2002ApJ...570..671M


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.21CEST14:53:39

2002ApJ...570..671M - Astrophys. J., 570, 671-687 (2002/May-2)

A Chandra study of Sagittarius A East: a supernova remnant regulating the activity of our Galactic Center.

MAEDA Y., BAGANOFF F.K., FEIGELSON E.D., MORRIS M., BAUTZ M.W., BRANDT W.N., BURROWS D.N., DOTY J.P., GARMIRE G.P., PRAVDO S.H., RICKER G.R. and TOWNSLEY L.K.

Abstract (from CDS):

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 ∼1x1023 H.cm–2, luminosity ∼8x1034 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.

Abstract Copyright:

Journal keyword(s): Galaxy: Center - ISM: Individual: Name: Sagittarius A East - ISM: Supernova Remnants - X-Rays: ISM

Simbad objects: 27

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Number of rows : 27

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 SNR G119.5+10.2 SNR 00 06.6 +72 47           ~ 236 1
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9557 1
3 SNR G132.6+01.5 SNR 02 17 40 +62 45.0           ~ 158 0
4 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14989 1
5 IC 443 SNR 06 18 02.7 +22 39 36           ~ 1109 1
6 NAME MSH 11-61A SNR 10 59 25.36 -61 18 42.6           ~ 156 0
7 SNR G327.4+00.4 SNR 15 48 20 -53 49.0           ~ 84 0
8 SNR G327.1-01.1 SNR 15 54 32.3 -55 03 44           ~ 84 1
9 SNR G359.1-00.5 Rad 17 45 30 -29 57.0           ~ 158 1
10 NAME Sgr A West HII 17 45 39.4 -29 00 24           ~ 352 0
11 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3516 3
12 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11758 0
13 NAME Sgr A East Rad 17 45 41 -29 00.8           ~ 445 2
14 GCM -0.02 -0.07 MoC 17 45 50.4 -28 59 06           ~ 141 0
15 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1943 1
16 SNR G006.4-00.1 SNR 18 01 22.7 -23 17 20           ~ 658 1
17 3C 391.0 Rad 18 49 23.3 -00 55 38           ~ 320 2
18 SNR G033.6+00.1 SNR 18 52 29.000 +00 38 42.00           ~ 242 1
19 SNR G034.6-00.5 SNR 18 56 10.650 +01 13 21.30           ~ 831 2
20 W 49b SNR 19 11 09.000 +09 06 24.00           ~ 398 1
21 SNR G049.1-00.1 SNR 19 23 19.300 +14 09 21.00           ~ 243 0
22 SNR G053.6-02.2 SNR 19 38.8 +17 14           ~ 137 0
23 SNR G082.2+05.3 SNR 20 19.0 +45 30           ~ 86 0
24 SNR G089.0+04.7 SNR 20 45.0 +50 35           ~ 197 0
25 SNR G093.7-00.2 SNR 21 29.3 +50 50           ~ 65 1
26 CTB 104 Rad 21 32.1 +50 51           ~ 16 1
27 CTB 1 SNR 23 59 13 +62 26.2           ~ 141 0

    Equat.    Gal    SGal    Ecl

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2020.10.21-14:53:39

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