| Summary: | 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<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>″</mo></mrow></msup></semantics></math></inline-formula>) in the XMM–LSS field. By using spectral curvature criterion we discover 48 remnant candidates exhibiting strong spectral curvature i.e., <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi>α</mi><mrow><mn>150</mn><mspace width="3.33333pt"></mspace><mi>MHz</mi></mrow><mrow><mn>325</mn><mspace width="3.33333pt"></mspace><mi>MHz</mi></mrow></msubsup><mo>−</mo><msubsup><mi>α</mi><mrow><mn>325</mn><mspace width="3.33333pt"></mspace><mi>MHz</mi></mrow><mrow><mn>1.4</mn><mspace width="3.33333pt"></mspace><mi>GHz</mi></mrow></msubsup></mrow></semantics></math></inline-formula> ≥ 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 (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>f</mi><mi>rem</mi></msub></semantics></math></inline-formula>) to be 3.9%, which increases to 5.4% if flux cutoff limit of S<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>150</mn><mspace width="3.33333pt"></mspace><mi>MHz</mi></mrow></msub></semantics></math></inline-formula> ≥ 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 (<i>z</i>) > 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.
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