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

Augusto Damineli (IAGUSP)

Robert Blum (NOAO)

Peter Conti (JILA)

Elysandra Figuerêdo (Open Un.)

Alessandro Moisés (IAGUSP)

The Stellar Content of Galactic Giant HII Regions

MellingerMellinger2MASS2MASS

Many methods indicate Sb-Sc types

Where are trhe arms? Longer wavelengths => clear view, but mixed structures

RVs of radio recombination lines from HII regions => Distances to HII regions + rotation curve

face-on map

(l,b) coordinates

Clemens 1985

SunHII RegionsRusseil 2003

Radial velocities: - degenerate toward the GC line-of-sight

- 2-valued r<R

Limitations of the method:

Non-rotational components: - warm gas outflows from HII regions (10 Km/s - density-wave attractive force ( up to 10 km/s) - collisions between GMCs

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

Giant HII Regions

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

Colour- Magnitude Diagram:

foreground stars

ZAMS of the HIIR

Candidates for spectroscopy

Spectroscopy of O-type stars:

Distance Module

DSpPtHanson, Conti & Rieke (1996)

Spectral Type

O6V O8V

Late O-type stars

lines used to determine the spectral type

Id Kdist

kpcref Sppdist

kpcref 

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

G282.0-1.2G298.9-0.4

5.910.4 R03

5.3 ±1.23

F05Bik04

G333.1-0.4G331.5–0.1

3.510.8

R03R03

2.4 ±0.44.5 ±0.3

F05F05

All shifts are toward smaller distances!

Conti & Crowther 2004

Sun

GC

Star Formation Rate in the Milky Way

Scaling the reduction to all sources

NLyC = 1.7 × 1052 ≥ 1.8 M/year

Conti & Crowther 2004NLyC = 2.4 × 1052 ≥ 2.6

M/year

Trig. VLBA OH masers d = 1.95±0.04 kpc Xu et al. 2006

SpPht distance d = 2.2 kpc (optical) Humphreys 1978

W3OH: emblematic for distance discrepancy

Perseus arm is at wrong kinematic distance!

Kin. distance d = 4.2 kpc (RV = -45 km/s) Russeil 2003

What is the role of the reddening law?

AK ~ 1/

Mathis (1990) =1.7 Nishiyama et al. (2006) =1.99

--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

Limitations of the method:

G353.19+0.64

Ak=1

Ak=2

Ak=3

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

--- NGC3576

The slope of the luminosity function is independent of the Galactic ambient

= 0.35 0.05

K-band Luminosity

Function

--- G333.1-0.4

SalpeterIn line with Massey 2003

L (H) [ergs/s]= ( 1.43 ×10-12 ) NLyC [photons/s]

Conti & Crowther 2004

3GHIIR + luminous

M17

W49A

NGC3603

Morphologic Type of Milk Way

Kennicutt (1988)