Craig Kulesa

The University of Arizona, Tucson, Arizona, United States

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Publications (136)317.27 Total impact

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    ABSTRACT: We report the discovery of a wide co-moving substellar companion to the nearby ($D=67.5\pm1.1$ pc) A3V star $\zeta$ Delphini based on imaging and follow-up spectroscopic observations obtained during the course of our Volume-limited A-Star (VAST) multiplicity survey. $\zeta$ Del was observed over a five-year baseline with adaptive optics, revealing the presence of a previously-unresolved companion with a proper motion consistent with that of the A-type primary. The age of the $\zeta$ Del system was estimated as $525\pm125$ Myr based on the position of the primary on the colour-magnitude and temperature-luminosity diagrams. Using intermediate-resolution near-infrared spectroscopy, the spectrum of $\zeta$ Del B is shown to be consistent with a mid-L dwarf (L$5\pm2$), at a temperature of $1650\pm200$ K. Combining the measured near-infrared magnitude of $\zeta$ Del B with the estimated temperature leads to a model-dependent mass estimate of $50\pm15$ M$_{\rm Jup}$, corresponding to a mass ratio of $q=0.019\pm0.006$. At a projected separation of $910\pm14$ au, $\zeta$ Del B is among the most widely-separated and extreme-mass ratio substellar companions to a main-sequence star resolved to-date, providing a rare empirical constraint of the formation of low-mass ratio companions at extremely wide separations.
    09/2014; 445(4).
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    ABSTRACT: We have obtained with the LBT Telescope AO system Near-Infrared camera PISCES images of the inner-shell of the nebula around the luminous blue variable star P Cygni in the [Fe II] emission line at 1.6435 {\mu}m. We have combined the images in order to cover a field of view of about 20" around P Cygni thus providing the high resolution (0".08) 2-D spatial distribution of the inner-shell of the P Cygni nebula in [Fe II]. We have identified several nebular emission regions which are characterized by an S/N>3. A comparison of our results with those available in the literature shows full consistency with the finding by Smith & Hartigan (2006) which are based on radial velocity measurements and their relatively good agreement with the extension of emission nebula in [NII] {\lambda}6584 found by Barlow et al. (1994). We have clearly detected extended emission also inside the radial distance R=7".8 and outside R=9".7 which are the nebular boundaries proposed by Smith & Hartigan (2006). New complementary spectroscopic observations to measure radial velocities and to derive the 3-D distribution of P Cygni nebula are planned.
    09/2014;
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    ABSTRACT: We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with ~1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. Our testing employs a single pixel test bench where a novel 2D array architecture is tested. The minimum size of the footprint is dictated by the diameter of the drilled feedhorn aperture. In the adjoining detector block, a 6mm × 6mm footprint houses the SIS mixer, LNA, matching and bias networks, and permanent magnet. We present an initial characterization of the single pixel prototype using a computer controlled test bench to determine Y-factors for a parameter space of LO power, LO frequency, IF bandwidth, magnet field strength, and SIS bias voltage. To reduce the need to replace poorly preforming pixels that are already mounted in a large format array, we show techniques to improve SIS mixer selection prior to mounting in the detector block. The 2D integrated 16-pixel array design has been evolved as we investigate the properties of the single pixel prototype. Carful design of the prototype has allowed for rapid translation of single pixel design improvements to be easily incorporated into the 16-pixel model.
    SPIE Astronomical Telescopes + Instrumentation; 07/2014
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    ABSTRACT: We present new K-band spectroscopy of the UY Aur binary star system. Our data are the first to show H$_{2}$ emission in the spectrum of UY Aur A and the first to spectrally resolve the Br{\gamma} line in the spectrum of UY Aur B. We see an increase in the strength of the Br{\gamma} line in UY Aur A and a decrease in Br{\gamma} and H$_{2}$ line luminosity for UY Aur B compared to previous studies. Converting Br{\gamma} line luminosity to accretion rate, we infer that the accretion rate onto UY Aur A has increased by $2 \times 10^{-9}$ M$_{\odot}$ yr$^{-1}$ per year since a rate of zero was observed in 1994. The Br{\gamma} line strength for UY Aur B has decreased by a factor of 0.54 since 1994, but the K-band flux has increased by 0.9 mags since 1998. The veiling of UY Aur B has also increased significantly. These data evince a much more luminous disk around UY Aur B. If the lower Br{\gamma} luminosity observed in the spectrum of UY Aur B indicates an intrinsically smaller accretion rate onto the star, then UY Aur A now accretes at a higher rate than UY Aur B. However, extinction at small radii or mass pile-up in the circumstellar disk could explain decreased Br{\gamma} emission around UY Aur B even when the disk luminosity implies an increased accretion rate. In addition to our scientific results for the UY Aur system, we discuss a dedicated pipeline we have developed for the reduction of echelle-mode data from the ARIES spectrograph.
