[seminar] Astro Journal Club on 9 March

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm in the seminar
room F-201 of the Physics Department. This time we will discuss about the
galaxy cluster MACS J1931.8 and its starbursting central galaxy.

Presenter: Oskari Miettinen
Paper title: Starbursting brightest cluster galaxy: a Herschel view of the
massive cluster MACS J1931.8-2634
Authors: Santos, J. S., Balestra, I., Tozzi, P., et al.

Summary:
We investigate the dust-obscured star formation (SF) properties of the
massive, X-ray-selected galaxy cluster MACS J1931.8-2634 at z = 0.352.
Using far-infrared (FIR) imaging in the range 100-500 micron obtained with
the Herschel telescope, we extract 31 sources (2sigma) within r ~ 1 Mpc
from the brightest cluster galaxy (BCG). Among these sources, we identify
six cluster members for which we perform an analysis of their spectral
energy distributions (SEDs). We measure total infrared luminosity (LIR),
star formation rate (SFR) and dust temperature. The BCG, with LIR = 1.4 ×
1.0e12 Lsun is an ultraluminous infrared galaxy and hosts a type-II active
galactic nuclei (AGN). We decompose its FIR SED into AGN and starburst
components and find equal contributions from AGN and starburst. We also
recompute the SFR of the BCG finding SFR = 150 +/- 15 Msun/yr. We search
for an isobaric cooling flow in the cool core using Chandra X-ray data,
and find no evidence for gas colder than 1.8 keV in the inner 30 kpc, for
an upper limit to the instantaneous mass-deposition rate of 58 Msun/yr at
95 per cent c.l. This value is 3× lower than the SFR in the BCG,
suggesting that the on-going SF episode lasts longer than the intracluster
medium cooling events.

Link to the paper: http://adsabs.harvard.edu/abs/2016MNRAS.456L..99S

Hope to see you all on Wednesday!

Cheers,
Oskari