Transcript 21st Century Experiments in Cosmology

(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 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 Map
PANEL A - High energy, astro-particle astrophysics and gravitational waves
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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
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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 Infrastructure Road Map
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PANEL B - UVOIR and radio/mm, including survey instruments
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ALMA
APEX
CCAT
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ESA Cosmic Vision Statements of Interest
E-ELT
e-MERLIN
– A New Window to the Universe: Very Low
Frequency Astrophysics (VLFA)
European VLBI Network
– B-Pol
GAIA
– Darwin
Gemini
– DUNE: The Dark Universe Explorer
GranTeCan
– Enabling science for DARWIN. PEGASE : a
IRAM
space interferometer to study stellar
JWST
environments and low mass objects
KOI
– Far Ultraviolet Space Observatory
LBT
– FIRI - the Far-InfraRed Interferometer
LOFAR
– Fresnel Interferometric Imager
– Luciola
LSST
Plan for multiplexed spectrograph on 8-10m class telescopes – Measurement of cosmological magnetic fields in
Lyman-alpha clouds through the paramagnetic
Prospects of Antarctica for UV/optical/IR/radio astronomy
Faraday effect
Sardinia Radio Telescope
– Millimetron
SKA
– PLATO - PLAnetary Transits and Oscillations of
stars
Stellar Imager Concept
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SPACE : the SPectroscopic All-sky Cosmic
The Modern Universe Space Telescope
Explorer
VLT/VLT instruments
– SPICA: The next generation IR space
VLTI
observatory
World Space Observatory
– Stellar and Galactic Environment Survey (SAGE)
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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
• B-POL (ESA)
• EPIC – Einstein Polarization
Interferometer for Cosmology
(NASA)
• CMB Pol (NASA)
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
NASA's Beyond Einstein Program (Sept. 2007)
• SNAP (NASA) – Supernova Acceleration Probe
– SNIa measurements + weak lensing
• Destiny (NASA)
• ADEPT (NASA)
• Launch: 2017/2018 ?
LISA
(Laser Interferometer Space Antenna)
• Direct detection of gravitational waves:
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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: 20000 degrees2
– Full movie over 5 years
• Science:
– Camera: 3 Gpixels
– Over 109 galaxies
– First light: 2015
– 106 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)
• Signal 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 line
LOFAR
(Low Frequency Array)
• 30 MHz <  < 240 MHz
• 15000 antennas
• Spread over 100 Km in
diameter
• End of 2008: 20 stations
(100 antennas each)
• Note:
– FOV / 2/d2
(d – antenna “size”)
– Resolution / D/
(D – maximum separation)
SKA
(Square Kilometre Array)
ESFRI Roadmap – 2006 report
“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”
SKA: 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):
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FOV ~ 200 deg2
  ~ 1.3’ (5 Km)
 ~ 2 Jy
 T ~ 15 mK
SKADS
(SKA Design Studies)
• International 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)
• 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=15.2
Z=10.0
• 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
Z=7.4
21cm radiation
• Use hyperfine transition line in hydrogen atoms:
n=1, l =0, F=1
1S1/2
1420 MHz (21 cm)
n=1, l =0, F=0
• No need for bright sources
(seen against the CMB)
• Probe directly the neutral
hydrogen distribution in the
Universe and the Epoch of
Reionization
CMB
HI cloud
Final
intensity
The 21cm signal
The ionization fraction
Corresponding 21cm signal
(brightness temperature)
• 1420 MHz line - 90 MHz <  < 200 MHz for 6 < z < 15
• Need radio interferometers - 21cm experiments!
Making 3-d maps with SKA
Santos et al arXiv: 0708.2424
• Tomographic view of the Universe
between z=19 and z=6
• Sensitive to: ionization, dark
matter, IGM gas temperature, Lyman
alpha background…
21cm signal: Statistics
Synch.
P-S
Galat. f-f
Extragal. f-f
21cm
CMB
z=9.2
=140MHz
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• Huge foreground contribution - doable?
Yes! (see M. Santos et al, Astrophys.J. 625
(2005), 575 and Wang et al, Astrophys.J.
650 (2006) 529)
3d Power Spectrum:
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Simulation (thin curves)
versus analytical model
(thick curves)
From bottom to top:
z=7.4, 10.0, 15.2, 20.6
Cosmological and Astrophysical
parameter Constraints
M. Santos and A. Cooray, Phys.Rev. D74 (2006) 083517
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XH – neutral fraction, RxH – bubble size
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Frequency range: 135MHz – 167 MHz (7.5 < z <9.5)
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Marginalized over foregrounds
Conclusions
• Interested in Cosmology?
– Keep an eye on *at least* the following experiments:
• Planck, B-POL, DUNE, SNAP, LISA, JWST, LSST, SKA