The HEASARC is running nominally. If you are trying to download a lot of data, please consider using the AWS cloud copy of most HEASARC data. As an alternative to locally installing HEASoft, SciServer is an online platform which has the software installed and data available when you login.
set xybinsize
Sets the rebinning factor for the image. The boolean parameter rebinregion determines whether xselect will attempt to adjust any region files to the new binning. ds9 region files in sky coordinates do not need to be rebinned but saoimage or saotng files do.