Galaxy formation and evolution: publications

The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2

Astronomy & Astrophysics EDP Sciences 695 (2025) a80

Authors:

TW Shimwell, CL Hale, PN Best, A Botteon, A Drabent, MJ Hardcastle, V Jelić, JMGHJ de Jong, R Kondapally, HJA Röttgering, C Tasse, RJ van Weeren, WL Williams, A Bonafede, M Bondi, M Brüggen, G Brunetti, JR Callingham, F De Gasperin, KJ Duncan, C Horellou, S Iyer, I de Ruiter, K Małek, DG Nair, LK Morabito, I Prandoni, A Rowlinson, J Sabater, A Shulevski, DJB Smith, F Sweijen

The environments of radio galaxies and quasars in LoTSS data release 2

Astronomy & Astrophysics EDP Sciences 695 (2025) A69-A69

Authors:

T Pan, Y Fu, HJA Rottgering, RJ van Weeren, AB Drake, BH Yue, JW Petley

Abstract:

Aims. The orientation-based unification scheme of radio-loud active galactic nuclei (AGNs) asserts that radio galaxies and quasars are essentially the same type of object, but viewed from different angles. To test this unification model, we compared the environments of radio galaxies and quasars, which would reveal similar properties when an accurate model is utilized. Methods. Using the second data release of the LOFAR Two-metre Sky Survey (LoTSS DR2), we constructed a sample of 26 577 radio galaxies and 2028 quasars at 0.08 < z < 0.4. For radio galaxies with optical spectra, we further classified them as 3631 low-excitation radio galaxies (LERGs) and 1143 high-excitation radio galaxies (HERGs). We crossmatched these samples with two galaxy cluster catalogs from the Sloan Digital Sky Survey (SDSS). Results. We find that 17.1 ± 0.2% of the radio galaxies and 4.1 ± 0.4% of the quasars are associated with galaxy clusters. Luminous quasars are very rare in clusters, while 18.7 ± 0.7% LERGs and 15.2 ± 1.1% HERGs reside in clusters. We also note that in radio galaxies, both HERGs and LERGs tend to reside in the centers of clusters, while quasars do not show a strong preference for their positions in clusters. Conclusions. This study shows that local quasars and radio galaxies exist in different environments, challenging the orientation-based unification model. This means that factors other than orientation may play an important role in distinguishing radio galaxies from quasars. The future WEAVE-LOFAR survey will offer high-quality spectroscopic data for a large number of radio sources and allow for a more comprehensive exploration of the environments of radio galaxies and quasars.

The jet paths of radio active galactic nuclei and their cluster weather

Astronomy & Astrophysics EDP Sciences 695 (2025) a178

Authors:

E Vardoulaki, V Backöfer, A Finoguenov, F Vazza, J Comparat, G Gozaliasl, IH Whittam, CL Hale, JR Weaver, AM Koekemoer, JD Collier, B Frank, I Heywood, S Sekhar, AR Taylor, S Pinjarkar, MJ Hardcastle, T Shimwell, M Hoeft, SV White, F An, F Tabatabaei, Z Randriamanakoto, MD Filipovic

Constraints on the active galactic nucleus and starburst activity of local ultraluminous infrared galaxies from a broad range of torus models

Monthly Notices of the Royal Astronomical Society 91̽�� University Press (OUP) 538:1 (2025) 426-453

Authors:

Charalambia Varnava, Andreas Efstathiou, Duncan Farrah, Dimitra Rigopoulou

Detection of the 2175Å UV Bump at z>7: Evidence for Rapid Dust Evolution in a Merging Reionisation-Era Galaxy

(2025)

Authors:

Katherine Ormerod, Joris Witstok, Renske Smit, Anna de Graaff, Jakob M Helton, Michael V Maseda, Irene Shivaei, Andrew J Bunker, Stefano Carniani, Francesco D'Eugenio, Rachana Bhatawdekar, Jacopo Chevallard, Marijn Franx, Nimisha Kumari, Roberto Maiolino, Pierluigi Rinaldi, Brant Robertson, Sandro Tacchella

91̽��