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Near-Field Cosmology with the GMT

Near-Field Cosmology with the GMT. Myung Gyoon LEE (K-GMT SWIG/ Seoul National University ). GMT2010:Opening New Frontiers with the GMT 2010.10.4-6, Seoul National University, Korea. Cosmology in 21C. Structure & dynamics of the Universe Structure formation

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Near-Field Cosmology with the GMT

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  1. Near-Field Cosmology with the GMT MyungGyoon LEE (K-GMT SWIG/Seoul National University) GMT2010:Opening New Frontiers with the GMT 2010.10.4-6, Seoul NationalUniversity, Korea

  2. Cosmology in 21C • Structure & dynamics of the Universe • Structure formation • Mass assembly & Star formation • Dark matter • Dark energy Komatsu et al (2008, 2010)

  3. Concordance Cosmology (21C) • ΛCDM + Hierarchical Merging Model • Successful for large-scale structures and CMBR N-body simulation By Park (2005) Power spectrum (Tegmark et al 2004)

  4. Near-Field Cosmology in 21C • Structure & dynamics of the U? • Small-scale structure formation • Mass assembly & Star formation • Dark matter • Dark energy?

  5. Concordance Cosmology (21C) • LCDM + Hierarchical Merging model • But, problems for small-scales • Small-scale problems are not at all small, but big! Power spectrum (Tegmark et al(2004))

  6. Issues for Near-Field Cosmology • Problems in ΛCDM+HM model 1)Missing satellite problem 2) Star formation problem 3) Galaxy core/cusp problem 4) Thin disk galaxy problem

  7. GMT Near-Field Cosmology • To over current barriers with the power of the GMT • High resolution deep imaging+spectroscopy • (NIRMOS, GMACS, GCLEF, GMTNIRS, GMTIFS etc) • To complement with Skymapper, DES, LSST, JWST, etc. • Targets: dwarf galaxies and globular clusters

  8. Dwarf Galaxy Cosmology • Dwarf galaxies • are dark-matter dominated • are made of various stellar pops • can be studied in most detail • Cosmological topics with dwarf galaxies • To study dark matter • To study the early star formation history • To find the first objects in the universe

  9. Globular Cluster Cosmology • Globular clusters • are a good tracer of dark matter • have a large range of metallicity • are found in galaxies & between galaxies • are bright: an efficient tool for local galaxies • Cosmological topics with globular clusters • To study dark matter in galaxies and clusters • To study the formation of their host galaxies • To find the first objects in the universe

  10. GMT Near-Field Cosmology 1) Dwarf galaxy cosmology 2) Globular cluster cosmology

  11. Dwarf Galaxy Cosmology #1 • Dark matter • To understand the missing satellite problem • 1) N(obs satellites) >> N(mini-halo in model) • 2) Mmin(obs satellites) >>Mmin(mini-halo) Comparison of mass functions for the MW dSphs and Via Lactea II simulation (Bullock 2010)

  12. To Find Dark Galaxies • Segue 1: the darkest galaxy with M/L=3400 (M~106Mo, but L=340 Lo), very small (re=30 pc), • very metal poor ([Fe/H]=-2.5) • Geha et al (2009), Simon et al (2010), Martinez et al (2010)

  13. Mv-Siz Relation for Dwarf Galaxies • Dark galaxies have low surface brightness, small size, but some mass! • They may be ‘satellites of (dead) satellites’ (Belokurov et all 2009) UCD dSph Mv Mv-log re(pc) for dwarf galaxies, globular clusters, and UCDs. Most of the new dwarfs (filled circles) are from SDSS. (???? 2010) GC Log re[pc]

  14. M/L for dwarf galaxies • M/L increases as dSph galaxies get less massive, smaller, and fainter. Tellerud et al (2010) dSph

