We report optical observations of TGSS J1054+5832, a candidate high-redshift ($$z=4.8\pm 2$$z=4.8±2) steep-spectrum radio galaxy, in r and i bands, using the faint object spectrograph and camera mounted on 3.6-m Devasthal Optical Telescope (DOT). The source previously detected at 150 MHz from Giant Meterwave Radio Telescope (GMRT) and at 1420 MHz from Very Large Array has a known counterpart in near-infrared bands with K-band magnitude of AB 22. The source is detected in i-band with AB$$24.3\pm 0.2$$24.3±0.2 magnitude in the DOT images presented here. The source remains undetected in the r-band image at a 2.5$$\sigma $$σ depth of AB 24.4 mag over an $$1.2''\times 1.2''$$1.2′′×1.2′′ aperture. An upper limit to $$i-K$$i-K color is estimated to be $$\sim $$∼2.3, suggesting youthfulness of the galaxy with active star formation. These observations highlight the importance and potential of the 3.6-m DOT for detections of faint galaxies.

中文翻译：

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用 3.6 米 Devasthal 光学望远镜光学探测 GMRT 探测到的候选高红移射电星系

我们报告了 TGSS J1054+5832 的光学观测，它是一个候选的高红移 ($$z=4.8\pm 2$$z=4.8±2) 陡光谱射电星系，在 r 和 i 波段，使用微弱天体光谱仪和安装在 3.6 米 Devasthal 光学望远镜 (DOT) 上的相机。之前从巨型米波射电望远镜 (GMRT) 和 1420 MHz 频率从巨型米波射电望远镜 (GMRT) 和超大阵列在 1420 MHz 处检测到的源在 K 波段幅度为 AB 22 的近红外波段中具有已知对应物。此处显示的 DOT 图像中的 AB$$24.3\pm 0.2$$24.3±0.2 等。在 2.5$\sigma $$σ 深度的 AB 24.4 mag 和 $1.2''\times 1.2''$$1.2''×1.2'' 孔径的 r 波段图像中仍未检测到源。$$iK$$iK 颜色的上限估计为 $$\sim $$∼2.3，表明星系年轻，恒星形成活跃。