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2011

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Articles 181 - 210 of 354

Full-Text Articles in Astrophysics and Astronomy

Measurement Of Neutron Reflectivity From A Silicon Crystal: Preparation For An Nmdm Measurement, Benjamin Barber Apr 2011

Measurement Of Neutron Reflectivity From A Silicon Crystal: Preparation For An Nmdm Measurement, Benjamin Barber

Symposium on Research and Creative Expression (SORCE)

Physicists from Argonne National Laboratories, Valparaiso University, the University of Hawaii, and the National Institute for Standards and Technology have designed an experiment to use the known neutron magnetic dipole moment (nMDM) to measure Schwinger scattering in silicon (Si), a process whereby the orientation of the magnetic dipole polarization is altered by interactions with the atomic electric fields in a Si crystal. This measurement is intended to be a precursor to a search for a neutron electric dipole moment (nEDM) employing a similar spin rotation via a different interaction. Both measurements depend on neutron Bragg reflections down a slotted Si …

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An Observational Study Of Variable Stars, Joel Rogers, Wesley Cheek Apr 2011

An Observational Study Of Variable Stars, Joel Rogers, Wesley Cheek

Symposium on Research and Creative Expression (SORCE)

This past summer, we carried out an observational study of light variability in approximately 20 stars.  Our goal was to document their changes in brightness, determine a period of the variability, and investigate whether their brightness changes were correlated with changes in color (and thus temperature). These stars are part of a special class of stars that have evolved beyond the red giant phase but have not yet become white dwarfs.  Little is known about their variability during this phase.  We observed them on almost every clear night during the summer of 2010.  We then compared the data for this …

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Nonadiabatic Generation Of A Pure Spin Current In A One-Dimensional Quantum Ring With Spin-Orbit Interaction, Marian Nita, D C. Marinescu, Andrei Manolescu, Vidar Gudmundsson Apr 2011

Nonadiabatic Generation Of A Pure Spin Current In A One-Dimensional Quantum Ring With Spin-Orbit Interaction, Marian Nita, D C. Marinescu, Andrei Manolescu, Vidar Gudmundsson

Publications

We demonstrate the theoretical possibility of obtaining a pure spin current in a 1D ring with spin-orbit interaction by irradiation with a nonadiabatic, two-component terahertz laser pulse, whose spatial asymmetry is reflected by an internal phase difference φ. The solutions of the equation of motion for the density operator are obtained for a spin-orbit coupling linear in the electron momentum (Rashba) and they are used to calculate the time-dependent charge and spin currents. We find that there are critical values of φ at which the charge current disappears, while the spin current reaches a maximum or a minimum value.

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Oral Presentation: The Universe In A Box, Jason Jaacks Apr 2011

Oral Presentation: The Universe In A Box, Jason Jaacks

Festival of Communities: UG Symposium (Posters)

When and how galaxies formed throughout the history of the Universe is one of the most fundamental questions of astronomy and astrophysics. As technology improves, astronomers are able to push the frontier of galaxy observation to a period when the Universe was less than 1 billion years old. This is when the first galaxies are beginning to form. However, beyond the limits of observational technology lies data fundamental to our complete understanding of these processes. Using state-of-the-art cosmological hydrodynamic computer codes combined with access to the nation’s largest and fastest supercomputers, we are able to simulate the formation and evolution …

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Serpentinite Weathering And Implications For Mars, Valerie Tu, Julie Baumeister, Rodney Metcalf, A. Olsen, Elisabeth Hausrath Apr 2011

Serpentinite Weathering And Implications For Mars, Valerie Tu, Julie Baumeister, Rodney Metcalf, A. Olsen, Elisabeth Hausrath

Festival of Communities: UG Symposium (Posters)

In the search for life on Mars near-surface soil environments may be important habitats for life accessible to future missions. Serpentinite rocks have been documented on Mars, as well as other clay minerals including smectite and kaolinites. Previous studies of soils formed on serpentinites on Earth have documented the formation of extensive clays. Serpentinites are additionally of interest as habitats for life such as methanogens. Here we examine weathering of serpentinites from bedrock to soil surface, as a potential route for the formation of clay minerals on Mars from abundant ultramafic minerals. We additionally test for the presence of Fe-oxidizing …

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Halo Occupation Of Lyman-Break Galaxies, Saju Varghese, Ken Nagamine, Jason Jaacks, Jun-Hwan Choi Apr 2011