  15. Search for Dark Galaxies • MW satellites mostly in the northern sky (POSS, SDSS) • Where are missing satellites? • To survey the southern sky • Soon: Stromlo Missing Satellite Survey (SMSS) with Skymapper • Later: DES, LSST Distribution of MW satellites (Jerjen 2010)

  16. Survey of Dwarf Galaxies at <1Mpc • Detection: wide field imaging for survey (LSST etc) • GMT follow-up: deep photometry & spectroscopy (member selection, age, metallicity, kinematics, mass, etc) Distance [kpc] GMT targets • N(R<400kpc)

  17. Dwarf Galaxy Cosmology #2 • Star formation history • To understand star formation problem • The duration of the first star formation in dwarf galaxies is extended (e.g., Lee et al 2009, Monelli et al 2010). • To find when and how long the first stars form S FH of MW dSphs (Grebel 2005)

  18. First star formation in LG • LCID: Deep HST • photometry of six • isolated galaxies • (Monellietal (2010), • Tolstoy etal (2009)) • Go deeper with the GMT • to derive the first star formation precisely! • Why not 100m-1000m telescopes? • Time to start for them?

  19. What about beyond the LG? • Still tough, but can dig older stars with the GMT! Tolstoy etal (2009) Very metal poor!

  20. Dwarf Galaxy Cosmology #3 • The First Objects (Pop III?) • To find the most metal-free stars (the oldest stars?) • Where are they? • In the outskirts or center of a massive galaxy? • In dwarf galaxies? • In globular clusters?

  21. Search for the Most Metal-poor Stars • Where are the most metal-poor stars? • [Fe/H], M/L/, M versus L for MW dSphs indicates • In the faintest dSphs (the most dark-matter dominated)! (2009)

  22. A History for the Most Metal-poor Stars • Frebel 2010’s prediction:

  23. Globular Cluster Cosmology • To study dark matter in galaxies and clusters • To study the formation of their host galaxies • To find the first objects

  24. Globular Cluster Cosmology #1 • Dark matter in Galaxies • Kinematics-> Dark matter distribution in their host galaxies • Age & metallicity -> formation of their host galaxies

  25. Kinematics of GCs in Galaxies • A summary of gE GC kinematics: diversity(Lee et al (2010a) • GMT spectroscopy of GCs • (radial velocity, [Fe/H], [alpha/H]) Harris (2009) CFHT/Megaprime: 1d x 1d for M87 GC SDSS IGC GMT spec

  26. Globular Cluster Cosmology #2 • Dark matter in Galaxy Clusters • Kinematics of intracluster globular clusters (IGCs)-> Dark matter distribution in galaxy clusters

  27. IGCs in the Virgo Cluster • Large scale structure of GCs in Galaxy Clusters • (Lee et al 2010b, Science) • GMT spectroscopy of IGCs • (radial velocity, age, metallicity)

  28. Globular Cluster Cosmology #3 • To find the first objects • Some of the IGCs may be the first objects! • GMT Spectroscopy and deep photometry

  29. Are IGCs really GCs? IGC-HST search

  30. IGCs in the Virgo *HST/ACS images: They are genuine GCs! -Williams et al (2007) 4 IGCs in Area 4 -Lee, Lim, et al (2010, in prep) several new IGCs Are they really GCs? How about compact dwarfs (UCDs, DTGCs)?

  31. Dwarf Galaxies vs GCs • Do they belong to the same class? • Which of them are the first objects? GC UCD dSph Faber-Jackson relations from GCs to galaxy clusters. (Tellerud et al 2010)

  32. The first objects are GCs? • 1968 Peebles and Dicke’s suggestion. • With the GMT, we can test it!

  33. Summary for GMT Near-Field Cosmology With the GMT observations (GMACS, NIRMOS, Gclef, GMTNIRS, GMTIFS, etc) of dwarf galaxies and globular clusters, we can 1) study dark matter in galaxies and clusters 2) study the early star formation history 3) find the first objects in the universe

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