[seminar] Astro Journal Club on 1 July

[Oskari Miettinen]

Dear all,

The Astro Journal Club will be held on Wednesday at 10:15 in the seminar
room F-201 of the Physics Department. This time we will discuss about the
star formation rate distributions of X-ray AGN host galaxies and normal
main-sequence galaxies.

Presenter: Ivan Delvecchio
Paper title: ALMA and Herschel reveal that AGN and main-sequence galaxies
have different star formation rate distributions
Authors: Mullaney, J. R., Alexander, D. M., Aird, J., et al.

Summary:
Using deep Herschel and ALMA observations, we investigate the star
formation rate (SFR) distributions of X-ray AGN host galaxies at 0.5<z<1.5
and 1.5<z<4, comparing them to that of normal, star-forming (i.e.,
"main-sequence", or MS) galaxies. We find 34-55 per cent of AGNs have SFRs
at least a factor of two below that of the average MS galaxy, compared to
~15 per cent of all MS galaxies, suggesting significantly different SFR
distributions. Indeed, when both are modelled as log-normal distributions,
the mass and redshift-normalised SFR distributions of AGNs are roughly
twice as broad, and peak ~0.4 dex lower, than that of MS galaxies.
However, like MS galaxies, the normalised SFR distribution of AGNs appears
not to evolve with redshift. Despite AGNs and MS galaxies having different
SFR distributions, the linear-mean SFR of AGNs derived from our
distributions is remarkably consistent with that of MS galaxies, and thus
with previous results derived from stacked Herschel data. This apparent
contradiction is due to the linear-mean SFR being biased by bright
outliers, and thus does not necessarily represent a true characterisation
of the typical SFR of AGNs.

Link to the paper: http://adsabs.harvard.edu/abs/2015arXiv150605459M

Hope to see you all on Wednesday!

Cheers,
Oskari