Home
News
This Month
Introduction
Observing
Science
Gallery
Information
Site Map
|
|
The Subaru Seminar is
usually held in Room 104 of the Hilo Base Facility, adjacent
to the main lobby. Everyone is welcome to attend. If you are
interested in giving a seminar, please contact Subaru seminar organizers
(Tadayuki Kodama, Naoyuki Tamura, Tomonori Usuda)
by email : sseminar_at_subaru.naoj.org (please change"_at_" to @).
May 7, Monday, at 10:30 am
" The 11 Gyr Evolution of Star-forming galaxies: the HiZELS/H-alpha view at z=2.2, 1.5, 0.8 & 0.4 "
David Sobral
(Leiden University, Netherlands)
I will present new deep and wide narrow-band surveys undertaken with UKIRT,
Subaru and the VLT; a unique combined effort to select large, robust samples
of H-alpha (Ha) emitters at z=0.40, 0.84, 1.47 and 2.23 (corresponding to
look-back times of 4.2, 7.0, 9.2 and 10.6 Gyrs) in a uniform manner over ~2
sqdeg in the COSMOS and UDS fields. The deep multi-epoch Ha surveys are
sensitive to Milky-Way SFRs out to z=2.2 for the first time, while the wide
area and the coverage over two independent fields allows to greatly overcome
cosmic variance. A total of over ~600 sources per epoch are homogeneously
selected. Overall, the evolution seen in Ha is in good agreement with the
evolution seen using inhomogeneous compilations of other tracers of star
formation, such as FIR and UV, jointly pointing towards the bulk of the
evolution in the last 11 Gyrs being driven by a strong luminosity/SFR
increase from z~0 to z~2.2. Our uniform analysis allows to derive the
Ha star formation history of the Universe, for which a simple
time-parametrisation is a good approximation for the last 11Gyrs.
Both the shape and normalisation of the Ha star formation history are
consistent with the measurements of the stellar mass density growth,
confirming that our Ha analysis traces the bulk of the formation of stars
in the Universe up to z~2.2. We are also exploring the large, multi-epoch
and homogeneously selected samples of Ha emitters to conduct detailed
morphology, dust, clustering, environment and mass studies which are
providing us with a unique view on the evolution of star-forming galaxies
and what has been driving it for the past 11 Gyrs.
Seminars are also held at JAC,
CFHT,
and IfA.
|