Imaging-spectroscopy diagnosis of the giant sloshing spiral in the Virgo cluster with the Einstein Probe Follow-up X-ray Telescope

TL;DR

This study uses deep X-ray observations from the Einstein Probe Follow-up X-ray Telescope to reveal a giant spiral structure in the Virgo cluster, supporting a gas sloshing origin due to a minor merger.

Contribution

First detailed imaging of the Virgo cluster's giant sloshing spiral using EP-FXT, confirming previous findings and providing new temperature, metallicity, and entropy maps.

Findings

Identified a coherent spiral structure connecting cold fronts.

Temperature and metallicity maps support gas sloshing scenario.

EP-FXT measurements agree with XMM-Newton data.

Abstract

We performed deep X-ray observations of the Virgo cluster using the Einstein Probe Follow-up X-ray Telescope (EP-FXT) with a total exposure of 295 ks. Leveraging the large field of view (FoV) and low particle background of EP-FXT, the image reveals a giant spiral feature connecting the cold fronts in the northwest and southeast, forming a coherent structure consistent with earlier results from XMM-Newton and Suzaku. We also present two-dimensional maps of temperature, metallicity, and entropy across the Virgo Cluster, covering a FoV of approximately 28.5 arcmin. These maps clearly show a spiral structure with high density, low temperature, high metallicity, and low entropy. The results support a scenario where the spiral morphology arises from gas sloshing driven by a minor merger. Additionally, EP-FXT temperature measurements agree well with XMM-Newton data within uncertainties.