Search Publications
The MOSDEF Survey: Direct Observational Constraints on the Ionizing Photon Production Efficiency, ξ ion, at z ∼ 2
Siana, Brian; Shapley, Alice E.; Reddy, Naveen A. +11 more
We combine Hα and Hβ spectroscopic measurements and UV photometry for a sample of 673 galaxies from the MOSDEF survey to constrain hydrogen-ionizing photon production efficiencies ({ξ }ion}) at z = 1.4-2.6. We find < {log}({ξ }ion}/[{{{s}}}-1/{erg} {{{s}}}-1 {Hz}}-1])> = 25.06 (25.34), a…
Spectra of Hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory
Ellis, Richard; Filippenko, Alexei V.; Pan, Yen-Chen +20 more
Most Type I superluminous supernovae (SLSNe-I) reported to date have been identified by their high peak luminosities and spectra lacking obvious signs of hydrogen. We demonstrate that these events can be distinguished from normal-luminosity SNe (including Type Ic events) solely from their spectra over a wide range of light-curve phases. We use thi…
Age Determinations of the Hyades, Praesepe, and Pleiades via MESA Models with Rotation
Choi, Jieun; Conroy, Charlie; Dotter, Aaron +4 more
The Hyades, Praesepe, and Pleiades are well-studied stellar clusters that anchor important secondary stellar age indicators. Recent studies have shown that main sequence turn off based ages for these clusters may depend on the degree of rotation in the underlying stellar models. Rotation induces structural instabilities that can enhance the chemic…
The Milky Way Halo in Action Space
Myeong, G. C.; Evans, N. W.; Belokurov, V. +2 more
We analyze the structure of the local stellar halo of the Milky Way using ∼60000 stars with full phase space coordinates extracted from the SDSS-Gaia catalog. We display stars in action space as a function of metallicity in a realistic axisymmetric potential for the Milky Way Galaxy. The metal-rich population is more distended toward high radial a…
An Empirical Measurement of the Initial-Final Mass Relation with Gaia White Dwarfs
Rix, Hans-Walter; El-Badry, Kareem; Weisz, Daniel R.
We use data from Gaia’s second data release (DR2) to constrain the initial-final mass relation (IFMR) for field stars with initial masses 0.9 ≲ m in/M ⊙ ≲ 8. Precise parallaxes have revealed unprecedented substructure in the white dwarf (WD) cooling sequence on the color-magnitude diagram (CMD). Some of this substructure stem…
Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ∼ 2.5 Submillimeter Galaxies
Smail, Ian; Brandt, W. N.; Rybak, M. +17 more
We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ∼ 2-3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1-5 kpc (0.″1-0.″6). The velocity fields of our sources, traced by the 12CO(J = 3-2) emission, are consistent with disk rotation to the …
Determination of Differential Emission Measure from Solar Extreme Ultraviolet Images
Veronig, Astrid M.; Gan, Weiqun; Cheung, Mark C. M. +5 more
The Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) has been providing high-cadence, high-resolution, full-disk UV-visible/extreme ultraviolet (EUV) images since 2010, with the best time coverage among all the solar missions. A number of codes have been developed to extract plasma differential emission measures (DEM…
The R-Process Alliance: First Release from the Northern Search for r-process-enhanced Metal-poor Stars in the Galactic Halo
Grebel, Eva K.; Steinmetz, Matthias; Beers, Timothy C. +26 more
This paper presents the detailed abundances and r-process classifications of 126 newly identified metal-poor stars as part of an ongoing collaboration, the R-Process Alliance. The stars were identified as metal-poor candidates from the RAdial Velocity Experiment (RAVE) and were followed up at high spectral resolution (R ∼ 31,500) with the 3.5 m te…
The Kepler Light Curves of AGN: A Detailed Analysis
Howell, Steve B.; Gelino, Dawn M.; Boyd, Patricia T. +3 more
We present a comprehensive analysis of 21 light curves of Type 1 active galactic nuclei (AGN) from the Kepler spacecraft. First, we describe the necessity and development of a customized pipeline for treating Kepler data of stochastically variable sources like AGN. We then present the light curves, power spectral density functions (PSDs), and flux…
The Disk Substructures at High Angular Resolution Project (DSHARP). IV. Characterizing Substructures and Interactions in Disks around Multiple Star Systems
Wilner, David J.; Andrews, Sean M.; Guzmán, Viviana V. +11 more
To characterize the substructures induced in protoplanetary disks by the interaction between stars in multiple systems, we study the 1.25 mm continuum and the 12CO(J = 2-1) spectral line emission of the triple systems HT Lup and AS 205, at scales of ≈5 au, as part of the “Disk Substructures at High Angular Resolution Project” (DSHARP). …