Halo Occupation Of Lyman-Break Galaxies, Saju Varghese, Ken Nagamine, Jason Jaacks, Jun-Hwan Choi

Festival of Communities: UG Symposium (Posters)

Lyman-break galaxies (LBGs) are star-forming galaxies found at high redshift that provide large amounts of information on early star and galaxy formation. We use large-scale cosmological smoothed-particle hydrodynamical simulations to simulate the physical properties of LBGs, such as stellar mass, star-formation rate, and magnitude. In particular, we focus on the question of which dark matter (DM) halos host LBGs. Our simulation suggests that only 1.74% of all DM halos host LBGs, though among the massive DM halos with mass Mhalo >1011.5 Msun, the fraction is 51.93%. The occupation number of LBGs ranges from 1 to 17 per halo.

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Detection Of Ch+ Emission From The Disc Around Hd 100546, W F. Thi, F Menard, G Meeus, C. Martin-Zaidi, P Woitke, E Tatulli, M Benisty, I Kamp, I Pascucci, C Pinte, C A. Grady, Sean D. Brittain, G J. White, C D. Howard, G Sandell, C Eiroa Apr 2011

Detection Of Ch+ Emission From The Disc Around Hd 100546, W F. Thi, F Menard, G Meeus, C. Martin-Zaidi, P Woitke, E Tatulli, M Benisty, I Kamp, I Pascucci, C Pinte, C A. Grady, Sean D. Brittain, G J. White, C D. Howard, G Sandell, C Eiroa

Publications

Despite its importance in the thermal balance of the gas and in the determination of primeval planetary atmospheres, the chemistry in protoplanetary discs remains poorly constrained with only a handful of detected species. We observed the emission from the disc around the Herbig Be star HD 100546 with the PACS instrument in the spectroscopic mode on board the Herschel Space Telescope as part of the GAS in Protoplanetary Systems (GASPS) programme and used archival data from the DIGIT programme to search for the rotational emission of CH+. We detected in both datasets an emission line centred at 72.16 μm that …

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Pulsar Timing Sensitivity To Very-Low-Frequency Gravitational Waves, Fredrick A. Jenet, J. W. Armstrong, Massimo Tinto Apr 2011

Pulsar Timing Sensitivity To Very-Low-Frequency Gravitational Waves, Fredrick A. Jenet, J. W. Armstrong, Massimo Tinto

Physics & Astronomy Faculty Publications

We compute the sensitivity, constrained by instrumental, propagation, and other fundamental noises, of pulsar timing to very-low-frequency gravitational waves (GWs). Reaching predicted GW signal strengths will require suppression of time-of-arrival fluctuations caused by interstellar plasma turbulence and a reduction of white rms timing noise to ≲100  ns. Assuming negligible intrinsic pulsar rotational noise, perfect time transfer from time standard to observatory, and stable pulse profiles, the resulting single-pulsar signal-to-noise ratio=1 sensitivity is limited by terrestrial time standards at ℎrms∼2×10−16  [f/(1  cycle/year)]−1/2 for 𝑓<3×10−8  Hz, where f is the Fourier frequency and a bandwidth of 1 cycle/(10 years) is assumed. Since this sensitivity is comparable to predicted GW signal levels, a reliable detection will require substantial signal-to-noise ratio improvement via pulsar timing array.

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Efficient Decomposition Of Cosmic Microwave Background Polarization Maps Into Pure E, Pure B, And Ambiguous Components., Emory F. Bunn Apr 2011

Efficient Decomposition Of Cosmic Microwave Background Polarization Maps Into Pure E, Pure B, And Ambiguous Components., Emory F. Bunn

Physics Faculty Publications

Separation of the B component of a cosmic microwave background (CMB) polarization map from the much larger E component is an essential step in CMB polarimetry. For a map with incomplete sky coverage, this separation is necessarily hampered by the presence of ambiguous modes which could be either E or B modes. I present an efficient pixel-space algorithm for removing the ambiguous modes and separating the map into pure E and B components. The method, which works for arbitrary geometries, does not involve generating a complete basis of such modes and scales the cube of the number of pixels on …

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The Efficacy Of Galaxy Shape Parameters In Photometric Redshift Estimation: A Neural Network Approach, Jack Singal, M. Shmakova, B. Gerke, R. L. Griffith, J. Lotz Apr 2011

