W33A is a well-known example of a high-mass young stellar object showing evidence of a circumstellar disc. We revisited the K-band NIFS/Gemini North observations of the W33A protostar using principal components analysis tomography and additional post-processing routines. Our results indicate the presence of a compact rotating disc based on the kinematics of the CO absorption features. The position...

Astrophysical phenomena occur on a range of timescales, and to properly characterize them, observations must be made at appropriate intervals on instrumentation determined by the scientific goals of the study. The traditional model of scheduling telescope time in blocks of consecutive nights and requiring the investigators to operate the instrument (either in person or remotely) is not optimal for this science. A queue-scheduled approach to time allocation can relieve the personal and financial burden of interactive observing runs. This is particularly powerful when requests for observations can be made through a programmatic interface, which provides not just a convenient tool for all astronomy programs, but also the opportunity to build fully automated observing programs. This will be an essential component of projects making follow-up observations for modern surveys that produce millions of alerts per night, as much of the science return will depend upon obtaining classification and characterization data rapidly and efficiently, as well as for coordination of observations across multiple facilities. The AEON Network is an initiative to build a programmatically accessible, queue-scheduled and user driven network of telescopes ideal for modern astronomical observing programs.

DESI (Dark Energy Spectropic Instrument) is a Stage IV ground-based dark energy experiment that will study baryon acoustic oscillations and the growth of structure through redshift-space distortions with a wide-area galaxy and quasar redshift survey. The DESI instrument is a robotically-actuated, fiber-fed spectrograph capable of taking up to 5,000 simultaneous spectra over a wavelength range from 360 nm to 980 nm. The fibers feed ten three-arm spectrographs with resolution R= λ/Δλ between 2000 and 5500, depending on wavelength. The DESI instrument will be used to conduct a five-year survey designed to cover 14,000 deg^2. This powerful instrument will be installed at prime focus on the 4-m Mayall telescope in Kitt Peak, Arizona, along with a new optical corrector, which will provide a three-degree diameter field of view. The DESI collaboration will also deliver a spectroscopic pipeline and data management system to reduce and archive all data for eventual public use.

In this paper we present the results of a mid-infrared study of G49.5-0.4, or W51A, part of the massive starbirth complex W51. Combining public data from the Spitzer IRAC camera, and Gemini mid-infrared camera T-ReCS at 7.73, 9.69, 12.33, and 24.56 mu m, with a spatial resolution of similar to 0.'' 5, we have identified the mid-infrared counterparts of eight ultracompact H II regions, showing that two radio sources are deeply embedded in molecular clouds and another is a cloud of ionized gas. From the T-ReCS data we have unveiled the central core of the W51 region, revealing massive young stellar candidates. We modeled the spectral energy distribution of the detected sources. The results suggest that the embedded objects are sources with spectral types ranging from B3 to O5, but the majority of the fits indicate stellar objects with B1 spectral types. We also present an extinction map of IRS 2, showing that a region with lower extinction corresponds to the region where a proposed jet of gas has impacted the foreground cloud. From this map, we also derived the total extinction toward the enigmatic source IRS 2E, which amounts to similar to 60 mag in the V band. We calculated the color temperature due to thermal emission of the circumstellar dust of the detected sources; the temperatures are in the interval of similar to 100-150 K, which corresponds to the emission of dust located at 0.1 pc from the central source. Finally, we show a possible mid-infrared counterpart of a detected source at millimeter wavelengths that was found by Zapata et al. to be a massive young stellar object undergoing a high accretion rate.

The young stellar cluster Westerlund 1 (Wd 1: l = 339 degrees 6, b = -0.degrees 4) is one of the most massive in the local Universe, but accurate parameters are pending on better determination of its extinction and distance. Based on our photometry and data collected from other sources, we have derived a reddening law for the cluster line-of-sight representative of the Galactic plane (-5 degrees < b <+5 degrees) in the window 0.4-4.8 mu m: The power-law exponent alpha = 2.13 +/- 0.08 is much steeper than those published a decade ago (1.6-1.8) and our index R-V = 2.50 +/- 0.04 also differs from them, but in very good agreement with recent works based on deep surveys in the inner Galaxy. As a consequence, the total extinction A(Ks) = 0.74 +/- 0.08 (A(V) = 11.40 +/- 2.40) is substantially smaller than previous results (0.91-1.13), part of which (A(Ks) = 0.63 or A(V) = 9.66) is from the interstellar medium. The extinction in front of the cluster spans a range of Delta A(V) similar to 8.7 with a gradient increasing from SW to NE across the cluster face, following the same general trend of warm dust distribution. The map of the J - Ks colour index also shows a trend of reddening in this direction. We measured the equivalent width of the diffuse interstellar band at 8620 angstrom(the 'GAIA DIB') for Wd 1 cluster members and derived the relation A(Ks) = 0.612 EW - 0.191 EW2. This extends the Munari et al. relation, valid for EB-V < 1, to the non-linear regime (A(V) > 4).

