Papers by Johannes Staguhn
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 2018
We will present a status update on the development of HIRMES, the third generation instrument for... more We will present a status update on the development of HIRMES, the third generation instrument for SOFIA (Stratospheric Observatory for Infrared Astronomy). HIRMES (HIgh Resolution Mid-infrarEd Spectrometer) will cover the wavelength range between 25 micron and 122 micron with a spectral resolution of up to R~100,000. It will use two arrays of Transition Edge Sensed (TES) bolometers. One of the arrays consists of 8 16-pixel strips, for the high-resolution mode, where the pixel area and backshorts are optimized for 8 different wavelength regimes. The second detector consists of a 16x64 array with excellent sensitivity over the full wavelength range, and it will be used for the mid-resolution (R~19,000) and low-resolution (R~2,000 and R~600) observing modes. Both detector arrays will have background limited performance with NEPs of < 2E-17 W/Hz^(1/2) for the low-resolution array and < 3E-18 W/Hz^(1/2) for the high-resolution array. HIRMES will employ several Fabry-Perot Interfero...
American Astronomical Society Meeting Abstracts #221, 2013
ABSTRACT We present precision photometry and imaging of the core and two radio lobes of the galax... more ABSTRACT We present precision photometry and imaging of the core and two radio lobes of the galaxy Cygnus A at a wavelength of 2 millimeters, taken using the GISMO camera at the IRAM 30m telescope. We also present new 350 micron photometry using the SHARC-II camera at the CSO, archival Spitzer data, and WISE data, all with the aim of producing a precision spectral energy distribution of the synchrotron emission from the two radio lobes along with a single-dish size of the synchrotron-emitting regions. Using a sophisticated mapping approach and with attention to an accurate beamwidth measurement, we are able to determine that the two lobes have an effective emission scale of around 9+/-0.5 arcseconds, and are therefore roughly 10kpc in scale.
The Origins Space Telescope is the mission concept for the Far-Infrared Surveyor, one of the four... more The Origins Space Telescope is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies to be submitted by NASA Headquarters to the 2020 Astronomy and Astrophysics Decadal survey. The observatory will provide orders of magnitude improvements in sensitivity over prior missions, in particular for spectroscopy, enabling breakthrough science across astrophysics. The observatory will cover a wavelength range between 5 μm and 600 μm in order to enable the study of the formation of proto-planetary disks, detection of bio-signatures from extra-solar planet's atmospheres, characterization of the first galaxies in the universe, and many more. The five instruments that are currently studied are two imaging far-infrared spectrometers using incoherent detectors, providing up to R~ 10^5 spectral resolution, one far-infrared infrared heterodyne instrument for even higher spectral resolving powers, one far-infrared continuum imager and polarim...
We present the severe, systematic uncertainties currently facing our understanding of dust emissi... more We present the severe, systematic uncertainties currently facing our understanding of dust emission, which stymie our ability to truly exploit dust as a tool for studying galaxy evolution. We propose a program of study to tackle these uncertainties, describe the necessary facilities, and discuss the potential science gains that would result.
A complete census of dusty star-forming galaxies (DSFGs) at early epochs is necessary to constrai... more A complete census of dusty star-forming galaxies (DSFGs) at early epochs is necessary to constrain the obscured contribution to the cosmic star formation rate density (CSFRD), however DSFGs beyond z ∼ 4 are both rare and hard to identify from photometric data alone due to degeneracies in submillimeter photometry with redshift. Here, we present a pilot study obtaining follow-up Atacama Large Millimeter Array (ALMA) 2 mm observations of a complete sample of 39 850 µm-bright dusty galaxies in the SSA22 field. Empirical modeling suggests 2 mm imaging of existing samples of DS-FGs selected at 850 µm-1 mm can quickly and easily isolate the "needle in a haystack" DSFGs that sit at z > 4 or beyond. Combining archival submillimeter imaging with our measured ALMA 2 mm photometry (1σ ∼ 0.08 mJy beam −1 rms), we characterize the galaxies' IR SEDs and use them to constrain redshifts. With available redshift constraints fit via the combination of six submillimeter bands, we identify 6/39 high-z candidates each with > 50% likelihood to sit at z > 4, and find a positive correlation between redshift and 2 mm flux density. Specifically, our models suggest the addition of 2 mm to a moderately constrained IR SED will improve the accuracy of a millimeter-derived redshift from ∆z/(1 + z) = 0.3 to ∆z/(1 + z) = 0.2. Our IR SED characterizations provide evidence for relatively high emissivity spectral indices (β = 2.4 ± 0.3) in the sample. We measure that especially bright (S 850µm > 5.55 mJy) DSFGs contribute ∼ 10% to the cosmic-averaged CSFRD from 2 < z < 5, confirming findings from previous work with similar samples.
