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Physics Astrophysics Cosmology and Nongalactic Astrophysics

astro-ph.CO Watch Cosmology and Nongalactic Astrophysics

Thursday 3 September

Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.IM

ALPACA I: Controlling source and PSF systematics in JWST time-delay cosmography with differentiable lens modeling

Hrvoje Krizic, Martin Millon, Aymeric Galan et al. (+2 more)

Time-delay cosmography provides an independent probe of the Hubble constant ($H_0$), but exploiting the high-resolution imaging of the James Webb Space Telescope (JWST) requires strong-lens models that capture complex source-galaxy morphologies and the point spread function (PSF) with high fidelity. Flexible source and joint PSF reconstruction are computationally expensive, motivating more rigid parameterizations that can bias the inferred time-delay distance $D_{\Delta t}$. We present ALPACA, a semi-automatic, GPU-accelerated, differentiable strong-lens modeling pipeline built on Herculens, Starred, and JAX. ALPACA jointly reconstructs a pixelated correlated-field source, the lens mass, and the PSF within a single likelihood, reducing per-system runtimes from weeks to less than 15 hours. We validate the pipeline on realistic mock JWST/NIRCam observations built from morphologically complex COSMOS galaxy sources. Holding an imperfect PSF (RMSE = 12% from truth) fixed biases $D_{\Delta t}$ by up to 14%, whereas joint PSF reconstruction reduces this bias to the percent level. We further show that the reconstructed PSF core can be marginalized over jointly with the lens parameters during posterior sampling. Propagating the per-lens posteriors of a ten-lens mock sample through hierarchical inference, we recover the input cosmology without significant bias. ALPACA shows that rigorous control of source and PSF systematics is computationally affordable, supporting reliable percent-level precision in the JWST era.
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All authors Hrvoje Krizic, Martin Millon, Aymeric Galan, Sydney Erickson, Phil Marshall

Cosmology and Nongalactic Astrophysics

Supernova microlensing as a probe of ultracompact minihalos and primordial cosmology

Djuna Croon, Sergio Sevillano Muñoz and Miguel Zumalacarregui

We propose using supernova microlensing to search for ultracompact minihalos and other extended dark structures seeded by enhanced primordial small-scale power. Unlike conventional microlensing searches, which are often optimized for primordial black holes, cosmological supernovae are sensitive to lenses with physical sizes comparable to their Einstein radii (up to $\sim {\rm pc}\left(M/10^4M_\odot\right)^{1/2}$ scale), opening a qualitatively different region of dark object parameter space. We compute the extended object detection efficiency relative to point lenses. We then show how projected limits on the abundance of ultracompact minihalos can be mapped, in benchmark formation scenarios, onto constraints on the primordial power spectrum. With the Vera C. Rubin Observatory expected to deliver an unprecedented LSST supernova sample, supernova microlensing is poised to become a timely and complementary probe of small-scale structure and the physics of the early Universe.
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Cosmology and Nongalactic Astrophysics

Euclid preparation. The shape of halo profiles in $\Lambda$CDM and non-standard cosmologies

Euclid Collaboration: L. Pizzuti, G. Y. Ferron, A. Ragagnin et al. (+303 more)

