:

William J Potter, Garret Cotter
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