8th KaVA Science WG Meeting

Transcription

1 2015 8th KaVA Science WG Meeting January 13 16, 2015 Gyeongju, Republic of Korea

2 General Information Venue: Daemyung Resort, Gyeongju, Republic of Korea Satellite meetings: January 13, 2015 KaVA Science WG Meeting: January 14 15, 2015 EB/DM: January 16, 2015 SOC Se-Hyung CHO (co-chair) Mareki HONMA (co-chair) Kee-Tae KIM Sang-Sung LEE LOC Yoon Kyung CHOI Hanui JEONG Jaeheon KIM Kee-Tae KIM (Chair) Mikyoung KIM Sena Kim Se-Jin OH Kiyoaki WAJIMA 2

3 SCHEDULE Tue. (13) Wed. (14) Thu. (15) Fri. (16) Registration 08:30 ~ 09:00 Opening 09:00 ~ 09:05 Status reports 09:05 ~ 10:50 SFR II 09:00 ~ 10:00 Coffee break 10:50 ~ 11:15 Coffee break 10:00 ~ 10:15 Astrometry 11:15 ~ 12:15 AGB I 10:15 ~ 12:00 Satellite Meeting Lunch 12:15 ~ 13:40 Lunch 12:00 ~ 13:30 EB/DM AGB 13:40 ~ 15:25 AGN II 13:30 ~ 14:35 Coffee break 15:25 ~ 15:50 Coffee break 14:35 ~ 15:00 SFR I 15:50 ~ 17:50 Large Proposals 15:00 ~ 17:00 Banquet 18:30 ~ 3

4 4 PROGRAM

5 The 1 st Day 01/14 Wed. 08:30 ~ 09:00 Registration Opening 09:00 ~ 09:05 Jongsoo Kim Welcome remark Status reports Chair: K. T. Kim 09:05 ~ 09:20 Do-Young Byun Operation report of KaVA 09:20 ~ 09:35 Tomoaki Oyama Report on the results of test broadband observations of VERA 09:35 ~ 09:50 Osamu Kameya Activity of the Mizusawa 10m radio telescope and pulsar observations using VERA 09:50 ~ 10:05 Yoshiaki Hagiwara Recent status of EAVN experiments 10:05 ~ 10:20 Noriyuki Kawaguchi Controversial issues on the KaVA and EAVN sensitivity calibration 10:20 ~ 10:35 Se-Jin Oh Recent status of KJCC 10:35 ~ 10:50 Discussion 10:50 ~ 11:15 Coffee break Astrometry Chair: S. -H. Cho 11:15 ~ 11:30 Nobuyuki Sakai Activity and future of the galactic astrometry sub-wg 11:30 ~ 11:45 Taehyun Jung KaVA system for high precision astrometry : present evaluation and perspectives 11:45 ~ 12:00 Taehyun Jung Results of phase referencing observations with KVN and KaVA 12:00 ~ 12:15 Discussion 12:15 ~ 13:40 Lunch AGB Chair: H. Imai 13:40 ~ 13:55 Yoshiharu Asaki KaVA observations for two red supergiants 13:55 ~ 14:10 Youngjoo Yun Simultaneous observations of the H 2 O and SiO masers around the late-type stars using KVN 14:10 ~ 14:25 Yoon Kyung Choi The calibrator search for evolved stars with the KVN 14:25 ~ 14:40 Cheulhong Min A long-period observations of SiO masers toward a symbiotic star R Aquarii 14:40 ~ 14:55 Se-Hyung Cho Time monitoring observations toward TX Cam using the KVN single dish 14:55 ~ 15:10 Yuanwei Wu AGB candidates from WISE and AKARI 15:10 ~ 15:25 Discussion 15:25 ~ 15:50 Coffee break SFR I Chair: D. -Y. Byun 15:50 ~ 16:05 Tomoya Hirota Status of SFRs sub-wg 16:05 ~ 16:20 Mikyung Kim Methanol maser observations towards G with KaVA and KVN 16:20 ~ 16:35 Naoko Matsumoto Imaging test of 44 GHz methanol maser with KaVA 16:35 ~ 16:50 Nagisa Shino Methanol maser observation of massive star formation region IRAS and IRAS

