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We describe a novel use for superconducting flux pumping, namely a method for magnetizing a planar magnetic field source. The method is useful for many applications, but we illustrate it with the planar Penning trap with applications in quantum technology. A flux pumping mechanism and associated mathematical model are described. The method allows for complete control of the induced persistent current in a double-loop superconducting structure, whereby the final current is a known function of the applied flux and the loop geometry. We have tested our flux pumping technique and found excellent agreement with the theory.

The youngest, closest and most compact embedded massive star cluster known excites the supernebula in the nearby dwarf galaxy NGC 5253. It is a crucial target and test case for studying the birth and evolution of the most massive star clusters. We present observations of the ionized gas in this source with high spatial and spectral resolution. The data includes continuum images of free-free emission with ~0.15'' resolution made with the JVLA at 15, 22 and 33 GHz, and a full data cube of the [SIV]10.5 micron fine-structure emission line with ~4.5 km/s velocity resolution and 0.3'' beam, obtained with TEXES on Gemini North. We find that 1) the ionized gas extends out from the cluster in arms or jets, and 2) the ionized gas comprises two components offset both spatially and in velocity. We discuss mechanisms that may have created the observed velocity field; possibilities include large-scale jets or a subcluster falling onto the main source., Comment: Accepted for publication in MNRAS, 16 June 2020

High mass proto-stars create Ultra-Compact Hii regions (UCHII) at the stage of evolution when most of the accretion is finished but the star is still heavily embedded in molecular material. The morphologies of UCHII regions reflect the interactions of stellar winds, stellar motions, and density structure in the molecular cloud; they are complex and it has been very difficult to interpret them. We here present data obtained with TEXES on the NASA IRTF of the [NeII] emission line in the proto-cluster of young OB stars in W33 Main. The data cube has a spatial resolution of ~ 1.4 arcsec and true velocity resolution ~ 5 km/s; with A ~ 0.02Av it is relatively unaffected by extinction. We have run 3D hydrodynamic and line profile simulations, using PLUTO and RADMC-3D, of the gas structures created by multiple windy stars moving relative to each other through the ambient cloud. By iterative comparison of the data cube and the simulations, we arrive at models that reproduce the different morphology and kinematic structure of each UCHII region in W33 Main. The results indicate that each sub-source probably holds multiple exciting stars, permitting an improved view of the stellar population, and finds the stellar trajectories, which may determine the dynamical development of the proto-cluster., 20 pages, 12 figures, Accepted by MNRAS 18 October 2021

24 pags., 11 figs., 2 tabs., High spectral resolution observations toward the low mass-loss rate C-rich, J-type asymptotic giant branch (AGB) star Y CVn were carried out at 7.5, 13.1, and 14.0 μm with the Echelon-cross-echelle Spectrograph mounted on the Stratospheric Observatory for Infrared Astronomy and the Texas Echelon-cross-echelle Spectrograph on the Infrared Telescope Facility. Around 130 HCN and H13CN lines of bands ν2, 2ν2, 2ν2 - ν2, 3ν2 - 2ν2, 3ν2 - ν2, and 4ν2 - 2ν2 were identified involving lower levels with energies up to ? 3900 K. These lines were complemented with the pure rotational lines J = 1-0 and 3-2 of the vibrational states up to 2ν2 acquired with the Institut de Radioastronomie Millimétrique 30 m telescope, and with the continuum taken with Infrared Space Observatory. We analyzed the data in detail by means of a ro-vibrational diagram and with a code written to model the absorption and emission of the circumstellar envelope of an AGB star. The continuum is mostly produced by the star with a small contribution from dust grains comprising warm to hot SiC and cold amorphous carbon. The HCN abundance distribution seems to be anisotropic close to Y CVn and in the outer layers of its envelope. The ejected gas is accelerated up to the terminal velocity (? 8 km s-1) from the photosphere to ? 3R? , but there is evidence of higher velocities (? 9-10 km s-1) beyond this region. In the vicinity of the star, the line widths are as high as ? 10 km s-1, which implies a maximum turbulent velocity of 6 km s-1 or the existence of other physical mechanisms probably related to matter ejection that involve higher gas expansion velocities than expected. HCN is rotationally and vibrationally out of local thermodynamic equilibrium throughout the whole envelope. It is surprising that a difference of about 1500 K in the rotational temperature at the photosphere is needed to explain the observations at 7.5 and 13-14 μm. Our analysis finds a total HCN column density that ranges from ? 2.1 × 1018 to 3.5 × 1018 cm-2, an abundance with respect to H2 of 3.5 × 10-5 to 1.3 × 10-4, and a 12C/13C isotopic ratio of ? 2.5 throughout the whole envelope., The research leading to these results has received funding support from the European Research Council under the European Union’s Seventh Framework Program (FP/2007-2013) / ERC Grant Agreement n. 610256 NANOCOSMOS. EJM acknowledges financial support for this work through award #06_0144 which was issued by USRA and provided by NASA. MJR and EXES observations are supported by NASA cooperative agreement 80NSSC19K1701. MSG thanks Spanish MCIN through grant AYA2016-78994-P. Based in part on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NNA17BF53C, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. This work is based on observations carried out under project numbers 155-16 and 048-17 with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This publication makes use of data products from the Widefield Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration

We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical conditions toward stars behind the Taurus Molecular Cloud (TMC). New high-resolution spectra at visible and near infrared wavelengths of interstellar Ca II, Ca I, K I, CH, CH^+, C2, CN, and CO toward HD28975 and HD29647 are combined with data at visible wavelengths and published CO results from ultraviolet measurements for HD27778 and HD30122. Gas densities and temperatures are inferred from C2, CN, and CO excitation and CN chemistry. Our results for HD29647 are noteworthy because the CO column density is 10^{18} cm^{-2} while C2 and CO excitation reveals a temperature of 10 K and density about 1000 cm^{-3}, more like conditions found in dark molecular clouds. Similar results arise from our chemical analysis for CN through reactions involving observations of CH, C2, and NH. Enhanced potassium depletion and a reduced CH/H2 column density ratio also suggest the presence of a dark cloud. The directions toward HD27778 and HD30122 probe molecule-rich diffuse clouds, which can be considered CO-dark gas, while the sight line toward HD28975 represents an intermediate case. Maps of dust temperature help refine the description of the material along the four sight lines and provide an estimate of the distance between HD29647 and a clump in the TMC. An Appendix provides results for the direction toward HD26571; this star also probes diffuse molecular gas., 11 figures, 14 tables, 75 pages; higher quality maps appear in the published version

We theoretically investigate the coupling of a single electron in a planar Penning trap with a remote superconducting microwave (MW) cavity. Coupling frequencies around [Formula: see text] MHz can be reached with resonators with a loaded quality factor of [Formula: see text], allowing for the strong coupling regime. The electron and the cavity form a system of two coupled quantum harmonic oscillators. This is a hybrid and linear microwave quantum network. We show that the coherent interaction can be sustained over distances of a few mm up to several cm. Similar to classical linear MW circuits, the coherent quantum exchange of photons is ruled by the impedances of the electron and the cavity. As one concrete application, we discuss the entanglement of the cyclotron motions of two electrons located in two separate traps.

