Weighing the Local Interstellar Medium using Gamma Rays and Dust

Abstract

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 galactic evolution. Previous studies have used correlations between gas and dust to obtain high-resolution measurements of cold gas, but with large normalization uncertainties. We present a novel approach that uses Fermi-LAT $\gamma$-ray data to measure the total gas density, achieving a similar precision as previous works, but with independent systematic uncertainties. Notably, our results have sufficient precision to probe the range of results obtained by current world-leading experiments.

arXiv comment5 pages, 3 figures; appendix adds 13 pages, 6 figures; in review for PRL

References in corpus (81)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Gaia Data Release 2. Summary of the contents and survey properties
• MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics
• Interstellar Dust Grains
• The CO-to-H2 Conversion Factor
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Fermi Large Area Telescope Fourth Source Catalog
• A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• The Interstellar Environment of our Galaxy
• Monte Carlo treatment of hadronic interactions in enhanced Pomeron scheme: I. QGSJET-II model
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• Production and propagation of cosmic-ray positrons and electrons
• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• The Dark Molecular Gas
• Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range
• Diffuse continuum gamma rays from the Galaxy
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• Pulsars as the Sources of High Energy Cosmic Ray Positrons
• The Local Dark Matter Density
• Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data
• Fermi-LAT Observations of High-Energy Gamma-Ray Emission Toward the Galactic Center
• Gaia-2MASS 3D maps of Galactic interstellar dust within 3 kpc
• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• The Evolution of ISM Mass Probed by Dust Emission -- ALMA Observations at z = 0.3 to 2
• Stars, Gas, and Dark Matter in the Solar Neighborhood
• On the Relationship Between Molecular Hydrogen and Carbon Monoxide Abundances in Molecular Clouds
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• Planck 2013 results. XIII. Galactic CO emission
• The cold interstellar medium of galaxies in the Local Universe
• A Large Catalog of Accurate Distances to Molecular Clouds from PS1 Photometry
• Dark matter local density determination: recent observations and future prospects
• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
• A new, large-scale map of interstellar reddening derived from HI emission
• Galactic cosmic rays after the AMS-02 observations
• Radial distribution of the diffuse gamma-ray emissivity in the galactic disk
• The 21-SPONGE HI Absorption Line Survey II: The temperature of Galactic HI
• AMS-02 beryllium data and its implication for cosmic ray transport
• High-Energy Gamma Rays from the Milky Way: Three-Dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium
• Current status and desired accuracy of the isotopic production cross sections relevant to astrophysics of cosmic rays I. Li, Be, B, C, N
• Constraints on the distribution of supernova remnants with Galactocentric radius
• Inference of the Local Interstellar Spectra of Cosmic Ray Nuclei Z<=28 with the GalProp-HelMod Framework
• 3D Distribution of Molecular Gas in the Barred Milky Way
• Cosmic-ray transport from AMS-02 B/C data: benchmark models and interpretation
• Constraining a Thin Dark Matter Disk with Gaia
• N(H I)/E(B-V)
• Large-Scale Model of the Milky Way: Stellar Kinematics and Microlensing Event Timescale Distribution in the Galactic Bulge
• Galactic cosmic-ray propagation in the light of AMS-02: I. Analysis of protons, helium, and antiprotons
• The Three-Dimensional Spatial Distribution of Interstellar Gas in the Milky Way: Implications for Cosmic Rays and High-Energy Gamma-Ray Emissions
• Constraining Galactic cosmic-ray parameters with Z<=2 nuclei
• Galactic halo size in the light of recent AMS-02 data
• Diffractive Interaction and Scaling Violation in pp->pi^0 Interaction and GeV Excess in Galactic Diffuse Gamma-Ray Spectrum of EGRET
• Fitting B/C cosmic-ray data in the AMS-02 era: A cookbook
• Solar and nuclear physics uncertainties in cosmic-ray propagation
• Power requirements for cosmic ray propagation models involving diffusive reacceleration; estimates and implications for the damping of interstellar turbulence
• Implications of Lithium to Oxygen AMS-02 spectra on our understanding of cosmic-ray diffusion
• Implications of current nuclear cross sections on secondary cosmic rays with the upcoming DRAGON2 code
• AAfrag: Interpolation routines for Monte Carlo results on secondary production in proton-proton, proton-nucleus and nucleus-nucleus interactions
• A Far Ultraviolet Spectroscopic Explorer Survey of Interstellar Molecular Hydrogen in the Galactic Disk
• Gamma rays as probes of cosmic-ray propagation and interactions in galaxies
• Improved Cosmic-Ray Injection Models and the Galactic Center Gamma-Ray Excess
• JINGLE, a JCMT legacy survey of dust and gas for galaxy evolution studies: I. Survey overview and first results
• Revisiting Spatial-Dependent Propagation Model with Latest Observations of Cosmic Ray Nuclei
• Markov chain Monte Carlo analyses of the flux ratios of B, Be and Li with the DRAGON2 code
• HI filaments are cold and associated with dark molecular gas. HI4PI based estimates of the local diffuse CO-dark H2 distribution
• Simulating the Galactic Multi-messenger Emissions with HERMES
• The effect of FIR emission from SDSS galaxies on the SFD Galactic extinction map
• On the progressive hardening of the cosmic-ray proton spectrum in the inner Galaxy
• Interstellar Gas and a Dark Disk
• Physical properties of CO-dark molecular gas traced by C${}^{+}$
• Constraints on the spatially dependent cosmic-ray propagation model from Bayesian Analysis
• Testing the universality of cosmic-ray nuclei from protons to oxygen with AMS-02
• Revisit cosmic ray propagation by using ${}^1$H, ${}^2$H, ${}^3$He and ${}^4$He
• Intermediate mass and heavy Galactic cosmic-ray nuclei: the case of new AMS-02 measurements
• Bayesian inference of three-dimensional gas maps: II. Galactic HI
• Variations between Dust and Gas in the Diffuse Interstellar Medium. 2. Search for Cold Gas
• Diffuse Gamma Rays in 3D Galactic Cosmic-ray Propagation Models

Cited by in corpus (3)

• Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background
• New determination of the neutrino hadronic production cross sections from GeV to beyond PeV energies
• The influence of the 3D Galactic gas structure on cosmic-ray transport and $\gamma$-ray emission