Discovery of X-Ray Emission from Young Suns in the Small Magellanic Cloud

Autor(en)

Lidia M. Oskinova, W. Sun, C. J. Evans, V. Hénault-Brunet, Y.-H. Chu, J. S., III Gallagher, Mariela A. Guerrero, Robert A. Gruendl, M. Güdel, S. Silich, Yang Chen, Yaël Nazé, Rainer Hainich, J. Reyes-Iturbide

Abstrakt

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.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Instituto de Astrofísica de Andalucía, The Royal Observatory, Edinburgh, Universität Potsdam, Nanjing University, University of Edinburgh, University of Illinois at Urbana-Champaign, University of Wisconsin, Madison, National Institute of Astrophysics, Optics and Electronics (INAOE), Université de Liège, Universidade Estadual de Santa Cruz

Journal

The Astrophysical Journal: an international review of astronomy and astronomical physics

Band

765

Anzahl der Seiten

12

ISSN

0004-637X

DOI

https://doi.org/10.1088/0004-637X/765/1/73

Publikationsdatum

03-2013

Peer-reviewed

Ja

ÖFOS 2012

103004 Astrophysik, 103003 Astronomie

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/6b4424e7-a356-45d1-bced-cdf80f622c23