Maximum Entropy Estimation of the Galactic Bulge Morphology via the VVV Red Clump

Abstract

The abundance and narrow magnitude dispersion of Red Clump (RC) stars make them a popular candidate for mapping the morphology of the bulge region of the Milky Way. Using an estimate of the RC's intrinsic luminosity function, we extracted the three-dimensional density distribution of the RC from deep photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey. We used maximum entropy based deconvolution to extract the spatial distribution of the bulge from Ks-band star counts. We obtained our extrapolated non-parametric model of the bulge over the inner 40 by 40 degrees squared region of the Galactic centre. Our reconstruction also naturally matches onto a parametric fit to the bulge outside the VVV region and inpaints overcrowded and high extinction regions. We found a range of bulge properties consistent with other recent investigations based on the VVV data. In particular, we estimated the bulge mass to be in the range 13 to 17 billion solar masses, the X-component to be between 18% and 25% of the bulge mass, and the bulge angle with respect to the Sun-Galactic centre line to be between 18 and 32 degrees. Studies of the Fermi Large Area Telescope (LAT) gamma-ray Galactic centre excess suggests that the excess may be traced by Galactic bulge distributed sources. We applied our deconvolved density in a template fitting analysis of this Fermi-LAT GeV excess and found an improvement in the fit compared to previous parametric based templates.

arXiv comment25 pages, 27 figures, minor typo corrected

References in corpus (52)

• Galactic Stellar and Substellar Initial Mass Function
• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• A new generation of PARSEC-COLIBRI stellar isochrones including the TP-AGB phase
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• A geometric distance measurement to the Galactic Center black hole with 0.3% uncertainty
• Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission
• Dark Matter and Pulsar Model Constraints from Galactic Center Fermi-LAT Gamma Ray Observations
• The Fermi Galactic Center GeV Excess and Implications for Dark Matter
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• The Metal Content of Bulge Field Stars from FLAMES-GIRAFFE Spectra. I. Stellar parameters and Iron Abundances
• Galaxia: a code to generate a synthetic survey of the Milky Way
• COBE's Galactic Bar and Disk
• Two Red Clumps and the X-Shaped Milky Way Bulge
• Spiral arms, bar shape and bulge microlensing in the Milky Way
• Stellar populations in the Milky Way bulge region : Towards solving the Galactic bulge and bar shapes using 2MASS data
• The Split Red Clump of the Galactic Bulge from OGLE-III
• Evolutionary synthesis of stellar populations: a modular tool
• Modelling the Galactic Bar Using Red Clump Giants
• Possible Evidence For Dark Matter Annihilation In The Inner Milky Way From The Fermi Gamma Ray Space Telescope
• The Consistency of Fermi-LAT Observations of the Galactic Center with a Millisecond Pulsar Population in the Central Stellar Cluster
• Made-to-Measure models of the Galactic Box/Peanut bulge: stellar and total mass in the bulge region
• Modelling the Galactic bar using OGLE-II Red Clump Giant Stars
• Constraining the thick disc formation scenario of the Milky Way
• The GIRAFFE Inner Bulge Survey (GIBS) III. Metallicity distributions and kinematics of 26 Galactic bulge fields
• Mapping the X-Shaped Milky Way Bulge
• Galactic Bulge Preferred Over Dark Matter for the Galactic Center Gamma-Ray Excess
• A New Photometric Model of the Galactic Bar using Red Clump Giants
• High-Energy Gamma Rays from the Milky Way: Three-Dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium
• The Fermi-LAT GeV Excess Traces Stellar Mass in the Galactic Bulge
• Milky Way mass galaxies with X-shaped bulges are not rare in the local Universe
• Challenges in Explaining the Galactic Center Gamma-Ray Excess with Millisecond Pulsars
• Strong Evidence that the Galactic Bulge is Shining in Gamma Rays
• A parametric description of the 3D structure of the Galactic Bar/Bulge using the VVV survey
• Microlensing Optical Depth of the COBE Bulge
• The Gamma-Ray Luminosity Function of Millisecond Pulsars and Implications for the GeV Excess
• Quantifying the (X/Peanut)-Shaped Structure in Edge-on Disc Galaxies: Length, Strength, and Nested Peanuts
• Testing asteroseismology with Gaia DR2: Hierarchical models of the Red Clump
• The Gaia DR2 parallax zero point: Hierarchical modeling of red clump stars
• N-body simulation insights into the X-shaped bulge of the Milky Way: Kinematics and distance to the Galactic Centre
• Transverse kinematics of the Galactic bar-bulge from VVV and Gaia
• The Bulge Metallicity Distribution from the APOGEE Survey
• SkyFACT: High-dimensional modeling of gamma-ray emission with adaptive templates and penalized likelihoods
• Consistency Between the Luminosity Function of Resolved Millisecond Pulsars and the Galactic Center Excess
• The structure behind the Galactic bar traced by red clump stars in the VVV survey
• Bayesian Model Comparison and Analysis of the Galactic Disk Population of Gamma-Ray Millisecond Pulsars
• On the optimal calibration of VVV photometry
• New insight on the origin of the double red clump in the Milky Way bulge
• Assembling the Milky Way bulge from globular clusters: Evidence from the double red clump
• A case against an X-shaped structure in the Milky Way young bulge
• Mapping the stellar age of the Milky Way bulge with the VVV. II. Deep JKs catalogs release based on PSF photometry

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• The characteristics of the Galactic center excess measured with 11 years of Fermi-LAT data
• The stellar mass distribution of the Milky Way's bar: an analytic model
• Age Demographics of the Milky Way Disk and Bulge
• Testing kinematic distances under a realistic Galactic potential
• Comparing the Galactic Bulge and Galactic Disk Millisecond Pulsars
• Luminosity functions consistent with a pulsar-dominated Galactic Center Excess
• Cherenkov Telescope Array sensitivity to the putative millisecond pulsar population responsible for the Galactic center excess
• Robust inference of the Galactic centre gamma-ray excess spatial properties
• Robustness of the Galactic Center Excess Morphology Against Masking
• The Andromeda Gamma-Ray Excess: Background Systematics of the Millisecond Pulsars and Dark Matter Interpretations
• A New Determination of the Millisecond Pulsar Gamma-Ray Luminosity Function and Implications for the Galactic Center Gamma-Ray Excess
• Non-Parametric Density Reconstruction of the Galactic Bulge Area using Red Clump Stars in the VVV Survey
• The effect of kick velocities on the spatial distribution of millisecond pulsars and implications for the Galactic center excess
• Applying Simulation-Based Inference to Spectral and Spatial Information from the Galactic Center Gamma-Ray Excess
• Observations of the Fermi bubbles and the Galactic center excess with the DArk Matter Particle Explorer
• Assessing the Impact of Hydrogen Absorption on the Characteristics of the Galactic Center Excess