We study the shape of three-dimensional and projected dark-matter halo profiles extracted from cosmological $N$-body simulations in $\Lambda$CDM and non-standard cosmologies, using the DUSTGRAIN-PF and DEMNUni suites. The models considered include massive neutrinos, $f(\mathcal{R})$ gravity, and dynamical dark energy. By comparing density, mass, velocity-dispersion, and excess-surface-density profiles up to $5\,r_{500{\rm c}}$, we quantify the differential imprint of non-standard physics on halo structure in view of Euclid cluster WL studies. Our main analysis is performed at $z=1.1$, a high-redshift regime where the weak-lensing signal-to-noise starts to degrade, providing a conservative stress test for detectability; for DUSTGRAIN-PF we additionally analyse $z=0.5$ and $z=0.3$ snapshots. In low-mass haloes ($M_{\rm 200c}<7\times10^{13}\,M_\odot$), $f(\mathcal{R})$ gravity produces deviations of order $10\,\%$ in projected and three-dimensional profiles, especially in the outskirts where screening is less efficient. Massive neutrinos partially reduce this signal, reflecting the competition between free streaming and fifth-force-enhanced growth. Dynamical dark energy and massive-neutrino cosmologies generally induce smaller, few-percent deviations, with the largest effects again found in low-mass haloes and at large radii. Under simplified assumptions for \Euclid WL, detecting such profile differences at $z=1.1$ requires stacks of $\sim10^5$ haloes, while a few thousands haloes may be sufficient at $z\lesssim0.5$. This further calls for the need of integrating such precise modelling of non-standard effects – along with other observational effects – in any likelihood involving Euclid WL masses to avoid non-negligible systematic biases. Concentration–mass relations show weaker cosmology dependence, typically at the $\sim5\,\%$ level. [...]
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All authors Euclid Collaboration: L. Pizzuti, G. Y. Ferron, A. Ragagnin, A. M. C. Le Brun, P.-S. Corasaniti, T. Gayoux, G. Rácz, E. Altamura, Z. Sakr, C. Carbone, M. Baldi, C. Giocoli, T. Castro, F. Pace, J. E. Taylor, S. Borgani, O. Luongo, C. T. Mpetha, R. E. Angulo, B. Altieri, S. Andreon, N. Auricchio, C. Baccigalupi, S. Bardelli, P. Battaglia, A. Biviano, E. Branchini, M. Brescia, S. Camera, V. Capobianco, V. F. Cardone, J. Carretero, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, H. Degaudenzi, G. De Lucia, H. Dole, F. Dubath, X. Dupac, S. Dusini, S. Escoffier, M. Farina, F. Faustini, S. Ferriol, F. Finelli, P. Fosalba, S. Fotopoulou, M. Frailis, E. Franceschi, M. Fumana, L. Gabarra, S. Galeotta, K. George, B. Gillis, J. Gracia-Carpio, A. Grazian, F. Grupp, S. V. H. Haugan, S. Hemmati, W. Holmes, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, B. Joachimi, S. Kermiche, A. Kiessling, B. Kubik, K. Kuijken, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, M. Magliocchetti, G. Mainetti, O. Mansutti, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, N. Mauri, S. Maurogordato, E. Medinaceli, S. Mei, M. Meneghetti, E. Merlin, G. Meylan, P. Monaco, A. Mora, M. Moresco, C. Moretti, L. Moscardini, E. Munari, C. Neissner, J. W. Nightingale, C. Padilla, S. Paltani, F. Pasian, V. Pettorino, A. Pezzotta, S. Pires, G. Polenta, M. Poncet, L. A. Popa, F. Raison, A. Renzi, J. Rhodes, G. Riccio, I. Risso, E. Romelli, M. Roncarelli, R. Saglia, D. Sapone, B. Sartoris, P. Schneider, T. Schrabback, A. Secroun, E. Sefusatti, E. Sihvola, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J.-L. Starck, P. Tallada-Crespí, A. N. Taylor, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, E. A. Valentijn, J. Valiviita, T. Vassallo, Y. Wang, J. Weller, A. Zacchei, G. Zamorani, F. M. Zerbi, E. Zucca, M. Ballardini, P. Bergamini, A. Boucaud, E. Bozzo, C. Burigana, R. Cabanac, M. Calabrese, A. Cappi, F. Caro, J. A. Escartin Vigo, J. García-Bellido, T. Gasparetto, J. Macias-Perez, R. Maoli, R. B. Metcalf, M. Pöntinen, E. Sarpa, V. Scottez, M. Sereno, M. Tenti, M. Tucci, M. Viel, M. Wiesmann, J. A. Acevedo Barroso, Y. Akrami, I. T. Andika, S. Anselmi, M. Archidiacono, G. Aricò, F. Atrio-Barandela, M. Baes, L. Bazzanini, D. Bertacca, M. Bethermin, F. Beutler, A. Blanchard, L. Blot, H. Böhringer, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, C. S. Carvalho, F. Cogato, T. E. Collett, S. Conseil, A. R. Cooray, P. Corcho-Caballero, M. Costanzi, B. Csizi, O. Cucciati, T. de Boer, F. De Paolis, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, J. M. Diego, V. Duret, Y. Fang, A. Farina, A. Finoguenov, F. Fontanot, A. Franco, Y. Fu, K. Ganga, R. Gavazzi, E. Gaztanaga, Z. Ghaffari, F. Giacomini, F. Gianotti, E. J. Gonzalez, G. Gozaliasl, A. Gruppuso, M. Guidi, C. M. Gutierrez, A. Hall, N. A. Hatch, C. Hernández-Monteagudo, H. Hildebrandt, J. Hjorth, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, J. Kim, C. C. Kirkpatrick, A. Kovács, I. Kovačić, K. Koyama, S. Kruk, M. C. Lam, M. Lattanzi, L. Legrand, M. Lembo, G. Leroy, G. F. Lesci, J. Lesgourgues, L. Linke, A. Manjón-García, F. Mannucci, F. R. Marleau, C. J. A. P. Martins, M. Migliaccio, M. Miluzio, G. Morgante, S. Nadathur, K. Naidoo, A. Navarro-Alsina, S. Nesseris, F. Oppizzi, D. Paoletti, F. Passalacqua, K. Paterson, L. Patrizii, C. Pattison, R. Paviot, A. Pisani, D. Potter, G. W. Pratt, S. Quai, M. Radovich, G. Rodighiero, W. Roster, S. Sacquegna, M. Sahlén, D. B. Sanders, A. Schneider, D. Sciotti, E. Sellentin, S. Serjeant, F. Shankar, L. C. Smith, J. G. Sorce, I. Szapudi, K. Tanidis, C. Tao, F. Tarsitano, G. Testera, R. Teyssier, S. Tosi, A. Troja, C. Uhlemann, C. Valieri, A. Venhola, D. Vergani, G. Verza, P. Vielzeuf, S. Vinciguerra, M. von Wietersheim-Kramsta, L. Wang, A. H. Wright, H. W. Yeung

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Confronting the Higgsino Interpretation of the LZ Event with the High-Energy Sideband

Nicholas L. Rodd, Benjamin R. Safdi, Tracy R. Slatyer et al. (+1 more)

The LZ experiment has reported a single 248 keV nuclear recoil event in their $2.84$ ton-yr exposure on a xenon target. The absence of lower nuclear recoil events is naturally explained by inelastically scattering dark matter (DM), for which the nuclear recoil energy spectra are shifted upwards from zero. Excitingly, the observed rate and spectra are consistent with a thermal $1.1$ TeV higgsino that explains all of DM with a mass splitting $\delta \sim 370 - 490$ keV between the two lowest-lying Majorana states, with the range depending on the underlying DM velocity distribution. In this work, however, we show that higgsino DM with these properties would generically produce more higher-energy recoil events in a high-energy sideband along the LZ $S1c$ energy axis, while the LZ experiment reports no events in that bin. This suggests a possible tension which could be further explored by the LZ Collaboration, as the acceptance in that bin is not public. We further show that a non-thermal $\sim$500 GeV higgsino may evade the sideband constraint and that future experiments using heavy targets can potentially test the higgsino interpretation of the event either way.
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All authors Nicholas L. Rodd, Benjamin R. Safdi, Tracy R. Slatyer, Weishuang Linda Xu

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Inelastic Signatures of Electroweak Dark Matter

Juri Smirnov, Spencer Griffith and John F. Beacom

Minimal dark matter extended to include a Majorana and a Dirac multiplet coupled through the Higgs — the HC-MDM model — provides a compelling and predictive framework. We show that in certain limits of this model, the mass splitting and the inelastic interaction are representation-independent, while the thermal-relic masses are representation-dependent. We then show that this model can account for the high-energy recoil event recently reported by LUX-ZEPLIN (LZ) while also respecting thermal-relic, elastic-scattering, and solar-capture constraints. Generic inelastic DM models do not connect all these tests and generic Higgsino models do not survive them.
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Cosmology and Nongalactic Astrophysics