6 16:50 ~ 17:05 Koichiro Sugiyama Wide-field imaging of the 44 GHz methanol masers with KVN 17:05 ~ 17:20 Yong-Sun Park KVN absorption line observation toward galactic molecular clouds 17:20 ~ 17:35 Jeong-Sook Kim Transition of outflow morphology in the massive star forming region W75N 17:35 ~ 17:50 Discussion 18:30 ~ Banquet The 2 nd Day 01/15 Thu. SFR II Chair: T. Hirota 09:00 ~ 09:15 Kazuyoshi Sunada VERA single dish mode surveys of new maser sources 09:15 ~ 09:30 Koichiro Sugiyama Methanol maser survey at 6.7 GHz with Hitachi 32-m toward BGPS dust core sources 09:30 ~ 09:45 Chang-Hee Kim A maser survey towards massive YSOs from RMS 09:45 ~ 10:00 Discussion 10:00 ~ 10:15 Coffee break AGN I Chair: M. Kino 10:15 ~ 10:30 Guang-Yao Zhao KaVA Q-band observation of Sgr A* 10:30 ~ 10:45 Atsushi Miyazaki Intra-day variability of Sgr A* by the KVN multi-frequencies observations 10:45 ~ 11:00 Fumie Tazaki Super-resolved image of M87 with sparse modeling 11:00 ~ 11:15 Jiang Wu Position angle changes of the M81 jet in time and frequency 11:15 ~ 11:30 Bong Won Sohn KVN/KaVA AGN polarimetry 11:30 ~ 11:45 Jae-Young Kim A study on plasma-physical properties of jets in nearby AGN with KVN and KaVA 11:45 ~ 12:05 Discussion 12:05 ~ 13:40 Lunch AGN II Chair: B. W. Sohn 13:40 ~ 13:55 Kiyoaki Wajima Multi-frequency phase-referencing observations of a Gigahertzpeaked spectrum source PKS :55 ~ 14:10 Satoko Sawada-Sato HCN and HCO + absorptions on NGC :10 ~ 14:25 Jeong Ae Lee KVN Calibrator Survey (KVNCS): 2. K -band fringe survey 14:25 ~ 14:40 Discussion 14:40 ~ 15:00 Coffee break Large Proposals 15:00 ~ 15:25 Hiroshi Imai KaVA ESTEMA 15:25 ~ 15:50 Tomoya Hirota KaVA SFR large proposal 15:50 ~ 16:15 Motoki Kino AGN large project with KaVA 16:15 ~ 17:00 Discussion Chair: M. Honma 6

7 7 ABSTRACTS

8 Operation report of KaVA Do-Young Byun KASI I will present the operation report of KaVA. Report on the results of test broadband observations of VERA Tomoaki Oyama NAOJ 8

9 Activity of the Mizusawa 10m radio telescope and Pulsar observations using VERA Osamu Kameya NAOJ Daily VLBI monitor observations at 22GHz using the Mizusawa 10m radio telescope was conducted toward Sgr A* for one and half year. Some results are shown and explained. This year there were chances to conduct single dish pulsar test observations at S band and C band using the VERA Mizusawa station. Some preliminary results are shown. Recent status of EAVN experiments Yoshiaki Hagiwara NAOJ Many efforts have been made since 2013 to construct a VLBI network in east Asia by linking telescopes in China, Japan, and Korea. In this talk, recent results of EAVN fringe test observations will be reported and also future prospects are presented. 9

