1. Stellar archaeology in the Milky Way Halo Variable stars and stellar populations in the new Milky Way satellites discovered by the SDSS Variable stars and stellar populations in the new Milky Way satellites discovered by the SDSS Ilaria Musella INAF – Osservatorio Astronomico di Capodimonte Napoli Clementini, Dall’Ora, Marconi, Ripepi, Greco, Di Fabrizio, Kinemuchi, Smith, Rodgers, Kuehn, Beers, Catelan, Pritzl

2.  -CDM hierarchical scenario ---> dSphs as Building Blocks of larger galaxies (such as the MW)  We should see remnants of this process  MW halo properties homogeneous with MW dSph satellites  -CDM hierarchical scenario ---> dSphs as Building Blocks of larger galaxies (such as the MW)  We should see remnants of this process  MW halo properties homogeneous with MW dSph satellites Galaxy formation mechanisms Galaxy formation mechanisms  Sgr dSph  CMa dSph/overdensity (debated)  Substructures in the M31 halo  Sgr dSph  CMa dSph/overdensity (debated)  Substructures in the M31 halo

3. Dwarf Spheroidal galaxies Old dSph’s Draco Ursa Minor Fornax Carina Sculptor LeoI LeoII Sextans Sagittarius Canis Major The impact of SDSS has been dramatic: 16 new objects have been discovered in the last years. The most numerous in the LG The most dark matter dominated Complex and unique SFH Metallicity (chemistry) Problem Variable Star Problem Missing Satellite Problem (MSP) new objects Bootes Bootes III Ursa Major Ursa Major II Canes Venatici I Canes Venatici II Coma Leo IV Leo T Hercules Bootes II Willman 1 Segue 1 Segue 2 Koposov I Koposov II new objects Bootes Bootes III Ursa Major Ursa Major II Canes Venatici I Canes Venatici II Coma Leo IV Leo T Hercules Bootes II Willman 1 Segue 1 Segue 2 Koposov I Koposov II

4. MW Inner 100 kpc

5. Milky Way satellites  Leo V  Boo II  Boo III

6. Old dSph’s GCs Dimensions --> Luminosity --> adapted from Belokurov et al. 2007 BooII K1 K2 And XII And XIII And XI SDSS GCs And XV And XVI  BooIII   Segue 2 SDSS dSph’s new objects Bootes Bootes III Ursa Major Ursa Major II Canes Venatici I Canes Venatici II Coma Leo IV Leo T Hercules Bootes II Willman 1 Segue 1 Segue 2 Koposov I Koposov II new objects Bootes Bootes III Ursa Major Ursa Major II Canes Venatici I Canes Venatici II Coma Leo IV Leo T Hercules Bootes II Willman 1 Segue 1 Segue 2 Koposov I Koposov II GCs dSph’s luminosity and mass limit of galaxy formation? …. or tidally disrupted remnants?

7.  Fainter than previously known dSph’s:  V > 28 mag/arcsec -2 (M v ~ -7 mag, r h ≥ 100 pc)  Properties intermediate between GCs and dSph’s (M v ~ -7 mag, r h ≥ 100 pc)  Darkest known stellar systems (M/L from ~35 to ~1000)  Metal poor (…as metal poor as stars in the MW halo)  Irregular shape  distorted  tidally interacting ~ 13 gyr)  Host an ancient population (t ~ 13 gyr)  RR Lyrae  Satellite deficit reduced to a factor 4 (Simon & Geha, 2007) New faint dwarf satellites: “building blocks” of the MW halo?

8. Looking for the “building blocks” of the MW halo In the MW, most of the GCs with an RR population sharply divide into two distinct groups, based on (Oosterhoff 1939) Oo I = 0.55 d OoII = 0.65 d In the MW, most of the GCs with an RR population sharply divide into two distinct groups, based on (Oosterhoff 1939) Oo I = 0.55 d OoII = 0.65 d And outside the Milky Way? And the old dSphs? And outside the Milky Way? And the old dSphs? Oo I Gap Oo II Oo I Gap adapted from Catelan, Greco et al. 2009, in preparation

9. Our projects: Which is the Oostehoff type of SDSS faint dSphs? Published Bootes I Canes Venatici I Canes Venatici II Coma Accepted Leo IV Telescope time: 1.5m Loiano, 1.8m Lowell, 2.2m ESO, WIRO, INT, TNG,SOAR, WHT We use time-series photometry for the listed galaxy to study the properties of their variable stars In progress UMa II Hercules Bootes II To observe Bootes III

