A FIRST LOOK AT THE X-RAY POPULATION OF THE YOUNG MASSIVE CLUSTER VVV CL077

作者：Bodaghee Arash^*; Tomsick John A; Fornasini Francesca; Rahoui Farid; Bauer Franz E

来源：Astrophysical Journal, 2015, 801(1): 49.

DOI：10.1088/0004-637X/801/1/49

• infrared: stars
• open clusters and associations: individual (VVV CL077)
• stars: early-type
• X-rays: stars

Multi-wavelength analysis of the young massive cluster VVV CL077 is presented for the first time. Our Chandra survey of this region enabled the detection of three X-ray emitting stellar members of the cluster, as well as a possible diffuse X-ray component that extends a few arcseconds from the cluster core with an intrinsic flux of (9 +/- 3) x 10(-14) erg cm(-2) s(-1) in the 0.5-10 keV band. Infrared spectra we obtained for two of these X-ray point sources show absorption lines typical of the atmospheres of massive O stars. The X-ray spectrum from the visible extent of VVV CL077 i.e., a 15 '' radius around the cluster, can be modeled with an absorbed power law with N-H = (6(-3)(+4)) x 10(22) cm(-2) and Gamma = 2 +/- 1. In addition, the X-ray core of VVV CL077 coincides with diffuse emission seen in the infrared band and with a local maximum in the radio continuum map. A possible association with a neighboring H Pi region would place VVV CL077 at a distance of around 11 kpc, on the far side of the Norma Arm. At this distance, the cluster is 0.8 pc wide with a mass density of (1-4) x 10(3) M-circle dot pc(-3).

• 出版日期2015-3-1