10 Controversial issues on the KaVA and EAVN sensitivity calibration Noriyuki Kawaguchi SHAO I received a calibration log file obtained in Yonsei station of KVN. In the analysis of the data, I found big difference in the way of sensitivity calibration between KVN and VERA. I will point out the problems of the calibrations on both ways of VERA and KVN and present a new unified scheme of the sensitivity calibration in the future KaVA and EAVN observation for more reliable scientific outputs. Recent status of KJCC Se-Jin Oh KASI Daejeon correlator for East Asian VLBI Network is normally operated in close cooperation with KVN and VERA since From 2014B, the media for observation is changed to HDDs in each site. So the correlation processing time is reduced and also media release period is faster than previous. In this presentation, recent correlation status for KaVA observation in 2014 will be reported and future plan will be presented. 10

11 Activity and future of the galactic astrometry sub-wg Nobuyuki Sakai NAOJ We will report current progress and future plan of the Galactic Astrometry sub-wg. To evaluate repeatability and position accuracy of KaVA astrometry, we conducted four astrometry observations in 2012, of which two were correlated with Mitaka FX correlator. At this meeting, we will report current progress of the two data reductions. To routinely conduct KaVA astrometry, we have listed technical issues such as station positions, troposphere and ionosphere corrections, and re-calibration of a delay model used in a correlator (called as uvw-recalculation ). We will report how to treat each issue, and show future plan of our sub-wg. KaVA astrometry can expand scientific results of the all sub-wgs, and should be discussed in detail at this meeting. KaVA system for high precision astrometry: present evaluation and perspectives Taehyun Jung KASI VLBI astrometry is a unique method to measure the position or to identify radio emitting regions of radio sources. Achieving high precision astrometry in VLBI requires stringent constraints, such as high stability system and an appropriate observing strategy including proper calibration methods. In the preparation stage of KaVA astrometry, I will discuss current approaches and limitations of KaVA system including future prospects and emerging issues. 11

12 Results of phase referencing observations with KVN and KaVA Taehyun Jung KASI Phase referencing is an important technique to detect weak radio sources which are usually faint in mmwavelength or to obtain astrometric information. In order to evaluate the phase referencing capability of KVN and KaVA, several test observations have been conducted and analyzed. In this talk, I will present the results of (1) KVN phase referencing test (conventional phase referencing with multi-frequency observations) and (2) KaVA polar cap phase referencing test, and discuss some of the issues that arise during the observations and analysis. KaVA observations for two red supergiants Yoshiharu Asaki JAXA/ISAS We report on the recent status of the KaVA data reduction of two red supergiants (RSGs), PZ Cas and S Per. The 22 GHz water maser of PZ Cas was firstly observed using the KaVA in Because this object has been monitored with the VERA at 22 GHz, PZ Cas is a very suitable object for the KaVA commissioning and science verification by comparing with the previous VLBI images. In the previous study by Kusuno et al. (2013), the spatial distribution of the water masers had been stable for two years. We found that the spatial distribution revealed with the KaVA is very similar to those obtained by Kusuno et al. (2013), so that the water maser shell in the circumstellar envelop seems to be stable. Another target, S Per, has been observed three times in 2012, 2013, and 2014 at 22 GHz with the KaVA. The first two epoch images show that the spatial distribution of the water masers has not been changed dramatically since 2007 (Asaki et al. 2010). In the first epoch (2012), the KVN conducted simultaneous multi frequency observation at 22, 43, and 86 GHz. We successfully detected SiO masers of J=1-0, v=2 and 1. The multi frequency phase referencing with the KVN using the water maser fringe phase demonstrated successful phase calibration for the SiO masers. We also conducted the source frequency phase referencing for S Per using the 4-deg separated ICRF source, J , and successfully demonstrated to directly compare the positions of the water and SiO masers. SiO masers in the CSE of evolved stars are considered to be located within several stellar radii from the central star, so that the positions of S Per's SiO masers indicate the central star and the dynamical center of the maser proper motions. 12

