Age determination using AnalySED (multi-dimensional SED analysis) Method (data-analysis part). Zhaoyu Zuo 2008-11-06. outline. M83 and data archive SED method Data-analysis steps Proto-type results Some other considerations. About M83. southern grand-design galaxy
Age determination using AnalySED (multi-dimensional SED analysis) Method
band — exposure time — :comments
V — 307+347s
B — 85s: age indicator [The exposure is a little shallow]
U — 190+48s: age indicator
UVW1 — 1051s
UVM2 — 2866s
UVW2 — 2288+1545s
Ks-band: as template to remove old stellar population contamination.
 U and B bands are vital for age determination.
 UV band can break age-extinction degeneracy
 NIR band is crucial for breaking age-metallicity degeneracy.
 include critical phases in stellar evolution, such as the red supergiant (RSG) phase, Wolf-Rayet stars, and the thermally-pulsing AGB (TP-AGB) phase
 include observational high-resolution UV spectra, to allow for the analysis of stellar and interstellar absorption lines and line profiles at various metallicities.
 include gaseous emission lines in the models in a simplified fashion; its contribution becomes important when hot stars providing ionising photons (and thus line emission) are present
3) The annulus radius is 5arcsec, from 5arcsec to 400arcsec.
4) We calculate the intensity ratio (F_uv/F_k) using pixel-by-pixel method firstly, then we can get the median ratio profile using a median value in each annulus
Ratio(F_uw2/F_k)*F_k analysis) Method
The errors of the regions we are most interested in are analysis) Method within 0.1mag
The age uncertainty is mostly within 30Myr.