Disk+outflow system in G

Transcription

1 EAVW PyeongChang Disk+outflow system in G Jungha Kim (D2/SOKENDAI/NAOJ) Tomoya Hirota, Kee-Tae Kim, KaVA SWG for star formation

2 CONTENTS Introduction Observations Results - KaVA imaging survey at 22 GHz - Case study toward G Future works

3 INTRODUCTION

4 HIGH-MASS STAR FORMATION (HMSF) Feedback!!

5 HIGH-MASS STAR FORMATION (HMSF) HMSF is still far from understanding OBSERVATIONALLY Locations are distant ( > 1 kpc) Typically occurred in clustered environments. Evolutional time scale is short ( 10 5 yrs). D=1.95 kpc (Xu+2006) limited. Targets are rare and LUCI JHKs color composite image of W3 Main (Bik+2012)

6 HIGH-MASS STAR FORMATION (HMSF) Evolutionary Sequence of high-mass young stellar objects (HMYSOs) Beltrán 2011 Observational studies to understand HMSF have been done.

7 DISK-OUTFLOW SYSTEM IN HIGH-MASS STAR FORMATION High velocity jets/outflows can be traced by resolving 1AU scale water maser structure to trace motion in milli arc second (mas)/month Large scale of view (disk+outflow) can be investigated by thermal The inner most part of jet/outflow line and continuum emission G Disk in ~ AU scale Beltran+2006 Massive disks and outflow

8 MOTIVATIONS To establish an evolutionary scenario using different maser species enlarge samples of HMYSOs having VLBI image To investigate dynamics of jet/outflow+disk systems driven by HMYSOs by analyzing 3D velocity field and spatial structure of water masers To reveal their launching and mass accretion processes

9 OBSERVATIONS

10 KaVA (KVN and VERA Array) Base line range: 200 km ~ 2300 km Observable bands: 22 GHz and 44 GHz The highest angular resolution: ~ GHz

11 OBSERVATIONS KVN single dish survey based target list KaVA LP 87 sources G KaVA LP 1st Methanol interesting sources ALMA 12 sources VERA 2 sources 25 sources Sources having no VLBI image but also famous VLBI sources to verify our observations 14 sources including G KaVA LP 2nd sources

12 RESULTS IMAGING SURVEY

13 SPECTRA OF WATER MASERS - EXAMPLES Systemic velocities Blue Red S255N AFGL5142 Blue and Red Blue only G v~3 km s -1 Red only G MM1 ~10 km s -1 G ~200 km s -1 Large velocity distribution ~40 km s -1

14 DISTRIBUTIONS OF WATER MASERS Two large trends in distributions of water masers 860 AU Elongated 1,220 AU Compact Each (0,0) is indicating position of the strongest water maser components

15 DISTRIBUTIONS OF WATER MASERS - EXAMPLES 356 AU 980 AU 1,660 AU 428 AU 600 AU 1,200 AU

16 RESULTS CASE STUDY

17 CASE STUDY - G G is one of high-mass star forming region. Detailed study toward this source has not been done yet. D~5.0 kpc Green & McClure-Griffiths ,000 AU Water maser spectrum at 22 GHz obtained with KaVA. Spatial distribution of water masers. (green: systemic velocity of 91 km s -1 ; shirley+2013)

18 CASE STUDY - G G is one of high-mass star forming region ,000 A compact distribution (within 0.15 x 0.15 arcsec) is shown with blue- and red shifted components. (first VLBI image)

19 G DISTRIBUTIONS Detected molecular line emissions show a compact shelllike structure with velocity gradient within the shell. Rotating disk Channel maps of CH3OH E M dust+gas = 97 M 5,000 AU +dust continuum peak The moment 1 map of CH3OH E (color) with the dust continuum emission (contours).

20 G OUTFLOWS/SiO Complicated distribution of outflowing gas Similar distribution is shown in 229 GHz Class I methanol maser map (not shown) + water maser 10,000 AU Blue: 90.2 km s -1 Red: 98.4 km s -1 Integrated intensity map of SiO 5-4 overlaid onto dust continuum

21 Outflow axes are inconsistent each other (SiO vs water maser) Measuring proper motion by monitoring observations is G OUTFLOWS - water masers * - class I methanol masers at 229 GHz + water maser 1,000 AU Another YSO? HM-YSO 10,000 AU Integrated intensity map of SiO 5-4 overlaid onto dust continuum emission Gray scale - dust continuum emission Contours - SiO outflow

22 FUTURE PROSPECTIVES - KAVA LP Monitoring observations using KaVA - In total, four epochs of observations in 2-3 months period will be done to measure proper motions of water masers toward 16 sources including G Two epochs of observations were already done. 3d velocity field will be investigated to define parameters of outflows such as inclination Monitoring observations using VERA - Positions of maser spots will be derived using phase referencing method

23 SUMMARY The first year project of water maser survey at 22 GHz using KaVA has been done. Both blue and red shifted components were apparently detected toward 16 sources among 21 detected sources. Monitoring observations toward 16 sources are in progress. Disk+outflow system is detected toward G by ALMA follow-up observations. Masses derived from molecular line and dust continuum suggest that G is potential a HM-YSO. Outflowing gas traced by SiO and Class I methanol maser presents complicated structure, suggesting multiple outflows. Analysis of monitoring observations with KaVA and VERA is in progress.