Search Publications
Galaxy Merger Fractions in Two Clusters at z\sim 2 Using the Hubble Space Telescope
Papovich, Casey; van Dokkum, Pieter; Momcheva, Ivelina +9 more
We measure the fraction of galaxy-galaxy mergers in two clusters at z ∼ 2 using imaging and grism observations from the Hubble Space Telescope. The two galaxy cluster candidates were originally identified as overdensities of objects using deep mid-infrared imaging and observations from the Spitzer Space Telescope, and were subsequently followed up…
An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS). V. The Period-Luminosity Relation for Dusty Metal-poor AGB Stars
van Loon, J. Th.; Gehrz, R. D.; Skillman, E. D. +10 more
The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS) has identified hundreds of candidate dust-producing asymptotic giant branch (AGB) stars in several nearby metal-poor galaxies. We have obtained multi-epoch follow-up observations for these candidates with the Spitzer Space Telescope and measured their infrared (IR) light curves. This h…
Testing Feedback-regulated Star Formation in Gas-rich, Turbulent Disk Galaxies
Bolatto, A. D.; Fisher, D. B.; Glazebrook, K. +3 more
In this paper we compare the molecular gas depletion times and midplane hydrostatic pressure in turbulent, star-forming disk galaxies to internal properties of these galaxies. For this analysis we use 17 galaxies from the DYNAMO sample of nearby (z ∼ 0.1) turbulent disks. We find a strong correlation, such that galaxies with lower molecular gas de…
H 0 Tension and the Phantom Regime: A Case Study in Terms of an Infrared f(T) Gravity
El-Zant, Amr; El Hanafy, Waleed; Elgammal, Sherif
We propose an f(T) teleparallel gravity theory including a torsional infrared (IR) correction. We show that the governing Friedmann’s equations of a spatially flat universe include a phantom-like effective dark energy term sourced by the torsion IR correction. As has been suggested, this phantom phase does indeed act to reconcile the tension betwe…
Constraining the Magnetic Field in the TeV Halo of Geminga with X-Ray Observations
Liu, Ruo-Yu; Ge, Chong; Wang, Xiang-Yu +1 more
Recently, the High Altitude Water Cherenkov (HAWC) collaboration reported the discovery of a TeV halo around the Geminga pulsar. The TeV emission is believed to originate from the inverse Compton scattering of pulsar-injected electrons/positrons off cosmic microwave background photons. During this time, these electrons should inevitably radiate X-…
Chemical and Kinematic Properties of the Galactic Disk from the LAMOST and Gaia Sample Stars
Shi, Jianrong; Chen, Yuqin; Ma, Jun +5 more
We determined the chemical and kinematic properties of the Galactic thin and thick disk using a sample of 307,246 A/F/G/K-type giant stars from the LAMOST spectroscopic survey and Gaia DR2 survey. Our study found that the thick disk globally exhibits no metallicity radial gradient, but the inner disk (R ≤ 8 kpc) and the outer disk (R > 8 kpc) h…
Testing the Evolutionary Link between Type 1 and Type 2 Quasars with Measurements of the Interstellar Medium
Ho, Luis C.; Shangguan, Jinyi
In a popular scenario for the coevolution of massive black holes and galaxies, major mergers of gas-rich galaxies fuel vigorous star formation and obscured (type 2) quasar activity until energy feedback from the active galactic nucleus (AGN) clears away the gas and dust to reveal an unobscured (type 1) quasar. Under this scenario, the precursor ty…
Multi-epoch Direct Imaging and Time-variable Scattered Light Morphology of the HD 163296 Protoplanetary Disk
Henning, Thomas; Nakagawa, Takao; Terada, Hiroshi +58 more
We present H-band polarized scattered light imagery and JHK high-contrast spectroscopy of the protoplanetary disk around HD 163296 observed with the High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) and Subaru Coronagraphic Extreme Adaptive Optics (SCExAO)/Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) instrument…
X-Ray Observations of a z ∼ 6.2 Quasar/Galaxy Merger
Fan, Xiaohui; Mulchaey, John S.; Walter, Fabian +7 more
Quasars at early redshifts (z > 6) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. Here, we report on a 150 ks Chandra observation of PSO J308.0416-21.2339, a z = 6.23 quasar with a merging companion galaxy identified in [C II] and rest-frame UV emission. With {72.3}-8.6
Exomoons in the Habitable Zones of M Dwarfs
Piro, Anthony L.; Barnes, Rory; Martínez-Rodríguez, Héctor +2 more
M dwarfs host most of the exoplanets in the local Milky Way. Some of these planets, ranging from sub-Earths to super-Jupiters, orbit in their stars’ habitable zones (HZs), although many likely possess surface environments that preclude habitability. Moreover, exomoons around these planets could harbor life for long timescales and thus may also be …