TY  - JOUR
A1  - Martinez-Chicharro, M.
A1  - Torrejon, J. M.
A1  - Oskinova, Lida
A1  - Furst, F.
A1  - Postnov, K.
A1  - Rodes-Roca, J. J.
A1  - Hainich, Rainer
A1  - Bodaghee, A.
T1  - Evidence of Compton cooling during an X-ray flare supports a neutron star nature of the compact object in 4U1700-37
JF  - Monthly notices of the Royal Astronomical Society
N2  - Based on new Chandra X-ray telescope data, we present empirical evidence of plasma Compton cooling during a flare in the non-pulsating massive X-ray binary 4U1700-37. This behaviour might be explained by quasi-spherical accretion on to a slowly rotating magnetized neutron star (NS). In quiescence, the NS in 4U1700-37 is surrounded by a hot radiatively cooling shell. Its presence is supported by the detection of mHz quasi-periodic oscillations likely produced by its convection cells. The high plasma temperature and the relatively low X-ray luminosity observed during the quiescence, point to a small emitting area similar to 1 km, compatible with a hotspot on an NS surface. The sudden transition from a radiative to a significantly more efficient Compton cooling regime triggers an episode of enhanced accretion resulting in a flare. During the flare, the plasma temperature drops quickly. The predicted luminosity for such transitions, similar to 3 x 10(35) erg s(-1), is very close to the luminosity of 4U1700-37 during quiescence. The transition may be caused by the accretion of a clump in the stellar wind of the donor star. Thus, a magnetized NS nature of the compact object is strongly favoured.
KW  - stars: individual: 4U1700-37
KW  - V*V884 Sco
KW  - X-rays: binaries
Y1  - 2017
U6  - https://doi.org/10.1093/mnrasl/slx165
SN  - 0035-8711
SN  - 1365-2966
VL  - 473
IS  - 1
SP  - L74
EP  - L78
PB  - Oxford Univ. Press
CY  - Oxford
ER  -