The moving lens effect: analytical modelling and foreground suppression

Amy Wayland, David Alonso and William Coulton

The moving lens (ML) effect is a secondary anisotropy of the cosmic microwave background (CMB) generated by the transverse motion of gravitational potentials, providing a direct probe of the large-scale cosmic velocity field. Its detection relies on cross-correlating a CMB map with the transverse galaxy momentum field, constructed from the galaxy overdensity and a velocity field reconstructed from it. Restricting the reconstruction to large-scale modes strongly suppresses contamination from small-scale astrophysical foregrounds while preserving the ML signal. In this work, we develop a theoretical framework for the ML estimator and its foreground contamination. We show that the signal and foregrounds have a distinct dependence on the direction of the long-wavelength mode represented by the reconstructed galaxy velocity. In the squeezed limit enforced by the velocity reconstruction filter, the bispectrum sourcing the foreground correlation becomes independent of this direction, causing its leading contribution to vanish after angular averaging. In turn, the ML signal survives by matching this directional dependence, with its amplitude reduced only by the filtered velocity variance. Using the halo model, we derive the leading corrections beyond the squeezed limit and show that the residual contamination remains parametrically suppressed. Finally, we model the cross-correlation exactly in the curved sky, and show that it is sourced solely by the longitudinal component of the galaxy momentum field, in the form of a spin-1 $E$-mode, with all other contributions either strongly suppressed on small scales or exactly zero.
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Cosmology and Nongalactic Astrophysics

Consistency between cosmological and standard siren observations in evolving dark energy

Macarena Lagos and William J. Wolf

A scalar field non-minimally coupled to gravity can be the driver of cosmic acceleration. Such a non-minimal coupling (NMC) can produce a non-zero gravitational-wave (GW) friction function $\alpha_M(z)$, which modifies the luminosity distance inferred from GW sources relative to its electromagnetic counterpart. We use a particular NMC scalar-tensor model, that explains time-varying dark energy in good alignment with DESI, to predict $\alpha_M(z)$ and the expected GW/EM luminosity-distance ratio $D_L^{\rm GW}/D_L^{\rm EM}$, and map it onto two common parametrizations—the $c_M$ and the $(\Xi_0,n)$ models. We find $c_M = -0.5\pm 0.2$ and $\Xi_0 = 0.88\pm 0.05$, $n=3.2\pm 0.3$, both consistent with GWTC-5 constraints at the $\lesssim 1\sigma$ level. This consistency is mostly driven by current large uncertainties in GW data, which lead to measurements consistent with both $\Lambda$CDM and the NMC model. By contrast, the dark energy constraints derived from analyzing cosmological data, under the common parametric scalar-tensor model using $\alpha_M(z)=c_M\Omega_\Lambda(z)/\Omega_{\Lambda 0}$ and the CPL parametrized equation of state $w_0w_a$, are in $2.2\sigma$ ($3.6\sigma$) tension with the NMC predictions for the $c_M$ ($w_0w_a$) parameter. We confirm that, in order to avoid cosmological instabilities, this parametrized model imposes strong implicit priors that are incompatible with physically-motivated scalar-tensor models when dark energy is dynamical.
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Cosmology and Nongalactic Astrophysics

Prospects for probing dark matter with filamentary 21cm emission

Yizhou Liu, Yingjie Jing, Haoran Shi et al. (+1 more)

The cosmic web contains most of the matter in the Universe, and its filamentary structure is closely related to the properties of dark matter. Compared with the cold dark matter (CDM) model, warm dark matter (WDM) suppresses the formation of low-mass halos and produces smoother cosmic filaments. In this work, we explore whether filamentary 21cm emission can be used to distinguish between these two dark matter models at $z=4$ and $2.5$. We generate intrinsic 21cm brightness temperature maps from cosmological hydrodynamical simulations and produce mock observations by convolving them with Gaussian beams of different angular resolutions. We then compare the predicted filament signals with the expected sensitivities of SKA1-Low and SKA2-Low. We find that the intrinsic 21cm emission clearly reflects the different filament morphologies in the CDM and WDM models, particularly at $z=4$. However, these differences rapidly disappear as the beam size increases, especially for beam sizes larger than 6 arcsec. Although larger beams improve the observational sensitivity, they also erase the small-scale structures that encode the dark matter information. As a result, neither SKA1-Low nor the planned SKA2-Low can directly resolve individual filaments with sufficient sensitivity to distinguish between the two models. We therefore conclude that direct imaging of cosmic filaments and constraining dark matter through their morphology are unlikely to be feasible with current and planned SKA-Low facilities.
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All authors Yizhou Liu, Yingjie Jing, Haoran Shi, Huijie Hu

Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.GA

Bright star-forming galaxies naturally forming at z>10 in the Shark semi-analytic model

Claudia D.P. Lagos, Angel Chandro-Gomez, Chris Power et al. (+1 more)

The James Webb Space Telescope (JWST) has unveiled the existence of numerous z>10 bright ultraviolet (UV) galaxies, potentially challenging galaxy formation models in a Lambda Cold Dark Matter (LCDM) universe. Modifications to star formation and stellar feedback models have been suggested to alleviate the tension. However, the fundamental challenge is to design a galaxy formation model that simultaneously reproduces observations from z=0 to those at the highest redshifts. Here, we present predictions from the Shark semi-analytic model of galaxy formation, which is tuned to reproduce the z=0 universe. We show that the same model is capable of reproducing the current UV luminosity function constraints even up to z=17 without the need to invoke variations in the baryon physics model. This model is also capable of reproducing reasonably well the stellar mass function evolution from z=0 to z=10 and the cosmic star formation rate (SFR) density at 0<z<15, again with the same baryon physics and parameters. The key to the success of Shark is the triggering of starbursts by violent disk instabilities included in the model, which leads to an increase in the variance of the UV luminosity with increasing halo mass at z>10. We demonstrate that without this mechanism, galaxies are not bursty enough in the model to reproduce the observations at z>10.
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All authors Claudia D.P. Lagos, Angel Chandro-Gomez, Chris Power, Aaron S.G. Robotham

Wednesday 2 September

Cosmology and Nongalactic Astrophysics

TDCOSMO XXIX: JWST/NIRSpec IFU Spatially Resolved Kinematics of Three Time-delay Lenses

