Bibcode
Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Arcaro, C.; Baack, D.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Bednarek, W.; Bernardini, E.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Carosi, R.; Ceribella, G.; Cikota, S.; Colak, S. M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Elia, V.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; Delfino, M.; Delgado, J.; di Pierro, F.; Do Souto Espiñera, E.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Elsaesser, D.; Fallah Ramazani, V.; Fattorini, A.; Fernández-Barral, A.; Ferrara, G.; Fidalgo, D.; Foffano, L.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; Gallozzi, S.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Herrera, J.; Hoang, J.; Hrupec, D.; Inoue, S.; Ishio, K.; Iwamura, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Oramas, A.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Masuda, S.; Mazin, D.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Moralejo, A.; Moreno, V.; Moretti, E.; Munar-Adrover, P. et al.
Bibliographical reference
Astronomy and Astrophysics, Volume 619, id.A159, 11 pp.
Advertised on:
11
2018
Journal
Citations
33
Refereed citations
28
Description
Context. PKS 1510-089 is a flat spectrum radio quasar strongly variable
in the optical and GeV range. To date, very high-energy (VHE, > 100
GeV) emission has been observed from this source either during long high
states of optical and GeV activity or during short flares. Aims:
We search for low-state VHE gamma-ray emission from PKS 1510-089. We
characterize and model the source in a broadband context, which would
provide a baseline over which high states and flares could be better
understood. Methods: PKS 1510-089 has been monitored by the MAGIC
telescopes since 2012. We use daily binned Fermi-LAT flux measurements
of PKS 1510-089 to characterize the GeV emission and select the
observation periods of MAGIC during low state of activity. For the
selected times we compute the average radio, IR, optical, UV, X-ray, and
gamma-ray emission to construct a low-state spectral energy distribution
of the source. The broadband emission is modeled within an external
Compton scenario with a stationary emission region through which plasma
and magnetic fields are flowing. We also perform the
emission-model-independent calculations of the maximum absorption in the
broad line region (BLR) using two different models. Results: The
MAGIC telescopes collected 75 hr of data during times when the Fermi-LAT
flux measured above 1 GeV was below 3 × 10-8
cm-2 s-1, which is the threshold adopted for the
definition of a low gamma-ray activity state. The data show a strongly
significant (9.5σ) VHE gamma-ray emission at the level of (4.27
± 0.61stat) × 10-12 cm-2
s-1 above 150 GeV, a factor of 80 lower than the highest
flare observed so far from this object. Despite the lower flux, the
spectral shape is consistent with earlier detections in the VHE band.
The broadband emission is compatible with the external Compton scenario
assuming a large emission region located beyond the BLR. For the first
time the gamma-ray data allow us to place a limit on the location of the
emission region during a low gamma-ray state of a FSRQ. For the used
model of the BLR, the 95% confidence level on the location of the
emission region allows us to place it at a distance > 74% of the
outer radius of the BLR.
Related projects
Particle Astrophysics
The MAGIC Collaboration is integrated by 20 research institutes and university departments from Armenia, Bulgaria, Finland, Germany, Italy, Poland, Spain, Switzerland and USA. The collaboration comprises two 17m diameter telescopes, located at the Roque de los Muchachos Observatory, designed to measure the Cherenkov radiation associated with
Ramón
García López
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José Antonio
Acosta Pulido