Transcript EVN observations the next generation

problem of weak radio emission
FR II or FR I ?
The origin of weak radio emission in
Type-2 radio-quit quasars
- the new era of mJy VLBI observations -
8th European VLBI Network Symposium, Torun, Poland
Hans-Rainer Klöckner
Alejo Martínez-Sansigre
Mike Garrett
Steve Rawlings
Paul Alexander
David Green
Julia Riley
Intro - the sample
type I good understanding optical LF z ~ 2
population of obscured radio quit quasars
postulated from hard X-ray background
 give hint of black-hole growth
Spitzer FLS VLA-B
Condon et al. AJ 2003
~# 700 deg-2
S3.6 mm ≤ 45 mJy 
z > 2: ~1.2 mm exclude type I
S24 mm > 300 mJy 
z > 2: L ≥ 0.2 L* Quasar break luminosity
2 mJy ≥ S1.4GHz ≥ 350 mJy 
Exclude ULIRG & FRII
[Martínez-Sansigre et al. Nature 2005]
 population of 21 distant type II quasars in 3.8 sq.degrees
Intro - sub-sample
Z > 2:
 population of 11 distant type II quasars
in 3.8 deg2 redshift range 2 - 4.169
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]
composite spectrum
Normalized 100%; <
2000 kms-1
36%
9%
9%
Martínez-Sansigre et al.
MNRAS 2006
4%
the idea
HDF: J123642 + 621331 z = 4.424
WSRT 489 mJy  VLA-A 467 mJy 
MERLIN 472 mJy  EVN 248 mJy
MERLIN 1.4 GHz [Muxlow et al. 2005]
EVN 1.4 GHz [rms 40mJy; Garrett et al. 2001]
dusty , starforming galaxy
+ embedded AGN
EVN observations
3 x 12 hrs in October & November 2005
EF, (WB), JB, ON, MC, NT, TR, UR, SH
J1722+5856
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Correlated: December / January 2005/2006
Bob, Lisa, Rebeca
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MK5 recording system 9 x 3275 Gbytes !!!
8 IF
32 channels
0.5 MHz per channel
 128 MHz band !!!
EVN observing strategy
8 IF, 4-28 channels 200 channels  123.5 MHz
centre frequency 1658.24 MHz
J1722+5856
o
separation ~2 deg
flux recovered
J1722+6105
W171156
[131 mJy]
[15.52 mJy ]
o
[VLBA 17.031.3 mJy ]
results
rms ~ 26 mJy; 6-7 rms peak  8 out of 11 72% [AMS01, AMS06, AMS17]
AMS03
AMS12
AMS05
AMS16
AMS09
AMS19
AMS15
AMS21
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 % mJy
Garrett et al. ApJ 2004
HDF + HFF : ~0.5 deg2 2 out of 92 [2%] for [rms ~33mJy]
Garrett et al. A&A 2000
HDF : ~0.5 deg2 4 out of 7 [57%] for [rms ~7mJy]
Seungyoup Chi 2006
Spitzer FLS : 12 out of 20 [< 1deg, 60%] with >2 mJy [rms ~333mJy]
Wrobel et al. ApJ 2004
FIRST : 1.1mJy 71 + 14 out of 256 sources 28-33 %
Porcas et al. 2004
results
expected / observed
2
4.9 GHz flux / observed
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1.5
fraction / spec index
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for Z > 2
~15 GHz versus ~5 GHz
source rest frame
SBN
putting it together
radio
3
FRI / II
9
21
5 19
15
12
optical
I
16
X
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X
type
II
[Martínez-Sansigre et al. sub 2006]
8 out of 11 Sources with EVN detection rate 73 %
radio & infrared selection helps
recover around 50% of flux within the inner 300 pc
AGN feedback could switch off star formation
would expect 4.3 type I quasars 3.8 deg2
8 - 11 type II 1:3
[hard X-ray]
or 1:1
the future
10 -15 years
from mJy to nJy
SKADS
Jarvis et al. In prep.
1deg2