is hosted by a massive elliptical galaxy typical for this class of sources. VHE gamma-ray observations of this source carried out with MAGIC between 2015 July 22 and 28 (MJD 57225–57231), were triggered when the reported HE gamma-ray daily flux, July 20 (MJD 57223), was about two times higher than the average flux reported in the 3FGL catalogue (private communication with Luigi Pacciani). The MAGIC observations led to the first detection of this source in VHE gamma rays [@2015ATel.7844....1M].

In this paper, we present the multi-frequency observations and data analysis in Section \[sec2\]. A long-term behaviour study, the comparison with other VHE gamma-ray emitting (TeV) blazars, and estimations of the source distance are presented in Section \[sec3\]. Finally, Section \[sec4\] summarizes our results.

Observations and data analysis {#sec2}
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In this section, we introduce the instruments and their respective data analysis procedures.

Very high energy gamma rays (MAGIC)
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MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes (17m diameter) located in the Canary Island of La Palma ($28.7^{\circ}$N, $17.9^{\circ}$W), at the elevation of 2200m a.s.l. [@2016APh....72...76A]. The use of the stereoscopic technique, combined with large mirror size makes MAGIC one of the most sensitive instruments for VHE gamma-ray 