The Power of Multi-Frequency Observations at mm-waves: Astrometry up to 132 GHz with the KVN

Transcription

1 The Power of Multi-Frequency Observations at mm-waves: Astrometry up to 132 GHz with the KVN Maria J. Rioja, Richard Dodson, ICRAR (Australia) Taehyun Jung & Bong Won Sohn KASI (Korea)

2 Overview A mm- VLBI Astrometric Method: Source Frequency Phase Referencing è Outcomes: 1) EffecLve Atmospheric/Instr. CompensaLon, 2) Astrometry (up to 132 GHz) and 3) Increased Coherence DemonstraLon with 4- bands KVN observalons, up to 132 GHz (conlnuum) From RelaLve to Individual Source Shi]s for Image Alignment (NEW) (Brief) Astrophysical ApplicaLons 2

3 Frequency Phase Referencing (FPT) WEAK SOURCES ASTROMETRY Target freq. _ T BETTER SIMULTANEOUS! HIGHER FREQUENCIES OK R = ν / ν Lme Fast Slow Slow φ Α = φ A,GEO + φ A,TRO + φ Α,ΙΟΝ Α,ΙΝST +φ A,STR + 2πn + φ + A φ Α = φ Α,GEO A,TRO Α,ΙΟΝ Α,ΙΝST 2πn R*φ A Α = R*(φ Α,GEO + φ A,TRO + φ Α,ΙΟΝ + φ Α,ΙΝST + 2πn A ) φ Α FPT Non- dispersive Errors: φ A,TRO - R * φ A,TRO = 0 φ A,GEO - R * φ A,GEO = 0 Dispersive Errors: φ A,ION - R * φ A,ION = (R- 1/R) * φ Α,ΙΟΝ φ INST Anything! MulX- channel KVN receivers

4 Frequency Phase Referencing (FPT) (Also referred to as MulL Frequency Phase Referencing, MFPR) OUTCOME: PRECISE CALIBRATION OF THE TROPOSHERE (and in general any non- dispersive residuals) ENABLES: EXTEND COHERENCE TIME è è WEAK SOURCE DETECTION AT HIGH FREQUENCIES ASTROMETRY * SIMULTANEOUS mul0- frequency observa0ons required for high freqs.

5 Source Frequency Phase Referencing (SFPR) Rioja & Dodson 2008,2011 WEAK SOURCES ASTROMETRY Target Source A Several deg. _ BETTER SIMULTANEOUS! HIGHER FREQUENCIES OK Reference Source B C T Several Minutes R = ν / ν Fast Slow Slow φ FPT Α = φ A,GEO + φ A,TRO + φ Α,ΙΟΝ + φ Α,ΙΝST +φ A,STR + 2πn A φ A- B SFPR φ FPT Β = φ B,GEO + φ B,TRO + φ Β,ΙΟΝ + φ Β,ΙΝST +φ B,STR + 2πn B φ A,ION - φ B,ION = 0 φ A,INST - φ A,INST = 0 (TWO SOURCES) Lme KVN Astrometry: FFT φ A- B SFPR SFPRed A- Map at high freq.

6 Source Frequency Phase Referencing (SFPR) WEAK SOURCES ASTROMETRY Target Source A Several deg. SFPR: Rioja & Dodson 2008,2011 BETTER SIMULTANEOUS! (TWO SOURCES) HIGHER FREQUENCIES OK Reference Source B C T R = ν / ν Fast Slow Slow φ FPT Α = φ A,GEO + φ A,TRO + φ Α,ΙΟΝ + φ Α,ΙΝST +φ A,STR + 2πn A φ A- B SFPR φ FPT Β = φ B,GEO + φ B,TRO + φ Β,ΙΟΝ + φ Β,ΙΝST +φ B,STR + 2πn B φ A,ION - φ B,ION = 0 φ A,INST - φ A,INST = 0 KVN Astrometry: FFT φ A- B SFPR SFPRed A- Map at high freq.

