Abstract for Proposal 089100

DEEP INVESTIGATIONS OF THE SPECTRAL BUMP OF MKR 501

With the proposed project, we aim at studying the feature in the VHE spectrum of Mrk 501 in detail. Evidence for a bump in the spectrum was found in data from observations in July 2014. We would like to study with MAGIC, if the spectral bump re-appears, and if it does, characterize it with respect to its time duration, position, intensity and width. Defining criteria independent of the VHE to identify the feature, data from more observations can be combined yielding a more significant detection. Furthermore characterizing the properties of the bump and their potential variations, one could rule out or constrain the theoretical models predicting narrow features in the VHE spectra of blazars. Given the short duration and moderate flux of 1-2 Crab Units seen during the 2014 observations showing the bump, we plan to trigger observations MAGIC observations within the same night based on the FACT monitoring benefiting from the unique situation of having two IACTs in the same location.



Details on Observing Strategy and Trigger Criteria
The trigger will happen based on the FACT monitoring programm: When the flux of Mrk501 reaches more than 1.5 CU at TeV energies (1 CU is the flux of the Crab Nebula), we will trigger both MAGIC and XMM-Newton. MAGIC will then observe 3x2 hours - the first observation will start immediately, the second will happen in the next night and the third in the night after, so that we will follow the spectral behaviour of the source with MAGIC for 3 nights. The goal for the XMM-Newton observation is to have it simultaneous with at least one of the MAGIC observations.