2023A&A...671A..55A


Query : 2023A&A...671A..55A

2023A&A...671A..55A - Astronomy and Astrophysics, volume 671A, 55 (2023/3-1)

Study of the excess Fe XXV line emission in the central degrees of the Galactic centre using XMM-Newton data.

ANASTASOPOULOU K., PONTI G., SORMANI M.C., LOCATELLI N., HABERL F., MORRIS M.R., CHURAZOV E.M., SCHODEL R., MAITRA C., CAMPANA S., DI TEODORO E.M., JIN C., KHABIBULLIN I., MONDAL S., SASAKI M., ZHANG Y. and ZHENG X.

Abstract (from CDS):

The diffuse Fe XXV (6.7 keV) line emission observed in the Galactic ridge is widely accepted to be produced by a superposition of a large number of unresolved X-ray point sources. In the very central degrees of our Galaxy, however, the existence of an extremely hot (∼7 keV) diffuse plasma is still under debate. In this work we measure the Fe XXV line emission using all available XMM-Newton observations of the Galactic centre (GC) and inner disc (-10° < < 10°, -2° < b < 2°). We use recent stellar mass distribution models to estimate the amount of X-ray emission originating from unresolved point sources, and find that within a region of = ±1° and b = ±0.25° the 6.7keV emission is 1.3-1.5 times in excess of what is expected from unresolved point sources. The excess emission is enhanced towards regions where known supernova remnants are located, suggesting that at least a part of this emission is due to genuine diffuse very hot plasma. If the entire excess is due to very hot plasma, an energy injection rate of at least ∼6 × 1040 erg s–1 is required, which cannot be provided by the measured supernova explosion rate or past Sgr A* activity alone. However, we find that almost the entire excess we observe can be explained by assuming GC stellar populations with iron abundances ∼1.9 times higher than those in the bar/bulge, a value that can be reproduced by fitting diffuse X-ray spectra from the corresponding regions. Even in this case, a leftover X-ray excess is concentrated within = ±0.3° and b = ±0.15°, corresponding to a thermal energy of ∼2 × 1052 erg, which can be reproduced by the estimated supernova explosion rate in the GC. Finally we discuss a possible connection to the observed GC Fermi-LAT excess.

Abstract Copyright: © The Authors 2023

Journal keyword(s): Galaxy: bulge - Galaxy: center - Galaxy: disk - X-rays: general - X-rays: ISM

VizieR on-line data: <Available at CDS (J/A+A/671/A55): tableb1.dat>

Simbad objects: 24

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Number of rows : 24
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 M 1 SNR 05 34 30.9 +22 00 53           ~ 6202 1
2 M 82 AGN 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5869 6
3 SNR G352.7-00.1 Rad 17 27 43 -35 06.5           ~ 72 1
4 IGR J17354-3255 HXB 17 35 27.6058982616 -32 55 54.425912052           O9Iab 52 1
5 NAME Great Annihilator LXB 17 43 54.83 -29 44 42.6           ~ 674 1
6 KS 1741-293 LXB 17 44 51.63 -29 20 42.8           ~ 102 0
7 NAME Fermi Bubbles bub 17 45 -29.0           ~ 440 0
8 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14463 0
9 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4400 3
10 0FGL J1746.0-2900 gam 17 45 41 -29 00.8           ~ 494 2
11 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 739 0
12 2E 3943 LXB 17 46 05.20 -29 30 53.3           ~ 209 1
13 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 527 0
14 2E 3944 LXB 17 46 21.09 -28 43 42.3     12.50     ~ 121 0
15 CXO J174621.6-285257 X 17 46 21.51 -28 52 56.5           ~ 23 0
16 GAL 000.61+00.01 SNR 17 47.0 -28 25           ~ 12 0
17 [KC97c] G000.9+00.1 HII 17 47 16.3 -28 08 41           ~ 2 0
18 AX J1747.4-3000 LXB 17 47 25.90 -30 00 02.0           ~ 108 0
19 [CHM2006] Candidate 1b LXB 17 49 38.039 -28 21 17.50           ~ 78 0
20 SNR G006.4-00.1 SNR 18 00 31.2011719 -23 25 48.001099           ~ 738 1
21 M 2 GlC 21 33 27.02 -00 49 23.7     6.25     ~ 1032 1
22 NAME Galactic Ridge ? ~ ~           ~ 500 1
23 NAME Galactic Bulge reg ~ ~           ~ 4309 0
24 NAME Galactic Bar reg ~ ~           ~ 1224 0

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