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arXiv 2005.09911astro-ph.GA
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用LAMOST和SDSS表征某些Gaia警报

Characterizing Some Gaia Alerts with LAMOST and SDSS

Z. Huo, M. Dennefeld, X. Liu, T. Pursimo, T. Zhang

备注：
Accepted for publication in APSS, 14 pages, 8 figures, 2 tables
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摘要：

盖亚定期对检测到光度变化的物体发出警报。这些物体的物理性质往往需要借助地面设施的补充观测来确定。我们将盖亚警报列表（直到2018年1101）与LAMOST和SDSS光谱数据进行了比较。地面观测的日期很少与警报的日期相对应，但这至少可以识别源，如果它是持久的，或者如果物体只是像超新星一样短暂，则可以识别宿主星系。来自Kostrzewa-Rutkowska等人（2018）的盖亚核瞬变列表也包含在本次检索中。我们在LAMOST+SDSS中发现了26个Gaia警报，其光谱被标记为恒星（12个具有多历元光谱）。大多数都是CV。类似地，206个盖亚警报具有标记为星系的相关光谱（49个具有多历元光谱）。这些光谱通常是在与警戒日期不同的日期获得的，大多数是发射线星系，导致怀疑大多数警戒是由于SN。至于GNT列表，我们发现了55个标记为星系的相关光谱（13个具有多历元光谱）。在两个星系Gaia 17 aal和GNTJ 170213 +2543中，光谱观测的日期足够接近警报日期：我们在它们的LAMOST光谱中发现了SN本身的痕迹，这两个星系都被归类为Ia型SN。GNT样本中活动星系核的比例更高，这表明一些检测到的变化也是由于活动星系核本身。类似的类星体，我们发现了30个盖亚警报，但68个GNT案例有单历元类星体光谱，而12加23有多历元光谱。对于这35个中的10个，它们的多历元光谱显示了宽巴耳末线的出现或消失，以及连续谱的变化，将它们定性为“变化外观类星体”。

英文摘要：

Gaia is regularly producing Alerts on objects where photometric variability has been detected. The physical nature of these objects has often to be determined with the complementary observations from ground-based facilities. We have compared the list of Gaia Alerts (until 20181101) with archival LAMOST and SDSS spectroscopic data. The date of the ground-based observation rarely corresponds to the date of the Alert, but this allows at least the identification of the source if it is persistent, or the host galaxy if the object was only transient like a supernova. A list of Gaia Nuclear Transients from Kostrzewa-Rutkowska et al. (2018) has been included in this search also. We found 26 Gaia Alerts with spectra in LAMOST+SDSS labelled as stars (12 with multi-epoch spectra). A majority of them are CVs. Similarly 206 Gaia Alerts have associated spectra labelled as galaxies (49 with multi-epoch spectra). Those spectra were generally obtained on a date different from the Alert date, are mostly emission-line galaxies, leading to the suspicion that most of the Alerts were due to a SN. As for the GNT list, we found 55 associated spectra labelled as galaxies (13 with multi-epoch spectra). In two galaxies, Gaia17aal and GNTJ170213+2543, was the date of the spectroscopic observation close enough to the Alert date: we find a trace of the SN itself in their LAMOST spectrum, both classified here as a type Ia SN. The GNT sample has a higher proportion of AGNs, suggesting that some of the detected variations are also due to the AGN itself. Similar for Quasars, we found 30 Gaia Alerts but 68 GNT cases have single epoch quasar spectra, while 12 plus 23 have multi-epoch spectra. For ten out of these 35, their multi-epoch spectra show appearance or disappearance of the broad Balmer lines and also variations in the continuum, qualifying them as "Changing Look Quasars".

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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