Search Publications
The Distribution of Satellites around Massive Galaxies at 1 < z < 3 in ZFOURGE/CANDELS: Dependence on Star Formation Activity
Papovich, Casey; Ferguson, Henry C.; Koekemoer, Anton M. +23 more
We study the statistical distribution of satellites around star-forming and quiescent central galaxies at 1 < z < 3 using imaging from the FourStar Galaxy Evolution Survey and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey. The deep near-IR data select satellites down to log (M/M ⊙) > 9 at z < 3. The radial sat…
A New Detection of LYα Absorption from the Heliotail
Redfield, Seth; Wood, Brian E.; Edelman, Eric +2 more
We present new Hubble Space Telescope observations of H I Lyα absorption toward the F8 V star HD 35296. This line of sight is only a few degrees from the downwind direction of the local interstellar medium flow vector. As a consequence, Lyα absorption from the heliotail is detected in the spectrum, consistent with three previous downwind detection…
Search for the Infrared Emission Features from Deuterated Interstellar Polycyclic Aromatic Hydrocarbons
Onaka, Takashi; Sakon, Itsuki; Kaneda, Hidehiro +4 more
We report the results of a search for emission features from interstellar deuterated polycyclic aromatic hydrocarbons (PAHs) in the 4 µm region with the Infrared Camera (IRC) on board AKARI. No significant excess emission is seen in 4.3-4.7 µm in the spectra toward the Orion Bar and M17 after the subtraction of line emission from the i…
Charge State Evolution in the Solar Wind. III. Model Comparison with Observations
Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A. +3 more
We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to p…
Constraining the Age of the NGC 4565 H I Disk Warp: Determining the Origin of Gas Warps
Bell, Eric F.; Holwerda, Benne W.; Monachesi, Antonela +7 more
We have mapped the distribution of young and old stars in the gaseous H I warp of NGC 4565. We find a clear correlation of young stars (<600 Myr) with the warp but no coincident old stars (>1 Gyr), which places an upper limit on the age of the structure. The formation rate of the young stars, which increased ~300 Myr ago relative to the surr…
Discovery of a Gas-rich Companion to the Extremely Metal-poor Galaxy DDO 68
Bailin, Jeremy; McQuinn, Kristen B. W.; Cannon, John M. +17 more
We present H I spectral-line imaging of the extremely metal-poor galaxy DDO 68. This system has a nebular oxygen abundance of only ~3% Z ⊙, making it one of the most metal-deficient galaxies known in the local volume. Surprisingly, DDO 68 is a relatively massive and luminous galaxy for its metal content, making it a significant outlier …
Microlensing Events by Proxima Centauri in 2014 and 2016: Opportunities for Mass Determination and Possible Planet Detection
Anderson, Jay; Bond, Howard E.; Sahu, Kailash C. +1 more
We have found that Proxima Centauri, the star closest to our Sun, will pass close to a pair of faint background stars in the next few years. Using Hubble Space Telescope (HST) images obtained in 2012 October, we determine that the passage close to a mag 20 star will occur in 2014 October (impact parameter 1.''6), and to a mag 19.5 star in 2016 Feb…
Tracing Ram-pressure Stripping with Warm Molecular Hydrogen Emission
Rieke, George H.; Rieke, Marcia J.; Sivanandam, Suresh
We use the Spitzer Infrared Spectrograph to study four infalling cluster galaxies with signatures of ongoing ram-pressure stripping. H2 emission is detected in all four, and two show extraplanar H2 emission. The emission usually has a warm (T ~ 115-160 K) and a hot (T ~ 400-600 K) component that is approximately two orders of…
Navy Precision Optical Interferometer Measurements of 10 Stellar Oscillators
van Belle, Gerard T.; Zavala, R. T.; Schmitt, Henrique R. +3 more
Using the Navy Precision Optical Interferometer, we measured the angular diameters of 10 stars that have previously measured solar-like oscillations. Our sample covered a range of evolutionary stages but focused on evolved subgiant and giant stars. We combined our angular diameters with Hipparcos parallaxes to determine the stars' physical radii, …
The Chemical Evolution of Phosphorus
Matteucci, Francesca; Roederer, Ian U.; Frebel, Anna +3 more
Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 Å) that is measurable in stars of low metallicity. Using…