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Breathing in, I calm myself This is a wonderful moment Breathing out, I smile Living in the present moment --Thick Nhat Hanh Slide 2 SOAR 2014: Galaxies Aileen A. ODonoghue Priest Associate Professor of Physics Slide 3 Galaxies 9/9/14 Milky Way Galaxy Contents & Motions 9/16/14 Milky Way Environment & the Local Group 9/23/14 Other Galaxies & Clusters of Galaxies 9/30/14 Expansion, History & Evolution of the Universe 9/9/14 Milky Way Galaxy Contents & Motions 9/16/14 Milky Way Environment & the Local Group 9/23/14 Other Galaxies & Clusters of Galaxies 9/30/14 Expansion, History & Evolution of the Universe Slide 4 SOAR: Galaxies The Milky Way Environment & the Local Group Aileen A. ODonoghue Priest Associate Professor of Physics Slide 5 The Local Group The Milky Ways Galaxy Cluster > 54 galaxies within 5 million light years Andromeda (M31) & Satellites M32 & M33 Triangulum (M110) Milky Way Slide 6 The Hood Slide 7 Milky Ways Environment IntraCluster Medium (ICM) Did galaxies form from this gas? IntraCluster Medium (ICM) Did galaxies form from this gas? Slide 8 Milky Ways Environment Galaxies emit and absorb gas Slide 9 Milky Ways Environment Milky Ways Lumpy Halo Stars, Globular Clusters, Gas, Dwarf Galaxies Milky Ways Lumpy Halo Stars, Globular Clusters, Gas, Dwarf Galaxies Being studied by RA dial V elocity E xperiment by Institutions from 11 nations Slide 10 Galactic Cannibalism Galaxies grow by eating their neighbors MW has 9 dwarf companion galaxies Halo stars from disrupted dwarfs Galaxies grow by eating their neighbors MW has 9 dwarf companion galaxies Halo stars from disrupted dwarfs Slide 11 The Milky Way Growing? Galaxies merge with other galaxies Galactic Cannibalism Milky Way has two known merging galaxies Dwarf Elliptical Galaxy in Sagittarius Dwarf Galaxy in Canis Minor Closest galaxy in process of merging Researchers expect to find more! Galaxies merge with other galaxies Galactic Cannibalism Milky Way has two known merging galaxies Dwarf Elliptical Galaxy in Sagittarius Dwarf Galaxy in Canis Minor Closest galaxy in process of merging Researchers expect to find more! Slide 12 Sagittarius Dwarf Elliptical Part of the Sagittarius Stream of gas & stars 52 klyc from galactic center Has passed through MW 10 times Dark Matter indicted by lack of disrupton! Part of the Sagittarius Stream of gas & stars 52 klyc from galactic center Has passed through MW 10 times Dark Matter indicted by lack of disrupton! Stars of SgrDEG have different speeds than MW stars SgrDEG on far side of galactic center Slide 13 Sagittarius Stream Stars & gas stripped from SgrDEG Flyaround of Milky Way with Sagittarius Stream APODAPOD image of Sagittarius Stream Slide 14 Sagittarius Stream Simulations of tidal stripping of SgrDEG ~ 2 billion BCE to 500 million CE Simulations of tidal stripping of SgrDEG ~ 2 billion BCE to 500 million CE Color indicates time of tidal stripping Color indicates stellar density Simulations by Kathryn V. Johnston, Wesleyan UniversityKathryn V. Johnston Slide 15 Canis Minor Dwarf Discovered in 2003, 25 kly from MW center Slide 16 CMi Dwarf Discovered in 2003 42 kly from MW center Merging with MW Discovered in 2003 42 kly from MW center Merging with MW Slide 17 Milky Way Ring Thick ring of stars beyond disk Slide 18 Milky Way Ring Due to past galactic collision? Which of these galaxies passed through one to left? Star formation in ring of shocked gas Slide 19 The Local Group More than 54 galaxies Mostly dwarfs, including those merging with the Milky Way 3 Major spiral galaxies Milky Way, Andromeda & Triangulum More than 54 galaxies Mostly dwarfs, including those merging with the Milky Way 3 Major spiral galaxies Milky Way, Andromeda & Triangulum http://www.atlasoftheuniverse.com/ Slide 20 Polaris Pointer stars point to Alpheratz Scheat Almach L ITTLE D IPPER B IG D IPPER C EPHEUS C ASSIOPEIA Algenib Markab Rasalmothallah Capella Algol Cephei A NDROMEDA P EGASUS Enif The Sky Tonight Andromeda Galaxy Triangulum Galaxy T RIANGULUM A RIES Great Square of Pegasus P ERSEUS Slide 21 Alpheratz Almach Rasalmothallah A NDROMEDA Finding Galaxies Andromeda Galaxy Triangulum Galaxy T RIANGULUM Slide 22 Andromeda Galaxy Local Groups Largest Galaxy One Trillion Stars (10 12 ) 2.5 million light-years away 1.5 x 10 19 mi (1 ly = 5.88 x10 12 miles ~ 6 trillioin) 200,000,000 M black hole in center Approaching us at 300 km/s (190 miles/sec) Should collide with Milky Way in ~4 billion years Local Groups Largest Galaxy One Trillion Stars (10 12 ) 2.5 million light-years away 1.5 x 10 19 mi (1 ly = 5.88 x10 12 miles ~ 6 trillioin) 200,000,000 M black hole in center Approaching us at 300 km/s (190 miles/sec) Should collide with Milky Way in ~4 billion years Slide 23 M110 Dwarf Galaxy M32 Dwarf Galaxy Slide 24 Triangulum Galaxy Pinwheel Galaxy (M 101) 40 Billion Stars (10 10 ) 3 million light-years away 1.5 x 10 19 mi (1 ly = 5.88 x10 12 miles ~ 6 trillioin) Linked to Andromeda by streams of stars and neutral hydrogen interacted with Andromeda 2-8 by ago will have more violent interaction in 2.5 my may participate in collision with MW Pinwheel Galaxy (M 101) 40 Billion Stars (10 10 ) 3 million light-years away 1.5 x 10 19 mi (1 ly = 5.88 x10 12 miles ~ 6 trillioin) Linked to Andromeda by streams of stars and neutral hydrogen interacted with Andromeda 2-8 by ago will have more violent interaction in 2.5 my may participate in collision with MW Slide 25 http://www.nasa.gov/topics/universe/features/molecule-fingerprints.html Slide 26 The Coming Collision http://www.nasa.gov/mission_pages/hubble/science/milky-way-collide.html