Search Publications
Ubiquitous [O II] Emission in Quiescent Galaxies at z ≈ 0.85 from the LEGA-C Survey
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +12 more
Using deep rest-frame optical spectroscopy from the Large Early Galaxy Astrophysical Census (LEGA-C) survey, conducted using VIMOS on the ESO Very Large Telescope, we search for low-ionization [O II] λ λ 3726,3729 emission in the spectra of a mass-complete sample of z ≈ 0.85 galaxies. We find that 59% of UVJ-quiescent (i.e., non-star-forming) gala…
Stellar Dynamical Models for 797 z 0.8 Galaxies from LEGA-C
Bell, Eric F.; Maseda, Michael V.; Franx, Marijn +12 more
We present spatially resolved stellar kinematics for 797 z = 0.6-1 galaxies selected from the LEGA-C survey and construct axisymmetric Jeans models to quantify their dynamical mass and degree of rotational support. The survey is K s -band selected, irrespective of color or morphological type, and allows for a first assessment of the st…
Extreme r-process Enhanced Stars at High Metallicity in Fornax
Hansen, C. J.; Reichert, M.; Arcones, A.
We present and discuss three extremely r-process enhanced stars located in the massive dwarf spheroidal galaxy Fornax. These stars are very unique with an extreme Eu enrichment (1.25 ≤ [Eu/Fe]≤1.45) at high metallicities (-1.3 ≤ [Fe/H]≤-0.8). They have the largest Eu abundances ever observed in a dwarf galaxy opening new opportunities to further u…
AGN Triality of Triple Mergers: Detection of Faint X-Ray Point Sources
Gültekin, Kayhan; Runnoe, Jessie C.; Foord, Adi +1 more
We present results from our X-ray analysis of a systematic search for triple active galactic nuclei (AGNs) in nearby (z < 0.077) triple galaxy mergers. We analyze archival Chandra observations of seven triple galaxy mergers with BAYMAX (Bayesian Analysis of Multiple AGNs in X-rays), fitting each observation with single, dual, and triple X-ray p…
What Makes Quadruply Lensed Quasars Quadruple?
Schechter, Paul L.; Luhtaru, Richard; de Soto, Kaylee M.
Among known strongly lensed quasar systems, ~25% have gravitational potentials sufficiently flat (and sources sufficiently well aligned) to produce four images rather than two. The projected flattening of the lensing galaxy and tides from neighboring galaxies both contribute to the potential's quadrupole. Witt's hyperbola and Wynne's ellipse permi…
A Case against a Significant Detection of Precession in the Galactic Warp
López-Corredoira, M.; Chrobáková, Ž.
Recent studies of warp kinematics using Gaia DR2 data have produced detections of warp precession for the first time, which greatly exceeds theoretical predictions of models. However, this detection assumes a warp model derived for a young population (few tens of megayears) to fit velocities of an average older stellar population of the thin disk …
Strong Mg II and Fe II Absorbers at 2.2 < z < 6.0
Willott, Chris J.; Shen, Yue; Ho, Luis C. +13 more
We present a study of strong intervening absorption systems in the near-IR spectra of 31 luminous quasars at z > 5.7. The quasar spectra were obtained with Gemini GNIRS that provide continuous wavelength coverage from ∼0.9 to ∼2.5 µm. We detect 32 strong Mg II doublet absorbers with rest-frame equivalent width Wr(λ2796) > 1.…
Dynamical Masses and Stellar Evolutionary Model Predictions of M Stars
Herczeg, Gregory J.; Wilner, David J.; Andrews, Sean M. +9 more
In this era of Gaia and ALMA, dynamical stellar mass measurements, derived from spatially and spectrally resolved observations of the Keplerian rotation of circumstellar disks, provide benchmarks that are independent of observations of stellar characteristics and their uncertainties. These benchmarks can then be used to validate and improve stella…
Semiempirical Modeling of the Atmospheres of the M Dwarf Exoplanet Hosts GJ 832 and GJ 581
France, Kevin; Linsky, Jeffrey L.; Buccino, Andrea P. +2 more
Stellar ultraviolet (UV) radiation drives photochemistry, and extreme-ultraviolet (EUV) radiation drives mass loss in exoplanet atmospheres. However, the UV flux is partly unobservable due to interstellar absorption, particularly in the EUV range (100-912 Å). It is therefore necessary to reconstruct the unobservable spectra in order to characteriz…
The Atacama Cosmology Telescope: A Search for Planet 9
Hasselfield, Matthew; Sifón, Cristóbal; Aiola, Simone +37 more
We use Atacama Cosmology Telescope (ACT) observations at 98 GHz (2015-2019), 150 GHz (2013-2019), and 229 GHz (2017-2019) to perform a blind shift-and-stack search for Planet 9. The search explores distances from 300 au to 2000 au and velocities up to 6.'3 per year, depending on the distance (r). For a 5 Earth-mass Planet 9 the detection limit var…