[seminar] Astro Journal Club on 21 January

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held again on Wednesday at 10:15 in the
seminar room F-201 of the Physics Department. This time we will discuss
about the recent simulations of black hole growth and AGN feedback.

Presenter: Ana - Marija Kozuljevic
Paper title: Black hole growth and AGN feedback under clumpy accretion
Authors: DeGraf, C., Dekel, A., Gabor, J., and Bournaud, F.

Abstract:
High-resolution simulations of supermassive black holes in isolated
galaxies have suggested the importance of short (10 Myr) episodes of
rapid accretion caused by interactions between the black hole and massive
dense clouds within the host. Accretion of such clouds could potentially
provide the dominant source for black hole growth in high-z galaxies, but
it remains unresolved in cosmological simulations. Using a stochastic
subgrid model calibrated by high-resolution isolated galaxy simulations,
we investigate the impact that variability in black hole accretion rates
has on black hole growth and the evolution of the host galaxy. We 
find
this clumpy accretion to more efficiently fuel high-redshift black hole
growth. This increased mass allows for more rapid accretion even in the
absence of high-density clumps, compounding the e
ffect and resulting in
substantially faster overall black hole growth. This increased growth
allows the black hole to eciently evacuate gas from the central region of
the galaxy, driving strong winds up to 2500 km/s, producing out outflows
10x stronger than the smooth accretion case, suppressing the inflow of
gas onto the host galaxy, and suppressing the star formation within the
galaxy by as much as a factor of two. This suggests that the proper
incorporation of variability is a key factor in the co-evolution
between black holes and their hosts.

Link to the paper: http://adsabs.harvard.edu/abs/2014arXiv1412.3819D

Hope to see you all on Wednesday!

Best regards,
Oskari Miettinen