STAR CLUSTERS Lecture 1 Introduction Nora Lützgendorf (ESA)
I ts 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
O utline 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
O utline 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
C urrent Position JWST/NIRSpec Instrument and Calibration Scientist Nora Lützgendorf, KAS16 5 / 49
E uropean S pace A gency space science hum an spaceflight launchers exploration operations navigation earth observation telecom m unications technology Nora Lützgendorf, KAS16 6 / 49
J ames W ebb S pace T elescope FACTS WHAT: Infrared space telescope WHERE: Lagrange Point 2 WHEN: October 2018 MIRROR: 6.5 m Nora Lützgendorf, KAS16 7 / 49
J ames W ebb S pace T elescope Nora Lützgendorf, KAS16 8 / 49
J ames W ebb S pace T elescope Nora Lützgendorf, KAS16 8 / 49
C urrent Position OBSERVATORY SEGMENT LAUNCH SEGMENT GROUND SEGMENT Payload Spacecraft adapter (bus, sunshield…) Launcher (Ariane 5) Telescope Launch site services Payload module (ISIM) and instruments Science and operation center (STScI) NIRCam NIRSpec 15 ESA staff members MIRI FGS/NIRISS Common systems (deep space network) Provided by ESA Provided by CSA Provided by NASA Nora Lützgendorf, KAS16 9 / 49
N IRSpec Fixed Slit Spectroscopy Multi Object Spectroscopy Integral Field Spectroscopy Nora Lützgendorf, KAS16 10 / 49
T asks BEFORE LAUNCH (2018) AFTER LAUNCH • 80% duties, 20% science • 50% duties, 50% science • assist in calibration campaigns • commissioning (final calibration and science (like Cryo Vacuum Tests at NASA) verification of the instrument) • reduce and analyze data from these • user support (help astronomers to observe campaigns with the instrument) • create calibration files for the instruments (flat- • calibration monitoring (degrading of fields, darks, …) hardware, change in instrument…) • assist in GTO observation preparations • … Making sure astronomers use the Making sure the instrument is usable for instrument most efficiently doing Astronomy Nora Lützgendorf, KAS16 11 / 49
H ow 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, KAS16 Nora Lützgendorf, KAS16 12 / 49 / 49
O utline 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
I ntroduction “The Milky Way is nothing else but a mass of innumerable stars planted together in clusters” - Galileo Galilei (1610) Nora Lützgendorf, KAS16 14 / 49
I ntroduction “Most stars form in clusters” - Lada & Lada (2003) Nora Lützgendorf, KAS16 15 / 49
S tar Cluster Collection of stars roughly born at the same time Collection of stars that are gravitationally bound Nora Lützgendorf, KAS16 16 / 49
Excursion: Color-magnitude diagram L/M V L/M HOT COLD T/(V-I) Nora Lützgendorf, KAS16 17 / 49
C olor-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 H+He 3) Horizontal 2) Red Giant Branch Star L/M V L/M C+O H+He He H+He 1) Main Sequence 4) Asymptotic Star Giant C+O HOT COLD T/(V-I) 5) White Dwarf Nora Lützgendorf, KAS16 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
T ypes of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 1e5-1e7 1e6-1e8 OB Embedded Open Globular Nuclear Associations Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 21 / 49
E nvironment Nuclear Clusters Open OB Clusters Associations Embedded Clusters Globular Clusters Nora Lützgendorf, KAS16 22 / 49
T ypes of clusters N stars 100 -1000 1e4-1e6 1e4-1e5 1e5-1e7 1e6-1e8 OB Embedded Open Globular Nuclear Association Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 23 / 49
