Study of Wide-Field-of-View X-ray Observations of the Virgo Cluster Using the Lobster Eye Imager for Astronomy

TL;DR

This paper demonstrates LEIA's capability to image and analyze the Virgo Cluster in X-ray, validating its effectiveness for extended source imaging and spectral measurements in space astronomy.

Contribution

The study presents the first validation of LEIA's imaging and spectral resolution capabilities for extended X-ray sources like galaxy clusters.

Findings

LEIA successfully imaged the Virgo Cluster in the 0.5-4.5 keV band.

The measured cluster temperature is consistent with previous X-ray observations.

The spectrum above 1.6 keV is dominated by background X-ray noise.

Abstract

The Lobster Eye Imager for Astronomy (LEIA) is the pathfinder of the wide-field X-ray telescope used in the Einstein Probe mission. In this study, we present an image of the Virgo Cluster taken by LEIA in the 0.5-4.5 keV band with an exposure time of $\sim$17.3 ks in the central region. This extended emission is generally consistent with the results obtained by ROSAT. However, the field is affected by bright point sources due to the instrument's Point Spread Function (PSF) effect. Through fitting of the LEIA spectrum of the Virgo Cluster, we obtained a temperature of $2.1^{+0.3}_{-0.1}$ keV, which is consistent with the XMM-Newton results ($\sim$2.3 keV). Above 1.6 keV, the spectrum is dominated by the X-ray background. In summary, this study validates LEIA's extended source imaging and spectral resolution capabilities for the first time.