Search Publications
Temporal Evolution of Multiple Evaporating Ribbon Sources in a Solar Flare
Cauzzi, G.; Graham, D. R.
We present new results from the Interface Region Imaging Spectrograph (IRIS) showing the dynamic evolution of chromospheric evaporation and condensation in a flare ribbon, with the highest temporal and spatial resolution to date. IRIS observed the entire impulsive phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 s cadence “sit-and-stare”…
NuSTAR and Suzaku Observations of the Hard State in Cygnus X-1: Locating the Inner Accretion Disk
Harrison, F. A.; Stern, D.; Zhang, W. W. +20 more
We present simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR ) and Suzaku observations of the X-ray binary Cygnus X-1 in the hard state. This is the first time this state has been observed in Cyg X-1 with NuSTAR, which enables us to study the reflection and broadband spectra in unprecedented detail. We confirm that the iron line cannot be…
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II. Numerical Aspects
De Pontieu, B.; Yokoyama, T.; Okamoto, T. J. +3 more
Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun’s million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains elusive. Through advanced numerical simulations combined with appropriate forward modeling of a p…
Global Trends of CME Deflections Based on CME and Solar Parameters
Kay, C.; Opher, M.; Evans, R. M.
Accurate space weather forecasting requires knowledge of the trajectory of coronal mass ejections (CMEs), including any deflections close to the Sun or through interplanetary space. Kay et al. introduced ForeCAT, a model of CME deflection resulting from the background solar magnetic field. For a magnetic field solution corresponding to Carrington …
The Lyman Alpha Reference Sample. V. The Impact of Neutral ISM Kinematics and Geometry on Lyα Escape
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +15 more
We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyα Reference Sample; a sample of strongly star-forming galaxies at low redshifts (0.028 < z < 0.18). We compare the derived properties to global properties derived from multi-band imaging and 21 cm H i interferometry and single-dish observations, as well as archival op…
Detection of Broad Hα Emission Lines in the Late-time Spectra of a Hydrogen-poor Superluminous Supernova
Cenko, S. B.; Gal-Yam, A.; Kulkarni, S. R. +14 more
iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83-148 days to reach a peak bolometric luminosity of ∼1.3 × 1044 erg s-1, then decays slowly at 0.015 mag day-1. The measured ejecta velocity is ∼ 13,000…
Leo P: An Unquenched Very Low-mass Galaxy
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +8 more
Leo P is a low-luminosity dwarf galaxy discovered through the blind H i Arecibo Legacy Fast ALFA survey. The H i and follow-up optical observations have shown that Leo P is a gas-rich dwarf galaxy with active star formation, an underlying older population, and an extremely low oxygen abundance. We have obtained optical imaging with the Hubble Spac…
Stellar Populations from Spectroscopy of a Large Sample of Quiescent Galaxies at Z > 1: Measuring the Contribution of Progenitor Bias to Early Size Growth
Ellis, Richard S.; Belli, Sirio; Newman, Andrew B.
We analyze the stellar populations of a sample of 62 massive (log M */M ⊙ > 10.7) galaxies in the redshift range 1 < z < 1.6, with the main goal of investigating the role of recent quenching in the size growth of quiescent galaxies. We demonstrate that our sample is not biased toward bright, compact, or young galaxie…
The Rate of Core Collapse Supernovae to Redshift 2.5 from the CANDELS and CLASH Supernova Surveys
Ravindranath, Swara; Mobasher, Bahram; Riess, Adam G. +6 more
The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and Cluster Lensing And Supernova survey with Hubble multi-cycle treasury programs with the Hubble Space Telescope (HST) have provided new opportunities to probe the rate of core-collapse supernovae (CCSNe) at high redshift, now extending to z≈ 2.5. Here we use a sample of approxim…
A Very Deep Chandra Observation of the Galaxy Group NGC 5813: AGN Shocks, Feedback, and Outburst History
Simionescu, A.; Giacintucci, S.; David, L. +11 more
We present results from a very deep (650 ks) Chandra X-ray observation of the galaxy group NGC 5813, the deepest Chandra observation of a galaxy group to date. This system uniquely shows three pairs of collinear cavities, with each pair associated with an unambiguous active galactic nucleus (AGN) outburst shock front. The implied mean kinetic powe…