We present an analysis of the stellar kinematics of the Large Magellanic Cloud (LMC), based on several thousand spectra obtained with Hydra-CTIO of massive red supergiants, oxygen-rich and carbon-rich AGB stars, and other giants. We have used the stellar velocities to measure the rotation curve of the LMC, which we find to have an amplitude of 87 +/- 5 km s(-1), a value that is in agreement with all of the available kinematic tracers. Our data also reveal a population of outliers, comprising similar to 5% of the sample, that have line-of-sight velocities that apparently oppose the sense of rotation of the LMC disk. We show that these outliers likely represent stars that were captured by the LMC from the Small Magellanic Cloud (SMC). The capture of these SMC stars and gas by the LMC may have been the trigger for the intense star formation that we now see in 30 Doradus, the most active star formation complex in the nearby universe, and may explain the detection of LMC microlensing events found by the MACHO and OGLE projects.

We present the results from a survey, designed to investigate the accretion process of massive young stellar objects (MYSOs) through near-infrared narrow-band imaging using the H-2 nu=1-0 S(1) transition filter. A sample of 353 MYSO candidates was selected from the Red MSX Source survey using photometric criteria at longer wavelengths (infrared and submillimetre) and chosen with positions throughout the Galactic plane. Our survey was carried out at the Southern Astrophysical Research Telescope Telescope in Chile and Canada-France-Hawaii Telescope in Hawaii covering both hemispheres. The data reveal that extended H-2 emission is a good tracer of outflow activity, which is a signpost of accretion process on young massive stars. Almost half of the sample exhibit extended H-2 emission and 74 sources (21 per cent) have polar morphology, suggesting collimated outflows. The polar-like structures are more likely to appear on radio-quiet sources, indicating these structures occur during the pre-UCH II phase. We also found an important fraction of sources associated with fluorescent H-2 diffuse emission that could be due to a more evolved phase. The images also indicate only similar to 23 per cent (80) of the sample is associated with extant (young) stellar clusters. These results support the scenario in which massive stars are formed by accretion discs, since the merging of low-mass stars would not produce outflow structures.

Formation of massive stars (M > 8 M-circle dot) is still not well understood and lacks of observational constraints. We observed 7 MYSO candidates using the NIFS spectrometer at Gemini North Telescope to study the accretion process at high angular resolution (similar to 50 mas) and very closer to the central star. Preliminary results for 2 sources have revealed circumstellar structures traced by Brackett-Gamma, CO lines and extended H-2 emission. Both sources present kinematics in the CO absorption lines, suggesting rotating structures. The next step will derive the central mass of each source by applying a keplerian model for these CO features.

We present preliminary results from a survey of molecular H-2 (2.12 mu m) emission in massive young stellar objects (MYSO) candidates selected from the Red MSX Source survey. We observed 354 MYSO candidates through the H-2 S(1) 1-0 transition (2.12 mu m) and an adjacent continuum narrow-band filters using the Spartan/SOAR and WIRCam/CFHT cameras. The continuum-subtracted H-2 maps were analyzed and extended H-2 emission was found in 50% of the sample (178 sources), and 38% of them (66) have polar morphology, suggesting collimated outflows. The polar-like structures are more likely to be driven on radio-quiet sources, indicating that these structures occur during the pre-ultra compact HII phase. We analyzed the continuum images and found that 54% (191) of the sample displayed extended continuum emission and only similar to 23% (80) were associated to stellar clusters. The extended continuum emission is correlated to the H-2 emission and those sources within stellar clusters does display diffuse H-2 emission, which may be due to fluorescent H-2 emission. These results support the accretion scenario for massive star formation, since the merging of low-mass stars would not produce jet-like structures. Also, the correlation between jet-like structures and radio-quiet sources indicates that higher inflow rates are required to form massive stars in a typical timescale less than 10(5) years.

