Search for VHE gamma-ray emission from Geminga pulsar and nebula with the MAGIC telescopes

Abstract

The Geminga pulsar, one of the brighest gamma-ray sources, is a promising candidate for emission of very-high-energy (VHE > 100 GeV) pulsed gamma rays. Also, detection of a large nebula have been claimed by water Cherenkov instruments. We performed deep observations of Geminga with the MAGIC telescopes, yielding 63 hours of good-quality data, and searched for emission from the pulsar and pulsar wind nebula. We did not find any significant detection, and derived 95% confidence level upper limits. The resulting upper limits of 5.3 x 10^{-13} TeV cm^{-2} s^{-1} for the Geminga pulsar and 3.5 x 10^{-12} TeV cm^{-2} s^{-1} for the surrounding nebula at 50 GeV are the most constraining ones obtained so far at VHE. To complement the VHE observations, we also analyzed 5 years of Fermi-LAT data from Geminga, finding that the sub-exponential cut-off is preferred over the exponential cut-off that has been typically used in the literature. We also find that, above 10 GeV, the gamma-ray spectra from Geminga can be described with a power law with index softer than 5. The extrapolation of the power-law Fermi-LAT pulsed spectra to VHE goes well below the MAGIC upper limits, indicating that the detection of pulsed emission from Geminga with the current generation of Cherenkov telescopes is very difficult.

8 pages, 6 figures

References in corpus (13)

• TEMPO2, a new pulsar timing package. I: Overview
• The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula
• 2FHL: The Second Catalog of Hard Fermi-LAT Sources
• The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the system
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• Milagro Observations of Multi-TeV Emission from Galactic Sources in the Fermi Bright Source List
• Teraelectronvolt pulsed emission from the Crab pulsar detected by MAGIC
• Synchrotron Self-Compton Emission from the Crab and Other Pulsars
• High-energy Emission from Pulsar Magnetospheres
• Three-dimensional non-vacuum pulsar outer-gap model: Localized acceleration electric field in the higher altitudes
• Modeling of the gamma-ray pulsed spectra of Geminga, Crab, and Vela with synchro-curvature radiation
• A Search for Pulsations from Geminga Above 100 GeV with VERITAS
• A systematic synchro-curvature modelling of pulsar $\gamma$-ray spectra unveils hidden trends

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• Gamma-ray halos around pulsars as the key to understanding cosmic ray transport in the Galaxy
• Constraining the properties of the magnetic turbulence in the Geminga region using HAWC $\gamma$-ray data
• Cosmic-Ray Propagation in Light of Recent Observation of Geminga
• Detection of the Geminga pulsar with MAGIC hints at a power-law tail emission beyond 15 GeV
• First Ground-based Measurement of Sub-20 GeV to 100 GeV $\gamma$-rays from the Vela Pulsar with H.E.S.S. II
• Detection of extended gamma-ray emission around the Geminga pulsar with H.E.S.S
• Prospects for a survey of the Galactic plane with the Cherenkov Telescope Array
• Prospects for the detection of high-energy (E>25 GeV) Fermi pulsars with the Cherenkov Telescope Array
• A Search for Pulsed Very High-Energy Gamma Rays from Thirteen Young Pulsars in Archival VERITAS Data
• TeV Gamma Rays From Galactic Center Pulsars
• A mechanism-independent methodology for modeling γ-ray phaseograms of pulsars in the framework of north-south symmetry
• On Integral Upper Limits Assuming Power Law Spectra and the Sensitivity in High-Energy Astronomy
• A GMRT 610 MHz radio survey of the North Ecliptic Pole (NEP, ADF-N) / Euclid Deep Field North