    The Astrophysical Journal 07/2014; 792(1). · 6.73 Impact Factor
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    ABSTRACT: We present preliminary results from two parallel programs to search for new substellar companions to nearby, young M-stars and to characterize the atmospheres of known planetary mass and temperature substellar companions. For the M-star survey, we are analyzing high angular resolution archival data on systems within 15pc, complementing a subset with well-determined young ages based on measurements of several age indicators. The results include stellar and substellar companion candidates, which we are currently pursuing with follow-up second epoch images. The characterization component of the project involves using LBT LMIRCam and MMT ARIES direct imaging and spectroscopy data to investigate the atmospheres of known young substellar companions with masses overlapping the planetary regime. These atmospheric studies will represent an analogous comparison to the atmospheres of young imaged planets, and provide a means to fundamentally test evolutionary models, enhancing our understanding of the overall substellar population.
    Proceedings of the International Astronomical Union 06/2014;
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    ABSTRACT: Under the auspices of the NASA Innovative Advanced Concepts (NIAC) Program, the University of Arizona, Southwest Research Institute, Jet Propulsion Laboratory, Arizona State University, and Johns Hopkins Applied Research Laboratory are developing and demonstrating key technologies required to realize a suborbital, 10 meter class telescope suitable for operation from radio to THz frequencies. The telescope consists of an inflatable, half-aluminized spherical reflector deployed within a much larger carrier balloon - either zero pressure or super pressure. Besides serving as a launch vehicle, the carrier balloon provides both a stable mount and radome for the enclosed telescope. Looking up, the LBR will serve as a telescope. Looking down, the LBR can be used for remote sensing or telecommunication activities. The realization of a large, space-based 10 meter class telescope for far-infrared/THz studies has long been a goal of NASA. By combining successful suborbital balloon and ground-based telescope technologies, the dream of a 10 meter class telescope free of 99% of the Earth's atmospheric absorption in the far-infrared can be realized. The same telescope can also be used to perform sensitive, high spectral and spatial resolution limb sounding studies of the Earth's atmosphere in greenhouse gases and serve as a high flying hub for any number of telecommunications and surveillance activities.
    2014 IEEE Aerospace Conference; 03/2014
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    ABSTRACT: We mapped about 1.04deg2 of Serpens Main in the 1213CO (220.4GHz), J=2-1, emission lines (see Figure 1). This study is a continuation of a molecular cloud mapping project with the Arizona Radio Observatory.The observations were made between 2008 November and 2010 June with the Heinrich Hertz Submillimeter Telescope (HHT) on Mt. Graham, AZ, at an elevation of 3200m. The HHT has a 10m diameter paraboloidal dish and observes in the frequency range from 210 to 500GHz.(2 data files).
    01/2014;
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    ABSTRACT: We present spectral line images of [CI] 809 GHz, CO J=1-0 115 GHz and HI 1.4 GHz line emission, and calculate the corresponding C, CO and H column densities, for a sinuous, quiescent Giant Molecular Cloud about 5 kpc distant along the l=328{\deg} sightline (hereafter G328) in our Galaxy. The [CI] data comes from the High Elevation Antarctic Terahertz (HEAT) telescope, a new facility on the summit of the Antarctic plateau where the precipitable water vapor falls to the lowest values found on the surface of the Earth. The CO and HI datasets come from the Mopra and Parkes/ATCA telescopes, respectively. We identify a filamentary molecular cloud, ~75 x 5 pc long with mass ~4 x 10E4 Msun and a narrow velocity emission range of just 4 km/s. The morphology and kinematics of this filament are similar in CO, [CI] and HI, though in the latter appears as self-absorption. We calculate line fluxes and column densities for the three emitting species, which are broadly consistent with a PDR model for a GMC exposed to the average interstellar radiation field. The [C/CO] abundance ratio averaged through the filament is found to be approximately unity. The G328 filament is constrained to be cold (Tdust < 20K) by the lack of far-IR emission, to show no clear signs of star formation, and to only be mildly turbulent from the narrow line width. We suggest that it may represent a GMC shortly after formation, or perhaps still be in the process of formation.
