Metal enrichment in the Fermi bubbles as a probe of their origin

Yoshiyuki Inoue, Shinya Nakashima, Masaya Tahara, Jun Kataoka, Tomonori Totani, Yutaka Fujita, Yoshiaki Sofue

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    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 nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, 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 patterns 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.

    Original languageEnglish
    Article number56
    JournalPublications of the Astronomical Society of Japan
    Volume67
    Issue number3
    DOIs
    Publication statusPublished - 2015 Apr 8

    Fingerprint

    bubble
    bubbles
    probe
    active galactic nuclei
    probes
    metal
    metals
    gamma rays
    metallicity
    star formation
    starburst galaxies
    ejecta
    supernovae
    histories
    injection
    galaxies
    cooling
    timescale
    stars
    history

    Keywords

    • abundances-Galaxy
    • center-Galaxy
    • Galaxy
    • halo-X-rays
    • ISM

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Metal enrichment in the Fermi bubbles as a probe of their origin. / Inoue, Yoshiyuki; Nakashima, Shinya; Tahara, Masaya; Kataoka, Jun; Totani, Tomonori; Fujita, Yutaka; Sofue, Yoshiaki.

    In: Publications of the Astronomical Society of Japan, Vol. 67, No. 3, 56, 08.04.2015.

    Research output: Contribution to journalArticle

    Inoue, Yoshiyuki ; Nakashima, Shinya ; Tahara, Masaya ; Kataoka, Jun ; Totani, Tomonori ; Fujita, Yutaka ; Sofue, Yoshiaki. / Metal enrichment in the Fermi bubbles as a probe of their origin. In: Publications of the Astronomical Society of Japan. 2015 ; Vol. 67, No. 3.
    @article{e04e32570173466d8c03926be89f0859,
    title = "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 nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, 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 patterns 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.",
    keywords = "abundances-Galaxy, center-Galaxy, Galaxy, halo-X-rays, ISM",
    author = "Yoshiyuki Inoue and Shinya Nakashima and Masaya Tahara and Jun Kataoka and Tomonori Totani and Yutaka Fujita and Yoshiaki Sofue",
    year = "2015",
    month = "4",
    day = "8",
    doi = "10.1093/pasj/psv032",
    language = "English",
    volume = "67",
    journal = "Publication of the Astronomical Society of Japan",
    issn = "0004-6264",
    publisher = "Astronomical Society of Japan",
    number = "3",

    }

    TY - JOUR

    T1 - Metal enrichment in the Fermi bubbles as a probe of their origin

    AU - Inoue, Yoshiyuki

    AU - Nakashima, Shinya

    AU - Tahara, Masaya

    AU - Kataoka, Jun

    AU - Totani, Tomonori

    AU - Fujita, Yutaka

    AU - Sofue, Yoshiaki

    PY - 2015/4/8

    Y1 - 2015/4/8

    N2 - 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 nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, 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 patterns 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.

    AB - 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 nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, 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 patterns 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.

    KW - abundances-Galaxy

    KW - center-Galaxy

    KW - Galaxy

    KW - halo-X-rays

    KW - ISM

    UR - http://www.scopus.com/inward/record.url?scp=84930719903&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84930719903&partnerID=8YFLogxK

    U2 - 10.1093/pasj/psv032

    DO - 10.1093/pasj/psv032

    M3 - Article

    VL - 67

    JO - Publication of the Astronomical Society of Japan

    JF - Publication of the Astronomical Society of Japan

    SN - 0004-6264

    IS - 3

    M1 - 56

    ER -