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SAC Seminar - Govind NandakumarGalactic archaeology and its application to the Galactic centre region

01.02.2018 | Louise Børsen-Koch

Dato fre 02 feb
Tid 11:15 12:00
Sted 1520-616

With ongoing and upcoming large Galactic archaeology spectroscopic surveys such as APOGEE, RAVE, LAMOST, GALAH etc, it is essential to know the specific selection function which is related to the targeting strategy of each of them. By using common fields along similar lines of sight between APOGEE, LAMOST, GES and RAVE, and together with stellar population synthesis models, I investigate the selection function effect on the metallicity distribution function (MDF) and the vertical metallicitiy gradients in the solar neighbourhood. My results indicate that there is negligible selection function effect on the MDF and the vertical metallicity gradients. These results suggest that different spectroscopic surveys (different resolutions and wavelength range) can be combined for such studies provided their metallicities are put on the same scale. 

A major challenge in the chemical evolution models is the lack of knowledge about the star formation history and the star formation rate in the Milky Way. The inner 200 pc of the Milky way, the so called central molecular zone (CMZ), has a large reservoir of molecular gas with the evidence of star formation activity during the last 100,000 years. I used low resolution KMOS spectra (VLT) to identify and analyse massive young stellar objects (YSOs) and estimated the star formation rate in the CMZ. 

While more and more spectroscopic observations of the outer bulge regions reveal the complex structure of the Milky Way bulge, there is a lack of detailed chemical abundances studies in the inner bulge region (400-500 pc). I will present high resolution K-band spectra of K/M giants obtained using the high resolution infrared spectrograph, CRIRES (R-50,000), on VLT in this highly obscured region. I will discuss the MDF and detailed chemical abundances of our sample in this region as well as the North-South symmetry in MDF along the bulge minor axis.