American Astronomical Society Meeting Abstracts #229, 2017
SPIE Proceedings, 2014
ABSTRACT We have demonstrated a kilopixel, filled, infrared bolometer array for the balloon-borne... more ABSTRACT We have demonstrated a kilopixel, filled, infrared bolometer array for the balloon-borne Primordial Inflation Polarization Explorer (PIPER). The array consists of three individual components assembled into a single working unit: 1) a transition-edge-sensor bolometer array with background-limited sensitivity, 2) a quarter–wavelength backshort grid, and 3) an integrated Superconducting Quantum Interference Device (SQUID) multiplexer (MUX) readout. The detector array is a filled, square–grid of suspended, one-micron thick silicon bolometers with superconducting sensors. The Backshort–Under–Grid (BUG) is a separately fabricated component serving as a backshort to each pixel in the array. The backshorts are positioned in the cavities created behind each detector by the back–etched well. The spacing of the backshort beneath the detector grid can be set from ~30-300_microns by independently adjusting process parameters during fabrication. Kilopixel arrays are directly indium–bump–bonded to a 32x40 SQUID multiplexer circuit. The array architecture is suitable for a wide range of wavelengths and applications. Detector design specific to the PIPER instrument, fabrication overview, and assembly technologies will be discussed.
arXiv: Astrophysics of Galaxies, 2019
We present the severe, systematic uncertainties currently facing our understanding of dust emissi... more We present the severe, systematic uncertainties currently facing our understanding of dust emission, which stymie our ability to truly exploit dust as a tool for studying galaxy evolution. We propose a program of study to tackle these uncertainties, describe the necessary facilities, and discuss the potential science gains that will result. This white paper was submitted to the US National Academies' Astro2020 Decadal Survey on Astronomy and Astrophysics.
The Astrophysical Journal, 2014
Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies wer... more Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts which produce dense remnants. Sub-millimeter selected galaxies (SMGs) are prime examples of intense, gas-rich, starbursts. With a new, representative spectroscopic sample of compact quiescent galaxies at z = 2 and a statistically wellunderstood sample of SMGs, we show that z = 3 − 6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42 +40 −29 Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star-formation. These results suggests a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star-formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.
The Astrophysical Journal, 2014
Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies wer... more Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts which produce dense remnants. Sub-millimeter selected galaxies (SMGs) are prime examples of intense, gas-rich, starbursts. With a new, representative spectroscopic sample of compact quiescent galaxies at z = 2 and a statistically wellunderstood sample of SMGs, we show that z = 3 − 6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42 +40 −29 Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star-formation. These results suggests a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star-formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 2018
The far-IR band is uniquely suited to study the physical conditions in the interstellar medium fr... more The far-IR band is uniquely suited to study the physical conditions in the interstellar medium from nearby sources out to the highest redshifts. FIR imaging and spectroscopy instrumentation using incoherent superconducting bolometers represents a high sensitivity technology for many future suborbital and space missions, including the Origins Space Telescope. Robust, high sensitivity detector arrays with several 10 4 pixels, large focal plane filling factors, and low cosmic ray cross sections that operate over the entire far-IR regime are required for such missions. These arrays could consist of smaller sub-arrays, in case they are tileable. The TES based Backshort Under Grid array architecture which our group has fielded in a number of FIR cameras, is a good candidate to meet these requirements: BUGs are tileable, and with the integration of the SQUID multiplexer scaleable beyond wafer sizes; they provide high filling factors, low cosmic cross section and have been demonstrated successfully in far-infrared astronomical instrumentation. However, the production of BUGs with integrated readout multiplexers has many time and resource consuming process steps. In order to meet the requirement of robustness and efficiency on the production of future arrays, we have developed a new method to provide the superconducting connection of BUG detectors to the readout multiplexers or general readout boards behind the detectors. This approach should allow us to reach the goal to produce reliable, very large detector arrays for future FIR missions.
