Lunck talk on Nov. 29, 2019
The Period-Luminosity Relations of Red Supergiants in the Local Group Galaxies
Speaker: Yi Ren (BNU)
Venue: Room 2111, SWIFAR Building
Time: 12:30 PM, Friday, November 29, 2019
According to the infrared luminosity and colors from the 2MASS, Spitzer and WISE observations as well as the Gaia parallax measurement, the as-complete-as-possible samples of red supergiants (RSGs) are selected in the SMC, LMC, M33 and M31. Based on the time-domain data from the iPTF and ASAS surveys, the light variations of these RSGs are analyzed. For the semi-regular variables, the P-L relations are derived for the optical to infrared bands. It is found that the P-L relations are very tight in the infrared bands and the P-Mk relation shows little dependence on the metallicity of the galaxy. Meanwhile whether the pulsation is on the fundamental or first overtone mode seems depending on the metallicity, the reasons for which are discussed.