Search Publications
Non-LTE Inversions of the Mg II h & k and UV Triplet Lines
Leenaarts, Jorrit; Asensio Ramos, Andrés; de la Cruz Rodríguez, Jaime
The Mg II h & k lines are powerful diagnostics for studying the solar chromosphere. They have become particularly popular with the launch of the Interface Region Imaging Spectrograph (IRIS) satellite, and a number of studies that include these lines have lead to great progress in understanding chromospheric heating, in many cases thanks to the…
Photolytic Hazes in the Atmosphere of 51 Eri b
Morley, C. V.; Zahnle, K.; Moses, J. I. +1 more
We use a 1D model to address photochemistry and possible haze formation in the irradiated warm Jupiter, 51 Eridani b. The intended focus was to be carbon, but sulfur photochemistry turns out to be important. The case for organic photochemical hazes is intriguing but falls short of being compelling. If organic hazes form, they are likeliest to do s…
Data-driven Radiative Hydrodynamic Modeling of the 2014 March 29 X1.0 Solar Flare
Liu, Wei; Allred, Joel C.; Kleint, Lucia +2 more
Spectroscopic observations of solar flares provide critical diagnostics of the physical conditions in the flaring atmosphere. Some key features in observed spectra have not yet been accounted for in existing flare models. Here we report a data-driven simulation of the well-observed X1.0 flare on 2014 March 29 that can reconcile some well-known spe…
SN Refsdal: Photometry and Time Delay Measurements of the First Einstein Cross Supernova
Sharon, K.; Molino, A.; Zitrin, A. +16 more
We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) “Refsdal,” a gravitationally lensed SN at z = 1.488 ± 0.001 with multiple images behind the galaxy cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1-S4) exhibited a slow rise (over ∼150 days) to reach a broad peak brightness ar…
Infrared Color Selection of Massive Galaxies at z > 3
Daddi, E.; Elbaz, D.; Shu, X. +29 more
We introduce a new color selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H160 (H) and Infrared Array Camera (IRAC) 4.5 µm bands, specifically H-[4.5]\gt 2.25 mag. These galaxies, called “HIEROs,” include two major populations…
The Age of the Young Bulge-like Population in the Stellar System Terzan 5: Linking the Galactic Bulge to the High-z Universe
Dalessandro, E.; Massari, D.; Rich, R. M. +4 more
The Galactic bulge is dominated by an old, metal-rich stellar population. The possible presence and the amount of a young (a few gigayears old) minor component is one of the major issues debated in the literature. Recently, the bulge stellar system Terzan 5 was found to harbor three sub-populations with iron content varying by more than one order …
The Distance to M51
Dolphin, Andrew E.; Skillman, Evan D.; Berg, Danielle +2 more
Great investments of observing time have been dedicated to the study of nearby spiral galaxies with diverse goals ranging from understanding the star formation process to characterizing their dark matter distributions. Accurate distances are fundamental to interpreting observations of these galaxies, yet many of the best studied nearby galaxies ha…
BAHAMAS: New Analysis of Type Ia Supernovae Reveals Inconsistencies with Standard Cosmology
van Dyk, David A.; Shariff, Hikmatali; Jiao, Xiyun +1 more
We present results obtained by applying our BAyesian HierArchical Modeling for the Analysis of Supernova cosmology (BAHAMAS) software package to the 740 spectroscopically confirmed supernovae of type Ia (SNe Ia) from the “Joint Light-curve Analysis” (JLA) data set. We simultaneously determine cosmological parameters and standardization parameters,…
An Iron K Component to the Ultrafast Outflow in NGC 1313 X-1
Harrison, F. A.; Stern, D.; Fabian, A. C. +8 more
We present the detection of an absorption feature at E={8.77}-0.06+0.05 keV in the combined X-ray spectrum of the ultraluminous X-ray source NGC 1313 X-1 observed with XMM-Newton and NuSTAR, significant at the 3σ level. If associated with blueshifted ionized iron, the implied outflow velocity is ∼0.2c for Fe xxvi, or ∼0.25c f…
The MOSDEF Survey: Dynamical and Baryonic Masses and Kinematic Structures of Star-forming Galaxies at 1.4 ≤ z ≤ 2.6
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +11 more
We present {{H}}α gas kinematics for 178 star-forming galaxies at z∼ 2 from the MOSFIRE Deep Evolution Field survey. We have developed models to interpret the kinematic measurements from fixed-angle multi-object spectroscopy, using structural parameters derived from Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey Hubble Space Telesc…