Comprehensive analysis of the transient X-ray pulsar MAXI J1409−619

ABSTRACT We probe the properties of the transient X-ray pulsar MAXI J1409−619 through RXTE and Swift follow-up observations of the outburst in 2010. We are able to phase-connect the pulse arrival times for the 25 d episode during the outburst. We suggest that either an orbital model (with Porb ≃ 14....

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Veröffentlicht in:Monthly notices of the Royal Astronomical Society 2020-08, Vol.496 (2), p.1768-1783
Hauptverfasser: Dönmez, Ç K, Serim, M M, İnam, S Ç, Şahiner, Ş, Serim, D, Baykal, A
Format: Artikel
Sprache:eng
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Zusammenfassung:ABSTRACT We probe the properties of the transient X-ray pulsar MAXI J1409−619 through RXTE and Swift follow-up observations of the outburst in 2010. We are able to phase-connect the pulse arrival times for the 25 d episode during the outburst. We suggest that either an orbital model (with Porb ≃ 14.7(4) d) or a noise process due to random torque fluctuations (with Sr ≈ 1.3 × 10−18 Hz2 s−2 Hz−1) is plausible to describe the residuals of the timing solution. The frequency derivatives indicate a positive torque–luminosity correlation, which implies temporary accretion disc formation during the outburst. We also discover several quasi-periodic oscillations in company with their harmonics whose centroid frequencies decrease as the source flux decays. The variation of the pulsed fraction and spectral power-law index of the source with X-ray flux is interpreted as the sign of transition from a critical to a sub-critical accretion regime at the critical luminosity within the range of 6 × 1037–1.2 × 1038 erg s−1. Using pulse-phase-resolved spectroscopy, we show that the phases with higher flux tend to have lower photon indices, indicating that the polar regions produce spectrally harder emission.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/staa1562