Studying the Reionization Epoch with Superconducting On-Chip Spectroscopy

About the program

The NASA Postdoctoral Program (NPP) offers unique research opportunities to highly-talented scientists to engage in ongoing NASA research projects at a NASA Center, NASA Headquarters, or at a NASA-affiliated research institute. These one- to three-year fellowships are competitive and are designed to advance NASA’s missions in space science, Earth science, aeronautics, space operations, exploration systems, and astrobiology.

Description

The Reionization epoch, when the ensemble of young galaxies produce sufficient hydrogen-ionizing photons to change the state of the intergalactic gas is a complex and incompletely understood period in cosmic history. The process has star formation at its core, but additional factors such as the UV photon escape fraction and recombination rates are important. Line intensity mapping (LIM) in far-IR through millimeter waveband is an emerging technique to study this epoch in a manner complementary to galaxy surveys. By using the Fourier-domain clustering signal imprinted by the structure of the Universe, LIM measures all the light emitted in a given epoch, regardless of whether it originates from many faint sources or a few bright ones. This is a powerful attribute since this period is believed to be dominated by low-luminosity galaxies. LIM using the fine-structure transitions such as the 158-micron [CII] transition can provide an initial constraint on the total star formation activity, while future measurements of other higher-frequency lines can both refine this estimate and provide insights into stellar populations and early black holes, heavy element production, and feedback / regulation at these early times.

Research

We are developing instruments for this type of measurement from ground-based, balloon-borne and space-borne platforms throughout the far-IR to millimeter band. They require moderate-resolving power, but large-format field-filling spectrometers, with large arrays of background-limited detectors. To overcome the size limitations of classical grating spectrometers (particularly limiting in the millimeter band), we have pioneered a superconducting integrated circuit spectrometer SuperSpec; which combines a millimeter-wave filterbank with an integrated kinetic inductance detector array on a small (few square-centimeter) silicon chip. We are beginning a demonstration campaign with a small instrument housing six SuperSpec spectrometer chips at the Large Millimeter Telescope (LMT), this is primarily for galaxy by galaxy follow-up. Meanwhile, we are now planning for a much larger, dedicated millimeter-wave intensity mapping instrument for a low-background terrestrial site.

Opportunities

• Participate in LMT campaigns coming underway soon
• Build on the SuperSpec architecture to create the next-generation focal plane which carries ~100 or more spectrometer pixels
• Play a leading role in a collaboration to field and use this new instrument
• Contribute to the development of ultra-sensitive far-IR detectors for space-borne platforms
• Integration and fielding of the Terahertz Intensity Mapper (TIM) balloon-borne spectrometer

References

• Hailey-Dunsheath, S., Shirokoff, E., et al., 2014. ""Status of SuperSpec: a broadband, on-chip millimeter-wave spectrometer,"" Proceedings of the SPIE, v. 9153, ID 91530M.
• Shirokoff, E. et al., 2014, ""Design and Performance of SuperSpec: An On-Chip KID-Based, mm-Wavelength Spectrometer,"" Journal of Low Temperature Physics, v. 176, 657-662.
• Redford, J. et al, 2018. The design and characterization of a 300 channel, optimized full-band millimeter filterbank for science with SuperSpec, Proc. SPIE, 10708, 107081O.
• Wheeler, J. et al, 2016. SuperSpec: development towards a full-scale filter bank. Proc. SPIE, 9914, 99143K.

Location

Jet Propulsion Laboratory
Pasadena, California

Field of Science

Astrophysics

Advisors

Matt Bradford
matt.bradford@jpl.nasa.gov
818.726.8622

Application Instructions

To apply, please visit the NASA Postdoctoral Program website for application instructions and requirements: How to Apply | NASA Postdoctoral Program (orau.org)

Requirements

A complete application to the NASA Postdoctoral Program includes:

• Research proposal
• Three letters of recommendation
• Official doctoral transcript documents

Eligibility

Eligibility is currently open to:

• U.S. Citizens;
• U.S. Lawful Permanent Residents (LPR);
• Foreign Nationals eligible for an Exchange Visitor J-1 visa status; and,
• Applicants for LPR, asylees, or refugees in the U.S. at the time of application with 1) a valid EAD card and 2) I-485 or I-589 forms in pending status

Contact

If you have questions about this opportunity, please email npp@orau.org