We present results based on the systematic analysis of Chandra archive data on the X-ray bright Abell Richness class-I type cluster Abell 1991 with an objective to investigate properties of the X-ray cavities hosted by this system .
The unsharp masked image as well as 2-d \beta model subtracted residual image of Abell 1991 reveals a pair of X-ray cavities and a region of excess emission in the central \sim 12 kpc region .
Both the cavities are of ellipsoidal shape and exhibit an order of magnitude deficiency in the X-ray surface brightness compared to that in the undisturbed regions .
Spectral analysis of X-ray photons extracted from the cavities lead to the temperature values equal to 1.77 _ { -0.12 } ^ { +0.19 } keV for N-cavity and 1.53 _ { -0.06 } ^ { +0.05 } keV for S-cavity , while that for the excess X-ray emission region is found to be equal to 2.06 _ { -0.07 } ^ { +0.12 } keV .
Radial temperature profile derived for Abell 1991 reveals a positive temperature gradient , reaching to a maximum of 2.63 keV at \sim 76 kpc and then declines in outward direction .
0.5 - 2.0 keV soft band image of the central 15″region of Abell 1991 reveals relatively cooler three different knot like features that are about 10″off the X-ray peak of the cluster .
Total power of the cavities is found to be equal to \sim 8.64 \times 10 ^ { 43 } erg s ^ { -1 } , while the X-ray luminosity within the cooling radius is found to be 6.04 \times 10 ^ { 43 } erg s ^ { -1 } , comparison of which imply that the mechanical energy released by the central AGN outburst is sufficient to balance the radative loss .