Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode

Abstract

The nearby elliptical galaxy M87 contains one of the only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to gamma-ray energies) took part in the second M87 EHT campaign. The goal of this extensive MWL campaign was to better understand the physics of the accreting black hole M87*, the relationship between the inflow and inner jets, and the high-energy particle acceleration. Understanding the complex astrophysics is also a necessary first step towards performing further tests of general relativity. The MWL campaign took place in April 2018, overlapping with the EHT M87* observations. We present a new, contemporaneous spectral energy distribution (SED) ranging from radio to very high energy (VHE) gamma-rays, as well as details of the individual observations and light curves. We also conduct phenomenological modelling to investigate the basic source properties. We present the first VHE gamma-ray flare from M87 detected since 2010. The flux above 350 GeV has more than doubled within a period of about 36 hours. We find that the X-ray flux is enhanced by about a factor of two compared to 2017, while the radio and millimetre core fluxes are consistent between 2017 and 2018. We detect evidence for a monotonically increasing jet position angle that corresponds to variations in the bright spot of the EHT image. Our results show the value of continued MWL monitoring together with precision imaging for addressing the origins of high-energy particle acceleration. While we cannot currently pinpoint the precise location where such acceleration takes place, the new VHE gamma-ray flare already presents a challenge to simple one-zone leptonic emission model approaches, and emphasises the need for combined image and spectral modelling.

46 pages, 23 figures, accepted by Astronomy & Astrophysics on August. 29, 2024

References in corpus (77)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Observations of the Crab Nebula with H.E.S.S
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula
• Fast TeV variability in blazars: jets in a jet
• Formation of Hard Power-laws in the Energetic Particle Spectra Resulting from Relativistic Magnetic Reconnection
• First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole
• Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
• First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• Background Modelling in Very-High-Energy gamma-ray Astronomy
• Fast variability of TeV gamma-rays from the radio galaxy M 87
• Relativistic Jets Shine through Shocks or Magnetic Reconnection?
• Synchrotron Self-Compton Analysis of TeV X-ray Selected BL Lacertae Objects
• The First VERITAS Telescope
• Imfit: A Fast, Flexible New Program for Astronomical Image Fitting
• Black hole flares: ejection of accreted magnetic flux through 3D plasmoid-mediated reconnection
• Kinematics of the jet in M87 on scales of 100 -- 1000 Schwarzschild radii
• The Inner Jet of the Radio Galaxy M87
• Dynamics and High Energy Emission of the Flaring HST-1 Knot in the M 87 Jet
• Blazar flares powered by plasmoids in relativistic reconnection
• Gamma-Hadron Separation in Very-High-Energy gamma-ray astronomy using a multivariate analysis method
• A ring-like accretion structure in M87 connecting its black hole and jet
• Variable TeV emission as a manifestation of jet formation in M87?
• Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
• 3D Relativistic Magnetohydrodynamic Simulations of Magnetized Spine-Sheath Relativistic Jets
• Particle acceleration in the driven relativistic reconnection
• Precessing jet nozzle connecting to a spinning black hole in M87
• Superorbital variability of X-ray and radio emission of Cyg X-1 - II. Dependence of the orbital modulation and spectral hardness on the superorbital phase
• Observation of gamma-ray emission from the galaxy M87 above 250 GeV with VERITAS
• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• State-of-the-art energetic and morphological modelling of the launching site of the M87 jet
• A synchrotron self-Compton scenario for the very high energy gamma-ray emission of the radiogalaxy M87
• Kinematics of the M87 jet in the collimation zone: gradual acceleration and velocity stratification
• Fermi Large Area Telescope Performance After 10 Years Of Operation
• Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope
• The ALMA Phasing System: A Beamforming Capability for Ultra-High-Resolution Science at (Sub)Millimeter Wavelengths
• Radiative reconnection-powered TeV flares from the black hole magnetosphere in M87
• Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
• A strong radio brightening at the jet base of M87 during the elevated very-high-energy gamma-ray state in 2012
• Calibration of ALMA as a phased array: ALMA observations during the 2017 VLBI campaign
• Towards simulating and quantifying the light-cone EoR 21-cm signal
• The Accretion flow in M87 is really MAD
• VLBI observations of bright AGN jets with KVN and VERA Array (KaVA): Evaluation of Imaging Capability
• Properties of the jet in M87 revealed by its helical structure imaged with the VLBA at 8 and 15 GHz
• MAGIC observations of the giant radio galaxy M87 in a low-emission state between 2005 and 2007
• Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm
• Keck Integral-Field Spectroscopy of M87 Reveals an Intrinsically Triaxial Galaxy and a Revised Black Hole Mass
• Detection of Superluminal Motion in the X-Ray Jet of M87
• agnpy: An open-source python package modelling the radiative processes of jetted active galactic nuclei
• Interferometric Monitoring of Gamma-ray Bright AGNs I: Results of Single-epoch Multifrequency Observations
• Supermassive black hole mass in the massive elliptical galaxy M87 from integral-field stellar dynamics using OASIS and MUSE with adaptive optics: assessing systematic uncertainties
• Spectral analysis of a parsec-scale jet in M87: Observational constraint on the magnetic field strengths in the jet
• The throughput calibration of the VERITAS telescopes
• Probing the central black hole in M87 with gamma-rays
• Implications from the velocity profile of the M87 jet: a possibility of a slowly rotating black hole magnetosphere
• The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale
• The response of black hole spark gaps to external changes: A production mechanism of rapid TeV flares?
• A Characterization of the ALMA Phasing System at 345 GHz
• Overview of the Observing System and Initial Scientific Accomplishments of the East Asian VLBI Network (EAVN)
• Curvature in the very-high energy gamma-ray spectrum of M87
• Relativistic Signatures of Flux Eruption Events Near Black Holes
• Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes
• Revisiting the black hole mass of M87* using VLT/MUSE Adaptive Optics Integral Field Unit data I: Ionized gas kinematics
• RAIKOU: A General Relativistic, Multi-wavelength Radiative Transfer Code
• Lepto-hadronic jet-disc model for the multi-wavelength SED of M87
• CLEAN imaging systematics of M87 radio jet
• Constraining the cosmic-ray pressure in the inner Virgo Cluster using H.E.S.S. observations of M 87
• The year-scale X-ray variations in the core of M87

Cited by in corpus (15)

• M87: a cosmic laboratory for deciphering black hole accretion and jet formation
• Co-precession of a curved jet and compact accretion disk in M87
• Reconnection-driven Flares in M87*: Proton-Synchrotron-powered GeV Emission
• Jet Archaeology and Forecasting: Image Variability and Magnetic Field Configuration
• Non-thermal Synchrotron Emission and Polarization Signatures during Black Hole Flux Eruptions
• Constraining eV-scale axion-like particle dark matter: insights from the M87 Galaxy
• Tracking X-ray Variability in Next Generation EHT LLAGN Targets
• Assessing the Role of Intrinsic Variability in Black Hole Parameter Inference using Multi-Epoch EHT Data
• Explaining the Origin of TeV Gamma Rays from M87 During High and Low States
• The infrared jet of M87 observed with JWST
• Constraints on High-Frequency Gravitational Waves from Graviton-Photon Conversion in the M87 Galaxy
• Spatially resolved spectral properties of M87* on event horizon scales
• ALMA publication statistics
• Driven Collisionless Reconnection of Force-free Flux Tubes: From Onset to Coalescence
• Nonuniform Particle Injection into Black Hole Jets by Radiative Magnetic Reconnection