Over the last eight years, a rich dataset of mid-infrared CH4 observations from the TEXES instrument at IRTF has been used to characterize the thermal evolution of Jupiter's stratosphere. These data were used to produce vertically-resolved temperature maps between latitudes of 50{\deg}S and 50{\deg}N, allowing us to track approximately two periods of Jupiter's quasi-quadrennial oscillation (QQO). During the first five years of observations, the QQO has a smooth sinusoidal pattern with a period of 4.0$\pm$0.2 years and an amplitude of 7$\pm$1 K at 13.5 mbar (our region of maximum sensitivity). In 2017, we note an abrupt change to this pattern, with the phase being shifted backwards by ~1 year. Searching for possible causes of this QQO delay, we investigated the TEXES zonally-resolved temperature retrievals and found that in May/June 2017, there was an unusually warm thermal anomaly located at a latitude of 28{\deg}N and a pressure of 1.2 mbar, moving westward with a velocity of 19$\pm$4 m/s. We suggest that there may be a link between these two events., Comment: 14 pages, 7 figures

We present new [Ne II] (12.8 micron) IRTF/TEXES observations of the Galactic Center HII regions H1 and H2, which are at a projected distance of ~11 pc from the center of the Galaxy. The new observations allow to map the radial velocity distributions of ionized gas. The high spectroscopic resolution (~4 km/s) helps us to disentangle different velocity components and enables us to resolve previous ambiguity regarding the nature of these sources. The spatial distributions of the intensity and radial velocity of the [Ne II] line are mapped. In H1, the intensity distributions of the Paschen-\alpha (1.87 micron) and [Ne II] lines are significantly different, which suggests a strong variation of extinction across the HII region of A_K~0.56. The radial velocity distributions across these HII regions are consistent with the predictions of a bow-shock model for H1 and the pressure-driven model for H2. Furthermore, we find a concentration of bright stars in H2. These stars have similar H-K_s colors and can be explained as part of a 2 Myr old stellar cluster. H2 also falls on the orbit of the molecular clouds, suggested to be around Sgr A*. Our new results confirm what we had previously suggested: the O supergiant P114 in H1 is a runaway star, moving towards us through the -30-0 {km/s} molecular cloud, whereas the O If star P35 in H2 formed in-situ, and may mark the position of a so-far unknown small star cluster formed within the central 30 pc of the Galaxy., Comment: The paper has been accepted to be published in MNRAS, 30 pages, 14 figures

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)., To appear in the Astrophysical Journal

Observations of the ejecta from the final flash (FF) of helium shell burning in Sakurai’s Object (V4334 Sgr) are presented for 2015–2019, a period ∼20–24 yr after discovery. Adaptive optics images at K s trace the expanding debris. While most of the ejecta mass is in ∼200 K dust, a small fraction, ∼0.4%, of the dust mass is at ∼760 K. The 760 K continuum dominates the near-IR images. Spatial-spectral images in He i 10830 Å show an ∼16 diameter bipolar planetary nebula at position angle 21° ± 5° with the SW moving toward us and the NE moving away. Seen in integrated light, the nebula is nearly circular. Near-IR continuum images show ejecta moving radially away from a bright central point source. High-resolution mid-IR spectra reveal molecular hydrocarbon lines with an expansion velocity of 270 ± 5 km s−1 seen in absorption against the dust continuum. The hydrocarbons originate in material produced in the FF. The bipolar nebula and debris clouds are discussed in the context of a highly inclined disk model. The proper motion has been measured placing V4334 Sgr in the thick disk population. There is no evidence that a hot white dwarf Wolf–Rayet ([WR]) wind has emerged; no [WR] spectral features were detected. The possibility of a binary companion involved in the evolution is discussed.

We present a planar, scalable magnetic field source, originally conceived for a chip ion trap. It consists of two symmetric sections, each with several independent currents arranged in coplanar, concentric rectangular loops. The currents allow for tuning the strength of the field and its lowest-order derivatives at one discretional position along the source's vertical symmetry axis, a few mm above its surface. We describe the construction and calibration of the device and the cryogenic setup. The two most important current configurations for a Penning ion trap, the homogeneous field and the magnetic bottle, are investigated experimentally. Homogeneous fields around 0.5 T are routinely reached. We discuss the maximum attainable field, and we briefly describe ongoing further developments aiming at homogeneous fields well above 1 T.

We have performed a high resolution 4-13 ${\mu}m$ spectral survey of the hot molecular gas associated with the massive protostars AFGL 2591 and AFGL 2136, utilising the Echelon-Cross-Echelle-Spectrograph (EXES) on-board the Stratospheric Observatory for Infrared Astronomy (SOFIA), and the iSHELL instrument and Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility (IRTF). Here we present results of this survey with analysis of CO, HCN, C$_2$H$_2$, NH$_3$ and CS, deriving the physical conditions for each species. Also from the IRTF, iSHELL data at 3 ${\mu}m$ for AFGL 2591 are presented that show HCN and C$_2$H$_2$ in emission. In the EXES and TEXES data, all species are detected in absorption, and temperatures and abundances are found to be high (600 K and 10$^{-6}$, respectively). Differences of up to an order of magnitude in the abundances of transitions that trace the same ground state level are measured for HCN and C$_2$H$_2$. The mid-infrared continuum is known to originate in a disk, hence we attribute the infrared absorption to arise in the photosphere of the disk. As absorption lines require an outwardly decreasing temperature gradient, we conclude that the disk is heated in the mid-plane by viscous heating due to accretion. We attribute the near-IR emission lines to scattering by molecules in the upper layers of the disk photosphere. The absorption lines trace the disk properties at 50 AU where a high temperature gas-phase chemistry is taking place. Abundances are consistent with chemical models of the inner disk of Herbig disks.

We present the detection of C4H2 for first time in the envelope of the C-rich AGB star IRC+10216 based on high spectral resolution mid-IR observations carried out with the Texas Echelon-cross-Echelle Spectrograph (TEXES) mounted on the Infrared Telescope Facility (IRTF). The obtained spectrum contains 24 narrow absorption features above the detection limit identified as lines of the ro-vibrational C4H2 band nu6+nu8(sigma_u^+). The analysis of these lines through a ro-vibrational diagram indicates that the column density of C4H2 is 2.4(1.5)E+16 cm^(-2). Diacetylene is distributed in two excitation populations accounting for 20 and 80% of the total column density and with rotational temperatures of 47(7) and 420(120) K, respectively. This two-folded rotational temperature suggests that the absorbing gas is located beyond ~0.4"~20R* from the star with a noticeable cold contribution outwards from ~10"~500R*. This outer shell matches up with the place where cyanoacetylenes and carbon chains are known to form due to the action of the Galactic dissociating radiation field on the neutral gas coming from the inner layers of the envelope., 7 pages, 5 figures. Accepted for publication in the ApJ