    01/2014; 782(2).
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    ABSTRACT: We mapped 12CO and 13CO J = 2-1 emission over 1.04 square deg of the Serpens molecular cloud with 38 arcsec spatial and 0.3 km/s spectral resolution using the Arizona Radio Observatory Heinrich Hertz Submillimeter telescope. Our maps resolve kinematic properties for the entire Serpens cloud. We also compare our velocity moment maps with known positions of Young Stellar Objects (YSOs) and 1.1 mm continuum emission. We find that 12CO is self-absorbed and 13CO is optically thick in the Serpens core. Outside of the Serpens core, gas appears in filamentary structures having LSR velocities which are blue-shifted by up to 2 km/s relative to the 8 km/s systemic velocity of the Serpens cloud. We show that the known Class I, Flat, and Class II YSOs in the Serpens core most likely formed at the same spatial location and have since drifted apart. The spatial and velocity structure of the 12CO line ratios implies that a detailed 3-dimensional radiative transfer model of the cloud will be necessary for full interpretation of our spectral data. The starless cores region of the cloud is likely to be the next site of star formation in Serpens.
    The Astrophysical Journal Supplement Series 11/2013; 209(2). · 16.24 Impact Factor
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    The Astronomical Journal 08/2013; 146(3):71. · 4.97 Impact Factor
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    ABSTRACT: A set of six debris disk candidates identified with IRAS or WISE excesses were observed at either 350 um or 450 um with the CSO. Five of the targets - HIP 51658, HIP 68160, HIP 73512, HIP 76375, and HIP 112460 - have among the largest measured excess emission from cold dust from IRAS in the 25-100 um bands. Single temperature blackbody fits to the excess dust emission of these sources predict 350-450 um fluxes above 240 mJy. The final target - HIP 73165 - exhibits weak excess emission above the stellar photosphere from WISE measurements at 22 um, indicative of a population of warm circumstellar dust. None of the six targets were detected, with 3 sigma upper limits ranging from 51-239 mJy. These limits are significantly below the expected fluxes from SED fitting. Two potential causes of the null detections were explored - companion stars and contamination. To investigate the possible influence of companion stars, imaging data were analyzed from new AO data from the MMT and archival HST, NIRI, and POSS/2MASS data. The images are sensitive to all stellar companions beyond a radius of 1-94 AU. One target is identified as a binary system, but with a separation too large to impact the disk. While the gravitational effects of a companion do not appear to provide an explanation for the submm upper limits, the majority of the IRAS excess targets show evidence for contaminating sources, based on investigation of higher resolution WISE and archival Spitzer and Herschel images. Finally, the exploratory submm measurements of the WISE excess source suggest that the hot dust present around these targets is not matched by a comparable population of colder, outer dust. More extensive and more sensitive Herschel observations of WISE excess sources will build upon this initial example to further define the characteristics of warm debris disks sources.
    Astronomy and Astrophysics 07/2013; · 5.08 Impact Factor
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    ABSTRACT: We present the first results from a new carbon monoxide (CO) survey of the southern Galactic plane being conducted with the Mopra radio telescope in Australia. The 12CO, 13CO and C18O J=1-0 lines are being mapped over the l = 305-345 deg, b = +/- 0.5 deg portion of the 4th quadrant of the Galaxy, at 35" spatial and 0.1 km/s spectral resolution. The survey is being undertaken with two principal science objectives: (i) to determine where and how molecular clouds are forming in the Galaxy and (ii) to probe the connection between molecular clouds and the "missing" gas inferred from gamma-ray observations. We describe the motivation for the survey, the instrumentation and observing techniques being applied, and the data reduction and analysis methodology. In this paper we present the data from the first degree surveyed, l = 323-324 deg, b = +/- 0.5 deg. We compare the data to the previous CO survey of this region and present metrics quantifying the performance being achieved; the rms sensitivity per 0.1 km/s velocity channel is ~1.5K for 12CO and ~0.7K for the other lines. We also present some results from the region surveyed, including line fluxes, column densities, molecular masses, 12CO/13CO line ratios and 12CO optical depths. We also examine how these quantities vary as a function of distance from the Sun when averaged over the 1 square degree survey area. Approximately 2 x 10E6 MSun of molecular gas is found along the G323 sightline, with an average H2 number density of nH2 ~ 1 cm-3 within the Solar circle. The CO data cubes will be made publicly available as they are published.
