Remnant radio galaxy candidates of small angular sizes
  Remnant radio galaxies (RRGs), characterized by the cessation of AGN
activity, represent a short-lived last phase of radio galaxy's life-cycle.
Hitherto, searches for RRGs, mainly based on the morphological criteria, have
identified large angular size sources resulting into a bias towards the
remnants of powerful FR-II radio galaxies. In this study we make the first
attempt to perform a systematic search for RRGs of small angular sizes
($<$30$^{\prime\prime}$) in the XMM-LSS field. By using spectral curvature
criterion we discover 48 remnant candidates exhibiting strong spectral
curvature ${\it i.e.}$; ${\alpha}_{\rm 150~MHz}^{\rm 325~MHz}$ - ${\alpha}_{\rm
325~MHz}^{\rm 1.4~GHz}$ $\geq$0.5. Spectral characteristics at higher frequency
regime ($>$1.4 GHz) indicate that some of our remnant candidates can depict
recurrent AGN activity with an active core. We place an upper limit on the
remnant fraction ($f_{\rm rem}$) to be 3.9$\%$, which increases to 5.4$\%$ if
flux cutoff limit of S$_{\rm 150~MHz}$ $\geq$10 mJy is considered. Our study
unveils, hitherto unexplored, a new population of small-size ($<$200 kpc)
remnant candidates that are often found to reside in less dense environments
and at higher redshifts ($z$) $>$1.0. We speculate that a relatively shorter
active phase and/or low jet power can be plausible reasons for the small size
of remnant candidates.
