Once you are satisfied with the filters applied to your prospecting list, head to Step 2- "View and Sort Results"- to inspect the companies which have matched your criteria.
"Hotness" in the context of Prospector indicates which companies have been active in the news recently. This can be used to identify actively trading, interesting or "hot" prospects to follow.
The "Hotness-Selected News" option allows you to view companies which have been in the news recently by specific topics, such as winning awards or acquiring new business. Clicking on the "Hotness-Selected News" button will open up a list of topics for you to choose from- tick those you are interested in, then click the "Apply" button to sort the results of your search based on their topics.
Once applied, news for these companies will specifically reflect your selected "Hotness" topics. These can then be changed again at any time by simply following the above steps again.