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Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations

This paper presents observations made by the Chandra X-ray Observatory on Sagittarius A* (Sgr A*) from 1999 to 2019. The X-ray spectra from 143 observations were analysed to investigate the X-ray evolution of Sgr A* throughout 20 years focusing on its key characteristics, i.e., the luminosities, col...

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Main Authors: Azizan, Aimi, Hamid, Muhammad Ezzat Abdul, Annuar, Adlyka
Format: Article
Published: Penerbit Universiti Kebangsaan Malaysia 2024
Subjects:
R Medicine (General)
Online Access:http://eprints.um.edu.my/47001/
https://doi.org/10.17576/jsm-2024-5304-13
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spelling my.um.eprints.470012025-01-08T09:05:33Z http://eprints.um.edu.my/47001/ Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations Azizan, Aimi Hamid, Muhammad Ezzat Abdul Annuar, Adlyka R Medicine (General) This paper presents observations made by the Chandra X-ray Observatory on Sagittarius A* (Sgr A*) from 1999 to 2019. The X-ray spectra from 143 observations were analysed to investigate the X-ray evolution of Sgr A* throughout 20 years focusing on its key characteristics, i.e., the luminosities, column density ( N H ), and photon index (F). In general, this study found that Sgr A* remained in a stable state throughout the observation period, with an average intrinsic X-ray luminosity in the 2 - 8 keV energy range of L 2-8 keV, int, all = 3.69 +/- 4.25 x 10 33 erg s -1 . This is consistent with the average observed X-ray luminosity, L 2-8 keV, obs, all = 2.24 +/- 2.12) x 10 33 erg s -1 . However, there were seven observations ( - 5%) that had intrinsic luminosities exceeding the estimated average value. The measured values of N H and F for all observations, remained consistent throughout the study with average values of N H meas = 0.90 +/- 0.35 x 10 23 cm -2 and F + 0 4 meas =1.90 +/- 0.6. This suggests that the variability in the observed luminosity was not caused by obscuration or significant changes in accretion rate. Additionally, this study also measured the highest 3 84 -0.37 X-ray luminosity for Sgr A*, L 2-8 keV, int = 3 3.84 84 -0.37 +0.46 x 10 34 erg s -1 on 14th September 2013. This finding is in line with the brightest flare ever observed in past studies. This was followed by an observation on 19th August 2019, with a luminosity of L 2-8 keV, int = 2.40 2 40 -0.36 +0.52 erg s -1 . This analysis provides a comprehensive overview of the evolution of Sgr A*'s emissions during the first two decades of Chandra `s operation and further enhances our understanding of this 2.40 0 36 +0.52 black hole. Penerbit Universiti Kebangsaan Malaysia 2024-04 Article PeerReviewed Azizan, Aimi and Hamid, Muhammad Ezzat Abdul and Annuar, Adlyka (2024) Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations. Sains Malaysiana, 53 (4). pp. 893-905. ISSN 0126-6039, DOI https://doi.org/10.17576/jsm-2024-5304-13 <https://doi.org/10.17576/jsm-2024-5304-13>. https://doi.org/10.17576/jsm-2024-5304-13 10.17576/jsm-2024-5304-13
institution Universiti Malaya
building UM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaya
content_source UM Research Repository
url_provider http://eprints.um.edu.my/
topic R Medicine (General)
spellingShingle R Medicine (General)
Azizan, Aimi
Hamid, Muhammad Ezzat Abdul
Annuar, Adlyka
Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
description This paper presents observations made by the Chandra X-ray Observatory on Sagittarius A* (Sgr A*) from 1999 to 2019. The X-ray spectra from 143 observations were analysed to investigate the X-ray evolution of Sgr A* throughout 20 years focusing on its key characteristics, i.e., the luminosities, column density ( N H ), and photon index (F). In general, this study found that Sgr A* remained in a stable state throughout the observation period, with an average intrinsic X-ray luminosity in the 2 - 8 keV energy range of L 2-8 keV, int, all = 3.69 +/- 4.25 x 10 33 erg s -1 . This is consistent with the average observed X-ray luminosity, L 2-8 keV, obs, all = 2.24 +/- 2.12) x 10 33 erg s -1 . However, there were seven observations ( - 5%) that had intrinsic luminosities exceeding the estimated average value. The measured values of N H and F for all observations, remained consistent throughout the study with average values of N H meas = 0.90 +/- 0.35 x 10 23 cm -2 and F + 0 4 meas =1.90 +/- 0.6. This suggests that the variability in the observed luminosity was not caused by obscuration or significant changes in accretion rate. Additionally, this study also measured the highest 3 84 -0.37 X-ray luminosity for Sgr A*, L 2-8 keV, int = 3 3.84 84 -0.37 +0.46 x 10 34 erg s -1 on 14th September 2013. This finding is in line with the brightest flare ever observed in past studies. This was followed by an observation on 19th August 2019, with a luminosity of L 2-8 keV, int = 2.40 2 40 -0.36 +0.52 erg s -1 . This analysis provides a comprehensive overview of the evolution of Sgr A*'s emissions during the first two decades of Chandra `s operation and further enhances our understanding of this 2.40 0 36 +0.52 black hole.
format Article
author Azizan, Aimi
Hamid, Muhammad Ezzat Abdul
Annuar, Adlyka
author_facet Azizan, Aimi
Hamid, Muhammad Ezzat Abdul
Annuar, Adlyka
author_sort Azizan, Aimi
title Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
title_short Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
title_full Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
title_fullStr Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
title_full_unstemmed Evolution of Sagittarius A* X-Ray Emission between 1999 and 2019 Based on Chandra X-Ray Observatory Observations
title_sort evolution of sagittarius a* x-ray emission between 1999 and 2019 based on chandra x-ray observatory observations
publisher Penerbit Universiti Kebangsaan Malaysia
publishDate 2024
url http://eprints.um.edu.my/47001/
https://doi.org/10.17576/jsm-2024-5304-13
_version_ 1821105751971594240
score 13.2353115

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