Science with SKA:

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Science with SKA
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• The SKA will provide continuous frequency
  coverage from 50 MHz to 14 GHz in the first two
  phases of its construction.
• A third phase will then extend the frequency
  range up to 30 GHz.
• Phase 1 Providing 10 of the total collecting
  area at low and mid frequencies
• Phase 2 Completion of the full array at low and
  mid frequencies

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SKA-low array a phased array of simple
dipole antennas to cover the frequency
range from 50 to 350 MHz. SKA-mid
array to cover the frequency range 350 MHz to
14 GHz. SKA-survey array - a compact
array of parabolic dishes of 1215
meters diameter each for the medium-frequency
range, each equipped with a multi-beam,
phased array feed with a huge field of
view

• SKA1-low (Aus)
• SKA1-mid (SA)
• SKA1-survey (Aus)

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SKA1-low

• Australia
• Main driver highly redshifted 21 cm HI line from
  the Epoch of Reionization and earlier
• pulsars, magnetized plasma, extrasolar planets
• 250000 antennas
• 50-350 MHz
• 1 km radius core
• 45 km maximum baseline
• 20 deg2 field of view

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SKA1-mid

• South Africa
• pulsars, nearby to mid-z HI line, high
  sensitivity continuum sources
• 250 15m dishes (MeerkatSKA1 dishes)
• 0.35-3 GHz ready for additional receivers
• 100 km maximum baseline

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SKA1-survey

• Australia
• survey large areas of sky in line and continuum,
  transients
• 100 15m dishes (ASKAPSKA1 dishes)
• 0.6-1.7 GHz
• 25 km maximum baseline
• PAF (Phased Array Feed)

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Sensitivity Survey Speed 3 days to do survey
like NVSS
( 10 months VLA over 3 years)
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(No Transcript)
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On 18 August 2014, Philip Diamond, Director
General of the SKA Organisation, visited the 54th
Research Institute of China Electronics
Technology Group Corporation (CETC54) in
Shijiazhuang, about 300km south west of Beijing
to see a complete prototype SKA antenna The
Chinese antenna is an offset Gregorian dual
reflector. The main and sub reflectors were made
of Carbon Fiber Reinforced Polymers (CFRP), based
on single piece panel and surface metallizing
technology. The main reflector size is 18m
15m, the sub reflector size is 5m 4.7m.
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Hubble Deep Field with the SKA
SKA 8 hour integration (simulation by Hopkins et
al.) ? 2200 sources
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HDF simulation based on source counts
Starburst are blue, AGN are red. A beam of 0.1
is needed to minimize confusion.
? Star formation history of the Universe ? Star
formation vs nuclear activity
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Key Science Projects Origin of the Universe
1. Formation of first objects/EoR 2.
Evolution of galaxies/ Cosmology/ Dark energy
Fundamental Physics 3.
Pulsars/ General Relativity/ Gravitational Waves
4. Cosmic Magnetism Origin of life
5. Cradle of life and intelligent life
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Probing the Dark Ages
COSMIC HISTORY OF THE UNIVERSE
The Dark Ages Era of the Universe 300 000 - 1 000
000 000 yr after the Big Bang during which the
first stars and galaxies formed
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Probing the Dark Ages
SKA Role Detect and image hydrogen in the dark
ages, provide 3D maps of the early cosmic web,
shed light on the physics of the formation of the
first objects in the Universe HI _at_ z 5 ?
1.3 m, 240 MHz z 10 ? 2.3 m,
130 MHz z 20 ? 4.4 m, 68 MHz CO
_at_ z 5 ? 1.6 cm, 19 GHz z 10
? 2.7 cm, 11 GHz z 20 ? 5.5
cm, 5.5 GHz 20 h exposure per pointing, 400
pointings with 50o field of view (HI,
conservative) -gt 1 yr
18.3
16.1
14.5
13.2
12.1
11.2
10.4
9.8
9.2
8.7
8.3
7.9
7.5
7.2
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Galaxies/cosmology/dark matter/dark energy
The Nature of Dark Energy
Distribution of galaxies in the sky have a
characteristic lenght scale which depends on
models of dark energy SKA Role Locate and
measure spatial distribution of galaxies via
their hydrogen emission
(3.5 HYDROGEN)
Composition of the Universe
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Galaxies/cosmology/dark matter/dark energy
The Nature of Dark Energy
35.000 galaxies in 3D space to z 1.5 in a 4 h
pointing All sky survey 109 galaxies X 1000
Volume improvement Weak lensing -- Planck --
EUCLID
(3.5 HYDROGEN)
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Fundamental Physics How Gravity works

