Metal Enrichment in the Fermi Bubbles as a Probe of Their Origin

Abstract

The Fermi bubbles are gigantic gamma-ray structures in our Galaxy. The physical origin of the bubbles is still under debate. The leading scenarios can be divided into two categories. One is the nuclear star forming activity similar to extragalactic starburst galaxies and the other is the past active galactic nucleus (AGN) like activity of the Galactic center supermassive black hole. In this paper, we propose that metal abundance measurements will provide an important clue to probe their origin. Based on a simple spherically symmetric bubble model, we find that the generated metallicity and abundance pattern of the bubbles' gas strongly depend on assumed star formation or AGN activities. Star formation scenarios predict higher metallicities and abundance ratios of [O/Fe] and [Ne/Fe] than AGN scenarios do because of supernovae ejecta. Furthermore, the resultant abundance depends on the gamma-ray emission process because different mass injection histories are required for the different gamma-ray emission processes due to the acceleration and cooling time scales of non-thermal particles. Future X-ray missions such as ASTRO-H and Athena will give a clue to probe the origin of the bubbles through abundance measurements with their high energy resolution instruments.

arXiv comment6 pages, 1 figure, accepted for publication in PASJ

References in corpus (51)

• The chemical composition of the Sun
• On the variation of the Initial Mass Function
• Nucleosynthesis in Chandrasekhar Mass Models for Type Ia Supernovae and Constraints on Progenitor Systems and Burning-Front Propagation
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Galactic chemical evolution: Carbon through Zinc
• Nucleosynthesis Yields of Core-Collapse Supernovae and Hypernovae, and Galactic Chemical Evolution
• The supernova rate per unit mass
• The power of blazar jets
• Supernova feedback efficiency and mass loading in the starburst and galactic superwind exemplar M82
• The Spectrum and Morphology of the Fermi Bubbles
• Microwave ISM Emission Observed by WMAP
• Supernova Nucleosynthesis in Population III 13 -- 50 $M_{\odot }$ Stars and Abundance Patterns of Extremely Metal-Poor Stars
• The Large-scale Bipolar Wind in the Galactic Center
• The Fermi Haze: A Gamma-Ray Counterpart to the Microwave Haze
• Delay Time Distribution Measurement of Type Ia Supernovae by the Subaru/XMM-Newton Deep Survey and Implications for the Progenitor
• The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays
• The Structure of the Milky Way's Hot Gas Halo
• Extended Anomalous Foreground Emission in the WMAP 3-Year Data
• Chandra observations of NGC 253. II: On the origin of diffuse X-ray emission in the halos of starburst galaxies
• Giant Magnetized Outflows from the Centre of the Milky Way
• The Cosmic Core-collapse Supernova Rate does not match the Massive-Star Formation Rate
• On Pair Content and Variability of Sub-Parsec Jets in Quasars
• The Fermi Bubbles. I. Possible Evidence for Recent AGN Jet Activity in the Galaxy
• Are quasar jets dominated by Poynting flux?
• Iron Emission Lines from Extended X-ray Jets in SS 433: Reheating of Atomic Nuclei
• Yields of rotating stars at solar metallicity
• The Milky Way's Fermi Bubbles: Echoes of the Last Quasar Outburst?
• Origin of the Fermi Bubble
• Fermi gamma-ray `bubbles' from stochastic acceleration of electrons
• Suzaku observations of the diffuse x-ray emission across the fermi bubbles' edges
• Modelling Element Abundances in Semi-analytic Models of Galaxy Formation
• The ASTRO-H X-ray Observatory
• ASCA Observations of the Supernova Remnant IC 443: Thermal Structure and Detection of Overionized Plasma
• Three classical Cepheid variable stars in the nuclear bulge of the Milky Way
• A RIAF Interpretation for the Past Higher Activity of the Galactic Center Black Hole and the 511 keV Annihilation Emission
• Fermi Bubbles Inflated by Winds Launched from the Hot Accretion Flow in Sgr A*
• The K-shell Line Distribution of Heavy Elements along the Galactic Plane Observed with Suzaku
• Evidence for Gamma-ray Jets in the Milky Way
• Non-Thermal Insights on Mass and Energy Flows Through the Galactic Centre and into the Fermi Bubbles
• The Fermi Bubbles. II. The Potential Roles of Viscosity and Cosmic Ray Diffusion in Jet Models
• The Fermi Bubbles as Starburst Wind Termination Shocks
• The Fermi Bubbles: Gamma-ray, Microwave, and Polarization Signatures of Leptonic AGN Jets
• X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line
• Discovery of the recombining plasma in the south of the Galactic center; a relic of the past Galactic center activity?
• Revealing Type Ia supernova physics with cosmic rates and nuclear gamma rays
• The Fermi Bubbles as a Scaled-up Version of Supernova Remnants
• A Hadronic-Leptonic Model for the Fermi Bubbles: Cosmic-Rays in the Galactic Halo and Radio Emission
• High Resolution X-ray Spectroscopy of the Local Hot Gas along the 3C 273 Sightline
• Steady-State Hadronic Gamma-Ray Emission from 100-Myr-Old Fermi Bubbles
• Fermi bubble $\gamma$-rays as a result of diffusive injection of Galactic cosmic rays
• Structual Study of Galactic Hot Gas toward Markarian 421 from X-Ray Absorption and Emission Lines

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• The Interaction of the Fermi Bubbles with the Milky Way's Hot Gas Halo
• X-ray and Gamma-ray Observations of the Fermi Bubbles and NPS/Loop I Structures
• Unveiling the Origin of the Fermi Bubbles
• Galactic-Center Hyper-Shell Model for the North Polar Spurs
• A magnetised Galactic halo from inner Galaxy outflows
• Interaction of the Galactic-Centre Super Bubbles with the Gaseous Disc
• Diffuse x-ray emission from the northern arc of loop I observed with suzaku
• Evidence for powerful winds and the associated reverse shock as the origin of the Fermi bubbles