The Efficacy Of Galaxy Shape Parameters In Photometric Redshift Estimation: A Neural Network Approach, Jack Singal, M. Shmakova, B. Gerke, R. L. Griffith, J. Lotz

Physics Faculty Publications

We present a determination of the effects of including galaxy morphological parameters in photometric redshift estimation with an artificial neural network method. Neural networks, which recognize patterns in the information content of data in an unbiased way, can be a useful estimator of the additional information contained in extra parameters, such as those describing morphology, if the input data are treated on an equal footing. We use imaging and five band photometric magnitudes from the All-wavelength Extended Groth Strip International Survey. It is shown that certain principal components of the morphology information are correlated with galaxy type. However, we find …

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Cross-Correlation Of Cosmological Birefringence With Cmb Temperature, Robert R. Caldwell, Vera Gluscevic, Marc Kamionkowski Apr 2011

Cross-Correlation Of Cosmological Birefringence With Cmb Temperature, Robert R. Caldwell, Vera Gluscevic, Marc Kamionkowski

Dartmouth Scholarship

Theories for new particle and early-Universe physics abound with pseudo-Nambu-Goldstone fields that arise when global symmetries are spontaneously broken. The coupling of these fields to the Chern-Simons term of electromagnetism may give rise to cosmological birefringence (CB), a frequency-independent rotation of the linear polarization of photons as they propagate over cosmological distances. Inhomogeneities in the CB-inducing field may yield a rotation angle that varies across the sky. Here we note that such a spatially-varying birefringence may be correlated with the cosmic microwave background (CMB) temperature. We describe quintessence scenarios where this cross-correlation exists and other scenarios where the scalar field …

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Ozone Profile Observations In Houston, Texas (1994 - 2010) From Aircraft, Balloons, And Satellites, Gary A. Morris, Barry Lefer, Bernhard Rappenglueck, Christine Haman, Christopher Boxe, Scott Hersey, Valerie Thouret, Jean-Pierre Cammas, Bryan Johnson, Samuel Oltmans Apr 2011

Ozone Profile Observations In Houston, Texas (1994 - 2010) From Aircraft, Balloons, And Satellites, Gary A. Morris, Barry Lefer, Bernhard Rappenglueck, Christine Haman, Christopher Boxe, Scott Hersey, Valerie Thouret, Jean-Pierre Cammas, Bryan Johnson, Samuel Oltmans

Physics and Astronomy Faculty Presentations

Houston, Texas has long been an urban area plagued with high levels of surface ozone, particularly in spring and late summer. The combination of a large commuter population and one of the largest concentrations of petrochemical plants in the world results in abundant and nearly co-located sources of NOx and hydrocarbons. The location of Houston on the South Coast of the United States in a subtropical climate results in meteorological conditions that favor ozone production. Using MOZAIC (1994 - 2004), ozonesonde (2000, 2004 - 2010), and TES (2005 – 2010) data, we examine the evolution of ozone profiles over Houston …

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Astr 404 Apr 2011

Astr 404

Department of Physics and Astronomy: Syllabi

No abstract provided.

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Grounded, In High Orbit: Undergraduate Space Research At The University Of New Hampshire, George Clark, Morgan O’Neill Apr 2011

Grounded, In High Orbit: Undergraduate Space Research At The University Of New Hampshire, George Clark, Morgan O’Neill

Inquiry Journal 2011

No abstract provided.

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Thermodynamics Of The Antiferromagnetic Heisenberg Model On The Checkerboard Lattice, Ehsan Khatami, Maros Rigol Apr 2011

Thermodynamics Of The Antiferromagnetic Heisenberg Model On The Checkerboard Lattice, Ehsan Khatami, Maros Rigol

Faculty Publications

Employing numerical linked-cluster expansions (NLCEs) along with exact diagonalizations of finite clusters with periodic boundary condition, we study the energy, specific heat, entropy, and various susceptibilities of the antiferromagnetic Heisenberg model on the checkerboard lattice. NLCEs, combined with extrapolation techniques, allow us to access temperatures much lower than those accessible to exact diagonalization and other series expansions. We show that the high-temperature peak in specific heat decreases as the frustration increases, consistent with the large amount of unquenched entropy in the region around maximum classical frustration, where the nearest-neighbor and next-nearest-neighbor exchange interactions (J and J′, respectively) have the same …

