Competitive Science with the WHT for Nearby Unresolved Galaxies Reynier Peletier Kapteyn Astronomical Institute Groningen

Imaging surveys give extended 2-dimensional coverage of galaxies up to z~1 BUT: Spectroscopic followup generally only targets the center (e.g. SDSS) Example: most stellar population studies of unresolved galaxies only publish results on the central stellar populations (e.g. Trager et al., Gonzalez 1993, Kuntschner 2000, R. Smith et al. 2009, etc.).

The stellar populations in the centers of galaxies are not representative for the whole galaxy! Needed: an instrument that can survey whole galaxies.

Observing Modes 1. Obtaining 2-dimensional information using a large IFU 2. Using 20 mini-IFU's with diameters of about 10'', sampling of about 1'' 3. Using many single fibers and a large FOV

Example: The SAURON project. Measuring morphology, stellar and gas Kinematics, stellar populations and ionized gas properties at the same time. Observing mode 1: Using 1 large IFU

Total flux (narrow band)‏ Morphology, photometry Absorption lines Stellar kinematics LOSVD (V, ,h3,h4)‏ Line indices H , Mgb, Fe5015, Fe5270 Emission lines Gas distribution H , [OIII], [NI] Gas kinematics A SAURON spectrum HH [OIII] SAURON Observations: A Resolution ~1200 Field Size: 30''x40'', sampling 0.95''

Accomplishments of SAURON: - Determine v and σ maps in the inner regions (inside r e ) of 48 ellipticals/S0's. - Stellar M/L in inner regions: almost no dark matter - Ionized gas in 75% of these E/S0's - Kinematical classification into rotators/non rotators - Line strength maps - Central features/disks ubiquitous in E/S0's - etc.

NGC 4274 contains a central cold disk. This disk contributes the light above the exponential disk. The disk is dusty and younger. But also: Understanding of 'Pseudo-bulges' in spiral galaxies.

Observing parameter space NOT covered: 1. Other wavelength ranges: λ 5300A. Examples: -Studying young stellar populations in the UV -Studying detailed abundance ratios using many absorption lines -Studying star gas excitation and star formation using [OII], Hα 2. Higher spectral resolution (R > 1200) Examples: - Mass distribution and stellar populations in outer parts of spiral galaxies - Mass distribution and stellar populations in dwarf galaxies - Line profiles absorption and emission lines

Observing parameter space NOT covered: 3. Larger field of view Examples: -Measuring velocity dispersions in the outer parts of ellipticals to measure dark matter contents -Covering large galaxies at once for easier comparison with high-z galaxies 4. Different types of galaxies Examples: -interacting galaxies

3. Weijmans et al. (2009, SAURON) Measuring velocity dispersions at 4 r e (to get M/L ratios)

4. The Antennae Galaxies (HST) An IFU would be ideal to study many aspects of the interaction

Observing Mode 2: Using 20 mini-IFU's with diameters of about 10'', and sampling of about 1'' A. Resolved scaling relations in clusters of galaxies B. Studying scaling relations/galaxy evolution as a function of redshift

Scaling relations in the Coma Cluster (inspired by Russell Smith et al. 2009) Scaling relations can now be investigated Using the whole galaxy, or Using only the outer parts. Integral Field Spectroscopy gives all Ingredients for TF or FP relation at once!

Scaling relations might be much tighter when taking into account all galaxy light, rather than just the center SAURON E/S0 galaxies, Spitzer colours inside r e (left) and r e /8 (right); from Kutdemir & Peletier (2010)

The Tully-Fisher Relation at z~2 (Cresci et al. 2009, SINS (Genzel)) Integral Field Spectroscopy essential to measure regularity of velocity fields!

Spiral galaxies at z~0.5 fit very well into a mini-IFU with a size of 10''. Ideal to study TF-relation at z~0.5 (Kutdemir 2010, PhD Thesis Groningen)

Science Cases 3. Obtaining spectra for many objects across a large FOV A. Kinematics and stellar populations of galaxies in clusters B. Intracluster Planetary Nebulae