13 Simultaneous observations of the H 2 O and SiO masers around the latetype stars using KVN Youngjoo Yun KASI We present the preliminary results of simultaneous observations of the H 2 O and SiO masers emitted from the circumstellar envelopes of the late-type stars. These observations has been carried out at the K and Q bands using KVN since Autumn in 2014 and were scheduled to test the feasibility of multi-frequency phase referencing analysis on the maser lines. In order to increase the accuracy of group delay solution in the fringe search on the continuum source, the IF channels were randomly distributed within the available bandwidth of 500 MHz in each band. The relative locations of the H 2 O maser spots with respect to the SiO maser spots are obtained from our results, and the capability of the simultaneous multi-band observation of KVN is proved to be powerful to study the maser pumping mechanism around the late-type stars. The calibrator search for evolved stars with the KVN Yoon Kyung Choi KASI We present results on calibrator search for sixteen evolved stars using the Korean VLBI Network (KVN). These evolved stars are selected for the Key Science Project (KSP) of the KVN. The KSP plans to investigate spatial structure and dynamical effect from SiO to H 2 O maser regions including mass-loss process and development of asymmetry in circumstellar envelopes of the evolved stars. For these, we need compact extragalactic sources close to the evolved stars. We carried out observations in order to detect radio continuum sources that can be used for phase-referencing. There is at least one continuum source for each evolved star and it enables us to try the source frequency phase referencing technique to superpose maps of H 2 O and SiO maser emission. 13

14 A long-period observation of SiO masers toward a symbiotic star R Aquarii Cheolhong Min NAOJ In this presentation, I will report preliminary results of SiO maser observations for a symbiotic binary star R Aquarii (R Aqr) with VERA from 2011 to Throughout observations, we found partial ring-like SiO maser distributions and different kinematic motions of different transitions of SiO maser shells possibly due to the shock propagations. This result probably provides constraints on the current dynamic models of innermost region of AGB atmosphere, and also implications for the second step of KaVA Large program for evolved star monitoring observations. Time monitoring observations toward TX Cam using the KVN single dish Se-Hyung Cho, Jaeheon Kim and Youngjoo Yun KASI Simultaneous time monitoring observations of H 2 O and SiO J = 1 0, 2 1, 3 2, and 29 SiO v = 0, J = 1 0 lines have been carried out toward about 40 evolved stars with the Korean VLBI Network single dish telescopes. Here we present the results of Mira variable star TX Cam as one of these monitoring results. For the first time, the H 2 O maser emission from TX Cam was detected near the stellar velocity at five epochs from April 10, 2013 (ϕ = 3.13) to June 4, 2014 (ϕ = 3.89) including minimum optical phases. The intensities of H 2 O masers are very weak compared with SiO masers. The variation of peak antenna temperature ratios among SiO v = 1, J = 1 0, J = 2 1, and J = 3 2 masers is investigated according to phases. The shift of peak velocities of H 2 O and SiO masers with respect to stellar velocity is also investigated according to observed optical phases. The H 2 O maser emission occurs around the stellar velocity during our monitoring interval. On the other hand, the peak velocities of SiO masers show a spread with respect to the stellar velocity. The peak velocities of SiO J = 2 1, and J = 3 2 masers show a small spread with respect to stellar velocity than those of SiO J= 1 0 masers. These simultaneous observations of multi-frequencies will provide a good constraint for maser pumping models and a good probe for investigating the stellar atmosphere and envelope according to their different excitation conditions. 14

