Multiwavelength observations of the previously unidentified blazar RX J0648.7+1516

We report on the VERITAS discovery of very high energy (VHE) gamma-ray emission above 200GeV from the high-frequency-peaked BL Lac (HBL) object RXJ0648.7+1516 (GBJ0648+1516), associated with 1FGLJ0648.8+1516. The photon spectrum above 200GeV is fitted by a power law dN/dE = F 0(E/E 0)-Γ with a photo...

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Detalles Bibliográficos
Autores principales: Aliu, E., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Bouvier, A., Bradbury, S.M., Buckley, J.H., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Connolly, M.P., Cui, W., Decerprit, G., Dickherber, R., Duke, C., Errando, M., Falcone, A., Feng, Q., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G.H., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Hivick, B., Holder, J., Huan, H., Hughes, G., Hui, C.M., Humensky, T.B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., Ong, R.A., Orr, M., Otte, A.N., Park, N., Perkins, J.S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L.C., Reynolds, P.T., Roache, E., Rose, H.J., Ruppel, J., Saxon, D.B., Sembroski, G.H., Skole, C., Smith, A.W., Staszak, D., Teišić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V.V., Wakely, S.P., Weekes, T.C., Weinstein, A., Williams, D.A., Zitzer, B., Ciprini, S., Fumagalli, M., Kaplan, K., Paneque, D., Prochaska, J.X.
Formato: JOUR
Materias:
gamma rays: galaxies
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0004637X_v742_n2_p_Aliu
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:We report on the VERITAS discovery of very high energy (VHE) gamma-ray emission above 200GeV from the high-frequency-peaked BL Lac (HBL) object RXJ0648.7+1516 (GBJ0648+1516), associated with 1FGLJ0648.8+1516. The photon spectrum above 200GeV is fitted by a power law dN/dE = F 0(E/E 0)-Γ with a photon index Γ of 4.4 ± 0.8stat± 0.3syst and a flux normalization F 0 of (2.3± 0.5stat± 1.2sys) × 10-11TeV-1cm-2 s-1 with E 0 = 300GeV. No VHE variability is detected during VERITAS observations of RXJ0648.7+1516 between 2010 March 4 and April 15. Following the VHE discovery, the optical identification and spectroscopic redshift were obtained using the Shane 3 m Telescope at the Lick Observatory, showing the unidentified object to be a BL Lac type with a redshift of z = 0.179. Broadband multiwavelength observations contemporaneous with the VERITAS exposure period can be used to subclassify the blazar as an HBL object, including data from the MDM observatory, Swift-UVOT, and X-Ray Telescope, and continuous monitoring at photon energies above 1GeV from the Fermi Large Area Telescope (LAT). We find that in the absence of undetected, high-energy rapid variability, the one-zone synchrotron self-Compton (SSC) model overproduces the high-energy gamma-ray emission measured by the Fermi-LAT over 2.3 years. The spectral energy distribution can be parameterized satisfactorily with an external-Compton or lepto-hadronic model, which have two and six additional free parameters, respectively, compared to the one-zone SSC model. © 2011. The American Astronomical Society. All rights reserved.

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