    Publications of the Astronomical Society of Australia 07/2013; · 3.12 Impact Factor
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    ABSTRACT: All transiting planet observations are at risk of contamination from nearby, unresolved stars. Blends dilute the transit signal, causing the planet to appear smaller than it really is, or produce a false positive detection when the target star is blended with an eclipsing binary. High spatial resolution adaptive optics images are the best way of resolving undetected contaminants. Here we present companions and detection limits for 12 Kepler candidates, of which 4 have companions within 4 arcsec. One system (KOI 1537) consists of two similar-magnitude stars separated by 0.1 arcsec, while KOI 174 has a companion at 0.5 arcsec. In addition, observations were made of 15 transiting planets that were previously discovered by other surveys. The only companion found within 1 arcsec of a known planet is the previously identified companion to WASP-2b. An additional four systems have companions between 1-4 arcsec: HAT-P-30b (3.7 arcsec, Delta Ks = 2.9), HAT-P-32b (2.9 arcsec, Delta Ks = 3.4), TrES-1b (2.3 arcsec, Delta Ks = 7.7), and WASP-P-33b (1.9 arcsec, Delta Ks = 5.5), some of which have not been reported previously. Depending on the spatial resolution of the transit photometry for these systems, these companion stars may require a reassessment of the planetary parameters derived from transit light curves. For all systems observed, we report the limiting magnitudes of additional objects located 0.1-4 arcsec from the target.
    The Astronomical Journal 05/2013; 146(1). · 4.97 Impact Factor
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    ABSTRACT: Context. The formation of OB-type stars up to (at least) 140 M⊙ can be explained via disk-mediated accretion and in fact growing observational evidence of disk-jet systems is found in high-mass star-forming regions. Aims: With the present observations we wish to investigate at sub-arcsecond resolution the jet structure close to the well studied high-mass protostar IRAS 20126+4104, which is known to be surrounded by a Keplerian disk. Methods: Adaptive optics imaging of the 2.2 μm continuum and H2 and Brγ line emission have been performed with the Large Binocular Telescope, attaining an angular resolution of ~90 mas and an astrometric precision of ~100 mas. Results: While our results are consistent with previous K-band images by other authors, the improved (by a factor ~3) resolution allows us to identify a number of previously unseen features, such as bow shocks spread all over the jet structure. Also, we confirm the existence of a bipolar nebulosity within 1'' from the protostar, prove that the emission from the brightest, SE lobe is mostly due to the H2 line, and resolve its structure. Conclusions: Comparison with other tracers such as masers, thermal molecular line emission, and free-free continuum emission proves that the bipolar nebulosity is indeed tracing the root of the bipolar jet powered by the deeply embedded protostar at the center of the Keplerian disk. Based on observations carried out with the Large Binocular Telescope. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.
    Astronomy and Astrophysics 01/2013; · 5.08 Impact Factor
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    ABSTRACT: While the summit of the Antarctic Plateau has long been expected to harbor the best ground-based sites for terahertz (THz) frequency astronomical investigations, it is only recently that direct observations of exceptional THz atmospheric transmission and stability have been obtained. These observations, in combination with recent technological advancements in astronomical instrumentation and autonomous field platforms, make the recognition and realization of terahertz observatories on the high plateau feasible and timely. Here, we will explore the context of terahertz astronomy in the era of Herschel, and the crucial role that observatories on the Antarctic Plateau can play. We explore the important scientific questions to which observations from this unique environment may be most productively applied. We examine the importance and complementarity of Antarctic THz astronomy in the light of contemporary facilities such as ALMA, CCAT, SOFIA and (U)LDB ballooning. Finally, building from the roots of THz facilities in Antarctica to present efforts, we broadly highlight future facilities that will exploit the unique advantages of the Polar Plateau and provide a meaningful, lasting astrophysical legacy.
    Proceedings of the International Astronomical Union 01/2013; 8(S288):256-263.
