Search Publications
All the PAHs: An AKARI-Spitzer Cross-archival Spectroscopic Survey of Aromatic Emission in Galaxies
Baba, Shunsuke; Imanishi, Masatoshi; Lai, Thomas S. -Y. +2 more
We present a large sample of 2.5-38 µm galaxy spectra drawn from a cross-archival comparison in the AKARI-Spitzer Extragalactic Spectral Survey, and investigate a subset of 113 star-forming galaxies with prominent polycyclic aromatic hydrocarbon (PAH) emission spanning a wide range of star formation properties. With AKARI's extended 2.5-5 &m…
unWISE tomography of Planck CMB lensing
Ferraro, Simone; Schlafly, Edward F.; White, Martin +1 more
CMB lensing tomography, or the cross-correlation between CMB lensing maps and large-scale structure tracers over a well-defined redshift range, has the potential to map the amplitude and growth of structure over cosmic time, provide some of the most stringent tests of gravity, and break important degeneracies between cosmological parameters. In th…
Star cluster formation in the most extreme environments: insights from the HiPEEC survey
Östlin, G.; Larsen, S. S.; Sabbi, E. +14 more
We present the Hubble imaging Probe of Extreme Environments and Clusters (HiPEEC) survey. We fit HST NUV to NIR broad-band and H α fluxes to derive star cluster ages, masses, and extinctions and determine the star formation rate (SFR) of six merging galaxies. These systems are excellent laboratories to trace cluster formation under extreme gas phy…
The High-energy Radiation Environment around a 10 Gyr M Dwarf: Habitable at Last?
Loyd, R. O. Parke; Kowalski, Adam F.; Brown, Alexander +20 more
Recent work has demonstrated that high levels of X-ray and UV activity on young M dwarfs may drive rapid atmospheric escape on temperate, terrestrial planets orbiting within the habitable zone. However, secondary atmospheres on planets orbiting older, less active M dwarfs may be stable and present more promising candidates for biomarker searches. …
How comets work: nucleus erosion versus dehydration
Blum, J.; Güttler, C.; Gundlach, B. +3 more
We develop an activity model based on ice sublimation and gas diffusion inside cm-sized pebbles making-up a cometary nucleus. Our model explains cometary activity assuming no free parameters and fixing the nucleus surface temperature Ts, its gradient below the nucleus surface at thermal equilibrium, the pressure inside the porous pebble…
Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA
Kobayashi, Chiaki; Nomoto, Ken'ichi; Ireland, Michael +3 more
We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based Solar Mass Ejection Imager instrument prior to Betelgeuse's …
Observations of Disequilibrium CO Chemistry in the Coldest Brown Dwarfs
Fortney, Jonathan J.; Marley, Mark S.; Freedman, Richard S. +10 more
Cold brown dwarfs are excellent analogs of widely separated, gas giant exoplanets, and provide insight into the potential atmospheric chemistry and physics we may encounter in objects to be discovered by future direct imaging surveys. We present a low-resolution, R ∼ 300, M-band spectroscopic sequence of seven brown dwarfs with effective temperatu…
Neutron-capture elements in dwarf galaxies. III. A homogenized analysis of 13 dwarf spheroidal and ultra-faint galaxies
Hansen, C. J.; Skúladóttir, Á.; Grebel, E. K. +3 more
Context. We present a large homogeneous set of stellar parameters and abundances across a broad range of metallicities, involving 13 classical dwarf spheroidal (dSph) and ultra-faint dSph (UFD) galaxies. In total, this study includes 380 stars in Fornax, Sagittarius, Sculptor, Sextans, Carina, Ursa Minor, Draco, Reticulum II, Bootes I, Ursa Major …
Nebular spectra of 111 Type Ia supernovae disfavour single-degenerate progenitors
Kochanek, C. S.; Galbany, L.; Kumar, S. +15 more
We place statistical constraints on Type Ia supernova (SN Ia) progenitors using 227 nebular-phase spectra of 111 SNe Ia. We find no evidence of stripped companion emission in any of the nebular-phase spectra. Upper limits are placed on the amount of mass that could go undetected in each spectrum using recent hydrodynamic simulations. With these nu…
Reviving old controversies: is the early Galaxy flat or round?. Investigations into the early phases of the Milky Way's formation through stellar kinematics and chemical abundances
Bonifacio, P.; Caffau, E.; Spite, M. +4 more
We analysed a set of very metal-poor stars, for which accurate chemical abundances have been obtained as part of the ESO Large Program "First stars" in the light of the Gaia DR2 data. The kinematics and orbital properties of the stars in the sample show they probably belong to the thick disc, partially heated to halo kinematics, and to the accrete…