标题： 从IGAPS-GALEX交叉匹配中挑选的热白矮星候选体 显示英文标题

标题： Hot white dwarf candidates from the IGAPS-GALEX cross-match

摘要： 白矮星（WD）恒星通常与行星状星云的中心星（CSPNe）相关联，这些中心星正走向冷却轨迹。 由于光学巡天数据（如盖亚DR2和EDR3）的帮助，已经识别出大量WD恒星候选体。 然而，由于高温和低光学亮度，热WD/CSPNe在光学波段非常难以观测到。 星系演化探测器（GALEX）与国际巡视巡天（IGAPS）的匹配使我们能够通过结合GALEX远紫外（FUV）和近紫外（NUV）以及光学测光波段（g, r, i 和 H$\alpha$）来识别热WD候选体。 在排除了源混淆并过滤掉不良的测光数据后，在GALEX和IGAPS的覆盖范围内（称为GaPHAS）共发现了236485个源。 使用GALEX颜色切割FUV-NUV>-0.53初步选择了热恒星源，得到了74个热WD候选体。 我们利用MCMC算法开发了一个用于单体和双体谱能量分布（SED）拟合的程序来分析它们的SED；估计约有41个可能是双星系统（双星比例约为55%）。 此外，我们使用样本中的不同红外（IR）颜色分类WD恒星候选体，得到了与SED分析中单星和双星系统类似的结果。 这支持了拟合方法的可靠性以及GALEX紫外光与光学测光相结合的优势。 为了确认WD恒星候选体的性质，需要地面时序测光和光谱观测。 显示英文摘要

摘要： White dwarf (WD) stars are often associated with the central stars of planetary nebulae (CSPNe) on their way to the cooling track. A large number of WD star candidates have been identified thanks to optical large-scale surveys such as Gaia DR2 and EDR3. However, hot-WD/CSPNe stars are quite elusive in optical bands due to their high temperatures and low optical luminosities. The Galaxy Evolution Explorer (GALEX) matched with the INT Galactic Plane Survey (IGAPS) allowed us to identify hot-WD candidates by combining the GALEX far-UV (FUV) and near-UV (NUV) with optical photometric bands (g, r, i and H$\alpha$). After accounting for source confusion and filtering bad photometric data, a total of 236485 sources were found in the GALEX and IGAPS footprint (GaPHAS). A preliminary selection of hot stellar sources was made using the GALEX colour cut on FUV-NUV>-0.53, yielding 74 hot-WD candidates. We analysed their spectral energy distribution (SED) by developing a fitting program for single- and two-body SED using an MCMC algorithm; 41 are probably binary systems (a binary fraction of ~55% was estimated). Additionally, we classified the WD star candidates using different infrared (IR) colours available for our sample obtaining similar results as in the SED analysis for the single and binary systems. This supports the strength of the fitting method and the advantages of the combination of GALEX UV with optical photometry. Ground-based time-series photometry and spectra are required in order to confirm the nature of the WD star candidates.