«A Microquasar Odyssey: Unveiling the Complexities»

Understanding the Enigmatic Nature of the Transient X-ray Binary 4U 1630–47

Not scheduled

15m

Palazzo Municipale - Sala delle Capriate (Cefalù (Palermo))

Talk Talk Accretion-ejection (observation, theory, simulations)

Speaker

Fiamma Capitanio (Istituto Nazionale di Astrofisica (INAF))

Description

4U 1630-47 is a peculiar transient X-ray binary believed to host a black hole as its compact object. Its behavior differs from that of other BH-XRBs, as it shows recurrent outbursts with a fairly regular recurrence period and lacks bright hard states. In contrast, its soft-state spectra above 10 keV are characterized by a strong power-law component extending up to 200 keV without any cutoff.
A large multiwavelength campaign was carried out during the 2022/2023 outburst, involving NICER, NuSTAR, INTEGRAL, and IXPE observations.
In particular, IXPE revealed a higher level of polarization than typically observed in other X-ray binaries which is difficult to explain as the result of scattering, even for a high-inclination system or a highly asymmetric corona.
Here, I will review the main characteristics of this enigmatic source and discuss possible explanations for its peculiar behavior in light of the new spectro-polarimetric results.