Philip F. Hopkins
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View article: Cosmic-ray Perpendicular Superdiffusion and Parallel Mirror Diffusion in a Partially Ionized and Turbulent Medium
Cosmic-ray Perpendicular Superdiffusion and Parallel Mirror Diffusion in a Partially Ionized and Turbulent Medium Open
Understanding cosmic-ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel transport in turbulent, partially ionized media using high-re…
View article: Further correction to the STARFORGE methods paper: Planck-mean dust opacities
Further correction to the STARFORGE methods paper: Planck-mean dust opacities Open
The model for the Planck-mean dust opacity $κ_{P}$ given in Appendix C of the STARFORGE simulations methods paper does not extrapolate well to low radiation temperature $T_{\rm rad}$, so we provide an updated calculation suitable for gener…
View article: Bridging scales: How much do supermassive black holes grow in the suppressed Bondi regime?
Bridging scales: How much do supermassive black holes grow in the suppressed Bondi regime? Open
The co-evolution of supermassive black holes (SMBHs) and their host galaxies remains one of the central open questions in cosmology, rooted in the coupling between accretion, feedback, and the multi-scale physics that links the event horiz…
View article: Igniting galaxy formation in the post-reionization universe
Igniting galaxy formation in the post-reionization universe Open
It is widely believed that the ultraviolet background produced during the epoch of reionization conspires against the formation of low-mass galaxies. Indeed, this mechanism is often invoked as a solution to the so-called `missing satellite…
View article: Connecting Cores and Black Hole Dynamics across Scales: From Globular Clusters to Massive Ellipticals
Connecting Cores and Black Hole Dynamics across Scales: From Globular Clusters to Massive Ellipticals Open
The centers of massive elliptical galaxies exhibit a wide range in density profiles, from central cusps to resolved cores with order kiloparsec sizes. The cored ellipticals have been linked to the presence of supermassive black hole binari…
View article: X-Ray Emission Signatures of Galactic Feedback in the Hot Circumgalactic Medium: Predictions from Cosmological Hydrodynamical Simulations
X-Ray Emission Signatures of Galactic Feedback in the Hot Circumgalactic Medium: Predictions from Cosmological Hydrodynamical Simulations Open
Little is currently known about the physical properties of the hot circumgalactic medium (CGM) surrounding massive galaxies. Next-generation X-ray observatories will enable detailed studies of the hot CGM in emission. To support these futu…
View article: Discs no more: the morphology of low-mass simulated galaxies in FIREbox
Discs no more: the morphology of low-mass simulated galaxies in FIREbox Open
We study the morphology of hundreds of simulated central galaxies in the stellar mass range $M_\star =$ 107.5–1011 $\rm M_\odot$ from the FIREbox cosmological volume. We demonstrate that FIREbox is able to predict a wide variety of morphol…
View article: The role of galactic winds fueling central starbursts and quasars in the FIRE cosmological simulations
The role of galactic winds fueling central starbursts and quasars in the FIRE cosmological simulations Open
Central starbursts and Active Galactic Nuclei (AGN) are thought to be fueled by either galaxy interactions or secular processes in gravitationally unstable discs. We employ cosmological hydrodynamic simulations from the Feedback in Realist…
View article: Connecting Cores and Black Hole Dynamics Across Scales: From Globular Clusters to Massive Ellipticals
Connecting Cores and Black Hole Dynamics Across Scales: From Globular Clusters to Massive Ellipticals Open
The centers of massive elliptical galaxies exhibit a wide range in density profiles, from central cusps to resolved cores with order kiloparsec sizes. The cored ellipticals have been linked to the presence of supermassive black hole binari…
View article: Microphysical Regulation of Non-Ideal MHD in Weakly-Ionized Systems: Does the Hall Effect Matter?
