标题： HII区域的裂隙观测和经验计算 显示英文标题

标题： Slit Observations and Empirical Calculations for HII Regions

摘要： 在分析电离氢区（HII区）时，系统误差的一个可能来源是用于观测的狭缝尺寸有限，这会对经验推导出的物理量产生影响。 通过Aangaba代码构建了一组光致电离模型，该模型改变了由恒星团簇发射的电离辐射谱以及气体丰度。 然后使用计算出的谱线面亮度来模拟狭缝观测，并利用文献中描述的常用方法推导经验参数。 根据狭缝覆盖物体的比例，这些参数可能与从整个物体观测得到的参数不同，这种效应主要取决于电离恒星团簇的年龄。 低电离禁戒线比高电离禁戒线或再结合线对狭缝覆盖区域的大小更为敏感。 至于温度指示剂T[OIII]，狭缝效应较小，因为该温度是从[OIII]线推导出来的。 另一方面，对于依赖于[OII]线的丰度指示剂R23，狭缝效应略高。 因此，由于狭缝观测引起的氧丰度系统误差较低，通常小于10%，但当电离光子数量相对较少（13.6到54.4电子伏特之间）的恒星团簇驱动的HII区会形成较小的O++发射体积时除外。 在这种情况下，当覆盖面积小于50%时，从狭缝观测推导出的经验氧丰度的系统误差将超过10%。 显示英文摘要

摘要： When analysing HII regions, a possible source of systematic error on empirically derived physical quantities is the limited size of the slit used for the observations. A grid of photoionization models was built through the Aangaba code varying the ionizing radiation spectrum emitted by a stellar cluster, as well as the gas abundance. The calculated line surface brightness was then used to simulate slit observations and to derive empirical parameters using the usual methods described in the literature. Depending on the fraction of the object covered by the slit, the parameters can be different from those obtained from observations of the whole object, an effect that is mainly dependent on the age of the ionizing stellar cluster. The low-ionization forbidden lines are more sensitive to the size of the area covered by the slit than the high-ionization forbidden lines or recombination lines. Regarding the temperature indicator T[OIII], the slit effects are small since this temperature is derived from [OIII] lines. On the other hand, for the abundance indicator R23, which depends also on the [OII] line, the slit effect is slightly higher. Therefore, the systematic error due to slit observations on the O abundance is low, being usually less than 10%, except for HII regions powered by stellar clusters with a relative low number of ionizing photons between 13.6 and 54.4 eV, which create a smaller O++ emitting volume. In this case, the systematic error on the empirical O abundance deduced from slit observations is more than 10% when the covered area is less than 50%.