Acetylene (C$_2$H$_2$) and ethane (C$_2$H$_6$) are both produced in the stratosphere of Jupiter via photolysis of methane (CH$_4$). Despite this common source, the latitudinal distribution of the two species is radically different, with acetylene decreasing in abundance towards the pole, and ethane increasing towards the pole. We present six years of NASA IRTF TEXES mid-infrared observations of the zonally-averaged emission of methane, acetylene and ethane. We confirm that the latitudinal distributions of ethane and acetylene are decoupled, and that this is a persistent feature over multiple years. The acetylene distribution falls off towards the pole, peaking at $\sim$30$^{\circ}$N with a volume mixing ratio (VMR) of $\sim$0.8 parts per million (ppm) at 1 mbar and still falling off at $\pm70^\circ$ with a VMR of $\sim$0.3 ppm. The acetylene distributions are asymmetric on average, but as we move from 2013 to 2017, the zonally-averaged abundance becomes more symmetric about the equator. We suggest that both the short term changes in acetylene and its latitudinal asymmetry is driven by changes to the vertical stratospheric mixing, potentially related to propagating wave phenomena. Unlike acetylene, ethane has a symmetric distribution about the equator that increases toward the pole, with a peak mole fraction of $\sim$18 ppm at about $\pm50^{\circ}$ latitude, with a minimum at the equator of $\sim$10 ppm at 1 mbar. [...] The equator-to-pole distributions of acetylene and ethane are consistent with acetylene having a shorter lifetime than ethane that is not sensitive to longer advective timescales, but is augmented by short-term dynamics, such as vertical mixing. Conversely, the long lifetime of ethane allows it to be transported to higher latitudes faster than it can be chemically depleted., 39 pages, 9 Figures, 2 tables, in press

We present high spectral resolution mid-IR observations of SiS towards the C-rich AGB star IRC+10216 carried out with the Texas Echelon-cross-Echelle Spectrograph mounted on the NASA Infrared Telescope Facility. We have identified 204 ro-vibrational lines of 28Si32S, 26 of 29Si32S, 20 of 28Si34S, and 15 of 30Si32S in the frequency range 720–790 cm−1. These lines belong to bands v = 1–0, 2–1, 3–2, 4–3, and 5–4, and involve rotational levels with Jlow ≲ 90. About 30 per cent of these lines are unblended or weakly blended and can be partially or entirely fitted with a code developed to model the mid-IR emission of a spherically symmetric circumstellar envelope composed of expanding gas and dust. The observed lines trace the envelope at distances to the star ≲35R⋆ (≃0.7 arcsec). The fits are compatible with an expansion velocity of 1 + 2.5(r/R⋆ − 1) km s−1 between 1 and 5R⋆, 11 km s−1 between 5 and 20R⋆, and 14.5 km s−1 outwards. The derived abundance profile of 28Si32S with respect to H2 is 4.9 × 10−6 between the stellar photosphere and 5R⋆, decreasing linearly down to 1.6 × 10−6 at 20R⋆ and to 1.3 × 10−6 at 50R⋆. 28Si32S seems to be rotationally under local thermodynamic equilibrium (LTE) in the region of the envelope probed with our observations and vibrationally out of LTE in most of it. There is a red-shifted emission excess in the 28Si32S lines of band v = 1−0 that cannot be found in the lines of bands v = 2−1, 3–2, 4–3, and 5–4. This excess could be explained by an enhancement of the vibrational temperature around 20R⋆ behind the star. The derived isotopic ratios 28Si/29Si, and 32S/34S are 17 and 14, compatible with previous estimates., JPF was supported during part of this study by the UNAM through a postdoctoral fellowship. We thank the Spanish MINECO/MICINN for funding support through grants AYA2009-07304, AYA2012-32032, the ASTROMOL Consolider project CSD2009-00038 and the European Research Council (ERC Grant 610256: NANOCOSMOS). MJR is supported by grant AST 03-07497. Development of TEXES was supported by grants from the NSF and USRA. MJR, JHL, and others want to thank IRTF, which is operated by the University of Hawaii under Cooperative Agreement NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program.

The abundance of H2 in molecular clouds, relative to the commonly used tracer CO, has only been measured toward a few embedded stars, which may be surrounded by atypical gas. We present observations of near-infrared absorption by H2, CO, and dust toward stars behind molecular clouds, providing a representative sample of these molecules in cold molecular gas, primarily in the Taurus Molecular Cloud. We find N_H2/A_V ~ 1.0x10^21 cm^-2, N_CO/A_V ~ 1.5x10^17 cm^-2 (1.8x10^17 including solid CO), and N_H2/N_CO ~ 6000. The measured N_H2/N_CO ratio is consistent with that toward embedded stars in various molecular clouds, but both are less than that derived from mm-wave observations of CO and star counts. The difference apparently results from the higher directly measured N_CO/A_V ratio., 14 pages, 7 figures

We consider models for the observed ro-vibrational absorption lines of acetylene toward NGC 7538 IRS9. The data are fit with multiple screens, each having separate column densities, rotational and vibrational excitation temperatures, and filling factors. The best fit was determined using a chi-squared minimization scheme. We find that only one screen is necessary—multiple screens gave rise to either making one of the screens transparent, or very occasionally making the two screens the same. As a result, we can place constraints on Trot, Tvib, NC2H2, and the filling factor, f. In particular we find 0.03 vib vib C2H2 = 2.4 +/- 0.6 × 1016 cm-2, or that N × f ~ 2 × 1015 cm-2. Lastly, we find 80 rot rot ~ 100 K. Physically, this can be interpreted as: (1) no vibrational excitation, (2) the warm region only fills a small fraction of the beam, (3) the C2H2 arises very near a region of 100 K. Chemically, this is in consistent with a model where the C2H2 is formed in the gas phase. It is however consistent with a scenario where the C2H2 is evaporated at 100 K from the grain surface, suggesting either a grain-surface origin or earlier origin followed by condensation. Finally, the C2H2 column density is consistent with a disk geometry.

We present a data cube of the [NeII] (12.8 μm) emission from the inner 2 pc of Sgr A West with 1″ and 4 km s−1 resolution, and with substantially better SNR and velocity resolution than previous observations of the ionized gas. We compare the observations to two proposed models of the gas motions and distribution: flows along tidally stretched streamers, and more nearly circular motions with density wave compression. The density wave model provides a considerably better fit to the kinematics of the northern arm and western arc. Neither model fits the eastern arm and bar kinematics well.To help understand the origin of the spiral pattern we calculated orbits in the potential of a black hole in a star cluster and find that the orbits naturally evolve to set up a one-armed spiral wave very similar to that observed, both spatially and kinematically. Magnetic or other perturbing forces may influence the formation of the spiral wave, but self gravity is not required. Because a density wave evolves on the orbit precession timescale, rather than the orbital timescale, a wave pattern should persist for several 105 yr. No net inward motion of the gas is required by the model. If there is inflow, it is much smaller than is suggested by the infalling streamer model.

