The temporal characteristics of the TeV gamma-emission from Mkn 501 in 1997 II. Results from HEGRA CT1 and CT2

Citation
F. Aharonian et al., The temporal characteristics of the TeV gamma-emission from Mkn 501 in 1997 II. Results from HEGRA CT1 and CT2, ASTRON ASTR, 349(1), 1999, pp. 29-44
Citations number
24
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
349
Issue
1
Year of publication
1999
Pages
29 - 44
Database
ISI
SICI code
0004-6361(199909)349:1<29:TTCOTT>2.0.ZU;2-P
Abstract
We present the results on the TeV gamma emission from Mkn 501 in 1997 obtai ned with the stand-alone Cherenkov telescopes CT1 and CT2 (threshold greate r than or equal to 1.2 and greater than or equal to 1.0 resp.) of the HEGRA collaboration. The CTI lightcurve has the most complete coverage of all Te V observations of Mkn 501 in 1997 due to the additional observations made u nder the presence of moonlight. CT2 - at the time of these observations a s econd generation Cherenkov telescope with relatively low imaging resolution - is a well tested instrument and its 85 hours of observational data on Mk n 501 in 1997 are useful for consistency checks and provide some additional daily data points. The Mkn 501 lightcurve data show significant correlatio n with the RXTE ASM X-ray data consistent with no time-lag. The spectral an alysis shows a steepening spectrum extending beyond 10 TeV. No change of th e spectral slope with the variation of the intensity was found. The results presented here are consistent with the results from the HEGRA Cherenkov te lescope system presented in part I of this paper.