Science

The recent development of high sensitivity infrared spectrometers has opened a totally new window of astronomical researches. Indeed, the investigation of the 1-2.4 micron band has yield the discovery of a wealth of diagnostic tools, both in terms of absorption stellar features and emission lines, which allowed a thorough understanding of several astronomical objects in both the local and high-z Universe.

The much reduced extinction at these wavelengths allows IR spectrometers to pierce the dust embedding several Galactic and extragalactic objects, which are heavily obscured in the optical. At high redshift several emission and absorption spectral features, commonly exploited when studying local galaxies, are shifted into the IR. These and several other advantages of IR spectroscopy have yield to a rapid growth of the community of astronomers, from essentially any scientific fields, making use of these facilities.

Yet, a further development of several IR spectroscopic studies is now facing a shortage of instruments working at high spectral resolution and covering a wide spectral range (from 0.9 to 2.5 micron) in a single exposure. These characteristics will allow to tackle with unprecedented accuracy several important astronomical issues.

Extra-solar rocky planets.

The capability of GIANO to simultaneously measure a huge number of near-IR features at high resolving power will make it the optimal tool, without any competitor, in the search for low-mass, rocky planets around cool low-mass stars.

Brown Dwarfs.

It has been recently shown that a wide, continuous spectral coverage in the near-IR is the optimal tool for the classification of very low mass stars and brown dwarfs. The high spectral resolution capabilities of GIANO will allow first quantitative spectroscopy to study the chemical composition of their atmosphere and their circumstellar activity.

Star-forming regions.

By studying the velocity structure of suitable emission lines in star-forming regions it will be possible to obtain fundamental information on accretion/ejection mechanisms in active protostars and on how the activity of low mass young stars evolves from the embedded to the pre-main sequence phase.

Cool stellar atmospheres.

The unique combination of high spectral resolution, wide spectral coverage, polarimetric capabilities and high sensitivity will allow to derive with unprecedented accuracy the abundances of most atomic and molecular species, the magnetic fields and the mass loss activity in any class of cool star. This information is crucial for our understanding of the stellar physics, evolution and chemical enrichment.

Extragalactic stellar clusters.

GIANO can provide high resolution, near IR integrated spectra of stellar clusters in the local Group and beyond, allowing to determine both their chemical composition and dynamical mass, and constrain the star formation history and chemical enrichment of their host galaxies.

Black Holes in obscured AGNs.

GIANO will allow to tightly constrain the Black Hole mass in several galactic nuclei which are too obscured by dust to be probed by optical spectrometers. This is in particular the case for obscured AGNs, which are largely the dominant population of active nuclei.

IMF in starburst galaxies.

By resolving the width of absorption and emission features in dust embedded Super Star Clusters (found in starburst galaxies) it will be possible to tightly constrain their dynamical mass and Initial Mass Function (IMF). Henceforth, it will be possible to investigate the dependence of the IMF on the level of activity and metallicity of these systems, which is highly relevant for our understanding of the formation and evolution of stellar systems.

Damped Ly-alpha Systems.

GIANO will allow to determine the metallicity of high-z Damped Ly-alpha Systems illumintated by bright/lensed QSO and GRBs, by measuring the equivalent width of the associated absorption by various atomic species, which are shifted into the near-IR. This will provide tight constraints to the metallicity evolution of Damped Ly-alpha Systems, which is currently poorly known because of the shortage of indicators in the optical at high redshift.

Polarimetric mode

Polarimetry in the near IR is still an almost unexplored diagnostic tool. The polarimetric unit of GIANO can represent a unique facility to perform IR polarization measurements in different astrophysical environments. Several physical mechanisms are indeed responsible for linear and/or circular polarization of the radiation from astronomical objects, namely: