2007A&A...466L..17C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.08CEST07:11:32

2007A&A...466L..17C - Astronomy and Astrophysics, volume 466, L17-20 (2007/5-1)

A 33 hour period for the Wolf-Rayet/black hole X-ray binary candidate NGC 300 X-1.

CARPANO S., POLLOCK A.M.T., PRESTWICH A., CROWTHER P., WILMS J., YUNGELSON L. and EHLE M.

Abstract (from CDS):

NGC 300 X-1 is the second extragalactic candidate, after IC 10 X-1, in the rare class of Wolf-Rayet/compact object X-ray binary systems exemplified in the Galaxy by Cyg X-3. From a theoretical point of view, accretion onto a black hole in a detached system is possible for large orbital periods only if the mass of the relativistic object is high or the velocity of the accreted wind is low. We analysed a 2 week SWIFT XRT light curve of NGC 300 X-1 and searched for periodicities. Period searches were made using Lomb-Scargle periodogram analysis. We evaluated the confidence level using Monte Carlo simulations.A period of 32.8±0.4h (3σ error) was found for NGC 300 X-1 with a confidence level >99%. Furthermore, we confirm the high irregular variability during the high flux level, as already observed in the XMM-Newton observations of the source. A folded XMM-Newton light curve is shown, with a profile that is in agreement with SWIFT . The mean absorbed X-ray luminosity in the SWIFT observations was 1.5x1038erg/s, close to the value derived from the XMM-Newton data. While Cyg X-3 has a short period of 4.8 h, the period of NGC 300 X-1 is very close to that of IC 10 X-1 (34.8±0.9h). These are likely orbital periods. Possibility of formation of accretion disk for such high orbital periods strongly depends on the terminal velocity of the Wolf-Rayet star wind and black-hole mass. While low masses are possible for wind velocities ≲1000km/s, these increase to several tens of solar masses for velocities >1600km/s and no accretion disk may form for terminal velocities larger than 1900km/s.

Abstract Copyright:

Journal keyword(s): X-rays: individual: NGC 300 X-1 - X-rays: binaries - stars: Wolf-Rayet

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 IC 10 G 00 20 23.16 +59 17 34.7   13.6 9.5     ~ 1008 0
2 NAME IC 10 X-1 HXB 00 20 29.09 +59 16 51.9           ~ 148 0
3 [MPG2004] 57 WR* 00 54 41.82 -37 38 36.5   18.93 18.92     ~ 4 0
4 NGC 300 GiG 00 54 53.4460065856 -37 41 03.182962667 8.83 8.69 8.13 7.46   ~ 1305 2
5 NAME NGC 300 X-1 HXB 00 55 09.990 -37 42 12.16     22.44     WNE 103 1
6 LS 2173 WR* 11 07 54.0718353772 -61 27 40.801628087   16.44 14.50 14.29   WC5+OB? 25 0
7 V* V1521 Cyg HXB 20 32 25.78 +40 57 27.9           WN4/5-6/7 1765 2

    Equat.    Gal    SGal    Ecl

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2020.07.08-07:11:32

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