INSTITUTE FOR ADVANCED STUDY E-mail: Phone: FAS SCHOOL OF NATURAL SCIENCES MATIAS ZALDARRIAGA. PROFESSOR February I, 2015 Dear Colleague, It is a great pleasure to support the nomination of Meng Su for the Origins prize lectureship. I think Meng is an outstanding young scientist with an impressive track record of accomplishments for someone his age. Meng is also very ambitious and thus I am confident he will become one of the leaders in our field. Below I append the letter I sent for Meng earlier this year as part of his job application process. It contains a more detailed assessment. I think Meng is an excellent candidate for your prize. You will not be disappointed if you pick him. In fact I am confident that years down the line the presence of Meng in the list of recipients will be a significant source of pride. Regards Matias October 15, 2014 Dear Colleague, It is a pleasure to write a letter of reference for Meng Su. Meng did his PhD work under the supervision of Doug Finkbeiner at the Harvard astronomy department. I met Meng while I was there and worked with him on several projects. I believe Meng is a very strong scientist, very driven, resourceful and independent. It is a pleasure to support his application. Meng has done very important work analyzing data from the Fermi telescope. His most important result was the discovery of the so-called "Fermi-bubbles," for which he shared the 2014 Rossi Prize with Finkbeiner and Slatyer. This observation might provide direct evidence of "feedback" on our galaxy by its central Black Hole. I believe the detailed study of these structures in the center of our galaxy will prove extremely fruitful in the years to come. Meng devoted significant time to doing detailed modeling of gamma-ray emission from the galactic center and has done very influential work on the claimed 130 GeV line. Meng's work argued for the existence of this line but also uncovered systematic effects in the data that could