Publications (56)
Capturing Goodwillie's Derivative
David Barnes, Rosona Eldred
Recent work of Biedermann and Röndigs has translated Goodwillie's calculus of functors into the language of model categories. Their work focuses on symmetric multilinear functors…
Classifying rational G-spectra for profinite G
David Barnes, Danny Sugrue
For G an arbitrary profinite group, we construct an algebraic model for rational G-spectra in terms of G-equivariant sheaves over the space of subgroups of G. This generalises the…
Where are the High Velocity Clouds in Local Group Analogs?
D. J. Pisano, David Barnes, Brad Gibson +3
High-velocity clouds (HVCs) are clouds of HI seen around the Milky Way with velocities inconsistent with Galactic rotation, have unknown distances and masses and controversial orig…
Profinite equivariant spectra and their tensor-triangular geometry
Scott Balchin, David Barnes, Tobias Barthel
We study the tensor-triangular geometry of the category of equivariant -spectra for a profinite group, . Our starting point is the construction of a ``continu…
CCCP and MENeaCS: (updated) weak-lensing masses for 100 galaxy clusters
Ricardo Herbonnet, Cristóbal Sifón, Henk Hoekstra +7
Large area surveys have detected significant samples of galaxy clusters that can be used to constrain cosmological parameters, provided that the masses of the clusters are measured…
An analysis of interplanetary solar radio emissions associated with a coronal mass ejection
Vratislav Krupar, Jonathan Eastwood, Oksana Kruparova +12
Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma that may cause severe geomagnetic storms if Earth-directed. Here we report a rare instance with compreh…
Homological Localisation of Model Categories
David Barnes, Constanze Roitzheim
One of the most useful methods for studying the stable homotopy category is localising at some spectrum E. For an arbitrary stable model category we introduce a candidate for the E…
Comparing the orthogonal and homotopy functor calculi
David Barnes, Rosona Eldred
Goodwillie's homotopy functor calculus constructs a Taylor tower of approximations to F, often a functor from spaces to spaces. Weiss's orthogonal calculus provides a Taylor tower…
Deconstructing span categories for profinite groups
David Barnes, Niall Taggart
One of the major advantages of -category theory over classical -category theory is its robust and homotopically meaningful framework for taking (co)limits of diagrams of…
Predicting CME Arrivals with Heliospheric Imagers from L5: A Data Assimilation Approach
Tanja Amerstorfer, Justin Le Louëdec, David Barnes +5
The Solar TErrestrial RElations Observatory (STEREO) mission has laid a foundation for advancing real-time space weather forecasting by enabling the evaluation of heliospheric imag…
Solar Transient Recognition Using Deep Learning (STRUDL) for heliospheric imager data
Maike Bauer, Justin Le Louëdec, Tanja Amerstorfer +3
Coronal Mass Ejections (CMEs) are space weather phenomena capable of causing significant disruptions to both space- and ground-based infrastructure. The timely and accurate detecti…
Setting the scene for BUFFALO: A study of the matter distribution in the HFF galaxy cluster MACS J0416.1-2403 and its parallel field
Elizabeth J. Gonzalez, MartÃn Chalela, Mathilde Jauzac +11
In the context of the BUFFALO (Beyond Ultra-deep Frontier Fields And Legacy Observations) survey, we present a new analysis of the merging galaxy cluster MACS\,J0416.1-2403 ($z = 0…
Rational Equivariant Spectra
David Barnes
We develop model categories of rational equivariant spectra whose homotopy categories are equivalent to the category of rational equivariant cohomology theories. We prove that give…
The equivalence between rational G-sheaves and rational G-Mackey functors for profinite G
David Barnes, Danny Sugrue
For G a profinite group, we construct an equivalence between rational G-Mackey functors and a certain full subcategory of G-sheaves over the space of closed subgroups of G called W…
Properties of the ionized CGM and IGM: a comparison of galaxy formation models via the Sunyaev-Zel'dovich effect
S. H. Lim, David Barnes, Mark Vogelsberger +5
We present a comparison of the physical properties of the ionized gas in the circumgalactic (CGM) and intergalactic (IGM) media at between observations and four cosmologic…
An algebraic model for rational toral G-spectra
David Barnes, J. P. C. Greenlees, Magdalena Kedziorek
For G a compact Lie group, toral G-spectra are those rational G-spectra whose geometric isotropy consists of subgroups of a maximal torus of G. The homotopy category of rational to…
What do loose groups tell us about galaxy formation?
