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A Carbon Star Survey in the Local Group galaxies

A Carbon Star Survey in the Local Group galaxies. battinel@oarph1.rm.astro.it. Roma, 4 Novembre 1868: the Beginning!. A Carbon Star Survey in the Local Group galaxies. CS as standard candles CS as tracers of low density halos & tidal tales CS as kinematical probes. Contents:.

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A Carbon Star Survey in the Local Group galaxies

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  1. A Carbon Star Survey in the Local Group galaxies battinel@oarph1.rm.astro.it

  2. Roma, 4 Novembre 1868: the Beginning!

  3. A Carbon Star Survey in the Local Group galaxies • CS as standard candles • CS as tracers of low density halos & tidal tales • CS as kinematical probes Contents: battinel@oarph1.rm.astro.it

  4. Standard CandlesTheory Evolutionary models of stellar systems suggest that <Mbol> of CS does not depend on the metallicity. (see e.g. Mouhcine&Lançon, 2003) • Powerful standard candles: • brighter than Cepheids; • single epoch of observation; • reduced absorption (NIR); • brighter than the TRGB.

  5. hard to draw conclusions Standard Candlesobservations • absolute magnitudes of CN stars span over 8mag !! • (Knapp et al. 2000) • cool red-giant size ~10mas with spatial and temporal variation in surface brightness

  6. Four Band Photometric System • Palmer & Wing (1982) • Cook & Aaronson (1989) • Richer et al. (V,I,CN,TiO) • B&D (R,I,CN,TiO)

  7. Standard Candlesresults from our ongoing survey When CS are carefully and homogeneously identified (FBPS in our survey): • <MI> independent of [Fe/H] • <MI> scatter for faint galaxies

  8. Intermediate-age halo First detection! Low-Density Environment Tracersresults from our ongoing survey The case of NGC 6822 and its extended halo…. … of old and intermediate age stars.

  9. Low-Density Environment Tracersresults from our ongoing survey exp. disk: 2.96± 0.14 arcmin minor axis: 4-5 arcmin … and the missing halo of NGC 3109…

  10. About 500 CS identified (2003, AJ June) Low-Density Environment Tracersresults from our ongoing survey … the tidal debris around NGC 205.

  11. Low-Density Environment Tracersresults from our ongoing survey … the tidal debris around NGC 205. Extratidal stars NW of NGC 205

  12. Kinematical Probesfollow-up of our survey the stellar rotation curve and the mass of Andromeda galaxy • 900 CS identified along the SW major axis from 17 to 30 (2003 AJ, 125, 1298) • extention up to 40 kpc (TNG-QSO, July 03)

  13. Kinematical Probesfollow-up of our survey the stellar rotation curve and the mass of Andromeda galaxy • 900 CS identified along the SW major axis from 17 to 30 (2003 AJ, 125, 1298) • extention up to 40 kpc (TNG-QSO, July 03) 20 kpc = 80' 30 kpc = 130' 40 kpc = 180'

  14. Kinematical Probesfollow-up of our survey the stellar rotation curve and the mass of Andromeda galaxy Gemini N TNG • beyond 30kpc only 2 GCs and none PN • this will provide the largest lower estimate of the mass of M 31

  15. Kinematical Probesfollow-up of our survey … the monstrous MegaPrime

  16. Kinematical Probesfollow-up of our survey CS: e.g. Margon et al. 2002 … the monstrous MegaPrime

  17. CS survey in the Local Group IC 10

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