Nimbus Roman is a serif typeface created by URW Studio in 1982.
Nimbus Roman No. 9 L is a serif typeface created by URW Studio in 1987, and eventually released under the GPL and AFPL (as Type 1 font for Ghostscript) in 1996 and LPPL in 2009. It features Normal, Bold, Italic, and Bold Italic weights, and is one of several freely licensed fonts offered by URW++.
Although the characters are not exactly the same, Nimbus Roman No. 9 L has metrics almost identical to Times New Roman and Times Roman. It is one of the Ghostscript fonts, a free alternative to 35 basic PostScript fonts (which include Times).
It is a standard typeface in many Linux distributions.