Miquela Vigil | Searcharxiv

arXiv2008

The Embedded Massive Star Forming Region RCW 38

RCW~38 is a uniquely young ($<$1 Myr), embedded ($A_V \sim 10$) stellar cluster surrounding a pair of early O stars ($\sim$O5.5) and is one of the few regions within 2 kpc other than Orion to contain over 1000 members. X-ray and deep near-infrared observations reveal a dense cluster with over 200 X-ray sources and 400 infrared sources embedded in a diffuse hot plasma within a 1 pc diameter. The central O star has evacuated its immediate surroundings of dust, creating a wind bubble $\sim$0.1 pc in radius that is confined by the surrounding molecular cloud, as traced by millimeter continuum and molecular line emission. The interface between the bubble and cloud is a region of warm dust and ionized gas, which shows evidence for ongoing star formation. Extended warm dust is found throughout a 2--3 pc region and coincides with extended X-ray plasma. This is evidence that the influence of the massive stars reaches beyond the confines of the O star bubble. RCW~38 appears similar in structure to RCW~49 and M~20 but is at an earlier evolutionary phase. RCW~38 appears to be a blister compact H{\small II} region lying just inside the edge of a giant molecular cloud.

astro-ph↗

arXiv2007

X-ray and IR Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 108

We report on the results of an approximately 90 ks Chandra observation of a complex region that hosts multiple sites of recent and active star formation in ARA OB1a. The field is centered on the embedded cluster RCW 108-IR and includes and a large portion of the open cluster NGC 6193. We detect over 420 X-ray sources in the field and combined these data with deep near-IR, Spitzer/IRAC and MSX mid-IR data. We find about 360 of the X-ray sources have near--IR counterparts. We divide the region into 5 parts based on the X-ray point source characteristics and extended 8 micron emission. The most clearly defined regions are the central region - identified by embedded sources with high luminosities in the both the near-IR and X-ray as well as high X-ray temperatures (about 3 keV) and the eastern region - identified by low extinction and 1 keV X-ray temperatures. Other regions, identified by their directional relationship to RCW 108-IR are less uniform - representing combinations of the first two regions, independent star formation epochs, or both. Over 18% percent of the cluster members with over 100 counts exhibit flares. Overall about 50% of the stars appear to have optically thick disks when IRAC data are employed. The largest fraction of X-ray sources are best described as possessing some disk material via a more detailed extinction fitting. We estimate that the total number of pre--main sequence stars in the field is about 1600. Approximately 800 are confined to (1.1 pc) central region.

astro-ph↗