The Transient Radio Sky Astrophysical and Artificial

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SKA in context
z8
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Fields of View
1deg2 With Full Sensitivity at subarcsec
resolution
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RMS sensitivity in 8hrs at 1.4 GHz 23 nJy
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China KARST Canada LAR US Large-NSmall-D Aus
tralia Luneburg Lenses Europe phased array
Australia Cylindrical Telescopes
India Preloaded parabolas

• White Papers issued
• for each concept in 2002
• Reviewed by EMT/ISAC and revised 2003

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Concept USA Nd

• 4640 x 12m parabolic antennas
• Full Xcorr inner 2300 ants (35 km), outer
  stations of 13 ants
• Advantage works to high frequency (gt 20 GHz)
• Disadvantage no full-sky, full-array
  multibeaming

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Concept Euro nD Phased arrays
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SKA poster (multi-beams)
Advantages many simultaneous beams, fast
response Disadvantage Max. frequency 1.4 GHz
Disadvantage max freq 1.4 GHz
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SKA and VLBI
SKV
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The SKV Scaled arrays to 5000 km
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Centimeter observations of thermal sources at mas
resolution
X PP-disks
X NGC1068 Disk
SKV

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SKV Science

• Dust obscured star and black hole formation
  history
• a. starburst AGN connection/discrimination
  T_B(5s,8hrs,20mas,1.4GHz)200K (SSCs, EG HII,
  SNR, imaging to z0.5)
• b. counting RSNe to z 3, imaging expansion to
  z0.05
• c. mapping OH megamasers to z 0.3
• Imaging water maser disks to z0.06
• Imaging (faint) GRBs
• High redshift radio absorption lines (HI,
  molecular) probing dense ISM, evolution physical
  constants
• (SM)BH physics low luminosity AGN --
  Jet/accretion disk connection, XDAFs,
  Extragalactic microQuasars

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SKV Science

• Protoplanetary disks, jets, and planets imaging
  thermal emission at subAU scales, astrometry
  Jovian planets around non-flaring solar-type
  stars to 50pc (30,000 stars!), Jupiter bursts to
  100 pc.
• Solar-Stellar connection imaging coronal
  activity to 5pc (30 stars)
• Extragalactic pulsars/stellar masers proper
  motions
• Geodesy millimeter accuracy gt Earth quake
  prediction?
• Scattering and Scintillation uas astronomy,
  turbulent ISM/IPM

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SKV Science

• Proper motions of low luminosity AGN to Virgo
  mass map of the local supercluster
• Epoch of Reionization 21cm absorption by
  neutral IGM toward 1st radio loud AGN/GRBs/Star
  forming galaxies
• For more details see http//www.euska.org/worksho
  ps/hr_ws_MPIfR_Bonn.html

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Epoch of Reionization End of Dark age sets the
fundamental benchmark for cosmic structure
formation formation first luminous objects
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Evolution of the neutral IGM (Gnedin) Cosmic
Phase transition
HI fraction
Ionizing intensity
density
Gas Temp
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Discovery of the EoR
Gunn-Peterson Absorption gt f(HI) gt 0.01 at
z6.3 (Fan et al. 2002)
CMB large scale (gt10deg) polarization gt f(HI) lt
0.5 at z17 (Kogut et al. 2003)
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Studying the pristine IGM beyond the EOR HI 21cm
observations with the SKA and LOFAR
SKA A/T 20000 m2/K gt nJy sensitivity at 1.4
GHz, mJy at 200 MHz Freq range 0.1 to 20
GHz Resolution 0.1 at 1.4GHz
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Imaging the neutral IGM at z8.5 (Tozzi 2002)
Galaxies 6uJy at 2 res ( 20 mK) tCDM and OCDM
30 Mpc comoving
QSOs 3uJy/beam at 2 res With and without soft
Xray pre-heating.
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Difficulty with (LSS) emission observations
Confusion
Continuum sources (di Matteo et al.2002)
Free-Free emission (Oh Mack 2002)
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Cosmic Web after reionization Ly alpha forest
(d lt 10)
142223 z3.62 Womble 1996
N(HI) 1e13 -- 1e15 cm-2, f(HI/HII) 1e-5 --
1e-6 gt Before reionization N(HI) 1e18 1e21
cm-2
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Cosmic Web before reionization HI 21cm Forest
Z9
Z7
Carilli, Gnedin, Owen 2002
Absorption best done at (sub)arcsecond
resolution gt 1000 km baselines

• Mean optical depth (z 10) 1 Radio
  Gunn-Peterson effect
• Narrow lines (1 to 10, few km/s) HI 21cm
  forest (d 10)

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SKA observations of absorption before the EOR A/T
2000 m2/K 240 hrs 1 kHz/channel
z 10
z 8
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Absorption in primordial disks toward
GRBs/Starbursts?
N/Dz ltlt minihalos and IGM (lt1e-4x) but tgtgt
minihalos and IGM (gt50x) gt Use much fainter
radio sources (0.1 mJy) GRB afterglow within
disk? or Starburst radio emission?
Furlanetto Loeb 2002
t gt 1
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Radio sources beyond the EOR?

