Probing the cosmological 21 cm global signal from the Antarctic ice sheet 后印本

摘要: The  redshifted  21  cm  line,  arising  from  neutral  hydrogen,  offers  a  unique  probe  into  the  intergalactic medium  and  the  first  stars  and  galaxies  formed  in  the  early  universe.  However,  detecting  this  signal is a challenging task  because  of  artificial  radio-frequency  interference  (RFI)  and  systematic  errors  such  as  ground  effects.  The  interior of  the  Antarctic  continent  provides  an  excellent  location  to  make  such observations,  with  minimal  RFI  and  relatively stable  foreground  signals.  Moreover,  a  flat  plateau  in  central  Antarctica,  with  an  ice  cap  over 2000 m  deep,  will  show less ground reflection of radio waves, reducing the signal complexity in the area around the probing antenna. It may be advantageous  to  perform  cosmological  21  cm  experiments  in  Antarctica,  and  a  21  cm Antarctic global  spectrum experiment  can  potentially  be  deployed  on  the  Antarctic  ice  cap.  We  have  performed  preliminary  instrumental  design, system  calibration,  and  implementation  of  such  an  instrument  optimized for  extreme  cold  and  capable  of  long-term autonomous  operation.  This  system  shows  the  ability  to  effectively  detect  the  21  cm  signal,  confirming  Antarctica  as an excellent observational site for radio cosmology.