Search Publications
Three Radial Gaps in the Disk of TW Hydrae Imaged with SPHERE
Quanz, S. P.; Avenhaus, H.; Dominik, C. +24 more
We present scattered light images of the TW Hya disk performed with the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument in Polarimetric Differential Imaging mode at 0.63, 0.79, 1.24, and 1.62 µm. We also present H2/H3-band angular differential imaging (ADI) observations. Three distinct radial depressions in the polarized int…
Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies
Leitherer, Claus; Wofford, Aida; Tilvi, V. +7 more
We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O III]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas …
Gaia Reveals a Metal-rich, in situ Component of the Local Stellar Halo
Conroy, Charlie; Bonaca, Ana; Hopkins, Philip F. +2 more
We use the first Gaia data release, combined with the RAVE and APOGEE spectroscopic surveys, to investigate the origin of halo stars within ≲ 3 kpc from the Sun. We identify halo stars kinematically as moving at a relative speed of at least 220 km s-1 with respect to the local standard of rest. These stars are generally less metal-rich …
PS16dtm: A Tidal Disruption Event in a Narrow-line Seyfert 1 Galaxy
Berger, E.; Chornock, R.; Nicholl, M. +6 more
We present observations of PS16dtm (also known as SN 2016ezh), a luminous transient that occurred at the nucleus of a narrow-line Seyfert 1 galaxy hosting a 106 M ⊙ black hole. The light curve shows that PS16dtm exhibited a plateau phase for ∼100 days, during which it showed no color evolution, maintained a blackbody temperat…
The Constant Average Relationship between Dust-obscured Star Formation and Stellar Mass from z = 0 to z = 2.5
Casey, Caitlin M.; Cybulski, Ryan; Yun, Min S. +3 more
The total star formation budget of galaxies consists of the sum of the unobscured star formation, as observed in the rest-frame ultraviolet (UV), together with the obscured component that is absorbed and re-radiated by dust grains in the infrared. We explore how the fraction of obscured star formation depends on stellar mass for mass-complete samp…
FRB 121102 Is Coincident with a Star-forming Region in Its Host Galaxy
Ransom, S. M.; Chatterjee, S.; Cordes, J. M. +16 more
We present optical, near-infrared, and mid-infrared imaging of the host galaxy of FRB 121102 with the Gemini North telescope, the Hubble Space Telescope, and the Spitzer Space Telescope. The FRB 121102 host galaxy is resolved, revealing a bright star-forming region located in the outskirts of the irregular, low-metallicity dwarf galaxy. The star-f…
The Open Flux Problem
Liu, Y.; Arge, C. N.; Henney, C. J. +9 more
The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational c…
The Stellar Initial Mass Function in Early-type Galaxies from Absorption Line Spectroscopy. III. Radial Gradients
van Dokkum, Pieter; Romanowsky, Aaron J.; Conroy, Charlie +2 more
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to that of the Milky Way. Here we study the radial variation of the IMF within such galaxies, using a combination of high-quality Keck spectroscopy and a new suite of stellar population synthesis models that cover…
The Green Bank Ammonia Survey: First Results of NH3 Mapping of the Gould Belt
Caselli, Paola; Di Francesco, James; Rosolowsky, Erik +23 more
We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with {A}{{V}}≳ 7 mag visible from the northern hemisphere in emission from NH3 and other key molecular tracers. T…
Magnetic Properties of Solar Active Regions That Govern Large Solar Flares and Eruptions
Toriumi, Shin; Harra, Louise K.; Nagashima, Kaori +2 more
Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim of understanding the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with Geostationary Orbiting Environmental Satellite levels of ≥M5.0 within 45° from disk center between…