Brenda L. Frye, Mairead Hurley, David. V. Bowen, Gerhardt Meurer, Keren Sharon, + 4 more

We take advantage of gravitational lensing amplification by Abell 1689 (z=0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i_775=27.3 via slitless grism spectroscopy. One ELG (at z=0.7895) is very bright owing to lensing magnification by a factor of ~4.5. Several Balmer emission lines detected from ground-based follow-up spectroscopy signal the onset of a major starburst for ...

Adam Schneider, Carl Melis, Inseok Song

We assess the current membership of the nearby, young TW Hydrae Association and examine newly proposed members with the Wide-field Infrared Survey Explorer (WISE) to search for infrared excess indicative of circumstellar disks. Newly proposed members TWA 30A, TWA 30B, TWA 31, and TWA 32 all show excess emission at 12 and 22 \mum providing clear evidence for substantial dusty circumstellar disks around these low-mass, ~8 Myr old stars that were previously shown to likely be accreting from circum...

Michiel Lambrechts, Anders Johansen

The observed lifetimes of gaseous protoplanetary discs place strong constraints on gas and ice giant formation in the core accretion scenario. The approximately 10-Earth-mass solid core responsible for the attraction of the gaseous envelope has to form before gas dissipation in the protoplanetary disc is completed within 1-10 million years. Building up the core by collisions between km-sized planetesimals fails to meet this time-scale constraint, especially at wide stellar separations. Nonethel...

Scott F. Daniel, Andrew J. Connolly, Jeff Schneider

We consider the problem of inferring constraints on a high-dimensional parameter space with a computationally expensive likelihood function. Markov chain Monte Carlo (MCMC) methods offer significant improvements in efficiency over grid-based searches and are easy to implement in a wide range of cases. However, MCMCs offer few guarantees that all of the interesting regions of parameter space are explored. We propose a machine learning algorithm that improves upon the performance of MCMC by intel...

M. Lendl, D. R. Anderson, A. Collier-Cameron, A. P. Doyle, M. Gillon, + 14 more

We report the discovery of two new transiting planets from the WASP survey. WASP-42 b is a 0.500 +- 0.035 M_J planet orbiting a K1 star at a separation of 0.0548 +- 0.0017 AU with a period of 4.9816872 +- 0.0000073 days. The radius of WASP-42 is 1.080 +- 0.057 R_J while its equilibrium temperature is T_eq = 995 +- 34 K. We detect some evidence of a small but non-zero eccentricity of e = 0.060 +- 0.013. WASP-49 b is a 0.378 +- 0.027 M_J planet around an old G6 star. It has a period of 2.7817387 ...

Robert A. Wittenmyer, J. Horner, M. Tuomi, G. S. Salter, C. G. Tinney, + 9 more

We report the detection of two new planets from the Anglo-Australian Planet Search. These planets orbit two stars each previously known to host one planet. The new planet orbiting HD 142 has a period of 6005\pm427 days, and a minimum mass of 5.3M_Jup. HD142c is thus a new Jupiter analog: a gas-giant planet with a long period and low eccentricity (e = 0.21 \pm 0.07). The second planet in the HD 159868 system has a period of 352.3\pm1.3 days, and m sin i=0.73\pm0.05 M_Jup. In both of these system...

Aleksandar M. Diamond-Stanic, John Moustakas, Christy A. Tremonti, Alison L. Coil, Ryan C. Hickox, + 3 more

We present the discovery of compact, obscured star formation in galaxies at z 0.6 that exhibit >1000 km/s outflows. Using optical morphologies from the Hubble Space Telescope and infrared photometry from the Wide-field Infrared Survey Explorer, we estimate star formation rate (SFR) surface densities that approach Sigma_SFR 3000 Msun/yr/kpc^2, comparable to the Eddington limit from radiation pressure on dust grains. We argue that feedback associated with a compact starburst in the form of rad...

J. T. Wright, G. W. Marcy, A. W. Howard, John Asher Johnson, T. Morton, + 1 more

We determine the fraction of F, G, and K dwarfs in the Solar Neighborhood hosting hot jupiters as measured by the California Planet Survey from the Lick and Keck planet searches. We find the rate to be 1.2\pm0.38%, which is consistent with the rate reported by Mayor et al. (2011) from the HARPS and CORALIE radial velocity surveys. These numbers are more than double the rate reported by Howard et al. (2011) for Kepler stars and the rate of Gould et al. (2006) from the OGLE-III transit search, ho...

J. Davy Kirkpatrick, Christopher R. Gelino, Michael C. Cushing, Gregory N. Mace, Roger L. Griffith, + 10 more

We present the discovery of another seven Y dwarfs from the Wide-field Infrared Survey Explorer (WISE). Using these objects, as well as the first six WISE Y dwarf discoveries from Cushing et al., we further explore the transition between spectral types T and Y. We find that the T/Y boundary roughly coincides with the spot where the J-H colors of brown dwarfs, as predicted by models, turn back to the red. Moreover, we use preliminary trigonometric parallax measurements to show that the T/Y bound...