We investigate theoretically the use of an electron in a Penning trap as a detector of single microwave photons. At the University of Sussex we are developing a chip Penning trap technology, designed to be integrated within quantum circuits. Microwave photons are guided into the trap and interact with the electron’s quantum cyclotron motion. This is an electric dipole transition, where the near field of the microwave radiation induces quantum jumps of the cyclotron harmonic oscillator. The quantum jumps can be monitored using the continuous Stern-Gerlach effect, providing the quantum non demolition signal of the microwave quanta. We calculate the quantum efficiency of photon detection and discuss the main features and technical challenges for the trapped electron as a quantum microwave sensor.

International audience; Using TEXES, the Texas Echelon cross Echelle Spectrograph, mounted on the Gemini North 8-m telescope we have mapped the spatial variation of H 2, CH 4, C 2H 2 and C 2H 6 thermal-infrared emission of Neptune. These high-spectral-resolution, spatially resolved, thermal-infrared observations of Neptune offer a unique glimpse into the state of Neptune's stratosphere in October 2007, LS = 275.4° just past Neptune's southern summer solstice ( LS = 270°). We use observations of the S(1) pure rotational line of molecular hydrogen and a portion of the nu4 band of methane to retrieve detailed information on Neptune's stratospheric vertical and meridional thermal structure. We find global-average temperatures of 163.8 ± 0.8, 155.0 ± 0.9, and 123.8 ± 0.8 K at the 7.0 × 10 -3-, 0.12-, and 2.1-mbar levels with no meridional variations within the errors. We then use the inferred temperatures to model the emission of C 2H 2 and C 2H 6 in order to derive stratospheric volume mixing ratios (hence forth, VMR) as a function of pressure and latitude. There is a subtle meridional variation of the C 2H 2 VMR at the 0.5-mbar level with the peak abundance found at -28° latitude, falling off to the north and south. However, the observations are consistent within error to a meridionally constant C 2H 2 VMR of 3.3-0.9+1.2×10-8 at 0.5 mbar. We find that the VMR of C 2H 6 at 1-mbar peaks at the equator and falls by a factor of 1.6 at -70° latitude. However, a meridionally constant VMR of 9.3-2.6+3.5×10-7 at the 1-mbar level for C 2H 6 is also statistically consistent with the retrievals. Temperature predictions from a radiative-seasonal climate model of Neptune that assumes the hydrocarbon abundances inferred in this paper are lower than the measured temperatures by 40 K at 7 × 10 -3 mbar, 30 K at 0.12 mbar and 25 K at 2.1 mbar. The radiative-seasonal model also predicts meridional temperature variations on the order of 10 K from equator to pole, which are not observed. Assuming higher stratospheric CH 4 abundance at the equator relative to the south pole would bring the meridional trends of the inferred temperatures and radiative-seasonal model into closer agreement. We have also retrieved observations of C 2H 4 emission from Neptune's stratosphere using TEXES on the NASA Infrared Telescope Facility (IRTF) in June 2003, LS = 266°. Using the observations from the middle of the planet and an average of the middle three latitude temperature profiles from the 2007 observations (9.5° of LS later, the seasonal equivalent of 9.5 Earth days within Earth's seasonal cycle), we infer a C 2H 4 VMR of 5.9-0.8+1.0×10-7 at 1.5 × 10 -3 mbar, a value that is 3.25 times that predicted by global-average photochemical models.

The composite galaxy NGC 4102 hosts a LINER nucleus and a starburst. We mapped NGC 4102 in the 12.8 micron line of [NeII], using the echelon spectrometer TEXES on the NASA IRTF, to obtain a data cube with 1.5" spatial and 25 km/s spectral, resolution. Combining near-infrared, radio, and the [NeII] data shows that the extinction to the starburst is substantial, more than 2 magnitudes at K band, and that the neon abundance is less than half solar. We find that the star formation in the nuclear region is confined to a rotating ring or disk of 4.3" (~300 pc) diameter, inside the Inner Lindblad Resonance. This region is an intense concentration of mass, with a dynamical mass of ~3 x 10^9 solar masses, and of star formation. The young stars in the ring produce the [NeII] flux reported by Spitzer for the entire galaxy. The mysterious blue component of line emission detected in the near-infrared is also seen in [NeII]; it is not a normal AGN outflow., Comment: submitted to ApJ

We present high resolution spectroscopy of mid-infrared molecular emission from two very active T Tauri stars, AS 205 N and DR Tau. In addition to measuring high signal-to-noise line profiles of water, we report the first spectrally resolved mid-infrared line profiles of HCN emission from protoplanetary disks. The similar line profiles and temperatures of the HCN and water emission indicate that they arise in the same volume of the disk atmosphere, within 1-2AU of the star. The results support the earlier suggestion that the observed trend of increasing HCN/water emission with disk mass is a chemical fingerprint of planetesimal formation and core accretion in action. In addition to directly constraining the emitting radii of the molecules, the high resolution spectra also help to break degeneracies between temperature and column density in deriving molecular abundances from low resolution mid-infrared spectra. As a result, they can improve our understanding of the extent to which inner disks are chemically active. Contrary to predictions from HCN excitation studies carried out for AS 205 N, the mid-infrared and near-infrared line profiles of HCN are remarkably similar. The discrepancy may indicate that HCN is not abundant beyond a couple of AU or that infrared pumping of HCN does not dominate at these distances., Comment: 24 pages, 19 figures, accepted for publication in the Astrophysical Journal

The circumstellar ammonia (NH$_3$) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH$_3$ abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry. In this article, we characterise the spatial distribution and excitation of NH$_3$ in the O-rich circumstellar envelopes (CSEs) of four diverse targets: IK Tau, VY CMa, OH 231.8+4.2, and IRC +10420 with multi-wavelength observations. We observed the 1.3-cm inversion line emission with the Very Large Array (VLA) and submillimetre rotational line emission with the Heterodyne Instrument for the Far-Infrared (HIFI) aboard Herschel from all four targets. For IK Tau and VY CMa, we observed the rovibrational absorption lines in the $\nu_2$ band near 10.5 $\mu$m with the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). We also attempted to search for the rotational transition within the $v_2=1$ state near 2 mm with the IRAM 30m Telescope towards IK Tau. Non-LTE radiative transfer modelling, including radiative pumping to the vibrational state, was carried out to derive the radial distribution of NH$_3$ in these CSEs. Our modelling shows that the NH$_3$ abundance relative to molecular hydrogen is generally of the order of $10^{-7}$, which is a few times lower than previous estimates that were made without considering radiative pumping and is at least 10 times higher than that in the C-rich CSE of IRC +10216. Incidentally, we also derived a new period of IK Tau from its $V$-band light curve. NH$_3$ is again detected in very high abundance in O-rich CSEs. Its emission mainly arises from localised spatial-kinematic structures that are probably denser than the ambient gas. Circumstellar shocks in the accelerated wind may contribute to the production of NH$_3$. (Abridged abstract), Comment: 38 pages, 28 figures, 6 tables, accepted for publication in Astronomy and Astrophysics, cross-listed to astro-ph.GA as per request by arXiv

