ModernModern observationalobservational astronomy:astronomy: fromfrom starsstars toto galaxiesgalaxies Martes Martes Miercoles Jueves Viernes MartesMartes MiercolesJueves I – Overview on modern telescopes & Observation techniques II – Some history of galactic astronomy III – Astronomical measurements IV – Properties of stars V – Star clusters & Stellar populations VI – Milky Way & Local Group VII – Disk galaxies & Group environment VIII – Ellipticals & Galaxy Clusters IX – Galaxy evolution in different environments X – Large scale galaxy distribution & Observational cosmology Dr. Michael Hilker (Sternwarte Bonn) ModernModern observationalobservational astronomy:astronomy: fromfrom starsstars toto galaxiesgalaxies Universidad Nacional de Colombia, Bogota, Agosto 2005 I – Overview on modern telescopes and observation techniques Dr. Michael Hilker (Sternwarte Bonn) InIn thethe EinsteinEinstein year:year: DidDid AlbertAlbert EinsteinEinstein hadhad observingobserving experience?experience? ProbablyProbably not.not. ButBut forfor sure,sure, hehe waswas interestedinterested inin anyany observationalobservational resultresult atat thatthat time…time… ...... andand alsoalso visitedvisited observatories!observatories! Dr. Michael Hilker (Sternwarte Bonn) AlbertAlbert EinsteinEinstein visitingvisiting observatoriesobservatories on solar tower (Mount Wilson 1930) At Yerkes Observatory (1930) Dr. Michael Hilker (Sternwarte Bonn) Galileo’sGalileo’s telescopetelescope (1609)(1609) Newton’sNewton’s telescopetelescope (1671)(1671) Dr. Michael Hilker (Sternwarte Bonn) TheThe telescopestelescopes ofof Hevelius:Hevelius: smallsmall …… largelarge …… hugehuge …… ca.1673ca.1673 ca.1647ca.1647 Dr. Michael Hilker (Sternwarte Bonn) RefractorRefractor ReflectorReflector For a given focal length f, the tube of a refracting telescope has to be much longer than that of a reflecting telescope. Today, focal reducers allow even shorter telescope support structures. Dr. Michael Hilker (Sternwarte Bonn) Observatory 350 years ago … … and today Dr. Michael Hilker (Sternwarte Bonn) Chile, Atacama desert: the Very Large Telescope (VLT): 4 single telescopes with mirrors of 8.2m diameter Dr. Michael Hilker (Sternwarte Bonn) Chile, Atacama desert: the Very Large Telescope (VLT): transportation of mirrors Dr. Michael Hilker (Sternwarte Bonn) Chile, Atacama desert: the Very Large Telescope (VLT): polished 8.2m mirror Dr. Michael Hilker (Sternwarte Bonn) One of the Unit Telescopes (UT) at „El Paranal“ (VLT) Dr. Michael Hilker (Sternwarte Bonn) Observing at the beginning of the last century (Edwin Hubble) … … and today Dr. Michael Hilker (Sternwarte Bonn) „Residencia“ of the Very Large Telescopes Dr. Michael Hilker (Sternwarte Bonn) Mauna Kea, Hawaii Las Campanas, Chile telescope control room Dr. Michael Hilker (Sternwarte Bonn) Dr. Michael Hilker (Sternwarte Bonn) The Effelsberg 100-meter radio telescope QuickTimeﾪ and a YUV420 codec decompressor are needed to see this picture. Dr. Michael Hilker (Sternwarte Bonn) RecentRecent developmentsdevelopments Always the progress in astronomy has been dictated by the advances in technology. Some of the advanced astronomical instrumentations and techniques and their implications for galactic astronomy are listed here. Detectors: • charge coupled devices (CCDs) allows to study very faint phenomena, like very distant galaxies and outermost part of galaxies • infrared detector arrays study galaxies in the near infrared where the absorbing effects of dust are small • integral field units (IFUs) makes two-dimensional spectroscopy with high resolution possible, i.e. for dynamics in cores of galaxies Telescope technology: • bigger telescopes, 8 -10m in diameter (Keck, VLT) going to fainter limits • interferometry with radio and optical telescopes improving the resolution • active optics - corrects the mirror deformations improving the PSF • adaptive optics - corrects the atmosphere’s distortions in real time reaching the diffraction limit - resolves very small structures Dr. Michael Hilker (Sternwarte Bonn) Dr. Michael Hilker (Sternwarte Bonn) Astronomical satellites: • HST - largest optical telescope in space dark sky, diffraction limited, probes galaxies at high redshifts and details in nearby galaxies • astrometry (Hipparcos, GAIA, SIM) measures accurate stellar positions structure of our Galaxy, absolute calibration of distance scale • X-ray (Einstein, ROSAT, Chandra, XMM) detects the hot gas in ellipticals and galaxy clusters, active galactic nuclei • infrared (COBE, Spitzer) looks through dust (near-IR), maps the dust distribution in galaxies (far-IR) Computer technology: • fast processors automatic data reduction pipelines, support modern observing technology • storage capacity handling of large quantities of