Shawn Knabel, Pritom Mozumdar, Anowar J. Shajib et al. (+8 more)

Spatially resolved stellar kinematics are critical to the high precision achieved by cosmological probes utilizing time delays of strongly lensed quasars. Combined with high-resolution imaging and lens modeling, dynamical models of the 2D resolved kinematics of the deflector galaxy tightly constrain the mass profile and break the mass-sheet degeneracy, in turn providing tight constraints on the Hubble constant when the time delays are included. We extract stellar kinematics of the deflector galaxies in the quadruply lensed quasar systems HE0435-1223, PG1115+080, and WFI2033-4723 from James Webb Space Telescope Near-Infrared Spectrograph (JWST-NIRSpec) integral field spectroscopy. The kinematic maps reach average per-bin total (statistical and systematic) uncertainties of 6-11%, with average bin-to-bin correlated errors of only $\sim 1.2\%$. The aperture-integrated velocity dispersions are statistically consistent with the values used in the previous TDCOSMO analysis (all within $0.9\sigma$), with their average uncertainty reduced from 3.7% to 2.4% owing to improvements in the data reduction and kinematic-extraction methodology. We classify PG1115+080 as a fast rotator, HE0435-1223 and WFI2033-4723 as slow rotators within the probed radii, and we refine the source redshifts from the kinematics of the lensed host galaxies. Kinematic maps will be combined with time delays, lens models, and line-of-sight convergence estimates to measure cosmological parameters in the upcoming TDCOSMO 2026 milestone publication.
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All authors Shawn Knabel, Pritom Mozumdar, Anowar J. Shajib, Tommaso Treu, Devon M. Williams, Michele Cappellari, David Law, Simon Birrer, Takahiro Morishita, William Sheu, Massimo Stiavelli

Cosmology and Nongalactic Astrophysics

Reassessing Evidence for Dark-Sector Interactions with Dynamical Dark Energy and DESI DR2

Jincheng Wang, Hongwei Yu and Puxun Wu

Recent baryon acoustic oscillation measurements from DESI Data Release 2, when combined with CMB and supernova data, strengthen the motivation for exploring departures from $\Lambda$CDM in the late-time expansion history. Because an evolving dark-energy equation of state and an interaction within the dark sector can produce partially degenerate effects on the background expansion, their observational signatures should be assessed simultaneously. We first consider an interacting $w_0w_a$CDM model with $Q=\beta H\rho_{\rm de}$, using Planck and ACT CMB data, DESI DR2, and DES-Dovekie supernovae. Allowing the dark-energy equation of state to evolve substantially weakens the preference for a nonzero coupling, while the preference for dynamical dark energy persists. The interaction provides essentially no additional improvement in the best fit, suggesting that part of the coupling preference found in more restricted interacting models may reflect a degeneracy with dark-energy dynamics. We then examine the same interaction for three one-parameter dynamical dark-energy trajectories: thawing, mirage, and generalized emergent dark energy (GEDE). The role of the interaction depends strongly on the assumed trajectory. The thawing and GEDE models favor sizable couplings of opposite signs, whereas the mirage trajectory already closely follows the dark-energy evolution preferred by the data and provides little support for an additional interaction. These models also predict markedly different signatures in structure growth, ranging from enhanced matter clustering in the interacting thawing model to strong suppression in interacting GEDE. These contrasting growth signatures, despite substantial degeneracies at the background level, highlight late-time large-scale-structure observations as a promising avenue for distinguishing dark-energy dynamics from dark-sector interactions.
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Cosmology and Nongalactic Astrophysics

Beyond isolated curvature peaks: collective collapse and multiple Primordial Black Hole formation

Albert Escrivà

Primordial black hole (PBH) calculations usually treat rare curvature peaks as isolated collapsing regions. Using fully nonlinear $3+1$ numerical-relativity simulations in a radiation-dominated Universe, we demonstrate that neighbouring primordial curvature perturbations need not map one-to-one onto PBHs: they may ultimately disperse, collapse collectively into a single PBH, or undergo distinct local collapses and form more than one PBH. In the family of two-component profiles studied here, the latter outcome is a pair of PBHs, identified by the coexistence of two disconnected apparent horizons on at least one time slice. We introduce a nonspherical quasi-local compaction diagnostic based on the Hawking mass and referenced to a round flat-FLRW sphere of equal area. It retains the angular structure of the curvature field and reduces to the standard Misner-Sharp compaction function in spherical symmetry. The global maximum of this diagnostic, $\mathcal K_{\rm form}$, provides an empirical indicator of whether at least one PBH forms, with a transition near $\mathcal K_{\rm form,c}\approx0.56$ and modest profile-dependent scatter. For forming bimodal profiles, we supplement the nonlinear compactness with a signed linear surface strength evaluated on the same probing spheres. The viability of the weaker local branch and the competition between the local and common-enclosing branches improve the empirical discrimination between single- and double-PBH outcomes. Our results therefore show that the maximum curvature amplitude alone does not determine the collapse outcome, which also depends on the spatial extent, characteristic scales, and geometry of the surrounding curvature environment.
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Cosmology and Nongalactic Astrophysics

Universal CMB Phase Coherence from Single-Field Inflation

Siméon Vareilles, Thomas Colas, Julien Grain et al. (+2 more)

The phase coherence of primordial perturbations shapes the acoustic peaks of the CMB and is regarded as a key signature of inflation. Inflationary scenarios at different energy scales, thus with different durations, are commonly expected to leave different levels of coherence. We show this expectation fails: because the curvature perturbation is conserved on super-Hubble scales, the coherence at recombination inherits a value fixed by the observed primordial spectrum alone. This holds irrespective of the inflationary energy scale and the subsequent expansion history.
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All authors Siméon Vareilles, Thomas Colas, Julien Grain, Federico Piazza, Vincent Vennin

