(some) 21st Century Experiments in Cosmology Mário Santos (CENTRA – IST) PASC Winter School - Sesimbra 2007

Decision makers… Europe: –ESFRI (European Strategy Forum on Research Infrastructures) – European Roadmap for the next years –Astronet (national resarch organizations + ESA + ESO) – Strategic plan for European Astronomy (Science Vision / Infrastructure Roadmap) –ESO (European Southern Observatory) / ESA (European Space Agency) – ESA Cosmic Vision, US: –NASA (Beyond Einstein Program) –National Academies / National Research Council / Board on Physics and Astronomy: Astronomy and Astrophysics Decadal Survey (2010)

Astronet Infrastructure Road Map PANEL A - High energy, astro-particle astrophysics and gravitational waves AGILE AMS Argos-X Auger North Cherenkov Telescope Array Einstein Gravitational Wave Telescope GLAST IceCube INTEGRAL Km3Net LIGO/Advanced LIGO LISA Spektr-RG SVOM Swift Simbol-X VIRGO/Advanced VIRGO XMM-Newton ESA Cosmic Vision Statements of Interest EDGE GRIPS - GRB Investigations via Polarimetry and Spectroscopy Space Observatory for the study of the Universe at Ultra High Energies The Gamma-Ray Imager Mission XEUS

Infrastructure Astronet Infrastructure Road Map PANEL B - UVOIR and radio/mm, including survey instruments ALMA APEX CCAT E-ELT e-MERLIN European VLBI Network GAIA Gemini GranTeCan IRAM JWST KOI LBT LOFAR LSST Plan for multiplexed spectrograph on 8-10m class telescopes Prospects of Antarctica for UV/optical/IR/radio astronomy Sardinia Radio Telescope SKA Stellar Imager Concept The Modern Universe Space Telescope VLT/VLT instruments VLTI World Space Observatory ESA Cosmic Vision Statements of Interest –A New Window to the Universe: Very Low Frequency Astrophysics (VLFA) –B-Pol –Darwin –DUNE: The Dark Universe Explorer –Enabling science for DARWIN. PEGASE : a space interferometer to study stellar environments and low mass objects –Far Ultraviolet Space Observatory –FIRI - the Far-InfraRed Interferometer –Fresnel Interferometric Imager –Luciola –Measurement of cosmological magnetic fields in Lyman-alpha clouds through the paramagnetic Faraday effect –Millimetron –PLATO - PLAnetary Transits and Oscillations of stars –SPACE : the SPectroscopic All-sky Cosmic Explorer –SPICA: The next generation IR space observatory –Stellar and Galactic Environment Survey (SAGE) –Super-Earth Explorer SEE-COAST –The Celestial Exoplanet Survey Occulter –The Molecular Hydrogen Explorer (H2EX)

Planck Satellite to measure the Cosmic Microwave Background radiation (Intensity and Polarization) Constraints on: dark matter, dark energy, reionization, neutrino mass, Inflation… Launch: 31st July 2008 COBE (  K) Planck (  K)

CMB Inflation Probes Aim: to measure the full sky B-mode polarization and detect the primordial gravitational waves generated during Inflation Launch? B-POL (ESA) EPIC – Einstein Polarization Interferometer for Cosmology (NASA) CMB Pol (NASA) B-POL B-mode polarization measurements

Dark Energy Missions Dune - the Dark Universe Explorer (ESA) –Constrain the dark energy equation of state and provide a dark matter map of the Universe through the measurement of the gravitational weak lensing effect (from the galaxy shear)

Dark energy missions SPACE (ESA) - Spectroscopic All-sky Cosmic Explorer –Full 3-d galaxy map with high precision spectroscopy – Baryon acoustic oscillations and dark energy constraints SNAP (NASA) – Supernova Acceleration Probe –SNIa measurements + weak lensing Destiny (NASA) ADEPT (NASA) Launch: 2017/2018 ? NASA's Beyond Einstein Program (Sept. 2007)

LISA (Laser Interferometer Space Antenna) Direct detection of gravitational waves: –Binaries (black holes, neutron stars, etc) in the Milky Way –Massive black hole mergers from other galaxies –Primordial gravitational waves –Low frequencies (< 1 Hz) –Lauch: 2020? (NASA/ESA)

JWST (James Webb Space Telescope) Hubble Space Telescope successor NASA / ESA / CSA Launch: 2013 Large Infrared telescope – 6.5 m diameter Science: –The end of the dark ages (Reionization) –Galaxy assembly –The birth of stars –Planets and origin of life

