(some) 21st Century (some) 21st Century Experiments in CosmologyExperiments in Cosmology

Mário Santos

(CENTRA – IST)

PASC Winter School - Sesimbra 2007

Decision makers…Decision makers…

• Europe:– ESFRI (European Strategy Forum on Research Infrastructures)

– European Roadmap for the next 15-20 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, 2015-2025

• US:– NASA (Beyond Einstein Program)– National Academies / National Research Council / Board on

Physics and Astronomy: Astronomy and Astrophysics Decadal Survey (2010)

Astronet Infrastructure Road MapAstronet Infrastructure Road MapPANEL 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

Astronet InfrastructureInfrastructure 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)

PlanckPlanck

• 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 ProbesCMB 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)

LISALISA(Laser Interferometer Space Antenna)(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

LSSTLSST(The Large Synoptic Survey Telescope)(The Large Synoptic Survey Telescope)

• Cosmic Cartography:– Aperture: 8.4 m– 10 square degrees

snapshots every 15s– Total available sky in 3

nights– FoV: 20000 degrees2

– Full movie over 5 years– Camera: 3 Gpixels– First light: 2015

• Science:– Over 109 galaxies– 106 SNIa– Dark energy constraints from weak

lensing and baryon acoustic oscillations– Near earth objects detection

The new “digital telescopes”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 Large collecting area and high resolution at .. 200 MHz 200 MHz )) Good to probe Good to probe

the high redshift Universe (z>6) through the 21cm linethe high redshift Universe (z>6) through the 21cm line

LOFARLOFAR(Low Frequency Array)(Low Frequency Array)

• 30 MHz < 30 MHz < < 240 MHz < 240 MHz• 15000 antennas15000 antennas• Spread over 100 Km in Spread over 100 Km in

diameterdiameter• End of 2008: 20 stations End of 2008: 20 stations

(100 antennas each)(100 antennas each)• Note:Note:

– FOV FOV // 22/d/d22

(d – antenna “size”)(d – antenna “size”)– Resolution Resolution // D/ D/ (D – maximum separation)(D – maximum separation)

SKASKA(Square Kilometre Array)(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: SpecsSKA: Specs

• Several x 106 m2 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 deg2

– ~ 1.3’ (5 Km)– ~ 2 Jy– T ~ 15 mK

SKADSSKADS(SKA Design Studies)(SKA Design Studies)

• International collaboration: establish International collaboration: establish experimental design and technologies used for experimental design and technologies used for SKASKA

• CENTRA – IST joined recently the SKADS CENTRA – IST joined recently the SKADS consortium: participant in the DS2 design consortium: participant in the DS2 design studies (Science and Astronomical Data studies (Science and Astronomical Data Simulations)Simulations)

• Key Science projects:Key Science projects:– Probing the dark ages (Reionization)Probing the dark ages (Reionization)– Galaxy evolution, cosmology and dark energyGalaxy evolution, cosmology and dark energy– Strong field tests of gravity using pulsars and Strong field tests of gravity using pulsars and

black holesblack holes– The origin and evolution of Cosmic MagnetismThe origin and evolution of Cosmic Magnetism– Cradle of LifeCradle of Life

ReionizationReionization

Z=7.4

Z=10.0Z=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:

1S1/2 1420 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 signalThe 21cm signal

• 1420 MHz line - 90 MHz < 1420 MHz line - 90 MHz < < 200 MHz for 6 < z < 15 < 200 MHz for 6 < z < 15

• Need radio interferometers - 21cm experiments!Need radio interferometers - 21cm experiments!

The ionization fractionCorresponding 21cm signal

(brightness temperature)

Making 3-d maps with SKAMaking 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: 0708.2424

21cm signal: Statistics21cm 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 Cosmological and Astrophysical parameter Constraintsparameter Constraints

• XH – neutral fraction, RxH – bubble size

• Frequency range: 135MHz – 167 MHz (7.5 < z <9.5)

• Marginalized over foregrounds

M. Santos and A. Cooray, Phys.Rev. D74 (2006) 083517

Conclusions

• Interested in Cosmology?– Keep an eye on *at least* the following experiments:

• Planck, B-POL, DUNE, SNAP, LISA, JWST, LSST, SKA