The X-ray luminosity-temperature relation of a complete sample of low-mass galaxy clusters

TL;DR

This study analyzes the X-ray luminosity-temperature relation in low-mass galaxy clusters, finding it consistent with that of more massive clusters, with some variation in relaxed systems, providing a robust benchmark for feedback models.

Contribution

It presents the first complete, bias-corrected analysis of the L-T relation in low-mass galaxy clusters, extending understanding to lower mass regimes.

Findings

The L-T relation slope is consistent with that of massive clusters.

No significant difference in normalization or scatter between low-mass and massive clusters.

Relaxed systems show a steeper core-excised L-T relation slope.

Abstract

We present \Chandra\ observations of 23 galaxy groups and low-mass galaxy clusters at $0.03<z<0.15$ with a median temperature of ~2keV. The sample is a statistically complete flux-limited subset of the 400 deg$^2$ survey. We investigated the scaling relation between X-ray luminosity ($L$) and temperature ($T$), taking selection biases fully into account. The logarithmic slope of the bolometric \LT\ relation was found to be $3.29\pm0.33$, consistent with values typically found for samples of more massive clusters. In combination with other recent studies of the \LT\ relation we show that there is no evidence for the slope, normalisation, or scatter of the \LT\ relation of galaxy groups being different than that of massive clusters. The exception to this is that in the special case of the most relaxed systems, the slope of the core-excised \LT\ relation appears to steepen from the self-similar value found for massive clusters to a steeper slope for the lower mass sample studied here. Thanks to our rigorous treatment of selection biases, these measurements provide a robust reference against which to compare predictions of models of the impact of feedback on the X-ray properties of galaxy groups.