TY  - JOUR
A1  - Torrejon, J. M.
A1  - Reig, Pablo
A1  - Fürst, F.
A1  - Martinez-Chicharro, M.
A1  - Postnov, K.
A1  - Oskinova, Lida
T1  - NuSTAR rules out a cyclotron line in the accreting magnetar candidate 4U2206+54
JF  - Monthly notices of the Royal Astronomical Society
N2  - Based on our new NuSTAR X-ray telescope data, we rule out any cyclotron line up to 60 keV in the spectra of the high-mass X-ray binary 4U2206+54. In particular, we do not find any evidence of the previously claimed line around 30 keV, independently of the source flux, along the spin pulse. The spin period has increased significantly, since the last observation, up to 5750 +/- 10 s, confirming the rapid spin-down rate (nu)over dot = -1.8 x 10(-14) Hz s(-1). This behaviour might be explained by the presence of a strongly magnetized neutron star (B-s > several times 10(13) G) accreting from the slow wind of its main-sequence O9.5 companion.
KW  - Stars: individual: 4U2206+54, BD+53 2790
KW  - X-rays: binaries
Y1  - 2018
U6  - https://doi.org/10.1093/mnras/sty1628
SN  - 0035-8711
SN  - 1365-2966
VL  - 479
IS  - 3
SP  - 3366
EP  - 3372
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Oskinova, Lida
A1  - Bik, A.
A1  - Mas-Hesse, J. M.
A1  - Hayes, M.
A1  - Adamo, A.
A1  - Östlin, Göran
A1  - Fürst, F.
A1  - Otí-Floranes, H.
T1  - ULX contribution to stellar feedback
BT  - an intermediate-mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO338-4
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last <40 Myr and contains some of the most massive super star clusters in the nearby Universe. Given its starburst age and its star-formation rate, ESO 338-4 is one of the most efficient nearby manufactures of neutron stars and black holes, hence providing an excellent laboratory for feedback studies. Aims. We aim to use X-ray observations with the largest modern X-ray telescopes XMM-Newton and Chandra to unveil the most luminous accreting neutron stars and black holes in ESO 338-4. Methods. We compared X-ray images and spectra with integral field spectroscopic observations in the optical to constrain the nature of strong X-ray emitters. Results. X-ray observations uncover three ultraluminous X-ray sources (ULXs) in ESO 338-4. The brightest among them, ESO 338 X-1, has X-ray luminosity in excess of 10(40) erg s(-1). We speculate that ESO 338-4 X-1 is powered by accretion on an intermediate-mass (greater than or similar to 300 M-circle dot)black hole. We show that X-ray radiation from ULXs and hot superbubbles strongly contributes to He II ionization and general stellar feedback in this template starburst galaxy.
KW  - galaxies: dwarf
KW  - galaxies: individual: ESO 338-4
KW  - X-rays: binaries
KW  - X-rays: ISM
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201935414
SN  - 1432-0746
VL  - 627
PB  - EDP Sciences
CY  - Les Ulis
ER  -