15 AGB candidates from WISE and AKARI Yuanwei Wu NAOJ Right now, the largest published AGB catalog is from Suh+2013, with 3378 O-rich AGBs and 1168 C-rich AGBs. Within these O-rich AGBs, 67% of them are maser emitters, all of which are found by AGB maser surveys to samples selected from IRAS colors made in the past 30 years. In the past few years, new generation of infrared all-sky catalogues, i.e., WISE and AKARI, have released, with source numbers ~ 4 and 2000 times larger than IRAS. For instance, Ishihara+2011 have identified ~ O-rich AGB candidates from AKARI. Obviously, current AGB maser catalog is very incomplete. Follow up maser surveys based on AKARI and WISE data should be discussed and planned for next generation of maser studies of AGBs. Status of SFRs sub-wg We will report recent activities in the SFRs sub-wg. Tomoya Hirota NAOJ 15

16 Methanol maser observations towards G with KaVA and KVN Mikyoung Kim KASI We will present the result of the 44 GHz methanol maser observations towards G with KaVA and KVN. Imaging test of 44 GHz methanol maser with KaVA Naoko Matsumoto NAOJ I will report about imaging result of KaVA test data for four 44 GHz methanol maser based on the PET check list. 16

17 Methanol maser observation massive star formation region IRAS and IRAS Nagisa Shino SOKEDAI/NAOJ I report IRAS and IRAS where 44 GHz and 6.7 GHz methanol maser were detected. We made the space distribution map of a 6.7 GHz methanol maser and the 44 GHz methanol maser about IRAS GHz methanol maser and 44 GHz methanol maser are distributed over the same direction. So we think 6.7 GHz methanol maser may be excited by an outflow, too. Wide-field imaging of the 44 GHz methanol masers with KaVA Koichiro Sugiyama Ibaraki Univ. We made test observations for wide-field imaging of three methanol maser sources at 44 GHz with KaVA in Dec. 6 8th, So far, recorded data in VLBI observations have been normally correlated with integration time of 1 sec, which yields a field of view (FoV) of 4 arcsec at 44 GHz. The 44 GHz methanol masers, however, have shown spatial distributions spread over 10 arcsec in many sources. To confirm entire distributions and velocity structures of these masers, we need to conduct data correlations with integration time shorter than 1 sec. In this presentation, we will show a result of the test imaging observation in one of the target sources, G , correlated with integration time of 0.1 sec, yielding FoV of 40 arcsec at 44 GHz. 17

18 KVN absorption line observation toward Galactic molecular clouds Yong-Sun Park Seoul National Univ. In an attempt to probe the smallest scale structure of Galactic molecular clouds, we carried out absorption line observation in HCO+ toward radio quasars, NRAO150 and BL Lac. Since the radio quasars are extremely compact, the proper motion of intervening molecular clouds across the line of sight may result in the variation of the absorption line profile due to their internal structure. It is found that the HCO+ spectra of the two sources remain almost unchanged down to a few % level during 1998 to 2013, whereas it was claimed that the spectra changed during 1993 to Thus the profile variation noted in the past may be elusive probably due to poor S/N. Considering the significant profile variation of H 2 CO absorption line toward NRAO150 over the last twenty years, our observation suggests that we are witnessing chemical differentiation on the smallest scale ever. Transition of outflow morphology in the massive star-forming region W75N Jeong-Sook Kim and Soon-Wook Kim NAOJ and KASI One of the unsolved problems in astrophysics is how massive stars form and evolve. In the early stage of stellar evolution, the maser phenomena are caused by the interaction of outflows with interstellar medium. W75N is one of the representative massive star forming region with very bright H 2 O maser sources. VLA 1 and VLA 2, two maser sources sharing the same environment in W75N, have been displayed different H 2 O maser features: jet-like and wind-like outflows, respectively. In 2007 VERA observation, we found that the outflow of VLA2 has a transition from wind-like to jet-like outflow. Such transition and acceleration have never been explicitly observed in star-forming regions. We also show the acceleration of the outflow as a result of the transition. The result has been confirmed by further 2012 EVN observations. These results are consistent with a recent MHD simulation. I will discuss the 2007 VERA and 2012 EVN observations, and recent observation VERA. 18

