Ultracompact binaries: Gravitational wave sources and supernova Ia progenitors

超紧凑双星（UCB）由一对非常接近的白色矮星（WD），中子星星（NS）和/或氦星组成，研究是更好地理解后期双星星星演化以及Ia型超新星（SN）替代路径的关键，后者代表了我们确定银河系外距离尺度和宇宙最终命运的最佳“标准烛光”（例如，宇宙加速）。银河系的UCB也将被下一代重力波望远镜如欧空局/美国宇航局的激光干涉仪空间天线（丽莎）定期探测。德克萨斯理工大学的一个研究小组将分析两个半球银河平面的快速节奏调查，以确定数百个新UCB的统一样本。这项研究将支持一个博士学位。候选人主要研究人员还将建立一个项目，将研究经验带给服务不足和农村的小学，初中和高中学生，并进行教师培训。UCB可以通过它们的光变曲线来检测，它显示了由于日食或潮汐变形而导致的短至30分钟的时间尺度变化。NSF资助的Zwicky Transient Facility（ZTF）和BlackGEM阵列是覆盖两个半球的下一代光学时域调查。这项研究将联合收割机的数据与其他大规模的调查，如eROSITA，PanSTARRS，盖亚和SDSS-V编译银河系平面UCB的统一样本。该项目预计将发现和表征几百个新的UCB，并预计为几十个系统确定准确的系统参数。大样本将用于挑战常见的包络和二元进化理论（例如，预测与观测到的轨道周期和组件质量分布），并计算各种途径的经验SNIa率。他们希望将已知的LISA可检测源的数量增加两倍，并将已知的SN Ia祖细胞的数量增加至少一个数量级。UCB预计将主导丽莎可探测的源，因此将产生随机的前景引力波信号。在短期内，描述银河系UCB群的特征对于为丽莎找到最佳设计和数据分析方法以自信地探测其他引力波源（例如，双星黑洞或白色矮星合并）隐藏在这种“噪音”中。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Studies of Ultra-compact binaries (UCBs), consisting of an extremely close pair of white dwarf (WD), neutron star (NS), and/or helium stars, are key to a better understanding of late-stage binary star evolution as well as alternate pathways to Type Ia supernovae (SN), the latter representing our best "standard candle" for determining the extra-galactic distance scale and the ultimate fate of the universe (e.g., cosmic acceleration). Galactic UCBs will also be routinely detected by the next generation of gravity wave telescopes like ESA/NASA's Laser Interferometer Space Antenna (LISA). A research team at Texas Tech University will analyze a fast cadence survey of the Galactic Plane in both hemispheres to identify a uniform sample of several-hundred new UCBs. The research will support a Ph.D. candidate. The principal investigator will also establish a program to bring research experience to underserved and rural elementary, middle, and high-school students plus teacher-training.UCBs can be detected through their light-curves, which show variations on timescales as short as 30-min due to eclipses or tidal deformation of the close components. The NSF-funded Zwicky Transient Facility (ZTF) and the BlackGEM array are the next generation optical time-domain surveys covering both hemispheres. This research will combine data from both with other large-scale surveys, such as eROSITA, PanSTARRS, Gaia, and SDSS-V to compile a uniform sample of Galactic plane UCBs. This project expects to find and characterize a few hundred new UCBs and anticipates the determination of accurate system parameter for a few tens of systems. The large sample will be used to challenge common envelope and binary evolution theories (e.g., predicted vs. observed orbital period and component mass distributions) and calculate empirical SN Ia rates for various pathways. They expect to triple the number of known LISA-detectable sources and increase the number of known SN Ia progenitors by at least an order of magnitude. UCBs are expected to dominate the sources detectable by LISA and will thus create a stochastic foreground gravitational wave signal. Characterizing the Galactic UCB population will be important in the near term for finding optimal design and data analysis methods for LISA to confidently detect other gravitational wave sources (e.g., binary blackhole or white dwarf mergers) hidden in this “noise”. This project thus advances the goals of the NSF Windows on the Universe Big Idea.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.