An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

An old galaxy with faint emission lines whose ratios are similar to those of → LINERs, i.e. galaxies with low-ionization nuclear emission-line regions. All galaxies after consuming their → molecular clouds, where stars are formed, follow a "passive" evolution during which their → stellar populations simply get older and older. The old stellar populations contain hot post-→ AGB stars and → white dwarfs which are able to ionize the surrounding gas and produce spectra identical to those of LINERS.

Retired in the sense "withdrawn from or no longer occupied with one's business or profession," p.p. of retire, from M.Fr. retirer "to withdraw (something)," from → re- "back" + O.Fr. tirer "to draw;" → galaxy. The concept of retired galaxies was first proposed by G. Stasińska et al. (2008, MNRAS 391, L29) to name the final stages of galaxies that cease their star forming activity. The word "retired" is also to be taken by opposition to "active" in the sense of "containing an accreting black hole" (like Seyfert galaxies), since liners are often thought to be a scaled down version of Seyfert nuclei.

Bâznešasté "retired," literally "seated back, seated away," from bâz-→ re- + nešasté "seated," p.p. of nešastan "to sit;" Mid.Pers. nišastan "to sit;" O.Pers. nišādayam [1 sg.impf.caus.act.] "to sit down, to establish," hadiš- "abode;" Av. nišasiiā [1 sg.subj.acr.] "I shall sit down," from nihad- "to sit down," from ni- "down, in, into," → ni-, + had- "to sit;" PIE base *sed- "to sit;" cf. Skt. sad- "to sit," sidati "sits;" Gk. hezomai "to sit," hedra "seat, chair;" L. sedere "to sit;" O.Ir. suide "seat, sitting;" Welsh sedd "seat;" Lith. sedmi "to sit;" Rus. sad "garden;" Goth. sitan, Ger. sitzen; E. sit.

Exhausted of strength and energy.

Past participle of tire "to weary; become weary," M.E. tyren, O.E. teorian, of unknown origin.

Xasté "tired; hurt, wounded;" Mid.Pers. xastan, xad- "to injure, wound;" Av. vīxaδ- "to crush;" Proto-Iranian *xad- "to wound, hurt."

The hypothesis that photons from distant objects lose energy during their intergalactic journey to us, thereby increasing in wavelength and becoming redshifted. This would provide an alternative to the → Big Bang model in accounting for the → redshifts of distant galaxies. However, there is no evidence for any such tired-light effect. First discussed by F. Zwicky (1929, Proceedings of the National Academy of Sciences, 15, 773).

→ tired; → light.