A Chandra observation of the obscured star-forming complex W40

Michael A. Kuhn, Konstantin V. Getman, Eric D. Feigelson, Bo Reipurth, Steven A. Rodney, Gordon P. Garmire

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

The young stellar cluster illuminating the W40 Hii region, one of the nearest massive star-forming regions, has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. We detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1M under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in Ks-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5M. However, other cluster properties, including a ≲1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported.

Original languageEnglish (US)
Pages (from-to)2485-2506
Number of pages22
JournalAstrophysical Journal
Volume725
Issue number2
DOIs
StatePublished - Dec 20 2010

Fingerprint

occultation
stars
dust
x rays
star formation
star clusters
massive stars
illuminating
flares
observatories
spatial variation
observatory
luminosity
rings
detectors
estimates
profiles
excitation
young

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kuhn, Michael A. ; Getman, Konstantin V. ; Feigelson, Eric D. ; Reipurth, Bo ; Rodney, Steven A. ; Garmire, Gordon P. / A Chandra observation of the obscured star-forming complex W40. In: Astrophysical Journal. 2010 ; Vol. 725, No. 2. pp. 2485-2506.
@article{7e686631c02f4c84a6d3e4dde1d27656,
title = "A Chandra observation of the obscured star-forming complex W40",
abstract = "The young stellar cluster illuminating the W40 Hii region, one of the nearest massive star-forming regions, has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. We detect 225 X-ray sources, of which 85{\%} are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1M⊙ under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in Ks-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5M⊙. However, other cluster properties, including a ≲1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported.",
author = "Kuhn, {Michael A.} and Getman, {Konstantin V.} and Feigelson, {Eric D.} and Bo Reipurth and Rodney, {Steven A.} and Garmire, {Gordon P.}",
year = "2010",
month = "12",
day = "20",
doi = "10.1088/0004-637X/725/2/2485",
language = "English (US)",
volume = "725",
pages = "2485--2506",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

A Chandra observation of the obscured star-forming complex W40. / Kuhn, Michael A.; Getman, Konstantin V.; Feigelson, Eric D.; Reipurth, Bo; Rodney, Steven A.; Garmire, Gordon P.

In: Astrophysical Journal, Vol. 725, No. 2, 20.12.2010, p. 2485-2506.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A Chandra observation of the obscured star-forming complex W40

AU - Kuhn, Michael A.

AU - Getman, Konstantin V.

AU - Feigelson, Eric D.

AU - Reipurth, Bo

AU - Rodney, Steven A.

AU - Garmire, Gordon P.

PY - 2010/12/20

Y1 - 2010/12/20

N2 - The young stellar cluster illuminating the W40 Hii region, one of the nearest massive star-forming regions, has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. We detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1M⊙ under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in Ks-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5M⊙. However, other cluster properties, including a ≲1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported.

AB - The young stellar cluster illuminating the W40 Hii region, one of the nearest massive star-forming regions, has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. We detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1M⊙ under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in Ks-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5M⊙. However, other cluster properties, including a ≲1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported.

UR - http://www.scopus.com/inward/record.url?scp=78650130034&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78650130034&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/725/2/2485

DO - 10.1088/0004-637X/725/2/2485

M3 - Article

AN - SCOPUS:78650130034

VL - 725

SP - 2485

EP - 2506

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

ER -