M. J. Creech-Eakman

New Mexico Institute of Mining and Technology, Socorro, New Mexico, United States

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Publications (128)213.02 Total impact

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    ABSTRACT: ICONN is a dedicated fringe tracker for the Magdalena Ridge Observatory Interferometer (MROI) that employs a baseline bootstrapping combination scheme utilizing the interferometer's "Y"-shaped telescope array. The ICONN optomechanics are designed in a modular fashion to combine light from two to ten telescopes while tracking on the nearest neighbor baselines. The software tasked with operating ICONN is designed to interface with the larger MROI software supervisory system. Commands are distributed to high level processes within ICONN, which in turn pass them down internally to lower level threads. The design of ICONN is now complete and laboratory testing has commenced. This paper details the optomechanical and software design of ICONN.
    Journal of Astronomical Instrumentation. 01/2014; 02(02).
  • Donald G. Luttermoser, M. J. Creech-Eakman, T. Gueth
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    ABSTRACT: We report on the first set of IR spectra taken of Mira-type variable stars under high dispersion with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. A sample of 25 galactic Miras was observed in the 10-37 micron spectral regime anywhere from two to several times during their pulsation cycle. Many of the stars observed show marked changes in overall flux levels as a function of phase. We are able to identify many strong emission lines and emission features due to silicate and carbon dusts and molecular constituents. In addition, strong emission lines from neutral and singly ionized metals were also seen. Finally, a strong absorption feature was seen near 13.7 microns in the carbon star U Lyr at six different phases spanning 0.572 to 0.909 of the pulsational phase. This absorption feature is likely due primarily to the Q, v5 band at 13.70978 microns of the C2H2 molecule, with perhaps some contamination of the n5 band of CHCH at 13.716 microns. This work was financially supported through a NASA Spitzer grant for Program GO 50717.
    01/2014;
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    ABSTRACT: Ground-based observations have yielded a wealth of new and unexpected information regarding the atmospheric composition and structure of transiting exoplanets. When considered in conjunction with space-based data, we have the potential to form a more complete picture of the atmosphere of an exoplanet. We present a day-side, emission spectrum of the transiting hot-Jupiter WASP-1b. Our spectrum is based on three secondary eclipses obtained using the mid-resolution spectrograph SpeX at the NASA Infrared Telescope Facility (IRTF) (this work) and Spitzer/IRAC observations of two secondary eclipses (Wheatley et al. 2010, draft). We find that our IRTF/SpeX flux densities are notably brighter than the typical brightness temperatures implied by the longer wavelength data. A more coherent picture of the atmosphere of WASP-1b requires additional observations with improved spectral resolution.
    01/2014;
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    ABSTRACT: Phase shifting interferometry relies on sets of interferograms taken at multiple known phase offsets to deduce the instantaneous phase of a quasi-static fringe pattern. The traditional method for introducing these phase shifts has been either to step a mirror, and measure the fringe pattern at each step, or to scan a mirror, integrating the fringe pattern for discrete time intervals while the fringes "move" on the detector. A stepping mirror eliminates this fringe smear but has typically required a closed-loop controller to ensure that the optical path introduced is accurately known. Furthermore, implementing rapid stepping of a moderately sized optic can prove difficult if the fringe phase needs to be measured on a short time scale. We report results demonstrating very fast (>100 Hz) and precise phase shifting using a piezomodulated mirror operated in open-loop without any position feedback. Our method exploits the use of a synthetic driving waveform that is optimized to match the complex frequency response of the modulator and its supported optic. For phase measurements in the near-infrared at 2.15 μm, and with a time between steps as small as 0.2 ms, we report errors below λ/100 in the desired position of our optic, i.e., an effective optical path difference error of ∼λ/55. For applications in near-infrared stellar interferometry, this implies an enhancement in the fringe-tracking sensitivity of roughly 20% (in the photon-limited regime) over that which is conventionally realized using a swept mirror.
    Applied Optics 07/2013; 52(20):4922-4932. · 1.69 Impact Factor
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    ABSTRACT: We describe the scientific motivation for and conceptual design of the Magdalena Ridge Observatory Interferometer, an imaging interferometer designed to operate at visible and near-infrared wavelengths. The rationale for the major technical decisions in the interferometer design is discussed, the success of the concept is appraised, and the implications of this analysis for the design of future arrays are drawn out.
