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E-INSPIRE - I. Bridging the gap with the local Universe: Stellar population of a statistical sample of ultra-compact massive galaxies at z < 0.3

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2025)

Authors:

John Mills, Chiara Spiniello, Alexey Sergeyev, Crescenzo Tortora, Vladyslav Khramtsov, Giuseppe D’Ago, Michalina Maksymowicz-Maciata, João PV Benedetti, Anna Ferré-Mateu, Michele Cappellari, Roger Davies, Johanna Hartke, Charles Rosen

Abstract:

Abstract This paper presents the first effort to Extend the Investigation of Stellar Populations In RElics (E-INSPIRE). We present a catalogue of 430 spectroscopically-confirmed ultra-compact massive galaxies (UCMGs) from the Sloan Digital Sky Survey at redshifts 0.01 < z < 0.3. This increases the original INSPIRE sample eightfold, bridging the gap with the local Universe. For each object, we compute integrated stellar velocity dispersion, age, metallicity, and [Mg/Fe] through spectroscopic stellar population analysis. We infer star formation histories (SFHs), metallicity evolution histories (MEHs) and compute the Degree of Relicness (DoR) of each object. The UCMGs, covering a wide range of DoR from 0.05 to 0.88, can be divided into three groups, according to how extreme their SFH was. The first group consists of 81 extreme relics (DoR ≳ 0.6) that have formed the totality of their stellar mass by z ∼ 2 and have super-solar metallicities at all cosmic epochs. The second group (0.3 ≲ DoR ≲ 0.6) contains 293 objects also characterised by peaked SFHs but with a small percentage of later-formed stars and with a variety of MEHs. The third group (DoR ≲ 0.3), has 56 objects that cannot be considered relics since they have extended SFHs and formed a non-negligible fraction (>25 %) of their stellar mass at z < 2. We conclude that the most efficient method of finding relics is to select UCMGs with a combination of large velocity dispersion values (as already found by INSPIRE), super-solar metallicities and high [Mg/Fe].
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Contemporaneous optical-radio observations of a fast radio burst in a close galaxy pair

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 538:3 (2025) 1800-1815

Authors:

KY Hanmer, I Pastor-Marazuela, J Brink, D Malesani, BW Stappers, PJ Groot, AJ Cooper, N Tejos, DAH Buckley, ED Barr, MC Bezuidenhout, S Bloemen, M Caleb, LN Driessen, R Fender, F Jankowski, M Kramer, DLA Pieterse, KM Rajwade, J Tian, PM Vreeswijk, R Wijnands, PA Woudt
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Joint Radiative and Kinematic Modelling of X-ray Binary Ejecta: Energy Estimate and Reverse Shock Detection

ArXiv 2503.10804 (2025)

Authors:

AJ Cooper, JH Matthews, F Carotenuto, R Fender, GP Lamb, TD Russell, N Sarin, K Savard
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Looking at the Distant Universe with the MeerKAT Array: The H i Mass Function in the Local Universe

The Astrophysical Journal American Astronomical Society 981:2 (2025) 208

Authors:

Amir Kazemi-Moridani, Andrew J Baker, Marc Verheijen, Eric Gawiser, Sarah-Louise Blyth, Danail Obreschkow, Laurent Chemin, Jordan D Collier, Kyle W Cook, Jacinta Delhaize, Ed Elson, Bradley S Frank, Marcin Glowacki, Kelley M Hess, Benne W Holwerda, Zackary L Hutchens, Matt J Jarvis, Melanie Kaasinen, Sphesihle Makhathini, Abhisek Mohapatra, Hengxing Pan, Anja C Schröder, Leyya Stockenstroom, Mattia Vaccari, Tobias Westmeier, John F Wu, Martin Zwaan
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Type I X-ray Burst Emission Reflected into the Eclipses of EXO 0748−676

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2025) staf395

Authors:

Amy H Knight, Jakob van den Eijnden, Adam Ingram, James H Matthews, Sara E Motta, Matthew Middleton, Giulio C Mancuso, Douglas JK Buisson, Diego Altamirano, Rob Fender, Timothy P Roberts
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