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th

Gravitational Backreaction in de Sitter: A Canonical ADM Approach

Giordano Cintia

We develop a canonical ADM framework for gravitational backreaction during inflation. Our approach extends the formalism used to compute cosmological correlators by applying it to the evolution of the quantum background, which we identify with the metric one-point function. The aim is to assess the quantum stability of inflationary geometries under gravitational backreaction. Within this framework, the backreaction is determined by the expectation values of the Hamiltonian constraint and the equations of motion for the spatial metric. Working in the exact de Sitter limit, we apply the framework to a massless minimally coupled spectator scalar field and the physical graviton polarizations. At one loop, their backreaction renormalizes the relation between the cosmological constant and the Hubble parameter without inducing any secular departure from de Sitter evolution, in agreement with previous results. We perform the calculation using a hard momentum cutoff and show that a fixed physical cutoff allows the homogeneous background equations to be renormalized with time- and background-independent coefficients, in contrast to a fixed comoving cutoff. Finally, we demonstrate that the explicit representation of the backreaction depends on the gauge condition imposed on the metric fluctuations, as well as on the background-fluctuation split. Nevertheless, these different representations are related by a gauge transformation and are therefore physically equivalent.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Strong Constraints on Higgsino Dark Matter from Solar Capture

Maxim Pospelov and Harikrishnan Ramani

Higgsino dark matter remains one of the most convincing dark matter candidates. It can exist in a “quasi-Dirac" regime, when the splitting between two Majorana components is on the order of $O(\rm few~\,MeV)$ or less. Owing to the strong gravitational pull of the Sun, the DM particles accelerate to up to $\sim 1400$\,km/sec in the solar core, which allows for inelastic scattering on heavy elements and very effective capture onto solar-bound trajectories. We evaluate the expected flux of the neutrinos from the expected $\chi\chi \to W^+W^-,ZZ$ annihilation for the cosmologically preferred mass, $m_\chi \simeq 1.08$\,TeV while keeping the mass splitting $\delta$ as a free parameter. Confronting it with the non-observation of high-energy neutrinos from the Sun by the IceCube experiment, we obtain a robust limit, $\delta>566$\,keV. These limits exclude the interpretation of the recent LZ event in terms of endothermic inelastic scattering of Higgsino dark matter on xenon nuclei.
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Cosmology and Nongalactic Astrophysics

Gravitational Imprints of Axion Clouds on Black-Hole Orbital Dynamics

J. Ruz, V. Mungai, F. Kühnel et al. (+4 more)

Black holes of primordial or astrophysical origin immersed in axion dark matter provide a natural laboratory for exploring the interplay between compact objects and ultralight scalar fields. While previous studies have primarily focused on superradiance and horizon-scale phenomena, the gravitational response of the surrounding axion distribution has received comparatively little attention. We investigate the dynamics of particles orbiting Schwarzschild and Kerr primordial black holes embedded in scalar-field dark matter halos. Using first-order perturbation theory, we show that the ambient halo redistributes the gravitationally bound axion cloud, shifting the characteristic radius of the gravitational atom. Numerical integrations of timelike geodesics demonstrate that the maximum orbital response consistently occurs at this perturbed radius, establishing a direct correspondence between the microscopic structure of the axion wavefunction and the macroscopic dynamics of orbiting particles. Our results identify a new purely gravitational signature of scalar-field dark matter around primordial black holes and provide a framework for probing mixed axion–primordial black hole dark matter scenarios.
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All authors J. Ruz, V. Mungai, F. Kühnel, C. Köhn, E. Stamou, J. K. Vogel, B. Guichard

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Ultralight Bosons Explain the Mass-Spin Correlations in the Merging Binary Black Hole Population

Xiao-Xiao Kou, Vuk Mandic, Ran Ding et al. (+1 more)

Ultralight bosons could trigger superradiant instabilities in rapidly spinning black holes, forming oscillating clouds while extracting rotational energy. We consider an extended, superradiance-informed spin distribution model that characterizes possible environment-induced spin variations and compare its predictions with the observed population of merging black hole binaries in the Gravitational-Wave Transient Catalogs (GWTCs). We find that the mass-spin relation predicted by a scalar boson with mass $m_b\sim 10^{-12} \,\rm eV$ is consistent with the GWTCs, with increasing significance from GWTC-3.0 to 5.0. The Bayes factor reaches $\ln B \approx 7.8$ for GWTC-5.0. Intriguingly, this mass range largely coincides with a previous study based on a waveform analysis of the GW190728 gravitational wave event. Our findings provide compelling evidence that a superradiance-informed spin distribution model is highly compatible with the expanding binary black hole population dataset.
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All authors Xiao-Xiao Kou, Vuk Mandic, Ran Ding, Chi Tian

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Dark Matter as the Z_2 Partner of the Standard Model Higgs Boson

Yasunori Nomura

A possible gamma-ray excess from the Galactic halo favors dark matter with a mass of several hundred GeV. In previous work, we found that an electroweak scalar doublet is a particularly economical, and nearly uniquely selected, interpretation among simple renormalizable thermal dark-matter models. We point out that its unbroken Z_2 symmetry is exactly equivalent to an interchange symmetry between two Higgs doublets, making dark matter the Z_2-odd partner of the Standard Model Higgs boson and suggesting that the two doublets may share a common weak-scale origin. We connect this model to the recently reported 248 keV nuclear-recoil event in the LUX-ZEPLIN experiment. For dark-matter masses of 440–600 GeV, a technically natural, mass-dependent neutral-state splitting of order 350 keV defines a narrow strip near the kinematic boundary where the fixed off-diagonal Z interaction can produce the observed recoil. Because the scattering probes the extreme high-velocity tail of the Galactic distribution, this interpretation predicts a large annual modulation, with future events preferentially occurring around early summer. Neither observation is yet conclusive, but their common interpretation is sharply testable.
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Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.GA

Disc-Based Estimation of the Local Dark Matter Density and Velocity Distribution in IllustrisTNG50

Hatsume Chujo, Shogo Masaki, Keiko I. Nagao et al. (+1 more)

