Observations of a Magellanic Corona

Article

关键词: FUSE SURVEY;    TOTAL MASS;    IONIZATION;    VELOCITY;    CLOUDS;    GAS;    ABSORPTION;    HYDROGEN;    DWARFS;   

DOI  :  10.1038/s41586-022-05090-5

来源: SCIE

【 摘 要 】

The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the closest massive satellite galaxies of the Milky Way. They are probably on their first passage on an infalling orbit towards our Galaxy(1) and trace the continuing dynamics of the Local Group(2). Recent measurements of a high mass for the LMC (M-halo approximate to 10(11.1-11.4) M-circle dot)(3-6) imply that the LMC should host a Magellanic Corona: a collisionally ionized, warm-hot gaseous halo at the virial temperature (10(5.3-5.5) K) initially extending out to the virial radius (100-130 kiloparsecs (kpc)). Such a corona would have shaped the formation of the Magellanic Stream(7), a tidal gas structure extending over 200 degrees across the sky(2,8,9) that is bringing in metal-poor gas to the Milky Way(10). Here we show evidence for this Magellanic Corona with a potential direct detection in highly ionized oxygen (O+5) and indirectly by means of triply ionized carbon and silicon, seen in ultraviolet (UV) absorption towards background quasars. We find that the Magellanic Corona is part of a pervasive multiphase Magellanic circumgalactic medium (CGM) seen in many ionization states with a declining projected radial profile out to at least 35 kpc from the LMC and a total ionized CGM mass of log(10)(M-H II,M-CGM/M-circle dot) approximate to 9.1 +/- 0.2. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic group and its nested evolution with the Local Group.

【 授权许可】

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