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I want to epress my joy for:

I want to epress my joy for:. -sharing with you guys this time in this beatiful planet. -sharing the excitement unveiling the secret live of the stars. -sharing the friendship with Peter who opened roads to the big scenario of massive stars. The Stellar Content of Galactic Giant HII Regions.

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I want to epress my joy for:

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  1. I want to epress my joy for: -sharing with you guys this time in this beatiful planet -sharing the excitement unveiling the secret live of the stars -sharing the friendship with Peter who opened roads to the big scenario of massive stars

  2. The Stellar Content of Galactic Giant HII Regions Augusto Damineli (IAGUSP) Robert Blum (NOAO) Peter Conti (JILA) Elysandra Figuerêdo (Open Un.) Alessandro Moisés (IAGUSP)

  3. Milky Way 2MASS Where are trhe arms? Longer wavelengths => clear view, but mixed structures Many methods indicate Sb-Sc types Mellinger‏

  4. (l,b) coordinates face-on map Rotation method RVs of radio recombination lines from HII regions + rotation curve => Distances to HII regions Clemens 1985

  5. Sun HII Regions Russeil 2003

  6. kinematic distances Limitations of the method: Radial velocities: - degenerate toward the GC line-of-sight - 2-valued r<R • Non-rotational components: - warm gas outflows from HII regions (10 Km/s - density-wave attractive force ( up to 10 km/s) - collisions between GMCs

  7. spectrophotometric distances Giant HII Regions Project started ~15 years ago by Conti, Hanson, Blum… -K-band imaging+spectra of ionizing O-type stars -Spectroscopic parallax: robust physics like in the optical window -Errors constrained by multiple stellar spectra

  8. Our Method: Giant HII Regions (NLyc=>1050 ph/s =>10 O7V*) good tracers of the spiral arms selected from radio and FIR surveys 50 imaged with Blanco/SOAR

  9. Colour- Magnitude Diagram: Candidates for spectroscopy foreground stars G333.1-0.4 ZAMS of the HIIR

  10. lines used to determine the spectral type Late O-type stars O6V O8V Spectral Type Distance Module DSpPt Spectroscopy of O-type stars: Hanson, Conti & Rieke (1996)

  11. Id Kdist kpc ref Sppdist kpc ref M8 2.8 R03 0.6 Bik04 W31 >4.1-12.3 C&E04 3.4 ± 0.5 BDC M17 2.4 R03 1.3 Hans97 W42 3.7 -11.5 R03 2.2 ±0.8 BCD W43 6.2 R03 5.9 ±0.7 BDC W49A 11.8 Wetal04 8.4 Bik04 W51A 5.5 R03 2.2 F07 W3OH 4.2 R03 1.95 Xu06 NGC3603* 7.9 R03 6.0 Stolte04 G282.0-1.2 G298.9-0.4 5.9 10.4 R03 5.3 ±1.2 3 F05 Bik04 G333.1-0.4 G331.5–0.1 3.5 10.8 R03 R03 2.4 ±0.4 4.5 ±0.3 F05 F05

  12. All shifts are toward smaller distances! Sun GC Conti & Crowther 2004

  13. Star Formation Rate in the Milky Way Conti & Crowther 2004 NLyC = 2.4 × 1052  ≥ 2.6 M/year Scaling the reduction to all sources NLyC = 1.7 × 1052  ≥ 1.8 M/year

  14. W3OH: emblematic for distance discrepancy Kin. distance d = 4.2 kpc (RV = -45 km/s) Russeil 2003 SpPht distance d = 2.2 kpc (optical) Humphreys 1978 Trig. VLBA OH masers d = 1.95±0.04 kpc Xu et al. 2006 Perseus arm is at wrong kinematic distance!

  15. spectrophotometric distances Limitations of the method: --Calibration uncertainty: MV = ± 0.7 Vacca et al. 1996 – Unresolved blends: 2 identical stars => Distance 40% smaller – Projected stars in the cluster line-of-sight What is the role of the reddening law? AK ~ 1/la Mathis (1990) a=1.7Nishiyama et al. (2006) a=1.99

  16. G353.19+0.64

  17. Ak=3 Ak=2 Ak=1

  18. Name DK DNish DMat kpc M8 2.8 0.9 0.8 W31 >4.1-12.3 3.9 3.3 M17 2.4 1.7 1.6 W42 3.7-11.5 2.8 2.5 W43 6.2 6.3 4.7 W49A 11.8 14.7 11.0 W51A 5.5 4.0 3.0 G298.2-0.3 10.4 4.6 3.9 G333.1-0.4 3.5 3.3 2.4 G331.5-0.1 10.8 5.5 4.5

  19. The slope of the luminosity function is independent of the Galactic ambient K-band LuminosityFunction --- NGC3576 --- G333.1-0.4  = 0.35  0.05 Salpeter In line with Massey 2003

  20. Morphologic Type of Milk Way L (H) [ergs/s]= ( 1.43 ×10-12 ) NLyC [photons/s] M17 W49A NGC3603 3GHIIR + luminous Conti & Crowther 2004 Kennicutt (1988)

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