We study the dark matter (DM) density and velocity distribution in the solar neighborhood of Milky Way-like galaxies using the TNG50-1 run of the IllustrisTNG simulation suite. Milky Way-like galaxies are selected according to both their halo mass and their bulge-to-total stellar mass ratio, and the solar-neighborhood region within each galaxy is identified from the positions and number density of stars, so that DM particles associated with the galactic disc are extracted while contributions from the halo component are suppressed. Averaging over the selected galaxies, we obtain a local DM density of $\rho \simeq 0.47\pm0.02~{\rm GeV\,cm^{-3}}$, consistent with the range inferred from observations. The disc-based extraction gives a higher peak density, $0.41\pm0.02~{\rm GeV\,cm^{-3}}$, than the value $0.34\pm0.02~{\rm GeV\,cm^{-3}}$ from a simple distance-based extraction, probably because it excludes the low-density DM in the halo. The width of the density distribution, on the other hand, is nearly unchanged. The velocity distribution is well described by an isotropic Maxwellian with a peak velocity of about $226~{\rm km~s^{-1}}$, close to the value assumed in the standard halo model. The differences in the density and velocity distributions between our disc-based and simple distance-based extractions are not so large as to significantly affect the interpretation of direct-detection experiments.
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All authors Hatsume Chujo, Shogo Masaki, Keiko I. Nagao, Takuho Nakabayashi

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Quasicrystalline Inflation: From the Cosmological Dipole to Primordial Diffraction

Jiro Soda

We propose quasicrystalline inflation. Six quasiperiodic phases decompose into three phonons and three phasons. It turns out that a coherent pure-phason displacement can generate a local power dipole while the linear traceless quadrupole vanishes. From spatially varying quadratic effective field theory, we derive off-diagonal correlations whose momentum transfer is restricted to integer combinations of the six icosahedral wavevectors. These correlated off-diagonal signals provide a characteristic observational signature of primordial quasiperiodic order, primordial diffraction.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Cosmological implications for hairy black holes via spontaneous symmetry breaking: Are Hairy Black Holes Primordial?

Suruj Jyoti Das and Miok Park

We investigate whether hairy black holes generated through spontaneous symmetry breaking in Einstein-Scalar-Gauss-Bonnet (ESGB) theory, involving a complex scalar field with a global $U(1)$ symmetry, can be compatible with cosmological evolution. To this end, we introduce the ESGB theory with a scalar self-interaction that becomes relevant on cosmological scales while remaining negligible near the black hole. Owing to the time dependence of the GB term on cosmological scales, the scalar field dynamics in the evolving FLRW background differ qualitatively from those in the nearly static black hole background. In particular, for scalar-GB couplings compatible with hairy black hole formation, the effective potential supports a symmetry-broken vacuum throughout inflation. However, after inflation, a decelerated expansion changes the sign of the GB term, temporarily making the effective potential unbounded from below. As the GB contribution subsequently decreases, the scalar self-interaction eventually dominates and restores the symmetry. Within this schematic framework, we derive stringent constraints on the coupling strengths, the cutoff scale, and the black hole mass, which primarily arise for avoiding efficient tachyonic amplification of the scalar field perturbations during the unbounded phase. For cutoff scales compatible with both cosmological evolution and scalar hair formation, we find that only ultralight black holes with masses of the order of a few grams can develop scalar hair, identifying them as hairy primordial black holes.
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Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.IM

BICEP/Keck XXII: Analysis of the South Pole Atmosphere for CMB Observations

P. A. R. Ade, Z. Ahmed, M. Amiri et al. (+92 more)

The South Pole is among the driest sites on Earth, and the resulting high atmospheric transparency makes it an excellent site for millimeter-wave astronomical observations. Nevertheless, for bolometric surveys of the cosmic microwave background (CMB), fluctuations in line-of-sight water vapor drive variable atmospheric emission, which has a significant impact on survey sensitivity. We have deployed a water vapor radiometer (WVR) to characterize these fluctuations in space and time and to compare atmospheric and CMB signals with other sites. This WVR has been monitoring conditions from the South Pole over the past nine years, co-located and co-observing with the BICEP series of telescopes. In this work, we analyze the performance of the WVR and the characteristics of the South Pole atmosphere and demonstrate coherent wind-driven transport of water vapor structures across the site. We show that fluctuations in CMB detector timestreams are well correlated with fluctuations in atmospheric water vapor, providing independent justification for baseline filtering procedures used to remove these fluctuations and providing a new pathway to detect and mitigate the temperature-to-polarization leakage that currently limits the precision of ground-based CMB polarization measurements.
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All authors P. A. R. Ade, Z. Ahmed, M. Amiri, D. Barkats, D. Barron, R. Basu Thakur, I. Birdwell, C. A. Bischoff, D. Beck, J. J. Bock, V. Buza, B. Cantrall, J. R. Cheshire IV, J. Connors, J. Cornelison, M. Crumrine, A. J. Cukierman, E. Denison, L. Duband, M. A. Echter, M. Eiben, B. D. Elwood, S. Fatigoni, J. P. Filippini, A. Fortes, M. Gao, C. Giannakopoulos, N. Goeckner-Wald, D. C. Goldfinger, S. Gratton, J. A. Grayson, A. Greathouse, P. K. Grimes, G. Halal, M. Halpern, E. Hand, S. A. Harrison, S. Henderson, T. D. Hoang, J. Hubmayr, H. Hui, K. D. Irwin, J. H. Kang, K. S. Karkare, S. Kefeli, J. M. Kovac, C. Kuo, K. Lasko, K. Lau, M. Lautzenhiser, T. Liu, S. C. Mackey, N. Maher, K. G. Megerian, L. Minutolo, L. Moncelsi, Y. Nakato, H. T. Nguyen, R. O'Brien, S. N. Paine, A. Papen, A. Patel, M. A. Petroff, A. R. Polish, N. Precup, T. Prouve, C. Pryke, C. D. Reintsema, T. Romand, M. Salatino, A. Schillaci, B. Schmitt, C. D. Sheehy, B. Singari, A. Soliman, T. St. Germaine, A. Steiger, B. Steinbach, R. Sudiwala, G. Teply, K. L. Thompson, C. Tucker, A. D. Turner, C. Verges, A. G. Vieregg, A. Wandui, A. C. Weber, J. Willmert, C. L. Wong, W. L. K. Wu, H. Yang, C. Yu, L. Zeng, C. Zhang, S. Zhang

Cosmology and Nongalactic Astrophysics

Calculating the squeezed bispectrum in stochastic inflation by Monte Carlo simulation

