The B-band luminosities of quasar host galaxies
The B-band luminosities of quasar host galaxies
复制标题
类星体主星系的 B 波段光度
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
L. Wisotzki
中科院分区：
文献类型：
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作者：
K. Jahnke;L. Wisotzki
我们报告了对从汉堡/ESO巡天中选择的57个低红移准星体（类星体/QSO）和Seyfert 1星系的B波段成像数据的分析，与其他光学巡天相比，与主星系相关的选择偏差大大减少。样本中只有一个物体已知具有无线电响度。我们采用了一种程序，通过从每个 QSO 图像中减去缩放的点扩散函数来消除活动星系核 (AGN) 的贡献。为了回收综合的宿主星系通量，我们根据模拟校正了过度减法。这种方法对宿主星系的形态类型相当不敏感，我们可以明确地为 57 个天体中的 15 个建立该形态类型。在所有情况下都检测到类星体宿主星系。宿主非常明亮，绝对星等MB从−19.0到−23.8不等，平均MB,gal =− 21.5，远高于场星系的L*。对于 MB < −23 的发光 QSO 子样本，平均宿主绝对星等为 MB,gal =− 23.0，而对于互补的低光度 AGN，我们获得 MB,gal =− 21.2，大致等于 L * 。当从较长波段的类似天体研究中推断 B 波段光度时，样本中的发光宿主星系通常比预期亮约 1 星等。我们认为这种不匹配不太可能用选择效应来解释，但有利于宿主星系的颜色比不活跃星系的颜色明显更蓝。尽管发表的 B 波段数据很少，但这一结果与其他作者的发现非常一致。
We report on the analysis of B-band imaging data of 57 low-redshift quasi-stellar objects (quasars/QSOs) and Seyfert 1 galaxies selected from the Hamburg/ESO Survey, for which hostgalaxy-dependent selection biases are greatly reduced compared with other optical surveys. Only one object in the sample is known to be radio-loud. We adopted a procedure to remove the active galactic nuclei (AGN) contribution by subtracting a scaled point spread function from each QSO image. To reclaim the integrated host galaxy flux we correct for oversubtraction based on simulations. This method is quite insensitive to the host galaxy morphological type, which we can unambiguously establish for 15 of the 57 objects. The quasar host galaxies are detected in all cases. The hosts are very luminous, ranging in absolute magnitude MB from −19.0 to −23.8, with an average of M B,gal =− 21.5, considerably above L ∗ for field galaxies. For the luminous QSO subsample with MB < −23 the average host absolute magnitude is M B,gal =− 23.0, while for the complementary low-luminosity AGN we obtain M B,gal =− 21.2, roughly equal to L ∗ . The luminous host galaxies in the sample are typically ∼1 mag brighter than expected when inferring B-band luminosities from studies of similar objects at longer wavebands. We argue that this mismatch is not likely to be explained by selection effects, but favours host galaxy colours significantly bluer than those of inactive galaxies. Although published B-band data are scant, this result and the findings of other authors are in good agreement.