Morse code is well known. Can you decrypt this? Download the file here. Wrap your answer with picoCTF{}, put underscores in place of pauses, and use all lowercase.
Use a website like this morse code decoder. Upload the file. The output was WH47 H47H 90D W20U9H7. We replace the spaces with underscores to get the flag.
picoCTF{WH47_H47H_90D_W20U9H7}