Details

Autor(en) / Beteiligte

• Del Santo, M
• Pinto, C
• Marino, A
• D’Aì, A
• Petrucci, P-O
• Malzac, J
• Ferreira, J
• Pintore, F
• Motta, S E
• Russell, T D
• Segreto, A
• Sanna, A

Titel

An ultrafast outflow in the black hole candidate MAXI J1810−222?

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2023-07, Vol.523 (1), p.L15-L20

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• ABSTRACT The transient X-ray source MAXI J1810−222 was discovered in 2018 and has been active ever since. A long combined radio and X-ray monitoring campaign was performed with Australia Telescope Compact Array and Swift, respectively. It has been proposed that MAXI J1810−222 is a relatively distant black hole X-ray binary, albeit showing a very peculiar outburst behaviour. Here, we report on the spectral study of this source making use of a large sample of NICER observations performed between 2019 February and 2020 September. We detected a strong spectral absorption feature at ∼1 keV, which we have characterized with a physical photoionization model. Via a deep scan of the parameters space, we obtained evidence for a spectral-state dependent outflow, with mildly relativistic speeds. In particular, the soft and intermediate states point to a hot plasma outflowing at 0.05–0.15c. This speeds rule-out thermal winds and hence, they suggest that such outflows could be radiation pressure or (most likely) magnetically driven winds. Our results are crucial to test current theoretical models of wind formation in X-ray binaries.