Search Publications
ALMA Observations of the Sub-kpc Structure of the Host Galaxy of a z = 6.5 Lensed Quasar: A Rotationally Supported Hyper-Starburst System at the Epoch of Reionization
Fan, Xiaohui; Keeton, Charles R.; Walter, Fabian +11 more
We report Atacama Large Millimeter/Submillimeter Array (ALMA) observations of the dust continuum and [C II] emission of the host galaxy of J0439+1634, a gravitationally lensed quasar at z = 6.5. Gravitational lensing boosts the source-plane resolution to ~0"15 (~0.8 kpc). The lensing model derived from the ALMA data is consistent with the fiducial…
TESS Asteroseismology of α Mensae: Benchmark Ages for a G7 Dwarf and Its M Dwarf Companion
Butler, R. Paul; Chaplin, William J.; Stassun, Keivan G. +27 more
Asteroseismology of bright stars has become increasingly important as a method to determine the fundamental properties (in particular ages) of stars. The Kepler Space Telescope initiated a revolution by detecting oscillations in more than 500 main-sequence and subgiant stars. However, most Kepler stars are faint and therefore have limited constrai…
Inspecting the Cepheid Distance Ladder: the Hubble Space Telescope Distance to the SN Ia Host Galaxy NGC 5584
Mérand, Antoine; Breuval, Louise; Gieren, Wolfgang +7 more
The current tension between the direct and the early-universe measurements of the Hubble constant, H0, requires detailed scrutiny of all the data and methods used in the studies on both sides of the debate. The Cepheids in the Type Ia supernova (SN Ia) host galaxy NGC 5584 played a key role in the local measurement of H0. The…
Further Evidence for Tidal Spin-up of Hot Jupiter Host Stars
Winn, Joshua N.; Anderson, Kassandra R.; Tejada Arevalo, Roberto A.
For most hot Jupiters around main-sequence Sun-like stars, tidal torques are expected to transfer angular momentum from the planet's orbit to the star's rotation. The timescale for this process is difficult to calculate, leading to uncertainties in the history of orbital evolution of hot Jupiters. We present evidence for tidal spin-up by taking ad…
An HST Survey of Protostellar Outflow Cavities: Does Feedback Clear Envelopes?
Manoj, P.; Kounkel, Marina; Pokhrel, Riwaj +10 more
We study protostellar envelope and outflow evolution using Hubble Space Telescope NICMOS or WFC3 images of 304 protostars in the Orion molecular clouds. These near-IR images resolve structures in the envelopes delineated by the scattered light of the central protostars with 80 au resolution, and they complement the 1.2 µm to 870 µm spe…
Energetic Electron Distribution of the Coronal Acceleration Region: First Results from Joint Microwave and Hard X-Ray Imaging Spectroscopy
Krucker, Säm; Reeves, Katharine K.; Chen, Bin +2 more
Nonthermal sources located above bright flare arcades, referred to as the "above-the-loop-top" sources, have been often suggested as the primary electron acceleration site in major solar flares. The X8.2 limb flare on 2017 September 10 features such an above-the-loop-top source, which was observed in both microwaves and hard X-rays (HXRs) by the E…
The MOSDEF Survey: Environmental Dependence of the Gas-phase Metallicity of Galaxies at 1.4 ≤ z ≤ 2.6
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +13 more
Using the near-IR spectroscopy of the MOSFIRE Deep Evolution Field survey, we investigate the role of the local environment in the gas-phase metallicity of galaxies. The local environment measurements are derived from accurate and uniformly calculated photometric redshifts with well-calibrated probability distributions. Based on rest-frame optical…
The Compact UV Size of Green Pea Galaxies As Local Analogs of High-redshift Lyα-Emitters
Kim, Keunho J.; Malhotra, Sangeeta; Yang, Huan +1 more
We study the dependence of Lyα escape from galaxies on UV continuum size and luminosity using a sample of 40 Green Pea (GP) galaxies, which are the best local analogs of high-redshift Lyα emitters (LAEs). We use the Cosmic Origins Spectrograph near-ultraviolet images from the Hubble Space Telescope to measure the UV size and luminosity with 0"047 …
The Luminosity Function of Bright QSOs at z ∼ 4 and Implications for the Cosmic Ionizing Background
Grazian, Andrea; Boutsia, Konstantina; Cupani, Guido +8 more
Based on results by recent surveys, the number of bright quasars at redshifts z > 3 is being constantly revised upward. The current consensus is that at bright magnitudes (M1450 ≤ -27) the number densities of such sources could have been underestimated by a factor of 30%-40%. In the framework of the QUBRICS survey, we identified 58 b…
ZTFJ0038+2030: A Long-period Eclipsing White Dwarf and a Substellar Companion
Kulkarni, S. R.; Bell, Keaton J.; Riddle, Reed +12 more
In a search for eclipsing white dwarfs using the Zwicky Transient Facility lightcurves, we identified a deep eclipsing white dwarf with an orbital period of 10.4 hr and an undetected substellar companion. We obtained high-speed photometry and radial velocity measurements to characterize the system. The white dwarf has a mass of 0.50 ± 0.02 M⊙…