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V474 Car: A Rare Halo Rs Cvn Binary In Retrograde Galactic Orbit, E. J. Bubar, E. E. Mamajek, Eric L.N. Jensen, F. M. Walter Apr 2011

V474 Car: A Rare Halo Rs Cvn Binary In Retrograde Galactic Orbit, E. J. Bubar, E. E. Mamajek, Eric L.N. Jensen, F. M. Walter

Physics & Astronomy Faculty Works

We report the discovery that the star V474 Car is an extremely active, high velocity halo RS CVn system. The star was originally identified as a possible pre-main-sequence star in Carina, given its enhanced stellar activity, rapid rotation (10.3 days), enhanced Li, and absolute magnitude which places it above the main sequence (MS). However, its extreme radial velocity (264 km s–1) suggested that this system was unlike any previously known pre-MS system. Our detailed spectroscopic analysis of echelle spectra taken with the CTIO 4 m finds that V474 Car is both a spectroscopic binary with an orbital period …

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Astr 403 Apr 2011

Astr 403

Department of Physics and Astronomy: Syllabi

No abstract provided.

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Further X-Ray Observations Of Exo 0748-676 In Quiescence: Evidence For A Cooling Neutron Star Crust, N. Degenaar, M. T. Wolff, P. S. Ray, K. S. Wood, J. Homan, W. H. G. Lewin, P. G. Jonker, E. M. Cackett, J. M. Miller, E. F. Brown, R. Wijnands Apr 2011

Further X-Ray Observations Of Exo 0748-676 In Quiescence: Evidence For A Cooling Neutron Star Crust, N. Degenaar, M. T. Wolff, P. S. Ray, K. S. Wood, J. Homan, W. H. G. Lewin, P. G. Jonker, E. M. Cackett, J. M. Miller, E. F. Brown, R. Wijnands

Physics and Astronomy Faculty Research Publications

In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 started a transition from outburst to quiescence, after it actively accreted for more than 24 yr. In a previous work, we discussed Chandra and Swift observations obtained during the first 5 months of this transition. Here, we report on further X-ray observations of EXO 0748-676, extending the quiescent monitoring to 1.6 yr. Chandra and XMM-Newton data reveal quiescent X-ray spectra composed of a soft, thermal component that is well fitted by a neutron star atmosphere model. An additional hard power-law tail is detected that changes non-monotonically …

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A Fast X-Ray Disk Wind In The Transient Pulsar Igr J17480-2446 In Terzan 5, Jon M. Miller, Dipankar Maitra, Edward M. Cackett, Sudip Bhattacharyya, Tod E. Strohmayer Apr 2011

A Fast X-Ray Disk Wind In The Transient Pulsar Igr J17480-2446 In Terzan 5, Jon M. Miller, Dipankar Maitra, Edward M. Cackett, Sudip Bhattacharyya, Tod E. Strohmayer

Physics and Astronomy Faculty Research Publications

Accretion disk winds are revealed in Chandra gratings spectra of black holes. The winds are hot and highly ionized (typically composed of He-like and H-like charge states) and show modest blueshifts. Similar line spectra are sometimes seen in "dipping" low-mass X-ray binaries (LMXBs), which are likely viewed edge-on; however, that absorption is tied to structures in the outer disk, and blueshifts are not typically observed. Here, we report the detection of blueshifted He-like Fe XXV (3100 ± 400 km s-1) and H-like Fe XXVI (1000 ± 200 km s-1) absorption lines in a Chandra/HETG spectrum of …

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Characterizing The Iyj Excess Continuum Emission In T Tauri Stars, William J. Fischer, Suzan Edwards, Lynne A. Hillenbrand, John Kwan Apr 2011

Characterizing The Iyj Excess Continuum Emission In T Tauri Stars, William J. Fischer, Suzan Edwards, Lynne A. Hillenbrand, John Kwan

Astronomy: Faculty Publications

We present the first characterization of the excess continuum emission of accreting T Tauri stars between optical and near-infrared wavelengths. With nearly simultaneous spectra from 0.48 to 2.4μm acquired with HIRES and NIRSPEC on Keck and SpeX on the Infrared Telescope Facility, we find significant excess continuum emission throughout this region, including the I, Y, and J bands, which are usually thought to diagnose primarily photospheric emission. The IYJ excess correlates with the excess in the V band, attributed to accretion shocks in the photosphere, and the excess in the K band, attributed to dust in the inner …

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Astr 404: Stellar Astrophysics, Edward Schmidt Apr 2011

Astr 404: Stellar Astrophysics, Edward Schmidt

Department of Physics and Astronomy: Syllabi

Syllabus for ASTR 404: Stellar Astrophysics for Spring 2011 semester.

