[seminar] Astro Journal Club on 25 May

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm (sharp) in the
seminar room F-201 of the Physics Department. This time we will discuss a
recent Nature paper on the supermassive black hole in the elliptical
galaxy NGC 1600.

Presenter: Ivan Delvecchio
Paper title: A 17-billion-solar-mass black hole in a group galaxy with a
diffuse core
Authors: Thomas, J., Ma, C.-P., McConnell, N. J., et al.
Paper status: Published in Nature (2016, Vol. 532, 340)

Summary:
Quasars are associated with and powered by the accretion of material onto
massive black holes; the detection of highly luminous quasars with
redshifts greater than z=6 suggests that black holes of up to ten billion
solar masses already existed 13 billion years ago. Two possible
present-day 'dormant' descendants of this population of 'active' black
holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres
of the Leo and Coma galaxy clusters, which together form the central
region of the Great Wall-the largest local structure of galaxies. The most
luminous quasars, however, are not confined to such high-density regions
of the early Universe; yet dormant black holes of this high mass have not
yet been found outside of modern-day rich clusters. Here we report
observations of the stellar velocity distribution in the galaxy NGC 1600 -
a relatively isolated elliptical galaxy near the centre of a galaxy group
at a distance of 64 megaparsecs from Earth. We use orbit superposition
models to determine that the black hole at the centre of NGC 1600 has a
mass of 17 billion solar masses. The spatial distribution of stars near
the centre of NGC 1600 is rather diffuse. We find that the region of
depleted stellar density in the cores of massive elliptical galaxies
extends over the same radius as the gravitational sphere of influence of
the central black holes, and interpret this as the dynamical imprint of
the black holes.

Link to the paper: http://adsabs.harvard.edu/abs/2016Natur.532..340T

See you all on Wednesday!

Cheers,
Oskari