Using TEXES at the IRTF telescope, we obtained high-resolution, mid-infrared, longslit spectra of Jupiter’s northern auroral “hot spot” near System III longitude 180° to search for selected pure-rotational and ν 1 → ν 2 difference band lines of H 3 + . Because these lines have not been investigated in the laboratory, we used theoretically predicted frequencies and line intensities to guide this search. No pure rotational H 3 + line emission was detected near the predicted frequencies. However, two metastable ν 1 → ν 2 difference band lines appear to have been marginally detected at the 68% confidence level (1 − σ ). The non-detection of the pure rotational line sets a 1 − σ upper limit to the vertical column abundance of H 3 + in the northern jovian aurora of 8.4 × 10 12 cm −2 , which is independent of any assumption concerning the departure of the vibrational H 3 + energy level populations from thermal equilibrium. This is consistent with the column 6 × 10 12 cm −2 inferred by Melin et al. [Melin, H., Miller, S., Stallard, T., Grodent, D., 2005. Icarus 178, 97–103] from their non-LTE H 3 + emission model, in which the fundamental band ro-vib levels are underpopulated by a factor of 6–10 relative to LTE. We find that the IR-inactive ν 1 levels of H 3 + , from which the jovian ν 1 → ν 2 difference band emission originates, are populated in thermal equilibrium. The difference band lines thus serve as proxies for the rotational lines in establishing the total auroral H 3 + column. As a result, the marginally detected 943.953 cm −1 ν 1 → ν 2 difference band line implies a vertical H 3 + column abundance in the range (4.5 ± 3.1) × 10 12 cm −2 , consistent with the upper limit from the rotational line. The difference band line constrains the vibrational relaxation of the IR-active ν 2 fundamental band in Jupiter’s aurora to a factor of 4.5–7.5, with an uncertainty ±68%, which supports the model-dependent result of Melin et al.

We present high resolution (R = 75,000-100,000) mid-infrared spectra of the high-mass embedded young star IRS 1 in the NGC 7538 star-forming region. Absorption lines from many rotational states of C2H2, 13C12CH2, CH3, CH4, NH3, HCN, HNCO, and CS are seen. The gas temperature, column density, covering factor, line width, and Doppler shift for each molecule are derived. All molecules were fit with two velocity components between -54 and -63 km/s. We find high column densities (~ 10e16 cm^2) for all the observed molecules compared to values previously reported and present new results for CH3 and HNCO. Several physical and chemical models are considered. The favored model involves a nearly edge-on disk around a massive star. Radiation from dust in the inner disk passes through the disk atmosphere, where large molecular column densities can produce the observed absorption line spectrum., Comment: Accepted to ApJ, 15 pages, 8 figures

We present arcsecond-scale mid-ir photometry (in the 10.5 micron N band and at 24.8 microns), and low resolution spectra in the N band (R~100) of a candidate high mass protostellar object (HMPO) in IRAS 18151-1208 and of two HMPO candidates in IRAS 20343+4129, IRS 1 and IRS 3. In addition we present high resolution mid-ir spectra (R~80000) of the two HMPO candidates in IRAS 20343+4129. These data are fitted with simple models to estimate the masses of gas and dust associated with the mid-ir emitting clumps, the column densities of overlying absorbing dust and gas, the luminosities of the HMPO candidates, and the likely spectral type of the HMPO candidate for which [Ne II] 12.8 micron emission was detected (IRAS 20343+4129 IRS 3). We suggest that IRAS 18151-1208 is a pre-ultracompact HII region HMPO, IRAS 20343+4129 IRS 1 is an embedded young stellar object with the luminosity of a B3 star, and IRAS 20343+4129 IRS 3 is a B2 ZAMS star that has formed an ultracompact HII region and disrupted its natal envelope., 40 pages, 8 figures, 3 tables. Accepted for publication in Astrophysical Journal (Part 1)

25 pags., 16 figs., 9 tabs., 2 apps., A spectral survey of IRC +10216 has been carried out in the range 11-14 μm with a spectral resolution of about 4 km s_1. We have identified a forest of lines in six bands of C2H2 involving the vibrational states from the ground to 3v5 and in two bands of HCN, involving the vibrational states from the ground up to 2v 2. Some of these transitions are observed also in H13CCH and H13CN. We have estimated the kinetic, vibrational, and rotational temperatures and the abundances and column densities of C2H 2 and HCN between 1R* and 300R* (≃1.5 × 1016 cm) by fitting about 300 of these rovibrational lines. The envelope can be divided into three regions with approximate boundaries at 0.019″ (the stellar photosphere), 0.1″ (the inner dust formation zone), and 0.4″ (outer dust formation zone). Most of the lines might require a large microturbulence broadening. The derived abundances of C 2H2 and HCN increase by factors of 10 and 4, respectively, from the innermost envelope outward. The derived column densities for both C2H2 and HCN are ≃1.6 × 1019 cm-2. Vibrational states up to 3000 K above ground are populated, suggesting pumping by near-infrared radiation from the star and innermost envelope. Low rotational levels can be considered under LTE, while those with J > 20-30 are not thermalized. A few lines require special analysis to deal with effects like overlap with lines of other molecules. © 2008. The American Astronomical Society. All rights reserved., J. C. and J. P. F. would like to thank the Spanish Ministerio de Educacion y Ciencia for funding support through grant ESP2004-665, AYA2003-2785, and the ‘‘Comunidad de Madrid’’ government under PRICIT project S-0505/ESP-0237 (ASTROCAM). During this study, J. P. F. was supported by the CSIC and the ‘‘Fondo Social Europeo’’ under internship grant from the I3P Programme. This study is supported in part by the EuropeanCommunity’s human potential Programme under contract MCRTNCT- 2004-51230, ‘‘Molecular Universe’’. M. J. R. is supported by grant AST 03-07497. Development of TEXES was supported by grants from the NSF and USRA. Observations with TEXES were supported by NSF grant AST 02-05518 and AST 06-07312. M. J. R., J. H. L., and others want to thank IRTF, which is operated by the University of Hawaii under Cooperative Agreement NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program

We report a detection of water vapor in the protoplanetary disk around DoAr 44 with the Texas Echelon Cross Echelle Spectrograph --- a visitor instrument on the Gemini north telescope. The DoAr 44 disk consists of an optically thick inner ring and outer disk, separated by a dust-cleared 36 AU gap, and has therefore been termed "pre-transitional". To date, this is the only disk with a large inner gap known to harbor detectable quantities of warm (T=450 K) water vapor. In this work, we detect and spectrally resolve three mid-infrared pure rotational emission lines of water vapor from this source, and use the shapes of the emission lines to constrain the location of the water vapor. We find that the emission originates near 0.3 AU --- the inner disk region. This characteristic region coincides with that inferred for both optically thick and thin thermal infrared dust emission, as well as rovibrational CO emission. The presence of water in the dust-depleted region implies substantial columns of hydrogen (>10^{22} cm-2) as the water vapor would otherwise be destroyed by photodissociation. Combined with the dust modeling, this column implies a gas/small-dust ratio in the optically thin dusty region of >1000. These results demonstrate that DoAr 44 has maintained similar physical and chemical conditions to classical protoplanetary disks in its terrestrial-planet forming regions, in spite of having formed a large gap., Paper accepted to the Astrophysical Journal Letters