AST/RO, a 1.7 m diameter telescope for astronomy and aeronomy studies at wavelengths between 200 ... more AST/RO, a 1.7 m diameter telescope for astronomy and aeronomy studies at wavelengths between 200 and 2000 microns, was installed at the South Pole during the 1994-1995 Austral summer. The telescope operates continuously through the Austral winter, and is being used primarily for spectroscopic studies of neutral atomic carbon and carbon monoxide in the interstellar medium of the Milky Way and the Magellanic Clouds. The South Pole environment is unique among observatory sites for unusually low wind speeds, low absolute humidity, and the consistent clarity of the submillimeter sky. Four heterodyne receivers, an array receiver, three acousto-optical spectrometers, and an array spectrometer are installed. A Fabry-Perot spectrometer using a bolometric array and a Terahertz receiver are in development. Telescope pointing, focus, and calibration methods as well as the unique working environment and logistical requirements of the South Pole are described.
We present first and preliminary submillimeter continuum images of the Galactic Center region obt... more We present first and preliminary submillimeter continuum images of the Galactic Center region obtained with the new Caltech Submillimeter Observatory facility camera SHARC II. The instrument allows 350 micron observations with unprecedented sensitivity and instantaneous spatial coverage. The stability of the SHARC II detectors combined with the large number of available pixels allows a non-differential scanning mode that does not require the observation of a reference off-source position. Here we present large-scale 350 micron dust continuum images from the Sgr A and Sgr C regions, as well as the detection of sub-mm dust continuum emission from the IRAS 25 micron source AFGL5376. This source is produced in a large-scale shock that extends well above the Galactic plane.
This White Paper presents a mission concept called MIRECLE - the Mid-InfraRed Exoplanet CLimate E... more This White Paper presents a mission concept called MIRECLE - the Mid-InfraRed Exoplanet CLimate Explorer. With a moderately sized aperture of 2 meters, broad wavelength coverage (4 - 25 um), and next generation instruments, MIRECLE will be capable of efficiently characterizing a statistically significant sample of terrestrial planets, many of which will be in their host stars's habitable zones. Spectroscopic characterization of terrestrial atmospheres will provide constraints for the distribution of planets with tenuous vs. substantial atmospheres, on the inner and outer edges of the habitable zone, and climate models to assess the potential for habitability. For the few brightest targets, the detection of specific combinations of molecules would provide evidence of biosignatures. For all other targets, this comprehensive survey would filter out the airless, desiccated, or lifeless worlds, thus providing a subset of potentially habitable worlds ready for in-depth atmospheric cha...
The Astrophysical Journal, 2018
Millimeter and Submillimeter Detectors For Astronomy Ii, 2004
In order to provide high sensitivity rapid imaging at 3.3 mm (90 GHz) for the Green Bank Telescop... more In order to provide high sensitivity rapid imaging at 3.3 mm (90 GHz) for the Green Bank Telescope-the world&amp;amp;amp;amp;amp;amp;#x27;s largest steerable aperture-a camera is being built by the University of Pennsylvania, NASA/GSFC, and NRAO. The heart of this camera is an 8x8 close-packed, ...
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation For Astronomy V, 2010
We are constructing the Primordial Inflation Polarization Explorer (PIPER) to measure the polariz... more We are constructing the Primordial Inflation Polarization Explorer (PIPER) to measure the polarization of the cosmic microwave background (CMB) and search for the imprint of gravity waves produced during an inflationary epoch in the early universe. The signal is faint and ...
SPIE Proceedings, 2012
ABSTRACT We present the concept for the GISMO-2 bolometer camera, which we build for background-l... more ABSTRACT We present the concept for the GISMO-2 bolometer camera, which we build for background-limited operation at the IRAM 30 m telescope on Pico Veleta, Spain. GISMO-2 will operate simultaneously in the 1 mm and 2 mm atmospherical windows. The 1 mm channel uses a 32 x 40 TES-based Backshort Under Grid (BUG) bolometer array, the 2 mm channel operates with a 16 x 16 BUG array. The camera utilizes almost the entire full field of view provided by the telescope. The optical design of GISMO-2 was strongly influenced by our experience with the GISMO 2 mm bolometer camera which is successfully operating at the 30m telescope. GISMO is accessible to the astronomical community through the regular IRAM call for proposals.
AIP Conference Proceedings, 2009
... Johannes G. Staguhn, Dominic J. Benford, Richard Arendt, David T. Chuss, Dale Fixsen,Jithin G... more ... Johannes G. Staguhn, Dominic J. Benford, Richard Arendt, David T. Chuss, Dale Fixsen,Jithin George, Christine A. Jhabvala, Stephen F. Maher, Timothy M. Miller, S. Harvey Moseley, Elmer H. Sharp, Hans Ungerechts, Edward J. Wollack. Abstract. ...
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Papers by Johannes Staguhn