Distances to star-forming regions using Gaia-DR2 parallaxes: the case of W3 complex in the Perseus Arm

27/11/2019 - 14:00 - 15:00
Auditório "Prof. Dr. Paulo Benevides Soares", Bloco G

Distances to star-forming regions using Gaia-DR2 parallaxes: the case of W3 complex in the Perseus Arm


Felipe Navarete



The Perseus Arm is the closest Galactic spiral arm from the Sun, offering an excellent opportunity to study in detail its structure. The complex of HII regions W3 is located within the Perseus arm in the Galactic anti-center direction. So far, the distance to the W3 complex has been controversial with discrepancies by a factor of two, reinforcing previous claims that this arm exhibits peculiar velocities: kinematic distances are in the range of 3.9-4.2 kpc while spectrophotometric and trigonometric parallaxes lead to distances of 1.9-2.3 kpc. Thanks to the second Gaia data release (Gaia-DR2), distances to star-forming regions within the Perseus Arm and beyond (> 2 kpc) can now be evaluated using trigonometric parallaxes.

In this seminar, I will present the evaluation of the distance to the W3 complex and its main sub-structures using the Gaia-DR2 astrometric information, and I comment on the Gaia-DR2 limitations to investigate regions at such large distances. I will also present some preliminary results using Principal Component Analysis on Gaia-DR2 astrometry to infer the distance of other regions, such as the massive stellar cluster Westerlund 1.