LSST (The Large Synoptic Survey Telescope) Cosmic Cartography: –Aperture: 8.4 m –10 square degrees snapshots every 15s –Total available sky in 3 nights –FoV: degrees 2 –Full movie over 5 years –Camera: 3 Gpixels –First light: 2015 Science: –Over 10 9 galaxies –10 6 SNIa –Dark energy constraints from weak lensing and baryon acoustic oscillations –Near earth objects detection

The new “digital telescopes” Large radio interferometers (many simple antennas)Large radio interferometers (many simple antennas) Signal digitized – combined in computers to emulate large collecting areaSignal digitized – combined in computers to emulate large collecting area Large collecting area and high resolution at. 200 MHz ) Good to probe the high redshift Universe (z>6) through the 21cm lineLarge collecting area and high resolution at. 200 MHz ) Good to probe the high redshift Universe (z>6) through the 21cm line

LOFAR (Low Frequency Array) 30 MHz < < 240 MHz30 MHz < < 240 MHz antennas15000 antennas Spread over 100 Km in diameterSpread over 100 Km in diameter End of 2008: 20 stations (100 antennas each)End of 2008: 20 stations (100 antennas each) Note:Note: –FOV / 2 /d 2 (d – antenna “size”) (d – antenna “size”) –Resolution / D/ –Resolution / D/ (D – maximum separation) (D – maximum separation)

SKA (Square Kilometre Array) “A radio telescope with an effective collecting area more than 30 times greater than the largest telescope ever built will reveal the dawn of galaxy formation, as well as many other new discoveries in all fields of astronomy” ESFRI Roadmap – 2006 report

SKA: Specs Several x 10 6 m 2 total collecting area 100 MHz < < 10 GHz Baselines up to 3000 Km Beginning of operation: 2015 Full operation: 2020 At z=8 (158 MHz): –FOV ~ 200 deg 2 –   ~ 1.3’ (5 Km) –  ~ 2  Jy –  T ~ 15 mK

SKADS (SKA Design Studies) International collaboration: establish experimental design and technologies used for SKAInternational collaboration: establish experimental design and technologies used for SKA CENTRA – IST joined recently the SKADS consortium: participant in the DS2 design studies (Science and Astronomical Data Simulations)CENTRA – IST joined recently the SKADS consortium: participant in the DS2 design studies (Science and Astronomical Data Simulations) Key Science projects:Key Science projects: –Probing the dark ages (Reionization) –Galaxy evolution, cosmology and dark energy –Strong field tests of gravity using pulsars and black holes –The origin and evolution of Cosmic Magnetism –Cradle of Life

Reionization Z=7.4 Z=10.0 Z=15.2 Today ~ 99% of H is ionized Process: star formation and subsequent ionization of the IGM Complex history: 6 < z <17 (500 million years) Simulation: 100 Mpc/h side, (720)3 cells, ~ 24 billion particles

21cm radiation Use hyperfine transition line in hydrogen atoms: 1S 1/ MHz (21 cm) n=1, l =0, F=0 n=1, l =0, F=1 HI cloud CMB Final intensity No need for bright sources (seen against the CMB) Probe directly the neutral hydrogen distribution in the Universe and the Epoch of Reionization

The 21cm signal 1420 MHz line - 90 MHz < < 200 MHz for 6 < z < MHz line - 90 MHz < < 200 MHz for 6 < z < 15 Need radio interferometers - 21cm experiments!Need radio interferometers - 21cm experiments! The ionization fraction Corresponding 21cm signal (brightness temperature)

Making 3-d maps with SKA Tomographic view of the Universe between z=19 and z=6 Sensitive to: ionization, dark matter, IGM gas temperature, Lyman alpha background… Santos et al arXiv:

21cm signal: Statistics 3d Power Spectrum: –Simulation (thin curves) versus analytical model (thick curves) –From bottom to top: z=7.4, 10.0, 15.2, 20.6 z=9.2 =140MHz P-S 21cm Extragal. f-f CMB Galat. f-f Synch. Huge foreground contribution - doable? Yes! (see M. Santos et al, Astrophys.J. 625 (2005), 575 and Wang et al, Astrophys.J. 650 (2006) 529)

Cosmological and Astrophysical parameter Constraints X H – neutral fraction, R x H – bubble size Frequency range: 135MHz – 167 MHz (7.5 < z <9.5) Marginalized over foregrounds M. Santos and A. Cooray, Phys.Rev. D74 (2006)

Conclusions Interested in Cosmology? –Keep an eye on *at least* the following experiments: Planck, B-POL, DUNE, SNAP, LISA, JWST, LSST, SKA