10. ( α(J2000) 14:00:06 δ(J2000) 14:30:00 Ellipticity 0.33 0.7 R h 13′.0 ± 0′.7 V tot (mag) 13.6 ± 0.5 mag [Fe/H] -2.00 ± 0.07 mag (m-M) o 18.9 ± 0.2 mag revised 19.11 ± 0.08 mag revised 19.11 ± 0.08 mag D 60 kpc D 60 ± 6 kpc revised 66 ± 6 kpc revised 66 ± 6 kpc M V 0.5 mag M V -5.8 ± 0.5 mag μ V 28.3 ± 0.5 mag/arcsec -2 M/L 130-680 … along with the UMi dSph one of the most dark matter dominated object in the Universe! Belokurov et al. 2006 Dall’Ora et al. 2006, ApJL ( α(J2000) 14:00:06 δ(J2000) 14:30:00 Ellipticity 0.33 0.7 R h 13′.0 ± 0′.7 V tot (mag) 13.6 ± 0.5 mag [Fe/H] -2.00 ± 0.07 mag (m-M) o 18.9 ± 0.2 mag revised 19.11 ± 0.08 mag revised 19.11 ± 0.08 mag D 60 kpc D 60 ± 6 kpc revised 66 ± 6 kpc revised 66 ± 6 kpc M V 0.5 mag M V -5.8 ± 0.5 mag μ V 28.3 ± 0.5 mag/arcsec -2 M/L 130-680 … along with the UMi dSph one of the most dark matter dominated object in the Universe! Belokurov et al. 2006 Dall’Ora et al. 2006, ApJL Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress 11 RR Lyrae stars: 5 RRab’s, 5 RRc’s, 1 RRd, 1 LPV =0.69 d =0.37 d OoII

11. ( α(J2000) 13:28:03 δ(J2000) 33:33:21.0 Ellipticity 0.38 0.5 R h 8′.5 ± 0′.5 V tot (mag) 13.9 ± 0.5 mag [Fe/H] -2.09 ± 0.02 mag (m-M) o 21.75 ± 0.2 mag revised 21.62 ± 0.06 mag revised 21.62 ± 0.06 mag D 224 kpc D 224 +22/-20 kpc revised 210 +7/-5 kpc revised 210 +7/-5 kpc M V 0.5 mag M V -7.9 ± 0.5 mag μ V 28.2 ± 0.5 mag/arcsec -2 M/L 221 ± 108 Zucker et al. 2006 Kuehn et al. 2008, ApJL ( α(J2000) 13:28:03 δ(J2000) 33:33:21.0 Ellipticity 0.38 0.5 R h 8′.5 ± 0′.5 V tot (mag) 13.9 ± 0.5 mag [Fe/H] -2.09 ± 0.02 mag (m-M) o 21.75 ± 0.2 mag revised 21.62 ± 0.06 mag revised 21.62 ± 0.06 mag D 224 kpc D 224 +22/-20 kpc revised 210 +7/-5 kpc revised 210 +7/-5 kpc M V 0.5 mag M V -7.9 ± 0.5 mag μ V 28.2 ± 0.5 mag/arcsec -2 M/L 221 ± 108 Zucker et al. 2006 Kuehn et al. 2008, ApJL Variable Stars RRab (in red) RRc (in blue) Candidate AC (in purple) Variables without periods (in cyan) Variable Stars RRab (in red) RRc (in blue) Candidate AC (in purple) Variables without periods (in cyan) 4 Age Components 13 Gyr (red line) 5 Gyr (blue line) 1.5 Gyr (green line) 0.6 Gyr (black line) 4 Age Components 13 Gyr (red line) 5 Gyr (blue line) 1.5 Gyr (green line) 0.6 Gyr (black line) [Fe/H] = -2.1/-2.0 (ZW84/CG97) [Fe/H] = -2.1/-2.0 (ZW84/CG97) Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress RRab’s RRc AC 23 RR Lyrae stars: 18 RRab’s, 5 RRc’s 3AC 58 candidate variable (RR Lyrae?) =0.60 d =0.38 d Oosterhoff intermediate

