We independently determine the zero-point offset of the Gaia early Data Release-3 (EDR3) parallaxes based on ∼110,000 W Ursae Majoris (EW)-type eclipsing binary systems. EWs cover almost the entire sky and are characterized by a relatively complete coverage in magnitude and color. They are an excellent proxy for Galactic main-sequence stars. We derive a W1-band period–luminosity relation with a distance accuracy of 7.4%, which we use to anchor the Gaia parallax zero-point. The final, global parallax offsets are −28.6 0.6 μas and −25.4 4.0 μas (before correction) and 4.2 0.5 μas and 4.6 3.7 μas (after correction) for the five- and six-parameter solutions, respectively. The total systematic uncertainty is 1.8 μas. The spatial distribution of the parallax offsets shows that the bias in the corrected Gaia EDR3 parallaxes is less than 10 μas across 40% of the sky. Only 15% of the sky is characterized by a parallax offset greater than 30 μas. Thus, we have provided independent evidence that the parallax zero-point correction provided by the Gaia team significantly reduces the prevailing bias. Combined with literature data, we find that the overall Gaia EDR3 parallax offsets for Galactic stars are [−20, −30] μas and 4–10 μas, respectively, before and after correction. For specific regions, an additional deviation of about 10 μas is found.

我们基于~110,000 W Ursae Majoris (EW) 型食双星系统独立确定了 Gaia 早期数据版本 3 (EDR3) 视差的零点偏移。电子战几乎覆盖了整个天空，其特点是在震级和颜色上覆盖相对完整。它们是银河系主序星的绝佳代表。我们推导出距离精度为 7.4% 的 W1 波段周期-亮度关系，我们用它来锚定 Gaia 视差零点。对于五参数和六参数解，最终的全局视差偏移分别为 -28.6 0.6 μ as 和 -25.4 4.0 μ as（校正前）和 4.2 0.5 μ as 和 4.6 3.7 μ as（校正后）。总系统不确定度为 1.8 μ作为。视差偏移的空间分布表明，在 40% 的天空中，校正后的 Gaia EDR3 视差中的偏差小于 10 μ。只有 15% 的天空具有大于 30 μ as的视差偏移。因此，我们提供了独立的证据，证明 Gaia 团队提供的视差零点校正显着降低了普遍存在的偏差。结合文献数据，我们发现校正前后银河系恒星整体的Gaia EDR3视差偏移分别为[-20,-30] μ as和4-10 μ as。对于特定区域，发现了大约 10 μ的附加偏差。