A spectroscopic follow-up for Gaia19bld
arXiv:2112.01676 · doi:10.1051/0004-6361/202039548
Abstract
Due to their scarcity, microlensing events in the Galactic disk are of great interest and high-cadence photometric observations, supplemented by spectroscopic follow-up, are necessary for constraining the physical parameters of the lensing system. In particular, a precise estimate of the source characteristics is required to accurately measure the lens distance and mass. We conducted a spectroscopic follow-up of microlensing event Gaia19bld to derive the properties of the microlensing source and, ultimately, to estimate the mass and distance of the lens. We obtained low- and high-resolution spectroscopy from multiple sites around the world during the course of the event. The spectral lines and template matching analysis has led to two independent, consistent characterizations of the source. We found that the source is a red giant located at about 8.5 kpc from the Earth. Combining our results with the photometric analysis has led to a lens mass of Ml=1.1 M at a distance of D l = 5.5 kpc. We did not find any significant blend light in the spectra (with an upper detection limit of V < 17 mag), which is in agreement with photometric observations. Therefore, we cannot exclude the possibility that the lens is a main-sequence star. Indeed, we predict in this scenario a lens brightness of V about 20 mag, a value that would make it much fainter than the detection limit.
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References in corpus (14)
- The Gaia mission
- A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
- K-corrections and filter transformations in the ultraviolet, optical, and near infrared
- Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
- Modern stellar spectroscopy caveats
- CERES: A Set of Automated Routines for Echelle Spectra
- Spitzer as Microlens Parallax Satellite: Mass Measurement for the OGLE-2014-BLG-0124L Planet and its Host Star
- Flux calibration of medium-resolution spectra from 300 nm to 2500 nm: Model reference spectra and telluric correction
- Predicting Stellar Angular Diameters from , , , Photometry
- A Search for Stellar-Mass Black Holes via Astrometric Microlensing
- Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star
- Near-Field Microlensing from Wide-Field Surveys
- Single-lens mass measurement in the high-magnification microlensing event Gaia19bld located in the Galactic disc
- Spectroscopic characterisation of microlensing events Towards a new interpretation of OGLE-2011-BLG-0417