On the high-resolution spectroscopic requirements for the studies of the cosmological variation of fundamental constants
By: Hum Chand
Abstract: In this talk, we will first briefly summarize the TMT
science case on the cosmological variation of fundamental constants.
We will then discuss the key systematics involved in these studies.
Finally, we will summarize the wish list of the high resolution
spectroscopic requirements of TMT for such studies, based on
our analysis with the existing high-resolution spectroscopy using
8-10 m class telescopes.
Performance Estimates for Ground Layer Adaptive Optics at TMT
By: Brent Lee Ellerbroek
Abstract: In this presentation we will summarize recent adaptive optics performance modeling of ground layer adaptive optics (GLAO) at TMT. GLAO can provide a significant improvement to enclosed and enslitted energy over the WFOS field-of-view over a wide wavelength range and at both potential TMT sites. We present results on how the h=-280 m conjugate range of the TMT adaptive secondary mirror (AM2) impacts the uniformity of the GLAO correction across the WFOS field-of-view, and how the GLAO asterism can be adjusted to minimize the non-uniformity. We conclude with several comments on potential AM2 design concepts.
Co-Authors: B. L. Ellerbroek, L. Wang
The gas mass and star formation rate of star-forming galaxies at z>1
By: Nissim Kanekar
Abstract: Optical and radio imaging and spectroscopy provide complementary views of galaxies,
probing, respectively, the stars and the gas. While optical studies of various deep fields
have yielded detailed information on the stellar properties of star-forming galaxies out to high redshifts, z>>1, little is known about the atomic gas in galaxies at z>~0.25, due to the weakness of the HI 21cm line. For large galaxy samples, ``stacking'' of the redshifted HI 21cm emission from the different galaxies allows us to achieve a far higher HI mass sensitivity than would be possible for individual objects. After outlining the requirements for HI 21cm stacking experiments, I will describe results from the first such study at z>1, using Giant Metrewave Radio Telescope (GMRT) HI 21cm spectroscopy of the DEEP2 Survey fields to probe the atomic gas mass of star-forming galaxies at z~1.3. I will also discuss results from our stacking of the rest-frame 1.4 GHz radio continuum from the DEEP2 galaxies, which allows us to determine the total median star formation rate (SFR) of the DEEP2 galaxies from the radio-far infrared correlation, and to study the dependence of the median SFR on various galaxy properties. Finally, I will discuss prospects for such studies over the next decade,
using the new receivers and backend of the upgraded GMRT and spectroscopic studies with the Wide Field Optical Spectrograph on the Thirty Meter Telescope.
Co-Authors: Shiv Sethi (Raman Research Institute, Bengaluru, India) Apurba Bera (National Centre for Radio Astrophysics, Pune, India) K. S. Dwarakanath (Raman Research Institute, Bengaluru, India) Ben Weiner (University of Arizona, Tucson, USA)
Characterizing Exoplanets with High Dispersion Coronagraphy on TMT
By: Dimitri Mawet
Abstract: High-dispersion coronagraphy (HDC) optimally combines high-contrast imaging techniques such as adaptive optics/wavefront control plus coronagraphy to high spectral resolution spectroscopy. HDC enables the full characterization of exoplanet atmospheres across a broad range of masses from giant gaseous planets down to Earth-like planets. In addition to determining molecular compositions, HDC also enables Doppler mapping of atmosphere inhomogeneities (temperature, clouds, wind), as well as precise measurements of exoplanet rotational velocities (length of day). Here, we present results from end-to-end numerical simulations and the laboratory demonstration of an innovative concept for injecting the directly imaged planet light into a single-mode fiber, linking a high-contrast adaptively corrected coronagraph to a high-resolution spectrograph. Our proof of concept in the Caltech Exoplanet Technology Laboratory includes three key milestones: close-to-theoretical injection efficiency, accurate pointing and tracking, and on-fiber coherent modulation and speckle nulling of spurious starlight signal coupling into the fiber. Using the extreme modal selectivity of single-mode fibers, we also demonstrated speckle suppression gains that outperform conventional image-based speckle nulling. A Fiber Injection Unit demonstrator based on the HDC concept will soon be deployed at W.M. Keck Observatory, as part of the Keck Planet Imager and Characterizer (KPIC). The KPIC FIU will proof-test HDC on segmented telescopes, a stepping stone towards the future TMT Planetary System Imager (PSI).
