1. Chemo-dynamics of galaxies with resolved stellar populations: now and then Giuseppina Battaglia Instituto de Astrofisica de Canarias, Tenerife Credit: ESO/H.H.Heyer Credit: ESO/L. Calçada Karachentsev et al. 2014

2. Individual Red Giant Branch stars & CaII triplet intermediate resolution spectroscopy Gallart et al 2005 -Tracers of galaxy evolution from recent epochs back to the oldest times -Bright! Brightest feature in old stellar pop. At low/ intermediate resolution (R ~ 3000-6000) -> short(ish) exposure times: -KINEMATICS: Velocities accurate to a few km/s -CHEMISTRY: Calibration CaT EW – [Fe/H] OVER A WIDE [Fe/H] RANGE (e.g. Rutledge et al. 1997, Cole et al. 2004, Battaglia et al. 2008, Starkenburg et al. 2010, Carrera et al. 2013 etc.) Starkenburg et al. 2010

3. Credits: M.Mateo McConnachie 2012 Dwarf galaxies: even the simplest galaxies are complex

4. Credits: M.Mateo McConnachie 2012 Milky Way Dwarf spheroidals & VLT/FLAMES Phoenix transition type & VLT/FORS NGC6822 dwarf irregular & VLT/MUSE Early-typesLate-types Figure credits: McConnachie 2012; Mario Mateo; Stephen Leshin; Local Group Survey Team; Lowell Observatory Dwarf galaxies: even the simplest galaxies are complex

5. Spatial variations of metallicity properties Sculptor dSph (Tolstoy et al. 2004, Battaglia et al. 2008) Fornax dSph (Battaglia et al. 2006, 2008) Sextans dSph (Battaglia et al. 2011) [Fe/H] from CaT lines calculated using the calibration from Starkenburg et al. 2010 (see also e.g. Koch et al. 2006; Faria et al. 2007; Gullieuszik et al. 2009; Kirby et al. 2011) Phoenix dT (Kacharov, Rejkuba, Battaglia et al. in prep) r tid r core r tid r core r tid 180 mem 600 mem 850 mem

6. A “centrifugal barrier” mechanism? Phoenix Pegasus Leaman et al. 2013 Non-rotating Rotating Less massive (Mdm ~ 5 x 10^8 Msun) More massive (Mdm ~ 3 x 10^9 Msun) Schroyen et al. 2011 Interesting to analyze dIrrs and dTs as a function of mass and angular momentum; we are starting to populate the parameter space

7. MP MR “Metal-rich” [Fe/H] > -1.5 “Metal-poor” [Fe/H] < -1.7 Multiple stellar components & dark matter: Sculptor (found also in Fornax and Sextans) Battaglia et al. (2008) -Kinematics of multiple stellar components prefer a cored profile to a cuspy one (Battaglia et al. 2008) -Not possible to make a distinction when treating the stars as 1 component -Results confirmed by other groups (Walker & Peñarrubia 2011; Amorisco & Evans 2012) Cored _____ Cusped - - - - No selection in [Fe/H] Line-of-sight velocity dispersion profiles:

8. VLT/FORS: Tolstoy et al. 2001 VLT/FLAMES: Tolstoy et al. 2004, Battaglia et al. 2006, 2008, 2011, Starkenburg et al. 2010 Much wider range of [Fe/H] values within each galaxy than previously thought -> this should give indications on the galaxy’s capability to retain its ISM -> potential well Presence of (rare) extremely metal-poor stars (see also Kirby et al. 2009, Frebel 2010, Tafelmeyer et al.2010) Sculptor Fornax Large number statistics is important ! Sculptor Fornax

9. Spatially extended vs centrally concentrated samples

10. Kirby et al. 2010, 2011

11. Can we carry out similar observations out to the distance of the Virgo cluster using the E-ELT + HARMONI ? GENERAL AIM: [Fe/H] (±0.3dex) and line-of-sight velocities (±20 km/s for large galaxies, 5km/s for dwarfs) from the CaT lines for about 1000 individual RGB stars in a “reasonable” observing time out to a few Mpc (Virgo?) In the E-ELT era: Simulations within the Design Reference Mission Credit: ESO/L. Calçada