19 VERA single dish mode surveys of new maser sources Kazuyoshi Sunada NAOJ I will report our activities of new maser survey. Methanol maser survey at 6.7 GHz with Hitachi 32-m toward BGPS dust core sources Koichiro Sugiyama Ibaraki Univ. We have initiated single-dish survey of the methanol masers at 6.7 GHz with Hitachi 32-m radio telescope since Nov. 3rd, The BGPS dust core sources could be good candidates for high-mass protostars (see Sunada-san's talk), and suitable targets to define the timing of appearances of the methanol masers at evolutionary phase in the high-mass star formation process. In this presentation, we will show progress of this single-dish survey for the 6.7 GHz methanol masers, which include some new detections. 19

20 A maser survey towards massive YSOs from RMS Chang-Hee Kim Seoul National Univ. / KASI We made simultaneous surveys of 22 GHz water and 44 / 95 GHz methanol masers toward 299 high-mass protostellar objects using the Korea VLBI Network (KVN) 21-m telescope. The sources were selected from the catalog of Red MSX Source (RMS) survey, which have bolometric luminosities > 103 L but are not associated with any radio continuum emission. We performed a simultaneous survey of 22 GHz water and 44 GHz methanol masers in 2011 and then conducted a simultaneous survey of 22 GHz water and 44 / 95 GHz methanol masers in The primary scientific goals of these surveys are to investigate the relationship among the three masers and to explore the relationship between each maser and the central star or the parental dense core. The detection rates of two epochs are 42% and 38% for water, 25% and 26% for 44 GHz methanol, and 23% (2012 only) for 95 GHz methanol masers. We performed a statistical analysis on subsample associated with a large data, i.e. ammonia, ATLASGAL and 6.7 GHz methanol survey. We proposed an evolutionary sequence for water and classi/ii methanol masers in high-mass star formation regions. KaVA Q-band observation of Sgr A* Guang-Yao Zhao KASI On behalf of the AGN sub-wg, I will report the data analysis results of KaVA Q band 1-Gbps observations of Sgr A*. KaVA has an excellent UV-coverage for Sgr A*, and with 256 MHz bandwidth, we achieved a image dynamic range higher than 300, which is more than 5 times better than previous VERA-only observations. This enables us to get more reliable size measurements, especially along the minor axis. With the future multi-epoch results, we will be able to study the variability of Sgr A* and put constrains on the emission mechanism. 20

21 Intra-day variability of Sgr A* by the KVN multi-frequency observations Atsushi Miyazaki KASI We are searching the time lag between the intra-day variabilities (IDVs) of Sagittarius A* (Sgr A*) in the 22, 43, 86, and 129 GHz bands using the KVN. For the Sgr A* IDV flare with timescale of a few hour, it was suggested that the flare emissions come from adiabatically expanding plasma blobs ejected close to the Galactic center black hole because of time lag detected between some frequencies. Because the KVN receiver system can observe in the multi-bands simultaneously, the KVN is very useful to detect the time lag. From the winter of 2013, we performed the KVN VLBI observations of Sgr A* in the multi-frequencies bands, and then the observations are going on now. We could not find the strong IDV flare feature synchronized at each band so far. The moderate IDVs less than about 20-30% were probably seen, but the significant time lag were not clear. I would like to report about the recent results of the KVN observations. Super-resolved image of M87 with sparse modeling Fumie Tazaki NAOJ We successfully reconstructed super-resolved images of M87 observed with VLBA, by using a new imaging technique of sparse modeling. The technique selects an optimum image with high sparsity (the most pixel values are zero). The angular-resolution was improved by a factor of ~ 3 compared with the synthesized beam size. We will show that the images have the obvious structure of limb brightening. 21

