Search Publications
CANDELS: Constraining the AGN-Merger Connection with Host Morphologies at z ~ 2
Bell, Eric F.; Giavalisco, Mauro; Grogin, Norman A. +35 more
Using Hubble Space Telescope/WFC3 imaging taken as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, we examine the role that major galaxy mergers play in triggering active galactic nucleus (AGN) activity at z ~ 2. Our sample consists of 72 moderate-luminosity (L X ~ 1042-44 erg s-1) AGNs …
Smooth(er) Stellar Mass Maps in CANDELS: Constraints on the Longevity of Clumps in High-redshift Star-forming Galaxies
Barro, Guillermo; Bell, Eric F.; Ferguson, Henry C. +22 more
We perform a detailed analysis of the resolved colors and stellar populations of a complete sample of 323 star-forming galaxies (SFGs) at 0.5 < z < 1.5 and 326 SFGs at 1.5 < z < 2.5 in the ERS and CANDELS-Deep region of GOODS-South. Galaxies were selected to be more massive than 1010 M ⊙ and have specific star for…
Evolution of Magnetic Field and Energy in a Major Eruptive Active Region Based on SDO/HMI Observation
Liu, Yang; Hayashi, Keiji; Sun, Xudong +4 more
We report the evolution of the magnetic field and its energy in NOAA active region 11158 over five days based on a vector magnetogram series from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). Fast flux emergence and strong shearing motion led to a quadrupolar sunspot complex that produced several major er…
Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function
Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +12 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…
The Flat Transmission Spectrum of the Super-Earth GJ1214b from Wide Field Camera 3 on the Hubble Space Telescope
Fortney, Jonathan J.; Désert, Jean-Michel; Charbonneau, David +7 more
Capitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instr…
Candels: The Evolution of Galaxy Rest-frame Ultraviolet Colors from z = 8 to 4
Papovich, Casey; Finkelstein, Steven L.; Dickinson, Mark +18 more
We study the evolution of galaxy rest-frame ultraviolet (UV) colors in the epoch 4 <~ z <~ 8. We use new wide-field near-infrared data in the Great Observatories Origins Deep Survey-South field from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble Ultra Deep Field (HUDF) 2009, and Early Release Science programs to s…
Keck Spectroscopy of Faint 3 < z < 8 Lyman Break Galaxies: Evidence for a Declining Fraction of Emission Line Sources in the Redshift Range 6 < z < 8
Richard, Johan; Stark, Daniel P.; Ellis, Richard S. +5 more
Using deep Keck spectroscopy of Lyman break galaxies selected from infrared imaging data taken with the Wide Field Camera 3 on board the Hubble Space Telescope, we present new evidence for a reversal in the redshift-dependent fraction of star-forming galaxies with detectable Lyman alpha (Lyα) emission in the redshift range 6.3 < z < 8.8. Our…
What Turns Galaxies Off? The Different Morphologies of Star-forming and Quiescent Galaxies since z ~ 2 from CANDELS
Papovich, Casey; Bell, Eric F.; Giavalisco, Mauro +21 more
We use HST/WFC3 imaging from the CANDELS Multi-Cycle Treasury Survey, in conjunction with the Sloan Digital Sky Survey, to explore the evolution of galactic structure for galaxies with stellar masses >3 × 1010 M ⊙ from z = 2.2 to the present epoch, a time span of 10 Gyr. We explore the relationship between rest-frame optic…
The Characteristic Star Formation Histories of Galaxies at Redshifts z ~ 2-7
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +3 more
A large sample of spectroscopically confirmed star-forming galaxies at redshifts 1.4 <= z spec <= 3.7, with complementary imaging in the near- and mid-IR from the ground and from the Hubble Space Telescope and Spitzer Space Telescope, is used to infer the average star formation histories (SFHs) of typical galaxies from z ~ 2 to 7.…
Lower-luminosity Galaxies Could Reionize the Universe: Very Steep Faint-end Slopes to the UV Luminosity Functions at z >= 5-8 from the HUDF09 WFC3/IR Observations
Trenti, M.; Oesch, P. A.; Carollo, C. M. +7 more
The HUDF09 data are the deepest near-IR observations ever, reaching to 29.5 mag. Luminosity functions (LFs) from these new HUDF09 data for 132 z ~ 7 and z ~ 8 galaxies are combined with new LFs for z ~ 5-6 galaxies and the earlier z ~ 4 LF to reach to very faint limits (<0.05 L* z = 3). The faint-end slopes α are steep: -1.79 ± 0.12 …