The extreme luminosity states of Sagittarius A*

TL;DR

This paper analyzes multi-wavelength observations of Sagittarius A* during its extreme luminosity states, demonstrating that synchrotron and SSC mechanisms explain the emission across radio, NIR, and X-ray bands, with adiabatic expansion modeling the flare profiles.

Contribution

It provides a comprehensive interpretation of SgrA*'s luminosity states using SSC and synchrotron models, including detailed flare analysis with adiabatic expansion.

Findings

SSC emission explains NIR and X-ray flares.

Synchrotron emission accounts for low luminosity states.

Adiabatic expansion models the flare profiles and peak luminosities.

Abstract

We discuss mm-wavelength radio, 2.2-11.8um NIR and 2-10 keV X-ray light curves of the super massive black hole (SMBH) counterpart of Sagittarius A* (SgrA*) near its lowest and highest observed luminosity states. The luminosity during the low state can be interpreted as synchrotron emission from a continuous or even spotted accretion disk. For the high luminosity state SSC emission from THz peaked source components can fully account for the flux density variations observed in the NIR and X-ray domain. We conclude that at near-infrared wavelengths the SSC mechanism is responsible for all emission from the lowest to the brightest flare from SgrA*. For the bright flare event of 4 April 2007 that was covered from the radio to the X-ray domain, the SSC model combined with adiabatic expansion can explain the related peak luminosities and different widths of the flare profiles obtained in the NIR and X-ray regime as well as the non detection in the radio domain.