We analyze X-ray spatial and spectral data on the giant elliptical galaxy NGC 4472, the brightest galaxy in the Virgo cluster. The X-ray contours of NGC 4472 are elongated in the northeast-southwest direction, perhaps as a result of motion through the Virgo intracluster gas. A bow shock-like structure is evident on the galaxy's north side. The temperature at a given radius in this bow shock region is slightly higher than the temperature at the same radius on the galaxy's southwest side. Away from this bow shock region, the surface brightness profile of NGC 4472 can be traced out to a radius of 260 kpc in the southwest direction. Beyond 260 kpc, we find evidence for emission from both the Virgo cluster and the Galactic North Polar Spur (believed to be the rim of a hot Galactic superbubble). NGC 4472 is interacting with the dwarf irregular galaxy UGC 7636. We do not detect any excess or deficit in the X-ray emission toward this galaxy. An H i cloud, detected previously in the 21 cm line and located midway between the two galaxies, appears to have been removed from the irregular galaxy through either tidal interaction or ram pressure stripping. We find a marginally significant hole in the ROSAT HRI and PSPC X-ray images at the position of this cloud, suggesting that the cloud lies at the front side of NGC 4472. If the hole in the X-ray images is due to soft X-ray absorption, the total gaseous mass of the cloud must be at least 1.7 × 109 M☉, far greater than its 21 cm H I mass. This suggests that the majority of the material in the cloud is molecular.
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机译：我们分析了处女座星团中最亮的星系-巨大的椭圆星系NGC 4472的X射线空间和光谱数据。 NGC 4472的X射线轮廓沿东北-西南方向拉长，这可能是通过处女座星团内部气体运动的结果。在银河系的北侧可以看到类似弓震动的结构。在该弓形冲击区域内给定半径处的温度略高于银河系西南侧相同半径处的温度。远离该弓形冲击区域，NGC 4472的表面亮度分布可以沿西南方向绘制到260 kpc的半径。超过260 kpc时，我们发现了处女座星团和银河系北极极星（据信是热的银河系超气泡的边缘）都有发射的证据。 NGC 4472正在与不规则矮星系UGC 7636相互作用。我们没有检测到向该星系发射X射线的任何过量或不足。先前在21 cm线中检测到并位于两个星系中间的H i云似乎已通过潮汐相互作用或冲撞压力剥离从不规则星系中移除。我们在该云层的位置的ROSAT HRI和PSPC X射线图像中发现了一个边缘明显的孔，这表明该云层位于NGC 4472的正面。如果X射线图像中的孔是由于软X射线吸收后，云的总气体质量必须至少为1.7×109M☉，远大于其21 cm HI质量。这表明云中的大多数物质是分子。
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