Astronomy Colloquium (2016 Fall Semester)

* Date

Dec. 19

* Speaker

Jeonghee Rho (SETI Institute and NASA Ames Research Center)

* Title

Herschel and Millimeter Observations of Supernova Remnants

* Abstract

Supernovae (SNe) are among the mostviolent events in the Universe, ejecting gas on galactic scales and returningmaterial from dense molecular clouds into the more diffuse interstellar medium.Recently star-formation activities are frequently found in infrared dark cloudsand the interstellar turbulence may cause the star formation. I presentHerschel and millimeter observations toward supernova remnants. The spectrarevealed rich molecular lines of high-J and low-J CO, water, hydroxyl and a fewatomic lines of oxygen and carbon. A very broad ortho-water line with a widthof 144 km/s was detected from G349.7+0.2, and the 144 km/s component is one ofthe broadest molecular lines detected in the ISM. Numerous high-J CO lines  are detected from G349.7+0.2 while G357.7+0.3shows broad low-J CO but no high-J CO lines. We observe a strong correlationbetween water and hot CO lines. The detection of very broad water line is thedirect evidence of short-lived molecules that have not been destroyed in highvelocity J-shocks. We also present shocked molecular hydrogen lines from HB

3 and detection of broad CO lines. Iwill discuss the abundance and excitation of oxygen−bearing molecules, revisitthe cooling budget by molecules, compare with those in other objects such asprotostars and star-forming regions, and discuss the impact of turbulence dueto the shock to star-formation.

 I will introduce two large telescopeprojects that I participate in. The Stratospheric Observatory for InfraredAstronomy (SOFIA) is a 2.5 m air-born telescope, flying above more than 99% ofatmospheric water vapor, avoiding strong telluric absorption lines. I will showscience capabilities of the imaging and spectroscopy instruments in the near-IRto far-IR. I will also present the introduction of the Large Synoptic SurveyTelescope

(LSST) project, the LSST observingstrategy and its optimization for SN science, and ideas of the LSST follow-upoptical/infrared spectroscopy.