Current Status of KVN
Chungsik Oh
KASI@ 2013 VERA User’s meeting

KVN Yonsei
Observatory

KVN UlsanObservatory

KVN Tamna
Observatory

Multi-Frequency Receiving System• Simultaneous Multi-frequency Observation– @ 22/43/86/129GHz– To compensate atmospheric phase fluctuation using
phase solution of low frequency
Beam from subreflector

22GHz

43GHz

129GHz86GHz

Baseline Sensitivity
Base Line Sensitivity@BW = 256MHzBand

Frequency
(GHz)

Tsys
(K)

Gain [Aeff](K/Jy)

SEFD
(Jy)

t_int
(sec)

ΔS (5σ)(mJy/beam)K

21.25-23.25

1000.078 [0.60]

~1300

100

60

Q

42.11-44.11

150

0.078 [0.60]

~1900

60

110

W

85-95

200

0.062 [0.50]

~3200

30

270

D125-142250

0.043 [0.35]

~6000

30470

Need Phase Referencing for longer integration time
: Mutli-Freq PR(MFPR), Fast Position Switching6.7GHz(C), 8GHz(X) at Ulsan• Aperture Efficiency : ~ 60%– w/ Cas A, Tau A• Beam Size

– 7.3’ @ 6.7G
– 6.0’ @ 8.3G

• Tsys ~ 250K

– Trx at Horn ~100K– Trx /w Cal Chopper ~ 200K
• due to large spillover ~ 0.7•••••SEFD : ~3300Jy
LCP only , Simultaneous observation 6.7 & 8.3GHz.
Pointing EL offset : +90” w.r.t. K,Q,W,D
Manual setting of mirror
Fringe Test : 9/24 (EAVN+Sejong 22m)

Operation Summary of 2012-13 Season••••

2012.9 – 2013.622(K), 43(Q), 86(W), 129(D)GHz bands operation
Total Operation Time ~ 4200 hr (incl. VLBI+S.D.)VLBI Operation Time ~ 1300 hr
KVN+VERA : ~430hr

KVN Alone : ~850hr
2195261

26SFR

100Evolved Star

70AGN
Astrometry46434

Evaluation

54180

4-year Operations• VLBI operation time is increasing rapidly• VLBI time of next year : ~3000h
5000
4000

EVN, GMVA

3000

KVN+VERAKVN only

2000

Single-Dish*1000
02009-20102010-20112011-20122012-2013

KVN Proposal Call
• 2 times / year
• Season A (Jan-Jun), Season B (Aug-Dec)• Proposal deadlines :– 2013 July for 2013B– 2013 Oct for 2014A– Feb and Aug from 2014

Open Use Plan
• KVN (VLBI)– 2013 Aug-Dec (2013B): Open to Korea• K,Q : All Users• W,D : Internal users• 1500h : KVN 1000, KVN+VERA 500– 2014 : International Open• K,Q,(W,D)• KVN+VERA Open Use– 2014 Jan (tentative)• Open to Japan and Korea, ~500h• Imaging Observation– Astrometry and phase reference need more test2013B proposals (deadline 07-01)• A first open for proposals of the KVN single
and VLBI observations to domestic
astronomers• 8 TAC (including one foreigner)• 2013-08-15 ~ 2014-01-15• 2000 Hours– VLBI(+test) 50%, KVN+(VERA) 25%– Single 25%• 14/17 (13I+4E) Single, 15/17 (13I+4E) VLBIFringe Survey
 Q-Cal : 43GHz AGN Fringe Survey (Petrov , Lee, et al. AJ 2012)- detected fringe from 637 sources among 799 (78%)- 43GHz Detection Threshold: ~100mJy (5σ)- Expand the number of Q-band calibrators from 150 to ~800
Q-Cal

Previous

K-band Fringe Survey : AGN team
44 GHz Methanol Maser Fringe Survey : SFR team

KVN : 3C84 Images @22GHz
Total Integration Time = 9h, BW = 128MHz
clean map peak : 14.8 Jy/bm, rms : 12.5 mJy/bm, peak/rms ~1200
Beam FWHM : 5.3 x 3.5 (mas) at 89.8deg• KVN-22GHz• VLBA-15GHz

KVN+VERA : M87 Images@22GHz
Int. time=1h, BW=32MHz
clean map peak: 1.17 Jy/bm, rms: 1.7 mJy/bm (1.4), peak/rms~ 700
Beam FWHM : 1.4 x 1.1 (mas) at 1.2deg• KVN+VERA@22GHz• VLBA@15GHzKVN Imaging Capability : Maser
KVN Alone

KVN+VERA

SiO masers of WX Psc

SNR Comparison @ 130 GHz FRINGE SNR
Multi-Frequency Observation : 22, 43, 86, 129 GHz
Target : 3C279

Phase solution of 22GHz data is applied to 129GHz data
Ф129, corrected = Ф129 – Ф22 x (ν129)
ν22300300

77%20020043%Astrometry Performance• Need more test
• Station Coordinate– IVP measurement using dual-band GPS• Position Error ~ 5cm– KVN+VERA 22GHz Geodetic VLBI
• Position Error < 5 cm
• Regular Observation with ~3 month interval• Permanent Dual-band GPS at all KVN stations– Zenith-WET Delay, TEC– Monitoring Station Motion

Summary• KVN open !
– to Korea Users from Aug 2013
– to All Users from 2014

• Available Observation– Fringe Survey and imaging in multi-Freq– MFPR and Fast Position Switching

Hope All of You Enjoy KVN Observation

Thank you