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Public Seminar of RPg Student:
Planetary nebulae in the Galactic bulge


Speaker:Ms. Shuyu TAN
Affiliation:The University of Hong Kong
Date:June 15, 2021 (Tuesday)
Time:4:30 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract
 

Planetary Nebulae (PNe) are layers of gas and dust shrouding dying stars with low- and intermediate-masses, showing strong emission lines. The spectra and characteristics of PNe provide us with a powerful probe to the evolution history, mass-loss physics, and chemical abundances of their progenitors. With the advancement of wide-field and high-accuracy telescopes, for example, the HST and the ESO VLT, both high-resolution images and long-slit spectra are available for a growing number of PNe. This allows an improvement in our understanding of both the dynamical processes in PN formation, furthermore, analyse the chemical abundance which may give insight into the chemical evolution of the galaxy.

The main purpose of this project is to make full use of the observation of 104 PNe in the Galactic bulge using the ESO VLT. The set of observational data is comprised of highly detailed images and long-slit spectroscopy with both red and blue prisms, covering a wavelength range from 3660 to 8450 Å. This study first obtained information on mythologies and positions of PNe as well as the central star positions if available. This power of the VLT allows providing never-seen-before features and central stars in previous studies. Then, the raw long-slit spectra are reduced and corrected for interstellar extinction using the observed hydrogen Balmer decrements. To determine the abundances a classical temperature-based empirical method used in Gorny(2009) will be used. Photo-ionization models based on the Cloudy code will be obtained to extend our understanding.

Anyone interested is welcome to attend.