HI absorption associated with Norma's brightest cluster galaxy

ESO 137-G006 is the brightest cluster galaxy (BCG) of the cool-core and dynamically young Norma cluster. We discover an atomic hydrogen (HI) absorption line associated with this BCG using the Australia Telescope Compact Array. We estimate a gas column density of $\approx (1.3 \pm 0.2) \times 10^{20}\,T_{\rm{spin}}$ atoms cm$^{-2}$ with spin temperature, $T_{\rm{spin}} \leq 194$ K, consistent with the HI properties of other early-type galaxies and cool-core cluster BCGs. The relationship between the presence of cold gas and a cluster cooling flow is unclear. Our results support the scenario that ESO 137-G006 may be a recent arrival to the cluster centre and not the original BCG. This scenario is consistent with the observed spatial alignment of the BCG's wide-angle tail radio lobes with Norma's X-ray sub-cluster and the significant line-of-sight velocity offset between the mean velocity of Norma and that of the BCG.Comment: Accepted for publication in MNRAS. 10 pages, 3 figures (additional 4 pages, 3 figures in appendix

Original research by young twinkle students (ORBYTS): Ephemeris refinement of transiting exoplanets

We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 min) in their transit times or have not been observed for over 3 yr. A fully robotic ground-based telescope network, observations from citizen astronomers, and data from TESS have been used to study eight planets, refining their ephemerides and orbital data. Such follow-up observations are key for ensuring accurate transit times for upcoming ground- and space-based telescopes, which may seek to characterize the atmospheres of these planets. We find deviations from the expected transit time for all planets, with transits occurring outside the 1σ uncertainties for seven planets. Using the newly acquired observations, we subsequently refine their periods and reduce the current predicted ephemeris uncertainties to 0.28-4.01 min. A significant portion of this work has been completed by students at two high schools in London as part of the Original Research By Young Twinkle Students (ORBYTS) programme.Fil: Edwards, Billy. Colegio Universitario de Londres; Reino UnidoFil: Changeat, Quentin. Colegio Universitario de Londres; Reino UnidoFil: Yip, Kai Hou. Colegio Universitario de Londres; Reino UnidoFil: Tsiaras, Angelos. Colegio Universitario de Londres; Reino UnidoFil: Taylor, Jake. University of Oxford; Reino UnidoFil: Akhtar, Bilal. Preston Manor High School; Reino UnidoFil: Aldaghir, Josef. Preston Manor High School; Reino UnidoFil: Bhattarai, Pranup. Preston Manor High School; Reino UnidoFil: Bhudia, Tushar. Beal High School; Reino UnidoFil: Chapagai, Aashish. Preston Manor High School; Reino UnidoFil: Huang, Michael. Preston Manor High School; Reino UnidoFil: Kabir, Danyaal. Beal High School; Reino UnidoFil: Khag, Vieran. Beal High School; Reino UnidoFil: Khaliq, Summyyah. Beal High School; Reino UnidoFil: Khatri, Kush. Preston Manor High School; Reino UnidoFil: Kneth, Jaidev. Beal High School; Reino UnidoFil: Kothari, Manisha. Beal High School; Reino UnidoFil: Najmudin, Ibrahim. Preston Manor High School; Reino UnidoFil: Panchalingam, Lobanaa. Beal High School; Reino UnidoFil: Patel, Manthan. Preston Manor High School; Reino UnidoFil: Premachandran, Luxshan. Beal High School; Reino UnidoFil: Qayyum, Adam. Beal High School; Reino UnidoFil: Rana, Prasen. Preston Manor High School; Reino UnidoFil: Shaikh, Zain. Preston Manor High School; Reino UnidoFil: Syed, Sheryar. Beal High School; Reino UnidoFil: Theti, Harnam. Beal High School; Reino UnidoFil: Zaidani, Mahmoud. Preston Manor High School; Reino UnidoFil: Saraf, Manasvee. Colegio Universitario de Londres; Reino UnidoFil: Di Sisto, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentin