Near-Infrared, Adaptive Optics Observations of the T Tauri Multiple-Star System

With high-angular-resolution, near-infrared observations of the young stellar object T Tauri at the end of 2002, we show that, contrary to previous reports, none of the three infrared components of T Tau coincide with the compact radio source that has apparently been ejected recently from the system (Loinard, Rodriguez, and Rodriguez 2003). The compact radio source and one of the three infrared objects, T Tau Sb, have distinct paths that depart from orbital or uniform motion between 1997 and 2000, perhaps indicating that their interaction led to the ejection of the radio source. The path that T Tau Sb took between 1997 and 2003 may indicate that this star is still bound to the presumably more massive southern component, T Tau Sa. The radio source is absent from our near-infrared images and must therefore be fainter than K = 10.2 (if located within 100 mas of T Tau Sb, as the radio data would imply), still consistent with an identity as a low-mass star or substellar object.Comment: 11 pages, 3 figures, submitted to ApJ

Determinations of SIII, OIV and NeV abundances in planetary nebulae from IR lines

Airborne observations of the infrared forbidden lines (SIII) 18.71 microns, (NeV) 24.28 microns and (OIV) 25.87 microns were made for twelve planetary nebulae. One or more of the lines was detected in seven of these nebulae and ionic abundances were calculated. These results are insensitive to nebula temperatures, in contrast to the case for optical or UV lines. However, density estimates from optical and UV forbidden lines were required to obtain abundances. The NeV infrared line flux from NGC 7662 was combined with the 3426A flux to obtain a NeV electron temperature of 11,200 (+2000, - 1100) K, which overlaps OIII temperature measurements. Since the ionization potential of NeIV is much greater than that of OII, T sub e (NeV) would be expected to be much greater than T sub e (OIII). In fact, numerical models predict T sub e (NeV) (16-20) x 1000 K. This discrepancy may indicate inaccuracies in currently available atomic parameters for NeV

Mid-Infrared Imaging of the Bipolar Planetary Nebula M2-9 from SOFIA

We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 $\mu m$. A bright central point source, unresolved with SOFIA's $\sim$ 4${''}$-to-5${''}$ beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 $\mu m$ and beyond. The photometry between 10 and 25 $\mu m$ is well fit by the emission predicted from a stratified disk seen at large inclination, as has been proposed for this source by Lykou et al and by Smith and Gehrz. The principal new results in this paper relate to the distribution and properties of the dust that emits the infrared radiation. In particular, a considerable fraction of this material is spread uniformly through the lobes, although the dust density does increase at the sharp outer edge seen in higher resolution optical images of M2-9. The dust grain population in the lobes shows that small ($$ 1 $\mu m$) particles appear to be present in roughly equal amounts by mass. We suggest that collisional processing within the bipolar outflow plays an important role in establishing the particle size distribution.Comment: 40 pages, 9 figures, 2 table

Moderate Resolution Spectroscopy For The Space Infrared Telescope Facility (SIRTF)

A conceptual design for an infrared spectrometer capable of both low resolution (λ/Δ-λ = 50; 2.5-200 microns) and moderate resolution (1000; 4-200 microns) and moderate resolution (1000; 4-200 microns) has been developed. This facility instrument will permit the spectroscopic study in the infrared of objects ranging from within the solar system to distant galaxies. The spectroscopic capability provided by this instrument for SIRTF will give astronomers orders of magnitude greater sensitivity for the study of faint objects than had been previously available. The low resolution mode will enable detailed studies of the continuum radiation. The moderate resolution mode of the instrument will permit studies of a wide range of problems, from the infrared spectral signatures of small outer solar system bodies such as Pluto and the satellites of the giant planets, to investigations of more luminous active galaxies and QS0s at substantially greater distances. A simple design concept has been developed for the spectrometer which supports the science investigation with practical cryogenic engineering. Operational flexibility is preserved with a minimum number of mechanisms. The five modules share a common aperture, and all gratings share a single scan mechanism. High reliability is achieved through use of flight-proven hardware concepts and redundancy. The design controls the heat load into the SIRTF cryogen, with all heat sources other than the detectors operating at 7K and isolated from the 4K cold station. Two-dimensional area detector arrays are used in the 2.5-120μm bands to simultaneously monitor adjacent regions in extended objects and to measure the background near point sources

The Extraordinary Mid-infrared Spectrum of the Blue Compact Dwarf Galaxy SBS0335-052

SBS0335-052 is a blue compact dwarf galaxy (BCD) with one of the lowest known metallicities, Z$\sim$Z_{\sun}/41, making it a local example of how primordial starburst galaxies and their precursors might appear. A spectrum obtained with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope clearly shows silicate absorption features, emission lines of [SIV] and [NeIII], and puts strong upper limits on the PAH emission features. The observed low resolution spectrum (R~90) extends from 5.3 to 35microns and peaks at ~28microns. The spectrum is compared to IRS observations of the prototypical starburst nucleus NGC7714. SBS0335-052 is quite unlike normal starburst galaxies, which show strong PAH bands, low ionization emission lines, and a continuum peak near 80microns. The continuum difference for $\lambda >30 \mu$m implies a substantial reduction in the mass of cold dust. If the spectrum of this very low metallicity galaxy is representative of star forming galaxies at higher redshifts, it may be difficult to distinguish them from AGNs which also show relatively featureless flat spectra in the mid-IR.Comment: Accepted in ApJ Sup. Spitzer Special Issue, 4 pages, 2 figure

Decomposing Dusty Galaxies. I. Multi-Component Spectral Energy Distribution Fitting

We present a new multi-component spectral energy distribution (SED) decomposition method and use it to analyze the ultraviolet to millimeter wavelength SEDs of a sample of dusty infrared-luminous galaxies. SEDs are constructed from spectroscopic and photometric data obtained with the Spitzer Space Telescope, in conjunction with photometry from the literature. Each SED is decomposed into emission from populations of stars, an AGN accretion disk, PAHs, atomic and molecular lines, and distributions of graphite and silicate grains. Decompositions of the SEDs of the template starburst galaxies NGC7714 and NGC2623 and the template AGNs PG0804+761 and Mrk463 provide baseline properties to aid in quantifying the strength of star-formation and accretion in the composite systems NGC6240 and Mrk1014. We find that obscured radiation from stars is capable of powering the total dust emission from NGC6240, although we cannot rule out a contribution from a deeply embedded AGN visible only in X-rays. The decomposition of Mrk1014 is consistent with ~65% of its power emerging from an AGN and ~35% from star-formation. We suggest that many of the variations in our template starburst SEDs may be explained in terms of the different mean optical depths through the clouds of dust surrounding the young stars within each galaxy. Prompted by the divergent far-IR properties of our template AGNs, we suggest that variations in the relative orientation of their AGN accretion disks with respect to the disks of the galaxies hosting them may result in different amounts of AGN-heated cold dust emission emerging from their host galaxies. We estimate that 30-50% of the far-IR and PAH emission from Mrk1014 may originate from such AGN-heated material in its host galaxy disk.Comment: 27 pages, 12 figures. Accepted for publication in the Ap

Spitzer-IRS Spectroscopy of the Prototypical Starburst Galaxy NGC7714

We present observations of the starburst galaxy NGC 7714 with the Infrared Spectrograph IRS on board the Spitzer Space Telescope. The spectra yield a wealth of ionic and molecular features that allow a detailed characterization of its properties. NGC 7714 has an HII region-like spectrum with strong PAH emission features. We find no evidence for an obscured active galactic nucleus, and with [NeIII]/[NeII]~0.73, NGC7714 lies near the upper end of normal-metallicity starburst galaxies. With very little slicate absorption and a temperature of the hottest dust component of 340K, NGC 7714 is the perfect template for a young, unobscured starburstComment: To appear in the special ApJSS issue on early results from Spitze

Toxicities and residual effects of toxic baits containing spinosad or malathion to control the adult Anastrepha fraterculus (Diptera: Tephritidae).

