Optical and near-ir spectrophotometry of the galaxy ngc 3310
Optical and near-ir spectrophotometry of the galaxy ngc 3310
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NGC 3310 星系的光学和近红外分光光度测量
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
Á. D́ıaz
中科院分区：
文献类型：
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作者：
M. Pastoriza;H. Dottori;E. Terlevich;R. Terlevich;Á. D́ıaz
已经获得了NGC 1068星系核周环中16个恒星形成区域在λλ 3500–9200 A范围内的分光光度信息。其中8个区域的Hα光度高于4 1039 erg s−1 cm−2，因此它们可以被置于观测到的最亮的HII区域之一。在 16 个研究区域中的 10 个区域中，肯定存在 Cat 红外吸收线。在其中 7 个区域中，测量的等效宽度低于 7 A，而在其他三个区域中，获得了更高的值（7.3、8.6、8.7）。在这三种情况下，这些谱线可能起源于红超巨星群。如果我们将CaT和Ha等效宽度与理论模型（Leitherer & Heckmann 1995, ApJS, 96, 9; Leitherer et al. 1999, ApJSS, 123, 3L）进行比较，我们发现CaT等效宽度值较低的区域位于代表Salpeter初始质量函数的6.5 Myr单爆发模型的线上。对于那些具有最高等效宽度值的恒星，数据可以通过电离气体的年轻恒星 (2 – 8 Myr) 和负责观测到的 CatT 的较老恒星 (15 – 20 Myr) 的混合群体来重现。
Spectrophotometric information in the range λλ 3500–9200 A has been obtained for 16 of the star forming regions in the circumnuclear ring of the galaxy NGC 1068. In 8 of these regions, the Hα luminosity is higher than 4 1039 erg s−1 cm−2, so they can be placed among the most luminous HII regions observed. In 10 of the 16 studied regions, the CaT infrared absortion lines are definitely present. In 7 of these regions the measured equivalent width is lower than 7 A, while in the other three, higher values are obtained (7.3, 8.6, 8.7). In these three cases, the lines might have their origin in a population of red supergiant stars. If we compare the CaT and the Ha equivalent width with theoretical models (Leitherer & Heckmann 1995, ApJS, 96, 9; Leitherer et al. 1999, ApJSS, 123, 3L), we find that the regions with low values of the CaT equivalent width are on the line standing for a 6.5 Myr single burst model of Salpeter initial mass function. For those with the highest values of the equivalent width, the data could be reproduced by a mixed population of young stars (2 – 8 Myr) ionizing the gas, and older ones (15 – 20 Myr) responsible for the CaT observed.