A high resolution mid-infrared survey of water emission from protoplanetary disks

We present the largest survey of spectrally resolved mid-infrared water emission to date, with spectra for 11 disks obtained with the Michelle and TEXES spectrographs on Gemini North. Water emission is detected in 6 of 8 disks around classical T Tauri stars. Water emission is not detected in the transitional disks SR 24 N and SR 24 S, in spite of SR 24 S having pre-transitional disk properties like DoAr 44, which does show water emission (Salyk et al. 2015). With R~100,000, the TEXES water spectra have the highest spectral resolution possible at this time, and allow for detailed lineshape analysis. We find that the mid-IR water emission lines are similar to the "narrow component" in CO rovibrational emission (Banzatti & Pontoppidan 2015), consistent with disk radii of a few AU. The emission lines are either single peaked, or consistent with a double peak. Single-peaked emission lines cannot be produced with a Keplerian disk model, and may suggest that water participates in the disk winds proposed to explain single-peaked CO emission lines (Bast et al. 2011, Pontoppidan et al. 2011). Double-peaked emission lines can be used to determine the radius at which the line emission luminosity drops off. For HL Tau, the lower limit on this measured dropoff radius is consistent with the 13 AU dark ring (ALMA partnership et al. 2015). We also report variable line/continuum ratios from the disks around DR Tau and RW Aur, which we attribute to continuum changes and line flux changes, respectively. The reduction in RW Aur line flux corresponds with an observed dimming at visible wavelengths (Rodriguez et al. 2013).Comment: To appear in the Astrophysical Journa

MIRAO: a mid-IR adaptive optics system design for TMT

We present a design of a thermal-infrared optimized adaptive optics system for the TMT 30-meter telescope. The approach makes use of an adaptive secondary but during an initial implementation contains a more conventional ambient-temperature optical relay and deformable mirror. The conventional optical relay is used without sacrificing the thermal background by using multiple off-axis laser guide stars to avoid a warm dichroic in the common path. Three laser guide stars, equally spaced 75" off axis, and a "conventional" 30×30 deformable mirror provide a Strehl > 0.9 at wavelengths longer than 10 microns and the LGS beams can be passed to the LGS wavefront sensors with pickoff mirrors while a one-arcminute field is passed unvignetted to the science instrument and NGS WFSs. The overall design is relatively simple with a wavefront correction similar to existing high-order systems (e.g. 30×30) but still provides competitive performance over the higher-order TMT NIR AO design at wavelengths as short as 3 microns due to its reduced thermal emissivity. We present our figures of merit and design considerations within the context of the science drivers for high-spectral resolution NIR/MIR spectroscopy at 5-28 microns on a 30-meter ground-based telescope

[S IV] in the NGC 5253 Supernebula: Ionized Gas Kinematics at High Resolution

The nearby dwarf starburst galaxy NGC 5253 hosts a deeply embedded radio-infrared supernebula excited by thousands of O stars. We have observed this source in the 10.5{\mu}m line of S+3 at 3.8 kms-1 spectral and 1.4" spatial resolution, using the high resolution spectrometer TEXES on the IRTF. The line profile cannot be fit well by a single Gaussian. The best simple fit describes the gas with two Gaussians, one near the galactic velocity with FWHM 33.6 km s-1 and another of similiar strength and FWHM 94 km s-1 centered \sim20 km s-1 to the blue. This suggests a model for the supernebula in which gas flows towards us out of the molecular cloud, as in a "blister" or "champagne flow" or in the HII regions modelled by Zhu (2006).Comment: Accepted for publication in the Astrophysical Journal 4 June 201

Modelling the Interactions of Soils, Climate, and Management for Grass Production in England and Wales

This study examines the effectiveness of a model called LINGRA-N-Plus to simulate the interaction of climate, soil and management on the green leaf and total dry matter yields of ryegrass in England and Wales. The LINGRA-N-Plus model includes modifications of the LINGRA-N model such as temperature- and moisture-dependent soil nitrogen mineralization and differential partitioning to leaves and stems with thermal time from the last harvest. The resulting model was calibrated against the green leaf and total grass yields from a harvest interval x nitrogen application experiment described by Wilman et al. (1976). When the LINGRA-N-Plus model was validated against total grass yields from nitrogen experiments at ten sites described by Morrison et al. (1980), its modelling efficiency improved greatly compared to the original LINGRA-N. High predicted yields, at zero nitrogen application, were related to soils with a high initial nitrogen content. The lowest predicted yields occurred at sites with low rainfall and shallow rooting depth; mitigating the effect of drought at such sites increased yields by up to 4 t ha−1. The results highlight the usefulness of grass models, such as LINGRA-N-Plus, to explore the combined effects of climate, soil, and management, like nitrogen application, and harvest intervals on grass productivity

The Grizzly, February 17, 1989

Malicious Arson Attempt Suspected In Fire • Board of Dirs. Calls for Big, but Beneficial Bucks • Letter: Let\u27s Keep Campbell! • WVOU Far From FM Waves • Glastnost Russian Roulette? • Freeman Displays Her Patchwork • Grim: No Meal Like a Home Meal • Drug Awareness a Downer • Title in Sight • Wrestlers Cruising at Unprecedented 21-2 • \u27Nasts O.K. • Intro. to Judaism Offered • Women\u27s Indoor Crushes \u27Em • Men\u27s Track \u27Sloshing\u27 Along • Aquabears Paddlin\u27 Wellhttps://digitalcommons.ursinus.edu/grizzlynews/1229/thumbnail.jp

The Grizzly, October 5, 1993

Girls\u27 Pledging Returns Full-Force! • India Shattered by Earthquakes • Acting PA Governor Will Hold TV Town Meeting at Ursinus • Freshman to Compete in Karate\u27s World Cup • Henry Moore Exhibit Opens Today • Charles Fambrough Quintet to Play Ursinus • Editorial: Pledging; Wellness Center • Intramurals Begin: Sign Up! • Bears Crush Garnet Into Pebbleshttps://digitalcommons.ursinus.edu/grizzlynews/1320/thumbnail.jp

The Grizzly, October 2, 1987

Academic Standards Set • Potential Pledges Prepare for New State Policy • Student Accosted on Main St. • Letters: Call to Remember Yom Kippur; Paint This!; Response to Student Apathy • What\u27s a Bork? Find out! • Graduate Study Abroad Offered • Ursinus is Everywhere • Super Sunday\u27s Last Chance • Dance Forum Gets Down • Bears Won! • Bears Set Spikes • Soccer\u27s Record: 4-3 • Hockey Handed First Setback • Bear Pack Continues Winning • Waged War Won by Phils • O\u27Donohue Claims Honors • Concert Benefit Scheduled • Dated Parties Hosed • No Lapse in New Floydhttps://digitalcommons.ursinus.edu/grizzlynews/1194/thumbnail.jp