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Luminous radio sources at very high z
Radio galaxy 0924-220 (van Breugel et al) z
5.19 S_151 600 mJy
Quasar 09135821 (Momjian et al.) z 5.12
S_151 150 mJy
M_BH 1e9 M_sun
10mas
1

• (sub)arcsec resolution preferred decrease
  confusion, allow imaging

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CO 3-2 at z6.42
11485251 z6.42
46.6 GHz
VLA detection of CO 3-2 emission from most
distant QSO within the EoR (Walter, Carilli,
Bertoldi) M(dust) 1e8 M_sun M(H_2) 2e10
M_sun M_BH 1 5e9 M_sun M_dyn gt 1e10 M_sun
S_190MHz 0.1 mJy predicted if dust is heated
by star formation
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Radio sources beyond the EOR sifting problem
(1/1400 per 20 sq.deg.)
1.4e5 at z gt 6
S_120 gt 6mJy
2240 at z gt 6
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• Summary SKA study of the EoR
• Complex reionization -- GP F(HI) gt 0.01 at
  z6.4, CMB pol F(HI) lt 0.5 at z 20.
• Neutral IGM is opaque gt need observations
  longward of 1mm
• Neutral, pristine IGM realm of low frequency
  radio astronomy.
• HI 21cm emission probes large scale structure.
• HI 21cm absorption probes intermediate to small
  scale structure (radio GP effect, 21cm forest,
  minihalos, proto-disks) (sub)arcsec
  resolution decreases confusion, allows imaging.
• Constrain z_reion, detailed structure formation,
  nature of first luminous sources, ionizing
  background, IGM heating and cooling.
• LOFAR should provide first detections of the
  neutral IGM at zgt6.
• SKA will allow for detailed studies.

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ISSC SKA planning schedule

• 2002 Design concept white papers
• 2002 Director Appointed Management plan with
  ISSC
• 2003 Updated design concept white papers
• 2003 White papers on possible locations
• 2004 Updated white papers on locations
• 2005 Choice of SKA location
• 2005 Full Proposals for designs to ISSC
• 2007 SKA facility definition (may merge
  designs)
• 2010-12 SKA construction begins ?
• 2015-17 SKA completed ?

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• ISAC Mandates
• Revise science case and requirements, involving
  larger community, and put in context of future
  capabilities at other wavelengths. Goal new
  Taylor-Braun document by Aug. 2004.
• Evaluate (w. EMT) proposed SKA designs and advise
  ISSC. Goal final design and site choice by
  ISSC in 2007

• Current documentation
• Science with the Square Kilometer Array, R.
  Taylor R. Braun, 1999 (www.skatelescope.org/ska_
  science.shtml)
• Perspectives on Radio Astronomy Science with
  Large Antenna Arrays, ed. M. van Haarlem, 1999
  (ASTRON)
• SKA memo series Groningen (2002), Bologna
  (2002), and Berkeley(2001), science working group
  reports (www.skatelescope.org/ska_memos.shtml)

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Discovery of the EOR (Becker et al. 2002)
Fast reionization at z 6.3 gt opaque at l_obs
lt 1 mm
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Lower limit to z_reio GP Effect
Fan et al. 2002
White et al. 2003
f(HI) gt 0.01 at z 6.3
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Upper limit to z_reio CMB anisotropies
Briggs
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Thompson scattering gt polarization

• Large scale structure (10s deg) gt relic of EOR
• t Ln_es_e 0.17

gt z_reion 10 to 20 (Kogut et al. 2003) f(HI)
lt 0.5 at z 20

Kogut et al. WMAP
f(HI) gt 0.01 at z 6.3
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IGM Thermal History Spin, CMB, Kinetic and the
21cm signal
Tozzi 2002
T_CMB
T_s
T_K

• Initially T_S T_CMB
• T_S couples to T_K via Lya scattering
• T_K 0.026 (1z)2 (wo. heating)
• T_CMB 2.73 (1z)

• T_S T_CMB gt no signal
• T_S T_K lt T_CMB gt Absorption against CMB
• T_S gt T_CMB gt Emission

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Evolution of lttemperaturesgt in the simulation
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Confusion by free-free emission during EOR (Oh
Mack 2003)
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Detection limits
Running rms S_120 gt 6 mJy in 240 hrs
KS of noise S_120 gt 12mJy
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Absorption by minihalos (d gt 100) (Furlanetto
Loeb 2002)
N/Dz(minihalos) N/Dz(IGM) 10/unit z at z8,
t gt 0.02
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Inverse Compton losses off the CMB
U_B (radio lobe)
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CDM structure formation (PS)
Efstathiou 1995
M_BH 0.006 M_spheroid
N(1e11, z6 8) 3/arcmin2
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Evolution of space density of luminous QSOs (Fan
et al. 2003)
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USS samples (de Breuck et al.)
zgt8 radio galaxies?