Event DetailsEvent Dates: Friday, October 24, 2014 - 12:00pmSeminar Location: CASA Conference Room C324Speaker Name(s): Astrid LambertsSpeaker Affiliation(s): University of Wisconsin - Milwaukee Seminar Type/SubjectScientific Seminar Type: Astrophysics Lunch SeminarEvent Details & Abstract: The intergalactic medium (IGM) contains 90 % of the baryons of the Universe and is the reservoir for structure formation. Acting as a calorimeter, its thermal evolution traces the conditions for structure formation and evolution. It was recently shown that TeV blazar heat up the IGM as the gamma-rays they produce turn into pairs which lose their kinetic energy to the surrounding medium through plasma instabilities. Assuming uniform heating, TeV blazar heating increases the temperature of the IGM and produces an inverted temperature-density relation in underdense regions. In this talk I will review the main features of TeV blazar heating. Then, I will detail the method we recently developed to take into account heating fluctuations due to clustering. We find that blazar heating is more complex than initially assumed. The resulting temperature-density relation presents a wide scatter, which is suggested by some recent Ly alpha observations.