K-band spectra are presented for a sample of 39 Spitzer IRS SAGE-Spec sources in the Large Magellanic Cloud. The spectra exhibit characteristics in very good agreement with their positions in the near infrared - Spitzer color-magnitude diagrams and their properties as deduced from the Spitzer IRS spectra. Specifically, the near infrared spectra show strong atomic and molecular features representative of oxygen-rich and carbon-rich asymptotic giant branch stars, respectively. A small subset of stars were chosen from the luminous and red extreme "tip" of the color magnitude diagram. These objects have properties consistent with dusty envelopes but also cool, carbon-rich "stellar" cores. Modest amounts of dust mass loss combine with the stellar spectral energy distribution to make these objects appear extreme in their near infrared and mid infrared colors. One object in our sample, HV 915, a known post asymptotic giant branch star of the RV Tau type exhibits CO 2.3 micron band head emission consistent with previous work that demonstrates the object has a circumstellar disk.

The Dark Energy Spectroscopic Instrument (DESI) is a massively multiplexed fiber-fed spectrograph that will make the next major advance in dark energy in the timeframe 2018-2022. On the Mayall telescope, DESI will obtain spectra and redshifts for at least 18 million emission-line galaxies, 4 million luminous red galaxies and 3 million quasi-stellar objects, in order to: probe the effects of dark energy on the expansion history using baryon acoustic oscillations (BAO), measure the gravitational growth history through redshift-space distortions, measure the sum of neutrino masses, and investigate the signatures of primordial inflation. The resulting 3-D galaxy maps at z<2 and Lyman-alpha forest at z>2 will make 1%-level measurements of the distance scale in 35 redshift bins, thus providing unprecedented constraints on cosmological models.

This document summarizes the results of a community-based discussion of the potential science impact of the Mayall+BigBOSS highly multiplexed multi-object spectroscopic capability. The KPNO Mayall 4m telescope equipped with the DOE- and internationally-funded BigBOSS spectrograph offers one of the most cost-efficient ways of accomplishing many of the pressing scientific goals identified for this decade by the "New Worlds, New Horizons" report. The BigBOSS Key Project will place unprecedented constraints on cosmological parameters related to the expansion history of the universe. With the addition of an open (publicly funded) community access component, the scientific impact of BigBOSS can be extended to many important astrophysical questions related to the origin and evolution of galaxies, stars, and the IGM. Massive spectroscopy is the critical missing ingredient in numerous ongoing and planned ground- and space-based surveys, and BigBOSS is unique in its ability to provide this to the US community. BigBOSS data from community-led projects will play a vital role in the education and training of students and in maintaining US leadership in these fields of astrophysics. We urge the NSF-AST division to support community science with the BigBOSS multi-object spectrograph through the period of the BigBOSS survey in order to ensure public access to the extraordinary spectroscopic capability.

We present chemical abundances in a sample of luminous cool stars located within 50 pc of the Galactic Center. Abundances of C, N, O, Ca and Fe are derived using high-resolution infrared spectra in the H- and K- bands. We report solar iron abundance, enhanced alpha element abundances, and CN-cycle mixed material in the atmospheres of these evolved stars.

We present a near-infrared study of the stellar content of 35 H ii regions in the Galactic plane, 24 of which have been classified as giant H ii regions. We have selected these optically obscured star-forming regions from the catalogues of Russeil, Conti & Crowther and Bica et al. In this paper, we have used the near-infrared domain J-, H- and K-s-band colour images to visually inspect the sample. Also, we have used colour-colour and colour-magnitude diagrams to indicate ionizing star candidates, as well as the presence of young stellar objects such as classical T Tauri stars and massive young stellar objects (MYSOs). We have obtained Spitzer Infrared Array Camera images for each region to help further characterize them. Spitzer and near-infrared morphology were used to place each cluster in an evolutionary phase of development. Spitzer photometry was also used to classify the MYSOs. A comparison of the main sequence in the colour-magnitude diagrams for each observed cluster was used to infer whether or not the cluster kinematic distance is consistent with brightnesses of the stellar sources. We find qualitative agreement for a dozen of the regions, but about half the regions have near-infrared photometry that suggests they may be closer than the kinematic distance. A significant fraction of these already have spectrophotometric parallaxes that support smaller distances. These discrepancies between kinematic and spectrophotometric distances are not a result of the spectrophotometric methodologies, as independent non-kinematic measurements are in agreement with the spectrophotometric results. For instance, the trigonometric parallaxes of star-forming regions were collected from the literature and show the same effect of smaller distances when compared to the kinematic results. In our sample of H ii regions, most of the clusters are evident in the near-infrared images. Finally, it is possible to distinguish among qualitative evolutionary stages for these objects.