A RESONANT FEATURE NEAR THE PERSEUS ARM REVEALED BY RED CLUMP STARS
- Key Laboratory of Optical Astronomy, National Astronomical Observatories, CAS, 20A Datun Road, Chaoyang District, 100012 Beijing (China)
- Purple Mountain Observatory and Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, 2 West Beijing Road, 210008 Nanjing (China)
- Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)
We investigate the extinction, together with the radial velocity (RV) dispersion and distribution of red clump stars in the anticenter direction using spectra obtained with Hectospec on the MMT. We find that extinction peaks at Galactocentric radii of about 9.5 and 12.5 kpc, right in front of the locations of the Perseus and Outer arms and in line with the relative position of dust and stars in external spiral galaxies. The RV dispersion peaks around 10 kpc, which coincides with the location of the Perseus arm, yields an estimated arm-interarm density contrast of 1.3-1.5, and is in agreement with previous studies. Finally, we discover that the RV distribution bifurcates around 10-11 kpc into two peaks at +27 km s{sup -1} and -4 km s{sup -1}. This seems to be naturally explained by the presence of the outer Lindblad resonance of the Galactic bar, but further observations will be needed to understand if the corotation resonance of the spirals arms also plays a role.
- OSTI ID:
- 22047699
- Journal Information:
- Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 753; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
PARALLAXES FOR W49N AND G048.60+0.02: DISTANT STAR FORMING REGIONS IN THE PERSEUS SPIRAL ARM
Radial Velocities in the Outermost Disk toward the Anticenter