Slim-Disk Model for Ultraluminous X-Ray Sources

By K. Watarai, T. Mizuno, S. Mineshige. 2000

155 citations recorded by the source corpus.

The ultraluminous X-ray sources (ULXs) are unique in exhibiting moderately bright X-ray luminosities, LX ~ 1038-1040 ergs s-1, and relatively high blackbody temperatures, Tin ~ 1.0-2.0 keV. From the constraint that LX cannot exceed the Eddington luminosity LE, we require relatively high black hole masses, M ~ 10-100 M☉; however, for such large masses the standard disk theory predicts lower blackbody temperatures, Tin < 1.0 keV. To understand a cause of this puzzling fact, we carefully calculate the accretion flow structure shining at ~LE, fully taking into account the advective energy transport in the optically thick regime and the transonic nature of the flow. Our calculations show that at high accretion rate ( ≳ 30LE/c2) an apparently compact region with a size of Rin ≃ (1-3)rg (with rg being the Schwarzschild radius) is shining with a blackbody temperature of Tin ≃ 1.8(M/10 M☉)-1/4 keV even for the case of a nonrotating black hole. Furthermore, Rin decreases as increases, contrary to the canonical belief that the inner edge of the disk is fixed at the radius of the marginally stable last circular orbit. Accordingly, the loci of a constant black hole mass on the H-R diagram (representing the relation between LX and Tin both on the logarithmic scales) are not straight but bent toward the lower M-direction in the frame of the standard disk relation. We also plot the ASCA data of some ULXs on the same H-R diagram, finding that they all fall on the regions with relatively high masses, M ~ 10-30 M☉, and high accretion rates, ≳ 10LE/c2. Interestingly, IC 342 source 1, in particular, was observed to move along the constant M line (not constant Rin line) in our simulations. This provides firm evidence that at least some ULXs are shining at ≳LE and contain black holes with M ≃ 10-100 M☉.

Subfields: Astronomy and Astrophysics, Biomedical Engineering

View Paper: https://www.semanticscholar.org/paper/9743702f4c3da9e7ed19888a4f948f95ed6623ef

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In Astronomy and Astrophysics

1. Ramesh Narayan
2. A. Sa̧dowski
3. A. Tchekhovskoy
4. F. Yuan
5. J. McKinney
6. H. Feng
7. R. Soria
8. Yucong Zhu

In Biomedical Engineering

1. R. Soria
2. H. Feng
3. Ramesh Narayan
4. F. Yuan
5. A. Tchekhovskoy
6. A. Sa̧dowski
7. Yucong Zhu
8. T. Roberts

Citations in the corpus

• GLOBAL STRUCTURE OF THREE DISTINCT ACCRETION FLOWS AND OUTFLOWS AROUND BLACK HOLES FROM TWO-DIMENSIONAL RADIATION-MAGNETOHYDRODYNAMIC SIMULATIONS (2011, background): “…the past decade: subcritical accretion onto intermediate-mass black holes with the black hole mass greatly exceeding 100M⊙ (e.g., Makishima et al. 2000; Miller et al. 2004) and supercritical accretion onto stellar-mass black holes with mass of 3 − 20M⊙ (e.g., King et al. 2001; Watarai et al. 2001).”
• The Ultraluminous State (2009, background): “Standard (MCD) discs have p fixed at 0.75, but increasing amounts of advection can be modeled by decreasingp, with fully advective discs havingp ≃ 0.5 (e.g Watarai et al. 2001, Vierdayanti et al. 2006, Miyawaki et al.2006).”
• Hot Accretion Flows Around Black Holes (2014, methodology): “The slim disk model has been applied to narrow-line Seyfert galaxies (Mineshige et al. 2000), objects like SS433 (Fabrika 2004) and ultraluminous X-ray sources (Watarai et al. 2001).”
• The Ultraluminous X-Ray Source Population from the Chandra Archive of Galaxies (2004, background): “…necessary to attain an accretion rate, Ṁ>∼10−6b M⊙ yr−1, as the apparent luminosity scales as ∼6×1045Ṁ/b ergs s−1 [and so the slim-disk scenario that applies at high accretion rates (Abramowicz et al. 1988; Watarai et al. 2001; Ebisawa et al. 2003) may be favored over standard thin-disk models].”
• Ultraluminous X-ray sources in the Chandra and XMM-Newton era (2011, methodology): “…2009; Takeuchi et al. 2010; Mineshige & Ohsuga 2011) supported and advanced earlier analytical results (slim disk models; Abramowicz et al. 1988; Watarai et al. 2001; Ebisawa et al. 2003; Heinzeller & Duschl 2007), and the radiation-hydrodynamical simulations of, among others, Ohsuga et al.…”
• Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes (2012, background): “Super-Eddington accretion may also apply to ultraluminous X-ray sources (e.g. Watarai et al. 2001; Kawashima et al. 2012).”