Photometric and spectroscopic properties of stellar populations in

Photometric and spectroscopic properties of stellar populations in the Carina d. Sph galxy M. Monelli Instituto de Astrofìsica de Canarias Concepcion, Jan 8 -14, 2007

• Spirals • d. Sph/d. E S. Hidalgo • d. Sph/d. Irr • d. Irr

An example: the field of IC 1613 Rt~15' ACS

1. An example: the field of IC 1613 Rt~15' ACS + Subaru I. Drozdovski

An example: the field of IC 1613 Rt~15' ACS + Subaru + CFHT

(m-M)0 D(Kpc) Mv (TO) Rcore (') Rtidal (') Galaxy satellites 18. 5 -22 50 -250 22. 5 -26 6 -16 10 -80(? ) M 31 satellites 23. 5 -24. 5 500 -800 27 -28. 5 <3 5 -17 Isolated <26 <1600 <3 <5 North telescope Mirror (m) Obs type F. o. v. Suprime. Cam SUBARU 8 Imaging 30'x 24' Prime. Focus WHT 4. 2 Imaging 16'x 16' Mega. Cam CFHT 3. 6 Imaging 1°x 1° WFC INT 2. 5 Imaging 34'x 34' VIMOS VLT 8 Ima/spec 16'x 18' MOSAICII CTIO 4 Imaging 36'x 36' WFI 2. 2 ESO 2. 2 Ima/spec 33'x 34' FORS 1/2 VLT 8 Ima/spec 7'x 7' FLAMES VLT 8 Spec 25'x 25' ACS HST 2. 4 imaging 3'x 3' South

TO star, Mv~3. 5 S. Hidalgo D~200 Kpc, (m-M)=21. 5 mv(TO)~25 D~770 Kpc, (m-M)=24. 5 mv(TO)~28 D~2 Mpc, (m-M)=26. 5 mv(TO)~30

Use different approaches! • 4 m telescopes + wide-field imagers • 8 m telescopes + medium-field cameras • HST + spectroscopy (8 m + multi-object spect. ) Global understanding of the properties of nearby galaxies (SFH, variables, radial gradients, tidal interactions…)

Carina: Observational issues Ø Extended Ø low surface brightness Ø low central density (m-M)0 ~ 20. 15 D ~ 100 Kpc Mv ~ -9. 3 Rcore ~ 9 Rtidal ~ 29 (47’) (Mateo 1998) 1°x 1° DSS WIDE FIELD OBSERVATIONS!!

Why Carina? • complex star formation history (Smecker-Hane et al. 1996) ( mix of stellar populations) • recent episode (<1 Gyr) (Monelli et al. 2003) • sizable sample of variable stars (Dall’Ora et al. 2003) • high M/L ( ~30 M☼ /L☼) DM? • controversial evidence of extra-tidal stars: tidal interactions with the Galaxy or extended halo ? (Hayashi et al 2003, Kazantzidis et al 2004, Monelli et al. 2004, Munoz et al. 2006)

The Carina Project: Long term photometric and spetroscopic project aimed at studying the stellar content of the Carina d. Sph galaxy • G. Bono, R. Buonanno, V. Castellani, C. E. Corsi, F. Caputo, L. Pulone (INAF-Rome Obs. ) • A. R. Walker (CTIO) • M. Dall’Ora, V. Ripepi (INAF-Capodimonte Obs. ) • A. Munteanu (Univ. Pompeu Fabra) • P. B. Stetson (DAO) • H. A Smith (MSU) • M. Nonino (INAF-Trieste) • A. Aparicio, C. Gallart (IAC) • F. Thévenin (Nice Obs. ) • P. Francois (Paris Obs. )

The data set: central region Instr. f. o. v. Filter Tot. exp. Date 2. 2 m ESO 32 x 33 60 B 30, 500 s 5 -7 Jan 2000 CTIO 4 m 0. 23 /px 36 63 V 54 B 30, 300 s + archive 21, 200 s 19 Dec 1999 0. 27 /px 54 V 22 U 19 I 13, 000 s 8 -9 Jan 2000 22, 000 s Dec 2004 5, 700 s Jan 2005 • Photometric reduction with DAOPHOTII/ALLFRAME (Stetson 1987, 1994) ~2, 900 frames WARNING!!! CAREFUL WITH THE CALIBRATION!!

Results: color-magnitude diagram ~30000 stars (|sharp|<0. 2) DM = 20. 24 E(B-V) = 0. 03 Z = 0. 004 [Fe/H] = -1. 7 isochrones superposition: Old population ~11 Gyr Intermediate pop. ~3 -7 Gyr Young pop ~0. 6 -1 Gyr

Results: spatial distribution The intermediate-age stellar population is more concentrated toward the centre; old stars are distributed in a sort of diffused halo. The peak of the distribution of the old stars is offset by ~2´.

Spectroscopic data sets GIRAFFE RA DEC 1 06: 41: 37 -50: 57: 58 2 06: 41: 00 -50: 45: 06 3 06: 42: 51 -50: 52: 50 4 06: 39: 50 -51: 04: 00 5 06: 42: 05 -51: 10: 00 06: 42: 03 -50: 54: 00 λ(nm) tot # stars 18 LR 8 820 -940 (Ca. T) R~6500 exp time (hr) ESO archive 1100 (RGB, AGB + field) 15 10 7. 5 16 FORS 2 A A - - B 06: 42: 00 -50: 30 C 06: 41: 38 -50: 55: 34 D 06: 41: 26 -51: 57: 30 E 06: 40: 51 -51: 07: 56 1028 z (Ca. T) 773 -930 2. 6 330 2. 9 1400 V 456 -586 (Mg triplet) R~2000 2. 9 5 2. 9 1. 3 (RGB, HB, MS, TO, variables + field)

FLAMES (archive): based on EIS photometry (Koch et al. 2006) FORS 2: based on our photometry Complementary samples

Two main questions: 1) Do the different populations present different kinematical properties? 2) Is there any spread in the chemical composition among different populations?

WARNING!! FLAMES: Uncertainties in sky subtraction: partially masked in the vr determination but show up with the individual abundance determination FORS 2: 1) day/night mask positioning abundances 2) Centroid positioning in the slit vr

FLAMES (1095) FORS 2 (150) Work in progress… Different peak? ? Hidden systematics? ?

Variable Stars • Multiple stellar populations different families of variable stars present in the same system, both in H- and He-burning phases • Bright variables as tracers of stellar populations

19 Anomalous Cepheids

19 Anomalous Cepheids 79 RRLyrae

19 Anomalous Cepheids 79 RRLyrae 13 binaries

19 Anomalous Cepheids 79 RRLyrae 13 binaries 270 candidates/unclassified

Outer fields: tidal tails? We observed selected regions around Carina. Deep images were collected in order to use Main Sequence stars as tracers of the stellar content. CTIO 4 m 2. 2 m ESO C, D B E A α, β γ 30' 52' 60' 1. 5 ˚ 2˚ 4. 5˚

Conclusions ü USE DIFFERENT APPROACHES!!