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STAR CLUSTERS Lecture 1 Introduction Nora Lützgendorf (ESA) Its a school, so… ? ? ? ? ? ? ? ? ? ➡ ASK QUESTIONS!!! ➡ If you don’t understand the content… ➡ If you don’t understand the language… ➡ TAKE NOTES ➡ This is the most text on a slide you will see ;) Nora Lützgendorf, KAS16 2 / 49 Outline 1. Career 2. Introduction a. What is a star cluster? b. What kind of clusters do we know? c. Where do we find them? d. Characteristics Nora Lützgendorf, KAS16 3 / 49 Outline 1. Career 2. Introduction a. What is a star cluster? b. What kind of clusters do we know? c. Where do we find them? d. Characteristics Nora Lützgendorf, KAS16 4 / 49 Current Position JWST/NIRSpec Instrument and Calibration Scientist Nora Lützgendorf, KAS16 5 / 49 European Space Agency space science human spaceflight exploration launchers operations navigation earth observation telecommunications technology Nora Lützgendorf, KAS16 6 / 49 James Webb Space Telescope FACTS WHAT: Infrared space telescope WHERE: Lagrange Point 2 WHEN: October 2018 MIRROR: 6.5 m Nora Lützgendorf, KAS16 7 / 49 James Webb Space Telescope Nora Lützgendorf, KAS16 8 / 49 James Webb Space Telescope Nora Lützgendorf, KAS16 8 / 49 Current Position LAUNCH SEGMENT OBSERVATORY SEGMENT Payload adapter GROUND SEGMENT Spacecraft (bus, sunshield…) Launcher (Ariane 5) Telescope Launch site services Provided by NASA Nora Lützgendorf, KAS16 Payload module (ISIM) and instruments Science and operation center (STScI) NIRCam NIRSpec 15 ESA staff members FGS/NIRISS MIRI Common systems (deep space network) Provided by ESA 9 / 49 Provided by CSA NIRSpec Fixed Slit Spectroscopy Multi Object Spectroscopy Integral Field Spectroscopy Nora Lützgendorf, KAS16 10 / 49 Tasks BEFORE LAUNCH (2018) AFTER LAUNCH • 80% duties, 20% science • 50% duties, 50% science • assist in calibration campaigns (like Cryo Vacuum Tests at NASA) • commissioning (final calibration and science verification of the instrument) • reduce and analyze data from these campaigns • user support (help astronomers to observe with the instrument) • create calibration files for the instruments (flatfields, darks, …) • calibration monitoring (degrading of hardware, change in instrument…) • assist in GTO observation preparations • … Making sure astronomers use the instrument most efficiently Making sure the instrument is usable for doing Astronomy Nora Lützgendorf, KAS16 11 / 49 How did I get here? LEIDEN, NL (2013-2015) LEIPZIG, D (1985-2004) 2013 – 2015: Research Fellow, ESA 1996 – 2004: High-School MUNICH, D (2005-2013) 2005 - 2010: Diplom (Physics), LMU 2010 - 2013: PhD (Astrophysics), LMU/ESO BALTIMORE, US (since 2015) since 2015: JWST Instrument Scientist, ESA Nora Lützgendorf, Lützgendorf, KAS16 KAS16 12 / 49 Outline 1. Career 2. Introduction a. What is a star cluster? b. What kind of clusters do we know? c. Where do we find them? d. Characteristics Nora Lützgendorf, KAS16 13 / 49 Introduction “The Milky Way is nothing else but a mass of innumerable stars planted together in clusters” - Galileo Galilei (1610) Nora Lützgendorf, KAS16 14 / 49 Introduction “Most stars form in clusters” - Lada & Lada (2003) Nora Lützgendorf, KAS16 15 / 49 Star Cluster Collection of stars roughly born at the same time Collection of stars that are gravitationally bound Nora Lützgendorf, KAS16 16 / 49 L/MV Excursion: Color-magnitude diagram HOT COLD T/(V-I) Nora Lützgendorf, KAS16 17 / 49 Color-magnitude diagram Video can be found here: http://hubblesite.org/newscenter/archive/releases/2010/28 Nora Lützgendorf, KAS16 18 / 49 Excursion: Color-magnitude diagram He He H+He 3) Horizontal Branch Star 2) Red Giant L/MV H+He C+O H+He He H+He 1) Main Sequence Star 4) Asymptotic Giant C+O 5) White Dwarf Nora Lützgendorf, KAS16 HOT COLD T/(V-I) 19 / 49 Excursion: Color-magnitude diagram Marcia Rieke Nora Lützgendorf, KAS16 20 / 49 Excursion: Color-magnitude diagram Marcia Rieke Nora Lützgendorf, KAS16 20 / 49 Excursion: Color-magnitude diagram Marcia Rieke Nora Lützgendorf, KAS16 20 / 49 Excursion: Color-magnitude diagram Marcia Rieke Nora Lützgendorf, KAS16 20 / 49 Excursion: Color-magnitude diagram Marcia Rieke Nora Lützgendorf, KAS16 20 / 49 Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 21 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters Environment Open Clusters Nuclear Clusters Embedded Clusters Globular Clusters Nora Lützgendorf, KAS16 22 / 49 OB Associations Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Association Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 23 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters SMC - NGC 346 OB Associations - 20 - 500 pc 300 pc - 0.1 stars/pc M33 - NGC 604 - gravitationally unbound - 12 within 650 pc 70 pc Nora Lützgendorf, KAS16 24 / 49 Star Cluster Collection of stars roughly born at the same time Collection of stars that are gravitationally bound Nora Lützgendorf, KAS16 25 / 49 Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 26 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters Embedded clusters - 1 - 10 pc 100 - 1000 stars/pc3 age < 5 Myr may or may not be bound still gas in / around the cluster ➡ High extinction 4 3 J-H 2 1 0 1 1 0 1 2 H-K Nora Lützgendorf, KAS16 27 / 49 3 4 Embedded clusters Video can be found here: https://www.youtube.com/watch?v=JcqlTOrijtk Nora Lützgendorf, Lützgendorf, KAS16 KAS16 28 / 49 43 Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 29 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters Open clusters - core radii ~ 2pc - mass ~ 100 - 1000 MSUN - age: between 3 Myr and a few Gyr - no gas left NGC 3603 - gravitationally bound NGC 4755 Nora Lützgendorf, KAS16 NGC 3766 30 / 49 Arches Open clusters - Observations - ~ 2000 identified ➡ 1e5 within the Galaxy! (extinction) Globular Clusters Open Clusters Nora Lützgendorf, KAS16 31 / 49 Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 32 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters Globular Clusters - 1-30 pc - mass ~ 104 - 106 MSUN - gravitationally bound - age: 10 - 12 Gyr ➡ oldest objects in the universe! Nora Lützgendorf, KAS16 33 / 49 Globular Clusters - 1-30 pc - mass ~ 104 - 106 MSUN - gravitationally bound - age: 10 - 12 Gyr ➡ oldest objects in the universe! Nora Lützgendorf, KAS16 33 / 49 Globular Clusters - Are dense DENSITY 3 ~10 SUN Nora Lützgendorf, KAS16 34 / 49 3 1/pc ALPHA CENTAURI Globular Clusters - Not what expected PAST: - All stars formed at the same time - All stars have the same chemical composition Nora Lützgendorf, KAS16 Omega Centauri, Bellini et al., 2011 TODAY: (see Lecture 2) 35 / 49 Globular Clusters - Live in Galaxies Always around galaxies Milky Way ~200 GCs Nora Lützgendorf, KAS16 Andromeda ~500 GCs 36 / 49 M87 ~15 000 GCs Globular Clusters - Specific Frequency Number of Globular Clusters in a galaxy divided by the galaxy’s luminosity: SN = NGC /LG - Formation efficiency of Globular Clusters relative to field stars - Depends on galaxy type (higher in ellipticals) Georgiev et al., 2010 Nora Lützgendorf, KAS16 37 / 49 Globular Clusters - Bimodality BLUE RED Blue Globular Clusters • metal-poor • galaxy halo • larger Red Globular Clusters • metal-rich • bulge/disk • smaller Nora Lützgendorf, KAS16 38 / 49 Young Massive Clusters - Young cluster populations forming today - Maybe forming Globular Clusters??? - Formation Environments: Galaxy Mergers Spiral Galaxies High Star Formation Nora Lützgendorf, KAS16 39 / 49 Starbursting Dwarfs Types of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters Nora Lützgendorf, KAS16 40 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters Nuclear Clusters - 1-30 pc - mass ~ 105 - 108 MSUN - age: multiple epochs of star formation - centers of galaxies - gravitational bound - co-existing with black hole Seth et al., 2006 - densest objects in the universe Nora Lützgendorf, KAS16 Fig. 1.—Images in the F814W filter of the nine candidate nuclear clusters. Each image is 200 on a side, an 10 pc. Images have been rotated so that the x-axis lies along the position angle of the major axis of the gal color version of this figure.] 41 / 49 Nuclear Clusters - Are super dense DENSITY 6 ~10 SUN Nora Lützgendorf, KAS16 42 / 49 3 1/pc ALPHA CENTAURI Nuclear Clusters - Host black holes NGC 404 Seth et al., 2010 Nora Lützgendorf, KAS16 43 / 49 Nuclear Clusters - Formation 1.) Globular Cluster infall 2.) Gas accretion, star formation Nora Lützgendorf, KAS16 44 / 49 Nuclear Clusters - Formation 1.) Globular Cluster infall 2.) Gas accretion, star formation Nora Lützgendorf, KAS16 45 / 49 Nuclear Clusters - Multiple populations Sgr/M54 Siegel et al., 2007 Nora Lützgendorf, KAS16 46 / 49 Nuclear Clusters - Peculiar kinematics Nora Lützgendorf, KAS16 47 / 49 Nuclear Clusters - In our Galaxy Nora Lützgendorf, KAS16 48 / 49 Nuclear Clusters - In our Galaxy Nora Lützgendorf, KAS16 48 / 49 Nuclear Clusters - In our Galaxy Nora Lützgendorf, KAS16 48 / 49 Summary 1. Star Clusters: ➡ Collection of stars roughly born at the same time (sometimes gravitationally bound) 100 -1000 1e4-1e6 1e4-1e5 OB Associations Embedded Clusters Open Clusters - in the disk - in the disk - in the disk - gravitationally unbound - still gas left - gravitationally bound Nora Lützgendorf, KAS16 49 / 49 1e5-1e7 Globular Clusters 1e6-1e8 Nuclear Clusters - in the halo/ bulge - at the center of the galaxy - oldest objects in the universe - densest objects in the universe