7 Source Frequency Phase Referencing (SFPR) OUTCOME: PRECISE ATMOSPHERIC & INSTR. CALIBRATION, WHILE KEEPING ASTROMETRIC SIGNATURE ENABLES: EXTEND COHERENCE TIME & ASTROMETRY è è WEAK SOURCE DETECTION AT HIGH FREQUENCIES ASTROMETRY (frequency dependent source posixon: conxnuum & lines) *Slow antenna switching OK *Several degrees source separaxon OK * SIMULTANEOUS mul0- frequency observa0ons required for high freqs.

8 Demonstration: 4-band KVN SFPR observations of 5 AGNs Triangle 1 Triangle 2 2 o ,43,86,129 GHz

9 Demonstration: 4-band KVN SFPR observations of 5 AGNs Triangle 1 Triangle 2 2 o 11 o 8.6 o 22,43,86,129 GHz o

10 Demonstration: 4-band KVN SFPR observations of 5 AGNs o Triangle 1 Triangle 2 2 o 6.7 o 4.5 o 11 o 8.6 o 22,44,88,132 GHz KVN Obs.: DuraLon 8 hours 3 min scan/source o

11 Demonstration: 4-band KVN SFPR observations of 5 AGNs o 6.7 o Triangle 1 Triangle 2 2 o 4.5 o 11 o 8.6 o 22,44,88,132 GHz KVN Obs.: DuraLon 8 hours 3 min scan/source 3.6 o

12 Demonstration: 4-band KVN SFPR observations of 5 AGNs (1) Outcomes: EffecLve Tropospheric CompensaLon FPT analysis 2-frequencies

13 22 GHz, raw FPT analysis 44 GHz, raw 2- frequencies Residuals increase with R, for a given ν low (22GHz) FPT: 22à 44, x2

14 22 GHz, raw FPT analysis 44 GHz, raw 2- frequencies 88 GHz, raw Residuals increase with R, for a given ν low (22GHz) FPT:22à 44, x2 FPT:22à 88, x4

15 22 GHz, raw FPT analysis 44 GHz, raw 2- frequencies 88 GHz, raw 132 GHz, raw Residuals increase with R, for a given ν low (22GHz) FPT analysis residuals increase with R, for a given nu_low (22GHz) FPT:22à 44, x2 FPT:22à 88, x4 FPT:22à 132, x6

16 FPT analysis 2- frequencies Residuals increase with R, for a given ν low (44 GHz) FPT:44à 88, x2 FPT:44à 132, x3

17 FPT analysis 2- frequencies Residuals increase with R, for a given ν low (44 GHz) FPT:44à 88, x2 FPT:44à 132, x3 Dispersive Terms non-zero, preventing imaging, but not fast changing _ φ Α FPT R = ν / ν Fast Slow Slow φιον + φ + ΙΝST φ Α = φ A,GEO + φ A,TRO + φ Α,ΙΟΝ + φ Α,ΙΝST +φ A,STR + 2πn A φ Α = φ Α,GEO A,TRO Α,ΙΟΝ Α,ΙΝST 2πn R*φ A Α = R*(φ Α,GEO + φ A,TRO + φ Α,ΙΟΝ + φ Α,ΙΝST + 2πn A )

18 Demonstration: 4-band KVN SFPR observations of 5 AGNs (1) Outcomes: EffecLve Troposheric CompensaLon FPT analysis 2-frequencies (2) Outcomes: Astrometry SFPR analysis 2-frequencies & 2 sources

19 SFPR analysis 132 GHz with 43GHz: (ref. 6.3 o away) A) , FPT, 44à 132, x3 A) SFPR, 132 GHz A) B) B) ref.,fpt, 44à 132, x3 A) SFPRed Map at 132 GHz FFT Bona- fide Astrometry Shil ~ (- 50,+50) µas Peak Flux ~ 150 mjy rms ~ 5mJy/beam 85-90% Flux Recovery

20 SFPR analysis 132 GHz with 43GHz: (ref. 6.3 o away) A) , FPT, 44à 132, x3 A) SFPR, 132 GHz A) B) B) ref.,fpt, 44à 132, x3 A) SFPRed Map at 132 GHz FFT Bona- fide Astrometry Shil ~ (- 50,+50) µas Peak Flux ~ 150 mjy rms ~ 5mJy/beam 85-90% Flux Recovery

