Special Talk by Chris Nagele
Wednesday · 03:00 PM - 04:00 PM
Radiation transfer simulations of black hole spectra
Chris Nagele (Johns Hopkins University)
Spectra from accreting black holes are one of our most powerful tools for understanding these enigmatic objects. These spectra, however, are not well understood. For example, stellar mass black holes and supermassive black holes exhibit different spectral properties, with the stellar mass black holes changing between different spectral states (hard and soft states) while the supermassive black holes have more uniform spectral slopes. We run radiation transfer post-processing of general relativistic magnetohydrodynamical simulations of black hole accretion, in order to generate spectral predictions. We use two radiation transfer codes, Pandurata and PTransX, to solve for thermal balance and ionization balance in different parts of the simulation. Our spectra are remarkably similar to observed trends, with a clear hard/soft dependence on accretion rate at M = 10 Msun and uniformly flat spectra in the supermassive regime. We also compute high resolution spectra in order to simulate emission lines coming from the accretion disk near the black hole. Our spectra contain Fe Kalpha lines with equivalent widths (50-200 eV) and line shapes consistent with observations. We find, however, that the breadth of these lines is due to several factors, and not simply to extreme relativistic motions near the black hole, as is almost always assumed. We discuss how physical quantities from our simulations can be incorporated into models which perform black hole parameter inference, thereby breaking some of the degeneracy associated with these models.
Chris Nagele (Johns Hopkins University)
Spectra from accreting black holes are one of our most powerful tools for understanding these enigmatic objects. These spectra, however, are not well understood. For example, stellar mass black holes and supermassive black holes exhibit different spectral properties, with the stellar mass black holes changing between different spectral states (hard and soft states) while the supermassive black holes have more uniform spectral slopes. We run radiation transfer post-processing of general relativistic magnetohydrodynamical simulations of black hole accretion, in order to generate spectral predictions. We use two radiation transfer codes, Pandurata and PTransX, to solve for thermal balance and ionization balance in different parts of the simulation. Our spectra are remarkably similar to observed trends, with a clear hard/soft dependence on accretion rate at M = 10 Msun and uniformly flat spectra in the supermassive regime. We also compute high resolution spectra in order to simulate emission lines coming from the accretion disk near the black hole. Our spectra contain Fe Kalpha lines with equivalent widths (50-200 eV) and line shapes consistent with observations. We find, however, that the breadth of these lines is due to several factors, and not simply to extreme relativistic motions near the black hole, as is almost always assumed. We discuss how physical quantities from our simulations can be incorporated into models which perform black hole parameter inference, thereby breaking some of the degeneracy associated with these models.
SED Director’s Seminar
Thursday · 12:00 PM - 01:00 PM
Please join us for the SED Director’s Seminar hosted by the Exoplanets and Stellar Astrophysics Laboratory, Code 667!
Exploring New Worlds with HWO and BARBIE
Natasha Latouf (NPP postdoc)
Coronagraphoto: An Open-Source Image Simulation Tool for the Habitable Worlds Observatory
Corey Spohn (NPP postdoc)
Detectability of O₂ in Simulated Low-Resolution Reflected Spectra of Earth-like Planets
Simon Petrus (NPP postdoc)
Exploring New Worlds with HWO and BARBIE
Natasha Latouf (NPP postdoc)
Coronagraphoto: An Open-Source Image Simulation Tool for the Habitable Worlds Observatory
Corey Spohn (NPP postdoc)
Detectability of O₂ in Simulated Low-Resolution Reflected Spectra of Earth-like Planets
Simon Petrus (NPP postdoc)
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