CALIFA

Calar Alto Legacy Integral Field Area Survey

This 3D integral field unit (IFU) survey (see also Sanchez et al. 2012) accumulates optical spectra spatially resolved over the full extent of 600 nearby galaxies, encompassing all Hubble types and sampling the full optical color magnitude diagram, in the local universe (0.005 < z < 0.03). The large field of view of the IFU covers the full optical extent of the selected galaxies down to a 3σ depth of 23 mag/arcsec-2. Compared to previous surveys, the CALIFA survey reaches larger galacto-centric radii, covers a longer wavelength range, and includes besides early-type also late-type galaxies. Studies in CALIFA include (a) stellar populations: ages, metallicities and abundance ratios; (b) ionized gas: distribution, excitation mechanisms and chemical abundances; and (c) kinematics: both from stellar and ionized gas components. Up to now, we have IFU data obtained and reduced for almost 300 galaxies, – half of the final sample.

Our group is mainly involved in three activies within the CALIFA collaboration: 1) kinematical studies of stellar and gas components – based on the superb IFU dataset, 2) characterization of the molecular gas properties of CALIFA galaxies and 3) investigations of the diffuse gas component of early type galaxies.

Within the working group “kinematics”, we lead the project “Dynamical Mass Distribution from Stellar and Gas Kinematics”. Our master student Markus Arzt, under the supervision of Prof. Bodo Ziegler, will focus on the comparison of the mass distribution inferred from stellar and gas kinematics in order to verify the dynamical models. Furthermore, this study will place constraints on the non-gravitational contribution to the ionized gas dispersion revealing the importance of turbulence.

The CALIFA galaxies have a large multi-wavelength coverage from the UV to the infrared including legacy surveys as GALEX, UKIDSS, WISE. However, a key piece for the complete understanding and interpretation of the nature and properties of the star formation in our investigated sample is missing: the cold molecular gas reservoirs, the fuel of star formation. We aim to provide the missing piece by obtaining interferometric CO maps with ALMA and PdBI matching the spatial resolution of the optical IFU data of 2″ (corresponding to a physical scale of 200 – 760 pc). Having the same spatial resolution both in the millimeter and optical window and covering the entire galaxy in CO and optical lines for a large number of targets, will be a unique feature of our survey in comparison to previous ones. The spatial resolved CO observations will enable us to reach the following science goals: i) Where did the gas come from?, ii) What are the conditions to turn gas into stars?, and iii) On which time-scales are stars being formed?.

The preparational work needed for the definition of the interferometric CO subsample is the subject of the ongoing master thesis by Johannes Puschnig , supervised by Dr. Helmut Dannerbauer and Prof. Bodo Ziegler.

learn more: Official CALIFA website