M. Tsujimoto et al. 2005 ApJS 160 503 doi:10.1086/432093
Iron Fluorescent Line Emission from Young Stellar Objects in the Orion Nebula
FREEM. Tsujimoto1, E. D. Feigelson1, N. Grosso2, G. Micela3, Y. Tsuboi4, F. Favata5, H. Shang6 and J. H. Kastner7
Show affiliationsWe present the result of a systematic search for the iron Kα fluorescent line at ~6.4 keV among 1616 X-ray sources detected by ultradeep Chandra observations of the Orion Nebula Cluster and the obscured Orion Molecular Cloud 1 population as part of the Chandra Orion Ultradeep Project (COUP). Seven sources are identified to have an excess emission at ~6.4 keV among 127 control sample sources with significant counts in the 6.0-9.0 keV band. These seven sources are young stellar objects (YSOs) characterized by intense flarelike flux variations, thermal spectra, and near-infrared (NIR) counterparts. The observed equivalent widths of the line cannot be attributed to the florescence by interstellar or circumstellar matter along the line of sight. The X-ray spectral fits and NIR colors of the 6.4 keV sources show that these sources have X-ray absorption of 
1 × 1022 cm-2 and NIR excess emission, which is not expected when the fluorescence occurs at the stellar photosphere. We therefore conclude that the iron fluorescent line of YSOs arises from reflection off of circumstellar disks, which are irradiated by the hard X-ray continuum emission of magnetic reconnection flares.
- Subject headings
ISM: individual (OMC-1); open clusters and associations: individual (Orion Nebula Cluster); scattering; stars: pre-main sequence; X-rays: stars
- Dates
-
Issue 2 (2005 October)
Received 2004 September 20, accepted for publication 2004 December 10
-
Iron Fluorescent Line Emission from Young Stellar Objects in the Orion Nebula
M. Tsujimoto et al. 2005 ApJS 160 503
-
Magnetic switching of Fe-porphyrin molecules adsorbed on surfaces: An XAFS and XMCD study
Klaus Baberschke 2009 J. Phys.: Conf. Ser. 190 012012
-
The Supercritical Pile Model for Gamma-Ray Bursts: Spectro-Temporal Properties
A. Mastichiadis and D. Kazanas 2006 ApJ 645 416
-
Dust-to-Gas Ratio and Metallicity in Dwarf Galaxies
Hiroyuki Hirashita 1999 ApJ 522 220
-
Electric current during electrophoretic deposition of conjugated polymer
Kazuya Tada and Mitsuyoshi Onoda 2009 J. Phys. D: Appl. Phys. 42 132001
-
A cold atmospheric pressure plasma jet controlled with spatially separated dual-frequency excitations
Z Cao et al 2009 J. Phys. D: Appl. Phys. 42 222003
-
A time variation of proton-electron mass ratio and grand unification
X. Calmet and H. Fritzsch 2006 Europhys. Lett. 76 1064
-
Symmetries of string, M- and F-theories
Eric Bergshoeff and Antoine Van Proeyen 2001 Class. Quantum Grav. 18 3083
-
Drift Effects and the Cosmic Ray Density Gradient in a Solar Rotation Period: First Observation with the Global Muon Detector Network (GMDN)
Y. Okazaki et al. 2008 ApJ 681 693
-
Exact relativistic static charged dust discs and non-axisymmetric structures
D Vogt and P S Letelier 2004 Class. Quantum Grav. 21 3369