12. RRab RRc ( α(J2000) 12:57:10 δ(J2000) 34:19:15 Ellipticity 0.3 R h 3′.0 V tot (mag) 15.1 ± 0.5 mag [Fe/H] -2.31 ± 0.12 mag (m-M) o 20.09 ± 0.2 mag revised 21.02 ± 0.06 mag revised 21.02 ± 0.06 mag D 151 kpc D 151 +15/-13 kpc revised 160 +4/-5 kpc revised 160 +4/-5 kpc M V 0.6 mag M V -4.8 ± 0.6 mag μ V 29.5 mag/arcsec -2 M/L 336 ± 240 Belokurov et al. 2007 Greco et al. 2008, ApJL ( α(J2000) 12:57:10 δ(J2000) 34:19:15 Ellipticity 0.3 R h 3′.0 V tot (mag) 15.1 ± 0.5 mag [Fe/H] -2.31 ± 0.12 mag (m-M) o 20.09 ± 0.2 mag revised 21.02 ± 0.06 mag revised 21.02 ± 0.06 mag D 151 kpc D 151 +15/-13 kpc revised 160 +4/-5 kpc revised 160 +4/-5 kpc M V 0.6 mag M V -4.8 ± 0.6 mag μ V 29.5 mag/arcsec -2 M/L 336 ± 240 Belokurov et al. 2007 Greco et al. 2008, ApJL Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress __ M15 _ _ M3 __ M15 _ _ M3 2 RR Lyrae stars: 1 RRab, 1 RRc Several candidate BSSs =0.74 d =0.36 d OoII

13. ( α(J2000) 12:26:59 δ(J2000) 23:54:15 Ellipticity 0.5 R h 5’ V tot (mag) 15.1 ± 0.5 mag [Fe/H] -2.00 ± 0.07 mag (m-M) o 18.2 ± 0.2 mag revised 18.02 ± 0.06 mag revised 18.02 ± 0.06 mag D 44 kpc D 44 ± 4 kpc revised 40 ± 1 kpc revised 40 ± 1 kpc M V 0.6 mag M V -3.7 ± 0.6 mag μ V 29.0 mag/arcsec -2 M/L 448 ± 297 Belokurov et al. 2007 Musella et al. 2009, ApJL ( α(J2000) 12:26:59 δ(J2000) 23:54:15 Ellipticity 0.5 R h 5’ V tot (mag) 15.1 ± 0.5 mag [Fe/H] -2.00 ± 0.07 mag (m-M) o 18.2 ± 0.2 mag revised 18.02 ± 0.06 mag revised 18.02 ± 0.06 mag D 44 kpc D 44 ± 4 kpc revised 40 ± 1 kpc revised 40 ± 1 kpc M V 0.6 mag M V -3.7 ± 0.6 mag μ V 29.0 mag/arcsec -2 M/L 448 ± 297 Belokurov et al. 2007 Musella et al. 2009, ApJL __ M68 _ _ M3 __ M68 _ _ M3 Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress 2 RR Lyrae stars: V1= RRab, V2= RRc, V3=short period variable =0.67 d =0.32 d OoII

14. 3 RR Lyrae stars: 3 RRab’s 1 SX Phoenicis (V4) =0.66 d OoII __ M15 ( α(J2000) 11:32:57 δ(J2000) -00:32:00 Ellipticity 0.25 R h 3’.3 V tot (mag) 15.9 ± 0.5 mag [Fe/H] -2.31 ± 0.10 mag (m-M) o 21.0 ± 0.2 mag revised 20.94 ± 0.07 mag revised 20.94 ± 0.07 mag D 158 +15/-14 kpc revised 154 ± 5 kpc revised 154 ± 5 kpc M V 0.6 mag M V -5.1 ± 0.6 mag μ V 28.3 mag/arcsec -2 M/L 151 ± 177 Belokurov et al. 2007 Moretti et al. 2009, ApJL, accepted ( α(J2000) 11:32:57 δ(J2000) -00:32:00 Ellipticity 0.25 R h 3’.3 V tot (mag) 15.9 ± 0.5 mag [Fe/H] -2.31 ± 0.10 mag (m-M) o 21.0 ± 0.2 mag revised 20.94 ± 0.07 mag revised 20.94 ± 0.07 mag D 158 +15/-14 kpc revised 154 ± 5 kpc revised 154 ± 5 kpc M V 0.6 mag M V -5.1 ± 0.6 mag μ V 28.3 mag/arcsec -2 M/L 151 ± 177 Belokurov et al. 2007 Moretti et al. 2009, ApJL, accepted Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress A Pair with Leo V? (Koch et al. 2008)

