Search Publications
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…
Cluster-formation in the Rosette molecular cloud at the junctions of filaments
Hill, T.; André, Ph.; Arzoumanian, D. +31 more
Aims: For many years feedback processes generated by OB-stars in molecular clouds, including expanding ionization fronts, stellar winds, or UV-radiation, have been proposed to trigger subsequent star formation. However, hydrodynamic models including radiation and gravity show that UV-illumination has little or no impact on the global dynamica…
A Revised Parallel-sequence Morphological Classification of Galaxies: Structure and Formation of S0 and Spheroidal Galaxies
Kormendy, John; Bender, Ralf
We update van den Bergh's parallel-sequence galaxy classification in which S0 galaxies form a sequence S0a-S0b-S0c that parallels the sequence Sa-Sb-Sc of spiral galaxies. The ratio B/T of bulge-to-total light defines the position of a galaxy in this tuning-fork diagram. Our classification makes one major improvement. We extend the S0a-S0b-S0c seq…
A magnified young galaxy from about 500 million years after the Big Bang
Donahue, Megan; Broadhurst, Tom; Kelson, Daniel D. +33 more
Re-ionization of the intergalactic medium occurred in the early Universe at redshift z ~ 6-11, following the formation of the first generation of stars. Those young galaxies (where the bulk of stars formed) at a cosmic age of less than about 500 million years (z <~ 10) remain largely unexplored because they are at or beyond the sensitivity limi…
Differential emission measures from the regularized inversion of Hinode and SDO data
Hannah, I. G.; Kontar, E. P.
Aims: To demonstrate the capabilities of regularized inversion to recover differential emission measures (DEMs) from multi-wavelength observations provided by telescopes such as Hinode and SDO.
Methods: We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse pr…
Using the Bright Ultrahard XMM-Newton survey to define an IR selection of luminous AGN based on WISE colours
Stern, D.; Barcons, X.; Blain, A. +7 more
We present a highly complete and reliable mid-infrared (MIR) colour selection of luminous active galactic nucleus (AGN) candidates using the 3.4, 4.6 and 12 µm bands of the Wide-field Infrared Survey Explorer (WISE) survey. The MIR colour wedge was defined using the wide-angle Bright Ultrahard XMM-Newton survey (BUXS), one of the largest com…