From the first over-densitities to proto-clusters and clusters: The role of the environment

In force date
Call year
2017
Investigator
Helmut
Dannerbauer
Amount granted to the IAC Consortium
141.570,00 €
Description
Our overall aim is understandig to role of the environment from the first sources to the clusters appearing at the epoch of peak star formation. That is, a multi-wavelength study of the early Universe. This implies the understanding of the galaxies that re-ionised the Universe, as well as the processes that resulted in the formation of galaxies both in the field and in clusters and proto-clusters. In particular, we will study 1) the conversion of molecular gas in stars, and 2) how this process occurs depending on whether the star forming galaxies are isolated or in clusters. The study will encompass both the ultraviolet-optical regime as well as the far IR-submillimetre and radio regime. We will study the feasibility of detecting the first galaxies with a micro-satellite, and study the first proto-clusters and clusters. More in detail, the following points summarise what we intend with this proposal:
1) The first objective is the understanding of the star formation process in elliptical galaxies. This is achieved by probing the cold molecular gas, the fuel of star formation, and dust, the by-product of this formation process, in distant clusters. These will be done in high-z proto- clusters, and recently formed clusters, with far IR and radio data. Through radio interferometry we will search for large reservoirs of molecular gas in a well selected sample of galaxies in clusters.
2) Another important aspect is probing the environmental-dependent evolution of the most massive galaxies. We will compare the properties of cluster and available field galaxies. The combination of a proven but novel technique, proper target selection and an excellent dataset promises a breakthrough in understanding the formation process of the progenitors of elliptical galaxies which dominate local galaxy clusters.
3) We will carry out a study of the highest redshift over-densities. We have already detected two high-z proto-clusters at z~5.2 and z~6.5. The one at z~ 5.2 has sources detected both in the UV-optical and in the sub millimetre-radio ranges. This offers the possibility of following up the star formation process both in the UV-optical and in the radio.
4) Often the high-z sources are only known for their UV rest-frame emission. Little is known however of their radio emission. We propose, in collaboration with our colleagues from the CRYA, a radio astronomy institute in Morelia (Mexico), to produce a user-friendly catalogue of the VLA archive. We will then have data in the radio for our sources. Data that will help us to determine star formation rates, the escape fraction, and the density of ionising photons, free from extinction.
5) Our long range plan is to set up a strategy for detecting the first galaxies, those responsible for re-ionising the Universe. According to our models, this requires observations of a large field of view with a near IR camera. Our team has attempted to use ground based telescopes, such as the GTC with OSIRIS and CIRCE. In fact we have had more than 50 hours of GTC time to observe LAEs at z~6.5 and z~9, admittedly with limited success. We realise, however, that the best way to perform that detection is with a near IR camera on board of a micro-satellite. We propose here to carry out preliminary studies of both the camera and the micro-satellite.