Koichi Miyamoto and Yuichiro Tada

The bispectrum of cosmological perturbations is an important probe of inflation and the underlying particle physics. However, calculating it becomes challenging in inflation models where inflaton dynamics is dominated by quantum diffusion rather than slow-roll, especially in the multi-field case. In this paper, employing the stochastic-$\delta \mathcal{N}$ formalism, we propose a Monte Carlo-based method to calculate the bispectrum in the squeezed limit, as an extension of the method for the power spectrum that we previously proposed. Our method involves generating paths of inflatons' time evolution that branch only several times, avoiding nested path generation, which incurs a prohibitive computational cost. As numerical demonstrations, we apply the proposed method to single- and double-field chaotic inflation for validation, and to hybrid inflation with mild waterfall, for which, to the best of our knowledge, the bispectrum is calculated for the first time in this work.
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Cosmology and Nongalactic Astrophysics

Inflationary Magnetogenesis with $f(R,\phi)$ Coupling

Shuang Liu, Bo-yu Zhao, Yu Li et al. (+1 more)

Inflationary magnetogenesis provides a promising mechanism for generating primordial large-scale magnetic fields, but faces challenges such as the strong coupling problem and backreaction issues. In this paper, we extend the Ratra model by introducing a coupling between the electromagnetic field and the background geometry, parameterized as $K(R)I^2(\phi)$. Starting from a general action with $f^2(R,\phi)F_{\mu\nu}F^{\mu\nu}$, we adopt $f^2(R,\phi)=K(R)I^2(\phi)$ as a concrete realization. Rather than focusing on the slow-roll inflationary stage (which reduces to the standard Ratra scenario), we concentrate on the post-inflationary reheating epoch, where the broken-power-law evolution of the scale factor and coupling function across the inflation-to-reheating transition allows us to derive analytic expressions for the magnetic and electric energy density spectra. Three key theoretical constraints are imposed on the model parameter space: the strong coupling condition, the backreaction constraint, and the CMB isotropy requirement. We obtain predictions for the present-day magnetic field strength $B_0$ and coherence length $L_{c0}$ for various combinations of the inflationary energy scale $H_f$ and the reheating temperature $T_r$. By comparing with observational constraints from radio observations and Fermi-LAT gamma-ray data, we demonstrate that the inflationary energy scale $H_f$, the reheating temperature $T_r$, the parameter $\beta$, and the e-folding numbers $N_f$, $N_r$ must satisfy stringent joint constraints. This work provides a viable theoretical framework for inflationary magnetogenesis that simultaneously satisfies theoretical consistency conditions and current observational bounds, with the reheating-stage nonlinear MHD evolution serving as a crucial ingredient for producing observationally compatible magnetic fields.
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All authors Shuang Liu, Bo-yu Zhao, Yu Li, Yao-chuan Wang

Tuesday 1 September

Cosmology and Nongalactic Astrophysics

Blast.jl: Differentiable Non-Limber Power Spectra for Joint Clustering, Shear, and CMB lensing Analyses

Sofia Chiarenza, Marco Bonici, Stefano Camera et al. (+4 more)

Upcoming large-scale structure surveys require accurate theoretical predictions for angular power spectra on the largest angular scales, where the commonly used Limber approximation breaks down and multiple relativistic and observational effects become relevant. At the same time, modern cosmological analyses increasingly rely on gradient-based inference techniques, motivating the development of fast, fully differentiable algorithms. In this work, we present a major extension of Blast.jl, a numerical toolkit for the efficient computation of non-Limber angular power spectra. Building on the Chebyshev-polynomial decomposition of the original framework, the updated algorithm incorporates redshift-space distortions, magnification bias, primordial non-Gaussianity, intrinsic alignments, CMB lensing, and the integrated Sachs-Wolfe effect, while remaining fully differentiable through custom automatic differentiation rules. Despite the increased physical complexity, the algorithm retains favorable scaling by precomputing all cosmology-independent quantities. We validate the expanded framework against brute-force integration and established cosmological codes, and provide a detailed analysis of the trade-off between computational speed and precision as a function of the algorithm hyperparameters. We demonstrate the readiness of Blast.jl for gradient-based inference through a simulated likelihood analysis with LSST Y10-like mock data, recovering unbiased cosmological and nuisance parameter constraints from a 35-parameter model using gradient-based samplers.
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All authors Sofia Chiarenza, Marco Bonici, Stefano Camera, Giulio Fabbian, Carlos García-García, Alex Krolewski, Will J. Percival

Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.GA

Dark Matter Halo Tumbling Induced by Torques from Massive Mergers

Neil Ash and Monica Valluri

Dark Matter halos exhibit slow tumbling known as `figure rotation'. Figure rotation occurs in roughly $80\%$ of isolated $\Lambda$CDM halos and is relatively unaffected by baryonic feedback, making it an attractive and relatively unexplored test for $\Lambda$CDM. However, galaxy mergers are capable of exerting strong torques on a host halo's quadrupole, warranting an investigation of whether such interactions are capable of influencing figure rotation. Using isolated $N-$body simulations and 6 TNG50 halos containing MW analog galaxies, we investigate figure rotation in the context of massive mergers. For isolated galaxies we find that massive mergers elicit rotation of the host halo in both a rapid transient phase during the satellite infall with pattern speeds between $10^\circ-60^\circ$ Gyr$^{-1}$, and post-merger as a steady tumbling with pattern speeds between $2^\circ-40^\circ$ Gyr$^{-1}$ lasting for at least $6-8$ Gyr. Both transient and long-lived tumbling depend on the trajectory of the infalling satellite. We find that figure rotation can be induced by radial mergers with no orbital angular momentum, suggesting that tidal torques from the satellite are a driving mechanism. Meanwhile, TNG50 halos show quadrupole tumbling modified during major mergers in both pattern speed (3/6 halos) and rotation axis orientation (6/6 halos). Quadrupole tumbling remains stable after the last major merger in 5 of our 6 halos. Our results suggest that, rather than tracing the early tidal shear, figure rotation at present day may instead retain a dynamical memory of a halo's last major merger.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Tremaine-Gunn Control: Evading Bounds on Light Fermion Dark Matter