    07/2013;
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    ABSTRACT: To produce a high quality science product, optical and near infrared interferometers must battle the shakes, bumps, and rattles of the environment while correcting for the constantly changing atmosphere. The planned Magdalena Ridge Observatory Interferometer (MROI) will have baselines up to 347 meters requiring beam transport of the same scale. Thus alignment of the beam transport system is crucial and can pose a significant reduction in time available for observations due to both the standard beginning of night alignment and how misalignments arising overnight are detected and corrected. For high contrast fringes to be continuously observed, the turbulent atmosphere must also be tracked and its effects minimized. This poster overviews some subsystems of the MROI responsible for minimizing the effort needed for alignment and correcting atmospheric effects with focus on the laboratory demonstration of the systems.
    10/2012;
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    ABSTRACT: NESSI: the New Mexico Tech Extrasolar Spectroscopic Survey Instrument is a ground-based multi-object spectrograph that operates in the near-infrared. It will be installed on one of the Nasmyth ports of the Magdalena Ridge Observatory (MRO) 2.4-meter Telescope. NESSI operates stationary to the telescope fork so as not to produce differential flexure between internal opto-mechanical components during or between observations. In this paper we report on NESSI's detailed mechanical and opto-mechanical design, and the planning for mechanical construction, assembly, integration and verification.
    Proc SPIE 09/2012;
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    ABSTRACT: NESSI: the New Mexico Tech Extra(solar)planet Spectroscopic Survey Instrument is a ground-based multi-object spectrograph that operates in the near-infrared and is being deployed this fall at the Magdalena Ridge Observatory 2.4 m telescope. When completed later this year, it is expected to be used to characterize the atmospheres of transiting exoplanets with unprecedented ground-based accuracies down to about K = 9 magnitude. The superior capabilities of NEESI for this type of work lay, in part, in the design philosophy used for the instrument which is well-focused on the exoplanet case. We report here on this design philosophy, detail and status of the design and assembly, and preparation for first light in the fall of 2012.
    Proc SPIE 09/2012;
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    ABSTRACT: The Magdalena Ridge Observatory Interferometer has been designed to be a 10 x 1.4 m aperture long-baseline optical/near-infrared interferometer in an equilateral "Y" configuration, and is being deployed west of Socorro, NM on the Magdalena Ridge. Unfortunately, first light for the facility has been delayed due to the current difficult funding regime, but during the past two years we have made substantial progress on many of the key subsystems for the array. The design of all these subsystems is largely complete, and laboratory assembly and testing, and the installation of many of its components on the Ridge are now underway. This paper serves as an overview and update on the facility's present status, and the plans for future funding and eventual operations of the facilities.
    Proc SPIE 07/2012;
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    ABSTRACT: Interferometry provides the only practicable way to image meter-scale structure in geosynchronous satellites. This capability represents a unique commercial opportunity for astronomical interferometry, but to date no interferometer has been able to make an image of such a satellite. We discuss the challenges of imaging these objects and present results of sensitivity calculations and imaging simulations which show that the Magdalena Ridge Observatory Interferometer is likely to be well-suited to this application. Our preliminary results suggest that a significant proportion of GEO targets may be accessible and that it may be possible to routinely extract key satellite diagnostics with an imaging capability that would be able to distinguish, for example, 70 cm features on a 5-meter satellite bus and payload, 30 cm features on a 2-meter satellite bus or similarly sized structure, as well as precise quantitative information on much larger structures such as 10 m long solar panels. Optimised observation and data reduction strategies are likely to allow these limits to be improved in due course.
    Proc SPIE 07/2012;
