1 / 15

Proper motion of OH maser in G34.3+0.2

Proper motion of OH maser in G34.3+0.2. Li Guo, Xingwu Zheng, Bo Zhang, Xi Chen Shanghai Observatory, China Nanjing university, China kent-gl@shao.ac.cn. Outline. Introduction Observations and results Analysis Future work. Introduction.

dean-brock
Download Presentation

Proper motion of OH maser in G34.3+0.2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Proper motion of OH maser in G34.3+0.2 Li Guo, Xingwu Zheng, Bo Zhang, Xi Chen Shanghai Observatory, China Nanjing university, China kent-gl@shao.ac.cn

  2. Outline • Introduction • Observations and results • Analysis • Future work

  3. Introduction • OH masers probing the environments of high-mass star-forming regions (SFRs) • Bright >1Jy • Zeeman splitting, the magnetic field strength and line-of-sight directions • Linear polarization direction and fraction provides additional information about the 3D alignment of the magnetic field • Velocity field of many points around the central star-> using the velocity of emission of maser features.

  4. Introduction • G34.3+0.2 observations and theoretical models • Observations: radio continuum and atomic and molecular lines, 4 HII regions (components A B C D) found in the complex • 3 models: moving star bow shock model; champagne flow model; stellar wind model; high gas velocity • Low signal strength limits the resolution of observations of thermal emission so that those of the non-thermal maser emission may be useful

  5. Observation • 2 epochs of G34.3+0.2 • The first epoch • Time: 3 June, 1995, 5.5hrs on source • Sites: NRAO VLBA 10 antennas • Freq : 1665MHz 1667MHz • Polarization: LCP RCP • 250kHz pass-band centered on Vlsr=60km/s • Array phase center a2000 = 18h 53m 18.651s, d2000 = 01°14’ 58.08 • 256 spectral channels -> velocity spacing of 0.176km/s • Phase reference : LSR velocity 58.8km/s in 1667MHz RCP

  6. Observation • The second epoch • Time: 1 Feb, 2001, 4.2hrs on source • Sites: NRAO VLBA 10 antennas • Freq : 1665MHz 1667MHz • Polarization: LCP RCP • 125kHz pass-band centered on Vlsr=58km/s • Array phase center a2000 = 18h 53m 18.67s, d2000 = 01°14’ 58.85 , • 128 spectral channels -> velocity spacing of 0.176km/s • Phase reference : LSR velocity 58.8km/s in 1667MHz RCP

  7. Data processing • RR LL auto-polarization mode Socorro, New Mexico • Parallatic angle, amplitude corrections • Fringe rates, delay and Doppler shift corrections • Fringe fitting of the phase reference to determine the residual fringe rate • Calibrated visibilities were Fourier transformed and de-convolved using IMAGR with cell-size 3*6 mas

  8. Results • All OH maser features of the first epoch, 120 maser spots in all

  9. moving star bow shock model

  10. Results • Epoch1:49 maser spots; Epoch 2:39

  11. Results • 25 maser features are conformed for proper motions • The averaged proper motion • +0.99mas/yr in R.A. • -1.87mas/yr in DEL

  12. Results

  13. Analysis • About 40 OH maser spots have been found in the cluster near the apex • All OH maser spots are found to be well aligned along the ionization front • Distributions of all maser spots and proper motion of maser spots near the apex maybe show the consistency with the moving star bow shock model • More detailed work

  14. Future work • Proper motions of All the OH maser spots will be calculated soon

  15. Thanks for your attentions!

More Related