标题： ROSAT 对雕塑家星系 NGC7793 的观测 显示英文标题

标题： ROSAT observations of the Sculptor galaxy NGC7793

摘要： 我们在此报告用ROSAT PSPC对距我们非常近（距离为3.38 Mpc）的雕塑家星系NGC7793周围区域进行光谱成像观测的结果。 在该区域内检测到许多点源，其中一些显示出变化的证据。 有七个源位于该系统的光学界限内，最亮的一个（Lx ~ 9×10³⁸ erg/s），位于NGC7793的南缘。 这个源也被观察到是变化的，现在不再认为与之前认为的z=0.071红移类星体有关。 NGC7793盘内的其他一些源可能是由于X射线双星、超新星遗迹或星系本身的超级气泡。 其他源可能与背景活动星系核有关。 除了点源发射外，在NGC7793及其周围检测到相当均匀且未分辨的发射，延伸至大约4千秒差距的半径。 这种发射可能在一定程度上受到未分辨点源的污染，因为它的温度（kT~1 keV）比其他附近螺旋星系中的弥散气体成分要热得多。 将NGC7793的X射线特性与其他雕塑家星系团成员进行比较表明，就活跃程度而言，它可能介于其宁静和星爆邻居之间。 显示英文摘要

摘要： We report here the results of spectral imaging observations with the ROSAT PSPC of the field surrounding the very nearby (D=3.38 Mpc) Sculptor galaxy, NGC7793. Many point sources are detected within the field, several of them showing evidence for variability. Seven sources are seen to lie within the optical confines of the system, the brightest (Lx ~ 9x10e38 erg/s), lying to the southern edge of NGC7793. This source, also observed to be variable, is seen now, not to be associated with a z=0.071 redshift QSO, as was previously thought. A number of the other sources within the NGC7793 disc are likely to be due to X-ray binaries, supernova remnants or superbubbles within the galaxy itself. Other sources may be associated with background AGN. In addition to the point source emission, rather uniform unresolved emission is detected in and around NGC7793 extending to a radius of perhaps 4 kpc. This emission is likely to be contaminated to some degree by unresolved point sources, as its temperature (kT~1 keV) is rather hotter than is seen for the diffuse gas components in other nearby spiral galaxies. Comparing the X-ray properties of NGC7793 with those of the remaining Sculptor group members, suggests that it may, in terms of activity, lie somewhere between its quiescent and starburst neighbours.