Co-Authors: J. Wang, N. Jovanovic, G. Ruane, J.R. Delorme, N. Klimovich, D. Echeverri, J.K. Wallace, J. Llop, W. Xuan, Y.Yeyuan
Solar System Small Body Science and the TMT
By: Karen Jean Meech
Small solar system bodies (asteroids, comets, small moons, Centaurs and Kuiper belt objects) hold keys to understanding the solar system’s formation. They are also frequently targets of small missions, and play a role in astrobiological habitability, in hazards to Earth’s biosphere, and represent potential future space resources. After more than four decades of work, the asteroid population is yielding information about compositional gradients in the protosolar nebula, aqueous alteration processes in the protoplanetary disk and the early dynamic environment as the giant planets formed. Similarly, large surveys of Kuiper belt objects have led to new dynamical models of the solar system’s architecture and a mapping of volatiles outgassed from small bodies are providing chemical clues to this process. Large all-sky small body surveys are discovering new populations of small bodies, and this will significantly increase with LSST. Space missions have demonstrated the type of transformative science gained from detailed understanding of the structure and chemistry of small bodies. This talk will show how both TMT’s first light instruments and the next-generation of instrumentation will transform our understanding of in the context of missions and future large surveys and space facilities.
MICHI, A Thermal-Infrared Instrument for the TMT
By: Chris Packham
Abstract: With the 2018 launch of the JWST, the field of thermal-IR astronomy will enjoy a revolution. It is easy to imagine that all areas of IR astronomy will be greatly advanced, but perhaps impossible to conceive of the new vistas that will be opened. To allow both follow-up JWST observations and a continuance of work started on the ground-based 8m’s, we continue to plan the science cases and instrument design for a thermal-IR imager and spectrometer for early operation on the TMT. When combined with the mid-IR adaptive optics (AO) system (MIRAO), the instrument will afford ~15 times higher sensitivity and ~ 4 times better spatial resolution (0.07”) with a greatly improved and stable Strehl ratio at 10um compared to 8m-class telescopes. Compared to the JWST, MICHI will afford ~4.5 times improved spatial resolution and improved high-contrast imaging. Further, through exploiting the TMT’s large collecting area we plan a high-dispersion spectroscopy mode, unrivaled by the JWST and other space-based observatories. Such capabilities offer the possibility for transformative science, as well as ‘workhorse’ observing modes of imaging and low/moderate spectral resolution. New technology advances hold great promise to significantly improve previous instrument concepts. We present the current status of our science cases and the instrumentation plans, harnessing expertise across the TMT partnership. This instrument will be proposed by the MICHI team as a second-generation instrument in the upcoming call for proposals.
Co-Authors: M. Honda, M. Chun, I. Sakon, M. Richter, Y. Okamoto, M. Puravankara, H. Kataza, C. Marois, M. Meyer, and the MICHI Team
Finding bio-signatures on extrasolar planets, how close are we?
By: Enric Palle
Abstract: Ongoing searches for exoplanetary systems have revealed a wealth of planetary systems with extremely diverse physical properties. Earth-size planets have already been detected around many stellar types, including some interesting planets within the habitable zone of cool M-type stars. Over the coming decades, the efforts of future space missions and large telescope facilities will be aimed at the discovery of small rocky exoplanets within the habitable zones of the brighter stars in the sky providing key targets for further followup.
Once these prime targets are found, efforts will shift toward the characterization of their atmospheres, and the search for possible bio-signatures. This is a daunting task that will require bringing to the limit the capabilities of the largest telescopes in search for faint signatures, that once detected will quite likely become a subject of controversy for several years.
In this talk I will review the subject of planetary-scale detectable biomarkers, their evolution in time, and what are the likely scenarios that TMT and other very large aperture telescopes will face trying to detect these signatures.
Co-Authors: Enric Palle
Systems engineering for future TMT instrumentation
By: Scott C Roberts
Abstract: This talk will present an overview of the TMT system design with a focus on how instruments are integrated into the TMT design. I will present requirements, interfaces and services provided for implementing instruments on the Nasmyth Platforms. This talk will also provide instrument developers with an insight into how top level science and operational requirements flow down to specific instrument requirements at the system and subsystem level requirements. I will also describe the key elements of systems engineering for instrumentation projects.