December 13, 2017, 3:30 p.m.
**** Building 36, Room C211
OHIO STATE UNIVERSITY
"Knowing the Universe
We study the universe through
the radiation of photons from astronomical objects reaching us.
These photons are emitted by atoms and molecules, mostly atoms,
either in the plasma of an astronomical object or traveling in
the space in-between them. Due to quantum energy levels the
emitted photons are of particular wavelengths, which are the
signatures to identify the atoms. They also determine the space
observation either by ground-based telescopes or space-based
observatories. Photometry and imaging give size, location,
distance and limited information on plasma contents of an
astronomical object; spectroscopy gives the maximum information.
The spectrum includes both the emission and the absorption lines
which provide information on the physical conditions of plasma
density and temperature, chemical composition and their
abundances, even presence of a black hole. It is important to
understand the underlying science of the radiation, how they are
produced by the atoms and the types, and harness the knowledge
for our benefits such as understanding the sun, events on the
earth and space; even for applications in medicine.
About the Speaker:
Sultana Nahar received a Ph.D. in atomic theory from Wayne State
University. She is the recipient of the Distinguished Alumni
award. Her research interests include: Atomic astrophysics -
photoionization, electrion-ion recombination, radiative
transitions and lifetimes, and collisional excitations. She is a
member of the international Opacity Project and the Iron Project
to study atomic processes, calculate large sets of atomic
parameters with high accuracy, and develop astrophysical
applications. She is called the “Iron Lady” for her extensive
work on iron. A.K. Pradhan, Y. Yan and Nahar introduced
"Resonant nano-plasma for Theranostics" for cancer treatment.
Her publications include over 150 scientific papers and 15 news
articles on international STEM education and research. She
maintains the database NORAD-Atomic-Data for energies,
oscillator strengths and lifetimes, photoionization cross
sections, and recombination rates. She is an APS fellow, was
named APS Woman Physicist of the Month, and received the John
Wheatley Award of APS. She is the co-author of the textbook
Atomic Astrophysics and Spectroscopy (Cambridge U press). She
has STEM education and research programs in Bangladesh, Egypt,
India, Palestine, and the USA.
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