D. J. Pisano, David Barnes, Brad Gibson +3
We present the results of a Parkes Multibeam HI survey of six loose groups of galaxies analogous to the Local Group. This survey was sensitive to HI-rich objects in these groups to…
An algebraic model for rational naive-commutative equivariant ring spectra
David Barnes, J. P. C. Greenlees, Magdalena Kedziorek
Equipping a non-equivariant topological E_\infty operad with the trivial G-action gives an operad in G-spaces. The algebra structure encoded by this operad in G-spectra is characte…
Prospects for Redshifted 21-cm observations of quasar HII regions
Stuart Wyithe, Abraham Loeb, David Barnes
The introduction of low-frequency radio arrays over the coming decade is expected to revolutionize the study of the reionization epoch. Observation of the contrast in redshifted 21…
Rational Z_p-Equivariant Spectra
David Barnes
We find a simple algebraic model for rational G-equivariant spectra, where G is the p-adic integers, via a series of Quillen equivalences. This model, along with an Adams short exa…
Rational Equivariant Rigidity
David Barnes, Constanze Roitzheim
We prove that if G is the circle group or a profinite group, then the all of the homotopical information of the category of rational G-spectra is captured by triangulated structure…
L1 and off Sun-Earth line visible-light imaging of Earth-directed CMEs: An analysis of inconsistent observations
Richard A. Harrison, Jackie A. Davies, David Barnes +1
The efficacy of coronal mass ejection (CME) observations as a key input to space weather forecasting is explored by comparing on and off Sun-Earth line observations from the ESA/NA…
Constraining the inner density slope of massive galaxy clusters
Qiuhan He, Hongyu Li, Ran Li +7
We determine the inner density profiles of massive galaxy clusters (M > M) in the Cluster-EAGLE (C-EAGLE) hydrodynamic simulations, and investi…
Classifying Dihedral O(2)-Equivariant Spectra
David Barnes
The category of rational O(2)-equivariant spectra splits as a product of cyclic and dihedral parts. Using the classification of rational G-equivariant spectra for finite groups G,…
Rational O(2)-Equivariant Spectra
David Barnes
The category of rational O(2)-equivariant cohomology theories has an algebraic model A(O(2)), as established by work of Greenlees. That is, there is an equivalence of categories be…
CME Magnetic Structure and IMF Preconditioning Affecting SEP Transport
Erika Palmerio, Emilia K. J. Kilpua, Olivier Witasse +15
Coronal mass ejections (CMEs) and solar energetic particles (SEPs) are two phenomena that can cause severe space weather effects throughout the heliosphere. The evolution of CMEs,…
An algebraic model for rational excisive functors
David Barnes, Magdalena KÄdziorek, Niall Taggart
We provide a new proof of the rational splitting of excisive endofunctors of spectra as a product of their homogeneous layers independent of rational Tate vanishing. We utilise the…
Splitting rational incomplete Mackey functors
David Barnes, Michael A. Hill, Magdalena Kedziorek
Inspired by equivariant homotopy theory, equivariant algebra studies generalisations of G-Mackey functors that do not have all transfer maps (also known as induction maps), for G a…
Fast Holographic Deconvolution: a new technique for precision radio interferometry
Ian Sullivan, Miguel Morales, Bryna Hazelton +48
We introduce the Fast Holographic Deconvolution method for analyzing interferometric radio data. Our new method is an extension of A-projection/software-holography/forward modeling…
Universal logic with encoded spin qubits in silicon
Aaron J. Weinstein, Matthew D. Reed, Aaron M. Jones +20
Qubits encoded in a decoherence-free subsystem and realized in exchange-coupled silicon quantum dots are promising candidates for fault-tolerant quantum computing. Benefits of this…
The signal of decaying dark matter with hydrodynamical simulations
Mark R. Lovell, David Barnes, Yannick Bahé +11
Dark matter particles may decay, emitting photons. Drawing on the EAGLE family of hydrodynamic simulations of galaxy formation -- including the APOSTLE and C-EAGLE simulations -- w…
Model Categories for Orthogonal Calculus
David Barnes, Peter Oman
We restate the notion of orthogonal calculus in terms of model categories. This provides a cleaner set of results and makes the role of O(n)-equivariance clearer. Thus we develop m…
An Algorithm for Optimal Partitioning of Data on an Interval
Brad Jackson, Jeffrey D. Scargle, David Barnes +7
Many signal processing problems can be solved by maximizing the fitness of a segmented model over all possible partitions of the data interval. This letter describes a simple but p…
Stable left and right Bousfield localisations
David Barnes, Constanze Roitzheim
We study left and right Bousfield localisations of stable model categories which preserve stability. This follows the lead of the two key examples: localisations of spectra with re…
Local Framings
David Barnes, Constanze Roitzheim
Framings provide a way to construct Quillen functors from simplicial sets to any given model category. A more structured set-up studies stable frames giving Quillen functors from s…
Early-type galaxy density profiles from IllustrisTNG: II. Evolutionary trend of the total density profile
Yunchong Wang, Mark Vogelsberger, Dandan Xu +8
We study the evolutionary trend of the total density profile of early-type galaxies (ETGs) in IllustrisTNG. To this end, we trace ETGs from to and measure the power-law…
Simulating the dark matter decay signal from the Perseus galaxy cluster
Mark R. Lovell, Dmytro Iakubovskyi, David Barnes +4