15. ( α(J2000) 16:31:02 δ(J2000) 12:47:30 Ellipticity 0.5 R h 8’.0 V tot (mag) 14.7 ± 0.5 mag [Fe/H] -2.27 ± 0.07 mag (m-M) o 20.7 ± 0.2 mag D 138 +13/-12 kpc M V 0.6 mag M V -6.0 ± 0.6 mag μ V 30.0 mag/arcsec -2 M/L 332 ± 221 Belokurov et al. 2007 Work in progress ( α(J2000) 16:31:02 δ(J2000) 12:47:30 Ellipticity 0.5 R h 8’.0 V tot (mag) 14.7 ± 0.5 mag [Fe/H] -2.27 ± 0.07 mag (m-M) o 20.7 ± 0.2 mag D 138 +13/-12 kpc M V 0.6 mag M V -6.0 ± 0.6 mag μ V 30.0 mag/arcsec -2 M/L 332 ± 221 Belokurov et al. 2007 Work in progress Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress

16. Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress ( α(J2000) 13:58:00 δ(J2000) 12:51:00 Ellipticity 0.21± 0.21 R h 4’.1 ± 1.6 V tot (mag) …. [Fe/H] -1.8 mag (m-M) o 18.1 ± 0.4 mag D 60 kpc D 60 ± 10 kpc revised 42 ± 8 kpc M V 1.1 mag M V -3.1 ± 1.1 mag revised -2.4 (-2.7) ± 0.7 (1.0) mag μ V 29.8 mag/arcsec -2 revised 28.4 mag/arcsec-2 ~ 35 M/L ~ 35 Wash et al. 2006, Wash et al. 2007 (confirmed dSph), Wash et al. 2009, Kock et al. 2008 (remnant in Sgr stream). Not clear nature Work in progress ( α(J2000) 13:58:00 δ(J2000) 12:51:00 Ellipticity 0.21± 0.21 R h 4’.1 ± 1.6 V tot (mag) …. [Fe/H] -1.8 mag (m-M) o 18.1 ± 0.4 mag D 60 kpc D 60 ± 10 kpc revised 42 ± 8 kpc M V 1.1 mag M V -3.1 ± 1.1 mag revised -2.4 (-2.7) ± 0.7 (1.0) mag μ V 29.8 mag/arcsec -2 revised 28.4 mag/arcsec-2 ~ 35 M/L ~ 35 Wash et al. 2006, Wash et al. 2007 (confirmed dSph), Wash et al. 2009, Kock et al. 2008 (remnant in Sgr stream). Not clear nature Work in progress

17. ( α(J2000) 08:51:30 δ(J2000) 63:07:48 Ellipticity 0.5 R h 13’.6 V tot (mag) 14.3 ± 0.5 mag [Fe/H] -1.97 ± 0.15 mag (m-M) o 17.5 ± 0.3 mag D 32 +5/-4 kpc M V 0.6 mag M V -3.8 ± 0.6 mag μ V 30.0 mag/arcsec -2 1 M/L 1722 ± 1226 Zucker et al. 2006 Work in progress ( α(J2000) 08:51:30 δ(J2000) 63:07:48 Ellipticity 0.5 R h 13’.6 V tot (mag) 14.3 ± 0.5 mag [Fe/H] -1.97 ± 0.15 mag (m-M) o 17.5 ± 0.3 mag D 32 +5/-4 kpc M V 0.6 mag M V -3.8 ± 0.6 mag μ V 30.0 mag/arcsec -2 1 M/L 1722 ± 1226 Zucker et al. 2006 Work in progress Variable stars in the new SDSS dSph’s Bootes I Dall’Ora et al, 2006, ApJL Canes Venatici I Kuehn et al. 2007, ApJL Canes Venatici II Greco et al. 2008, ApJL Coma Musella et al. 2009, ApJL Leo IV Moretti et al., 2009, accepted, ApJL Hercules in progress Bootes II in progress Uma II in progress 1 Rrab =0.66 d OoII

18. Summary: The SDSS new dSph’s in the Oosterhoff plane Bootes Canes Venatici I Canes Venatici II Coma LeoIV UMa II Oo II Oo Intermediate Oo II 15 RR Lyrae stars 48 “ 2 “ 1 “

19. The SDSS new dSph’s in the Oosterhoff plane Oo II Gap Oo I

20. Thank you