Craig Kulesa

The University of Arizona, Tucson, Arizona, United States

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Publications (147)331.63 Total impact

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    [Show abstract] [Hide abstract] ABSTRACT: We present spectral data cubes of the [CI] 809GHz, 12CO 115GHz, 13CO 110GHz and HI 1.4GHz line emission from an 1 square degree region along the l = 328{\deg} (G328) sightline in the Galactic Plane. Emission arises principally from gas in three spiral arm crossings along the sight line. The distribution of the emission in the CO and [CI] lines is found to be similar, with the [CI] slightly more extended, and both are enveloped in extensive HI. Spectral line ratios per voxel in the data cubes are found to be similar across the entire extent of the Galaxy. However, towards the edges of the molecular clouds the [CI]/13CO and 12CO/13CO line ratios rise by ~50%, and the [CI]/HI ratio falls by ~10$%. We attribute this to these sightlines passing predominantly through the surfaces of photodissociation regions (PDRs), where the carbon is found mainly as C or C+, while the H2 is mostly molecular, and the proportion of atomic gas also increases. We undertake modelling of the PDR emission from low density molecular clouds excited by average interstellar radiation fields and cosmic-ray ionization to quantify this comparison, finding that depletion of sulfur and reduced PAH abundance is needed to match line fluxes and ratios. Roughly one-third of the molecular gas along the sightline is found to be associated with this surface region, where the carbon is largely not to be found in CO. ~10% of the atomic hydrogen along the sightline is cold gas within PDRs.
    Full-text · Article · Aug 2015 · The Astrophysical Journal
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    [Show abstract] [Hide abstract] ABSTRACT: We present deep near-infrared (NIR) J, Ks photometry of the old, metal-poor Galactic globular cluster M\,15 obtained with images collected with the LUCI1 and PISCES cameras available at the Large Binocular Telescope (LBT). We show how the use of First Light Adaptive Optics system coupled with the (FLAO) PISCES camera allows us to improve the limiting magnitude by ~2 mag in Ks. By analyzing archival HST data, we demonstrate that the quality of the LBT/PISCES color magnitude diagram is fully comparable with analogous space-based data. The smaller field of view is balanced by the shorter exposure time required to reach a similar photometric limit. We investigated the absolute age of M\,15 by means of two methods: i) by determining the age from the position of the main sequence turn-off; and ii) by the magnitude difference between the MSTO and the well-defined knee detected along the faint portion of the MS. We derive consistent values of the absolute age of M15, that is 12.9+-2.6 Gyr and 13.3+-1.1 Gyr, respectively.
    Full-text · Article · Jul 2015 · The Astrophysical Journal
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    [Show abstract] [Hide abstract] ABSTRACT: Context. We present a study of the complex high-mass star forming region IRAS 05137+3919 (also known as Mol8), where multiple jets and a rich stellar cluster have been described in previous works. Aims. Our goal is to determine the number of jets and shed light on their origin, and thus determine the nature of the young stars powering these jets. We also wish to analyse the stellar clusters by resolving the brightest group of stars. Methods. The star forming region was observed in various tracers and the results were complemented with ancillary archival data. The new data represent a substantial improvement over previous studies both in resolution and frequency coverage. In particular, adaptive optics provides us with an angular resolution of 80 mas in the near IR, while new mid- and far-IR data allow us to sample the peak of the spectral energy distribution and thus reliably estimate the bolometric luminosity. Results. Thanks to the near-IR continuum and millimetre line data we can determine the structure and velocity field of the bipolar jets and outflows in this star forming region. We also find that the stars are grouped into three clusters and the jets originate in the richest of these, whose luminosity is ~ 2.4 × 104L Interestingly, our high-resolution near-IR images allow us to resolve one of the two brightest stars (A and B) of the cluster into a double source (A1+A2). Conclusions. We confirm that there are two jets and establish that they are powered by B-type stars belonging to cluster C1. On this basis and on morphological and kinematical arguments, we conclude that the less extended jet is almost perpendicular to the line of sight and that it originates in the brightest star of the cluster, while the more extended one appears to be associated with the more extincted, double source A1+A2. We propose that this is not a binary system, but a small bipolar reflection nebula at the root of the large-scale jet, outlining a still undetected circumstellar disk. The gas kinematics on a scale of ~0.2 pc seems to support our hypothesis, because it appears to trace rotation about the axis of the associated jet.
