The contribution of the Sgr dSph to the globular Cluster System of the Milky Way Recovery of the original conditions of the Sgr dSph Michele Bellazzini – INAF Bologna Observatory Rodrigo Ibata – Observatoire de Strasbourg Francesco R. Ferraro – Bologna University

Michele Bellazzini – La Palma, May 2003 GCs along the Sgr orbit The Galactic GC with R_GC > 10 kpc correlates with the Sgr orbit (as modeled by IL98) in the X,Y,Z,V_r phase space The Galactic GC with R_GC > 10 kpc correlates with the Sgr orbit (as modeled by IL98) in the X,Y,Z,V_r phase space At least 4 GC have to be associated with the Sgr Stream At least 4 GC have to be associated with the Sgr Stream A list of possible (ranked) candidates: Pal 12, NGC 4147, NGC 5634, Pal 5, NGC 5053, NGC 5466, NGC 288, NGC 6426, Pal 2 etc. A list of possible (ranked) candidates: Pal 12, NGC 4147, NGC 5634, Pal 5, NGC 5053, NGC 5466, NGC 288, NGC 6426, Pal 2 etc. Bellazzini, Ferraro & Ibata, 2003, AJ, 125, 188

Michele Bellazzini – La Palma, May 2003 Testing the hypothesis using 2MASS The use of M stars in (K,J-K) to trace Sgr stars was firstly introduced by Ibata et al. (2002) using the 2nd DR of 2MASS Stars in the upper RGB of Sgr stand out with respect of Galactic foreground stars in the (K,J-K) CMD Reporting the Selection Box in the CMD of other fields we can check if there is any excess of “Sgr-like” M stars. The shift applied to the SB to match the observed sequence provide a differential estimate of distance

Michele Bellazzini – La Palma, May 2003 Testing the hypothesis using 2MASS Bellazzini, Ibata, Ferraro & Testa, 2003, A&A, in press (astro-ph/03xxxx, subm. Feb 03, accept. April 24, 03) 1.Select a wide field around the target cluster and a suitable Control Field 2.Shift the SB in both CMD and count stars falling into 3.Compute the normalized difference, find the maximum, check statistical significance 4.With 2nd DR test possible only for Pal 12 and NGC Other candidates: insufficient field Confirmation of the detection by Martinez-Delgado et al. with MS stars Pal 12 and NGC 4147 are immersed into the Sgr Stream

Michele Bellazzini – La Palma, May 2003 Testing the hypothesis using 2MASS Another example: NGC 5634 The Sgr Stream is kpc behind the cluster in this direction The angle between the line of sight and the orientation of the Stream has an impact on the efficiency of the technique

Michele Bellazzini – La Palma, May MASS All Sky: the global view Selection of M giants and photometric parallax on the entire 2MASS catalogue as in Majewski & 2MASS team (2003) YZXYXZ The perspectives of the near future (present?)…

Michele Bellazzini – La Palma, May 2003 A census of candidate Stream members There are 7-8 good There are 7-8 good candidates in the part of the Stream that is well traced by M giants: simply check Vr With refined models we can search in other parts of the Stream traced by older stars (maybe)

Michele Bellazzini – La Palma, May 2003 The old & metal-poor population in Sgr The early epoch of star formation in Sgr and in the Stream can now be traced with clusters AND field stars See poster by Monaco et al. Counterpart of the BHB found by Newberg et al in the S field

Michele Bellazzini – La Palma, May 2003 Candidate Stream GCs vs Sgr members Most of the best candidates are faint, loose and metal-poor clusters similar to Ter 8 and Arp 2

Michele Bellazzini – La Palma, May 2003 An interesting case: NGC sigma signal in a 30 deg X 20 deg field The cluster is 3 kpc behind the detected peak of the signal. Also NGC 7492 is immersed in the Sgr Stream.

The contribution of the Sgr dSph to the globular Cluster System of the Milky Way Recovery of the original conditions of the Sgr dSph Rodrigo Ibata (Obs. Strasbourg); F.R. Ferraro (Bologna Univ.) V. Testa (Roma Obs.); L. Monaco (Bologna Univ.)

Wide field photometry The evolved population Distance (RGB Tip) Chemical evolution (spectroscopy) Our group: Bellazzini, Ferraro, Monaco, Pancino, Origlia

Wide Field Photometry for 16 LG galaxies Bellazzini et al. 2002, AJ, 124, 3222

Bellazzini et al. 2001, MNRAS, 327, L15 Bellazzini et al. 2002, AJ, 124, 3222 Monaco et al., 2002, ApJ, 578, L47

Globular clusters in the SGR stream Our group: Bellazzini, Ferraro, Monaco, Ibata (Strasbourg) Bellazzini, Ferraro & Ibata, 2002, AJ, 124, 915 Bellazzini, Ferraro & Ibata, 2003, AJ, 125, 188