Relatively few X-ray sources are known that have low-mass galaxies as hosts. This is an important restriction on studies of active galactic nuclei (AGNs), hence black holes, and of X-ray binaries (XRBs) in low-mass galaxies; addressing it requires very large samples of both galaxies and X-ray sources. Here, we have matched the X-ray point sources found in the XXL-N field of the XXL survey (with an X-ray flux limit of ∼6 × 10-15 erg s-1 cm-2 in the [0.5-2] keV band) to galaxies with redshifts from the Galaxy And Mass Assembly (GAMA) G02 survey field (down to a magnitude limit r = 19.8) in order to search for AGNs and XRBs in GAMA galaxies, particularly those of low optical luminosity or stellar mass (fainter than Mr =-19 or M∗ ≲ 109.5, M⊙). Out of a total of 1200 low-mass galaxies in the overlap region, we find a total of 28 potential X-ray source hosts, though this includes possible background contaminants. From a combination of photometry (optical and infrared colours), positional information, and optical spectra, we deduce that most of the ∼20 X-ray sources genuinely in low-mass galaxies are high-mass X-ray binaries in star-forming galaxies. None of the matched sources in a low-mass galaxy has a BPT classification as an AGN, and even ignoring this requirement, none passes both criteria of close match between the X-ray source position and optical galaxy centre (separation ≤3 arcsec) and high [O iii] line luminosity (above 1040.3 erg s-1).

Nwaokoro E., Phillipps S., Young A.J., Baldry I., Bongiorno A., Bremer M.N., et al. (2021). GAMA/XXL: X-ray point sources in low-luminosity galaxies in the GAMA G02/XXL-N field. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 502(2), 3101-3112 [10.1093/mnras/stab242].

GAMA/XXL: X-ray point sources in low-luminosity galaxies in the GAMA G02/XXL-N field

Vignali C.
Membro del Collaboration Group
2021

Abstract

Relatively few X-ray sources are known that have low-mass galaxies as hosts. This is an important restriction on studies of active galactic nuclei (AGNs), hence black holes, and of X-ray binaries (XRBs) in low-mass galaxies; addressing it requires very large samples of both galaxies and X-ray sources. Here, we have matched the X-ray point sources found in the XXL-N field of the XXL survey (with an X-ray flux limit of ∼6 × 10-15 erg s-1 cm-2 in the [0.5-2] keV band) to galaxies with redshifts from the Galaxy And Mass Assembly (GAMA) G02 survey field (down to a magnitude limit r = 19.8) in order to search for AGNs and XRBs in GAMA galaxies, particularly those of low optical luminosity or stellar mass (fainter than Mr =-19 or M∗ ≲ 109.5, M⊙). Out of a total of 1200 low-mass galaxies in the overlap region, we find a total of 28 potential X-ray source hosts, though this includes possible background contaminants. From a combination of photometry (optical and infrared colours), positional information, and optical spectra, we deduce that most of the ∼20 X-ray sources genuinely in low-mass galaxies are high-mass X-ray binaries in star-forming galaxies. None of the matched sources in a low-mass galaxy has a BPT classification as an AGN, and even ignoring this requirement, none passes both criteria of close match between the X-ray source position and optical galaxy centre (separation ≤3 arcsec) and high [O iii] line luminosity (above 1040.3 erg s-1).
2021
Nwaokoro E., Phillipps S., Young A.J., Baldry I., Bongiorno A., Bremer M.N., et al. (2021). GAMA/XXL: X-ray point sources in low-luminosity galaxies in the GAMA G02/XXL-N field. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 502(2), 3101-3112 [10.1093/mnras/stab242].
Nwaokoro E.; Phillipps S.; Young A.J.; Baldry I.; Bongiorno A.; Bremer M.N.; Brown M.J.I.; Chiappetti L.; De Propris R.; Driver S.P.; Elyiv A.; Fotopo...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/863284
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