论文标题
Galaxy NGC 7793中的候选LBV星通过HST光度法 + MUSE Spectroscoppoy
Candidate LBV stars in galaxy NGC 7793 found via HST photometry + MUSE spectroscopy
论文作者
论文摘要
迄今为止，只有大约19个银河系和25次半乳酸善良的发光蓝色变量（LBV）。这种不完整的人口普查阻止了我们对巨大恒星进化的这一关键阶段的理解，从而导致通过经典通道形成重型二元黑洞。使用大量LBV样品，可以更好地确定该阶段的持续时间和最大恒星光度。我们在新的Galaxy，NGC 7793中搜索候选LBVS（CLBV）。为此，我们将来自两个Hubble Space望远镜（HST）程序的高空间分辨率图像与来自Multi单元光谱探索器（博物馆）的光谱相结合。通过结合在F547M，F657N和F814W图像上测量的PSF拟合光度法，并与点样外观（HST分辨率）和Hα光度限制，我们发现100个潜在的CLBV，其中36个属于缪斯群领域。后36个来源中有五个是有希望的CLBV，其M（V）小于或等于-7，并且组合：Hα具有P -Cygni曲线；没有[O I] 6300排放；弱或没有[O III] 5007排放；相对于H II区域的大[N II]/Hα； [S II] 6716 / [S II] 6731与1相似。目前尚不清楚这五个CLBV是否是从O型恒星中分离出来的，这将有利于LBV的二进制形成场景。我们的研究大约涵盖了NGC 7793的光盘的四分之一，它表明了如何通过将上述HST调查与8-M类望远镜的多对象光谱相结合，人们可以在附近的星系中有效地找到大型CLBVS样本。
Only about 19 Galactic and 25 extra-galactic bona-fide Luminous Blue Variables (LBVs) are known to date. This incomplete census prevents our understanding of this crucial phase of massive star evolution which leads to the formation of heavy binary black holes via the classical channel. With large samples of LBVs one could better determine the duration and maximum stellar luminosity which characterize this phase. We search for candidate LBVs (cLBVs) in a new galaxy, NGC 7793. For this purpose, we combine high spatial resolution images from two Hubble Space Telescope (HST) programs with optical spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE). By combining PSF-fitting photometry measured on F547M, F657N, and F814W images, with restrictions on point-like appearance (at HST resolution) and Hα luminosity, we find 100 potential cLBVs, 36 of which fall in the MUSE fields. Five of the latter 36 sources are promising cLBVs which have M(V) less than or equal to -7 and a combination of: Hα with a P-Cygni profile; no [O I] 6300 emission; weak or no [O III] 5007 emission; large [N II]/Hα relative to H II regions; and [S II] 6716 / [S II] 6731 similar to 1. It is not clear if these five cLBVs are isolated from O-type stars, which would favor the binary formation scenario of LBVs. Our study, which approximately covers one fourth of the optical disc of NGC 7793, demonstrates how by combining the above HST surveys with multi-object spectroscopy from 8-m class telescopes, one can efficiently find large samples of cLBVs in nearby galaxies.
