The possible submillimeter bump and accretion-jet in the central supermassive black hole of NGC 4993

Abstract

NGC 4993, as a host galaxy of the electromagnetic counterpart of the first gravitational-wave detection of a binary neutron-star merger, was observed by many powerful telescopes from radio to $\gamma$-ray waveband. The weak nuclear activities of NGC 4993 suggest that it is a low-luminosity active galactic nuclear (LLAGN). We build the multi-waveband spectral energy distributions (SEDs) of NGC 4993 from literatures. We find that the radio spectrum at $\sim 100-300$ GHz is much steeper than that of low-frequency waveband (e.g., 6-100 GHz), where this break was also found in the supermassive black holes in our galaxy center (Sgr A*), and in some other nearby AGNs. The radio emission above and below this break may has different physical origins, which provide an opportunity to probe the accretion and jet properties. We model the multi-waveband SEDs of NGC 4993 with an advection-dominated accretion flow (ADAF)-jet model. We find that the high-frequency steep radio emission at millimeter waveband is consistent with the prediction of the ADAF, while the low-frequency flat radio spectrum is better fitted by the jet. Further more, the X-ray emission can be also explained by the ADAF model simultaneously. From the model fits, we estimate important parameters of the central engine (e.g., accretion rate near the horizon of the black hole and mass-loss rate in jet) for NGC 4993. This result strengthen that the millimiter, submillimer and deep X-ray observations are crucial to understand the weak or quiescent activities in supermassive black-hole systems. Further simultaneous millimeter and X-ray monitoring of this kind of LLAGNs will help us to better understand the physical origin of multiwaveband emission.

5 pages, 1 figure, ApJ in press

References in corpus (16)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-Time Emission from the Kilonova Ejecta
• A Deep Chandra X-ray Study of Neutron Star Coalescence GW170817
• The environment of the binary neutron star merger GW170817
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale
• The hard X-ray spectral evolution in X-ray binaries and its application to constrain the black hole mass of ultraluminous X-ray sources
• Supermassive black holes with high accretion rates in active galactic nuclei: II. the most luminous standard candles in the Universe
• Revisiting the "Fundamental Plane" of Black Hole Activity at Extremely Low Luminosities
• Results from an extensive simultaneous broadband campaign on the underluminous active nucleus M81*: further evidence for mass-scaling accretion in black holes
• On the origin of X-ray emission in some FR Is: ADAF or jet?
• ALMA and GMRT constraints on the off-axis gamma-ray burst 170817A from the binary neutron star merger GW170817
• Constraint on the black-hole spin of M87 from the accretion-jet model
• On the radio dichotomy of active galactic nuclei
• An accretion-jet model for M87: interpreting the spectral energy distribution and Faraday rotation measure
• Exploring the accretion model of M87 and 3C 84 with the Faraday rotation measure observations
• Hard X-ray Emission from the M87 AGN Detected with NuSTAR

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