RSGC crowd Ricardo Dorda, Amparo Marco Universidad de Alicante , Spain Carlos González-Fernández CASU, Cambridge , UK Wd1 crowd J. Simon Clark, Ben W. Ritchie Open University , UK Paul A. Crowther, Simon Goodwin Shefeld , UK Francisco Najarro CAB–CSIC, Spain Massive clusters in the Ignacio Negueruela Gainesville, April 2016

What are we calling a young massive cluster?

Definition of “massive” depends on context

In the Milky Way, ( Focuswe go Meeting for initial at mass the Beijing 4 Mcl ≥ 10 M⊙ IAU GA, 2013 )

An astrophysical laboratory on its ownFiger - cf. 2005 upperCrowther+ limit to the 2010 stellar mass (Arches, ; , ; talk by Caballero-Nieves)

VdBH 222

23 d Cepheid RSGs

Blue giants

Age ~18 Ma Distance 6 kpc 4 Mass ~2x10 M⊙

V

AvLSR≈= ­100 7.5 ±3 km/s ℓ = Marco et al. 2014; A&A 567, A73 349° Distribution of young massive clusters in the Milky Way

Cygnus

Mercer 81 Center Arches Quintuplet Mercer 30 Norma RSG1 Stephenson2Scutum RSGC3 Alicante 10 Crux Alicante 7 Westerlund 1 NGC 3603 Sagitarius Carina Masgomas-1 Tr14+16 Westerlund 2

Orion Perseus Young massive clusters

” Even if these (LMC) clusters are not quite as spectacular as those found in genuine starburst , they are still more massive than any of the open clusters seen in the Milky Way today” Larsen & Richtler 1999, A&A 345, 59

Spiral starburst NGC 3310 The young globular NGC 1850, in the LMC The young globular NGC 1755, in the LMC (HST image from Wikipedia) M 11

The intermediate- age cluster M11, in the Milky Way (ESO/WFI) M 11

McNamara & Sanders (1977) A&A 54, 569

Star counts: 2900 M⊙ Virial: 6000 M⊙

Bruch & Sanders (1983) A&A 121, 237

e.g. NGC 663: 800 M⊙

Battinelli & Capuzzo-DolcettaSee also (1991, MNRAS 249, 76) The young cluster NGC 663, in the Milky Way (Michael Siniscalchi @ helixgate.net) Bruch & Sanders (1983) A&A 121, 237

e.g. NGC 663: 800 M⊙

… moreMarco like et el.,4000 in prep.M⊙

The young cluster NGC 663, in the Milky Way (Michael Siniscalchi @ helixgate.net) Distribution of young massive clusters in the Milky Way

Cygnus

Mercer 81 Center Arches Quintuplet Mercer 30 Norma RSG1 Stephenson2Scutum RSGC3 Alicante 10 Crux Alicante 7 Westerlund 1 NGC 3603 Sagitarius Carina Masgomas-1 Tr14+16 Westerlund 2

Orion Perseus

NGC 654

NGC 663, the core of CasOB8

90’ = 65 pc @ 2.5 kpc NGC 659

Alicante 9 – cluster candidate Negueruela et al. (2011)

Alicante 7 – cluster RSGC3 – big cluster Negueruela et al. (2011) Clark et al. (2009)

30’ = 52 pc @ 6 kpc

Glimpse 360 view towards l = 29°, b =0° Alicante 10 – pretty big cluster González-Fernández & Negueruela (2012) Westerlund 1 is the most massive young so far known in the Milky Way.

At least 150 evolved massive ( ) observed imply ⊙ M > 30 M 5 (Clark et al. 2005, A&A M 434,≈ 10 949M)⊙

Star counts in the IR imply (Gennaro et

4 al. 2011, M MNRAS ≥ 5x10 412,M ⊙2469; talks by Lu & Andersen)

5Myr Age Ma d ~ 4 kpc ≈ 4 6.3 Myr V

A ≈ 10 6.3Myr with high rotation Gennaro et al. 2011, MNRAS 412, 2469

Negueruela et al. 2010, A&A, 516, A78 Old Geneva tracks

Age Ma d ~ 6 kpc≿ 5

V A ≈ 12 This is not isolated case! PMS tracks always give younger ages 5Myr

6.3 Myr

Naylor 2009, MNRAS 399, 432 6.3Myr with high rotation Bell et al. 2012, MNRAS 424, 3178

Negueruela et al. 2010, A&A, 516, A78 Old Geneva tracks

Age Ma d ~ 6 kpc≿ 5

V A ≈ 12 This is a 9.2-d (almost- Wd1-13 detached) eclipsing binary (Bonanos 2007, AJ 133, 2696)

Dynamical determination Evidence for two separate indicates both members had evolutionary channels for massive initial , likely 4 stars ( ): (RitchieM et⭑ >al. 30 2010,M⊙ A&A 520,0 A48M⊙) Single @40M O→BSG⨀ →YHG→RSG→WR Another member with 4 Binary O→BHG/LBV→WR (Koumpia & Bonanos 2012, A&A 547, A30) M⭑ ≈ 0 M⊙ FLAMES spectroscopic survey

≥ 40% of observed stars are binaries. Most (all?) WR stars are binaries.

W43a (B0 Ia ) Porb = 16.3 days

Ritchie et al. 2009, A&A 507, 1597 Ritchie et al. 2011, BSRSL 80, 628 Clark et al. 2011, A&A 531, A28 W239 (WC9d) Porb = 5.1 days A real velocity dispersion

No evidence for dynamically separate subclusters

Radial velocities for Wd1 members, corrected for binarity and pulsation vsys= -42.9±4.6 km/s (Clark et al., in preparation) Field centred on Westerlund 1

(Negueruela et al., in preparation)

Kothes & Dougherty (2007, A&A 468, 993)

Westerlund 1 is completely isolated!

Summary

4 There is a significant population of massive (Mcl >10 M⊙) in the Milky Way. Their detection is mainly hindered by high extinction.

4 Stepheson 2, with M ≈ 5x10 M⊙, is part of a huge structure. 5 Westerlund 1, containing 10 M ⊙, formed monolythically, in a single burst. h & χ Per, the core of Per OB1 (Roth Ritter; APOD 0901093)

50’ = 30 pc @ 2.1 kpc D4

> 25 RSGs (Davies et al. 2007, ApJ 671, 781; Negueruela et al. 2012, A&A 547, D2 A14)

4 Implied mass ≈ 5x10 M⊙ AV ≈ 11 Behind dust layer (LDN 515) Age 18-20 Myr D49 @ d = 6kpc D1 Stephenson 1990 (AJ 99, 1867) Nakaya et al. 2001 (AJ 122, 876) Ortolani et al. 2002 (A&A 391, 179) GLIMPSE 3-colour image Stephenson 2

> 25 RSGs (Davies et al. 2007, ApJ 671, 781; Negueruela et al. 2012, A&A 547, A14)

Clark et al. 2014, A&A 561, A15

Westerlund 1 is completely isolated!

Westerlund 1 is completely isolated!