The high-peaked BL Lac object 1ES 0647+250 is one of the few distant blazars detected at very- high-energy (VHE, 𝐸 > 100 GeV) 𝛾 rays during non-flaring activity. Its redshift is still uncertain, with a recently proposed lower limit of 𝑧 > 0.29. This blazar was first detected by the MAGIC telescopes between 2009 and 2011 during its low state, displaying a flux of around 2% of the Crab Nebula above 100 GeV, but it has shown several periods of high activity, where the VHE 𝛾-ray flux increased by more than one order of magnitude. The VHE spectra of four observed periods are characterized and the redshift of this source is estimated using the HE and VHE spectral shapes. The multi-wavelength data set collected from 2009 to 2020 introduced in this work will serve as the seed for further studies, including detailed studies of the broad-band spectral energy distribution for different activity levels and multi-band variability and correlation studies.
BL Lac object 1ES 0647+250, a decade of MWL observations
Longo, Francesco;Prada Moroni, Pier Giorgio;Ventura, Sofia;
2022-01-01
Abstract
The high-peaked BL Lac object 1ES 0647+250 is one of the few distant blazars detected at very- high-energy (VHE, 𝐸 > 100 GeV) 𝛾 rays during non-flaring activity. Its redshift is still uncertain, with a recently proposed lower limit of 𝑧 > 0.29. This blazar was first detected by the MAGIC telescopes between 2009 and 2011 during its low state, displaying a flux of around 2% of the Crab Nebula above 100 GeV, but it has shown several periods of high activity, where the VHE 𝛾-ray flux increased by more than one order of magnitude. The VHE spectra of four observed periods are characterized and the redshift of this source is estimated using the HE and VHE spectral shapes. The multi-wavelength data set collected from 2009 to 2020 introduced in this work will serve as the seed for further studies, including detailed studies of the broad-band spectral energy distribution for different activity levels and multi-band variability and correlation studies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.