New classical Cepheids in the inner part of the northern Galactic disk and their kinematics

TL;DR

This study identifies new classical Cepheids in the dust-obscured inner Galactic disk using infrared surveys, providing insights into their distances, ages, and kinematics near the Galactic bar.

Contribution

It reports the discovery of three new Cepheids in the inner Galaxy and analyzes their velocities, contributing to understanding Galactic structure and dynamics.

Findings

One Cepheid's velocity aligns with Galactic rotation.

Two Cepheids move significantly slower than expected.

Their kinematics differ from high-mass star-forming regions.

Abstract

The characteristics of the inner Galaxy remain obscured by significant dust extinction, and hence infrared surveys are useful to find young Cepheids whose distances and ages can be accurately determined. A near-infrared photometric and spectroscopic survey was carried out and three classical Cepheids were unveiled in the inner disk, around 20 and 30 degrees in Galactic longitude. The targets feature small Galactocentric distances, 3-5 kpc, and their velocities are important as they may be under the environmental influence of the Galactic bar. While one of the Cepheids has radial velocity consistent with the Galactic rotation, the other two are moving significantly slower. We also compare their kinematics with that of high-mass star-forming regions with parallactic distances measured.