problem of weak radio emission

FR II or FR I ?

Hans-Rainer KlöcknerAlejo Martínez-Sansigre

Mike GarrettSteve RawlingsPaul Alexander

David GreenJulia Riley

The origin of weak radio emission in The origin of weak radio emission in Type-2 radio-quit quasarsType-2 radio-quit quasars

- the new era of - the new era of Jy VLBI observations -Jy VLBI observations -

8th European VLBI Network Symposium, Torun, Poland

Intro - the sample

S24 m > 300 Jy z > 2: L ≥ 0.2 L* Quasar break luminosity

population of 21 distant type II quasars in 3.8 sq.degrees

[Martínez-Sansigre et al. Nature 2005]

S3.6 m ≤ 45 Jy z > 2: ~1.2 m exclude type I

Condon et al. AJ 2003

Spitzer FLS VLA-B

2 mJy ≥ S1.4GHz ≥ 350 Jy Exclude ULIRG & FRII

type I good understanding optical LF z ~ 2population of obscured radio quit quasars postulated from hard X-ray background give hint of black-hole growth

~# 700 deg-2

Normalized 100%; < 2000 kms-1

36%

9% 9% 4%

Martínez-Sansigre et al.MNRAS 2006

composite spectrum

Intro - sub-sample population of 11 distant type II quasars in 3.8 deg2 redshift range 2 - 4.169

Z > 2:

redshifts: 7 spec & 3 photo [AMS01, AMS09,AMS21], 1 not obs [AMS15]

Optical mR = 23.8 - 25.3 L1.4GHz FRI FRII @ 2.5E24 W / (Hz sr) [Ledlow & Owen 1996]

MERLIN 1.4 GHz [Muxlow et al. 2005] EVN 1.4 GHz [rms 40Jy; Garrett et al. 2001]

WSRT 489 Jy VLA-A 467 Jy MERLIN 472 Jy EVN 248 Jy

HDF: J123642 + 621331 z = 4.424

the idea

dusty , starforming galaxy+ embedded AGN

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3 x 12 hrs in October & November 2005EF, (WB), JB, ON, MC, NT, TR, UR, SH

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Correlated: December / January 2005/2006

MK5 recording system 9 x 3275 Gbytes !!!

EVN observations

8 IF8 IF32 channels32 channels0.5 MHz per channel0.5 MHz per channel 128 MHz band !!!128 MHz band !!!

J1722+5856

Bob, Lisa, Rebeca

EVN observing strategy8 IF, 4-28 channels 200 channels 123.5 MHzcentre frequency 1658.24 MHz J1722+5856

J1722+6105 W171156

separation ~2 degflux recovered

[131 mJy] [15.52 mJy ]

o

o

[VLBA 17.031.3 mJy ]

results

AMS03

AMS12 AMS16 AMS15 AMS21

AMS19AMS09AMS05

rms ~ 26 Jy; 6-7 rms peak 8 out of 11 72% [AMS01, AMS06, AMS17]

VLBI surveys

NOAO Bootes Field: 0.28 deg2 3 out of 24 & 6 out of 37

detection rate sub-mJy is 8+4-5 % and 29+11

-12 % mJyGarrett et al. ApJ 2004

HDF + HFF : ~0.5 deg2 2 out of 92 [2%] for [rms ~33Jy]Garrett et al. A&A 2000

FIRST : 1.1mJy 71 + 14 out of 256 sources 28-33 %Porcas et al. 2004

Wrobel et al. ApJ 2004

Spitzer FLS : 12 out of 20 [< 1deg, 60%] with >2 mJy [rms ~333Jy]

Seungyoup Chi 2006HDF : ~0.5 deg2 4 out of 7 [57%] for [rms ~7Jy]

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results

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1.5

2

expected / observed

4.9 GHz flux / observed

fraction / spec index

for Z > 2 ~15 GHz versus ~5 GHzsource rest frame

SBN

would expect 4.3 type I quasars 3.8 deg2

8 out of 11 Sources with EVN detection rate 73 %

recover around 50% of flux within the inner 300 pc AGN feedback could switch off star formation

putting it together

radio & infrared selection helps

8 - 11 type II 1:3 [hard X-ray] or 1:1

[Martínez-Sansigre et al. sub 2006]

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3

59 12

151921

X

16

opticaltype

I

II

FRI / II

X

radio

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Jarvis et al. In prep.10 -15 yearsfrom Jy to nJy

the future

1deg2SKADS