This paper presents the multi-wavelength analysis of a 13 s quasi-periodic pulsation ( QPP ) observed in hard X-ray ( 12–300 keV ) and microwave ( 4.9–34 GHz ) emissions during a C-class flare occurred on 21 September 2015 .
AIA 304 and 171 Å images show an emerging loop/flux tube ( L1 ) moving radially outward , which interacts with preexisting structures within the active region .
The QPP was observed during the expansion and rising motion of L1 .
The Nobeyama Radioheliograph ( NoRH ) microwave images in 17/34 GHz channels reveal a single radio source , which was co-spatial with a neighboring loop ( L2 ) .
In addition , using AIA 304 Å images , we detected intensity oscillations in the legs of loop L2 with a period of about 26 s. A similar oscillation period was observed in the GOES soft X-ray flux derivative .
This oscillation period seems to increase with time .
We suggest that the observed QPP is most likely generated by the interaction between loops L2 and L3 observed in the AIA hot channels ( 131 and 94 Å ) .
The merging speed of loops L2 and L3 was \sim 35 km s ^ { -1 } .
Loop L1 destroyed possibly by its interaction with preexisting structures in the active region and produced a cool jet with the speed \sim 106–118 km s ^ { -1 } associated with a narrow CME ( \sim 770 km s ^ { -1 } ) .
Another mechanism of the QPP in terms of a sausage oscillation of the loop ( L2 ) is also possible .