International audience; We have completed our seasonal monitoring of hydrogen peroxide and water vapor on Mars using ground-based thermal imaging spectroscopy, by observing the planet in March 2014, when water vapor is maximum, and July 2014, when, according to photochemical models, hydrogen peroxide is expected to be maximum. Data have been obtained with the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted at the 3 m–Infrared Telescope Facility (IRTF) at Maunakea Observatory. Maps of HDO and H2O2 have been obtained using line depth ratios of weak transitions of HDO and H2O2 divided by CO2. The retrieved maps of H2O2 are in good agreement with predictions including a chemical transport model, for both the March data (maximum water vapor) and the July data (maximum hydrogen peroxide). The retrieved maps of HDO are compared with simulations by Montmessin et al. (2005, J. Geophys. Res., 110, 03006) and H2O maps are inferred assuming a mean martian D/H ratio of 5 times the terrestrial value. For regions of maximum values of H2O and H2O2, we derive, for March 1 2014 (Ls = 96°), H2O2 = 20+/−7 ppbv, HDO = 450 +/−75 ppbv (45 +/−8 pr-nm), and for July 3, 2014 (Ls = 156°), H2O2 = 30+/−7 ppbv, HDO = 375+/−70 ppbv (22+/−3 pr-nm). In addition, the new observations are compared with LMD global climate model results and we favor simulations of H2O2 including heterogeneous reactions on water-ice clouds.

We measured the $12.8\mu$m [NeII] line in the dwarf starburst galaxy He 2-10 with the high-resolution spectrometer TeXeS on the NASA IRTF. The data cube has diffraction-limited spatial resolution $\sim1^{\prime\prime}$ and total velocity resolution including thermal broadening of $\sim5$km/s. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the $M/R$ of the clusters and the $\simeq30-40$% star formation efficiencies the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature which we identify with the interface of the HII region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded HII regions with their environment., Comment: accepted to ApJ

International audience; We report the first detection of propane, C 3H 8, in Saturn's stratosphere. Observations taken on September 8, 2002 UT at NASA's IRTF using TEXES, show multiple emission lines due to the 748 cm -1nu band of C 3H 8. Using a line-by-line radiative transfer code, we are able to fit the data by scaling the propane vertical mixing ratio profile from the photochemical model of Moses et al. [2000. Icarus 143, 244-298]. Multiplicative factors of 0.7 and 0.65 are required to fit the -20° and -80° planetocentric latitude spectra. The resultant profiles are characterized by a 5 mbar mixing ratio of 2.7±0.8×10 at -20° and 2.5-0.8+1.7×10 at -80° latitude. These results suggest that the time scale for meridional circulation lies between the net photochemical lifetimes of C 2H 2 and C 3H 8, ≈30-600 years.

International audience; High-resolution infrared imaging spectroscopy of Mars has been achieved at the NASA Infrared Telescope Facility (IRTF) on June 19-21, 2003, using the Texas Echelon Cross Echelle Spectrograph (TEXES). The areocentric longitude was 206°. Following the detection and mapping of hydrogen peroxide H 2O 2 [Encrenaz et al., 2004. Icarus 170, 424-429], we have derived, using the same data set, a map of the water vapor abundance. The results appear in good overall agreement with the TES results and with the predictions of the Global Circulation Model (GCM) developed at the Laboratory of Dynamical Meteorology (LMD), with a maximum abundance of water vapor of 3±1.5×10(17±9 pr-mum). We have searched for CH 4 over the martian disk, but were unable to detect it. Our upper limits are consistent with earlier reports on the methane abundance on Mars. Finally, we have obtained new measurements of CO 2 isotopic ratios in Mars. As compared to the terrestrial values, these values are: ( 18O/ 17O)[M/E] = 1.03 ± 0.09; ( 13C/ 12C)[M/E] = 1.00 ± 0.11. In conclusion, in contrast with the analysis of Krasnopolsky et al. [1996. Icarus 124, 553-568], we conclude that the derived martian isotopic ratios do not show evidence for a departure from their terrestrial values.

High spectral and spatial resolution, mid-infrared fine structure line observations toward two ultracompact HII (UCHII) regions (G29.96 -0.02 and Mon R2) allow us to study the structure and kinematics of cometary UCHII regions. In our earlier study of Mon R2, we showed that highly organized mass motions accounted for most of the velocity structure in that UCHII region. In this work, we show that the kinematics in both Mon R2 and G29.96 are consistent with motion along an approximately paraboloidal shell. We model the velocity structure seen in our mapping data and test the stellar wind bow shock model for such paraboloidal like flows. The observations and the simulation indicate that the ram pressures of the stellar wind and ambient interstellar medium cause the accumulated mass in the bow shock to flow along the surface of the shock. A relaxation code reproduces the mass flow's velocity structure as derived by the analytical solution. It further predicts that the pressure gradient along the flow can accelerate ionized gas to a speed higher than that of the moving star. In the original bow shock model, the star speed relative to the ambient medium was considered to be the exit speed of ionized gas in the shell.

Using the Texas Echelon Cross Echelle Spectrograph (TEXES) we mapped emission in the H_2 v = 0-0 S(1) and S(2) lines toward the Orion Bar PDR at 2" resolution. We also observed H_2 v = 0-0 S(4) at selected points toward the front of the PDR. Our maps cover a 12" by 40" region of the bar where H_2 ro-vibrational lines are bright. The distributions of H_2 0-0 S(1), 0-0 S(2), and 1-0 S(1) line emission agree in remarkable detail. The high spatial resolution (0.002 pc) of our observations allows us to probe the distribution of warm gas in the Orion Bar to a distance approaching the scale length for FUV photon absorption. We use these new observational results to set parameters for the PDR models described in a companion paper (Draine et al. 2005, in prep). The best-fit model can account for the separation of the H_2 emission from the ionization front and the intensities of the ground state rotational lines as well as the 1-0 S(1) and 2-1 S(1) lines. This model requires significant adjustments to the commonly used values for the dust UV attenuation cross section and the photoelectric heating rate., 35 pages, 6 figures ApJ, accepted

International audience; Measurements of the vertical and latitudinal variations of temperature and C 2H 2 and C 2H 6 abundances in the stratosphere of Saturn can be used as stringent constraints on seasonal climate models, photochemical models, and dynamics. The summertime photochemical loss timescale for C 2H 6 in Saturn's middle and lower stratosphere ( ˜40-10,000 years, depending on altitude and latitude) is much greater than the atmospheric transport timescale; ethane observations may therefore be used to trace stratospheric dynamics. The shorter chemical lifetime for C 2H 2 ( ˜1-7 years depending on altitude and latitude) makes the acetylene abundance less sensitive to transport effects and more sensitive to insolation and seasonal effects. To obtain information on the temperature and hydrocarbon abundance distributions in Saturn's stratosphere, high-resolution spectral observations were obtained on September 13-14, 2002 UT at NASA's IRTF using the mid-infrared TEXES grating spectrograph. At the time of the observations, Saturn was at a L≈270°, corresponding to Saturn's southern summer solstice. The observed spectra exhibit a strong increase in the strength of methane emission at 1230 cm -1 with increasing southern latitude. Line-by-line radiative transfer calculations indicate that a temperature increase in the stratosphere of ≈10 K from the equator to the south pole between 10 and 0.01 mbar is implied. Similar observations of acetylene and ethane were also recorded. We find the 1.16 mbar mixing ratio of C 2H 2 at -1° and -83° planetocentric latitude to be 9.2-3.8+6.4×10 and 2.5-1.0+1.8×10, respectively. The C 2H 2 mixing ratio at 0.12 mbar is found to be 1.0-0.3+0.5×10 at -1° planetocentric latitude and 2.6-0.9+1.3×10 at -83° planetocentric latitude. The 2.3 mbar mixing ratio of C 2H 6 inferred from the data is 7.5-1.7+2.3×10 and 1.0-0.2+0.3×10 at -1° and -83° planetocentric latitude, respectively. Further observations, creating a time baseline, will be required to completely resolve the question of how much the latitudinal variations of C 2H 2 and C 2H 6 are affected by seasonal forcing and/or stratospheric circulation.