Microphysical Regulation of Non-Ideal MHD in Weakly-Ionized Systems: Does the Hall Effect Matter? Open
The magnetohydrodynamics (MHD) equations plus ‘non-ideal’ (Ohmic, Hall, ambipolar) resistivities are widely used to model weakly-ionized astrophysical systems. We show that if gradients in the magnetic field become too steep, the implied c…
View article: Galactic Center Gamma-Ray Emission in MHD Galaxy Formation Simulations with Full Cosmic Ray Spectra
Galactic Center Gamma-Ray Emission in MHD Galaxy Formation Simulations with Full Cosmic Ray Spectra Open
The Milky Way's galactic center is a highly dynamical, crowded environment. Gamma ray observations of this region, such as the excess of GeV scale gamma rays observed by Fermi LAT, have been of tremendous interest to both the high energy a…
View article: Central densities of dark matter haloes in <scp>fire-2</scp> simulations of low-mass galaxies with cold dark matter and self-interacting dark matter
Central densities of dark matter haloes in <span>fire-2</span> simulations of low-mass galaxies with cold dark matter and self-interacting dark matter Open
We investigate the central density structure of dark matter haloes in cold dark matter (CDM) and self-interacting dark matter (SIDM) models using simulations that are part of the Feedback In Realistic Environments (fire) project. For simul…
View article: Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation
Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation Open
We present the first infrared spectral predictions from a self-consistent simulation of the formation of a quasar in a starburst galaxy, spanning cosmological to innermost stable circular orbit (ISCO) scales. The infrared emission is domin…
View article: Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models
Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models Open
Recent years have seen many arguments for cosmic rays (CRs) as an important influence on galactic and circumgalactic (CGM) physics, star and galaxy formation. We present a pedagogical overview of state-of-the-art modeling of CR-magnetohydr…
View article: Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission
Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission Open
X-ray bright cool-core (CC) clusters contain luminous radio sources accelerating cosmic ray (CR) leptons at prodigious rates. Near the acceleration region, high-energy leptons produce synchrotron (mini)halos and sometimes observable gamma …
View article: Connection between galaxy morphology and dark-matter halo structure I: a running threshold for thin discs and size predictors from the dark sector
Connection between galaxy morphology and dark-matter halo structure I: a running threshold for thin discs and size predictors from the dark sector Open
We study the connection between galaxy morphology and host dark matter (DM) halo structure using cosmological simulations. Introducing a new kinematic decomposition scheme, we robustly separate thin and thick discs and measure halo propert…
View article: Why catch when you can throw? A framework for tagging animals without capture or restraint
Why catch when you can throw? A framework for tagging animals without capture or restraint Open
The use of electronic tags has significantly advanced our understanding of wild animal behaviour and physiology. However, traditional tagging methods often require capturing and restraining or sedating animals, which causes stress and may …
View article: Cosmic Rays Masquerading as Hot CGM Gas: An Inverse-Compton Origin for Diffuse X-ray Emission in the Circumgalactic Medium
Cosmic Rays Masquerading as Hot CGM Gas: An Inverse-Compton Origin for Diffuse X-ray Emission in the Circumgalactic Medium Open
Observations from ROSAT and eROSITA have argued that Milky Way (MW), Andromeda, and lower-mass galaxies exhibit extended soft X-ray ( keV) diffuse halos out to radii kpc in the circumgalactic medium (CGM). If interpreted as thermal…
View article: The Physical Origin of Positive Metallicity Radial Gradients in High-redshift Galaxies: Insights from the FIRE-2 Cosmological Hydrodynamic Simulations
The Physical Origin of Positive Metallicity Radial Gradients in High-redshift Galaxies: Insights from the FIRE-2 Cosmological Hydrodynamic Simulations Open
Using the FIRE-2 cosmological zoom-in simulations, we investigate the temporal evolution of gas-phase metallicity radial gradients of Milky Way–mass progenitors in the redshift range of 0.4 < z < 3. We pay special attention to the occurren…
View article: The Physical Origin of Positive Metallicity Radial Gradients in High-redshift Galaxies: Insights from the FIRE-2 Cosmological Hydrodynamic Simulations
The Physical Origin of Positive Metallicity Radial Gradients in High-redshift Galaxies: Insights from the FIRE-2 Cosmological Hydrodynamic Simulations Open
