5 papers
TwinSpecNet: Extending APOGEE's chemical reach to low-S/N spectra via empirical paired learning
Weijia Sun, Cristina Chiappini, Samir Nepal
Large spectroscopic surveys rely on automated pipelines to deliver homogeneous stellar labels, but a substantial fraction of observations are at low signal-to-noise ratio (S/N), wh…
The oldest Milky Way stars: New constraints on the age of the Universe and the Hubble constant
Elena Tomasetti, Cristina Chiappini, Samir Nepal +6
We exploit the most robust, old, and cosmology-independent age estimates of individual stars from Gaia DR3 to place a lower bound on the age of the Universe, . These constrain…
The Nineteenth Data Release of the Sloan Digital Sky Survey
SDSS Collaboration, Gautham Adamane Pallathadka, Mojgan Aghakhanloo +209
Mapping the local and distant Universe is key to our understanding of it. For decades, the Sloan Digital Sky Survey (SDSS) has made a concerted effort to map millions of celestial…
The Spheroidal Bulge of the Milky Way: Chemodynamically Distinct from the Inner-Thick Disc and Bar
Samir Nepal, Cristina Chiappini, Angeles Pérez-Villegas +7
Studying the composition and origin of the inner region of our Galaxy -- the "Galactic bulge" -- is crucial for understanding the formation and evolution of the Milky Way and other…
Insights from Super-Metal-Rich Stars: Is the Milky Way bar young?
Samir Nepal, Cristina Chiappini, Guillaume Guiglion +6
Super-metal-rich (SMR) stars, currently in the solar neighbourhood, are expected to originate only in the inner Galaxy and have definitely migrated. We aim at studying a large samp…