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

TL;DR

This paper reports the first detection of gamma-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations with VERITAS, revealing significant variability and enabling detailed spectral modeling.

Contribution

It demonstrates the successful use of reduced-high-voltage VERITAS observations under bright moonlight to detect VHE gamma-ray variability from a blazar for the first time.

Findings

Detected gamma-ray flare with flux five times higher than previous measurements.

Produced the first spectral energy distribution during flaring activity.

Fitted the SED with a synchrotron-self-Compton model to constrain emission region properties.

Abstract

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.