Galaxy messier 87
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Exploring the Galaxy Messier 87: Insights from Recent Research
Introduction to Messier 87 and Its Prominent Jet
Messier 87 (M87) is a nearby radio galaxy known for its prominent jet, which extends from sub-parsec (pc) to kiloparsec (kpc) scales. This galaxy is a prime candidate for studying jet formation due to its proximity and the large mass of its central black hole (BH)1. The jet in M87 is limb-brightened and expands parabolically from a resolved core, suggesting that the jet's sheath may be anchored in the inner portion of the accretion disk1.
High-Resolution Observations and Jet Structure
Using the Global mm-VLBI Array (GMVA) at 86 GHz, researchers have achieved an angular resolution of approximately 50 microarcseconds, corresponding to a spatial resolution of about 7 Schwarzschild radii (Rsch)1. These observations reveal a parabolically expanding jet emanating from a core of about 8-13 Rsch in size, with a brightness temperature indicating magnetic energy dominance at the jet base1.
Polarimetric Imaging and Accretion States
The Event Horizon Telescope (EHT) has provided groundbreaking images of the supermassive black hole at the core of M87, including the first linearly polarized images of the accretion flow2 4. These images show a spiraling polarization pattern, which supports the presence of magnetically arrested disks (MADs)4. The analysis of these polarimetric images helps discriminate between different accretion states and provides insights into the magnetic field geometry and black hole spin2 4.
Very-High-Energy Gamma-Ray Emission
M87 is also known for its very-high-energy (VHE) gamma-ray emissions. Observations have shown that these emissions originate in the immediate vicinity of the black hole, where particles are accelerated to extremely high energies5 7. This is supported by simultaneous radio and VHE gamma-ray observations, which reveal flaring activity and increased radio flux from the galaxy's nucleus5 7.
Black Hole Mass and Its Implications
M87 hosts one of the most massive known black holes, with a mass of approximately 6.3 billion solar masses6. This massive black hole plays a crucial role in the dynamics of the galaxy and the formation of its jet. The presence of such a massive black hole also provides a unique opportunity to test theories of gravity and the physics of black hole accretion6 10.
Photon Ring and Gravitational Lensing
The EHT's observations have also highlighted the importance of the photon ring, a highly lensed structure where photons make multiple half orbits around the black hole before reaching the observer4. This region is depolarized relative to more direct emission due to destructive interference of oppositely spiraling electric field vectors, which is a result of strong gravitational lensing4.
Conclusion
The galaxy Messier 87 continues to be a focal point for astrophysical research, providing valuable insights into jet formation, black hole accretion, and high-energy astrophysics. High-resolution imaging and polarimetric studies have significantly advanced our understanding of the physical conditions near the jet base and the role of magnetic fields in shaping the jet structure. Additionally, observations of VHE gamma-ray emissions and the massive black hole at the center of M87 offer critical tests for theoretical models of black hole physics and general relativity.
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Most relevant research papers on this topic
The limb-brightened jet of M87 down to the 7 Schwarzschild radii scale
The limb-brightened jet of M87 shows magnetic energy dominance at its base, with a diameter of 5 Rsch, suggesting it may be anchored in the inner portion of the accretion disk.
Highly CitedDiscriminating Accretion States via Rotational Symmetry in Simulated Polarimetric Images of M87
The proposed decomposition of linear polarization field into basis functions can effectively discriminate between accretion states in M87 simulated images, improving constraints on theoretical models.
Nuts and bolts of seeing a black hole
The Event Horizon Telescope has captured the first images of a supermassive black hole, revealing its dark shadow in the centre of galaxy Messier 87.
Photon Ring Symmetries in Simulated Linear Polarization Images of Messier 87*
Magnetically arrested disk simulations show relative depolarization of the photon ring due to destructive interference of oppositely spiraling electric field vectors, potentially producing up to 50% depolarization in the photon ring region.
Radio Imaging of the Very-High-Energy γ-Ray Emission Region in the Central Engine of a Radio Galaxy
The highest energy emission from active galaxies originates in the immediate vicinity of the black hole, with charged particles being accelerated to very high energies in close proximity.
Highly CitedTwo ten-billion-solar-mass black holes at the centres of giant elliptical galaxies
Two massive black holes with masses of 9.7 billion solar masses were discovered in giant elliptical galaxies NGC 3842 and NGC 4889, suggesting different evolutionary processes influence the growth of the largest galaxies and their black holes.
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