    Full-text · Article · Jul 2015 · Astronomy and Astrophysics
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    [Show abstract] [Hide abstract] ABSTRACT: We present a large-scale, volume-limited companion survey of 245 late-K to mid-M (K7-M6) dwarfs within 15 pc. Infrared adaptive optics (AO) data were analysed from the Very Large Telescope, Subaru Telescope, Canada–France–Hawaii Telescope, and MMT Observatory to detect close companions to the sample from ∼ 1 to 100 au, while digitized wide-field archival plates were searched for wide companions from ∼ 100 to 10 000 au. With sensitivity to the bottom of the main sequence over a separation range of 3 to 10 000 au, multiple AO and wide-field epochs allow us to confirm candidates with common proper motions, minimize background contamination, and enable a measurement of comprehensive binary statistics. We detected 65 comoving stellar companions and find a companion star fraction of 23.5 ± 3.2 per cent over the 3 au to 10 000 au separation range. The companion separation distribution is observed to rise to a higher frequency at smaller separations, peaking at closer separations than measured for more massive primaries. The mass ratio distribution across the q = 0.2–1.0 range is flat, similar to that of multiple systems with solar-type primaries. The characterization of binary and multiple star frequency for low-mass field stars can provide crucial comparisons with star-forming environments and hold implications for the frequency and evolutionary histories of their associated discs and planets.
    Full-text · Article · Mar 2015 · Monthly Notices of the Royal Astronomical Society
  • [Show abstract] [Hide abstract] ABSTRACT: We present observations of the first 10° of longitude in the Mopra CO survey of the southern Galactic plane, covering Galactic longitude l = 320-330° and latitude b = ±0.5°, and l = 327-330°, b = +0.5-1.0°. These data have been taken at 35-arcsec spatial resolution and 0.1 km s−1 spectral resolution, providing an unprecedented view of the molecular clouds and gas of the southern Galactic plane in the 109-115 GHz J = 1-0 transitions of 12CO, 13CO, C18O, and C17O. Together with information about the noise statistics from the Mopra telescope, these data can be retrieved from the Mopra CO website and the CSIRO-ATNF data archive.
    No preview · Article · Feb 2015 · Publications of the Astronomical Society of Australia
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    [Show abstract] [Hide abstract] ABSTRACT: We report the discovery of a wide comoving substellar companion to the nearby (D = 67.5 ± 1.1 pc) A3V star ζ Delphini based on imaging and follow-up spectroscopic observations obtained during the course of our Volume-limited A-Star (VAST) multiplicity survey. ζ 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 ζ Del system was estimated as 525 ± 125 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 ζ Del B is shown to be consistent with a mid-L dwarf (L5 ± 2), at a temperature of 1650 ± 200 K. Combining the measured near-infrared magnitude of ζ Del B with the estimated temperature leads to a model-dependent mass estimate of 50 ± 15 MJup, corresponding to a mass ratio of q = 0.019 ± 0.006. At a projected separation of 910 ± 14 au, ζ 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.
    Full-text · Article · Sep 2014 · Monthly Notices of the Royal Astronomical Society
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    [Show abstract] [Hide abstract] ABSTRACT: Using the adaptive optics system of the Large Binocular Telescope, we have obtained 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 μm. We have combined the images in order to cover a field of view of about 20 arcsec around P Cygni, thus providing the high-resolution (0.08 arcsec) two-dimensional spatial distribution of the inner shell of the P Cygni nebula in [Fe ii]. We have identified several nebular emission regions that are characterized by a signal-to-noise ratio > 3. A comparison of our results with those available in the literature shows full consistency with the findings of Smith & Hartigan, which are based on radial velocity measurements, and relatively good agreement with the extension of emission nebula in [N ii] λ6584 found by Barlow et al. We have clearly also detected extended emission inside the radial distance R = 7.8 arcsec and outside R = 9.7 arcsec, which are the nebular boundaries proposed by Smith & Hartigan. New complementary spectroscopic observations are planned in order to measure radial velocities and to derive the three-dimensional distribution of the P Cygni nebula.
    Full-text · Article · Sep 2014 · Monthly Notices of the Royal Astronomical Society
  • [Show abstract] [Hide abstract] 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.
    No preview · Conference Paper · Jul 2014
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    [Show abstract] [Hide abstract] 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.