Using the FIRE-2 cosmological zoom-in simulations, we investigate the temporal evolution of gas-phase metallicity radial gradients of Milky Way–mass progenitors in the redshift range of 0.4 < z < 3. We pay special attention to the occurren…
View article: Cosmic Ray Feedback in Massive Halos: Implications for the Distribution of Baryons
Cosmic Ray Feedback in Massive Halos: Implications for the Distribution of Baryons Open
We use order of magnitude estimates and observational constraints to argue that feedback from relativistic cosmic rays (CRs) produced by massive black holes is likely to have a particularly large effect at radii of order the virial radius …
View article: Constraining cosmic ray transport models using circumgalactic medium properties and observables
Constraining cosmic ray transport models using circumgalactic medium properties and observables Open
Cosmic rays (CRs) are a pivotal non-thermal component of galaxy formation and evolution. However, the intricacies of CR physics, particularly how they propagate in the circumgalactic medium (CGM), remain largely unconstrained. In this work…
View article: Dust Battery: A Novel Mechanism for Seed Magnetic Field Generation in the Early Universe
Dust Battery: A Novel Mechanism for Seed Magnetic Field Generation in the Early Universe Open
We propose a novel dust battery mechanism for generating seed magnetic fields in the early Universe, in which charged dust grains are radiatively accelerated, inducing strong electric currents that subsequently generate magnetic fields. Ou…
View article: Cosmic Ray Perpendicular Superdiffusion and Parallel Mirror Diffusion in a Partially Ionized and Turbulent Medium
Cosmic Ray Perpendicular Superdiffusion and Parallel Mirror Diffusion in a Partially Ionized and Turbulent Medium Open
Understanding cosmic ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel transport in turbulent, partially ionized media using high-re…
View article: Multi-Phase Thermal Structure & The Origin of the Broad-Line Region, Torus, and Corona in Magnetically-Dominated Accretion Disks
Multi-Phase Thermal Structure & The Origin of the Broad-Line Region, Torus, and Corona in Magnetically-Dominated Accretion Disks Open
Recent simulations have demonstrated the formation of ‘flux-frozen’ and hyper-magnetized disks, qualitatively distinct from both classical disks and magnetically-arrested disks, as a natural consequence of fueling gas to supermassive bla…
View article: The Importance of Subtleties in the Scaling of the ‘Terminal Momentum’ For Galaxy Formation Simulations
The Importance of Subtleties in the Scaling of the ‘Terminal Momentum’ For Galaxy Formation Simulations Open
In galaxy formation simulations, it is increasingly common to represent supernovae (SNe) at finite resolution (when the Sedov-Taylor phase is unresolved) via hybrid energy-momentum coupling with some ‘terminal momentum’ (depending weakly o…
View article: Zooming In On The Multi-Phase Structure of Magnetically-Dominated Quasar Disks: Radiation From Torus to ISCO Across Accretion Rates
Zooming In On The Multi-Phase Structure of Magnetically-Dominated Quasar Disks: Radiation From Torus to ISCO Across Accretion Rates Open
Recent radiation-thermochemical-magnetohydrodynamic simulations resolved formation of quasar accretion disks from cosmological scales down to ~300 gravitational radii , arguing they were ‘hyper-magnetized’ (plasma supported by tor…
View article: Rapid, strongly magnetized accretion in the zero-net-vertical-flux shearing box
Rapid, strongly magnetized accretion in the zero-net-vertical-flux shearing box Open
We show that there exist two qualitatively distinct turbulent states of the zero-net-vertical-flux shearing box. The first, which has been studied in detail previously, is characterized by a weakly magnetized ( ) midplane with slow pe…
View article: Effects of Galactic Environment on Size and Dark Matter Content in Low-mass Galaxies
Effects of Galactic Environment on Size and Dark Matter Content in Low-mass Galaxies Open
We utilize the cosmological volume simulation FIREbox to investigate how a galaxy’s environment influences its size and dark matter content. Our study focuses on approximately 1200 galaxies (886 central and 332 satellite halos) in the low-…
View article: Galactic-scale Feeding Reveals Warped Hypermagnetized Multiphase Circumbinary Accretion Around Supermassive Black Hole Binaries
Galactic-scale Feeding Reveals Warped Hypermagnetized Multiphase Circumbinary Accretion Around Supermassive Black Hole Binaries Open
Supermassive black hole (SMBH) binaries in gaseous and stellar environments are prime targets for next-generation space-based gravitational wave detectors. Yet, realistic accretion conditions under which these binary systems evolve are not…