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    ABSTRACT: Most subsystems of the Magdalena Ridge Observatory Interferometer (MROI) have progressed towards final mechanical design, construction and testing since the last SPIE meeting in San Diego - CA. The first 1.4-meter telescope has successfully passed factory acceptance test, and construction of telescopes #2 and #3 has started. The beam relay system has been prototyped on site, and full construction is awaiting funding. A complete 100-meter length delay line system, which includes its laser metrology unit, has been installed and tested on site, and the first delay line trolley has successfully passed factory acceptance testing. A fully operational fringe tracker is integrated with a prototyped version of the automated alignment system for a closed looping fringe tracking experiment. In this paper, we present details of the final mechanical and opto-mechanical design for these MROI subsystems and report their status on fabrication, assembly, integration and testing.
    Proc SPIE 07/2012;
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    ABSTRACT: The characterization of ICoNN, the Magdalena Ridge Observatory Interferometer's fringe tracker, through labor­ tory simulations is presented. The performance limits of an interferometer are set by its ability to keep the optical path difference between combination partners minimized. This is the job of the fringe tracker. Understanding the behavior and limits of the fringe tracker in a controlled environment is key to maximize the science output. This is being done with laboratory simulations of on-sky fringe tracking, termed the closed-loop fringe experi­ ment. The closed-loop fringe experiment includes synthesizing a white light source and atmospheric piston with estimation of the tracking error being fed back to mock delay lines in real-time. We report here on the progress of the closed-loop fringe experiment detailing its design, layout, controls and software.
    Proc SPIE 07/2012;
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    ABSTRACT: We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental questions concerning the formation and evolution of circumstellar disks and planets which can be addressed in the near future with optical and infrared long-baseline interferometers. Furthermore, the importance of complementary observations with long-baseline (sub)millimeter interferometers and high-sensitivity infrared observations is outlined.
    Astronomy and Astrophysics Review 03/2012; · 9.50 Impact Factor
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    ABSTRACT: We show some preliminary 10-37 micron high-resolution spectra taken with the Spitzer Space Telescope in 2008-9 of Mira variables distributed across the M, S and C chemical subclasses. Our entire Spitzer sample of 25 galactic Miras was observed from two to several times during this observing campaign and all have simultaneously measured near-infrared interferometric diameters acquired using the Palomar Testbed Interferometer. Because our sources are very bright for Spitzer IRS (typically 5-100 Janskys), we have excellent signal to noise and for many sources see marked changes in overall flux levels as a function of phase. Further, we are able to identify many strong emission lines and emission features due to silicate and carbon dusts and molecular constituents. We introduce the sample and the design of our experiment, discuss the data reduction required for such bright sources using Spitzer, show several examples of spectra with phase and discuss some preliminary findings. Finally, we discuss future steps for Paper II, to be presented later in the year.
    The Astronomical Review. 01/2012;
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    ABSTRACT: All of the design work and major construction has been completed for the Magdalena Ridge Observatory interferometer (MROI). The majority of the subsystems are currently (2012) being assembled. When completed, the array will consist of 10 fully transportable 1.4 m telescopes. These will support multiple array configurations, with baselines from 7.8 m to 346 m to give sub-milliarcsecond angular resolution. We provide an assessment of the potential imaging capability of the MRO interferometer with regard to geosynchronous targets. Our preliminary results suggest that a significant proportion of GEO targets may be accessible and that it may be possible to routinely extract key satellite diagnostics with an imaging capability that would be able to distinguish, for example, 70 cm features on a 5-meter satellite bus and payload, 30 cm features on a 2-meter satellite bus or similarly sized structure, as well as precise quantitative information on much larger structures such as 10 m long solar panels. Optimised observation and data reduction strategies are likely to allow these limits to be improved in due course.
    Aerospace Conference, 2012 IEEE; 01/2012
  • Heather Bloemhard, M. Creech-Eakman, P. D. Deroo, M. Zhao