O B Associations SMC - NGC 346 - 20 - 500 pc 300 pc - 0.1 stars/pc - gravitationally unbound M33 - NGC 604 - 12 within 650 pc 70 pc Nora Lützgendorf, KAS16 24 / 49
S tar Cluster Collection of stars roughly born at the same time Collection of stars that are gravitationally bound Nora Lützgendorf, KAS16 25 / 49
T ypes of clusters N stars 1e4-1e6 100 -1000 1e4-1e5 1e5-1e7 1e6-1e8 OB Embedded Open Globular Nuclear Associations Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 26 / 49
E mbedded clusters - 1 - 10 pc - 100 - 1000 stars/pc 3 - age < 5 Myr - may or may not be bound - still gas in / around the cluster ➡ High extinction 4 3 2 J-H 1 0 1 1 0 1 2 3 4 H-K Nora Lützgendorf, KAS16 27 / 49
E mbedded clusters Video can be found here: https://www.youtube.com/watch?v=JcqlTOrijtk Nora Lützgendorf, KAS16 Nora Lützgendorf, KAS16 28 / 43 / 49
T ypes of clusters N stars 1e4-1e5 100 -1000 1e4-1e6 1e5-1e7 1e6-1e8 OB Embedded Open Globular Nuclear Associations Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 29 / 49
O pen clusters - core radii ~ 2pc - mass ~ 100 - 1000 M SUN - age: between 3 Myr and a few Gyr - no gas left NGC 3603 - gravitationally bound NGC 4755 NGC 3766 Arches Nora Lützgendorf, KAS16 30 / 49
O pen clusters - Observations - ~ 2000 identified ➡ 1e5 within the Galaxy! (extinction) Globular Clusters Open Clusters Nora Lützgendorf, KAS16 31 / 49
T ypes of clusters N stars 1e5-1e7 100 -1000 1e4-1e6 1e4-1e5 1e6-1e8 OB Embedded Open Globular Nuclear Associations Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 32 / 49
G lobular Clusters - 1-30 pc - mass ~ 10 4 - 10 6 M SUN - gravitationally bound - age: 10 - 12 Gyr ➡ oldest objects in the universe! Nora Lützgendorf, KAS16 33 / 49
G lobular Clusters - 1-30 pc - mass ~ 10 4 - 10 6 M SUN - gravitationally bound - age: 10 - 12 Gyr ➡ oldest objects in the universe! Nora Lützgendorf, KAS16 33 / 49
G lobular Clusters - Are dense DENSITY ~10 3 1/pc 3 SUN ALPHA CENTAURI Nora Lützgendorf, KAS16 34 / 49
G lobular Clusters - Not what expected PAST: - All stars formed at the same time - All stars have the same chemical composition TODAY: (see Lecture 2) Omega Centauri, Bellini et al., 2011 Nora Lützgendorf, KAS16 35 / 49
G lobular Clusters - Live in Galaxies Always around galaxies Milky Way Andromeda M87 ~200 GCs ~500 GCs ~15 000 GCs Nora Lützgendorf, KAS16 36 / 49
G lobular Clusters - Specific Frequency Number of Globular Clusters in a galaxy divided by the galaxy’s luminosity: S N = N GC /L G - 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
G lobular 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
Y oung Massive Clusters - Young cluster populations forming today - Maybe forming Globular Clusters??? - Formation Environments: Galaxy Mergers Spiral Galaxies Starbursting Dwarfs High Star Formation Nora Lützgendorf, KAS16 39 / 49
T ypes of clusters N stars 1e6-1e8 100 -1000 1e4-1e6 1e4-1e5 1e5-1e7 OB Embedded Open Globular Nuclear Associations Clusters Clusters Clusters Clusters Nora Lützgendorf, KAS16 40 / 49
N uclear Clusters - 1-30 pc - mass ~ 10 5 - 10 8 M SUN - 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 41 / 49
N uclear Clusters - Are super dense DENSITY ~10 6 1/pc 3 DENSITY ~10 6 1/pc 3 SUN ALPHA CENTAURI ALPHA CENTAURI Nora Lützgendorf, KAS16 42 / 49
N uclear Clusters - Host black holes NGC 404 Seth et al., 2010 Nora Lützgendorf, KAS16 43 / 49
N uclear Clusters - Formation 1.) Globular Cluster infall 2.) Gas accretion, star formation Nora Lützgendorf, KAS16 44 / 49
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