An important objective of Integrated Pest Management (IPM) is to reduce chemical contamination of the environment and food; for example by replacing broadcast sprays with selective toxic baits. The objective of the study was to evaluate the toxicity and residual effects of the a ready-for-use commercial bait Success* 0.02 CB®, which contains 0.24 g a.i. L-1 of spinosad, and to compare it’s performance to a few other formulations with spinosad and malathion mixed either in hydrolyzed corn protein (Biofruit® 3%) or in sugarcane molasses (7%) on adults Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) in the laboratory, greenhouse and field conditions. In the laboratory, formulations with spinosad caused mortality equivalent to malathion-based toxic baits 96 h after exposure of the insects, regardless of the attractive substance used. In the greenhouse, Success* 0.02 CB®, resulted in mortality of 81.9% of A. fraterculus adults 7 days after application of treatment; being significantly superior to either standard spinosad or malathion treatments (mortality between 44.1 to 62.1%) in the same evaluation period. In field, in the absence of rain, Success* 0.02 CB® and spinosad formulations with Biofruit® 3% or sugarcane molasses (7%) caused mortalities from 70.0 to 83.0% up to 7 DAT, not differing statistically from the malathion treatments (mortality of 100%) during this time. However, at 10 DAT only malathion formulations with Biofruit® 3% or sugarcane molasses (7%) substantial mortalities, i.e., 73.3% and 76.7%, respectively, which were superior to formulations with spinosad (mortality < 45%). However, at 14 DAT all tested formulations caused less than 40% mortality of A. fraterculus adults. One day after a rain (3.8 mm), the formulations with malathion caused mortalities between 56.7 and 81.8%, which were statistically superior to the formulations with spinosad (mortality < 20%). However, after the occurrence of an additional 0.4 mm of rain, all formulations caused mortality lower than 15%. Biofruit® 3% can be used as a replacement for sugarcane molasses (7%) in formulating toxic baits and Success* 0.02 CB® and other formulations with spinosad may be used to replace malathion to manage populations of A. fraterculus. In practical field operations, the effectiveness of toxic bait formulations may be extended by applying them to the lower canopy where they are partially protected from rain. Key Words: attract and kill control; South American fruit fly; insecticide; integrated pest management Um dos principais objetivos do Manejo Integrado de Praga (MIP) é a redução da contaminação do ambiente e alimentos. Desta forma, o objetivo deste estudo foi avaliar a toxicidade e o efeito residual da formulação comercial Success* 0.02 CB® e formulações com inseticida espinosade e malation misturados com soluções aquosas de proteina hidrolisada de milho (Biofruit® 3%) ou melaço de cana-de-açúcar (7%) sobre adultos de A. fraterculus em condições de laboratório, casa de vegetação e campo. Em laboratório, a toxicidade das formulações com inseticida espinosade causou mortalidade equivalente as formulações com inseticida malation 96 horas após a exposição dos insetos, independentemente da substância atrativa usada. Em casa de vegetação, a formulação Success* 0.02 CB® , resultou em mortalidade de 81,9% dos adultos de A. fraterculus 7 DAT, sendo significativamente superior a mortalidade observa com tratamentos com espinosade ou malation (mortalidade entre 44 a 62,1%) no mesmo período de avaliação. Em campo, na ausência de chuva, a formulação Success* 0.02® CB e as formulações com Biofruit® 3% e melaço de cana de açúcar (7%) misturadas com espinosade causaram mortalidade de 70,0 a 83,0%, 7 DAT, não diferindo estatisticamente do tratamento com malation (100% de mortalidade) neste tempo. No entanto, 10 DAT, as formulações Biofruit® 3% e melaço de cana-de-açúcar (7%) misturadas com malation causaram mortalidade de 73,3 e 76,7, respectivamente, sendo superior estatisticamente das formulações com espinosade (mortalidade < 45%). Contudo, 14 DAT, todas as formulações testadas proporcionaram mortalidade menor que 40% de adultos de A. fraterculus. Na presença de chuva (3,8 mm), as formulações com malation proporcionaram mortalidade superior a 55%, 3 DAT, sendo superior estatisticamente das formulações com espinosade (mortalidade < 20%). Contudo, após a ocorrência de mais 0,4 mm Harter et al.: Toxic baits to control the Anastrepha fraterculus 203 de chuva (5 DAT), todas as formulações causaram mortalidade inferior a 15%. A proteína hidrolisada de milho (Biofruit® 3%) pode ser usada em substituição ao melaço de cana-de-açúcar (7%) nas formulações de isca tóxicas e a formulação comercial Success* 0.02 CB® eas formulações com inseticidas espinosade em iscas tóxicas pode ser usadas para substituir o inseticida malation para o manejo da população de A. fraterculus. Palavras Chave: Controle atrai e mata; mosca das frutas Sul Americana; inseticidas; Manejo Integrado de Praga