Upper limits from HESS active galactic nuclei observations in 2005–2007

Aims.Very high energy (VHE; $E>100$ GeV) γ-ray studies were performed for 18 active galactic nuclei (AGN) from a variety of AGN classes. Methods.VHE observations of a sample of 14 AGN, considered candidate VHE emitters, were made with the High Energy Stereoscopic System (HESS) between January 200...

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Veröffentlicht in:	Astronomy and astrophysics (Berlin) 2008-02, Vol.478 (2), p.387-393
Hauptverfasser:	Aharonian, F., Akhperjanian, A. G., Beilicke, M., Benbow, W., Bernlöhr, K., Boisson, C., Bolz, O., Borrel, V., Braun, I., Brion, E., Brown, A. M., Bühler, R., Bulik, T., Chounet, L.-M., Clapson, A. C., Coignet, G., Costamante, L., Dalton, M., Degrange, B., Djannati-Ataï, A., Domainko, W., Dubois, F., Dubus, G., Egberts, K., Emmanoulopoulos, D., Espigat, P., Farnier, C., Feinstein, F., Fiasson, A., Förster, A., Fontaine, G., Funk, S., Füßling, M., Gallant, Y. A., Giebels, B., Glicenstein, J. F., Goret, P., Hadjichristidis, C., Hauser, M., Heinzelmann, G., Henri, G., Hinton, J. A., Hoffmann, A., Hofmann, W., Hoppe, S., Horns, D., Jacholkowska, A., Jung, I., Kendziorra, E., Kerschhaggl, M., Kosack, K., Latham, I. J., Lemoine-Goumard, M., Lenain, J.-P., Lohse, T., Martin, J. M., Marcowith, A., Maurin, D., Maurin, G., McComb, T. J. L., de Naurois, M., Nedbal, D., Nolan, S. J., Ohm, S., Olive, J.-P., de Oña Wilhelmi, E., Orford, K. J., Ostrowski, M., Panter, M., Petrucci, P.-O., Pita, S., Pühlhofer, G., Punch, M., Raubenheimer, B. C., Raue, M., Renaud, M., Rob, L., Rowell, G., Rudak, B., Sahakian, V., Schöck, F., Schröder, R., Schwarzburg, S., Sol, H., Spangler, D., Stawarz, Ł., Steenkamp, R., Stegmann, C., Superina, G., Tavernet, J.-P., Terrier, R., van Eldik, C., Vasileiadis, G., Venter, C., Vialle, J. P., Vivier, M., Völk, H. J., Wagner, S. J., Ward, M., Zech, A.
Format:	Artikel
Sprache:	eng
Schlagworte:	Astronomy Astrophysics Cosmology and Extra-Galactic Astrophysics Earth, ocean, space Exact sciences and technology galaxies: active gamma rays: observations Physics Sciences of the Universe
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Zusammenfassung:	Aims.Very high energy (VHE; $E>100$ GeV) γ-ray studies were performed for 18 active galactic nuclei (AGN) from a variety of AGN classes. Methods.VHE observations of a sample of 14 AGN, considered candidate VHE emitters, were made with the High Energy Stereoscopic System (HESS) between January 2005 and July 2007. Large-zenith-angle observations of three northern AGN (Mkn 421, Mkn 501, 1ES 1218+304), known to emit VHE γ-rays, were also performed in order to sample their spectral energy distributions (SEDs) above 1 TeV. In addition, the VHE flux from 1ES 1101-232, previously detected by HESS in 2004-2005, was monitored during 2006 and 2007. Results.As significant detections from the HESS observation program are reported elsewhere, the results reported here are primarily integral flux upper limits. The average exposure for each of the 14 VHE-candidate AGN is ~7 h live time, and the observations have an average energy threshold between 230 GeV and 590 GeV. Upper limits for these 14 AGN range from
ISSN:	0004-6361 1432-0746 1432-0756
DOI:	10.1051/0004-6361:20078604