Transcript The Transient Radio Sky Astrophysical and Artificial

C.Carilli, AUI Board October 2006
• ISAC-run three year
process: Quantified
‘experiments’ for future large
area cm telescopes
• 50 chapters, 90 authors,
25% theorists
Key Science Projects: (i) Address key questions, (ii) Unique role of
radio, or complementary but critical, (iii) Excites broad community
Cosmic reionization and first light
HI + continuum survey: galaxy evolution and dark energy
Cosmic magnetism: origin and evolution
Strong field tests of GR using pulsars
Cradle of Life: Terrestrial planet
formation + astrobiology + SETI
KSP I: Cosmic magnetism -- Origin, Structure, Evolution
Experiment: All Sky Polarization/Rotation measure survey (σ 
0.1 μJy at 1.4GHz) -- 2e7 RMs, spaced by ~ 90" (vs. 1500 currently)
Currently:
300 local
pulsar RMs
SKA: 2e4
pulsars
2. Nearby galaxies Synchrotron+RMs: test dynamo models
3. Distant radio galaxies: Intercluster magnetic fields
4. Ly-a absorbers: galaxian magnetic field evolution over cosmic time
5. Cosmic web: the magnetized intergalactic medium
KSP II: Galaxy evolution and dark energy
Experiment: All sky HI line + continuum survey -- 1e9
Galaxies in HI out to z=1.5
1e4/deg^2 in HI
to z=0.5 to 1.5
Goal 1: Galaxy evolution – conversion gas to stars
Goal 2: SKA as Dark Energy Machine
DE EoS: w = P/ = -1? Func(z)?
Baryon Oscillations + Weak lensing:
SKA: variance
limited
Evolution of LSS -- ‘standard ruler’
SKA: measure
w(z) to few %
w(z) = w0 + w1 z
KSP III: Study of Cosmic reionization and first light
The last unexplored phase of cosmic evolution (0.1 to 1Gyr after BB)
Experiment: Imaging 3D ‘tomography’ of IGM in HI 21cm line
“Richest of all cosmological data sets”
z=12 (109MHz)
9
7.6
SDSS J1148+5251: Observing first light at radio wavelengths
z=6.42;
t_univ=0.87 Gyr
J1148 VLA: CO 3-2 at
45GHz
50K
Fan +
1”
1e9 M_sun in dust, 1e10 M_sun in mol. gas =>
 Hyper luminous IR galaxy (FIR =1e13 L_sun):
SFR = 1e3 M_sun/yr ?
 Early enrichment of heavy
elements (z_sf > 8)
 Coeval formation of SMBH/galaxy?
 Integration times: hours to
days on HLIRGs
 Dust formation by massive stars?
 Break-down of M- relation at high z?
Complementarity
Mol. Gas,
dust
SKA
AGN, star formation
Low order mol. lines
Stars, ionized gas
KSP IV: Gravity Beyond Einstein
Experiment: 2e4 Galactic pulsars
Strong field GR tests using
pulsar-black hole binaries
Pulsar Timing Array: most
sensitive gravity wave detector
for SMBH binaries
KSP V: Cradle of life
• Terrestrial planet formation: disks
and gaps on sub-AU scales
(complementary with ALMA).
• Prebiotic large molecules (abiotic
amino acids)
• Search for Extraterrestrial
Intelligence: leakage radiation
(interstellar TV)
• All require sensitivity: A/T >= 1e4 m^2/K
• Most require frequencies >= 10 GHz
• Many require > 1deg^2 FoV at 1.4 GHz
• Some require > 1000 km baselines
• A few require multibeaming
END
Pathfinders
Freq (GHz) Year
Focus
0.3 – 50
2012
Broad, thermal
• eMERLIN
1 – 30
2010
High resolution
• ATA
1 – 10
2008?
Wide fields
• DSN
8, 32
2010?
Telemetry
• EVLA I
• LWA
0.03–0.08
2009
Low freq window
• LOFAR
0.08 – 0.3
2009
EoR++
• MWAd
0.1 – 0.3
2009
EoR+
• PAPER
0.1 – 0.2
2008
EoR
• SKADS (europe)
0.1 – 25
2015++ HI survey (aperture array)
• xNTD (Oz)
0.7 – 1.4
2010
HI survey (FPA)
• South Africa
0.7 – 1.4
2010
HI Survey (FPA)
• SKA-TDP (USA)
0.3 – 25
2010
Nd
Goal 4: Hubble constant through direct
measurement: Water Maser Disks (Greenhill)
• Future 1% measures of CMB and related require
1% measure of Ho for fully constrained
cosmological parameters: covariance
• Water masers disks into the Hubble flow can
provide direct measure of Ho to 1%
dh
Case for frequencies up to 45 GHz: Thermal objects
Rayleigh-Jeans curve
implies thermal objects
are a factor four stronger
(in Jy) at 45GHz relative
to 22 GHz
=> a 10% demonstrator
becomes 40% of the SKA
10% demonstrator