论文标题
X射线和SZ明亮的分散源朝向M31：当地的热桥
An X-ray and SZ bright diffuse source toward M31: a Local Hot Bridge
论文作者
论文摘要
我们报告了X射线和Sunyaev-Zeldovich（SZ）的大规模（$ r \ \ circ $ \ 20^\ Circ $） - 对M31的Bright Bright扩散增强，这可能是将银河系（MW）与M31连接起来的本地热桥。我们从全天空的O VII和O VIII发射线测量调查中减去银河发射，发现这两个离子的发射在M31左右的$ r \ of20^\ Circ $之内增强。平均排放增强功能为$ 5.6 \ pm 1.3 $ L.U.和$ 2.8 \ pm0.6 $ L.U.对于O VII和O VIII（两个离子的$>4σ$）。我们还提取围绕M31的SZ信号，这表明表面亮度$ y $ $ $ $ $ $ 2-4 \ times10^{ - 7} $，增强$>2.5σ$（并且最适合$5.9σ$）。这三个测量值用温度$ \ log〜t（{\ rm k}）> 6 $跟踪热气，显示了类似的平稳形状（$ \ of courc $ of $ \ lift oct $ \ ofc $ of $ \ \ oct of circ $）。单相假设导致$ \ log〜t（{\ rm k}）= 6.34 \ pm0.03 $的温度，该温度由O VII/O VIII线比率确定。结合X射线和SZ测量值，我们建议此功能不太可能是M31（太大）或MW（太高压力和X射线明亮）周围的热光晕。高原形状可以通过连接MW和M31（当地热桥）的气缸来解释。我们将其长度限制为约400 kpc，半径为120 kpc，密度为$ \ 2 \ times10^{ - 4} -10^{ - 3}〜\ rm cm^{ - 3} $，金属金属的金属性为$ 0.02-0.1〜z___ \ odot $。 baryon质量为$ \ gtrsim10^{11} 〜m_ \ odot $，氧气质量约为$ \ gtrsim10^8〜m_ \ odot $，这有助于本地集团的巴里昂或金属预算。
We report a large-scale ($r\approx 20^\circ$) X-ray and Sunyaev-Zeldovich (SZ)-bright diffuse enhancement toward M31, which might be a Local Hot Bridge connecting the Milky Way (MW) with M31. We subtract the Galactic emission from the all-sky O VII and O VIII emission line measurement survey, and find that the emission of these two ions is enhanced within $r\approx20^\circ$ around M31. The mean emission enhancements are $5.6\pm 1.3$ L.U., and $2.8\pm0.6$ L.U. for O VII and O VIII, respectively ($>4σ$ for both ions). We also extract the SZ signal around M31, which suggests a surface brightness $y$ of $2-4\times10^{-7}$, an enhancement $>2.5σ$ (and a best fit of $5.9σ$). These three measurements trace the hot gas with a temperature $\log~T({\rm K})> 6$, showing similar plateau shapes (flat within $\approx15^\circ$, and zero beyond $\approx30^\circ$). A single-phase assumption leads to a temperature of $\log~T({\rm K})=6.34\pm0.03$, which is determined by the O VII/O VIII line ratio. Combining X-ray and SZ measurements, we suggest that this feature is unlikely to be the hot halo around M31 (too massive) or in the MW (too high pressure and X-ray bright). The plateau shape may be explained by a cylinder connecting the MW and M31 (the Local Hot Bridge). We constrain its length to be about 400 kpc, with a radius of 120 kpc, a density of $\approx 2\times10^{-4}-10^{-3} ~\rm cm^{-3}$, and a metallicity of $0.02-0.1~ Z_\odot$. The baryon mass is $\gtrsim10^{11}~M_\odot$, and the oxygen mass is about $\gtrsim10^8~M_\odot$, which contribute to the baryon or metal budget of the Local Group.
