Evolution of radio telescopes (Braun 1996)

SKA in context

Fields of View

Centimeter observations of thermal sources at mas resolution

X NGC1068 Disk

X PP-disks

ISAC Mandates:

1. 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.

2. Evaluate (w. EMT) proposed SKA designs and advise ISSC. Goal: final design and site choice by ISSC in 2007

Current documentation:

1. Science with the Square Kilometer Array, R. Taylor & R. Braun, 1999 (www.skatelescope.org/ska_science.shtml)

2. Perspectives on Radio Astronomy: Science with Large Antenna Arrays, ed. M. van Haarlem, 1999 (ASTRON)

3. SKA memo series: Groningen (2002), Bologna (2002), and Berkeley(2001), science working group reports (www.skatelescope.org/ska_memos.shtml)

SKA Designs ("compliance" matrix)http://www-astro.physics.ox.ac.uk/~sr/ska/ska_matrix.html

Level 1 Science Strawman  China  Europe  India  Ozlens  Ozcyli  USA  Canada 

1: Galactic HI YES UPGRADE? UPGRADE? YES YES YES UPGRADE? UPGRADE?

1: Galactic NT+B YES UPGRADE? NO YES UPGRADE? YES YES UPGRADE?

2: Transients UPGRADE? NO NO NO NO NO NO NO

2: Pulsars UPGRADE? NO NO NO NO NO NO NO

2: SETI UPGRADE? NO NO NO NO NO NO NO

3: EOR UPGRADE? NO UPGRADE? UPGRADE? UPGRADE? UPGRADE? UPGRADE? UPGRADE?

4: HI surveys / LSS YES UPGRADE? UPGRADE? YES YES YES YES YES

4: Continuum surveys

UPGRADE? NO NO UPGRADE? UPGRADE? UPGRADE? UPGRADE? UPGRADE?

4: CO surveys YES NO NO UPGRADE? NO UPGRADE? YES YES

5: Hi-z AGN UPGRADE? NO NO YES UPGRADE? YES YES UPGRADE?

5: Inner AGN UPGRADE? NO NO UPGRADE? NO UPGRADE? YES UPGRADE?

6: Protoplanetary systems

UPGRADE? NO NO UPGRADE? NO UPGRADE? YES YES

7: CMEs UPGRADE? NO UPGRADE? UPGRADE? YES YES UPGRADE? YES

7: SS bodies YES NO NO UPGRADE? NO UPGRADE? UPGRADE? YES

8: IGM non thermal YES UPGRADE? NO YES YES YES UPGRADE? UPGRADE?

8: IGM thermal UPGRADE? NO NO UPGRADE? NO NO YES UPGRADE?

9: Spacecraft Tracking

UPGRADE? NO NO UPGRADE? NO NO YES UPGRADE?

9: Geodesy UPGRADE? NO NO UPGRADE? NO UPGRADE? UPGRADE? UPGRADE?

Notes: Level-1 science may still be missing. 'Level-1' probably not a uniform measure across the WGs.

Last updated: 10th August 2002

Compliance Matrix: www-astro.physics.ox.ac.uk/~sr/ska/ska_matrix.html

Highest z HI emission to date: 110 hours VLA + GMRT

Verheijen, Dwarakanath, van Gorkom

kpc60Dkpc120DM101M(HI) optHIsun10

SMC

M 101

M 51

Maximum redshift for a 360 hour integration with SKA

Star formation with z

Crucial epoch

2000 galaxies/ deg

100 000

30 000

z = 2 z = 4

z = 0.45

z = 0.9

M101 z = 0.2

Imaging to z=1 => TF distances => peculiar motions

Braun 1996

SKA HI Survey: ‘Sloan x 100’

1000 hrs, 1000 sq.deg.

Evolution of gas and dark matter content of galaxies

Origin of Hubble sequence and density-morphology relation

Evolution of LSS and cluster velocity dispersions

Tully-Fisher distances: Peculiar motions => evolution of bias parameter

SKA continuum survey: HDFx10000

5e8 sources at > 0.3 uJy over 1000 sq.deg.

Star formation history of the universe unbiased by dust

Massive black hole formation and accretion history

Hopkins 1999

Dust obscured star formation at high z:

The brightest mm source in HDF not detected by HST!

Elliptical galaxy formation in dusty, high z starbursts?

