The peculiar disk evolution of 4U 1630--472 observed by Insight-HXMT during the 2022 and 2023 outbursts

Abstract

We study the spectral properties of the black hole X-ray transient binary 4U 1630--472 during the 2022 and 2023 outbursts with Insight-HXMT observations. We find that the outbursts are in peculiar soft states. The effect of the hardening factor on the disk temperature is taken into account by kerrbb, and the flux and temperature of the disk are found to follow $F\propto T_{\mathrm{eff}}^{3.92\pm 0.13}$ and $F\propto T_{\mathrm{eff}}^{4.91\pm 1.00}$, for the two outbursts respectively. The flux-temperature relation is roughly consistent with holding a standard disk, By fitting with the p-free model, the p-value is found to have anti-correlation with disk temperature. Combined a joint diagnostic in a diagram of the relation between the non-thermal fraction and luminosity, by enclosing as well the previous outbursts, reveals a possible pattern for the disk evolution toward a slim one, and such an evolution may depend on the fraction of the non-thermal emission in the high soft state.

14 pages, 14 pages,3 tables. Published in ApJ

References in corpus (12)

• Black hole mass determination in the X-ray binary 4U 1630--47: Scaling of spectral and variability characteristics
• The Insight-HXMT mission and its recent progresses
• Accretion and ejection in black-hole X-ray transients
• X-ray Polarization of the Black Hole X-ray Binary 4U 1630-47 Challenges Standard Thin Accretion Disk Scenario
• Insight-HXMT observations of 4U~1636-536: Corona cooling revealed with single short type-I X-ray burst
• A Delayed Transition to the Hard State for 4U 1630-47 at the End of Its 2010 Outburst
• The spins of the Galactic black holes in MAXI J1535-571 and 4U 1630-472 from Insight-HXMT
• Insight-HXMT Study of the Inner Accretion Disk in the Black Hole Candidate EXO 1846--031
• The peculiar spectral evolution of the new X-ray transient MAXI J0637-430
• Spectropolarimetric study of 4U 1630$-$47 in Steep Power law state with IXPE and NICER
• Back to business: SLX 1746--331 after 13 years of silence
• NICER, NuSTAR and Insight-HXMT views to black hole X-ray binary SLX 1746--331