A<i>Chandra</i>ACIS Study of 30 Doradus. II. X-Ray Point Sources in the Massive Star Cluster R136 and Beyond

Townsley, Leisa K.; Broos, P. S.; Feigelson, E. D.; Garmire, G. P.; Getman, Konstantin V.

doi:10.1086/500535

Cited by 97 publications

(129 citation statements)

References 57 publications

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“…The primary data products from the Chandra X-ray Centre's automated processing were downloaded and examined, but no obvious source was found coincident with VFTS698. This supports the analysis of the 1999 data by Townsley et al (2006) who did not report a detection at the position of VFTS698 (given a lower detection limit of 5 counts in 21 870 s, which equates to a limiting full-band luminosity of ∼1 × 10 33 erg s −1 , with the brightest source detected being <10 36 erg s −1 ).…”

Section: X-ray Datasupporting

confidence: 84%

The VLT-FLAMES Tarantula Survey

Ramírez-Agudelo

Sana

Koter

et al. 2017

A&A

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Aims. We present an analysis of a peculiar supergiant B-type star (VFTS698/Melnick 2/Parker 1797) in the 30 Doradus region of the Large Magellanic Cloud which exhibits characteristics similar to the broad class of B[e] stars. Methods. We analyse optical spectra from the VLT-FLAMES survey, together with archival optical and infrared photometry and X-ray imaging to characterise the system. Results. We find radial velocity variations of around 400 km s −1 in the high excitation Si iv, N iii and He ii spectra, and photometric variability of ∼0.6 mag with a period of 12.7 d. In addition, we detect long-term photometric variations of ∼0.25 mag, which may be due to a longer-term variability with a period of ∼400 d. Conclusions. We conclude that VFTS698 is likely an interacting binary comprising an early B-type star secondary orbiting a veiled, more massive companion. Spectral evidence suggests a mid-to-late B-type primary, but this may originate from an optically-thick accretion disc directly surrounding the primary.

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Section: X-ray Datasupporting

confidence: 84%

The VLT-FLAMES Tarantula Survey

Ramírez-Agudelo

Sana

Koter

et al. 2017

A&A

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“…The best-fit values of plasma temperature (k B T ), the volume emission measure (EM ), and the extinction column density (N H ) were derived. The photometric and spectroscopic tables (Tables 1 and 2) are in a format similar to those found in associated papers Townsley et al 2006;Wang et al 2007; J. Wang et al 2007, in preparation;Broos et al 2007).…”

Section: Photometry and Time Variabilitymentioning

confidence: 97%

“…The software failed to detect sources in crowded regions, where we manually added candidate sources with the aid of smoothed images in different kernel sizes and PSF-deconvolved images obtained using a maximum likelihood technique (Lucy 1974;Townsley et al 2006). In total, 556 X-ray source candidates were identified, including 60 manually added sources.…”

Section: Observationsmentioning

confidence: 99%

An X‐Ray Imaging Study of the Stellar Population in RCW 49

Tsujimoto

Feigelson

Townsley

et al. 2007

ApJ

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We present the results of a high-resolution X-ray imaging study of the stellar population in the Galactic massive star-forming region RCW 49 and its central OB association Westerlund 2. We obtained a $40 ks X-ray image of a $17 0 ; 17 0 field using the Chandra X-Ray Observatory and deep NIR images using the Infrared Survey Facility in a concentric $8:3 0 ; 8:3 0 region. We detected 468 X-ray sources and identified optical, NIR, and Spitzer MIR counterparts for 379 of them. The unprecedented spatial resolution and sensitivity of the X-ray image, enhanced by optical and infrared imaging data, yielded the following results: (1) The central OB association Westerlund 2 is resolved for the first time in the X-ray band. X-ray emission is detected from all spectroscopically identified early-type stars in this region.(2) Most ($86%) X-ray sources with optical or infrared identifications are cluster members in comparison with a control field in the Galactic plane. (3) A loose constraint (2-5 kpc) for the distance to RCW 49 is derived from the mean X-ray luminosity of T Tauri stars. (4) The cluster X-ray population consists of low-mass pre-main-sequence and earlytype stars as obtained from X-ray and NIR photometry. About 30 new OB star candidates are identified. (5) We estimate a cluster radius of 6 0 -7 0 based on the X-ray surface number density profiles. (6) A large fraction ($90%) of cluster members are identified individually using complimentary X-ray and MIR excess emission. (7) The brightest five X-ray sources, two Wolf-Rayet stars and three O stars, have hard thermal spectra.

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“…To find star-forming regions building up hundreds of O stars one has to look towards giant extragalactic Hii regions, the nearest of which is 30 Doradus in the Large Magellanic Cloud, a satellite galaxy of our Milky Way at a distance at 55 kpc. The giant star-forming region 30 Doradus is thought to contain up to a hundred thousand young stars, including more than 400 O stars (Hunter et al, 1995;Walborn & Blades, 1997;Townsley et al, 2006). Figure 19 shows that the star formation process spans many orders of magnitude in spatial scale and mass, ranging from stellar groups with no or only a few high-mass stars to massive clusters with several tens of thousands of stars and dozens if not hundreds of O stars.…”

Section: Spatial Distributionmentioning

confidence: 99%

Physical Processes in the Interstellar Medium

Klessen

Glover

2015

Saas-Fee Advanced Course

170

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Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understanding its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly turbulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where the different components are intricately linked together by complex feedback loops. Describing the interstellar medium is truly a multi-scale and multi-physics problem. In these lecture notes we introduce the microphysics necessary to better understand the interstellar medium. We review the relations between large-scale and small-scale dynamics, we consider turbulence as one of the key drivers of galactic evolution, and we review the physical processes that lead to the formation of dense molecular clouds and that govern stellar birth in their interior.

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AChandraACIS Study of 30 Doradus. II. X-Ray Point Sources in the Massive Star Cluster R136 and Beyond

Cited by 97 publications

References 57 publications

The VLT-FLAMES Tarantula Survey

The VLT-FLAMES Tarantula Survey

An X‐Ray Imaging Study of the Stellar Population in RCW 49

Physical Processes in the Interstellar Medium

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