The starburst cluster westerlund 1: The initial mass function and mass segregation
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Lim, Beomdu; Chun, Moo-Young; Sung, Hwankyung; Park, Byeong-Gon; Lee, Jae-Joon; Sohn, Sangmo T; Hur, Hyeonoh; Bessell, Michael
Description
Westerlund 1 is the most important starburst cluster in the Galaxy due to its massive star content. We have performed BVIC and JKS photometry to investigate the initial mass function (IMF). By comparing the observed color with the spectral-type-intrinsic-color relation, we obtain the mean interstellar reddening of 〈E(B-V)〉 = 4.19 ± 0.23 and 〈E(J-KS )〉 = 1.70 ± 0.21. Due to the heavy extinction toward the cluster, the zero-age main sequence fitting method based on optical photometry proved to be...[Show more]
dc.contributor.author | Lim, Beomdu | |
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dc.contributor.author | Chun, Moo-Young | |
dc.contributor.author | Sung, Hwankyung | |
dc.contributor.author | Park, Byeong-Gon | |
dc.contributor.author | Lee, Jae-Joon | |
dc.contributor.author | Sohn, Sangmo T | |
dc.contributor.author | Hur, Hyeonoh | |
dc.contributor.author | Bessell, Michael | |
dc.date.accessioned | 2015-12-13T22:15:53Z | |
dc.identifier.issn | 0004-6256 | |
dc.identifier.uri | http://hdl.handle.net/1885/70605 | |
dc.description.abstract | Westerlund 1 is the most important starburst cluster in the Galaxy due to its massive star content. We have performed BVIC and JKS photometry to investigate the initial mass function (IMF). By comparing the observed color with the spectral-type-intrinsic-color relation, we obtain the mean interstellar reddening of 〈E(B-V)〉 = 4.19 ± 0.23 and 〈E(J-KS )〉 = 1.70 ± 0.21. Due to the heavy extinction toward the cluster, the zero-age main sequence fitting method based on optical photometry proved to be inappropriate for the distance determination, while the near-infrared photometry gave a reliable distance to the cluster - 3.8 kpc from the empirical relation. Using the recent theoretical stellar evolution models with rotation, the age of the cluster is estimated to be 5.0 ± 1.0 Myr. We derived the IMF in the massive part and obtained a fairly shallow slope of Γ = -0.8 ± 0.1. The integration of the IMF gave a total mass for the cluster in excess of 5.0 × 104 M⊙. The IMF shows a clear radial variation indicating the presence of mass segregation. We also discuss the possible star formation history of Westerlund 1 from the presence of red supergiants and relatively low luminosity yellow hypergiants. | |
dc.publisher | University of Chicago Press | |
dc.rights | Author/s retain copyright | |
dc.source | Astronomical Journal | |
dc.subject | Keywords: open clusters and associations: individual (Westerlund 1); stars: luminosity function, mass function | |
dc.title | The starburst cluster westerlund 1: The initial mass function and mass segregation | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.identifier.citationvolume | 145 | |
dc.date.issued | 2013 | |
local.identifier.absfor | 020100 - ASTRONOMICAL AND SPACE SCIENCES | |
local.identifier.ariespublication | f5625xPUB2359 | |
local.type.status | Published Version | |
local.contributor.affiliation | Lim, Beomdu, Sejong University | |
local.contributor.affiliation | Chun, Moo-Young, Korea Astronomy and Space Science Institute | |
local.contributor.affiliation | Sung, Hwankyung, Sejong University | |
local.contributor.affiliation | Park, Byeong-Gon, Korea Astronomy and Space Science Institute | |
local.contributor.affiliation | Lee, Jae-Joon, Korea Astronomy and Space Science Institute | |
local.contributor.affiliation | Sohn, Sangmo T, Space Telescope Science Institute | |
local.contributor.affiliation | Hur, Hyeonoh, Sejong University | |
local.contributor.affiliation | Bessell, Michael, College of Physical and Mathematical Sciences, ANU | |
local.bibliographicCitation.issue | 2 | |
local.bibliographicCitation.startpage | 19 | |
local.identifier.doi | 10.1088/0004-6256/145/2/46 | |
dc.date.updated | 2016-02-24T08:57:01Z | |
local.identifier.scopusID | 2-s2.0-84872711703 | |
local.identifier.thomsonID | 000313571600020 | |
dcterms.accessRights | Open Access | |
Collections | ANU Research Publications |
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