Search Publications
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…
The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source
Rest, A.; Foley, R. J.; Boutsia, K. +16 more
We present an analysis of the host-galaxy environment of Swope Supernova Survey 2017a (SSS17a), the discovery of an electromagnetic counterpart to a gravitational-wave source, GW170817. SSS17a occurred 1.9 kpc (in projection; 10.″2) from the nucleus of NGC 4993, an S0 galaxy at a distance of 40 Mpc. We present a Hubble Space Telescope (HST) pre-tr…
Deep CO(1-0) Observations of z = 1.62 Cluster Galaxies with Substantial Molecular Gas Reservoirs and Normal Star Formation Efficiencies
Papovich, Casey; Momcheva, Ivelina; Saintonge, Amelie +9 more
We present an extremely deep CO(1-0) observation of a confirmed z = 1.62 galaxy cluster. We detect two spectroscopically confirmed cluster members in CO(1-0) with signal-to-noise ratio > 5. Both galaxies have log({{ M }}\star /{{ M }}⊙ ) > 11 and are gas rich, with {{ M }}{mol}/({{ M }}\star +{{ M …
The Rest-frame Optical (900 nm) Galaxy Luminosity Function at z ∼ 4-7: Abundance Matching Points to Limited Evolution in the M STAR/M HALO Ratio at z ≥ 4
Muzzin, Adam; Labbé, Ivo; Bouwens, Rychard J. +4 more
We present the first determination of the galaxy luminosity function (LF) at z ∼ 4, 5, 6, and 7, in the rest-frame optical at {λ }{rest}∼ 900 {nm} (z‧ band). The rest-frame optical light traces the content in low-mass evolved stars (∼stellar mass—M *), minimizing potential measurement biases for M *. Moreover, it i…
No Overdensity of Lyman-Alpha Emitting Galaxies around a Quasar at z ∼ 5.7
Walter, F.; Decarli, R.; Overzier, R. +4 more
Bright quasars, observed when the universe was less than one billion years old (z > 5.5), are known to host massive black holes (∼109 M⊙) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations …