The discovery of a multiphase cluster cool core lacking a brightest cluster galaxy

Abell 1142 is a nearby low mass cluster containing two comparable brightest cluster galaxies (BCGs). Previous Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), making it a cluster cool core lacking a BCG. The ongoing merger may have separated the cluster cool core from one of the BCGs. Our recent IRAM 30 meter observations have detected strong CO 1-0 emission from this X-ray peak, corresponding to a molecular mass of 2×10⁹ solar mass. The cold gas in this orphan cool core is likely formed from the long sought runaway cooling, precisely due to the absence of supermassive blackhole feedback, although a ram pressure origin of the cold gas remains viable.