data, availability of large database of galactic astronomy (images, parameters) • parallel processors modelling of galaxy formation and evolution with higher and higher resolution (+ GRAPE processors) Prominent surveys: Sloan Digital Sky Survey (SDSS), 2MASS, 2dF Survey, SAURON, Macho Project, etc. Dr. Michael Hilker (Sternwarte Bonn) The “astronomical” window Many wavelength regimes can only be seen from space Dr. Michael Hilker (Sternwarte Bonn) The electromagnetic spectrum What do we measure in different wavelengths? Radio: atomic, molecular and ionized gas, hydrogen, (stars) Microwave: dense gas, molecules The shorterInfrared: the interstellar wavelength… dust, star formation old, cold stars Visible: stars, blue: young, metal-poor … the hotter the red: material!old, metal-rich … the moreUltraviolet: energetic young, hot the stars process! X-ray: hot gas in and between galaxies, double stars, SN remnants Gamma: highly accelerated particles, accretion onto black holes Dr. Michael Hilker (Sternwarte Bonn) The Milky Way as seen in different wavelength regimes Dr. Michael Hilker (Sternwarte Bonn) Astronomical observations at different wavelengths Spitzer Space Telescope Hubble Space Telescope Chandra X-ray observatory (infrared) (optical) (X-ray) Keck Telescope (Hawaii) VLT (Chile) Very Large Array (USA) (optical, IR, UV) (optical, IR, UV) (Radio) Dr. Michael Hilker (Sternwarte Bonn) Observations from Earth versus Observations from Space - Resolving into fainter details White dwarfs in M4 Dr. Michael Hilker (Sternwarte Bonn) Observation of the famous Hubble Deep Field QuickTimeﾪ and a YUV420 codec decompressor are needed to see this picture. Dr. Michael Hilker (Sternwarte Bonn) Space based observing at various wavelengths SN 1987A after 15 years (optical with HST) Jet of elliptical M87 (X-ray/radio/optical) Trifid nebula (infrared with Spitzer Space Telescope) Dr. Michael Hilker (Sternwarte Bonn) The nearest elliptical galaxy: Centaurus A Dr. Michael Hilker (Sternwarte Bonn) Centaurus A at various wavelengths Dr. Michael Hilker (Sternwarte Bonn) HI in the merger remnant Centaurus A Dr. Michael Hilker (Sternwarte Bonn) X-ray in Stephan´s Quintet Dr. Michael Hilker (Sternwarte Bonn) SomeSome modernmodern instruments:instruments: • FOcal Reducer/low dispersion Spectrograph (FORS) optical imaging and low resolution spectroscopy • Wide Field Imager (WFI) optical wide-field imaging • Infrared Spectrometer And Array Camera (ISAAC) infrared imaging and spectroscopy • Ultraviolet and Visual Echelle Spectrograph (UVES) high resolution spectroscopy • Fibre Large Array Multi Element Spectrograph (FLAMES) low and high resolution multi-object spectroscopy + IFUs • 2dF spectrograph (2 degree field) wide-field multi-object spectroscopy • Very Large Telescope Interferometer (VLTI) high spatial resolution imaging Dr. Michael Hilker (Sternwarte Bonn) Dr. Michael Hilker (Sternwarte Bonn) FOcal Reducer/low Dispersion Spectrograph (FORS) FORS1 CCD chip FORS optical layout Dr. Michael Hilker (Sternwarte Bonn) Wide Field Imager (WFI) at 2.2m tele- scope at La Silla 8k x 8k CCD array, field-of-view: 34’x33’ blue red quantum efficiency of CCDs Dr. Michael Hilker (Sternwarte Bonn) Infrared Spectrometer And Array Camera (ISAAC) ISAAC optical layout Dr. Michael Hilker (Sternwarte Bonn) Fibre Large Array Multi Element Spectrograph (FLAMES) MEDUSA fibre setup The fibre positioner OzPoz and GIRAFFE spectrograph Dr. Michael Hilker (Sternwarte Bonn) Ultraviolet and Visual Echelle Spectrograph (UVES) GIRAFFE spectrograph Dr. Michael Hilker (Sternwarte Bonn) The Anglo-Australian Observatory Dr. Michael Hilker (Sternwarte Bonn) The AAO 2 Degree Field Spectrograph Dr. Michael Hilker (Sternwarte Bonn) 400 Optical Fibres: ‘Byzantine tangles’ 1. Configuration software 4. Results: 400 spectra on 2 CCDs 2. Fibre positioning by robot 3. Completed field plate Dr. Michael Hilker (Sternwarte Bonn) One of the largest redshift surveys Dr. Michael Hilker (Sternwarte Bonn) Dr. Michael Hilker (Sternwarte Bonn) The layout of SAURON field of view: 41” x 33”, resolution: 0.”94 x 0.”94 Dr. Michael Hilker (Sternwarte Bonn) SAURON stellar velocity field showing NGC 4365 a kinematically reconstructed decoupled core surface bright- ness image and slowly varying position and stellar velo- in outer parts city field showing a kinematically decoupled core triaxiality velocity disper- sion map Mg b map Hβ map Dr. Michael Hilker (Sternwarte Bonn) Very Large Telescope Interferometer (VLTI) VLT Interferometer principle separation/resolution ~ λ/D D: distance between mirrors Interferometric tunnel Dr. Michael Hilker (Sternwarte Bonn) SelectedSelected futurefuture developments:developments: • Atacama Large Millimeter Array (ALMA) high spatial resolution submillimeter ‘imaging’ and spectroscopy