    Preview · Article · Jul 2014 · The Astrophysical Journal
  • [Show abstract] [Hide abstract] 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.
    No preview · Article · Jun 2014 · Proceedings of the International Astronomical Union
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    [Show abstract] [Hide abstract] 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.
    Full-text · Conference Paper · Mar 2014
  • [Show abstract] [Hide abstract] 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).
    No preview · Article · Jan 2014
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    [Show abstract] [Hide abstract] 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.
    Full-text · Article · Jan 2014 · The Astrophysical Journal
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    [Show abstract] [Hide abstract] 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.
    Preview · Article · Nov 2013 · The Astrophysical Journal Supplement Series
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    [Show abstract] [Hide abstract] ABSTRACT: All transiting planets are at risk of contamination by blends with 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 eclipsing binary stars. This paper reports on high spatial-resolution adaptive optics images of 90 Kepler planetary candidates. Companion stars are detected as close as 0ˮ1 from the target star. Images were taken in the near-infrared (J and Ks bands) with ARIES on the MMT and PHARO on the Palomar Hale 200 inch telescope. Most objects (60%) have at least one star within 6" separation and a magnitude difference of 9. Eighteen objects (20%) have at least one companion within 2" of the target star; six companions (7%) are closer than 0ˮ5. Most of these companions were previously unknown, and the associated planetary candidates should receive additional scrutiny. Limits are placed on the presence of additional companions for every system observed, which can be used to validate planets statistically using the BLENDER method. Validation is particularly critical for low-mass, potentially Earth-like worlds, which are not detectable with current-generation radial velocity techniques. High-resolution images are thus a crucial component of any transit follow-up program.
    Full-text · Article · Aug 2013 · The Astronomical Journal
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    [Show abstract] [Hide abstract] 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.
    Full-text · Article · Aug 2013 · Proceedings of the International Astronomical Union
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    [Show abstract] [Hide abstract] 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.
    Full-text · Article · Jul 2013 · Astronomy and Astrophysics
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    [Show abstract] [Hide abstract] ABSTRACT: We present observations of the first ten degrees of longitude in the Mopra carbon monoxide (CO) survey of the southern Galactic plane (Burton et al. 2013), covering Galactic longitude l = 320-330{\deg} and latitude b = $\pm$0.5{\deg}, and l = 327-330{\deg}, b = +0.5-1.0{\deg}. These data have been taken at 35 arc sec spatial resolution and 0.1 km/s spectral resolution, providing an unprecedented view of the molecular clouds and gas of the southern Galactic plane in the 109-115 GHz J = 1-0 transitions of 12CO, 13CO, C18O and C17O. Together with information about the noise statistics from the Mopra telescope, these data can be retrieved from the Mopra CO website and the CSIRO-ATNF data archive.
    Full-text · Article · Jul 2013 · Publications of the Astronomical Society of Australia
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    [Show abstract] [Hide abstract] 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.
    Full-text · Article · May 2013 · The Astronomical Journal
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    [Show abstract] [Hide abstract] ABSTRACT: We have performed H and K-S band observations of the planetary system around HR 8799 using the new AO system at the Large Binocular Telescope and the PISCES Camera. The excellent instrument performance (Strehl ratios up to 80% in H band) enabled the detection of the innermost planet, HR 8799e, at H band for the first time. The H and K-S magnitudes of HR 8799e are similar to those of planets c and d, with planet e being slightly brighter. Therefore, HR 8799e is likely slightly more massive than c and d. We also explored possible orbital configurations and their orbital stability. We confirm that the orbits of planets b, c and e are consistent with being circular and coplanar; planet d should have either an orbital eccentricity of about 0.1 or be non-coplanar with respect to b and c. Planet e can not be in circular and coplanar orbit in a 4:2:1 mean motion resonances with c and d, while coplanar and circular orbits are allowed for a 5:2 resonance. The analysis of dynamical stability shows that the system is highly unstable or chaotic when planetary masses of about 5 M-J for b and 7 M-J for the other planets are adopted. Significant regions of dynamical stability for timescales of tens of Myr are found when adopting planetary masses of about 3.5, 5, 5, and 5 M-J for HR 8799b, c, d, and e respectively. These masses are below the current estimates based on the stellar age (30 Myr) and theoretical models of substellar objects.
    Full-text · Article · Jan 2013 · Astronomy and Astrophysics