Axel Widmark
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View article: Using Simulation-based Inference on Tidally Perturbed Dwarf Galaxies: The Dynamics of NGC 205
Using Simulation-based Inference on Tidally Perturbed Dwarf Galaxies: The Dynamics of NGC 205 Open
We develop a novel approach to performing precision inference on tidally perturbed dwarf galaxies. We use a Bayesian inference framework of implicit likelihood inference, previously applied mainly in the field of cosmology, based on forwar…
View article: Super-Kamiokande Strongly Constrains Leptophilic Dark Matter Capture in the Sun
Super-Kamiokande Strongly Constrains Leptophilic Dark Matter Capture in the Sun Open
The Sun can efficiently capture leptophilic dark matter that scatters with free electrons. If this dark matter subsequently annihilates into leptonic states, it can produce a detectable neutrino flux. Using 10 years of Super-Kamiokande obs…
View article: Using simulation based inference on tidally perturbed dwarf galaxies: the dynamics of NGC205
Using simulation based inference on tidally perturbed dwarf galaxies: the dynamics of NGC205 Open
We develop a novel approach to performing precision inference on tidally perturbed dwarf galaxies. We use a Bayesian inference framework of implicit likelihood inference, previously applied mainly in the field of cosmology, based on forwar…
View article: Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background
Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background Open
Recent studies indicate that thermally produced dark matter will form highly concentrated, low-mass cusps in the early universe that often survive until the present. While these cusps contain a small fraction of the dark matter, their high…
View article: First spiral arm detection using dynamical mass measurements of the Milky Way disk
First spiral arm detection using dynamical mass measurements of the Milky Way disk Open
We applied the vertical Jeans equation to the Milky Way disk in order to study non-axisymmetric variations in the thin disk surface density. We divided the disk plane into area cells with a 100 pc grid spacing and used four separate subset…
View article: Fuzzy dark matter dynamics in tidally perturbed dwarf spheroidal galaxy satellites
Fuzzy dark matter dynamics in tidally perturbed dwarf spheroidal galaxy satellites Open
Fuzzy dark matter (FDM) has dynamical properties that differ significantly from cold dark matter (CDM). These dynamical differences are strongly manifested on the spatial scale of dwarf spheroidal galaxies (dSphs), which roughly correspond…
View article: First spiral arm detection using dynamical mass measurements of the Milky Way disk
First spiral arm detection using dynamical mass measurements of the Milky Way disk Open
We apply the vertical Jeans equation to the Milky Way disk, in order to study non-axisymmetric variations in the thin disk surface density. We divide the disk plane into area cells with a 100 pc grid spacing, and use four separate subsets …
View article: The missing radial velocities of <i>Gaia</i>: a catalogue of Bayesian estimates for DR3
The missing radial velocities of <i>Gaia</i>: a catalogue of Bayesian estimates for DR3 Open
In an earlier work, we demonstrated the effectiveness of Bayesian neural networks in estimating the missing line-of-sight velocities of Gaia stars, and published an accompanying catalogue of blind predictions for the line-of-sight velociti…
View article: Fuzzy dark matter dynamics in tidally perturbed dwarf spheroidal galaxy satellites
Fuzzy dark matter dynamics in tidally perturbed dwarf spheroidal galaxy satellites Open
Fuzzy dark matter (FDM) has dynamical properties that differ significantly from cold dark matter (CDM). These dynamical differences are strongly manifested on the spatial scale of dwarf spheroidal galaxies (dSphs), which roughly correspond…
View article: The missing radial velocities of Gaia: a catalogue of Bayesian estimates for DR3
The missing radial velocities of Gaia: a catalogue of Bayesian estimates for DR3 Open
In an earlier work, we demonstrated the effectiveness of Bayesian neural networks in estimating the missing line-of-sight velocities of Gaia stars, and published an accompanying catalogue of blind predictions for the line-of-sight velociti…
View article: Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background
Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background Open
Recent studies indicate that thermally produced dark matter will form highly concentrated, low-mass cusps in the early universe that often survive until the present. While these cusps contain a small fraction of the dark matter, their high…
View article: Mapping Milky Way disk perturbations in stellar number density and vertical velocity using <i>Gaia</i> DR3
Mapping Milky Way disk perturbations in stellar number density and vertical velocity using <i>Gaia</i> DR3 Open
We have mapped the number density and mean vertical velocity of the Milky Way’s stellar disk out to roughly two kiloparsecs from the Sun using Gaia Data Release 3 (DR3) and complementary photo-astrometric distance information from StarHors…
View article: The missing radial velocities of <i>Gaia</i>: Blind predictions for DR3
The missing radial velocities of <i>Gaia</i>: Blind predictions for DR3 Open
While Gaia has observed the phase space coordinates of over a billion stars in the Galaxy, in the overwhelming majority of cases it has only obtained five of the six coordinates, the missing dimension being the radial (line-of-sight) veloc…
View article: Weighing the Local Interstellar Medium using Gamma Rays and Dust
Weighing the Local Interstellar Medium using Gamma Rays and Dust Open
Cold gas forms a significant mass fraction of the Milky Way disk, but is its most uncertain baryonic component. The density and distribution of cold gas is of critical importance for Milky Way dynamics, as well as models of stellar and gal…
View article: Mapping Milky Way disk perturbations in stellar number density and vertical velocity using Gaia DR3
Mapping Milky Way disk perturbations in stellar number density and vertical velocity using Gaia DR3 Open
