EP-FXT Observations of Abell 1795: X-ray Properties and Structure out to $R_{200}$

Abstract

We present deep X-ray observations of the nearby, X-ray luminous galaxy cluster Abell 1795 obtained with the Einstein Probe Follow-up X-ray Telescope (EP-FXT), with a total exposure time of 480 ks. Exploiting the large field of view and low particle background of EP-FXT, we directly measure the radial temperature profile of A1795 out to $R_{200}$ with full azimuthal coverage, which increases with radius within 6 arcmin and then gradually declines toward larger radii. The surface-brightness residual map and 2D thermodynamic maps reveal a clockwise spiral structure extending from the cluster core toward the southeast, which traces low-temperature, low-entropy gas and is consistent with sloshing-induced cold fronts. In the northwest, the surface-brightness-enhanced region exhibits an arc-like high-temperature feature, and both the temperature-derived and density-derived Mach numbers support that it is a weak shock. These substructures can be explained by a binary merger scenario: the perturbing subcluster induces sloshing during its first passage past the primary core, and its subsequent return passage through the ICM may drive the shock toward the northwest. Our results indicate that relaxed galaxy clusters such as A1795 can still retain signatures of dynamical activity.