Search Publications
A Spatially Dependent Correction of Gaia EDR3 Parallax Zero-point Offset based on 0.3 million LAMOST DR8 Giant Stars
Huang, Yang; Yuan, Haibo; Wang, Chun
We have studied the zero-point offset of Gaia Early Data Release 3 (EDR3) parallaxes based on a sample of 0.3 million giant stars built from the LAMOST data with distance accuracy better than 8.5%. The official parallax zero-point corrections largely reduce the global offset in the Gaia EDR3 parallaxes: the global parallax offsets are -27.9 µ…
MICROSCOPE mission: statistics and impact of glitches on the test of the weak equivalence principle
Bergé, Joel; Métris, Gilles; Rodrigues, Manuel +6 more
MICROSCOPE's space test of the weak equivalence principle (WEP) is based on the minute measurement of the difference of accelerations experienced by two test masses as they orbit the Earth. A detection of a violation of the WEP would appear at a well-known frequency f EP depending on the satellite's orbital and spinning frequencies. Con…
A method for identifying metal-poor stars with Gaia BP/RP spectra
Lind, K.; Xylakis-Dornbusch, T.; Christlieb, N. +1 more
Context. The study of the oldest and most metal-poor stars in our Galaxy promotes our understanding of the Galactic chemical evolution and the beginning of Galaxy and star formation. However, they are notoriously difficult to find, with only seven stars at [Fe/H] < −5.0 having been detected to date. Thus, the spectrophotometric data of 219 mill…
Detection of 7Be II in the Small Magellanic Cloud
Izzo, Luca; Selvelli, Pierluigi; Della Valle, Massimo +8 more
We analyse high-resolution spectra of two classical novae that exploded in the Small Magellanic Cloud (SMC). 7Be II resonance transitions are detected in both ASASSN-19qv and ASASSN-20ni novae. This is the first detection outside the Galaxy and confirms that thermo-nuclear runaway reactions, leading to the 7Be formation, are …
Connecting Low- and High-redshift Weak Emission-line Quasars via Hubble Space Telescope Spectroscopy of Lyα Emission
Brandt, W. N.; Anderson, Scott F.; Fan, Xiaohui +10 more
We present ultraviolet spectroscopy covering the Lyα + N V complex of six candidate low-redshift (0.9 < z < 1.5) weak emission-line quasars (WLQs) based on observations with the Hubble Space Telescope. The original systematic searches for these puzzling Type 1 quasars with intrinsically weak broad emission lines revealed an N ≈ 100 WLQ popul…
Identifying the population of stable ν6 resonant asteroids using large data bases
Carruba, V.; Aljbaae, S.; Domingos, R. C. +2 more
Large observational surveys, like those that will be conducted at the Vera C. Rubin Observatory, are expected to discover up to one million new asteroids in the first year of operation. This will more than double the data base of known asteroids. New methods will be needed to handle the large influx of data. Here, we tested some of these new appro…
SKYSURF-3: Testing Crowded Object Catalogs in the Hubble eXtreme Deep Field Mosaics to Study Sample Incompleteness from an Extragalactic Background Light Perspective
Pirzkal, Nor; Windhorst, Rogier A.; Koekemoer, Anton +6 more
Extragalactic background light (EBL) studies have revealed a significant discrepancy between direct measurements-via instruments measuring "bare" sky from which Zodiacal and Galactic light models are subtracted-and measurements of the integrated galaxy light (IGL). This discrepancy could lie in either method, whether it be an incomplete Zodiacal m…
Dust grain size evolution in local galaxies: a comparison between observations and simulations
Saintonge, A.; De Looze, I.; Smith, M. W. L. +13 more
The evolution of the dust grain size distribution has been studied in recent years with great detail in cosmological hydrodynamical simulations taking into account all the channels under which dust evolves in the interstellar medium. We present a systematic analysis of the observed spectral energy distribution of a large sample of galaxies in the …
A Star-sized Impact-produced Dust Clump in the Terrestrial Zone of the HD 166191 System
Rieke, G. H.; Kennedy, Grant M.; Su, Kate Y. L. +2 more
We report on five years of 3-5 µm photometry measurements obtained by warm Spitzer to track the dust debris emission in the terrestrial zone of HD 166191 in combination with simultaneous optical data. We show that the debris production in this young (~10 Myr) system increased significantly in early 2018 and reached a record high level (almos…
Long-term photometric monitoring and spectroscopy of the white dwarf pulsar AR Scorpii
Dhillon, V. S.; Pelisoli, Ingrid; Breedt, E. +14 more
AR Scorpii (AR Sco) is the only radio-pulsing white dwarf known to date. It shows a broad-band spectrum extending from radio to X-rays whose luminosity cannot be explained by thermal emission from the system components alone, and is instead explained through synchrotron emission powered by the spin-down of the white dwarf. We analysed NTT/ULTRACAM…