Hintze Centre for Astrophysical Surveys: publications

Bye-bye, Local-in-matter-density Bias: The Statistics of the Halo Field Are Poorly Determined by the Local Mass Density

The Astrophysical Journal Letters American Astronomical Society 977:2 (2024) ARTN L44

Authors:

Deaglan J Bartlett, Matthew Ho, Benjamin D Wandelt

Abstract:

Abstract Bias models relating the dark matter field to the spatial distribution of halos are widely used in current cosmological analyses. Many models predict halos purely from the local Eulerian matter density, yet bias models in perturbation theory require other local properties. We assess the validity of assuming that only the local dark matter density can be used to predict the number density of halos in a model-independent way and in the nonperturbative regime. Utilizing N-body simulations, we study the properties of the halo counts field after spatial voxels with near-equal dark matter density have been permuted. If local-in-matter-density (LIMD) biasing were valid, the statistical properties of the permuted and unpermuted fields would be indistinguishable since both represent equally fair draws of the stochastic biasing model. If the Lagrangian radius is greater than approximately half the voxel size and for halos less massive than ∼1015 h −1 M ☉, we find the permuted halo field has a scale-dependent bias with greater than 25% more power on scales relevant for current surveys. These bias models remove small-scale power by not modeling correlations between neighboring voxels, which substantially boosts large-scale power to conserve the field’s total variance. This conclusion is robust to the choice of initial conditions and cosmology. Assuming LIMD halo biasing cannot, therefore, reproduce the distribution of halos across a large range of scales and halo masses, no matter how complex the model. One must either allow the biasing to be a function of other quantities and/or remove the assumption that neighboring voxels are statistically independent.

Identification of the optical counterpart of the fast X-ray transient EP240414a

(2024)

Authors:

S Srivastav, T-W Chen, JH Gillanders, L Rhodes, SJ Smartt, ME Huber, A Aryan, S Yang, A Beri, AJ Cooper, M Nicholl, KW Smith, HF Stevance, F Carotenuto, KC Chambers, A Aamer, CR Angus, MD Fulton, T Moore, IA Smith, DR Young, T de Boer, H Gao, C-C Lin, T Lowe, EA Magnier, P Minguez, Y-C Pan, RJ Wainscoat

Radio Galaxies in SIMBA: A MIGHTEE Comparison

ArXiv 2412.09824 (2024)

Authors:

Nicole L Thomas, Imogen H Whittam, Catherine L Hale, Leah K Morabito, Romeel Davé, Matt J Jarvis, Robin HW Cook

Evaluating cosmological biases using photometric redshifts for Type Ia Supernova cosmology with the Dark Energy Survey Supernova Program

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) (2024) stae2703

Authors:

RC Chen, D Scolnic, M Vincenzi, ES Rykoff, J Myles, R Kessler, B Popovic, M Sako, M Smith, P Armstrong, D Brout, TM Davis, L Galbany, J Lee, C Lidman, A Möller, BO Sánchez, M Sullivan, H Qu, P Wiseman, TMC Abbott, M Aguena, S Allam, O Alves, F Andrade-Oliveira, J Annis, D Bacon, D Brooks, A Carnero Rosell, J Carretero, A Choi, C Conselice, LN da Costa, MES Pereira, HT Diehl, P Doel, S Everett, I Ferrero, B Flaugher, J Frieman, J García-Bellido, M Gatti, E Gaztanaga, G Giannini, D Gruen, RA Gruendl, G Gutierrez, K Herner, SR Hinton, DL Hollowood, K Honscheid, D Huterer, DJ James, K Kuehn, GF Lewis, M Lima, JL Marshall, J Mena-Fernández, F Menanteau, R Miquel, RLC Ogando, A Palmese, A Pieres, AA Plazas Malagón, A Roodman, S Samuroff, E Sanchez, D Sanchez Cid, I Sevilla-Noarbe, E Suchyta, MEC Swanson, G Tarle, C To, DL Tucker, V Vikram, N Weaverdyck, J Weller

Galaxy formation and symbiotic evolution with the inter-galactic medium in the age of ELT-ANDES

Experimental Astronomy Springer 58:3 (2024) 21

Authors:

Valentina D’Odorico, James S Bolton, Lise Christensen, Annalisa De Cia, Erik Zackrisson, Aron Kordt, Luca Izzo, Jiangtao Li, Roberto Maiolino, Alessandro Marconi, Philipp Richter, Andrea Saccardi, Stefania Salvadori, Irene Vanni, Chiara Feruglio, Michele Fumagalli, Johan PU Fynbo, Pasquier Noterdaeme, Polychronis Papaderos, Céline Péroux, Aprajita Verma, Paolo Di Marcantonio, Livia Origlia, Alessio Zanutta

Abstract:

High-resolution absorption spectroscopy toward bright background sources has had a paramount role in understanding early galaxy formation, the evolution of the intergalactic medium and the reionisation of the Universe. However, these studies are now approaching the boundaries of what can be achieved at ground-based 8-10m class telescopes. The identification of primeval systems at the highest redshifts, within the reionisation epoch and even into the dark ages, and of the products of the first generation of stars and the chemical enrichment of the early Universe, requires observing very faint targets with a signal-to-noise ratio high enough to detect very weak spectral signatures. In this paper, we describe the giant leap forward that will be enabled by ANDES, the high-resolution spectrograph for the ELT, in these key science fields, together with a brief, non-exhaustive overview of other extragalactic research topics that will be pursued by this instrument, and its synergistic use with other facilities that will become available in the early 2030s.

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