Saturday Science Lecture with Mike Nowak on X-ray Astronomy

Observational astronomy is mostly a story about measuring photons with precision — how many are there, what direction are they coming from, when do they arrive, and what are their energies?  The better we can make those measurements the better our understanding of the astrophysical systems that send those photons across the Cosmos to our sky.  A key tool in astrophysical studies is spectroscopy — deciphering photon energies by exploring the rainbow of colors in the light that we detect.  Most of us are familiar with rainbows created either
naturally in a misty sky or intentionally with prisms and diffraction gratings.  But how do we do this when we are talking about X-rays?  It turns out, this is much more difficult, but extremely important for our understanding of the most exotic phenomena in our Universe, such as black holes and neutron stars!  In this talk I will discuss our currently most precise instrument for measuring “X-ray Rainbows”: the Chandra-High Energy Transmission Gratings.  I will then discuss a soon to be launched mission, XRISM, that will use “quantum detectors” to open up a new frontier in X-ray spectroscopy. I will then discus a soon to be proposed X-ray observatory, Arcus (named after the Roman goddess of the rainbow).  One of the prime goals of Arcus will be to use precise measurements of "X-ray rainbows" from distant, supermassive black holes to reveal the “missing matter” in the Universe (that you probably didn’t even realize was missing!)

This lecture will be in person and on Zoom. The Zoom link will be sent via email to everyone on our email list before each lecture. Those wishing to join the email list should email a request to physics@wustl.edu.