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ROSAT HRI, Chandra and optical images of the very young stellar cluster IC 348 detecting X-ray emission from 4 of 13 known brown dwarfs.
( credit: T. Preibisch, MPIfR, H. Zinnecker AIP)
While 115 of these sources can be identified with known cluster members, 58 X-ray sources are most likely new, still unidentified cluster members. About 80% of all known cluster members with masses between ~ 0.15 M_sun and 2 M_sun are visible as X-ray sources in our image.
We discover X-ray emission at levels of ~ 10^28 erg/sec from 4 of 13 known brown dwarfs and from 3 of 12 brown dwarf candidates in IC 348. We also detect X-ray emission from two deeply embedded objects, presumably class I protostars, south of the cluster center.
The upper picture shows the full CHANDRA image, about 17' times 17'. In our detailed analysis of the CHANDRA data we could detect 215 individual X-ray sources.
The next two images show the central region of IC348 as seen by the ROSAT ROSAT HRI and by CHANDRA. Note the superb spatial resolution of the CHANDRA data, resulting in a much sharper image.
The lower two frames show optical and X-ray images of the central region of IC348. The optical true color (V,R,I) image is obtained with the 1.2 m Telescope on Calar Alto Observatory. The true color X-ray image of the same area is shown as seen by Chandra.
For detailed information see our paper (Preibisch & Zinnecker, Astronomical Journal, in press).
( credit: T. Preibisch, MPIfR, H. Zinnecker AIP)