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High resolution spectral and spatial characterization of Sgr A* accretion flow dynamics with Chandra-HETG

Presentation #104.06 in the session ISM/Galaxies - Poster Session.

Published onMay 03, 2024
High resolution spectral and spatial characterization of Sgr A* accretion flow dynamics with Chandra-HETG

Within 5′′-10′′ of central Supermassive Black Hole (SMBH) Sgr A*, we find pulsar wind nebula PWN G359.95-0.04, massive star cluster IRS 13E, and hundreds of X-ray point and extended sources, making it a challenge to investigate the low-luminosity accretion flow of Sgr A* with traditional X-ray background subtraction techniques. We analyze the 10-5 Ledd accretion flow by jointly fitting source and background quiescent emission obtained from ~ 1 Ms Chandra HETG-S (High Energy Transmission Gratings Spectrometer; Canizares et al. 2005) data, extracted in Corrales et al. 2020. We test two models to fully interpret the high resolution spectrum: a Radiatively Inefficient Accretion Flow (RIAF) model and simulations of colliding stellar winds arising from the 20-30 Wolf-Rayet stars in the region based on work in Russell et al. 2017. We find that the data is unable to differentiate between the two models with high significance, but our best-fit RIAF model is consistent with an inflow balanced by an outflow. In addition, we find a subsolar Iron abundance, consistent with results from a nearby transient (Ponti et al. 2016), but low compared to the ~2 Zsolar metallicity found in nearby GC stars (Do et al. 2018). We also provide preliminary results on our efforts to disentangle nearby contaminating X-ray sources by applying novel machine learning techniques to map out nearby X-ray emission from different spectral sources.

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