Joel Barir, Diego Blas, Anubhav Mathur et al. (+1 more)

Pauli exclusion is often regarded as imposing a model-independent lower bound on the mass of fermionic dark matter in galaxies. We show that dark-sector interactions can substantially weaken this conclusion. In particular, eV-scale fermions can form bound structures with the characteristic sizes and densities of dwarf galaxies, thereby circumventing the conventional Tremaine-Gunn mass constraint. Within these objects, the degeneracy pressure is balanced by an attractive finite-range scalar Yukawa force that is significantly stronger than gravity. The interaction acts on dwarf-galaxy scales while remaining screened on larger scales. We derive the evolution of the resulting dark-matter fluid and identify a viable cosmological history in which structures first form gravitationally, with the new interaction becoming active only at late times. As a proof of concept, we construct a model in which a single late-time phase transition generates the required dynamics. These results provide a new route to exceptionally light fermionic dark matter and demonstrate that dark-sector interactions can qualitatively alter conventional phase-space limits.
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All authors Joel Barir, Diego Blas, Anubhav Mathur, Tomer Volansky

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Primordial Black Hole Assisted Dirac Leptogenesis

Marco Manno and Anish Ghoshal

Dirac leptogenesis offers a qualitatively different route to the baryon asymmetry: total lepton number is conserved, but equal and opposite asymmetries are stored in the Standard Model and right handed neutrino sectors, with only the visible component processed by electroweak sphalerons. We present the first dedicated study of how evaporating primordial black holes (PBHs) modify this mechanism. In a minimal charged-scalar mediator setup, we solve the coupled Boltzmann system including thermal production, Hawking emission of the mediator $X$ and of right handed neutrinos, the PBH contribution to the expansion rate, and entropy injection. We find that Hawking emission can populate $X$ in regions where thermal production is inefficient, allowing its subsequent CP-violating decays to enhance the baryon asymmetry. For representative benchmarks, PBHs extend the successful region from mediator masses around $10^9\,{\rm GeV}$ down to about $10^6\,{\rm GeV}$ and can compensate for smaller effective CP asymmetries. This effect is not universal: where thermal Dirac leptogenesis is already efficient, PBHs can instead reduce the final asymmetry. Their evaporation also deposits energy in the right handed neutrino sector and contributes to $\Delta N_{\rm eff}$. In the PBH parameter scan, part of the region that reproduces the observed baryon asymmetry lies below the Planck reference level $\Delta N_{\rm eff}=0.284$ and above the projected CMB-S4 sensitivity $\Delta N_{\rm eff}=0.06$.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Axion Quality from Exact Proton Stability

Joe Davighi, Admir Greljo and Xavier Ponce Díaz

A discrete, anomaly-free $\mathbb Z_9$ gauge symmetry may persist to the deep infrared, exactly forbidding proton decay. This $\mathbb Z_9$ can emerge from Higgsing a lepton-flavour non-universal $U(1)_X$ that generates realistic neutrino masses and mixings through a high-scale seesaw and predicts an additional light Goldstone. Adding an anomaly-free chiral heavy-quark sector turns this mode into the QCD axion. The same selection rules that ban proton decay also forbid PQ-violating operators below a suitably high dimension, $d_{\rm PQ}\gtrsim10$, including operators involving the heavy quarks that radiatively match onto the scalar potential. We construct explicit models viable when PQ breaking occurs before or after inflation; in the latter case, avoiding stable heavy relics and eliminating the string-wall network tightly constrain the heavy-quark spectrum. We identify restricted regions of parameter space where thermal leptogenesis remains viable and, for $d_{\rm PQ}\geq13$, can coexist with a high-quality axion constituting all of the dark matter.
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Cosmology and Nongalactic Astrophysics · Cross-listed from astro-ph.GA

JWST Reveals a Candidate Supermassive Black Hole Binary at z=4.3 in the Brightest Sub-millimeter Galaxy in COSMOS-Web

Jed McKinney, Ansh Gupta, Julian B. Munoz et al. (+13 more)

We present JWST/NIRSpec PRISM and G395M grating spectroscopy for AzTEC-1, a massive sub-mm bright galaxy at $z=4.34$ in the COSMOS extragalactic field. The PRISM spectrum reveals strong H$\alpha$, a significant Balmer break, and no H$\beta$ detection, indicating a $100-400$ Myr-old stellar population and high dust attenuation. BPT line ratios indicate the presence of an Active Galactic Nucleus (AGN). Decomposing narrow and broad line components, we recover broad, blueshifted H$\alpha$ with a velocity offset of $1245{\,\rm km\,s^{-1}}$ from the systemic narrow line velocity and with FWHM$\,\sim2500\,{\rm km\,s^{-1}}$. AzTEC-1's smooth morphology and stellar age is suggestive of a past merger-induced starburst period that would have brought in a second supermassive black hole, raising the possibility for a binary supermassive black hole system. In this scenario, we assume that the lower mass black hole hosts a broad line region orbiting a quiescent primary. Evidence for an extended outflow is not found in the 2D spectrum, NIRCam imaging, resolved ALMA observations of dust continuum, or CO, [C II]$_{157\,\mu \rm m}$ and [N II]$_{\rm 205\,\mu m}$ kinematics. AzTEC-1's high central gas mass surface density and dynamically unstable gas disk indicates that massive gas clouds external to the candidate binary SMBH's orbit might have played a role in stalling infall from $\sim10$ Myr to $\sim100$ Myr through dynamical torques, which has been theorized to occur in the nuclei of massive galaxies like AzTEC-1. If the supermassive black hole binary is confirmed, AzTEC-1 would be an excellent laboratory into the astrophysics driving low-frequency gravitational wave detections.
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All authors Jed McKinney, Ansh Gupta, Julian B. Munoz, John Chisholm, Caitlin M. Casey, Stephanie M. Urbano Stawinski, Olivia Cooper, Erini Lambrides, Hollis Akins, Maximilien Franco, Archana Aravindan, Seiji Fujimoto, Kohei Inayoshi, Andreas L. Faisst, Jeyhan S. Kartaltepe, Michael Boylan-Kolchin