Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/research/masermeeting/web_papers/603_Honma.pdf Дата изменения: Fri Mar 23 04:35:39 2007 Дата индексирования: Sun Dec 23 09:45:39 2007 Кодировка: Поисковые слова: ultraviolet

Galactic rotation measurements based on water maser astrometry with VERA

Mareki Honma Mizusawa VERA observatory, NAOJ


Status of VERA in the last maser meeting
(Pictures presented at the Maser meeting in Brazil in March 2001)

Iriki

As of Feb. 2001

Mizusawa


VERA array now
Construction completed in 2002 Regular observations from 2004
Mizusawa

Iriki

Ishigaki-jima

All telescopes with dual-beam Max. baseline : 2300 km

Ogasawara


1. Astrometry of S269
S269 : Massive SFR toward anti-center (l=196 deg)

Near-IR view of S269 Jiang et al. (2003)

Maser spectrum and map with VERA


Parallax measurement
· Motions of S269 H2O maser with respect to J0613+1305 (0.7 deg separation)
East-West motion for 1 yr 1yr position 189 +/- 8 as D5.28 +0.24/-0.22 kpc North-South motion for 1 yr


S 269 proper motion
S269 motion with respect to LSR (V_l, V_b) = (-4.6, -4.1) km/s much smaller than galactic rotation (c.f. ~200 km/s) > similar galactic rotation velocity at the Sun and at S269
S269 Sun

Galaxy Center


Constraint on the rotation curve
For S269 at R=13.1 kpc, (13.1kpc) / 0 = 1.00 +/- 0.03
Rotation velocity (km/s)

N o da rk mat ter

Galacto-centric distance (kpc)

Flat rotation curve out to 13 kpc, plenty of dark matter


2. Proper motion of W49N
· W49Nnearly on the Solar circle Massive SFR at D ~ 11 kpc
HII regions with VLA

Line of sight

W49N

H2O maser with VERA

Solar circle

20000 AU


Proper motion of W49N
Motion of the brightest spot near systemic velocity from Oct. 2005 Oct. 2006 (with respect to J1905+0952)

Galactic Plane

Motion along the Galactic plane galactic rotation


LSR Angular Rotation Velocity
Preliminary results from 1-yr obs. = 6.5 +/- 0.1 mas/yr

(mas/yr)

Radial velocity measurements V_r= 9 +/-5 km/s They are consitent with =0/R0= 30.0 +/- 0.6 (km/s/kpc)

=31

W49N

=29 km/s/kpc

Second galaxy scale measurements next to Sgr A* c.f., Reid & Brunthaler (2004) = 29.45 +/- 0.1 (km/s/kpc), Sgr A* for 8 yr

Vr (km/s)


3. Other interesting results from VERA
Astrometry of nearby SFR Parallax of Orion-KL & NGC 1333
pi = 2.29 +/- 0.1 mas pi = 4.06 +/- 0.34 mas

Hirota, Poster 3-12


Masers in SFR
Detection of super-bubble motion ? (NGC 281 west)
galactic latitude

6.7GHz methanol maser map of Cep-A

10 deg

~20 km/s

galactic longitude

Sato, Poster 3-18

Sugiyama, Poster 3-20


Masers in AGB stars
Parallax of semi-regular variable S-Crt
Phase-referencing collocation of SiO v=1 and 2 at 43GHz in R-Aqr

pi = 2.3 +/- 0.2 mas Nakagawa, Poster 5-13 Kamohara, Poster 5-11


Conclusions
· We have successfully measured the parallax and proper motions of S269 at 5 kpc to constrain galactic rotation there. · Angular velocity of LSR is being constrained from proper motion of W49N --- these results demonstrate potential of VERA for exploring the Milky Way Galaxy And, more in posters !!