We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae (BL Lac) object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at very high energies (VHE, E > 300 GeV), the other two being Markarian 421 (Mrk 421) and Mrk 501. These three active galactic nuclei are all X-ray selected and have the lowest known redshifts of any BL Lac objects currently identified. The evidence for emission from 1ES 2344+514 comes mostly from an apparent flare on 1995 December 20 (universal date) during which a 6σ excess was detected with an average flux of I(>350 GeV) = 6.6 ± 1.9 × 10 −11 photons cm −2 s −1 . This is approximately 63% of the VHE emission from the Crab Nebula, the standard candle in this field. Observations taken between 1995 October
We report on the ␥-ray variability of Mrk 421 at E ␥ Ͼ 300 GeV during the 1995 season, and concentrate on the results of an intense multiwavelength observing campaign in the period April 20 to May 5, which included Ͼ100 MeV ␥-ray, X-ray, extreme-ultraviolet, optical, and radio observations, some of which show evidence for correlated behavior. Rapid variations in the TeV ␥-ray light curve with doubling and decay times of =1 day require a compact emission region and significant Doppler boosting. The TeV data reveal that the ␥-ray emission is best characterized by a succession of rapid flares with a relatively low baseline level of steady emission.
The division of responsibilities between different institutions in the Whipple Gamma Ray Collaboration are listed below; however these are only guidelines and the divisions are not hard and fast. The observing program is agreed upon by the collaboration in biannual meetings in which all groups are represented. The observing mode and data reduction method to be used is also agreed upon at that time. The ongoing observing program is the prime responsibility of the local Smithsonian group (aided by the resident lSU postdoc, David Bird). This involves the detailed scheduling of observing (sources and observers). Fast-look analysis is performed locally and the data is prepared for distribution to the five other centers. The local group is responsible for routine maintenance of the telescopes and cameras. Observing is shared by all groups with visiting observers sharing shifts with local staff. Responsibility for data reduction on specific sources is assumed by individuals within the collaboration. Usually students are assigned specific sources for dissertation studies. Data on each source is independently reduced by at least two observers. New data reduction methods are developed and distributed for routine analysis. Some centers take responsibility for specific tasks e.g. spectrum analysis (ISU, Leeds), periodicity analysis (Michiga;n, Leeds), etc. Technical aspects of the experiment are the responsibility of the individual groups e.g. 11m electronics (Michigan), 10m electronics (SAO), phototubes (ISU), cabling (Purdue), tracking control, ccd cameras (UCD), data acquisition software (Leeds), CAMAC interface (Purdue), data acquisition upgrades (ISU), 10m optics (SAO), 11m optics (ISU, Michigan), etc. Simulations were originally the responsibility of lSU and Leeds; they are now carried out at all centers. Long-term planning has been the responsibility of Purdue. All groups are involved in the design studies for the Phase I development. Progress Reports: Science The May 1994 Markarian Flare at Whipple and EGRET Energies Since its discovery by us at TeV energies (Punch et al. 1992), we have continued a program of monitoring the emission from Markarian 421, coordinated with observations taken by the EGRET detector. (These coordinated observations are partially supported by NASA Gamma Ray Observatory guest investigator grants.) In May 1994, an outburst was detected in which the intensity of the source increased by nearly an order-of-magnitude over its pre-outburst, "quiescent" level. A paper describing these results has now been accepted for publication in the Astrophysical Journal Letters, and a copy in included in the appendix.
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