Maximum redshift for a 360 hour integration with SKA

resolved flux (0.1”) total flux (1”)

M 33

NGC 6946

resolved flux total fluxM 51

Thermal flux

HI 21cm absorption in deep, wide surveys

1229-021 Briggs 1996

z_abs = 0.4

N(S>1mJy) = 36000 => O(50000) HI 21cm absorption lines by damped

Ly alpha systems (1e20 /cm/cm, T_spin = 1000 K)

Dense ISM in nascent galaxies

Dust unbiased QSO statistics: ‘Red quasars’ and ‘dark’ gravitational lenses

Evolution of physical constants

OH megamasers in deep HI surveys: beacons to high z, merging starburst galaxies

Briggs 1995

Highest z CO emission to date: 24 hrs/source w. VLA M(H_2) = few e11 M_sun

1202-0725 z =4.69

CO(2-1)

2322+1944 z = 4.12

CO(2-1)

1331-0417 z = 4.41

CO(2-1)

0827+5255 z = 3.91

CO(1-0)

0827+5255 at z=3.9: An ‘Einstein Arc’ in CO

8 GHz

HST

CO(2-1)

300 pc

SKA and CO

22 GHz

43 GHz

M(H_2) = few e9 M_sun

Optimal CO surveys: ‘speed of discovery’

Carilli and Blain 2002

HCN (89 GHz): Dense gas + starburst tracer?

Solomon 2001

Conflict I: low vs. high frequency?

HI Surveys require frequencies < 1.4 GHz

CO Surveys require frequencies > 20 GHz

Can we do both with one design?

Epoch of Reionization:

Evolution of the neutral IGM (Gnedin): ‘Cosmic Phase transition’

HI fraction

density Gas Temp

Ionizing intensity

Gunn-Peterson effect

Barkana and Loeb 2001

Discovery of the EOR? (Becker et al. 2002)

Fast reionization at z = 6.3

=> opaque at _obs < 1 m

Fan et al. 2002

Lower limit to z_reio: GP Effect

F(HI) > 0.01 at z = 6.3

Briggs

Upper limit to z_reio: CMB anisotropies

Studying the IGM beyond the EOR: HI 21cm observations with the Square Kilometer Array and LOFAR

_21cm = 1e-8 _Lya

Temperatures: Spin, CMB, Kinetic and the 21cm signal

•Initially T_S= T_CMB

•T_S couples to T_K via Lya scattering

•T_K = 0.026 (1+z)^2 (wo. heating)

•T_CMB = 2.73 (1+z)

•T_S = T_CMB => no signal

•T_S = T_K < T_CMB => Absorption against CMB

•T_S > T_CMB => Emission

T_K

T_CMBT_s

Tozzi 2002

HI 21cm Emission

Difficulty with (LSS) emission observations: confusion by foreground radio sources (di Matteo 2001)

1422+23 z=3.62 Womble 1996

N(HI) = 1e13 -- 1e15 cm^-2, f(HI/HII) = 1e-5 -- 1e-6

=> Before reionization N(HI) =1e18 – 1e21 cm^-2

Cosmic Web after reionization = Ly alpha forest ( <= 10)

Cosmic Web before reionization: HI 21cm Forest

)1()10

1)((008.0 2/1

HI

S

CMB fz

T

T

•Mean optical depth (z = 10) = 1% = ‘Radio Gunn-Peterson effect’

•Narrow lines (1 to 10%, few km/s) = HI 21cm forest (= 10)

Carilli, Gnedin, Owen 2002

z = 10 z = 8

SKA observations of absorption before the EOR

A/T = 2000 m^2/K 240 hrs 1 kHz/channel

Radio sources beyond the EOR?

0924-220 z = 5.19 S_151 = 600 mJy

0913+5821 z = 5.12 S_151 = 150 mJy

1”

Inverse Compton losses off the CMB

= U_B (radio lobe)

Radio sources beyond the EOR:

sifting problem (1/1400 per 20 sq.deg.)

2240 at z > 6

1.4e5 at z > 6

USS samples (de Breuck et al.)

Conflict II: Long vs. Short baselines?

EOR emission requires arcmin resolution => baselines < 5km

EOR absorption requires arcsec resolution => baselines > 300km

Both are sensitivity limited: where to put our collecting area?