SPICA will have access to many diagnostic infrared lines.
Help unravel the mechanisms that drove galaxy evolution to create the galaxies we see today.
SPICA is designed to be a powerhouse for understanding galaxy evolution. It is now well established that the bulk of the star formation and supermassive black hole accretion in galaxies took place around 10 billion years ago, at a redshift of z~2. Since most of the energy emitted by stars and black holes at the centres of galaxies is absorbed by dust, understanding the physics of star formation and black hole growth at these epochs requires observations in the far-IR. The build-up of stars and supermassive black holes over cosmic time have roughly similar shapes, with a peak near z~2 and a sharp drop to the present epoch, suggesting that these processes are linked, resulting in the black hole–galactic stellar mass correlation we see in the local Universe. SPICA will trace the co-evolution of Active Galactic Nuclei (AGN) and galaxies with cosmic time.
Star formation and black hole accretion
SPICA will measure the processes behind the dramatically changing rate of galaxy evolution.
Shed light on the connection between the peak in star formation and black hole growth at z~2.
Only SPICA can measure both obscured starbursts and AGN through their IR spectra out to z=4.
Expose the full baryon cycle in galaxies
SPICA will measure AGN feeding and feedback in significant samples out to z~1-2.
Measure key tracers of atomic and molecular infall and outflows of galaxies in the peak epoch of star formation.
SPICA will also reveal the processes that regulate the baryon cycle and star formation in galaxies, connecting stellar evolution with the reservoirs of gas and dust on scales ranging from individual molecular clouds to galaxy clusters. Gas accretion, outflows and energetic feedback play crucial roles in the evolution of galaxies.
Metallicity and Dust
SPICA provides an extinction-free means to determine gas phase metallicity for a wide range of galaxies and redshifts.
SPICA will also off a new view into the mechanisms of dust formation, processing and destruction over cosmic time.
Dust features of high redshift galaxies.
SPICA will quantify the metal build-up in a galaxy population representing up to 80% of the total star formation activity in the Universe. Metals play a major role in gas cooling, cloud collapse, and ultimately the formation of stars and planets. The metallicity in galaxies is determined by the cumulative effects of star formation, outflows, and accretion. By using bright, rest-frame mid-IR spectral tracers unaffected by dust, SPICA will accurately measure the gas-phase metallicity in galaxies over a wide range in redshift. In luminous galaxies, the HI 7-6 recombination line at 12.3μm can also be measured, allowing a direct determination of the abundances of Neon, Sulfur, Nitrogen, and Oxygen.