The Terahertz intensity mapper (TIM): An imaging spectrometer for galaxy evolution studies at high-redshift

Joaquin Vieira, James Aguirre, C. Matt Bradford, Jeffrey Filippini, Christopher Groppi, Dan Marrone, Matthieu Bethermin, Tzu Ching Chang, Mark Devlin, Oliver Dore, Jianyang Fu, Steven Hailey Dunsheath, Gilbert Holder, Garrett Keating, Ryan Keenan, Ely Kovetz, Guilaine Lagache, Philip Mauskopf, Desika Narayanan, Gergo PoppingErik Shirokoff, Rachel Somerville, Isaac Trumper, Bade Uzgil, Jonas Zmuidzinas

Research output: Contribution to conferencePaperpeer-review

5 Scopus citations


Understanding the formation and evolution of galaxies over cosmic time is one of the foremost goals of astrophysics and cosmology today. The cosmic star formation rate has undergone a dramatic evolution over the course of the last 14 billion years, and dust obscured star forming galaxies (DSFGs) are a crucial component of this evolution. A variety of important, bright, and unextincted diagnostic lines are present in the far-infrared (FIR) which can provide crucial insight into the physical conditions of galaxy evolution, including the instantaneous star formation rate, the effect of AGN feedback on star formation, the mass function of the stars, metallicities, and the spectrum of their ionizing radiation. FIR spectroscopy is technically difficult but scientifically crucial. The FIR waveband is impossible to observe from the ground, and spans a crucial gap in the spectroscopic coverage between the Atacama Large Millimeter/submillimeter Array (ALMA) in the sub/mm, and the James Webb Space Telescope (JWST) in the mid-IR. Stratospheric balloons offer a platform which can outperform current instrument sensitivities and are the only way to provide large-area, wide bandwidth spatial/spectral mapping at FIR wavelengths. NASA recently selected TIM, the Terahertz Intensity Mapper, with the goal of demonstrating the key technical milestones necessary for FIR spectroscopy. TIM will provide a technological stepping stone to the future space-borne instrumentation such as the Origins Space Telescope (OST, formerly the Far-IR Surveyor) or a Probe mission. TIM will address the two key technical issues necessary to achieve this: 1. Low-emissivity, high-throughput telescope and spectrometer optics for the FIR; 2. Background-limited detectors in large format arrays, scalable to >10,000 pixels. We will do this by constructing a integral-field spectrometer from 240 - 420 microns with 3600 kinetic-inductance detectors (KIDs) coupled to a 2-meter low-emissivity carbon fiber telescope. In addition to the development and demonstration of crucial technologies for the FIR, TIM will perform groundbreaking science. We will survey two fields centered on GOODS-S and the South Pole Telescope Deep Field, both of which have rich ancillary data. Scientifically, we will: 1. Obtain spectroscopic line detections of ~100 galaxies in the atomic fine structure lines [CII] (158 microns) (at 0.5<z<1.5), [NII] (205 microns) (at 0.2<z<1), [OI] (63 microns) (at 2.8<z<5.7) and [OIII] (88 microns) (at 1.7<z<3.8); 2. Establish the mean star formation rate (proportional to [CII] luminosity), metallicities (proportional to the [CII]/[NII] ratio), and AGN content (proportional to the [OIII] luminosity) of galaxies using a stacking analysis of known sources in the field; 3. Produce deep maps of the 3D structure of the Universe by redshift tomography (''intensity mapping'') with [CI], and [CII] × [NII] cross-spectra, to constrain the cosmic star formation history at cosmic noon and lay the important groundwork for extending this technique to even higher redshifts to eventually explore the epoch of reionization. In this paper, we will summarize plans for the TIM experiment’s development, test and deployment for a planned flight from Antarctica in Austral summer of 2022-2023.

Original languageEnglish
Number of pages8
StatePublished - 1 Jan 2019
Externally publishedYes
Event2019 30th International Symposium on Space Terahertz Technology, ISSTT 2019 - Gothenburg, Sweden
Duration: 15 Apr 201917 Apr 2019


Conference2019 30th International Symposium on Space Terahertz Technology, ISSTT 2019


  • Astronomy
  • Balloon
  • Intensity mapping
  • Kinetic inductance detector
  • Suborbital


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