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تسجيل مستخدم جديدSpitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event
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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.
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