Source-Frequency Phase-Referencing Observation of AGNs with KaVA Using Simultaneous Dual-Frequency Receiving.

The KVN(Korean VLBI Network)-style simultaneous multi-frequency receiving mode is demonstrated to be promising for mm-VLBI observations. Recently, other Very long baseline interferometry (VLBI) facilities all over the globe start to implement compatible optics systems. Simultaneous dual/multi-frequency VLBI observations at mm wavelengths with international baselines are thus possible. In this paper, we present the results from the first successful simultaneous 22/43 GHz dual-frequency observation with KaVA(KVN and VERA array), including images and astrometric results. Our analysis shows that the newly implemented simultaneous receiving system has brought a significant extension of the coherence time of the 43 GHz visibility phases along the international baselines. The astrometric results obtained with KaVA are consistent with those obtained with the independent analysis of the KVN data. Our results thus confirm the good performance of the simultaneous receiving systems for the non-KVN stations. Future simultaneous observations with more global stations bring even higher sensitivity and micro-arcsecond level astrometric measurements of the targets.

[1]  Sang-Sung Lee,et al.  VLBI observations of bright AGN jets with the KVN and VERA Array (KaVA) : Evaluation of imaging capability (Special Feature : Recent Results from VERA) , 2014 .

[2]  Maria Rioja,et al.  Kvn Source-Frequency Phase-Referencing Observation of 3c 66A and 3c 66B , 2015 .

[3]  Do-Young Byun,et al.  Korean VLBI Network Receiver Optics for Simultaneous Multifrequency Observation: Evaluation , 2013 .

[4]  Sang-Sung Lee,et al.  Relativistic Jets as Compact Radio Sources , 2014 .

[5]  Noriyuki Kawaguchi,et al.  VLBI Imaging of M81* at λ = 3.4 mm with Source-frequency Phase-referencing , 2018, 1801.04571.

[6]  Mareki Honma,et al.  MEASURING THE CORE SHIFT EFFECT IN AGN JETS WITH THE EXTENDED KOREAN VLBI NETWORK , 2015 .

[7]  Richard Dodson,et al.  THE POWER OF SIMULTANEOUS MULTIFREQUENCY OBSERVATIONS FOR mm-VLBI: ASTROMETRY UP TO 130 GHz WITH THE KVN , 2015, 1509.02621.

[8]  S. Tingay,et al.  THE IMPACT OF FREQUENCY STANDARDS ON COHERENCE IN VLBI AT THE HIGHEST FREQUENCIES , 2012, 1209.3989.

[9]  Min-Gyu Song,et al.  ASTROMETRICALLY REGISTERED SIMULTANEOUS OBSERVATIONS OF THE 22 GHz H2O AND 43 GHz SiO MASERS TOWARD R LEONIS MINORIS USING KVN AND SOURCE/FREQUENCY PHASE REFERENCING , 2014, 1408.3513.

[10]  Do-Young Byun,et al.  INTERFEROMETRIC MONITORING OF GAMMA–RAY BRIGHT ACTIVE GALACTIC NUCLEI II: FREQUENCY PHASE TRANSFER , 2015, 1510.05817.

[11]  Maria Rioja,et al.  Registration of H2O and SiO masers in the Calabash Nebula to confirm the planetary nebula paradigm , 2018 .

[12]  Richard Dodson,et al.  HIGH-PRECISION ASTROMETRIC MILLIMETER VERY LONG BASELINE INTERFEROMETRY USING A NEW METHOD FOR ATMOSPHERIC CALIBRATION , 2011, 1101.2051.

[13]  Tetsuo Sasao,et al.  First Simultaneous Dual-Frequency Phase Referencing VLBI Observation with VERA , 2011 .

[14]  Richard Dodson,et al.  The Science Case for Simultaneous mm-Wavelength Receivers in Radio Astronomy , 2017, 1709.07167.

[15]  K. I. Kellermann,et al.  MOJAVE. X. PARSEC-SCALE JET ORIENTATION VARIATIONS AND SUPERLUMINAL MOTION IN ACTIVE GALACTIC NUCLEI , 2013, 1308.2713.

[16]  Do-Young Byun,et al.  The Power of Simultaneous Multi-frequency Observations for mm-VLBI: Beyond Frequency Phase Transfer , 2017, 1712.06243.

[17]  Duk-Gyoo Roh,et al.  AMPLITUDE CORRECTION FACTORS OF KOREAN VLBI NETWORK OBSERVATIONS , 2015 .

[18]  Do-Young Byun,et al.  Astrometrically registered maps of H2O and SiO masers toward VX Sagittarii , 2018, Nature Communications.