Transcript seminario di fisica - Scuola Normale Superiore

SEMINARIO DI COSMOLOGIA
Mercoledì 19 ottobre 2016
ore 15:00
Scuola Normale Superiore
Pisa
Aula Marie Curie
Guilaine Lagache
( Laboratoire d’Astrophysique de Marseille)
terrà un seminario dal titolo:
“Intensity mapping of the atomic carbon [CII] line in postreionization and reionization epoch with CONCERTO”
Abstract:
The fine structure line [CII] at 158 microns is one of the brightest emission lines in the spectra of
galaxies. It is considered to be the dominant coolant for neutral atomic gas in the interstellar medium.
Conveniently, [CII] is redshifted into the sub-millimeter and millimeter atmospheric windows for
4.5<z<9. At high redshift, [CII] is thus a unique tracer of galaxy formation and a promising probe of the
epoch of reionization (z>6). However, so far, [CII] studies of very distant galaxies have been limited,
with detection of only a handful of galaxies. The full power of ALMA will revolutionize the field, detecting
[CII] in individual galaxies in the heart of the reionization era. However, while ALMA will probably
follow-up hundreds of high-redshift galaxies, its small field of view and narrow bandwidth will strongly
limit
its
sensitivity/efficiency
to
conduct
large
unbiased
spectral
line
surveys.
Rather than detecting [CII] in selected galaxies, we propose to map in 3-D the intensity due to the [CII]
line emission, a technique known as Intensity Mapping. This technique measures signal fluctuations
produced by the combined emission of the galaxy population on large regions of the sky in a wide
frequency (thus redshift) band, and thus increases sensitivity to faint sources. I will discuss how [CII]
intensity mapping measurements can offer a straightforward alternative for tracing the large structure of
galaxies at z>4.5. By measuring [CII] fluctuations, I will show how we can obtain unprecedented
constraints on star formation and dust build-up at a key epoch in the Universe. I will also discuss how
cross-correlation of the signals (e.g. [CII] and galaxy surveys), as well as the lower redshift (z<2) COline fluctuations, could be used to further understand the physics of galaxy formation and reionization.
Finally I will present the CONCERTO experiment, a [CII] spectrometer capable of covering few square
degrees with a high sensivitity and proposed as a new intensity mapping experiment.
Piazza dei Cavalieri, 7
56126 Pisa-Italy
tel: +39 050 509111
fax: +39 050 563513
13/10/2016