VERITAS detection of gamma-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations

During May 2013, a gamma-ray flare from the BL Lac object 1ES 1727+502 (z=0.055) has been detected with the VERITAS Cherenkov telescopes. This detection represents the first evidence of very-high-energy (E>100 GeV) variability from this blazar and has been achieved using a reduced-high-voltage configuration which allows observations under bright moonlight. The integral flux is about five times higher than the archival VHE flux measured by MAGIC. The detection triggered additional VERITAS observations during standard dark-time and multiwavelength observations from infrared to X-rays with the FLWO 48" telescope and the Swift satellite. The results from this campaign are presented and used to produce the first spectral energy distribution of this object during gamma-ray flaring activity. The spectral energy distribution is then fit with a standard synchrotron-self-Compton model, placing constraints on the properties of the emitting region in the blazar.Comment: 8 pages, 3 figures; to appear in the Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. This paper summarizes the results presented in ApJ, 808, 110 (arXiv:1506.06246

Random Field Potts model with dipolar-like interactions: hysteresis, avalanches and microstructure

A model for the study of hysteresis and avalanches in a first-order phase transition from a single variant phase to a multivariant phase is presented. The model is based on a modification of the Random Field Potts model with metastable dynamics by adding a dipolar interaction term truncated at nearest neighbors. We focus our study on hysteresis loop properties, on the three-dimensional (3D) microstructure formation and on avalanche statistics.Comment: 11 pages, 16 figure

Squaring the magic squares of order 4

In this paper, we present the problem of counting magic squares and we focus on the case of multiplicative magic squares of order 4. We give the exact number of normal multiplicative magic squares of order 4 with an original and complete proof, pointing out the role of the action of the symmetric group. Moreover, we provide a new representation for magic squares of order 4. Such representation allows the construction of magic squares in a very simple way, using essentially only five particular 4X4 matrices