[Phys-seminars] 2017-06-28 Astrophysics and Cosmology Seminar

zitrin zitrin at bgu.ac.il
Sun Jun 25 10:02:27 IDT 2017

Astrophysics and Cosmology Seminar

 DATE: 28-06-17

 TIME: 11:15

 PLACE: Physics building (#54) room 207

Star formation across cosmic time with the PHIBSS programs

Dr. Jonathan Freundlich, Hebrew University of Jerusalem

Star formation in the Universe experienced a peak ten billion years ago and a subsequent drop by an order of magnitude. As stars are formed within giant molecular clouds, it is crucial to probe molecular gas reservoirs to understand the cosmic evolution of the star formation rate. The PHIBSS and PHIBSS2 programs at the IRAM Plateau de Bure NOEMA interferometer survey the molecular gas properties of galaxies on and around the main sequence, where most of star formation occurs. While the first PHIBSS program uncovered large molecular gas fractions at high redshift, hence showing that the winding-down of star formation was mostly driven by the diminishing cold gas reservoirs, it also hinted at a slight increase of the star formation efficiency near the peak epoch of star formation. The ongoing PHIBSS2 legacy program significantly extends the sample of molecular gas measurements within main sequence galaxies at different redshifts and systematically explores the dependence of the
  gas fraction and the depletion time with redshift, stellar mass, offset from the main sequence and morphology. It notably establishes robust scaling relations encompassing these dependencies, which should guide theoretical models of galaxy formation and evolution.

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