We have mapped the number density and mean vertical velocity of the Milky Way's stellar disk out to roughly two kiloparsecs from the Sun using Gaia Data Release 3 (DR3) and complementary photo-astrometric distance information from StarHors…
View article: The missing radial velocities of Gaia: blind predictions for DR3
The missing radial velocities of Gaia: blind predictions for DR3 Open
While Gaia has observed the phase space coordinates of over a billion stars in the Galaxy, in the overwhelming majority of cases it has only obtained five of the six coordinates, the missing dimension being the radial (line-of-sight) veloc…
View article: Weighing the Galactic disk using phase-space spirals
Weighing the Galactic disk using phase-space spirals Open
We have applied our method to weigh the Galactic disk using phase-space spirals to the proper motion sample of Gaia ’s early third release (EDR3). For stars in distant regions of the Galactic disk, the latitudinal proper motion has a close…
View article: Weighing the Galactic disk using phase-space spirals
Weighing the Galactic disk using phase-space spirals Open
In this fourth article on weighing the Galactic disk using the shape of the phase-space spiral, we have tested our method on a billion particle three-dimensional N -body simulation, comprised of a Milky Way like host galaxy and a merging d…
View article: Snowmass2021 Cosmic Frontier White Paper: Dark Matter Physics from Halo Measurements
Snowmass2021 Cosmic Frontier White Paper: Dark Matter Physics from Halo Measurements Open
The non-linear process of cosmic structure formation produces gravitationally bound overdensities of dark matter known as halos. The abundances, density profiles, ellipticities, and spins of these halos can be tied to the underlying fundam…
View article: Estimating the local dark matter density in a non-axisymmetric wobbling disc
Estimating the local dark matter density in a non-axisymmetric wobbling disc Open
The density of dark matter near the Sun, ρDM, ⊙, is important for experiments hunting for dark matter particles in the laboratory, and for constraining the local shape of the Milky Way’s dark matter halo. Estimates to date have typically a…
View article: Weighing the Galactic disk using phase-space spirals IV. Tests on a three-dimensional galaxy simulation
Weighing the Galactic disk using phase-space spirals IV. Tests on a three-dimensional galaxy simulation Open
In this fourth article on weighing the Galactic disk using the shape of the phase-space spiral, we have tested our method on a billion particle three-dimensional N-body simulation, comprised of a Milky Way like host galaxy and a merging dw…
View article: Weighing the Galactic disk using phase-space spirals III. Probing distant regions of the disk using the Gaia EDR3 proper motion sample
Weighing the Galactic disk using phase-space spirals III. Probing distant regions of the disk using the Gaia EDR3 proper motion sample Open
We have applied our method for weighing the Galactic disk using phase-space spirals to the Gaia EDR3 proper motion sample. For stars in distant regions of the Galactic disk, the latitudinal proper motion has a close projection with vertica…
View article: Dark matter local density determination: recent observations and future prospects
Dark matter local density determination: recent observations and future prospects Open
This report summarises progress made in estimating the local density of dark matter ($ρ_{\mathrm{DM,\odot}}$), a quantity that is especially important for dark matter direct detection experiments. We outline and compare the most common met…
View article: Weighing the Galactic disk using phase-space spirals
Weighing the Galactic disk using phase-space spirals Open
Using the method that was developed in the first paper of this series, we measured the vertical gravitational potential of the Galactic disk from the time-varying structure of the phase-space spiral, using data from Gaia as well as supplem…
View article: Weighing the Galactic disk using phase-space spirals II. Most stringent constraints to a thin dark disk using Gaia EDR3
Weighing the Galactic disk using phase-space spirals II. Most stringent constraints to a thin dark disk using Gaia EDR3 Open
Using the method that was developed in the first paper of this series, we measure the vertical gravitational potential of the Galactic disk from the time-varying structure of the phase-space spiral, using data from Gaia as well as suppleme…
View article: Weighing the Galactic disk using phase-space spirals
Weighing the Galactic disk using phase-space spirals Open
We present a new method for inferring the gravitational potential of the Galactic disk, using the time-varying structure of a phase-space spiral in the ( z , w )-plane (where z and w represent vertical position and vertical velocity). Our …
View article: Weighing the Galactic disk using phase-space spirals I. Tests on one-dimensional simulations
Weighing the Galactic disk using phase-space spirals I. Tests on one-dimensional simulations Open
We present a new method for inferring the gravitational potential of the Galactic disk, using the time-varying structure of a phase-space spiral in the $(z,w)$-plane (where $z$ and $w$ represent vertical position and vertical velocity). Ou…
View article: Dark matter local density determination: recent observations and future prospects
Dark matter local density determination: recent observations and future prospects Open
This report summarises progress made in estimating the local density of dark matter ($\rho_{\mathrm{DM,\odot}}$), a quantity that is especially important for dark matter direct detection experiments. We outline and compare the most common …
View article: Measuring the matter density of the Galactic disc using stellar streams
Measuring the matter density of the Galactic disc using stellar streams Open
We present a novel method for determining the total matter surface density of the Galactic disc by analysing the kinematics of a dynamically cold stellar stream that passes through or close to the Galactic plane. The method relies on the f…
View article: Measuring the local matter density using <i>Gaia</i> DR2 <i>(Corrigendum)</i>
Measuring the local matter density using <i>Gaia</i> DR2 <i>(Corrigendum)</i> Open