International audience; In July 1994, the Shoemaker-Levy 9 (SL9) impacts introduced hydrogen cyanide (HCN) to Jupiter at a well confined latitude band around -44°, over a range of specific longitudes corresponding to each of the 21 fragments (Bézard et al. 1997, Icarus 125, 94-120). This newcomer to Jupiter's stratosphere traces jovian dynamics. HCN rapidly mixed with longitude, so that observations recorded later than several months after impact witnessed primarily the meridional transport of HCN north and south of the impact latitude band. We report spatially resolved spectroscopy of HCN emission 10 months and 6 years following the impacts. We detect a total mass of HCN in Jupiter's stratosphere of 1.5±0.7×10 13 g in 1995 and 1.7±0.4×10 13 g in 2000, comparable to that observed several days following the impacts (Bézard et al. 1997, Icarus 125, 94-120). In 1995, 10 months after impact, HCN spread to -30° and -65° latitude (half column masses), consistent with a horizontal eddy diffusion coefficient of Kyy=2-3×10 10 cm 2 s -1. Six years following impact HCN is observed in the northern hemisphere, while still being concentrated at 44° south latitude. Our meridional distribution of HCN suggests that mixing occurred rapidly north of the equator, with Kyy=2-5×10 11 cm 2 s -1, consistent with the findings of Moreno et al. (2003, Planet. Space Sci. 51, 591-611) and Lellouch et al. (2002, Icarus 159, 112-131). These inferred eddy diffusion coefficients for Jupiter's stratosphere at 0.1-0.5 mbar generally exceed those that characterize transport on Earth. The low abundance of HCN detected at high latitudes suggests that, like on Earth, polar regions are dynamically isolated from lower latitudes.

We have detected the [S IV] 10.5 micron and [Ne II] 12.8 micron fine-structure lines in the halo population planetary nebula (PN) DdDm 1, and set upper limits on their intensities in the halo PN H 4-1. We also present new measurements of optical lines from various ions of S, Ne, O, and H for DdDm 1, based on a high-dispersion spectrum covering the spectral range 3800 A to 1 micron. These nebulae have similar O/H abundances, (O/H) = 1e-4, but S/H and Ne/H are about half an order of magnitude lower in H 4-1 than in DdDm 1; thus H 4-1 appears to belong to a more metal-poor population. This supports previous suggestions that PNe arising from metal-poor progenitor stars can have elevated oxygen abundances due to internal nucleosynthesis and convective dredge-up. It is generally accepted that high abundances of carbon in many PNe results from self-enrichment. To the extent that oxygen can also be affected, the use of nebular O/H values to infer the overall metallicity of a parent stellar population (for example, in external galaxies) may be suspect, particularly for low metallicities.

We report detections of pure rotation lines of OH and H2O in the K1.5 III red-giant star Arcturus (alpha Bootis) using high-resolution, infrared spectra covering the regions 806-822 cm-1 (12.2-12.4 um) and 884-923 cm-1 (10.8-11.3 um). Arcturus is the hottest star yet to show water-vapor features in its disk-averaged spectrum. We argue that the water vapor lines originate from the photosphere, albeit in the outer layers. We are able to predict the observed strengths of OH and H2O lines satisfactorily after lowering the temperature structure of the very outer parts of the photosphere (log tau_500=-3.8 and beyond) compared to a flux-constant, hydrostatic, standard MARCS model photosphere. Our new model is consistently calculated including chemical equilibrium and radiative transfer from the given temperature structure. Possible reasons for a temperature decrease in the outer-most parts of the photosphere and the assumed break-down of the assumptions made in classical model-atmosphere codes are discussed., To appear in ApJ. See also http://www.astro.uu.se/~ryde/ART/

NGC 4194 is a post-merger starburst known as The Medusa for its striking tidal features. We present here a detailed study of the structure and kinematics of ionized gas in the central 0.65 kpc of the Medusa. The data include radio continuum maps with resolution up to $0.18\arcsec$ (35 pc) and a $12.8\mu$m [NeII] data cube with spectral resolution $\sim4$\kms: the first {\it high resolution, extinction-free} observations of this remarkable object. The ionized gas has the kinematic signature of a core in solid-body rotation. The starburst has formed a complex of bright compact \HII~regions, probably excited by deeply embedded super star clusters, but none of these sources is a convincing candidate for a galactic nucleus. The nuclei of the merger partners that created the Medusa have not yet been identified., Comment: to appear in ApJ

We have mapped the central parsec of the H II region W33 in the infrared fine-structure lines of [Ne II] (12.8 ?m) and [Ar III] (8.99 ?m), and have measured spectra of [Ar II] (6.99 ?m) at selected locations. This is the first observation of the 6.99 ?m line from the ground. The spatial distribution of the infrared lines resembles that of the radio continuum, except for one region where the extinction is apparently very high (even at 12.8 ?m). The abundances of neon and argon in W33 are a factor of 4 lower than solar. We have analyzed the ratios of the mapped lines to derive the types of the exciting stars, their ages, and other features of the source. The cluster contains three distinct subsources, one of which appears to be a cometary and another a shell-like ultracompact H II region, although they are larger and less dense than most objects of this class. The stars are of types O6 to O7 and less than a few million years old. We suggest that star formation in this object has been proceeding simultaneously in at least three centers, and that the H II regions have not yet expanded to form one source.