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    ABSTRACT: We report the results of a medium-narrowband 2 {mu}m line survey covering 5.8 deg{sup 2} near the Galactic plane. We confirm 11 new field Wolf-Rayet stars along three lines of sight probing the inner Galaxy, demonstrating the capability to uncover distant and highly reddened populations of Galactic wind-borne emission-line stars suffering extinction as high as A{sub V} {approx} 40 and as distant as 9 kpc down to modest magnitude limits of K{sub s} {approx} 12.5. All stars are of subtype WC7-8, with median distance d = 6 kpc and median extinction A{sub K{sub s}} = 2.5. Over the fields surveyed, the density of Wolf-Rayet stars to limiting magnitude K{sub s} {approx} 12.5 was found to be 1.9 deg{sup -2}. We compare this to models which predict their distribution within the Galaxy and find that, even neglecting survey and subtype incompleteness, they consistently underpredict the number of newly discovered stars along the surveyed lines of sight.
    The Astronomical Journal 12/2012; 144(6). · 4.97 Impact Factor
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    ABSTRACT: Supercam is a 345 GHz, 64-pixel heterodyne imaging array for the Heinrich Hertz Submillimeter Telescope (HHSMT). By integrating SIS mixer devices with Low Noise Ampliers (LNAs) in 8 - 1x8 pixel modules, the size needed for the cryostat and the complexity of internal wiring is signicantly reduced. All subsystems including the optics, cryostat, bias system, IF boxes, and spectrometer have been integrated for all 64 pixels. In the spring of 2012, SuperCam was installed on the HHSMT for an engineering run where it underwent system level tests and performed rst light observations. In the fall of 2012 SuperCam will begin a 500 square degree survey of the Galactic Plane in 12CO J=3-2. This large-scale survey will help answer fundamental questions about the formation, physical conditions, and energetics of molecular clouds within the Milky Way. The data set will be available via the web to all interested researchers.
    Proc SPIE 09/2012;
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    ABSTRACT: KAPPa (the Kilopixel Array Pathfinder Project) is developing key technologies to enable the construction of heterodyne focal plane arrays in the terahertz frequency regime with ~1000 pixels. The leap to ~1000 pixels requires solutions to several key technological problems before the construction of such a focal plane is possible. The KAPPa project will develop a small (16-pixel) 2D integrated heterodyne focal plane array for the 660 GHz atmospheric window as a technological pathfinder towards future kilopixel heterodyne focal plane arrays.
    Proc SPIE 09/2012;
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    ABSTRACT: First identied in 2009 as the site with the lowest precipitable water and best terahertz transmission on Earth, Ridge A is located approximately 150 km south of Dome A, Antarctica. To further rene this optimum location prior to deployment in 2012 of a robotic THz observatory, we have modelled the atmospheric transmission as a function of location over a 1,000,000 km square grid using three years of data from the Microwave Humidity Sounder on the NOAA-18 satellite. The modelling identies a broad area of exceptionally low water vapour close to the 4,000 metre elevation contour, reaching below 100 microns for extended periods of time.
    Proc SPIE 09/2012;
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    ABSTRACT: The Adaptive Optics System at the Large Binocular Telescope Observatory consists of two Adaptive Secondary (ASM) mirrors and two Pyramid Wavefront sensors. The first ASM/Pyramid pair has been commissioned and is being used for science operation using the NIR camera PISCES on the right side of the binocular telescope. The left side ASM/Pyramid system is currently being commissioned, with completion scheduled for the Fall of 2012. We will discuss the operation of the first Adaptive Optics System at the LBT Observatory including interactions of the AO system with the telescope and its TCS, observational modes, user interfaces, observational scripting language, time requirement for closed loop and offsets and observing efficiency.
    Proc SPIE 07/2012;

Publication Stats

586 Citations
317.27 Total Impact Points

Institutions

  • 2003–2014
    • The University of Arizona
      • Department of Astronomy
      Tucson, Arizona, United States
    • California Institute of Technology
      Pasadena, California, United States
  • 2012
    • University of Minnesota Duluth
      Duluth, Minnesota, United States
  • 2010
    • Arizona State University
      • School of Earth and Space Exploration
      Phoenix, Arizona, United States
    • National Radio Astronomy Observatory
      Charlottesville, Virginia, United States
  • 2005
    • Honolulu University
      Honolulu, Hawaii, United States