Search Publications
The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints
van Dokkum, Pieter; Conroy, Charlie; Newman, Andrew B. +2 more
We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported…
Alignment between Protostellar Outflows and Filamentary Structure
Bourke, Tyler L.; Myers, Philip C.; Dunham, Michael M. +13 more
We present new Submillimeter Array (SMA) observations of CO(2-1) outflows toward young, embedded protostars in the Perseus molecular cloud as part of the Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) survey. For 57 Perseus protostars, we characterize the orientation of the outflow angles and compare them with the orien…
Fundamental Physics with the Hubble Frontier Fields: Constraining Dark Matter Models with the Abundance of Extremely Faint and Distant Galaxies
Castellano, M.; Grazian, A.; Menci, N. +4 more
We show that the measured abundance of ultra-faint lensed galaxies at z≈ 6 in the Hubble Frontier Fields (HFF) provides stringent constraints on the parameter space of (I) dark matter models based on keV sterile neutrinos; (II) “fuzzy” wavelike dark matter models, based on Bose-Einstein condensates of ultra-light particles. For the case of sterile…
The Progenitor and Early Evolution of the Type IIb SN 2016gkg
Lundqvist, P.; Gal-Yam, A.; Smith, M. +24 more
We report initial observations and analysis on the Type IIb SN 2016gkg in the nearby galaxy NGC 613. SN 2016gkg exhibited a clear double-peaked light curve during its early evolution, as evidenced by our intensive photometric follow-up campaign. SN 2016gkg shows strong similarities with other Type IIb SNe, in particular, with respect to the He I e…
Two-dimensional Radiative Magnetohydrodynamic Simulations of Partial Ionization in the Chromosphere. II. Dynamics and Energetics of the Low Solar Atmosphere
Martínez-Sykora, Juan; De Pontieu, Bart; Nóbrega-Siverio, Daniel +3 more
We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code. We have extended the code capabilities implementing ion-neutral interaction effects using the generalized Ohm’s law, I.e., we include the Hall term and the ambipolar diffusion (Pe…
AGN Populations in Large-volume X-Ray Surveys: Photometric Redshifts and Population Types Found in the Stripe 82X Survey
Kirkpatrick, Allison; Nandra, Kirpal; Marchesi, Stefano +16 more
Multiwavelength surveys covering large sky volumes are necessary to obtain an accurate census of rare objects such as high-luminosity and/or high-redshift active galactic nuclei (AGNs). Stripe 82X is a 31.3 X-ray survey with Chandra and XMM-Newton observations overlapping the legacy Sloan Digital Sky Survey Stripe 82 field, which has a rich invest…
The GOODS-N Jansky VLA 10 GHz Pilot Survey: Sizes of Star-forming µJY Radio Sources
Dickinson, Mark; Weiner, Benjamin J.; Inami, Hanae +5 more
Our sensitive ({σ }{{n}}≈ 572 {nJy} {{beam}}-1), high-resolution (FWHM {θ }1/2=0\buildrel{\prime\prime}\over{.} 22≈ 2 {kpc} {at} z≳ 1), 10 GHz image covering a single Karl G. Jansky Very Large Array (VLA) primary beam (FWHM {{{\Theta }}}1/2≈ 4\buildrel{ \prime}\over{.} 25) in the GOODS-N field contains 3…
The Carnegie-Chicago Hubble Program. II. The Distance to IC 1613: The Tip of the Red Giant Branch and RR Lyrae Period-luminosity Relations
Madore, Barry F.; Freedman, Wendy L.; Beaton, Rachael L. +8 more
IC 1613 is an isolated dwarf galaxy within the Local Group. Low foreground and internal extinction, low metallicity, and low crowding make it an invaluable testbed for the calibration of the local distance ladder. We present new, high-fidelity distance estimates to IC 1613 via its Tip of the Red Giant Branch (TRGB) and its RR Lyrae (RRL) variables…
The Fraction of Stars That Form in Clusters in Different Galaxies
Whitmore, Bradley C.; Fall, S. Michael; Chandar, Rupali +1 more
We estimate the fraction of stars that form in compact clusters (bound and unbound), {{{Γ }}}F, in a diverse sample of eight star-forming galaxies, including two irregulars, two dwarf starbursts, two spirals, and two mergers. The average value for our sample is {{{Γ }}}F≈ 24 % +/- 9 % . We also calculate the fraction of stars…
Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013EJ in Messier 74
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Wang, Lifan +6 more
SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears interme…