科学研究
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2024.11.21
A new picture of active galactic nuclei disks [EN]
The current model of accretion disks, that of Shakura and Sunyaev (1973) asserts that such disks are geometrically thin, and are prone to a number of instabilities. One such instability is that of fragmentation due to self-gravity at radii larger than a few hundred black hole gravitational radii, which would limit the mass accretion rate to be well below that observed to occur. Recent GIZMO (La...
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2024.11.21
On the Formation, Evolution and the Environment of Low Surface Brightness Galaxies [EN]
The variations in the size of galaxies, and consequently, the formation of Low Surface Brighntess Galaxies (LSBGs) could be followed from one of two different effects: variations in the spin parameter of the halo (λ) or variations in the density of dark matter halos (McGaugh 2021). We test both scenarios by employing a simulated sample of galaxies drawn from the TNG100 run of the IllustrisTNG ...
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2024.11.20
Estimating and Studying Dust Attenuation From Galactic Spectra [EN]
In the past few years, we develop a method to estimate the dust attenuation curve of galaxies from full optical spectral fitting. One important advantage of this method is that the estimated dust attenuation curve is independent of the shape of theoretical dust attenuation curves. Based on the method, we investigate the dust attenuation in both stellar populations and ionized gas in kpc-scale r...
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2024.11.20
[PDS seminar] The instability mechanism of compact multiplanet systems [EN]
Numerical integrations of Kepler-like tightly packed planetary systems show that they are chaotic, with fairly short Lyapunov times, but that they can be stable against planet-planet or planet-star collisions for billions of years. Recent work by Petit et al. showed that this behavior was due to the overlap of three-body mean motion resonances. Caleb Lammers, Sam Hadden and I recently showed th...
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2024.11.15
Halo Responses to Baryonic Mechanisms at Small Scale [EN]
The Voids-within-Voids-within-Voids (VVV) project developed a series of extremely high-resolution N-body simulations to study haloes over the entire range of ΛCDM halo masses, from Earth mass to the largest clusters. In this talk, I will present our latest results about how baryons could modify these results for haloes with masses between 10^4 and 10^7 M_sun, below the threshold for galaxy for...
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