Classical Cepheids (DCEPs) are potentially excellent tracers of the young stellar population that is responsible for shaping the visible aspect of our Galaxy, the Milky Way. We estimate new distances for 3427 Cepheids based on mid-IR photometry from WISE, which suffers minimally from extinction, and by adopting a 3D extinction map to calculate the necessary (albeit small) extinction corrections.
We show that our distances are consistent with Gaia’s parallaxes for the subset with relative parallax errors smaller than 10%, verifying that our mean distance errors are less than 15% and that the mean parallax zeropoint for this sample is about 7 microarcseconds in magnitude.
We use the new distances for a subset of dynamically young DCEPs to trace the spiral arms of the Milky Way, deriving pitch angles for four spiral arms: the Perseus, Local (Orion), Sagittarius-Carina and Scutum arms.
These arms are traced by the DCEPS well into the third and fourth galactic quadrants where there is currently a lack of masers with astrometric parallaxes, thus significantly extending our picture of the spiral structure of our Milky Way on large-scales.
11/07/2024
Speaker: Ronald Drimmel (INAF-OATo)
Link for the streaming: https://meet.google.com/dnn-zdwd-anj
11 July at 11 CEST