22 Position angle changes of the M81 jet in time and frequency Jiang Wu SHAO Observations of M81 were made in February, 2014 in Chinese VLBI network and correlated by the Sheshan DiFX correlator. In the data analysis, the pseudo closure relation was first applied and the position angle of the M81 jet was successfully detected. I will present briefly the observation and the data analysis and also show the importance of studies on the M81 jet by making multi-frequency VLBI observations by KaVA. KVN/KaVA AGN polarimetry Bong Won Sohn KASI We report the results of VLBI polarimetry tests and early scientific polarization observations of KVN and KaVA. KVN is fully operational in polarization mode at 22, and 129 GHz. VERA has 22 GHz polarization capability at Mizusawa and Iriki. Here we present KVN results at 22, 43 & 86 GHz and KaVA test result at 22GHz. 22

23 A study on plasma-physical properties of jets in nearby AGN with KVN and KaVA Jae-young Kim Seoul National Univ. Nearby bright Active Galactic Nuclei (AGN) are important sources to study relativistic jets of complex structure in detail. Improving physical understanding about launching, acceleration, and propagation of the structured outflows requires information on (i) internal conditions of plasma such as particle densities and degree of turbulence and (ii) the strength and geometry of magnetic fields pervading the jets. Multi-frequency VLBI observations especially with polarimetry have been crucial to spatially resolve the structures at different scales and to extract detailed information. Here, I show initial results from an ongoing plasma physics study of AGN, named as Plasma physics of Active Galactic Nuclei. The observed data show variety structures of the sources in total intensity, radio spectrum, and also in polarizations. Analyses based on both model component properties and 2D source maps are performed. In the presentation, I will especially talk about brightness temperature distributions of the sources and a relation between plasma opacity and degree of polarization for the jet components. Multi-frequency phase-referencing observations of a Gigahertz-peaked spectrum source PKS Kiyoaki Wajima KASI We made quasi-simultaneous multi-frequency VLBI observations of a gigahertz-peaked spectrum (GPS) radio galaxy PKS Observations were made with VERA at 22 and 43 GHz, and JVN at 8 GHz by employing phase-referencing technique. The source shows very peculiar, strongly frequency-dependent structure in parsec scale. In this presentation the details of our observation results and future scientific prospects by using KaVA will be given. 23

24 HCN and HCO + absorptions on NGC 1052 Satoko Sawada-Satoh NAOJ We present the preliminary result of KVN observations toward 88-GHz HCN and HCO + absorptions on the nearby radio galaxy NGC molecular KVN Calibrator Survey (KVNCS) : 2. K-band fringe survey Jeong Ae Lee KASI We have performed to find for VLBI fringes of the 556 candidates of VLBI phase calibrators at K band with Korean VLBI Network (KVN). The candidates were never observed at K band with VLBI systems. We had measured the single-dish flux densities of these sources from KVNCS1. We checked these sources have the single-dish flux densities greater than 200mJy. We obtained the fringes over 1 baseline from 446 of 556 sources. They had a quasi-uniform spatial distribution. According to the analysis of delay trend by time, we were able to check the uncertainties of their position by the position calibrators in KVN. In order to confirm as the VLBI phase calibrators, we should not only detect the fringes repeatedly and continuously, but also check the structure information. In the near future, we are going to carry out the VLBI imaging with KaVA. 24

25 KaVA ESTEMA Hiroshi Imai Kagoshima Univ. KaVA ESTEMA (Expanded Study on Stellar Masers) is a Large Project aiming to snapshot VLBI imaging of a large sample of circumstellar water and silicon-monoxide maser sources, followed by a decal intensive monitoring observation project for the masers with KaVA. The presentation will give a summary of the project, and propose ~200 hour KaVA machine time for mapping of the maser around approximately 80 stars. KaVA SFR large proposal We will present details of the KaVA large proposal from the SFRs sub-wg. Tomoya Hirota NAOJ AGN Large Project with KaVA In this talk, I summarize our proposal of Large Project for AGN observation with KaVA. Motoki Kino KASI 25

