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Astrophysics

Research in Astrophysics includes the computational modeling of flows from QSOs (Quasars). QSOs are extremely luminous objects and thus are the objects that we can see farthest away. They are found at the center of galaxies, have a size comparable to our Solar System, and emit more light than their host galaxies. This large amount of emission from a relatively small region can be accounted for by mass accreting (falling towards) onto a supermassive black hole (a black hole of millions to billions of solar masses).

Observational and theoretical evidence supports the idea that the accreting mass forms an accretion disk, and that the UV/optical emission of the QSO could be coming directly from the surface of the accretion disk itself. Additionally, in about 10% of QSOs, high-velocity outflows (in the order of thousands of kilometers per second) are detected through the presence of Broad Absorption Lines in their spectra.

We are exploring, through the development of computational models, the scenario in which these QSO outflows are coming directly from the accretion disk.

astro-physics

Observational Evidence for Accretion Disk in QSOs

Note the good agreement of observational data (blue) with theoretical accretion disk calculations (green).

Blue: QSO average spectrum.

Green: Theoretical accretion disk spectra for different characteristic temperatures

astro-physics

Observational Evidence for Accretion Disk in QSOs

Note the good agreement of observational data (gray) with theoretical accretion disk calculations (black-line).

Gray: QSO average residual spectrum; that is the difference spectra as the QSO varies in luminosity.

Black line: Best fit accretion disk residual spectrum.

Black dotted line: Best fit blackbody spectrum.

astro-physics

Simple Schematic Representation of the Accretion Disk Wind Scenario for QSOs

Note that X-ray emission, within this scenario, is being emitted within the inner radius of the accretion disk closer to the black hole.

astro-physics

QSO disk wind computational results: velocity field vectors superimposed with density contours.

astro-physics     astro-physics

CIV 1549 Spectral Line Profiles Calculated from Computational Models

(Assuming Single Scattering)