X-Ray Reflection Nebulae with Large Equivalent Widths of Neutral Iron Ka Line in the Sgr C Region

Abstract

This paper reports on the first results of the Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Ka from neutral or low-ionized Fe. One of them, M359.38-0.00, is newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M359.43-0.07 and M359.47-0.15, after subtracting the Galactic center diffuse X-ray emission (GCDX), exhibit strong Ka line from FeI with large equivalent widths (EWs) of 2.0-2.2keV and clear Kb of FeI. The GCDX in the Sgr C region is composed of the 6.4keV- and 6.7keV-associated components. These are phenomenologically decomposed by taking relations between EWs of the 6.4keV and 6.7keV lines. Then the former EWs against the associated continuum in the bright clump regions are estimated to be 2.4(+2.3_-0.7)keV. Since the two different approaches give similar large EWs of 2keV, we strongly suggest that the 6.4keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae).

Accepted for publication in PASJ

References in corpus (8)

• Reproducibility of Non-X-ray Background for the X-ray Imaging Spectrometer aboard Suzaku
• Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission
• The Origin of Diffuse X-ray and $\gamma$-ray Emission from the Galactic Center Region: Cosmic Ray Particles
• A Chandra Catalog of X-ray Sources in the Central 150 pc of the Galaxy
• Discovery of Variable Iron Fluorescence from Reflection Nebulae in the Galactic Center
• Restoring the Suzaku Source Position Accuracy and Point-Spread Function
• A Time-Variable X-Ray Echo: Indications of a Past Flare of the Galactic-Center Black Hole
• Suzaku Spectroscopy of an X-Ray Reflection Nebula and a New Supernova Remnant Candidate in the Sgr B1 Region

Cited by in corpus (18)

• Discovery of a superluminal Fe K echo at the Galactic Center: The glorious past of Sgr A* preserved by molecular clouds
• Fading hard X-ray emission from the Galactic Centre molecular cloud Sgr B2
• Traces of past activity in the Galactic Centre
• Galactic Center Research: Manifestations of the Central Black Hole
• X-ray Echo from the Sagittarius C Complex and 500-year Activity History of Sagittarius A*
• The X-ray lightcurve of Sgr A* over the past 150 years inferred from Fe-Ka line reverberation in Galactic Centre molecular clouds
• Discovery of K-Shell Emission Lines of Neutral Atoms in the Galactic Center Region
• An X-Ray Face-on View of the Sgr B Molecular Clouds Observed with Suzaku
• Diffuse X-Ray Sky in the Galactic Center
• Glimpses of the past activity of Sgr A* inferred from X-ray echoes in Sgr C
• An X-ray survey of the central molecular zone: variability of the Fe Ka emission line
• Origin of the Galactic Diffuse X-ray Emission: Iron K-shell Line Diagnostics
• Fe Ka line emission from the Arches cluster region - evidence for ongoing particle bombardment?
• Exploring the dark accelerator HESS J1745-303 with Fermi Large Area Telescope
• The kpc Scale Fe K$\alpha$ Emission in the Compton Thin Seyfert 2 Galaxy NGC 4388 resolved by Chandra
• Suzaku Observation Adjacent to the South End of the Radio Arc
• SRG/eROSITA view of X-ray reflection in the Central Molecular Zone: a snapshot in September-October 2019
• Suzaku Observations of the Great Annihilator and the Surrounding Diffuse Emissions