ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-ionized and Photoionized Nebulae

Sano H, Matsumura H, Nagaya T, Yamane Y, Alsaberi RZE, Filipovic MD, Tachihara K, Fujii K, Tokuda K, Tsuge K, Yoshiike S, Onishi T, Kawamura A, Minamidani T, Mizuno N, Yamamoto H, Inutsuka S, Inoue T, Maxted N, Rowell G, Sasaki M, Fukui Y (2019)


Publication Type: Journal article

Publication year: 2019

Journal

Book Volume: 873

Journal Issue: 1

DOI: 10.3847/1538-4357/ab02fd

Abstract

We carried out new (CO)-C-12(J = 1-0, 3-2) observations of a N63A supernova remnant (SNR) from the LMC using the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Submillimeter Telescope Experiment. We find three giant molecular clouds toward the northeast, east, and near the center of the SNR. Using the ALMA data, we spatially resolved clumpy molecular clouds embedded within the optical nebulae in both the shock-ionized and photoionized lobes discovered by previous H alpha and [S II] observations. The total mass of the molecular clouds is similar to 800 M-circle dot for the shock-ionized region and similar to 1700 M-circle dot for the photoionized region. Spatially resolved X-ray spectroscopy reveals that the absorbing column densities toward the molecular clouds are similar to(1.5-6.0) x 10(21) cm(-2), which are similar to 1.5-15 times less than the averaged interstellar proton column densities for each region. This means that the X-rays are produced not only behind the molecular clouds, but also in front of them. We conclude that the dense molecular clouds have been completely engulfed by the shock waves, but have still survived erosion owing to their high density and short interacting time. The X-ray spectrum toward the gas clumps is well explained by an absorbed power-law model or a high-temperature plasma model, in addition to thermal plasma components, implying that the shock-cloud interaction is efficiently working for both cases through the shock ionization and magnetic field amplification. If the hadronic gamma-ray is dominant in the GeV. band, the total energy of the cosmic-ray protons is calculated to be similar to(0.3-1.4) x 10(49) erg, with an estimated interstellar proton density of similar to 190 +/- 90 cm(-3), containing both the shock-ionized gas and neutral atomic hydrogen.

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APA:

Sano, H., Matsumura, H., Nagaya, T., Yamane, Y., Alsaberi, R.Z.E., Filipovic, M.D.,... Fukui, Y. (2019). ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-ionized and Photoionized Nebulae. Astrophysical Journal, 873(1). https://dx.doi.org/10.3847/1538-4357/ab02fd

MLA:

Sano, H., et al. "ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-ionized and Photoionized Nebulae." Astrophysical Journal 873.1 (2019).

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