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Photon Reconstruction In The Atlas Inner Detector And Liquid Argon Barrel Calorimeter At The 2004 Combined Test Beam, E. Abat, J. M. Abdallah, T. N. Addy, P. Adragna, M. Aharrouche, A. Ahmad, T. P. Akesson, M. Aleksa, C. Alexa, K. Anderson, A. Andreazza, F. Anghinolf, A. Antonaki, G. Arabidze, E. Arik, T. Atkinson, J. Baines, O. K. Baker, D. Banfi, S. Baron, Roberto Petti, Et. Al. Apr 2011

Photon Reconstruction In The Atlas Inner Detector And Liquid Argon Barrel Calorimeter At The 2004 Combined Test Beam, E. Abat, J. M. Abdallah, T. N. Addy, P. Adragna, M. Aharrouche, A. Ahmad, T. P. Akesson, M. Aleksa, C. Alexa, K. Anderson, A. Andreazza, F. Anghinolf, A. Antonaki, G. Arabidze, E. Arik, T. Atkinson, J. Baines, O. K. Baker, D. Banfi, S. Baron, Roberto Petti, Et. Al.

Faculty Publications

The reconstruction of photons in the ATLAS detector is studied with data taken during the 2004 Combined Test Beam, where a full slice of the ATLAS detector was exposed to beams of particles of known energy at the CERN SPS. The results presented show significant differences in the longitudinal development of the electromagnetic shower between converted and unconverted photons as well as in the total measured energy. The potential to use the reconstructed converted photons as a means to precisely map the material of the tracker in front of the electromagnetic calorimeter is also considered. All results obtained are compared …

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Section Abstracts: Astronomy, Mathematics And Physics With Materials Science Apr 2011

Section Abstracts: Astronomy, Mathematics And Physics With Materials Science

Virginia Journal of Science

Abstracts for the Astronomy, Mathematics, and Physics with Materials Science Section for the 89th Annual Meeting of the Virginia Academy of Science, May 25-27, 2011, University of Richmond, Richmond VA.

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Recalibrating The Star Sensor: From The Ibex Satellite To The Renu Rocket, Joshua French Apr 2011

Recalibrating The Star Sensor: From The Ibex Satellite To The Renu Rocket, Joshua French

Inquiry Journal 2011

No abstract provided.

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The Arcade 2 Instrument, Jack Singal, D. J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, T. Villela, E. Wollack, C. A. Wuensche Apr 2011

The Arcade 2 Instrument, Jack Singal, D. J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, T. Villela, E. Wollack, C. A. Wuensche

Physics Faculty Publications

The second generation Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE 2) instrument is a balloon-borne experiment to measure the radiometric temperature of the cosmic microwave background and Galactic and extragalactic emission at six frequencies from 3 to 90 GHz. ARCADE 2 utilizes a double-nulled design where emission from the sky is compared to that from an external cryogenic full-aperture blackbody calibrator by cryogenic switching radiometers containing internal blackbody reference loads. In order to further minimize sources of systematic error, ARCADE 2 features a cold fully open aperture with all radiometrically active components maintained at near 2.7 K without …

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A Three Dimensional Green's Function Solution Technique For The Transport Of Heavy Ions In Laboratory And Space, Candice Rockell Gerstner Apr 2011

A Three Dimensional Green's Function Solution Technique For The Transport Of Heavy Ions In Laboratory And Space, Candice Rockell Gerstner

Mathematics & Statistics Theses & Dissertations

In the future, astronauts will be sent into space for longer durations of time compared to previous missions. The increased risk of exposure to ionizing radiation, such as Galactic Cosmic Rays and Solar Particle Events, is of great concern. Consequently, steps must be taken to ensure astronaut safety by providing adequate shielding. The shielding and exposure of space travelers is controlled by the transport properties of the radiation through the spacecraft, its onboard systems and the bodies of the individuals themselves. Meeting the challenge of future space programs will therefore require accurate and efficient methods for performing radiation transport calculations …

