What is the Secret Behind the X-Ray Variability in the Symbiotic Binary GX 1+4?
Faculty Mentor Name
Pragati Pradhan
Format Preference
Poster
Abstract
This project aims to advance the understanding of matter in extreme environments by analyzing the first broadband monitoring of the symbiotic X-ray binary GX 1+4 conducted almost every month in 2024–2025 using near-simultaneous data from the NICER and NuSTAR X-ray telescopes. The primary scientific objective is to investigate competing theories proposed in the literature for the X-ray emission from GX 1+4 caused by (i) inverse Compton scattering in an accretion column (similar to many high-mass X-ray binaries where the neutron star is endowed with a strong magnetic field), with or without a wind-fed accretion disk; and (ii) Compton reflection off a cold, optically thick structure, likely the inner region of an accretion disk or torus.
We will also discuss the possibility of X-ray variability in GX 1+4 caused by quasi-spherical accretion. The pulse profiles display a wide range of morphologies, including double- and triple-peaked structures, which are observed to vary with both energy and luminosity. In this work, we investigate the energy and luminosity dependence of the profiles, with a particular focus on understanding the origin and evolution of the dips unveiled across different pulse phases. This study provides new insights into the accretion geometry and emission mechanisms in GX 1+4
What is the Secret Behind the X-Ray Variability in the Symbiotic Binary GX 1+4?
This project aims to advance the understanding of matter in extreme environments by analyzing the first broadband monitoring of the symbiotic X-ray binary GX 1+4 conducted almost every month in 2024–2025 using near-simultaneous data from the NICER and NuSTAR X-ray telescopes. The primary scientific objective is to investigate competing theories proposed in the literature for the X-ray emission from GX 1+4 caused by (i) inverse Compton scattering in an accretion column (similar to many high-mass X-ray binaries where the neutron star is endowed with a strong magnetic field), with or without a wind-fed accretion disk; and (ii) Compton reflection off a cold, optically thick structure, likely the inner region of an accretion disk or torus.
We will also discuss the possibility of X-ray variability in GX 1+4 caused by quasi-spherical accretion. The pulse profiles display a wide range of morphologies, including double- and triple-peaked structures, which are observed to vary with both energy and luminosity. In this work, we investigate the energy and luminosity dependence of the profiles, with a particular focus on understanding the origin and evolution of the dips unveiled across different pulse phases. This study provides new insights into the accretion geometry and emission mechanisms in GX 1+4