Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
The Black Hole Mass, Stellar M/L, and Dark Halo in M87
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular cluster velocities out to 8 effective radii. We simultaneously fit for four parameters, black hole mass, dark halo core radius, dark halo circular velocity, and stellar mass-to-light ratio. We find a black hole mass of 6.4(+-0.5)x10^9 Msun(the uncertainty is 68% confidence marginalized over the other parameters). The stellar M/L_V=6.3+-0.8. The best-fitted dark halo core radius is 14+-2 kpc, assuming a cored logarithmic potential. The best-fitted dark halo circular velocity is 715+-15 km/s. Our black hole mass is over a factor of 2 larger than previous stellar dynamical measures, and our derived stellar M/L ratio is 2 times lower than previous dynamical measures. When we do not include a dark halo, we measure a black hole mass and stellar M/L ratio that is consistent with previous measures, implying that the major difference is in the model assumptions. The stellar M/L ratio from our models is very similar to that derived from stellar population models of M87. The reason for the difference in the black hole mass is because we allow the M/L ratio to change with radius. The dark halo is degenerate with the stellar M/L ratio, which is subsequently degenerate with the black hole mass. We argue that dynamical models of galaxies that do not include the contribution from a dark halo may produce a biased result for the black hole mass. This bias is especially large for a galaxy with a shallow light profile such as M87, and may not be as severe in galaxies with steeper light profiles unless they have a large stellar population change with radius.
verdicts
UNVERDICTED 3representative citing papers
No photon-ALP conversion signal found in HAWC data from M87, producing competitive constraints excluding ALP masses of 10^{-8} to 10^{-6} eV for couplings above 5×10^{-12} GeV^{-1}.
Negative tidal charge enlarges the shadow of rotating braneworld black holes while inhomogeneous plasma shrinks it and homogeneous plasma enlarges it; EHT data limits q to roughly -1.15 to 0.45 for M87* in the low-density limit.
citing papers explorer
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Dimming of Photon Ring due to Photon-Axion Conversion around Kerr Black Holes
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
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Constraints on axion-like particles from ultra-high-energy observations of M87 with the HAWC observatory
No photon-ALP conversion signal found in HAWC data from M87, producing competitive constraints excluding ALP masses of 10^{-8} to 10^{-6} eV for couplings above 5×10^{-12} GeV^{-1}.
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Investigating the interplay of the braneworld gravity and the plasma environment on the black hole shadow
Negative tidal charge enlarges the shadow of rotating braneworld black holes while inhomogeneous plasma shrinks it and homogeneous plasma enlarges it; EHT data limits q to roughly -1.15 to 0.45 for M87* in the low-density limit.