Nov 08, 2012

Nick Konidaris, Caltech

"Initial Results from MOSFIRE: Star Formation Diagnostics"

On 4 April 2012 the Multi-Object Spectrometer For Infrared Exploration
(MOSFIRE) achieved first light at Keck Observatory. Compared to the first
generation infrared spectrograph on Keck, MOSFIRE is over 100x more efficient
for survey work.  MOSFIRE excels in studying emission features redshifted past
1 µm in wavelength. Among a range of commissioning verification work, I used
MOSFIRE to survey the ionizing sources of blue galaxies at redshifts greater
than 0.5.  In the past few years, because of a lack of instruments like
MOSFIRE, a variety of observational diagnostic tools were developed that
combined color or mass with emission line ratios ([O III] to Hβ) in order
to diagnose ionization source.  In this talk I first describe the assembly and
commissioning of MOSFIRE, and then the use of MOSFIRE to measure a full set of
"BPT" emission line ratios in my blue galaxy samples. These ratios are used to
determine ionization source of emission lines galaxies more massive than the
typical stellar mass M*.