Found 4 talks width keyword luminosity function

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Tuesday March 19, 2013
Dr. Nicolas Laporte
IAC

Abstract

Evolution of galaxies is relatively well known up to z ~ 5, but beyond this limit and regarding the few number of galaxies confirmed by spectroscopy, their evolution is still uncertain. In the last five years, many projects and instruments aiming at pushing the limits of the Universe have emerged. Among them, the WIRCam Ultra Deep Survey (WUDS), a very large (~400 arcmin^2 field of view) and deep (m_H=27.00 AB) survey covering wavelength from Y to Ks bands, dedicated to select the brightest sources at z > 4.5, has just been finished.This survey takes benefit from the deep images from the CFHT-LS (Groth Strip) in u, g, r, i and z-band to improve the wavelength coverage and thus the determination of photometric redshift in each sample. The evolution of galaxies has been studied through the evolution of the UV Luminosity Function from z~5 up to z~9. During this talk I will present you the WIRCam Ultra Deep Survey and the most popular method used to select the very high-redshift sources. Then I will focus on the determination of the luminosity function and on the implications of this evolution on the Epoch of Reionization. I will finish this presentation by giving some perspectives, and especially the results that we can expected from futures instruments and telescopes (e.g. EMIR @ GTC, KMOS and MUSE @ VLT, JWST, E-ELT).


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Friday February 24, 2012
Dr. David Sobral
Leiden University, the Netherlands

Abstract

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.


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Thursday March 11, 2010
Dr. Almudena Prieto
Instituto de Astrofísica de Canarias, Spain

Abstract

Spectral energy distributions (SEDs) of the central few tens of parsec region of some of the nearest active galactic nuclei (AGN) are presented. Peering into the nucleus at these scales, it is found that the intrinsic shape of the spectral energy distribution of an AGN and inferred bolometric luminosity largely depart from those currently on use, mostly extracted from low resolution data. The shape of the SED is different and the AGN luminosities can be overestimated by up to two orders of magnitude if relying on IR satellite data.
Although the shape of these SEDs are currently limited by the availability of high angular resolution data beyond ~20 μ, a prediction from this work is that a major contribution from cold dust below 100 K to these cores is not expected. Over the nine orders of magnitude in frequency covered by these SEDs, the power stored in the IR bump is by far the most energetic fraction of the total energy budget in these cores, accounting for more than 70% of the total.

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Wednesday October 29, 2008
Dr. Hans Zinnecker
Astrophysical Institute Potsdam, Germany

Abstract

In the first (optical) part, we present our recent results on mass and luminosity function of Galactic open clusters, a new statistical study based on the ASCC-2.5 catalogue of bright stars, complete to about 1 kpc around the Sun. This includes a new determination of the fraction of field stars born in open clusters. It also briefly addresses the issue whether all massive stars are exclusively born in clusters. In the second (infrared) part, we discuss the prospects of a 42m European ELT to "see" the origin of massive stars in dense embedded protoclusters, by penetrating dense proto- cluster clouds up to 200 mag of visual extinction at 2-5 microns. High-angular resolution AO imaging as well as 3D integral field spectroscopy are required to study the stellar density, binary content, and dynamical properties of these highly obscured, massive, compact star clusters.

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