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Your search keyword '"Horan, D."' showing total 2 results
Start Over Author "Horan, D." Topic active galaxies
2 results on '"Horan, D."'

1. VHE observations of BL Lacertae objects: 1995–2000

Author

Horan, D.

Subjects
*BL Lacertae objects, *ASTRONOMICAL observatories, *TELESCOPES, *ASTRONOMICAL instruments, *ACTIVE galaxies
Abstract

Over the past eight years, observations of BL Lacertae type objects have been an important part of the observing program at the Whipple Observatory 10 m γ-ray telescope. During this time, TeV emission was detected from five such objects: Markarian 421, Markarian 501, 1ES2344+514, H1426+428 and 1ES1959+650. Upper limits were placed on the TeV emission from 29 other BL Lacertae objects. Among these objects are two unconfirmed TeV sources, 3C66A and BL Lacertae. An overview of the results of these observations of BL Lacertae objects, between 1995 and 2000, at the Whipple Observatory is presented here. [Copyright &y& Elsevier]

Published
2004
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2. INTEGRAL and Multiwavelength Observations of the Blazar Mrk 421 during an Active Phase.

Author

Lichti, G. G., Bottacini, E., Charlot, P., Collmar, W., Horan, D., von Kienlin, A., Lähteenmäki, A., Nilsson, K., Petry, D., Sillanpää, A., Tornikoski, M., and Weekes, T.

Subjects
*BL Lacertae objects, *ACTIVE galaxies, *RADIO sources (Astronomy), *RADIO astronomy, *SPECTROMETERS, *RADIATION sources, *QUANTUM optics
Abstract

A ToO observation of the TeV-emitting blazar Mrk 421 with INTEGRAL was triggered in June 2006 by an increase of the RXTE count rate to more than 30 mCrab. The source was then observed with all INTEGRAL instruments with the exception of the spectrometer SPI for a total exposure of 829 ks. During this time several outbursts were observed by IBIS and JEM-X. Multiwavelength observations were immediately triggered and the source was observed at radio, optical and X-ray wavelengths up to TeV energies. The data obtained during these observations are analysed with respect to spectral evolution and correlated variability. Preliminary results of the analysis are presented in this poster. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2007
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