中国科学院云南天文台学术报告通知

2026年第27期

报告题目：Probing the corona in X-ray binaries: a spectral-timing perspective on state transitions

报告人：Dr. Federico García

报告人单位：Instituto Argentino de Radioastronomía (IAR, CONICET / UNLP / CICPBA)

报告语言：English

报告时间：2026年5月27日（星期三）10:00-12:00

报告地点：科研1号楼318会议室

报告摘要：

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X-ray binaries (XRBs) are systems where a compact object, either a black hole or a neutron star, accretes matter from a stellar companion. During transient outbursts, these systems undergo state transitions, evolving from thermal-dominated soft states to corona-dominated hard states where inverse Comptonization prevails. The hard and intermediate states, in particular, exhibit strong X-ray variability across a wide range of timescales, accompanied by narrow features known as quasi-periodic oscillations (QPOs).
To analyze these rapid dynamics, we employ spectral-timing Fourier techniques. By measuring variability amplitudes and phase lags across different energy bands, these methods allow us to constrain the geometry of the inner accretion flow and the mechanisms governing radiation propagation near the compact object. Crucially, these fast-timing properties provide physical constraints that cannot be decoupled from the stationary spectrum alone.

In this talk, I will review the spectral-timing phenomenology of XRBs and present the application of a time-dependent Comptonization model to these variable systems. Finally, I will discuss how modeling these rapid variations enables us to characterize the evolution of the corona during state transitions and outburst cycles.

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报告人简介：

Dr. Federico García is an Independent Staff Researcher from CONICET based at the Argentine Institute of Radioastronomy (IAR), where he has held a permanent position since 2021. He obtained his PhD from the National University of La Plata (UNLP) in 2016, and subsequently completed postdoctoral positions at IAR, the University of Paris Cité / CEA-Saclay in France, and the Kapteyn Astronomical Institute in the Netherlands. His primary research lies in high-energy astrophysics, specializing in accretion processes in X-ray binary systems containing black holes and neutron stars. Additionally, he conducts radio pulsar observations utilizing the radioastronomical antennas at IAR. Currently, he is visiting YNAO for one month as an ANSO Visiting Fellow from CAS.

云台邀请方：星系类星体研究团组

邀请方联系人：张国宝