2012A&A...542L..28K


Query : 2012A&A...542L..28K

2012A&A...542L..28K - Astronomy and Astrophysics, volume 542, L28-28 (2012/6-1)

Outburst of GX 304-1 monitored with INTEGRAL: positive correlation between the cyclotron line energy and flux.

KLOCHKOV D., DOROSHENKO V., SANTANGELO A., STAUBERT R., FERRIGNO C., KRETSCHMAR P., CABALLERO I., WILMS J., KREYKENBOHM I., POTTSCHMIDT K., ROTHSCHILD R.E., WILSON-HODGE C.A. and PUEHLHOFER G.

Abstract (from CDS):

X-ray spectra of many accreting pulsars exhibit significant variations as a function of flux and thus of mass accretion rate. In some of these pulsars, the centroid energy of the cyclotron line(s), which characterizes the magnetic field strength at the site of the X-ray emission, has been found to vary systematically with flux. GX 304-1 is a recently established cyclotron line source with a line energy around 50keV. Since 2009, the pulsar shows regular outbursts with the peak flux exceeding one Crab. We analyze the INTEGRAL observations of the source during its outburst in January-February 2012. The observations covered almost the entire outburst, allowing us to measure the source's broad-band X-ray spectrum at different flux levels. We report on the variations in the spectral parameters with luminosity and focus on the variations in the cyclotron line. The centroid energy of the line is found to be positively correlated with the luminosity. We interpret this result as a manifestation of the local sub-Eddington (sub-critical) accretion regime operating in the source.

Abstract Copyright:

Journal keyword(s): X-rays: binaries - stars: neutron - accretion, accretion disks

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* V635 Cas HXB 01 18 31.9704429246 +63 44 33.071137750 17.05 16.64 15.19 14.34 13.22 B0.2Ve 676 0
2 V* BQ Cam HXB 03 34 59.9116460415 +53 10 23.296351781   17.16 15.42 14.26 13.04 O8.5Ve 413 1
3 HD 245770 HXB 05 38 54.5749436467 +26 18 56.839215267 9.30 9.84 9.39 8.77 8.30 O9/B0III/Ve 891 0
4 V* V850 Cen HXB 13 01 17.0966951298 -61 36 06.636402972   15.6 14.40     B2Vne 285 0
5 V* HZ Her LXB 16 57 49.8110797681 +35 20 32.487435684 11.90 14.89 13.63 13.88   B3/6ep 1958 0

    Equat.    Gal    SGal    Ecl

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2021.07.25-17:20:25

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