XMM-Newton study of the very young stellar cluster IC 348

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: preib@mpifr-bonn.mpg.de
² Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: hzinnecker@aip.de

Received: 6 February 2004
Accepted: 8 April 2004

Abstract

We analyze a XMM-Newton X-ray imaging observation of the very young stellar cluster IC 348 with an observing time of 12 h and a corresponding total (all detector) MOS-equivalent exposure time of 207 ks. Our observation is strongly affected by a very intense solar particle flare, due to which only the first half of the exposure time can be used for scientific analysis. We compare the X-ray sources seen by XMM-Newton with those found in our previous Chandra study of IC 348 and find that XMM-Newton reveals 71 new X-ray sources, most of which are located outside the field-of-view of the Chandra observation. 20 of these new X-ray sources can be identified with known cluster members, and 19 sources are likely to be new low-mass members of the cluster. The lightcurves of the XMM-Newton sources show at most moderate levels of variability, but no large flares. We compare the spectral fitting results for 10 stars for which we have good spectra from both Chandra and XMM-Newton, and find good agreement in the fitted plasma temperatures, but a systematic difference in the fitted values of the hydrogen column density (extinction). We finally discuss the X-ray properties of the optically bright B1 star o Per and the X-ray detections among the deeply embedded young stellar objects to the south of the optical cluster center (including HH 211-mm), and find that none of the 23 spectroscopically identified brown dwarfs in IC 348 is detected in our XMM-Newton data.