Search Publications
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. II. The Most Luminous Standard Candles in the Universe
Kaspi, Shai; Netzer, Hagai; Du, Pu +8 more
This is the second in a series of papers reporting on a large reverberation mapping (RM) campaign to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). The goal is to identify super-Eddington accreting massive black holes (SEAMBHs) and to use their unique properties to construct a new method for measuring cosmologic…
What is the Physical Origin of Strong Lyα Emission? II. Gas Kinematics and Distribution of Lyα Emitters
Ono, Yoshiaki; Ouchi, Masami; Shibuya, Takatoshi +8 more
We present a statistical study of velocities of Lyα, interstellar (IS) absorption, and nebular lines and gas covering fraction for Lyα emitters (LAEs) at z ~= 2. We make a sample of 22 LAEs with a large Lyα equivalent width (EW) of >~ 50 Å based on our deep Keck/Low Resolution Imaging Spectrometer (LRIS) observations, in conjunction with spectr…
An Interface Region Imaging Spectrograph First View on Solar Spicules
Golub, L.; Tian, H.; De Pontieu, B. +17 more
Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere remains unknown. Here we give a first glimpse of what quiet-Sun spicules look like when observed with NASA's recently launched…
CANDELS/GOODS-S, CDFS, and ECDFS: Photometric Redshifts for Normal and X-Ray-Detected Galaxies
Barro, Guillermo; Ferguson, Henry C.; Grazian, Andrea +29 more
We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). This work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revis…
Extended Main Sequence Turnoffs in Intermediate-age Star Clusters: A Correlation between Turnoff Width and Early Escape Velocity
Girardi, Léo; Chandar, Rupali; Marigo, Paola +9 more
We present a color-magnitude diagram analysis of deep Hubble Space Telescope imaging of a mass-limited sample of 18 intermediate-age (1-2 Gyr old) star clusters in the Magellanic Clouds, including eight clusters for which new data were obtained. We find that all star clusters in our sample feature extended main-sequence turnoff (eMSTO) regions tha…
HST-COS Observations of AGNs. II. Extended Survey of Ultraviolet Composite Spectra from 159 Active Galactic Nuclei
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +1 more
The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting their emission-line spectra and for photoionizing and heating the intergalactic medium. Using far-ultraviolet (FUV) spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we directly measure the rest-frame ionizin…
Predicting the Sun's Polar Magnetic Fields with a Surface Flux Transport Model
Hathaway, David H.; Upton, Lisa
The Sun's polar magnetic fields are directly related to solar cycle variability. The strength of the polar fields at the start (minimum) of a cycle determine the subsequent amplitude of that cycle. In addition, the polar field reversals at cycle maximum alter the propagation of galactic cosmic rays throughout the heliosphere in fundamental ways. W…
Ultra-faint Ultraviolet Galaxies at z ~ 2 behind the Lensing Cluster A1689: The Luminosity Function, Dust Extinction, and Star Formation Rate Density
Teplitz, Harry I.; Richard, Johan; Scarlata, Claudia +8 more
We have obtained deep ultraviolet imaging of the lensing cluster A1689 with the WFC3/UVIS camera onboard the Hubble Space Telescope in the F275W (30 orbits) and F336W (4 orbits) filters. These images are used to identify z ~ 2 star-forming galaxies via their Lyman break, in the same manner that galaxies are typically selected at z >= 3. Because…
Evidence for Particle Re-acceleration in the Radio Relic in the Galaxy Cluster PLCKG287.0+32.9
Nonino, M.; van Weeren, R. J.; Röttgering, H. J. A. +5 more
Radio relics are diffuse radio sources observed in galaxy clusters, probably produced by shock acceleration during cluster-cluster mergers. Their large size, of the order of 1 Mpc, indicates that the emitting electrons need to be (re)accelerated locally. The usually invoked diffusive shock acceleration models have been challenged by recent observa…
Abundant Molecular Gas and Inefficient Star Formation in Intracluster Regions: Ram Pressure Stripped Tail of the Norma Galaxy ESO137-001
Combes, Françoise; Sun, Ming; Jáchym, Pavel +2 more
For the first time, we reveal large amounts of cold molecular gas in a ram-pressure-stripped tail, out to a large "intracluster" distance from the galaxy. With the Actama Pathfinder EXperiment (APEX) telescope, we have detected 12CO(2-1) emission corresponding to more than 109 M ⊙ of H2 in three Hα brigh…