High spectral resolution measurements of NH 3 and PH 3 lines on Jupiter in the 10.5- to 11.2-μm range are presented. Observations, recorded on January 21–23, 1991, cover the 10°–40°S latitude range and several longitudes including the Great Red Spot (GRS). Information on the temperature in the upper troposphere was retrieved from the continuum radiance at wavelengths around 12.8 and 17.8 μm. At all observed longitudes, the 200-mbar temperature field is minimum at latitudes of 20°–25°S near the location of the South Tropical Zone, in agreement with Voyager infrared retrievals. This minimum temperature is lower over the GRS than at other longitudes. The ammonia mixing ratio at ∼380 mbar is not significantly enhanced over the GRS. The phosphine abundance probed at ∼580 mbar is also not enhanced (within a precision of 10%), suggesting that this molecule is not a precursor of the reddish chromophores. The NH 3 abundance at 380 mbar varies highly with latitude and longitude, a possible consequence of the active jovian meteorology. At the resolution of our observations (∼8000 km), the NH 3 humidity at this altitude ranges between 15 and 100% throughout the available data set. Above the cloud tops, the NH 3 mixing ratio in the 240-mbar region reaches a maximum near 15°–18°S and decreases by a factor of ∼40 at latitudes 30°–35°S. This variation is not correlated with the 200-mbar temperature. It can be explained by a decrease of the eddy mixing coefficient near 240 mbar from ∼4000 to ≤400 cm 2 sec −1 between the two latitude ranges. The PH 3 mixing ratio near 580 mbar lies between 1.7 and 2.6 × 10 −7 in the observed regions. At all longitudes, PH 3 varies smoothly with latitude, decreasing by ∼30% from 10° to 35°S. This variation may also reflect a decrease in the strength of the eddy mixing near 580 mbar or at deeper levels in the atmosphere.

We report near-simultaneous interferometric measurements of the spectrum of Sagittarius A* over the 5-354 GHz range and single-dish observations that have yielded the first detection of Sgr A* at 850 GHz. We confirm that Sgr A*'s spectrum rises more steeply at short millimeter wavelengths than at centimeter wavelengths, leading to a near-millimeter/submillimeter excess that dominates its luminosity. Below 900 GHz, Sgr A*'s observed luminosity is 70 ± 30 L. A new upper limit to Sgr A*'s 24.3 μm flux, together with a compilation of other extant IR data, imply a far-infrared spectral turnover, which can result from either an intrinsic synchrotron cutoff or excess extinction near Sgr A*. If the former applies, Sgr A*'s total synchrotron luminosity is

Spatially resolved spectroscopy of the Shoemaker–Levy 9 (SL9) sites traces the dynamical evolution of cometary material, upwelled tropospheric gas, and compounds produced when the plume splashed back upon the atmosphere. The emissions of impact-produced stratospheric NH3, C2H4, and dust were imaged at NASA's Infrared Telescope Facility, with Irshell (the U. Texas mid-IR echelle spectrometer) 21 hr and 6, 11, and 12 days following the K impact. The images covered a ∼7 × 17″ region generally centered on the K site and were composed of 0.8 × 1 arcsec pixels, each containing a spectrum of resolution ∼15,000. We find evidence for two sources of NH3. Most of the stratospheric NH3resided at ∼20 mbar. A second reservoir existed above 1 mbar, with a column abundance ∼ 1 20 lower than that of the deeper source (2 ± 1 × 1017molecules cm−2above 40 mbar for the K site). The position of the high altitude NH3suggests that it rose and was quenched within the fireball and survived the splash. The 2 ± 1 × 1013g of low altitude NH3indicates that the K impact upwelled at least ∼2 × 1016g of jovian gas from Jupiter's troposphere. Its altitude coincides with the level where static stability is maximum. The NH3lineshape 12 days following impact indicates a gradual depletion of the high altitude source, which suggests that NH3was partially shielded from UV radiation. Enhanced continuum emission observed around 908 and 948 cm−1and not at wavenumbers outside the silicate feature is consistent with 8 ± 4 × 1012g of cometary dust residing in the plume fallback region. The total mass of C2H4was found to be 1 ± 0.3 × 1012g and remained constant within error limits throughout the observations. The compounds above 1 mbar displayed differing horizontal coverages consistent with each molecule's role in a ballistic plume, having a range of temperatures. Ammonia at 20 mbar spread out with time; however, its coverage was never as extensive as that of the dark material seen in HST images. In contrast, the dust, C2H4, and HCN (B. Bezardet al.1997,Icarus125,94–120), observed at significantly lower pressures than NH3, covered a broader spatial extent, similar to the coverage of the ejecta blanket observed by HST. Six days following impact, the dust and C2H4spread 7° eastward of NH3, similar to the dark particulates. The quiescent behavior of the NH3at 20 mbar in contrast to the zonal drift of the dust indicates the presence of winds above 1 mbar that are disconnected from those in the lower stratosphere.

We present high-resolution 8–14 μm observations of Shoemaker–Levy 9 sites conducted on July 20, 30, and 31 1994 UT at the NASA Infrared Telescope Facility. Stratospheric heating was detected from strong enhancements of methane emission near 8.1 μm over areas at least 15,000 km wide around the K site observed 23 hr after impact and around the L site 11 hr after impact. The intensity distribution between strong and weaker CH4lines implies that the stratospheric heating was primarily confined to pressures less than 500 μbar. The L site temperature increased by 80 ± 10 K at 5 μbar, but did not exceed 20 K around 1 mbar or 10 K around 10 mbar. The older K site was still 30 ± 5 K warmer than the surroundings at the 10-μbar level. The excess thermal energy stored in the upper jovian stratosphere was 3+3−1.5× 1026erg over the L site, and 2+2−1× 1026erg over the K site at the time of the observations. Comparison with numerical simulations indicates that a large fraction (>20%) of the kinetic energy of the L plume was transferred to the jovian atmosphere and not immediately radiated away. Acetylene line emission near 13.4 μm was enhanced over an area ∼18,000 km wide centered on the E site 2.6 days after impact. Radiative transfer models of this emission indicate temperatures 37 ± 7 K higher than nominal around 3 μbar. No such enhancement was seen in CH4spectral images, implying that the temperature perturbation did not significantly extend below the ∼20-μbar level. The H site observed simultaneously was 12 ± 5 K warmer than the surroundings 1.4 day after impact. C2H2lines were still slightly more intense over the K + W and Q1 sites on July 30 and 31, 8 to 10 days after impact. These observations can be interpreted either by temperature differences of about 13 and 10 K respectively in the 3-μbar region, or by an increase in the C2H2column density of 2.5–5 × 1017molecule cm−2. Emission from hydrogen cyanide lines around 13.4 μm was detected over all sites observed. The mass of HCN is about 2 × 1012g for the biggest plumes (K, L, G), 0.95 ± 0.5 × 1012g over the E site, and 0.45 ± 0.2 × 1012g over the H site. The total mass of HCN produced by all fragments is estimated to be 1.1 ± 0.4 × 1013g. A consistent interpretation of the different pieces of information available suggests that the H $cl10$plume was richer in dust than the E or A plume.

Infrared vibration-rotation lines can be valuable probes of interstellar and circumstellar molecules, especially symmetric molecules, which have no pure rotational transitions. But most such observations have been interpreted with an isothermal absorbing slab model, which leaves out important radiative transfer and molecular excitation effects. A more realistic non-LTE and non-isothermal radiative transfer model has been constructed. The results of this model are in much better agreement with the observations, including cases where lines in one branch of a vibration-rotation band are in absorption and another in emission. In general, conclusions based on the isothermal absorbing slab model can be very misleading, but the assumption of LTE may not lead to such large errors, particularly if the radiation field temperature is close to the gas temperature., Comment: 10 pages, 5 figures, ApJ in press