LOFAR LOw Frequency Array most distant high redshift

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LOFAR LOw Frequency Array => most distant, high redshift Universe !? Consortium of international

LOFAR LOw Frequency Array => most distant, high redshift Universe !? Consortium of international partners… Dutch ASTRON USA Haystack Observatory (MIT) USA Naval Research Lab … `best site’ = WA … … … Novel `technology telescope’ - array design => no moving parts - huge, fast data network huge collecting area multi-beaming (cheap)

Dutch View ~ 400 km

Dutch View ~ 400 km

a Lofar `station’

a Lofar `station’

LOFAR ATCA GMRT VLA ALMA 350 m 10 MHz ground based radio techniques

LOFAR ATCA GMRT VLA ALMA 350 m 10 MHz ground based radio techniques

LOFAR 350 m 10 MHz ground based radio techniques

LOFAR 350 m 10 MHz ground based radio techniques

…this workshop… mml astronomy… Simularities: sky noise rapid phase variation Differences: solid angle of

…this workshop… mml astronomy… Simularities: sky noise rapid phase variation Differences: solid angle of receiving element survey …. ALMA atmosphere LOFAR Gal. Synchrotron ionosphere tiny (l/D of dish) nearly all sky mosaic all-sky calibration

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation - mapping the neutral clouds in IGM as first sources of ionising radiation appear at redshifts between 7 and 20(? )

Top LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation -

Top LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation - mapping of neutral residue of IGM as first sources of ionising radiation appear at redshifts between 7 and 20(? ) t. UV< 1 … (Gunn-Peterson Effect) Z = 20 ……………. 15 ………. 10 8 cold HI 7 6 HII 70 MHz 90 MHz 130 160 190 MHz

WMAP result => Z ~ 15 to 20 2 Eo. Rs ? ? ?

WMAP result => Z ~ 15 to 20 2 Eo. Rs ? ? ? … or… prolonged, patchy Eo. R ? ? ? Z = 20 cold HI HII 15 10 8 7 warm HI Pop III stars: @ 500 Solar mass 6 HII

LOFAR and SKA distributed star formation … Quasar 10 arcmin

LOFAR and SKA distributed star formation … Quasar 10 arcmin

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation - • mapping of neutral clouds in IGM as first sources of ionising radiation appear at redshifts between 7 and 20(? ) Highest redshift radio sources - Steep spectrum selection (a < -2) => 1 source per sample of ~30, 000 => catalog of background radio sources for intervening HI absorption

Spectral Index Redshift

Spectral Index Redshift

Spectral Index Redshift

Spectral Index Redshift

Mapping intervening protogalaxies in 21 cm absorption SKAMP-III compatible !

Mapping intervening protogalaxies in 21 cm absorption SKAMP-III compatible !

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation - • mapping of neutral clouds in IGM as first sources of ionising radiation appear at redshifts between 7 and 20(? ) Highest redshift radio sources - • Steep spectrum selection (a < -2) => 1 source per sample of ~30, 000 => catalog of background radio sources for intervening HI absorption 3 -D mapping of the Galactic non-thermal emission - uses free-free absorption by known extended thermal sources will determine the origin of the Galactic cosmic ray flux

Radio sky in 408 MHz continuum (Haslam et al) (Dominated by synchrotron emission from

Radio sky in 408 MHz continuum (Haslam et al) (Dominated by synchrotron emission from relativistic electrons)

holes in the Galactic radio sky… Optically thick thermal plasma … HII regions

holes in the Galactic radio sky… Optically thick thermal plasma … HII regions

mapping the synchrotron emission in front of … and behind the opaque thermal sources

mapping the synchrotron emission in front of … and behind the opaque thermal sources ….

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation - • Mapping of neutral clouds in IGM as first sources of ionising radiation appear at redshifts between 7 and 20(? ) Highest redshift radio sources - • Steep spectrum selection (a < -2) => 1 source per sample of ~30, 000 => catalog of background radio sources for intervening HI absorption 3 -D mapping of the Galactic non-thermal emission - • uses free-free absorption by known extended thermal sources will determine the origin of the Galactic cosmic ray flux Transient and bursting sources - no moving parts => nearly instantaneous response to trigger events central core is an all-sky (hemisphere) monitor sensitive to non-thermal, coherent emission events, should they exist(? )

The SUN Coronal Mass Ejections, CMEs

The SUN Coronal Mass Ejections, CMEs

Frank’s 3 favorites LOFAR astronomical science drivers • Highest redshift radio sources - •

Frank’s 3 favorites LOFAR astronomical science drivers • Highest redshift radio sources - • Steep spectrum selection (a < -2) => 1 source per sample of 10, 000 => catalog of background radio sources for intervening HI absorption #3 #1 21 cm emission/absorption from Epoch of Reionisation - • Tomography of neutral residue of IGM as first sources of ionising very tough to achieve sensitivity: high risk / high gain radiation appear at redshifts between 7 and 20(? ) 3 -D mapping of the Galactic non-thermal emission - • uses free-free absorption by known extended thermal sources will determine the origin of the Galactic cosmic ray flux Transient and bursting sources - #2 no moving parts => nearly instantaneous response to trigger events central core is an all-sky (hemisphere) monitor sensitive to non-thermal, coherent emission events, should they exist(? )

