TY  - JOUR
A1  - Oskinova, Lida
A1  - Sun, W.
A1  - Evans, C. J.
A1  - Henault-Brunet, V.
A1  - Chu, Y.-H.
A1  - Gallagher, J. S.
A1  - Guerrero, Martín A.
A1  - Gruendl, R. A.
A1  - Güdel, M.
A1  - Silich, S.
A1  - Chen, Y.
A1  - Naze, Y.
A1  - Hainich, Rainer
A1  - Reyes-Iturbide, J.
T1  - Discovery of x-ray emission from young suns in the small magellanic  cloud
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low-and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low-and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.
KW  - Magellanic Clouds
KW  - ISM: bubbles
KW  - H II regions
KW  - stars: winds, outflows
KW  - stars: pre-main sequence
KW  - X-rays: stars
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/765/1/73
SN  - 0004-637X
VL  - 765
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Ignace, Rico
A1  - Gayley, Kenneth G.
A1  - Hamann, Wolf-Rainer
A1  - Huenemoerder, David P.
A1  - Oskinova, Lida
A1  - Pollock, Andy M. T.
A1  - McFall, Michael
T1  - THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds.
KW  - stars: individual (WR 6)
KW  - stars: winds, outflows
KW  - stars: Wolf-Rayet
KW  - X-rays: stars
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/775/1/29
SN  - 0004-637X
VL  - 775
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -