Search for IR Emission from Intracluster Dust in A2029

TL;DR

This study searched for infrared emission from intracluster dust in galaxy cluster A2029, setting upper limits that align with theoretical expectations and indicating detection challenges due to cirrus noise.

Contribution

First to set observational upper limits on IR emission from intracluster dust in A2029, highlighting detection difficulties with current IR telescope sensitivity.

Findings

Detected weak signals consistent with cirrus fluctuations.

Established upper limits on IR emission from intracluster dust.

Results support dust deficiency in the cluster compared to the Milky Way.

Abstract

We have searched for IR emission from the intracluster dust (ICD) in the galaxy cluster A2029. Weak signals of enhanced extended emission in the cluster are detected at both 24 and 70 micron. However, the signals are indistinguishable from the foreground fluctuations. The 24 versus 70 micron color map does not discriminate the dust emission in the cluster from the cirrus emission. After excluding the contamination from the point sources, we obtain upper limits for the extended ICD emission in A2029, 5 x 10^3 Jy/sr at 24 micron and 5 x 10^4 Jy/sr at 70 micron. The upper limits are generally consistent with the expectation from theoretical calculations and support a dust deficiency in the cluster compared to the ISM in our galaxy. Our results suggest that even with the much improved sensitivity of current IR telescopes, a clear detection of the IR emission from ICD may be difficult due to cirrus noise.