[seminar] Astro Journal Club on 1 April

[Oskari Miettinen]

Dear all,

The Astro Journal Club will be held tomorrow at 10:15 in the seminar room
F-201 of the Physics Department. This time we will discuss about the
(almost) dark HI system HI1232+20.

Presenter: Jacinta Delhaize
Paper title: (Almost) Dark HI Sources in the ALFALFA Survey: The
Intriguing Case of HI1232+20
Authors: Janowiecki, S., Leisman, L., Jozsa, G., et al.

Summary:
This paper is about an in-depth study of three galaxies that are detected
in 21cm radio maps of neutral hydrogen (HI), but not in the optical. The
authors conduct very sensitive optical imaging at the positions of these
'dark' galaxies to try and see if there are any very optically faint
galaxies that were not spotted in SDSS. They find that one of the dark
galaxies has a very low surface brightness (LSB) optical counterpart, but
the other two do not. The LSB has the highest HI-mass to light ratio ever
recorded. They discuss how such 'dark' galaxies fit into the picture of
galaxy evolution, and how this population might have been systematically
missed in all previous surveys.

Link to the paper: http://adsabs.harvard.edu/abs/2015ApJ...801...96J

See you all tomorrow!

Best wishes,
Oskari