From its inception, the Spiders ERC project made substantial strides across three main areas: characterising the spider system population, discovering new spider systems, and advancing theoretical understanding of these systems.
1. Characterisation:
- Observations: Follow-up observations using world-class optical telescopes characterised spider binaries.
- Extreme Systems: Identified some of the most extreme pulsars, including the second-fastest spinning neutron star.
- Long-term Variability: Investigated long-term optical variability in spider binary light curves, linking these changes to the evolution between accreting X-ray binaries and radio pulsar binaries.
2. Discovery:
- Multi-wavelength Synergy: Developed a method using optical observations to constrain parameters for gamma-ray and radio pulsation searches, leading to the discovery of two new spider systems.
- Large Surveys: Expanded the method to a large radio survey as part of MeerKAT's TRAPUM project, leading to the discovery of over 40 new pulsars, including around 15 new spider systems. Conducted optical surveys using the Thai Robotic Telescope network, NTT with ULTRACAM, GOTO, and BlackGEM to provide input for radio surveys.
3. Theoretical Understanding:
- Modeling Improvements: Improved the modelling of spider timing data by incorporating tides and general relativity effects, predicting non-circular orbits and providing insights into the internal structure of companion stars.
- Gravitational Quadrupole Moment: Detected the gravitational quadrupole moment of companion stars in spider systems, allowing researchers to probe the internal distribution of matter within these stars and understand stellar evolution.
Key Work Packages and Results:
- High-Precision Physics and Equation of State: Obtained high-precision photometry and spectroscopy data, leading to several key publications. Although an overly massive neutron star remains unproven, measurements delineated the landscape of neutron star masses and contributed to significant methodological advancements.
- Innovative Searching and Monitoring: Conducted a large optical survey using the ULTRACAM instrument, discovering multiple new spider pulsars. Joined consortia like BlackGEM and GOTO, monitoring spider binaries for state transitions and contributing to publications beyond the project's initial scope.
- Impact on Spider Binaries' Environment: Research on evaporation mechanisms and binary evolution refined our understanding of these processes. Developed foundational models for heat redistribution in irradiated binaries, with limited but ongoing efforts to detect circumbinary dust emissions.
- Discovery of Gamma Ray Eclipses: Analysed Fermi gamma ray data, discovering gamma ray eclipses in several systems. These eclipses provide direct geometrical constraints on orbits and companion sizes, validating optical modeling measurements.
Overall, the Spiders ERC project achieved significant progress, with numerous publications and discoveries advancing our understanding of neutron stars. The project's innovative approaches and comprehensive analysis promise continued advancements in high energy physics and stellar evolution.
