Suzaku X-ray observations of the fermi bubbles: Northernmost cap and southeast claw discovered with MAXI-SSC

M. Tahara, J. Kataoka, Y. Takeuchi, T. Totani, Y. Sofue, J. S. Hiraga, H. Tsunemi, Y. Inoue, M. Kimura, C. C. Cheung, S. Nakashima

    研究成果: Article査読

    20 被引用数 (Scopus)


    We report on Suzaku observations of large-scale X-ray structures possibly related to the Fermi Bubbles obtained in 2013 with a total duration of ≃80 ks. The observed regions were (1) the northern cap (N-cap; l ∼ 0°, 45° < b< 55°) seen in the mid-band (1.7-4.0 keV) map recently provided by Monitor of All-sky X-ray Image Solid-state Slit Camera (MAXI-SSC) and (2) the southeast claw (SE-claw; l ∼ 10°, -20° < b < -10°) seen in the ROSAT all-sky map and MAXI-SSC low-band (0.7-1.7 keV) map. In each region, we detected diffuse X-ray emission, which is represented by a three-component plasma model consisting of an unabsorbed thermal component (kT ≃ 0.1 keV) from the Local Hot Bubble, absorbed kT = 0.30 ± 0.05 keV emission representing the Galactic halo (GH), and a power-law component due to the isotropic cosmic X-ray background radiation. The emission measure of the GH component in the SE-claw shows an excess by a factor of ≃2.5 over the surrounding emission at 2° away. We also found a broad excess in the 1.7-4.0 keV count rates across the N-cap after compiling other archival data from Suzaku and Swift. The spectral stacking analysis of the N-cap data indicates the presence of another thermal component with kT = 0.70-0.11+0.22keV. The temperature kT ≃ 0.3 keV of the GH is higher than the ubiquitous value of kT ≃ 0.2 keV near the Fermi bubbles, and can be even higher (∼0.7 keV). We discuss our findings in the context of the bubble-halo interaction.

    ジャーナルAstrophysical Journal
    出版ステータスPublished - 2015 4月 1

    ASJC Scopus subject areas

    • 天文学と天体物理学
    • 宇宙惑星科学


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