Search Publications
Possible Detection of the Stellar Donor or Remnant for the Type Iax Supernova 2008ha
Foley, Ryan J.; Rest, Armin; Fong, Wen-fai +5 more
Type Iax supernovae (SNe Iax) are thermonuclear explosions that are related to SNe Ia, but are physically distinct. The most important differences are that SNe Iax have significantly lower luminosity (1%-50% that of typical SNe Ia), lower ejecta mass (~0.1-0.5 M ⊙), and may leave a bound remnant. The most extreme SN Iax is SN 2008ha, wh…
The Megasecond Chandra X-Ray Visionary Project Observation of NGC 3115: Witnessing the Flow of Hot Gas within the Bondi Radius
Bregman, Joel N.; Wong, Ka-Wah; Irwin, Jimmy A. +3 more
Observational confirmation of hot accretion model predictions has been hindered by the challenge to resolve spatially the Bondi radii of black holes with X-ray telescopes. Here, we use the Megasecond Chandra X-ray Visionary Project observation of the NGC 3115 supermassive black hole to place the first direct observational constraints on the spatia…
Hubble Space Telescope and Ground-based Observations of the Type Iax Supernovae SN 2005hk and SN 2008A
Filippenko, Alexei V.; Schneider, Donald P.; Foley, Ryan J. +24 more
We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are…
Extended [C II] Emission in Local Luminous Infrared Galaxies
Elbaz, D.; Veilleux, S.; Sanders, D. B. +20 more
We present Herschel/PACS observations of extended [C II] 157.7 µm line emission detected on ~1-10 kpc scales in 60 local luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey. We find that most of the extra-nuclear emission show [C II]/FIR ratios >=4 × 10-3, larger than the mean ratio seen in the n…
Predicted Space Motions for Hypervelocity and Runaway Stars: Proper Motions and Radial Velocities for the Gaia Era
Geller, Margaret J.; Brown, Warren R.; Kenyon, Scott J. +1 more
We predict the distinctive three-dimensional space motions of hypervelocity stars (HVSs) and runaway stars moving in a realistic Galactic potential. For nearby stars with distances less than 10 kpc, unbound stars are rare; proper motions alone rarely isolate bound HVSs and runaways from indigenous halo stars. At large distances of 20-100 kpc, unbo…
Investigating Nearby Star-forming Galaxies in the Ultraviolet with HST/COS Spectroscopy. I. Spectral Analysis and Interstellar Abundance Determinations
Aloisi, A.; James, B. L.; Wolfe, M. A. +2 more
This is the first in a series of three papers describing a project with the Cosmic Origins Spectrograph on the Hubble Space Telescope to measure abundances of the neutral interstellar medium (ISM) in a sample of nine nearby star-forming galaxies. The goal is to assess the (in)homogeneities of the multiphase ISM in galaxies where the bulk of metals…
Effects of Meridional Flow Variations on Solar Cycles 23 and 24
Hathaway, David H.; Upton, Lisa
The faster meridional flow that preceded the solar cycle 23/24 minimum is thought to have led to weaker polar field strengths, producing the extended solar minimum and the unusually weak cycle 24. To determine the impact of meridional flow variations on the sunspot cycle, we have simulated the Sun's surface magnetic field evolution with our newly …
Absorption-line Detections of 105-106 K Gas in Spiral-rich Groups of Galaxies
Kacprzak, Glenn G.; Savage, Blair D.; Shull, J. Michael +10 more
Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 "warm" (T >= 105 K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a …
Star Formation Rates from [C II] 158 µm and Mid-infrared Emission Lines for Starbursts and Active Galactic Nuclei
Lebouteiller, V.; Sargsyan, L.; Samsonyan, A. +5 more
A summary is presented for 130 galaxies observed with the Herschel Photodetector Array Camera and Spectrometer instrument to measure fluxes for the [C II] 158 µm emission line. Sources cover a wide range of active galactic nucleus to starburst classifications, as derived from polycyclic aromatic hydrocarbon strength measured with the Spitzer…
A Solar Type II Radio Burst from Coronal Mass Ejection-Coronal Ray Interaction: Simultaneous Radio and Extreme Ultraviolet Imaging
Feng, Li; Li, Gang; Chen, Yao +5 more
Simultaneous radio and extreme ultraviolet (EUV)/white-light imaging data are examined for a solar type II radio burst occurring on 2010 March 18 to deduce its source location. Using a bow-shock model, we reconstruct the three-dimensional EUV wave front (presumably the type-II-emitting shock) based on the imaging data of the two Solar TErrestrial …