***** EXAMPLE *****
Question and Discussion in Lecture XX (JanXX, 20XX)
In the lecture,
Write your questions (at least 1 in each lecture) on google doc with your name & student ID#In the discussion section (last ~30 min)
- Making a group consisting of 2(3) students.
- Choosing an interesting question in the google doc discussing results in the group(~20min)- Sharing the discussion results (~10 min)Write your questions and discussions below#Questions are in blue, while discussions are in black.
●(Kakuma, 122): How can we regulate the radiative efficiency for SMBH? With
simulation or is there any observational support?
○ (Qiu, 384; Kushibiki 125): The radiative efficiency is not a determined number.
It changes with the mass and the rotation speed of the BHs. There are lots ofdata support the results. So It is more likely depended on the observation.
(https://www.researchgate.net/publication/274895502_Radiative_efficiency_of_black_holes_in_AGN) In this paper, they have calculated a lot of BHs in
AGN and got different results. The efficiency is larger with larger mass androtation.
○ Radiative efficiency can be constrained in observation (Davis+2010,https://arxiv.org/pdf/1012.3213.pdf )

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(Kushibiki, 125): If Radiative efficiency is 10%, what is the rest of gravitational energy
released by accretion used for?
(Jian, 168): How to define bulge from disk and halo?
(Lu, 383; Abe, 610): The bulge is a round structure made primarily of oldstars, gas and dust. The halo primarily contains individual old stars andclusters of old stars. The outer parts of bulge is difficult to distinguish from thehalo. As we can see from the following figure.

The disk is a flattened region that surrounds the bulge in a spiral galaxy.It
contains mostly young stars, gas and dust, which are concentrated in spiralarms.
(Abe, 610): If the accretion is not isotropic, can the total rate of accretion become
bigger than the Eddington accretion rate?
(Qiu, 384): Will GRB occur when the black holes merge? If not, why is the merger ofneutron stars so special?
○ (Jian, 168; Lin 169): Probably no. GRBs are usually thought to be produced inultra-relativistic jet (inverse-Compton scattering of photons by energeticelectrons), while no jet is expected in a BBH merger. However, GRB canoccur before or after BBH merger, e.g. from death of a massive companion
star (arXiv:1310.4869) or from accretion disk (arXiv:1602.05140).
(Liang, 955): Why the GRB rate model is shifted compared to the GRB observed
data? Different parameters are assumed?
(Liang, 955): The blue/red-shifted velocity could be either due to outflow/inflow in thenear side or the inflow/outflow in the far side, so how to distinguish them?
○ (Kakuma,122; Liang, Soken-0955): We think we can’t see the inflow/outflow in
the far side of the galaxies because they may be absorbed by the galaxy itself
or we can’t see them because galaxy (star) is much brighter.
(Lin, 187): Can we estimate accretion rate directly from observations without theknowledge of radiative efficiency?
(Tang, 385): How could it be the possible mechanism for the direct collapse ofSMBHs? (Compared to the Fe core collapse of the main sequence stars?)(Ando, 117): How can we explain the super-Eddington accretion of the SMBH? Is
there any widely accepted explanation?
○ (Ando, 117; Tang, 385): Super-Eddington accretion of the SMBH is found tobe able to happen in some cases. When we say that the accretion rate islower than Eddington rate, it is to ensure that the matter can be confinedaround the black hole, but on the other hand, matter can be emitted by theSMBH in the form of jet, in this paper, they have done a simulation on theenergy density and magnetic field of SMBHs under super-Eddington

●accretion(https://arxiv.org/pdf/1709.02845.pdf)(Lu, 383):Why does the perpendicular trace indicate scattering by a central LyA
source?