학술논문
Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event
Document Type
Working Paper
Author
Zang, Weicheng; Dong, Subo; Gould, Andrew; Novati, Sebastiano Calchi; Chen, Ping; Yang, Hongjing; Li, Shun-Sheng; Mao, Shude; Alton, K. B.; Carey, Sean; Christie, G. W.; Delplancke-Ströbele, F.; Feliz, Dax L.; Green, J.; Hu, Shaoming; Jayasinghe, T.; Koff, R. A.; Kurtenkov, A.; Mérand, A.; Minev, Milen; Mutel, Robert; Natusch, T.; Roth, Tyler; Shvartzvald, Yossi; Sun, Fengwu; Vanmunster, T.; Zhu, Wei
Source
Subject
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Abstract
We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555. We measure the microlens parallax vector ${\pi}_{\rm E}$ using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interferometer (VLTI) GRAVITY observations. Combining this ${\pi}_{\rm E}$ determination with the angular Einstein radius $\theta_{\rm E}$ measured by VLTI GRAVITY observations, we find that the lens is a star with mass $M_{\rm L} = 0.495 \pm 0.063~M_{\odot}$ at a distance $D_{\rm L} = 429 \pm 21~{\rm pc}$. We find that the blended light basically all comes from the lens. The lens-source proper motion is $\mu_{\rm rel,hel} = 26.55 \pm 0.36~{\rm mas\,yr^{-1}}$, so with currently available adaptive-optics (AO) instruments, the lens and source can be resolved in 2021. This is the first microlensing event whose lens mass is unambiguously measured by interferometry + satellite parallax observations, which opens a new window for mass measurements of isolated objects such as stellar-mass black holes.
Comment: 3 Figures and 6 Tables Submitted to AAS Journal
Comment: 3 Figures and 6 Tables Submitted to AAS Journal