12. Objects and Distance range: Generalities ~1 Mpc (LG: NGC205) 4 Mpc (CenA) 17 Mpc (Virgo: M87) Tip of the RGB in I-mag at ~: 20.6 23.9 27.2 Target RGB + stellar background from mock stellar population yielding a given surf. brightness (code by J. Liske) Constant SFH (14-12Gyr) [Fe/H] = -1.7 (MP) [Fe/H] = -1.0 (MR) Spectra from the Munari et al. 2005 synthetic spectral library

13. R = 4000 & 9000 Instantaneous field-of-view = 5” x 10” Spatial pixel (spaxel) size = 40 mas x 40 mas 35% instrument throughput 18% Encircled Energy in one spaxel in I- band Instrumental and technical adopted characteristics INSTRUMENT (adapted to HARMONI) TECHNICAL PARAMETERS Exposure time (20min to 50h) Site (Paranal-like; High&Dry) Mirror coating (bare Al; Ag/Al) Zenith & seeing = 0.8” Diameter = 42m (to be updated to 39m)

14. 2 Re ≈ 12 kpc (23.7 mag/arcsec^2) 5 Re ≈ 30 kpc (26.3 mag/arcsec^2) 5”5” Centaurus A [Fe/H]=-1 ; target RGB 0.5 mag below tip (I= 24.4) No crowding at these distances at the explored mag. High&Dry; Ag/Al R=4000&9000

15. Centaurus A [Fe/H] and vel requirements fulfilled in 1h considering the flux in only 1 spaxel! EE= 18%: -> seeing 0.6” If EE=9% -> exp. time x 4 In reality we will recover the flux over multiple spaxels Numb RGB stars per pointing (I <= tip – 0.5mag): 1Re = 75 2Re = 16 3.5Re= 4 -> well feasible to observe 1000 target RGBs

16. M87/Virgo [Fe/H]=-1 ; target RGB at the tip (I= 27.2) Some crowding already at 4Re (22.2 mag/arcsec^2) Critical to explore options to use more spaxels (ala Kammann et al.) Most likely observations limited to a few pointings

17. Summary Even small systems like dwarf galaxies are complex (e.g. metallicity gradients, large range of [Fe/H], multiple-stellar components, rotation etc.). Large number statistics and spatial coverage are important (even more so for larger/more complex galaxies) Intermediate res. Spectroscopy of large numbers of individual RGB stars in the nIR CaT region with E- ELT+HARMONI: Well feasible out to a few Mpc (e.g. CenA) Much more time consuming at the distance of Virgo

18. Caveats Simulations assumed “perfect” data reduction. Only 1-D spectra simulated. No effect of airmass; just one seeing Only one spaxel considered and for completely resolved stars Restricted range of SFHs/target types (RGBs)/only CaT Next Steps HARMONI simulator (DATA CUBES) Explore options to deal with crowding and extract flux from more spaxels (e.g. as Kammann et al.) Actual IFU observations of Local Group systems

19. Resolved stellar population studies with IFUs: NGC6822 dIrr @ VLT/MUSE (PI: Mendel) D= 490kpc Star-forming and gas-rich MV= -15.2 Pointing: Surf. Bright V ~ 20.8 mag/arcsec^2 ~ half-light radius 1’ x 1’, 0.2”/pixel (0.3”-0.4” FWHM) R = 1700 (480nm) – 3600 (930nm) 1.5h on source “BVI” MUSE image

20. Resolved stellar population studies with IFUs: NGC6822 dIrr @ VLT/MUSE (PI: Mendel) 192 sources 288 sources Data reduction mostly with ESO pipeline Source extraction/sky-subtraction with PampelMUSE (Kammann et al. 2013)