Simultaneous X-ray and optical observations of GX 339-4 in an X-ray high state

Makishima, Kazuo; Maejima, Yuji; Mitsuda, K.; Bradt, H.; Remillard, Ron; Tuohy, I. R.; Hōshi, Reiun; Nakagawa, Michiko

doi:10.1086/164534

Cited by 522 publications

(485 citation statements)

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“…These results significantly reinforce the BH scenario of ULXs since the MCD model can explain the soft X-ray spectra of Galactic/Magellanic black hole binaries (BHBs) in the "soft (or high) state" (e.g., Makishima et al 1986;Ebisawa et al 1993;Dotani et al 1997;Kubota et al 1998;Feroci et al 1999;Paper I).…”

supporting

confidence: 61%

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

Kubota

Mizuno

Makishima

et al. 2001

The Astrophysical Journal

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114

124

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Two ASCA observations were made of two ultraluminous compact X-ray sources (ULXs) in the spiral galaxy IC 342. In the 1993 observation, source 2 showed a 0.5-10 keV luminosity of ergs s (assuming a 39 Ϫ16 # 10 distance of 4.0 Mpc) and a hard power-law spectrum of photon index ∼1.4. As already reported, source 1 was ∼3 times brighter on that occasion and exhibited a soft spectrum represented by a multicolor disk model with an inner-disk temperature of ∼1.8 keV. The second observation, made in 2000 February, revealed that source 1 had made a transition into a hard spectral state, while source 2 made a transition into a soft spectral state. The ULXs are therefore inferred to exhibit two distinct spectral states, and they sometimes make transitions between them. These results significantly reinforce the scenario that describes ULXs as mass-accreting black holes.

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supporting

confidence: 61%

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

Kubota

Mizuno

Makishima

et al. 2001

The Astrophysical Journal

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114

124

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“…This broken power law is modified by a high-energy cutoff, by an Fe Kα-line modeled with a Gaussian at ∼6.4 keV, and by absorption. A multitemperature disk (diskbb, Mitsuda et al 1984;Makishima et al 1986) is added to the model where it improves the χ 2 by more than 5% except in seven cases where the X-ray timing behavior and the correlation between Γ 1 and Γ 2 strongly prefer the model without a disk (Grinberg et al 2014 Figure 3 shows that the model offers a very good description of the spectrum. As in Grinberg et al (2013), we use Γ 1 -based state definitions derived from spectral and timing properties of Cyg X-1: the source is in hard state if Γ 1 ≤ 2.0, in the intermediate state if 2.0 < Γ 1 ≤ 2.5, and in the soft state if 2.5 < Γ 1 .…”

Section: Data and Spectral Analysismentioning

confidence: 99%

Long term variability of Cygnus X-1

Grinberg

Leutenegger

Hell

et al. 2015

A&A

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Binary systems with an accreting compact object offer a unique opportunity to investigate the strong, clumpy, line-driven winds of early-type supergiants by using the compact object's X-rays to probe the wind structure. We analyze the two-component wind of HDE 226868, the O9.7Iab giant companion of the black hole Cyg X-1, using 4.77 Ms Rossi X-ray Timing Explorer (RXTE) observations of the system taken over the course of 16 years. Absorption changes strongly over the 5.6 d binary orbit, but also shows a large scatter at a given orbital phase, especially at superior conjunction. The orbital variability is most prominent when the black hole is in the hard X-ray state. Our data are poorer for the intermediate and soft state, but show signs for orbital variability of the absorption column in the intermediate state. We quantitatively compare the data in the hard state to a toy model of a focussed Castor-AbbottKlein wind: as it does not incorporate clumping, the model does not describe the observations well. A qualitative comparison to a simplified simulation of clumpy winds with spherical clumps shows good agreement in the distribution of the equivalent hydrogen column density for models with a porosity length on the order of the stellar radius at inferior conjunction; we conjecture that the deviations between data and model at superior conjunction could either be due to lack of a focussed wind component in the model or to a more complicated clump structure.

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“…Red data points correspond to ULX-1 in eclipse, green data points to ULX-1 out of eclipse, the single cyan data point to ULX-2 in eclipse and blue data points to ULX-2 out of eclipse. Colors have been corrected for the change in sensitivity of the ACIS-S detector over the years (Section 4.3, Table 4) We started by fitting single-component disk models: TBabs×TBabs×diskbb for a standard disk (Mitsuda et al 1984;Makishima et al 1986), and TBabs ×TBabs × diskpbb for a slim disk (Kubota et al 2005). They fare relatively better (c » n 1.6 2 and c » n 1.5 2 , respectively) than a power-law model, but they are still not good fits.…”

Section: Spectral Models For Ulx-1mentioning

confidence: 99%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

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We present the discovery, from archival Chandra and XMM-Newton data, of X-ray eclipses in two ultraluminous X-ray sources (ULXs), located in the same region of the galaxy M51: CXOM51 J132940.0+471237 (ULX-1, for simplicity) and CXOM51 J132939.5+471244 (ULX-2). Three eclipses were detected for ULX-1 and two for ULX-2. The presence of eclipses puts strong constraints on the viewing angle, suggesting that both ULXs are seen almost edge-on and are certainly not beamed toward us. Despite the similar viewing angles and luminosities ( »Ĺ 2 10 X 39 erg s −1 in the 0.3-8 keV band for both sources), their X-ray properties are different. ULX-1 has a soft spectrum, well fitted by Comptonization emission from a medium with electron temperature » kT 1 keV e . ULX-2 is harder, well fitted by a slim disk with » kT 1.5 in -1.8 keV and normalization consistent with a ∼10 M e black hole. ULX-1 has a significant contribution from multi-temperature thermal-plasma emission ( »Ĺ 2 10 X,mekal 38 erg s −1 ). About 10% of this emission remains visible during the eclipses, proving that the emitting gas comes from a region slightly more extended than the size of the donor star. From the sequence and duration of the Chandra observations in and out of eclipse, we constrain the binary period of ULX-1 to be either »6.3 days, or ≈12.5-13 days. If the donor star fills its Roche lobe (a plausible assumption for ULXs), both cases require an evolved donor, most likely a blue supergiant, given the young age of the stellar population in that Galactic environment.

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Simultaneous X-ray and optical observations of GX 339-4 in an X-ray high state

Cited by 522 publications

References 0 publications

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

Long term variability of Cygnus X-1

Two Eclipsing Ultraluminous X-Ray Sources in M51

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