The nearby Perseus galaxy cluster is a key target for indirect detection searches for decaying dark matter. We use the C-EAGLE simulations of galaxy clusters to predict the flux, w…
Rational Orthogonal Calculus
David Barnes
We show that one can use model categories to construct rational orthogonal calculus. That is, given a continuous functor from vector spaces to based spaces one can construct a towe…
First Spectroscopic Imaging Observations of the Sun at Low Radio Frequencies with the Murchison Widefield Array Prototype
Divya Oberoi, Lynn D. Matthews, Iver H. Cairns +67
We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array (MWA), observed on 2010 March 27. Our observations span the…
Splitting Monoidal Stable Model Categories
David Barnes
If C is a stable model category with a monoidal product then the set of homotopy classes of self-maps of the unit S forms a commutative ring. An idempotent e of this ring will spli…
Polarimetric Tomography Applied to Synthetic Multi-Spacecraft White-Light Images: Observing Coronal Mass Ejections in 3D
David Barnes, Erika Palmerio, Tanja Amerstorfer +7
A discrete tomography method has been developed that is able to reconstruct three-dimensional coronal mass ejection (CME) density structure. We test the method by producing synthet…
The connection between mass, environment and slow rotation in simulated galaxies
Claudia del P. Lagos, Joop Schaye, Yannick Bahe +5
Recent observations from integral field spectroscopy (IFS) indicate that the fraction of galaxies that are slow rotators, , depends primarily on stellar mass, with no s…
Classifying Rational G-Spectra for Finite G
David Barnes
We give a new proof that for a finite group G, the category of rational G-equivariant spectra is Quillen equivalent to the product of the model categories of chain complexes of mod…
Global dimension of the category of rational incomplete Mackey functors for a finite abelian group G
David Barnes, Anna Marie Bohmann, Michael A. Hill +1
In this paper, we analyse the global dimension of the category of rational incomplete Mackey functors over a finite abelian group. Incomplete Mackey functors have recently risen to…
Magnetic Structure and Propagation of Two Interacting CMEs from the Sun to Saturn
Erika Palmerio, Teresa Nieves-Chinchilla, Emilia K. J. Kilpua +14
One of the grand challenges in heliophysics is the characterisation of coronal mass ejection (CME) magnetic structure and evolution from eruption at the Sun through heliospheric pr…
A monoidal algebraic model for rational SO(2)-spectra
David Barnes
The category of rational SO(2)-equivariant spectra admits an algebraic model. That is, there is an abelian category A(SO(2)) whose derived category is equivalent to the homotopy ca…
Equivariant sheaves for profinite groups
David Barnes, Danny Sugrue
We study equivariant sheaves over profinite spaces, where the group is also taken to be profinite. We resolve a serious deficit in the existing theory by constructing a good notion…
Is there enough star formation in simulated protoclusters?
Seunghwan Lim, Douglas Scott, Arif Babul +5
As progenitors of the most massive objects, protoclusters are key to tracing the evolution and star-formation history of the Universe, and are responsible for per c…
Early-type galaxy density profiles from IllustrisTNG: I. Galaxy correlations and the impact of baryons
Yunchong Wang, Mark Vogelsberger, Dandan Xu +10
We explore the isothermal total density profiles of early-type galaxies (ETGs) in the IllustrisTNG simulation. For the selected 559 ETGs at with stellar mass $10^{10.7}\mat…
An algebraic model for rational naive-commutative ring SO(2)-spectra and equivariant elliptic cohomology
David Barnes, J. P. C. Greenlees, Magdalena Kedziorek
Equipping a non-equivariant topological -operad with the trivial -action gives an operad in -spaces. For a -spectrum, being an algebra over this operad does not…
An introduction to algebraic models for rational G-spectra
David Barnes, Magdalena Kedziorek
The project of Greenlees et al. on understanding rational G-spectra in terms of algebraic categories has had many successes, classifying rational G-spectra for finite groups, SO(2)…
Monoidality of Franke's Exotic Model
David Barnes, Constanze Roitzheim
We discuss the monoidal structure on Franke's algebraic model for the -local stable homotopy category at odd primes and show that its Picard group is isomorphic to the int…
A Dwyer-Rezk classification for polynomial functors in Weiss calculus
David Barnes, Magdalena KÄdziorek, Niall Taggart
In Goodwillie calculus, unpublished work of Dwyer and Rezk provides a classification of reduced filtered colimit preserving -excisive functors from pointed spaces to spectra as…
Multipoint study of successive coronal mass ejections driving moderate disturbances at 1 AU
Erika Palmerio, Camilla Scolini, David Barnes +10
We analyse in this work the propagation and geoeffectiveness of four successive coronal mass ejections (CMEs) that erupted from the Sun during 21--23 May 2013 and that were detecte…
REBAR: Reference Ethical Benchmark for Autonomy Readiness
Jonathan Diller, David Barnes, Rebekah Bogdanoff +14
As autonomous systems grow more advanced, objective metrics to evaluate their ethical and legal compliance are critical for informing end users of their limitations and ensuring ac…
-operads and associahedra
Scott Balchin, David Barnes, Constanze Roitzheim
We provide a new combinatorial approach to studying the collection of N-infinity-operads in G-equivariant homotopy theory for G a finite cyclic group. In particular, we show that f…