Dipole + ground plane conducting ground plane

Dipole + ground plane conducting ground plane

Dipole + ground plane Ioe i 2 pft equivalent to dipole plus mirror image

Dipole + ground plane Ioe i 2 pft equivalent to dipole plus mirror image -Ioe i 2 pft

Dipole element response Ioe i 2 pft h equivalent to dipole plus mirror image

Dipole element response Ioe i 2 pft h equivalent to dipole plus mirror image h -Ioe i 2 pft

q = zenith angle Dipole Ioe i 2 pft h h equivalent to dipole

q = zenith angle Dipole Ioe i 2 pft h h equivalent to dipole plus mirror image -Ioe i 2 pft 2 P(q) ~ sin [2 ph cos(q)/l] (maximize response at q=0 if h=l/4 )

Dipole q Ioe i 2 pft azimuth 2 f h 2 P(q) ~ sin

Dipole q Ioe i 2 pft azimuth 2 f h 2 P(q) ~ sin [2 ph cos(q)/l] {1 - sin q sin 2 f }

q q f q f f

q q f q f f

The `sin projection’ of hemisphere onto a plane: The Sky above dipole

The `sin projection’ of hemisphere onto a plane: The Sky above dipole

‘sin projection’ line of constant zenith angle

‘sin projection’ line of constant zenith angle

‘sin projection’

‘sin projection’

‘sin projection’ gives little weight to sky close to horizon !

‘sin projection’ gives little weight to sky close to horizon !

X Y

X Y

Y X

Y X

Dipole over ground plane Tuned for 150 MHz Y X

Dipole over ground plane Tuned for 150 MHz Y X

Dipole Tuned for 150 MHz 120 180 150 210 MHz 240 MHz

Dipole Tuned for 150 MHz 120 180 150 210 MHz 240 MHz

What are these things?

What are these things?

Crossed Dipoles for dual polarization conducting plane

Crossed Dipoles for dual polarization conducting plane

Droopy Dipoles for broad-band, dual polarization LOFAR-Low Band dipole element

Droopy Dipoles for broad-band, dual polarization LOFAR-Low Band dipole element

4 x 4 array of dipoles on ground plane - the ‘LOFAR-High band’ element

4 x 4 array of dipoles on ground plane - the ‘LOFAR-High band’ element h s s (many analogies to gratings for optical wavelengths)

4 x 4 Tuned for 150 MHz sin projection

4 x 4 Tuned for 150 MHz sin projection

ZA = 0 deg 45 15 60 30 75

ZA = 0 deg 45 15 60 30 75

4 x 4 Patterns • • ZA = 30 deg tuned for 150 MHz

4 x 4 Patterns • • ZA = 30 deg tuned for 150 MHz 120 150 180 210 240

Lofar stations ? ? ?

Lofar stations ? ? ?

a `station’ = 101 `4 x 4 tiles’ Size in l

a `station’ = 101 `4 x 4 tiles’ Size in l

a `station’ as 101 omni-directional elements Size in l

a `station’ as 101 omni-directional elements Size in l

Station Beam: no 4 x 4 envelope

Station Beam: no 4 x 4 envelope

Station Beam: using 4 x 4 envelope

Station Beam: using 4 x 4 envelope

Station Beam: 4 x 4 envelope and taper

Station Beam: 4 x 4 envelope and taper

Station Beam

Station Beam

Offset Station Beam Centered station beam inside the 4 x 4 beam

Offset Station Beam Centered station beam inside the 4 x 4 beam

Latitude: +53. 5 deg Decl 4 x 4: 45 Offset: 5 @ p. a.

Latitude: +53. 5 deg Decl 4 x 4: 45 Offset: 5 @ p. a. 45

Slices through 4 x 4 Beam And Station beams taper

Slices through 4 x 4 Beam And Station beams taper

a `station’ = 101 `4 x 4 tiles’ Size in l

a `station’ = 101 `4 x 4 tiles’ Size in l

Zenith no offset

Zenith no offset

Zenith + o 5 offset

Zenith + o 5 offset

Radio sky in 408 MHz continuum (Haslam et al)

Radio sky in 408 MHz continuum (Haslam et al)

-30 deg north east west south

-30 deg north east west south

North Latitude -30 East

North Latitude -30 East

North Latitude +53. 5 East

North Latitude +53. 5 East

+53. 5 deg north east west south

+53. 5 deg north east west south

-30 deg north east west south

-30 deg north east west south

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation • Highest redshift radio sources [ => catalog of background radio sources for intervening HI absorption ] • 3 -D mapping of the Galactic non-thermal emission • Transient and bursting sources

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation

Top 4 LOFAR astronomical science drivers • 21 cm emission/absorption from Epoch of Reionisation • Highest redshift radio sources [ => catalog of background radio sources for intervening HI absorption ] • 3 -D mapping of the Galactic non-thermal emission • Transient and bursting sources

Effect of moving station beam w. r. t. 4 x 4 beam ZA =

Effect of moving station beam w. r. t. 4 x 4 beam ZA = 30 deg for 4 x 4 5 deg Offset for station beam

GAIN d. B

GAIN d. B

GAIN d. B 2. 5 deg offset

GAIN d. B 2. 5 deg offset

GAIN d. B 7. 5 deg offset

GAIN d. B 7. 5 deg offset

GAIN d. B

GAIN d. B

GAIN d. B 4 x 4 ZA = 30 deg

GAIN d. B 4 x 4 ZA = 30 deg