SFDM4SUBMM · Star formation in the central regions of active galaxies and data mining in radioastronomy at sub-millimetre wavelengths

Final Activity and Management Report Summary - SFDM4SUBMM (Star formation in the central regions of active galaxies and data mining in radioastronomy at submillimeter wavelengths)

The fellow has worked on the study of the structure and dynamics of galaxies, as well as the role of the environment on galaxy evolution, emphasising the interstellar medium and in particular its neutral phase, both atomic and molecular. He has also studied the possible mechanisms responsible for episodes of starburst and nuclear activity in the central regions of galaxies, such as inflow of material towards the nuclear regions due to bars, spiral arms, merger events, etc. All his work is being done mainly with the help of interferometers (such as SMA, PdB at mm/submm and VLA at cm) and single-dish radiotelescopes (Effelsberg and IRAM 30m among others). The main results of this project are the following: Radio galaxies: Molecular gas in the closest radio galaxy, Centaurus A (NGC 5218). This source is one of the best studied extragalactic objects in the sky, and we worked on mapping the molecular gas as traced by CO along its minor axis dust lane. Also, we observed atomic gas along the line of sight, which seems to prove the conversion between molecular gas and atomic gas due to AGN processes close to the active nucleus. The SMA CO(2-1) BODEGA (Below 0 DEgree GAlaxies) Legacy Project, http://bodega.iaa.es. In this legacy program we aim to build and analyse in a systematic way the largest high-resolution CO survey of nearby galaxies to date. This will allow to classify the main properties of the molecular gas in CO-bright galaxies, including its morphology, kinematics and physical conditions. This Legacy Project combines members of CfA and ASIAA, with a long experience with SMA, as well as members of other institutes (IAA-CSIC, ATNF-CSIRO, Univ. of Granada) that are in charge of processing and analysing data at other wavelengths to trace the different components of the ISM and assess nuclear activity. We found that a total of 86% of the galaxies possess a CO(2-1) distribution that peaks at their nuclei, with characteristic sizes of the central components smaller than 1 kpc, and 500 pc for at least 50% galaxies of the sample. When compared to other samples of normal galaxies, we found a higher rate of galaxies with concentrated molecular gas within the inner 500 pc, 86% in our sample vs 45% in BIMA-SONG. It is likely for more IR luminous systems to systematically exhibit larger gas concentrations. The difference is difficult to explain just from higher excitation conditions in the centre due to SB/AGN. This effect might be related to possible interaction events that facilitate the formation of bars which drive gas to the centre. AMIGA project: The AMIGA project (Analysing the interstellar Medium of Isolated Galaxies) is an exhaustive study of a complete sample of ~1000 isolated galaxies and associated database. The fellow worked on the characterisation of the atomic and molecular gas of this sample of isolated galaxies, under the supervision of L. Verdes-Montenegro (PI of the project). The timeline of the Marie Curie project is synchronised with the project Atacama Large Millimeter Array (ALMA), whose ALMA's early science starts in September 2011. Our aim is to make a follow-up of these sources with ALMA, which will provide further individual analysis and modelling. The evaluation of different calibration techniques at SMA have been a priority during this work, as might be applied in ALMA.

Data: CORDIS, © European Union