1 / 18

The Local Group

The Local Group. THE LOCAL GROUP. 35 - 40 members M31, and its satellites (red) Milky Way, and its satellites (blue) Isolated dwarfs (blue). Mass Length Time. Stellar Archaeology and Galaxy Genesis. DE + DM + VM. Mike Irwin.

syshe
Download Presentation

The Local Group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Local Group THE LOCAL GROUP 35 - 40 members M31, and its satellites (red) Milky Way, and its satellites (blue) Isolated dwarfs (blue) Mass Length Time

  2. Stellar Archaeology and Galaxy Genesis DE + DM + VM Mike Irwin • LR kinematic and general metallicity measures of main Galactic structures • detailed HR abundances of these to trace chemical development over time • LR analysis of surviving nearby galaxies and streams • exploit synergy with GAIA to break degeneracies

  3. Credit: Matthias Steinmetz

  4. Fine structure of simulated galaxies Abadi, Navarro, Steinmetz & Eke 2003 spheroid mass fraction thick disk thin disk age in Gyr

  5. Galaxy substructure and satellite accretion 38 30 23 CDM models predict large-scale subtructure in L galaxies like M31 and MW * Bullock & Johnston 2005 300 x 300 kpc

  6. Near-field cosmology - some key questions • where are the missing satellites? • are dark matter profiles universal? • what is the extent nature and spatial distribution of dark matter? • how were the Galaxy and M31 constructed? are they typical disk galaxies? • what was the role of accretion in the formation of the halo, disk, bulge? • what was the detailed chemical enrichment history of the stellar components?

  7. Galactic Science

  8. clusters galaxies Belokurov et al. 2006 AndXV AndXVI single stellar componentsno DM ? mulitple stellar components DM ? missing satellites ?? AndXIV AndXI AndXII AndXIII

  9. Missing satellites & Halo DM lumpiness Pal5 : Odenkirchen et al (2003)

  10. An accretion into the MW disk? • Heliocentric distance: • TRGB: 7.2 ± 0.3 kpc • 4-10 Gyr population • σ=12km/s (Martin et al 2004, 2005, Bellazzini et al. 2005)

  11. DART Canis-Major and the Monoceros Ring

  12. DART

  13. Galactic Science • chemo-dynamic structure of Galactic components - interface between disk, bulge/bar, halo - ancient dissolved and surviving substructures • fossil record of chemical evolution of stellar pops - chemical signature of ancient accretions - properties of metal-poor popIII stars • evolutionary history of stellar components - IMF, SFH, tagging the chemical development - the role of star clusters • linking the Bulge to the high Z universe • detailed chemo-dynamics of surviving satellites

  14. What do you need - I ? • wide field well calibrated imaging optical -> NIR • north: SDSS ugriz, WFCAM UKIDSS zyJHK • south: Skymapper, VST, CTIO 4m DES, VISTA • all-sky: 2MASS calibration and pathfinder • GAIA: proper motions and parallaxes • large area stellar spectroscopy (million stars) • automate majority of processing and analysis => logg, Teff, vel, [m/H]

  15. What do you need - II ? • large telescope with a wide fov eg. degrees diam • 1000-4000 fibres to exploit target surface density • survey selected regions totalling ~1000 sq deg • larger systematic survey find new structures • LR -> Mgb 4800-5500A and CaT 8150-8850A vels to < 10 km/s; [Fe/H] to 0.1-0.2 dex; limited chemical tagging e.g. [alpha/Fe] ? • synergy with GAIA => LR to ~V=20 => full 6D kinematic phase space information

  16. GA substructure with LAMOST + • dsphs and “dark” satellites eg. UMaI, UmaII ...... • tidal streams eg. GCs; dSphs; orphan streams • open clusters and unbound debris • known halo/disk sub-structures eg. Triang-And-Perseus; Sgr stream; Hercules-Aquila cloud; Arcturus group ....... • outer disk eg. warp -v- Canis Major edge of, outer spiral arm structure

  17. DART LAMOST and GA competition

  18. Summary • large area spectroscopic studies of nearby galaxies are needed to test cosmological predictions on low-mass scales • nature and distribution of dark matter • detailed formation history of galaxies • GAIA will revolutionise this field, but will lack detailed chemical information, as well as accurate radial velocities

More Related