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start [2016/08/31 11:00]
aaronb [Key Science Cases] 		start [2016/09/08 00:31] (current)
aaronb [Disc & Planetary Formation/Evolution, Exoplanets]
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 //​TMT'​s Guide Through Thermal-Infrared Darkness// //​TMT'​s Guide Through Thermal-Infrared Darkness//
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 +----
  
 MICHI is a possible 2nd generation instrument for the Thirty Meter Telescope (TMT). The **M**id-**I**frared **C**amera with **H**igh spectral resolution and **I**FU. It is the result of a collaboration initiated by astronomers in the USA and Japan, and has now expanded to include representatives from all the partner countries of the TMT consortium. MICHI is a possible 2nd generation instrument for the Thirty Meter Telescope (TMT). The **M**id-**I**frared **C**amera with **H**igh spectral resolution and **I**FU. It is the result of a collaboration initiated by astronomers in the USA and Japan, and has now expanded to include representatives from all the partner countries of the TMT consortium.
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 Through observations of gas in discs, the interstellar medium, comments, and other environments,​ MICHI offers the opportunity to investigate the abundance of prebiotic compounds that led to emergence of life on Earth. Through observations of gas in discs, the interstellar medium, comments, and other environments,​ MICHI offers the opportunity to investigate the abundance of prebiotic compounds that led to emergence of life on Earth.
 +==== Extragalactic Observations ====
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 +{{ michi:​extragalactic.jpg|}}The Decadal Survey stressed the importance of extragalactic supermassive black holes (SMBH) to both astrophysics and cosmology. These is a clear connection between the SMBH and galaxy properties, as shown through the famous M<​sub>​BH</​sub>​ vs. M<​sub>​bulge</​sub>​ and M<​sub>​BH</​sub>​ vs. σ relationships,​ demonstrating that the galaxy bulge mass (M<​sub>​bulge</​sub>​) and the stellar velocity dispersion (σ) are tightly correlated with (M<​sub>​BH</​sub>​),​ despite being on widely different spatial scales. This correlation strongly implies some form of co evolution between the SMBH growth and the galaxy bulge, but the precise nature of this relationship remains uncertain. Understanding this relationship will help to address two crucial questions in cosmology:
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 +  * Which formed first, the SMBH or the galaxy?
 +  * How did SMBHs form so soon after the big bang?
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 +The SMBH will often show a level of '​activity'​ arising through accretion of gas and dust, leading to an Active Galactic Nuclei (AGN). The study of AGN has recently been invigorated through high-spatial resolution observations of the torus in 8-m class telescopes. These observations have shown a complex, clumpy, and probabilistic unification scheme, with tentative hints that the torus structure is (partially) dependent on the level of AGN activity. Possible other effects could be the level of radio emission (radio loud/quiet AGN) and that of the host galaxy, as well the precise fueling of AGN. The complex interplay between the host galaxy and AGN remains poorly constrained,​ and is a goal of the Decadal Survey.
 +
 +====Disc & Planetary Formation/​Evolution,​ Exoplanets====
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 +{{ :​bc32349ee0954bd699794f123220c597_isqchp.jpg|}}
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 +The TMT will have sufficient point-source sensitivity to permit direct detection of gas giants, achieving a '​tipping'​ point in sensitivity to achieve this exciting goal. In a gas is in thermal equilibrium with irradiation by the central star, MICHI will be capable of detecting such giants at a distance of a few AU from nearby (~10 pc) early type (AFG type) stars. If a young (~1 Gyr) planet'​s temperature is determined by its own internal heating (Burrows et al. 2004), detectability is easier. MICHI observations of gas giants holds the promise of the characterization ~5 times closer to the central star than MIR space-based facilities due to the superior spatial resolution.
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 +MIR molecular absorption bands and lines (i.e. NH3 and CH4) can be detected with low- and high-angular resolution spectroscopy,​ and in particular, the 10.5 μm NH3 absorption band is a unique indicator of low temperature (< 1,000 K) planets, only accessible in the MIR. Such information has extremely valuable information on planetary atmospheres.
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 +Existing near- and mid-IR observations of planet forming regions, protoplanetary and debris discs, have revealed astonishing pictures of pleat forming discs such as spirals, gaps, holes and, dips, which strongly imply that planets are forming there. Further, the volition of dust, the key ingredient of planets, such as grain growth and crystallization have been observed. However, these are challenging observations from 8-m class observatories. The spatial resolution and sensitivity of MICHI will be crucial to dramatically increase the number of available sources, conduct statistically significant surveys, and probe the disc chemistry.
 +
 +====== MICHI'​s Design ======
 +
 +Based on the science drivers, we summarize important required capatibilities for MICHI may include:
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 +   * Imaging in the N (7.3-13.5 μm) band 
 +   * Low-dispersion spectroscopy in the N, M, and N bands with R~ a few hundred
 +   * High-strehl imaging at the L, M, N bands with R ~100,​000 ​
 +   * Thermal IR AO system, which enables high-strehl,​ high-sensitivity imaging and lower dispersion.
 +   * Cold internal chopper to enable high-sensitivity imaging and lower dispersion spectroscopy
 +   * Integral field spectroscopic capability with the low-dispersion (R~250 to 1000) and ~2" x 5" FOV
 +   * Polarimetry in both imaging and low-dispersion spectroscopic modes (TBC)
 +