The complex intracluster medium of Abell 1569 and its interaction with
  central radio galaxies
  We present the first in-depth study of X-ray emission from a nearby
($z\sim0.0784$) galaxy cluster Abell 1569 using an archival $Chandra$
observation. A1569 consists of two unbound subclusters $-$ a northern
subcluster (A1569N) hosting a double-lobed radio galaxy 1233+169 at its centre,
and a southern subcluster (A1569S) harbouring a wide-angle-tailed (WAT) radio
source 1233+168. X-ray emission from A1569N and A1569S extends to a radius
$r\sim248$ kpc and $r\sim370$ kpc, respectively, indicating that the two gas
clumps are group-scale systems. The two subclusters have low X-ray luminosities
($\sim10^{42-43}$ erg s$^{-1}$), average elemental abundances $\sim$1/4
Z$_\odot$, low average temperatures ($\sim2$ keV), and lack large
($r\gtrsim40-50$ kpc) cool cores associated with the intracluster gas. We
detect a pair of cavities coincident with the radio lobes of 1233+169 in
A1569N. The total mechanical power associated with the cavity pair is an order
of magnitude larger than the X-ray radiative loss in the cavity-occupied
region, providing corroborating evidence for cavity-induced heating of the
intragroup gas in A1569N. A1569S exhibits possible evidence for a small-scale
cluster-subcluster merger, as indicated by its high central entropy, and the
presence of local gas elongation and a density discontinuity in between the
bent radio tails of 1233+168. The discontinuity is indicative of a weak merger
shock with Mach Number, $M\sim1.7$. The most plausible geometry for the ongoing
interaction is a head-on merger occurring between A1569S and a subcluster
falling in from the west along the line bisecting the WAT tails.