26 PARTICIPANTS 26

27 Last name First name Affiliation Algaba marco Juan Carlos KASI Asaki Yoshiharu JAXA(ISAS) Byun Do-Young KASI Cho Ilje UST / KASI ijcho@kasi.re.kr Cho Se-Hyung KASI cho@kasi.re.kr Choi Yoon Kyung KASI ykchoi@kasi.re.kr Hagiwara Yoshiaki NAOJ yoshiaki.hagiwara@nao.ac.jp Han Seog-Tae KASI sthan@kasi.re.kr Hirota Tomoya NAOJ tomoya.hirota@nao.ac.jp Honma Mareki NAOJ mareki.honma@nao.ac.jp Imai Hiroshi Kagoshima Univ. hiroimai@sci.kagoshima-u.ac.jp Jung Hanni KASI hanni0226@kasi.re.kr Jung Taehyun KASI thjung@kasi.re.kr Kameya Osamu NAOJ osamu.kameya@nao.ac.jp Kawaguchi Noriyuki SHAO kawaguchi@shao.ac.cn Kim Chang-Hee Seoul national Univ. / KASI chkim@kasi.re.kr Kim Dae-Won Seoul national Univ. dwkim@astro.snu.ac.kr Kim Jaeheon KASI jhkim@kasi.re.kr Kim Jae-Young Seoul national Univ. jykim@astro.snu.ac.kr Kim Jeong-sook NAOJ js.kim@nao.ac.jp Kim Jong-Soo KASI jskim@kasi.re.kr Kim Kee-Tae KASI ktkim@kasi.re.kkr Kim Mikyoung KASI mkkim@kasi.re.kr Kim Sena KASI Sena0712@kasi.re.kr Kino Motoki KASI kino@kasi.re.kr Kobayashi Hideyuki NAOJ hideyuki.kobayashi@nao.ac.jp Lee Taeseok Seoul national Univ. tlee@astro.snu.ac.kr Lee Jee Won Kyung Hee Univ. / KASI jwlee78@kasi.re.kr Lee Jeong Ae UST / KASI jalee@kasi.re.kr Liu Tie KASI liutiepku@gmail.com Matsumoto Naoko NAOJ naoko.matsumoto@nao.ac.jp Min Cheulhong GUAS / NAOJ cheulhong.min@nao.ac.jp Miyazaki Atsushi KASI amiya@kasi.re.kr Oh Chungsik KASI csoh@kasi.re.kr Oh Junghwan Seoul national Univ. joh@astro.snu.ac.kr Oh Se-Jin KASI sjoh@kasi.re.kr Oyama Tomoaki NAOJ t.oyama@nao.ac.jp Park Jong-Ho Seoul national Univ. jhpark@astro.snu.ac.kr Park Yong-Sun Seoul national Univ. yspark@astro.snu.ac.kr Roh Duk-Gyu KASI dgroh@kasi.re.kr Sakai Nobuyuki NAOJ nobuyuki.sakai@nao.ac.jp Sawada-Satoh Satoko NAOJ satoko.ss@nao.ac.jp Shibata Katsunori M. NAOJ k.m.shibata@nao.ac.jp Shin Jae Sik KASI jsshin@kasi.re.kr Shino Nagisa GUAS / NAOJ shino.nagisa@nao.ac.jp Sohn Bong Won KASI bwsohn@kasi.re.kr Sugiyama Koichiro Ibaraki Univ. koichiro@mx.ibaraki.ac.jp 27

28 Last name First name Affiliation Sunada Kazuyoshi NAOJ Tazaki Fumie NAOJ Trippe Sascha Seoul national Univ. Wajima Kiyoaki KASI Wu Yuanwei NAOJ Wu Jiang SHAO Yoon Dong-Hwan Seoul national Univ. / KASI dyyoon83@kasi.re.kr Yun Youngjoo KASI yjyun@kasi.re.kr Zhao Guang-Yao KASI gyzhao@kasi.re.kr 28