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    ABSTRACT: Of the more than 500 known exoplanets, the detailed chemical composition of only a handful of exoplanet atmospheres is known. We endeavor to remedy this imbalance by using ground-based spectroscopy, which has been demonstrated to reliably reproduce space-based results (Swain et al., Nature 463, 2010) while obtaining new and unexpected information. Our IRTF/SpeX SXD (0.8-2.4 micron cross-dispersed) observations of two secondary eclipses of the exoplanet WASP-1b, obtained September and October 2010, will be used to accomplish two main goals: first, to extend the application of exoplanet ground-based spectroscopy to a wider range of targets than are presently characterized; and second, to probe the temperature structure and begin to characterize the composition of the dayside of the atmosphere. We will show our data reduction steps and initial results based on the reduction method introduced by the Exospec team (Swain et al., Nature 463, 2010) WASP-1b is a 1.44±0.04 RJ, 0.89±0.11 MJ exoplanet in a 2.52 day orbit around its parent star (Cameron et al., MNRAS 375, 2007; Charbonneau et al., ApJ 638, 2007). It has a very low density, which puts it in a group of highly irradiated hot-Jupiters with overly inflated radii known as pM class exoplanets. Theory predicts that we should expect to find a thermal inversion, as well as evidence of H2O and CO (Fortney et al., ApJ, 678, 2008). However, the reason for the inflated radii of these exoplanets is still a matter of great debate (Miller et al., ApJ 702, 2009; Spiegel et al., ApJ 699, 2009; Madhusudhan & Seager, ApJ 725, 2010; Guillot, A&A 520, 2010); determining the structure and composition of the atmospheres of this class of exoplanets may help us sort among competing theories as to the structure and source of the inflated radius.
    05/2011;
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    ABSTRACT: All of the design work and major construction has been completed for the Magdalena Ridge Observatory interferometer (MROI). The majority of the subsystems are currently (2011) being assembled. When completed, the array will consist of 10 fully transportable 1.4 m telescopes. These will support multiple array configurations, with baselines from 7.8 m to 350 m to give sub-milliarcsecond angular resolution. We assess the potential imaging capability of the MRO interferometer with regard to geosynchronous targets. We conclude that a significant proportion of GEO targets may be accessible and that it may be possible to routinely extract key satellite diagnostics with 7 × 7 pixel imaging. This would distinguish, for example, 70 cm features on a 5-meter satellite, or 30 cm features on a 2-meter satellite.
    Aerospace Conference, 2011 IEEE; 04/2011
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    ABSTRACT: This report focuses on recent developments at the Magdalena Ridge Observatory Interferometer (MROI) in three major areas: 1) telescope delivery and array infrastructure construction, 2) installation of the first vacuum delay line and 3) laboratory fringe measurements with the first fringe beam combiner. Construction of the telescope foundations and utilities began in August of 2010 and will be complete in September of 2011 for delivery of the first of ten telescopes. The MROI now has the longest (100m) evacuated fast delay line in the world. Initial performance tests that began in November of 2010 are reported here. First broadband fringe measurements have been recorded in the laboratory with the fringe tracking beam combiner. These measurements demonstrate high optical quality, and visibilities matching the predicted values for its architecture type.
    01/2011;
  • I. Payne, M. Creech-Eakman, V. Romero, D. Buscher, C. Haniff
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    ABSTRACT: The Magdalena Ridge interferometer (MROI) is an optical interferometer that is currently (summer, 2010) in the construction phase. Almost all of the design work has been completed and the majority of the subsystems are being assembled. When completed, the array will consist of 10 fully transportable 1.4m telescopes to support multiple configurations with baselines from 7.5m to 350m to give sub-milliarc second angular resolution. We assess the potential imaging capability of the Interferometer with regard to geosynchronous targets. We conclude that a significant proportion of the GEO targets may be accessible and that it may be possible to routinely extract key diagnostics with 7x7 pixel image and could distinguish 70cm features on a 5-meter satellite, or 30cm features on a 2-meter satellite.
    09/2010;
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    ABSTRACT: The Magdalena Ridge Observatory Interferometer is a 10 x 1.4 meter aperture long baseline optical and near-infrared interferometer being built at 3,200 meters altitude on Magdalena Ridge, west of Socorro, NM. The interferometer layout is an equilateral "Y" configuration to complement our key science mission, which is centered on imaging faint and complex astrophysical targets. This paper serves as an overview and update on the status of the observatory and our progress towards first light and first fringes in 2012.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    07/2010;

Publication Stats

537 Citations
213.02 Total Impact Points

Institutions

  • 2008–2014
    • New Mexico Institute of Mining and Technology
      • Department of Physics
      Socorro, New Mexico, United States
  • 2000–2009
    • California Institute of Technology
      • • Division of Geological and Planetary Sciences
      • • Jet Propulsion Laboratory
      Pasadena, CA, United States
  • 1996–2002
    • University of Wyoming
      • Department of Physics and Astronomy
      Laramie, Wyoming, United States