Bershady Verheijen Westfall Martinsson Swaters Andersen The Disk-Mass Survey Bershady Verheijen Westfall Martinsson Swaters Andersen goals: - obtain radial surface-density profiles Σ(r) of galaxy disks - determine M/L of stellar populations in disks - break disk-halo degeneracy in rotation curve decompositions - get ρDM(r) method: measure vertical stellar velocity dispersion σ data: R≈10 spectroscopy of MgIb & CaII at ≤ 3 R (μ =24.5) two custom-built wide-field fiber-based IFUs (SparsePak, P-Pak) sample: ∼40 nearly face-on (incl=25°- 35°), kinematically regular spirals range in morphology, mass, color, surface brightness, SF rate ... z 4 disk B

SparsePak P-Pak UW - Madison AIP - Potsdam 3.6m WIYN, Kitt Peak 71"x72" field of view 82 fibers (4.7" ∅) 75 science, 7 sky R≈10.000 (Hα, MgIb, CaII) 3.5m CAHA, Calar Alto 64"x74" field of view 382 fibers (2.7" ∅) 331 science, 36 sky, 15 calib. R≈8.000 (MgIb, Hα/Hβ/Hγ)

IFU spectroscopy : azimuthal averaging to gain S/N UGC 6918 HST/WFPC-2 P-Pak : MgIb SparsePak : Hα (3-point dither) MgIb, CaII

Sample & Strategy optical (SDSS) 400 galaxies pre-selected from UGC Hα velocity fields (SparsePak) 8 micron (Spitzer) 50 kpc 2 arcmin Sample & Strategy 400 galaxies pre-selected from UGC type, size, inclination, visually inspected non-interacting, non-barred Hα velocity fields of 130 randomly chosen spirals Subsample of 40 spirals with - regular Hα velocity fields - stellar kinematics (MgIb, CaII) - optical imaging (U,B,V,R,I) - near-IR imaging (J,H,K) - Spitzer imaging (4.5,8,24,70μm) - HI & 1.4 GHz continuum (ongoing)

photometry Hα velocity field stellar VF & LOSVD U6918

Ongoing work & some results Important (and time-consuming) issues: Registration: refine the pointings of the dithered Hα velocity field observations Flexure issues (shifts, scale differences & rotations) Decompose vel.disp ellipsiod (σr, σφ, σz) Westfall et al (astro-ph/0801.4912) Careful error propagation and understanding the error budget