Detection of nonthermal X-ray structures near the galactic center with Chandra

Atsushi Senda, Katsuji Koyama, Ken Ebisawa, Jun Kataoka, Yoshiaki Sofue, Bosch-Ramon, Pietsch

Research output: Contribution to journalArticle

Abstract

We have discovered a number of nonthermal X-ray features within central 40 pc region of the Galactic center by analysing 600-ksec observations of Chandra archival data. Most of the detected X-ray structures exhibit small-scale knot-like morphologies and their spectra are well reproduced by single hard power-law with photon indices of 1-2. Among them, the most outstanding features are the three X-ray knots which are aligned on a straight line from the potition of Sgr A* to north-northwest direction. The X-ray properties of these knots lead us to suspect that they are X-ray jets ejected from Sgr A* in the recent past. In addition, we have obtained an indication that the summed flux of nonthermal diffuse X-rays within 30 pc of the GC seems to be smoothly connected to the 20-100 keV flux detected with INTEGRAL IBIS/ISGRI. These results suggest that the origin of GC hard X-rays (or High energy Gamma-rays) is not (or partly) from the Galactic nucleus.

Original languageEnglish
Pages (from-to)24-28
Number of pages5
JournalProceedings of the International Astronomical Union
Volume1
DOIs
Publication statusPublished - 2005
Externally publishedYes

Fingerprint

x rays
galactic nuclei
detection
power law
indication
gamma rays
photons
energy
index

Keywords

  • Galaxy: center
  • ISM: jets and outflows
  • X-rays: ISM

ASJC Scopus subject areas

  • Astronomy and Astrophysics

Cite this

Detection of nonthermal X-ray structures near the galactic center with Chandra. / Senda, Atsushi; Koyama, Katsuji; Ebisawa, Ken; Kataoka, Jun; Sofue, Yoshiaki; Bosch-Ramon; Pietsch.

In: Proceedings of the International Astronomical Union, Vol. 1, 2005, p. 24-28.

Research output: Contribution to journalArticle

Senda, Atsushi ; Koyama, Katsuji ; Ebisawa, Ken ; Kataoka, Jun ; Sofue, Yoshiaki ; Bosch-Ramon ; Pietsch. / Detection of nonthermal X-ray structures near the galactic center with Chandra. In: Proceedings of the International Astronomical Union. 2005 ; Vol. 1. pp. 24-28.
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AU - Koyama, Katsuji

AU - Ebisawa, Ken

AU - Kataoka, Jun

AU - Sofue, Yoshiaki

AU - Bosch-Ramon,

AU - Pietsch,

PY - 2005

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AB - We have discovered a number of nonthermal X-ray features within central 40 pc region of the Galactic center by analysing 600-ksec observations of Chandra archival data. Most of the detected X-ray structures exhibit small-scale knot-like morphologies and their spectra are well reproduced by single hard power-law with photon indices of 1-2. Among them, the most outstanding features are the three X-ray knots which are aligned on a straight line from the potition of Sgr A* to north-northwest direction. The X-ray properties of these knots lead us to suspect that they are X-ray jets ejected from Sgr A* in the recent past. In addition, we have obtained an indication that the summed flux of nonthermal diffuse X-rays within 30 pc of the GC seems to be smoothly connected to the 20-100 keV flux detected with INTEGRAL IBIS/ISGRI. These results suggest that the origin of GC hard X-rays (or High energy Gamma-rays) is not (or partly) from the Galactic nucleus.

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