21 SFPR analysis 132 GHz with 43GHz: (ref. 11 o away) A) FPT,44à 132, x3 A) SFPR 132 GHz A) B) B) ref., FPT,44à 132, x3 A) SFPRed Map at 132 GHz FFT Peak Flux ~ 100 mjy rms ~ 5 mjy/beam 87% Flux Recovery Bona- fide Astrometry Shil ~ (- 221,+150) µas

22 SFPR analysis 132 GHz with 43GHz: (ref. 11 o away) A) FPT,44à 132, x3 A) SFPR 132 GHz A) B) B) ref., FPT,44à 132, x3 A) SFPRed Map at 132 GHz FFT Peak Flux ~ 100 mjy rms ~ 5 mjy/beam 87% Flux Recovery Bona- fide Astrometry Shil ~ (- 221,+150) µas

23 SFPR Astrometric RELATIVE Measurements: between TWO frequencies & TWO sources Red- KQ Blue KW Black KD Green QW Cyan QD

24 Demonstration: 4-band KVN SFPR observations of 5 AGNs (1) Outcomes: EffecLve Tropospheric CompensaLon FPT analysis 2-frequencies (2) Outcomes: Astrometry SFPR analysis 2-frequencies & 2 sources (3) Outcomes: Increased Coherence Time FPT & SFPR analysis

25 Demonstration: Coherence Studies % Peak Flux Recovery 60% 20min 8 hours Time (minutes) Freq.Pair Analysis EffecXve Coherence Time 44à 132 GHz FPT (or MFPR) 20 min 44à 132 GHz SFPR (*11deg) > 8 hours

26 è NEW: From Relative to Individual Source Shifts: Single Value Decomposition Method ν low à ν high θ PosiLon shi] 1,2,3,4,5 sources [A- B] = [M] x [S] SVD [S] Degenerate SoluLon θ 12 θ 13 θ 23 θ 14 θ 15 θ 45 Astrometric Relative Measurements Source Pair Matrix θ 1 θ 2 θ 3 θ 4 θ 5 Individual Source Shifts

27 Individual Source Shifts: Single Value Decomposition Method Red KQ Blue KW Cyan KD Green QW Black QD Degenerate SoluLon Jet DirecXons

28 Jet DirecLons In the maps: RA RA In the plots:

29 Constraint: Jet DirecLons Independent analysis per frequency pair PLOT: Unique common shi] (x=ra,y=dec) for all 5 sources, and combined (all- source Misalignment with corresponding Jet DirecLons (z=error). More sources and wider distribulon of PAs sets stronger constraints.

30 Individual Source Shifts: Single Value Decomposition Method PLUS Jet Direction Constraint Non- Degenerate SoluLon Red KQ Blue KW Cyan KD Green QW Black QD Jet DirecXons 1803,

31 Individual Source Shifts: Single Value Decomposition Method PLUS Jet Direction Constraint Non- Degenerate SoluLon Red KQ Blue KW Cyan KD Green QW Black QD Jet DirecXons 1803,

32 Astrophysical Applications Any field that requires mm- wave: 1) bona- fide astrometric image alignment at different frequencies, and/or 2) increased sensixvity. SpaLal registralons of molecular emission in Evolved Stars and SFRs (see talk by Yun Youngjoo; poster by Yoon Dong- Hwan et al., H 2 O and SiO) AGN Core- Shi]s at mm- waves: transilon from BK model to shock. Spectral Index and RotaLon Measure Maps. With mullple bands, one can measure the Spectral Energy DistribuLon and perform Faraday Tomography. 32

33 Summary Bona- fide Astrometric Measurements between 5 AGNs at 132 GHz. DemonstraXon of capabilixes with KVN observaxons up to 132 GHz. Made possible by the SFPR method à high precision astrometry with mm- VLBI, for conxnuum & spectral line. A path for disentangling the measurements into the frequency dependent posixon shils for the individual sources. This is the basis for any study that requires alignment of mm- VLBI images at different frequencies.