• Pulsars have extreme physical properties
• highest gravitational fields 200000 x solar
• most accurate known clocks 10-9 s
• Physics may be different in strong GR
• SKA role
• Blind survey will find 20 000 pulsars
• in our Galaxy
• many in binary systems and
• exotic systems
• 1000 millisec pulsars

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Fundamental Physics How Gravity works
Identify and time pulsars with nano-second
accuracy

• Find them!
• Time them!
• VLBI them!

Sensitive gravity wave detector
Test GR around Black Holes
-- LIGO -- LISA
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The Origin of Cosmic Magnetism

• Magnetism is one of the 4 fundamental forces
• Magnetic fields are crucial in
• Star, galaxy large scale structure formation
• turbulence gas motions
• acceleration propagation of cosmic rays
• Fundamental unsolved problem
• Exotic origin (phase transitions, strings)
• Seed fields (turbulence, instabilities)
• Amplification

Magnetic Fields role in star formation?
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The Origin of Cosmic Magnetism
SKA role

• Very powerful in the detection of total intensity
  and
• polarized emission and in RM
  measurements
• First detailed 3D picture of cosmic magnetic
  field
• Polarization studies of 100 000 000 sources
• 10000 x improvement
• SKA instant RMs and position , sP 0.1 microJy,
  100 h obs
• ? 1.4 GHz, ?? 400 MHz
• - for P 1 µJy ?? ? 2.5o,
  ?RM ? 2 rad/m2,
• - for P 10 µJy ?? ? 0.3o,
  ?RM ? 0.2 rad/m2

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The Cradle of Life

• Test conditions for life
• elsewhere in the Universe
• - Image proto-planetary
• disks in formation, movies,
• composition
• Probe the Habitable zone
• in disks (mas resolution)
• Detect complex molecules
• - Search for Extraterrestial Intelligence
• Airport radars _at_ 50 l.y. ? 500
  stars
• Ionospheric radar _at_5000 l.y. ?
  600 000 000 stars

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Exploration of the unknown
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Pathfinders LOFAR EoR, magnetism,
survey eMERLIN galaxy evolution
(eMERGE) Precursors ASKAP galaxy and BH
evolution, LSS, stars and stellar
systems, magnetism (EMU,
POSSUM) MeerKAT Pulsar Timing, HI survey,
SFG and AGN Murchison Widefield
Array (MWA)
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Jetted AGN studies have been considered a
prominent science case for SKA, and were included
in several different chapters of the previous SKA
Science Book (Carilli Rawlings 2004).
SKA1 will enable such studies for large samples
of jets, while VLBI observations involving SKA1
will provide the sensitivity for pc-scale
imaging, and the full SKA (with its extraordinary
sensitivity and dynamic range) will allow us for
the first time to resolve and model the weakest
radio structures in the most powerful radio-loud
AGN.
in particular Band 5 receivers in VLBI mode
(Paragi et al. 2014) will provide
milliarcsecond resolution, which corresponds to
parsec scales for a broad redshift range. The
polarization capabilities will be particularly
relevant
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Very Long Baseline Interferometry with the SKA
Zsolt Paragi, Leith Godfrey, Cormac Reynolds,
Maria Rioja, et al.
Adding VLBI capability to the SKA arrays will
immensely broaden the science of the SKA, and it
is entirely feasible. SKA-VLBI can be initially
implemented by providing phased-array outputs for
SKA1-MID and SKA1-SUR, and using these extremely
sensitive stations with other radio telescopes,
and in the full SKA by realising a distributed
configuration providing baselines up to thousands
of km, merging it with existing VLBI networks.
The motivation for and the possible realization
of SKA-VLBI is described in this paper.
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Flight Cagliari-Bologna, after the EVN symposium