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The Chromospheric Activity, Age, Metallicity, And Space Motions Of 36 Wide Binaries, Jingkun Zhao, Terry D. Oswalt, Mark J. Rudkin, Gang Zhao, Yuqin Chen Apr 2011

The Chromospheric Activity, Age, Metallicity, And Space Motions Of 36 Wide Binaries, Jingkun Zhao, Terry D. Oswalt, Mark J. Rudkin, Gang Zhao, Yuqin Chen

Aerospace, Physics, and Space Science Faculty Publications

We present the chromospheric activity (CA) levels, metallicities, and full space motions for 41 F, G, K, and M dwarf stars in 36 wide binary systems. Thirty-one of the binaries contain a white dwarf (WD) component. In such binaries, the total age can be estimated by adding the cooling age of the WD to an estimate of the progenitor's main-sequence lifetime. To better understand how CA correlates to stellar age, 14 cluster member stars were also observed. Our observations demonstrate for the first time that, in general, CA decays with age from 50 Myr to at least 8 Gyr for …

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Polymer Molded Templates For Nanostructured Amorphous Silicon Photovoltaics, Lei Pei, Amy Balls, Cary Tippets, Jonathan Abbott, Matthew R. Linford, David D. Allred, Richard R. Vanfleet, Robert C. Davis, Jian Hu, Arun Madan Apr 2011

Polymer Molded Templates For Nanostructured Amorphous Silicon Photovoltaics, Lei Pei, Amy Balls, Cary Tippets, Jonathan Abbott, Matthew R. Linford, David D. Allred, Richard R. Vanfleet, Robert C. Davis, Jian Hu, Arun Madan

Faculty Publications

Here, the authors report the fabrication of transparent polymer templates for nanostructured amorphous silicon photovoltaics using low-cost nanoimprint lithography of polydimethylsiloxane. The template contains a square two-dimensional array of high-aspect-ratio nanoholes (300 nm diameter by 1 µm deep holes) on a 500X500 nm^2 pitch. A 100 nm thick layer of a-Si:H was deposited on the template surface resulting in a periodically nanostructured film. The optical characterization of the nanopatterned film showed lower light transmission at 600-850 nm wavelengths and lower light reflection at 400-650 nm wavelengths, resulting in 20% higher optical absorbance at AM 1.5 spectral irradiance versus a nonpatterned …

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Cluster Observations Of A Cusp Diamagnetic Cavity: Structure, Size, And Dynamics, K. Nykyri, A. Otto, E. Adamson, E. Dougal, J. Mumme Mar 2011

Cluster Observations Of A Cusp Diamagnetic Cavity: Structure, Size, And Dynamics, K. Nykyri, A. Otto, E. Adamson, E. Dougal, J. Mumme

Publications

We have analyzed Cluster magnetic field and plasma data during high‐altitude cusp crossing and compared them with high‐resolution MHD simulations. Cluster encountered a diamagnetic cavity (DMC) during northward interplanetary magnetic field (IMF) conditions, and as the IMF rotated southward, the spacecraft reencountered the cavity more at the sunward side of the cusp because the reconnection site had changed location. We found evidence of magnetic reconnection both during northward and southward IMF conditions. The Cluster separation was ∼5000 km, enabling for the first time measurements both inside the DMC and surrounding boundaries that allowed us to construct the structure of the …

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Water Depletion In The Disk Atmosphere Of Herbig Aebe Stars, D Fedele, I Pascucci, Sean D. Brittain, I Kamp, P Woitke, J P. Williams, W.R.F. Dent, W F. Thi Mar 2011

Water Depletion In The Disk Atmosphere Of Herbig Aebe Stars, D Fedele, I Pascucci, Sean D. Brittain, I Kamp, P Woitke, J P. Williams, W.R.F. Dent, W F. Thi

Publications

We present high-resolution (R ∼ 100,000) L-band spectroscopy of 11 Herbig AeBe stars with circumstellar disks. The observations were obtained with the VLT/CRIRES to detect hot water and hydroxyl radical emission linespreviously detected in disks around T Tauri stars. OH emission lines are detected toward four disks. The OH 2Π3/2 P4.5 (1+,1−) doublet is spectrally resolved as well as the velocity profile of each component of the doublet. Its characteristic double-peak profile demonstrates that the gas is in Keplerian rotation and points to an emitting region extending out to ∼15–30 AU. The OH emission correlates with disk geometry as it …

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