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Timewaste-o-Vision. IN GLORIOUS. Nubecula Major. Adric Riedel. Outline. Basic Facts Discovery Morphology Its place in the Local Group Relation to the Small Magellanic Clouds As compared to other galaxies The Past and Future of the LMC Dark Nebulae Terminal spiral into Milky Way
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Timewaste-o-Vision IN GLORIOUS Nubecula Major Adric Riedel
Outline • Basic Facts • Discovery • Morphology • Its place in the Local Group • Relation to the Small Magellanic Clouds • As compared to other galaxies • The Past and Future of the LMC • Dark Nebulae • Terminal spiral into Milky Way • What we’ve learned from the LMC • Star-forming regions • Spiral Nebula • Superbubbles! • 30 Doradus • SN 1987a • Where SN1987a is
History of the LMC Discovered even earlier by everyone who lived in the southern hemisphere Discovered in 1519 by Ferdinand Magellan Discovered in 964 by Abd-Al-Rahman Al Sufi Discovered in 1503 by Amerigo Vespucci
DUNCE Basic Facts • 50 kpc distant in the constellation Dorado • Tidal radius 15 ± 4.5 kpc (van der Marel et al. 2002, ApJ 124, 2639) • Actual distance is not known (despite supernova studies) because the LMC is thick. • Actual distance is not known (despite supernova studies) because the LMC has depth. Wei-Hao Wang (IfA, U. Hawaii)
Basic Facts • Third closest galaxy to the Milky Way (thus discovered)
Basic Facts • Fourth most massive galaxy in the Local Group Harwit, M. “Astrophysical Concepts”. 3rd ed. Springer-Verlag 1998
Things we can do with the LMC • Calibrate Distance scales (Hubble 1925, Obs, 48, 139H ) • Find the age of the universe • Study stellar evolution from a top down perspective • Find Dark Matter between the LMC and us (microlensing) • Constrain the size of the Milky Way dark halo • Study supernova evolution • Study ISM from a top down perspective • Give seminar presentations • Develop galaxy formation models • Develop galactic chemical evolution models • Find more massive and rare stars
Morphology • Often considered irregular • Prototype SBm barred Magellanic Type spiral “Mediocre Design”
Morphology • The LMC has globular clusters of its own, in disk-like orbits (reason unknown)
The Brothers Magellanic The Large and Small Magellanic Clouds are interacting with each other (but not actually bound to each other). The Magellanic stream contains 630×106 Msun of gas. (Brüns et al. 2005 A&A, 432, 45) The Parkes HI telescope Brüns et al. 2005 (A&A, 432, 45)
The Eventual Fate of the LMC • Slowly spiraling into Milky Way • According to Mastropietro et al. (2005, MNRAS 363, 509) the LMC has lost its dark matter halo already • Has lost large quantities of gas Mastropietro et al. 2005, MNRAS 363, 509
The Eventual fate of the LMC • Mastropietro et al. assume the LMC started as a small spiral galaxy • ‘Arms’ form naturally from the tidal forces and gas/halo ram pressure
The Eventual Fate of the LMC • Final state of the simulation results in a ring of matter around the Milky Way • Simulation intentionally ignores SMC • Simulation ignores the potential collision with Andromeda 3-4 Gyr from now
400 Ly ×600 Ly Stars: Those pretty pointy things • Despite tidal and gravitational forces, the LMC has plenty of gas • Was a ‘dark galaxy’ until relatively recently- few if any clusters between 4 and 10 Gyr old (van den Bergh 2000 PASP 112, 529) DEM L 130a (LMC N119) (NGC 1910) An honest-to-goodness spiral nebula SuperCOSMOS Red plate
OB associations in the LMC • Difficult to date • The LMC is uniformly low metallicity, so Pop I and Pop II are irrelevant The SN1987a OB association Blue= >6Msun, Green=2-6Msun, Red=<2Msun http://heritage.stsci.edu/1999/04/nino/nino_ctr.html
30 Doradus (Tarantula Nebula) 280 parsecs 9 parsecs Orion Nebula (M42) NASA,ESA, M. Robberto (Space Telescope Science Institute/ESA)
R136 30 Doradus: King of the Star Forming Regions HST, John Trauger (JPL), James Westphal (Caltech), Nolan Walborn (STScl), Rodolfo Barba' (La Plata Observatory), NASA
How we can see Superbubbles • Holes in HI, shells of HII (fainter as you go outward) • Purple is Hα, Cyan is OIII. 350 ly Superbubble N44 Gemini Observatory GMOS Image/Travis Rector - University of Alaska Anchorage
SN 1987a (1997) Hubble Heritage Team (AURA/STScI/NASA/ESA) SN 1987a (2006) NASA, ESA, P. Challis & R. Kirshner (Harvard-Smithsonian Center for Astrophysics)