[seminar] Astro Journal Club on 6 April

[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
about the recent spectroscopic discovery of the most distant and oldest
galaxy known in the universe - GNz11 at a redshift of z=11.1.

Presenter: Jacinta Delhaize
Paper title: A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble
Space Telescope Grism Spectroscopy
Authors: Oesch, P. A., Brammer, G., van Dokkum, P. G., et al.
Paper status: Published in the Astrophysical Journal, Volume 819, Issue 2
(2016)

Summary:
We present Hubble WFC3/IR slitless grism spectra of a remarkably bright z
>= 10 galaxy candidate, GN-z11, identified initially from CANDELS/GOODS-N
imaging data. A significant spectroscopic continuum break is detected at
lambda =1.47+/- 0.01 micron. The new grism data, combined with the
photometric data, rule out all plausible lower redshift solutions for this
source. The only viable solution is that this continuum break is the
Ly-alpha break redshifted to z(grism)=11.09-0.12+0.08, just 400 Myr after
the Big Bang. This observation extends the current spectroscopic frontier
by 150 Myr to well before the Planck (instantaneous) cosmic reionization
peak at z=8.8, demonstrating that galaxy build-up was well underway early
in the reionization epoch at z > 10. GN-z11 is remarkably, and
unexpectedly, luminous for a galaxy at such an early time: its UV
luminosity is 3x larger than L* measured at z = 6-8. The Spitzer IRAC
detections up to 4.5 micron of this galaxy are consistent with a stellar
mass of 1e9 Msun. This spectroscopic redshift measurement suggests that
James Webb Space Telescope (JWST) will be able to similarly and easily
confirm such sources at z > 10 and characterize their physical properties
through detailed spectroscopy. Furthermore, WFIRST, with its wide-field
near-IR imaging, would find large numbers of similar galaxies and
contribute greatly to JWST's spectroscopy, if it is launched early enough
to overlap with JWST.

Link to the paper: http://adsabs.harvard.edu/abs/2016ApJ...819..129O

Link to the press release:

http://www.space.com/32150-farthest-galaxy-smashes-cosmic-distance-record.html

Hope to see you all on Wednesday!

Cheers,
Oskari