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SUMMARY:IR Spectroscopic Tracers for Galaxy Evolution Studies: the Spitzer
 /Herschel database - Juan Fernandez Ontiveros (IAC Tenerife)
DTSTART:20171201T113000Z
DTEND:20171201T123000Z
UID:TALK94987@talks.cam.ac.uk
CONTACT:Martin Haehnelt
DESCRIPTION:The rest-frame mid- to far-IR range contains a unique suite of
  spectral lines and dust features that allow us to determine the physical 
 conditions in galaxies (e.g. density\, ionisation\, heavy element abundanc
 es) using tracers with a feeble response to both extinction and temperatur
 e.\n\nIn this study we present a spectroscopic database of mid- to far-IR 
 fine-structure lines observed with Spitzer/IRS and Herschel/PACS for a sam
 ple of 170 local AGN\, 20 starburst galaxies\, and 43 dwarf galaxies. The 
 observations are compared to a set of Cloudy photoionisation models to est
 imate the physical quantities through the different diagnostic diagrams. T
 he new [OIV]25.9um/[OIII]88um vs [NeIII]15.6um/[NeII]12.8um diagram is pro
 posed as new IR BPT diagnostic diagram\, able to separate: \n1) AGN activi
 ty from any kind of star formation\; and \n2) low-metallicity dwarf galaxi
 es from starburst galaxies. Current stellar atmosphere models fail to repr
 oduce the observed [OIV]25.9um/[OIII]88um ratios\, which are much higher w
 hen compared to the predicted values. Finally\, the ([NeIII]15.6um +[NeII]
 12.8um)/([SIV]10.5um + [SIII]18.7um) ratio is proposed as a promising meta
 llicity tracer to be used in obscured objects\, where optical lines fail t
 o accurately measure the metallicity.\n
LOCATION:Kavli Large Meeting Room\, Kavli Building
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