A Chandra Study of Sagittarius A East: A Supernova Remnant Regulating the Activity of Our Galactic Center?
By Y. Maeda, F. Baganoff, Eric D. Feigelson, Mark R. Morris, M. Bautz, W. N. Brandt, D. Burrows, J. Doty, G. Garmire, S. Pravdo and 2 more. 2001
163 citations recorded by the source corpus.
We report on the X-ray emission from the shell-like, nonthermal radio source Sgr A East (SNR 000.0+00.0), located in the inner few parsecs of the Galaxy based on observations made with the ACIS detector on board the Chandra X-Ray Observatory. This is the first time Sgr A East has been clearly resolved from other complex structures in the region. The X-ray-emitting region is concentrated within the central ≃2 pc of the larger radio shell. The spectrum shows strong Kα lines from highly ionized ions of S, Ar, Ca, and Fe. A simple isothermal plasma model gives electron temperature ~2 keV, absorption column ~1 × 1023 H cm-2, luminosity ~8 × 1034 ergs s-1 in the 2-10 keV band, and gas mass ~2η1/2 M☉ with a filling factor η. The plasma appears to be rich in heavy elements, overabundant by roughly a factor of 4 with respect to solar abundances, and shows a spatial gradient of elemental abundance; the spatial distribution of iron is more compact than that of the lighter elements. The gas mass and elemental abundance of the X-ray emission support the long-standing hypothesis that Sgr A East is a supernova remnant (SNR), perhaps produced by the Type II supernova explosion of a massive star with a main-sequence mass of 13-20 M☉. The combination of the radio and X-ray morphologies classifies Sgr A East as a new metal-rich "mixed morphology" (MM) SNR. The size of the Sgr A East radio shell is the smallest of the known MM SNRs, which strongly suggests that the ejecta have expanded into a very dense interstellar medium. The ejecta-dominated chemical compositions of the plasma indicate that the ambient materials should be highly homogeneous. We thus evaluate a simplified dynamical evolution model where an SNR was formed about 10,000 yr ago and expanded into an ambient medium with a homogeneous density of 103 cm-3. The model roughly reproduces most of the observed properties in the X-ray and radio wavelengths. A comparison with the radio observations requires the dense ambient medium to be ionized, but a luminous X-ray irradiator with an expected X-ray luminosity of ~1040 ergs s-1 is not currently present. The presence of the ionized gas may be explained if the massive black hole (MBH) associated with the compact, nonthermal radio source Sgr A* was bright in X-rays about 300 yr ago but is presently dim. It is possible that the dust/molecular ridge compressed by the forward shock of Sgr A East hit Sgr A* in the past, and the passage of the ridge may have supplied material to accrete onto the black hole in the past and may have removed material from the black hole vicinity, leading to its present quiescent state. This may be a specific example of the intimate relationship between an SNR and MBH accretion activity in galactic nuclei.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/34aa6e158964a74b980d506780df3c5ef8a7595a
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Astronomy and Astrophysics
Citations in the corpus
- Chandra X-Ray Spectroscopic Imaging of Sagittarius A* and the Central Parsec of the Galaxy (2001, background): “We propose here and in Maeda et al. (2002) that the X-ray luminosity of Sgr A* may have been significantly higher a few hundred years ago as the supernova blast wave swept through the position of the SMBH. Similarly, we have discovered bright clumps of X-ray emission located on opposite sides of…”
- A Deep Chandra Catalog of X-Ray Point Sources toward the Galactic Center (2003, background): “Chandra was the first instrument to resolve the X-ray emission from the accreting black hole Sgr A* from the surrounding early-type stars, the remnant of a 1052 erg explosion (Sgr A East; Maeda et al. 2002), and numerous filamentary features (Baganoff et al. 2001, 2003).”
- LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER (2011, background): “However, probably the foreground extinction towards Sgr A East and Sgr A* is not fully homogeneous.”
- Very high-energy gamma rays from the direction of Sagittarius A* (2004, background): “An obvious candidate for the proton accelerator could be the young (104 yr) and unusually powerful (total explosion energy 4× 1052 erg) supernova remnant Sgr A East (Maeda et al. 2002).”
- Stellar and wind properties of massive stars in the central parsec of the Galaxy (2006, methodology): “Finally, observations of K shell Fe lines by Chandra have been used by Maeda et al. (2002) to derive an iron content as large as 4 times solar for the H ii region SgrA East.”
- Detection of Sub-TeV Gamma Rays from the Galactic Center Direction by CANGAROO-II (2004, background): “INTRODUCTION Many observations have been made of the Galactic center (GC) region over a wide range of wavelengths (e.g., Pauls et al. 1976; Sofue et al. 1986; Pedlar et al. 1989; Koyama et al. 1996; Buckley et al. 1997; Purcell et al. 1997; Mayer-Hasselwander et al. 1998; Maeda et al. 2002).”
- Diffuse X-Ray Emission in a Deep Chandra Image of the Galactic Center (2004, background): “The differences in the soft emission is the most dramatic: it is lowest in the Northwest, Southeast, and Southwest, 50% higher in the region close to the Galactic center, a factor of 3 higher in the East, and a factor of 9 brighter in the Northeast.”
- Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole (2017, background): “The observed blue OB giants will eventually explode as SNe, and populate the Galactic Center with compact remnants (SNe remnants are still seen in the region, e.g. Maeda et al. 2002).”
- A Review of Bondi-Hoyle-Lyttleton Accretion (2004, background): “Maeda et al. (2002) studied the central portions of our Galaxy with Chandra.”