INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE

Sinan Allak; Aysun Akyüz

doi:10.18038/estubtda.1551932

TR EN

INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE

Abstract

This study investigates the X-ray and optical properties of 29 X-ray sources within the NGC 7552 galaxy, using Chandra, Swift X-Ray Telescope (Swift-XRT) data, and Hubble Space Telescope (HST). A significant finding was the identification of a new ultraluminous X-ray source (ULX-3) with an X-ray luminosity, LX 〖≈10〗^39 erg s^(-1) making it the third ULX identified in this galaxy. The spectral analysis of ULX-3 suggests it could be a stellar-mass black hole with an estimated mass of around 8 solar masses (M_⊙). Nearly half of the observed X-ray binaries (XRBs) were classified as transient or variable. Variability studies revealed that ULX-1 exhibited significant long-term variability in Chandra data, while ULX-2 remained stable in both Chandra and Swift-XRT observations. ULX-3 showed no significant variability in Chandra data, indicating steady emissions during the observation period. The analysis of the X-ray energy spectra for ULX-1, ULX-2, and ULX-3 showed that power-law models best described their spectra. These findings suggest that the ULXs have a hard spectral structure, commonly linked to X-ray emissions from compact objects such as black holes or neutron stars. Optical counterparts were also identified for several XRBs, including ULX-1, ULX-2, and ULX-3, most of which exhibit faint optical magnitudes (mV >22 mag) characteristic of ULX systems.

Keywords

Ultraluminous X-ray Sources (ULXs), X-ray Binaries, Optical Counterparts of ULXs, NGC 7552

INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE

Abstract

This study investigates the X-ray and optical properties of 29 X-ray sources within the NGC 7552 galaxy, using Chandra, Swift X-Ray Telescope (Swift-XRT) data, and Hubble Space Telescope (HST). A significant finding was the identification of a new ultraluminous X-ray source (ULX-3) with an X-ray luminosity, LX 〖≈10〗^39 erg s^(-1) making it the third ULX identified in this galaxy. The spectral analysis of ULX-3 suggests it could be a stellar-mass black hole with an estimated mass of around 8 solar masses (M_⊙). Nearly half of the observed X-ray binaries (XRBs) were classified as transient or variable. Variability studies revealed that ULX-1 exhibited significant long-term variability in Chandra data, while ULX-2 remained stable in both Chandra and Swift-XRT observations. ULX-3 showed no significant variability in Chandra data, indicating steady emissions during the observation period. The analysis of the X-ray energy spectra for ULX-1, ULX-2, and ULX-3 showed that power-law models best described their spectra. These findings suggest that the ULXs have a hard spectral structure, commonly linked to X-ray emissions from compact objects such as black holes or neutron stars. Optical counterparts were also identified for several XRBs, including ULX-1, ULX-2, and ULX-3, most of which exhibit faint optical magnitudes (mV >22 mag) characteristic of ULX systems.

Keywords

Ultraluminous X-ray Sources (ULXs), X-ray Binaries, Optical Counterparts of ULXs, NGC 7552

Supporting Institution

Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Project Number

122C183

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Details

Primary Language

English

Subjects

High Energy Astrophysics and Galactic Cosmic Rays

Journal Section

Research Article

Authors

Sinan Allak ^*
0000-0001-7093-1079
Türkiye

Aysun Akyüz
0000-0001-9533-9805
Türkiye

Publication Date

March 25, 2025

Submission Date

September 17, 2024

Acceptance Date

January 2, 2025

Published in Issue

Year 2025 Volume: 26 Number: 1

DOI

https://doi.org/10.18038/estubtda.1551932

IZ

https://izlik.org/JA96YG74XC

APA

Allak, S., & Akyüz, A. (2025). INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE. Eskişehir Technical University Journal of Science and Technology A - Applied Sciences and Engineering, 26(1), 45-59. https://doi.org/10.18038/estubtda.1551932

AMA

1.Allak S, Akyüz A. INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE. Estuscience - Se. 2025;26(1):45-59. doi:10.18038/estubtda.1551932

Chicago

Allak, Sinan, and Aysun Akyüz. 2025. “INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE”. Eskişehir Technical University Journal of Science and Technology A - Applied Sciences and Engineering 26 (1): 45-59. https://doi.org/10.18038/estubtda.1551932.

EndNote

Allak S, Akyüz A (March 1, 2025) INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE. Eskişehir Technical University Journal of Science and Technology A - Applied Sciences and Engineering 26 1 45–59.

IEEE

[1]S. Allak and A. Akyüz, “INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE”, Estuscience - Se, vol. 26, no. 1, pp. 45–59, Mar. 2025, doi: 10.18038/estubtda.1551932.

ISNAD

Allak, Sinan - Akyüz, Aysun. “INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE”. Eskişehir Technical University Journal of Science and Technology A - Applied Sciences and Engineering 26/1 (March 1, 2025): 45-59. https://doi.org/10.18038/estubtda.1551932.

JAMA

1.Allak S, Akyüz A. INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE. Estuscience - Se. 2025;26:45–59.

MLA

Allak, Sinan, and Aysun Akyüz. “INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE”. Eskişehir Technical University Journal of Science and Technology A - Applied Sciences and Engineering, vol. 26, no. 1, Mar. 2025, pp. 45-59, doi:10.18038/estubtda.1551932.

Vancouver

1.Sinan Allak, Aysun Akyüz. INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE. Estuscience - Se. 2025 Mar. 1;26(1):45-59. doi:10.18038/estubtda.1551932

INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE

Abstract

Keywords

INVESTIGATION OF X-RAY SOURCES IN NGC 7552: IDENTIFICATION OF A NEW ULX CANDIDATE

Abstract

Keywords

Supporting Institution

Project Number

References

Details

Primary Language

Subjects

Journal Section

Authors

Publication Date

Submission Date

Acceptance Date

Published in Issue

DOI

IZ

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