2008A&A...478..137B


Query : 2008A&A...478..137B

2008A&A...478..137B - Astronomy and Astrophysics, volume 478, 137-149 (2008/1-4)

Intermediate to low-mass stellar content of Westerlund 1.

BRANDNER W., CLARK J.S., STOLTE A., WATERS R., NEGUERUELA I. and GOODWIN S.P.

Abstract (from CDS):

We have analysed near-infrared NTT/SofI observations of the starburst cluster Westerlund 1, which is among the most massive young clusters in the Milky Way. A comparison of colour-magnitude diagrams with theoretical main-sequence and pre-main sequence evolutionary tracks yields improved extinction and distance estimates of AKs=1.13±0.03mag and d=3.55±0.17kpc (DM=12.75±0.10mag). The pre-main sequence population is best fit by a Palla & Stahler (1999ApJ...525..772P) isochrone for an age of 3.2Myr, while the main sequence population is in agreement with a cluster age of 3 to 5Myr. An analysis of the structural parameters of the cluster yields that the half-mass radius of the cluster population increases towards lower mass, indicative of the presence of mass segregation. The cluster is clearly elongated with an eccentricity of 0.20 for stars with masses between 10 and 32M, and 0.15 for stars with masses in the range 3 to 10M. We derive the slope of the stellar mass function for stars with masses between 3.4 and 27M. In an annulus with radii between 0.75 and 1.5pc from the cluster centre, we obtain a slope of Γ=-1.3. Closer in, the mass function of Westerlund 1 is shallower with Γ=-0.6. The extrapolation of the mass function for stars with masses from 0.08 to 120M yields an initial total stellar mass of ≃52000M, and a present-day mass of 20000 to 45000M (about 10 times the stellar mass of the Orion nebula cluster, and 2 to 4 times the mass of the NGC 3603 young cluster), indicating that Westerlund1 is the most massive starburst cluster identified to date in the Milky Way.

Abstract Copyright:

Journal keyword(s): stars: evolution - stars: formation - stars: luminosity function, mass function - stars: pre-main sequence - stars: supernovae: general - Galaxy: open clusters and associations: individual: Westerlund 1

Simbad objects: 24

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Number of rows : 24
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12107 1
2 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 16525 1
3 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2209 1
4 NGC 2070 Cl* 05 38 42 -69 06.0     7.25     ~ 359 1
5 RMC 136 Cl* 05 38 42.396 -69 06 03.36           ~ 1908 1
6 * zet Pup BY* 08 03 35.04754 -40 00 11.3321 0.89 1.98 2.25 2.36 2.58 O4I(n)fp 1139 1
7 NAME Car Arm PoG 10 00 -60.0           ~ 421 1
8 Cl Westerlund 2 OpC 10 23 58.1 -57 45 49           ~ 329 0
9 HD 97950 Cl* 11 15 07.346 -61 15 38.52 9.64 9.83 9.03 9.69   ~ 187 2
10 NGC 3603 OpC 11 15 11 -61 15.5           ~ 1032 1
11 NGC 4038 GiP 12 01 53.002 -18 52 03.32   10.91   9.74 11.0 ~ 1313 1
12 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1646 0
13 NGC 4039 GiP 12 01 53.8 -18 53 06   11.08   9.77   ~ 1151 1
14 NAME Crux Arm PoG 12 30 -60.0           ~ 88 0
15 Cl Westerlund 1 Cl* 16 47 04.00 -45 51 04.9           ~ 527 0
16 Cl* Westerlund 1 W 60 s*b 16 47 04.1335644720 -45 51 52.259535324   22.8 18.50 16.041 13.384 B0Iab 17 0
17 Cl* Westerlund 1 W 29 s*b 16 47 04.4118843432 -45 50 39.933732768   22.6 18.66 16.02 13.38 O9.5/B0.5Ia 10 0
18 Cl* Westerlund 1 W 15 * 16 47 06.6306037464 -45 50 29.723762580   22.8 18.96 16.38 13.75 O9Ib 24 0
19 Cl* Westerlund 1 CN O WR* 16 47 07.6630825488 -45 52 35.964833052       16.886 14.047 WN6o 13 0
20 WR 77s WR* 16 47 08.3538521592 -45 50 45.414739212     19.69 16.59 13.68 WN7b 27 0
21 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13453 0
22 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 700 0
23 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 503 0
24 Cl Ruprecht 136 OpC 17 59 18 -24 42.6           ~ 16 0

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2023.02.06-07:35:21

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