ALMA CO Observations of the Mixed-Morphology Supernova Remnant W49B: Efficient Production of Recombining Plasma and Hadronic Gamma-rays via Shock-Cloud Interactions

Abstract

We carried out new CO($J$ = 2-1) observations toward the mixed-morphology supernova remnant (SNR) W49B with the Atacama Large Millimeter/submillimeter Array (ALMA). We found that CO clouds at $\sim$10 km s${}^{-1}$ show a good spatial correspondence with synchrotron radio continuum as well as an X-ray deformed shell. The bulk mass of molecular clouds accounts for the western part of the shell, not for the eastern shell where near-infrared H${}_2$ emission is detected. The molecular clouds at $\sim$10 km s${}^{-1}$ show higher kinetic temperature of $\sim$20-60 K, suggesting that modest shock-heating occurred. The expanding motion of the clouds with $\Delta V\sim$6 km s${}^{-1}$ was formed by strong winds from the progenitor system. We argue that the barrel-like structure of Fe rich ejecta was possibly formed not only by an asymmetric explosion, but also by interactions with dense molecular clouds. We also found a negative correlation between the CO intensity and the electron temperature of recombining plasma, implying that the origin of the high-temperature recombining plasma in W49B can be understood as the thermal conduction model. The total energy of accelerated cosmic-ray protons $W_{\mathrm{p}}$ is estimated to be $\sim$$2\times 10^{49}$ erg by adopting an averaged gas density of $\sim$$650\pm 200$ cm${}^{-3}$. The SNR age-$W_{\mathrm{p}}$ diagram indicates that W49B shows one of the highest in-situ values of $W_{\mathrm{p}}$ in the gamma-ray bright SNRs.

19 pages, 10 figures, 2 tables, published in The Astrophysical Journal (ApJ)

References in corpus (31)

• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) I: Project Overview and Initial Results
• Discriminating the Progenitor Type of Supernova Remnants with Iron K-Shell Emission
• Gamma rays from molecular clouds
• AUTO-MULTITHRESH: A General Purpose Automasking Algorithm
• A Near-Infrared and X-ray Study of W49B: A Wind Cavity Explosion
• The Slow X-Ray Expansion of the Northwestern Rim of the Supernova Remnant RX J0852.0-4622
• Interstellar protons in the TeV gamma-ray SNR HESS J1731-347:Possible evidence for the coexistence of hadronic and leptonic gamma-rays
• Supernova remnant W49B and its environment
• A detailed study of the interstellar protons toward the TeV $\gamma$-ray SNR RX J0852.0$-$4622 (G266.2$-$1.2, Vela Jr.); a third case of the $\gamma$-rays and ISM spatial correspondence
• Numerical Simulations of Supernova Remnant Evolution in a Cloudy Interstellar Medium
• Non-equilibrium ionization in mixed-morphology supernova remnants
• Deep XMM-Newton Observations Reveal the Origin of Recombining Plasma in the Supernova Remnant W44
• APEX observations of supernova remnants - I. Non-stationary MHD-shocks in W44
• Toward the Understanding of the Physical Origin of Recombining Plasma in the Supernova Remnant IC 443
• On the gamma-ray emission of W44 and its surroundings
• High-resolution Near-infrared Spectroscopic Study of Galactic Supernova Remnants. I. Kinematic Distances
• Survey of Ionized Gas of the Galaxy, Made with the Arecibo telescope (SIGGMA): Inner Galaxy Data Release
• ALMA CO Observations of the Gamma-Ray Supernova Remnant RX J1713.7-3946: Discovery of Shocked Molecular Cloudlets and Filaments at 0.01 pc scales
• Localized Recombining Plasma in G166.0+4.3: A Supernova Remnant with an Unusual Morphology
• The interstellar medium in young supernova remnants: key to the production of cosmic X-rays and $\gamma$-rays
• Global Distribution of Ionizing and Recombining Plasmas in the Supernova Remnant G290.1$-$0.8
• Analysis of XMM-Newton Observations of Supernova Remnant W49B and Clues to the Progenitor
• Atlas of CO-Line Shells and Cavities around Galactic Supernova Remnants with FUGIN
• SNR G39.2-0.3, an Hadronic Cosmic Rays Accelerator
• New Scenario of plasma evolution in IC 443
• Interstellar anatomy of the TeV gamma-ray peak in the IC443 supernova remnant
• X-ray spectra of Sgr A East and diffuse X-ray background near the Galactic center
• Recombining Plasma & Gamma-ray Emission in the Mixed-morphology Supernova Remnant 3C 400.2
• Dark supernova remnant
• Discovery of recombining plasma associated with the candidate supernova remnant G189.6+3.3 with Suzaku

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