Search Publications
Plasma and Magnetic Field Characteristics of Solar Coronal Mass Ejections in Relation to Geomagnetic Storm Intensity and Variability
Wang, Rui; Yang, Zhongwei; Liu, Ying D. +5 more
The largest geomagnetic storms of solar cycle 24 so far occurred on 2015 March 17 and June 22 with {D}{st} minima of -223 and -195 nT, respectively. Both of the geomagnetic storms show a multi-step development. We examine the plasma and magnetic field characteristics of the driving coronal mass ejections (CMEs) in connection with the de…
New Near-infrared Period-Luminosity-Metallicity Relations for RR Lyrae Stars and the Outlook for Gaia
Luri, X.; Clementini, G.; Ripepi, V. +6 more
We present results of the analysis of 70 RR Lyrae stars located in the bar of the Large Magellanic Cloud (LMC). Combining the spectroscopically determined metallicity of these stars from the literature with precise periods from the OGLE III catalog and multi-epoch Ks photometry from the VISTA survey of the Magellanic Clouds system, we d…
The Azimuthal Dependence of Outflows and Accretion Detected Using O VI Absorption
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +2 more
We report a bimodality in the azimuthal angle (Φ) distribution of gas around galaxies traced by O vi absorption. We present the mean Φ probability distribution function of 29 Hubble Space Telescope-imaged O vi absorbing (EW > 0.1 Å) and 24 non-absorbing (EW < 0.1 Å) isolated galaxies (0.08 \lt z \lt 0.67) within ∼200 kpc of background quasar…
Illuminating a Dark Lens : A Type Ia Supernova Magnified by the Frontier Fields Galaxy Cluster Abell 2744
Richard, Johan; Treu, Tommaso; Broadhurst, Tom +27 more
SN HFF14Tom is a Type Ia SN discovered at z=1.3457+/- 0.0001 behind the galaxy cluster Abell 2744 (z = 0.308). In a cosmology-independent analysis, we find that HFF14Tom is 0.77 ± 0.15 mag brighter than unlensed Type Ia SNe at similar redshift, implying a lensing magnification of {µ }{obs}=2.03+/- 0.29. This observed magnification…
Direct Imaging of an Asymmetric Debris Disk in the HD 106906 Planetary System
Murray-Clay, Ruth; Dong, Ruobing; Oppenheimer, Rebecca +53 more
We present the first scattered light detections of the HD 106906 debris disk using the Gemini/Gemini Planet Imager in the infrared and Hubble Space Telescope (HST)/Advanced Camera for Surveys in the optical. HD 106906 is a 13 Myr old F5V star in the Sco-Cen association, with a previously detected planet-mass candidate HD 106906b projected 650 AU f…
Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. III. Dynamical Distances and Mass-to-Light Ratios
Anderson, Jay; van der Marel, Roeland P.; Watkins, Laura L. +1 more
We present dynamical distance estimates for 15 Galactic globular clusters (GCs) and use these to check the consistency of dynamical and photometric distance estimates. For most of the clusters, this is the first dynamical distance estimate ever determined. We extract proper-motion (PM) dispersion profiles using cleaned samples of bright stars from…
Evolution in the Black Hole—Galaxy Scaling Relations and the Duty Cycle of Nuclear Activity in Star-forming Galaxies
Trump, Jonathan R.; Brandt, W. N.; Xue, Y. Q. +6 more
We measure the location and evolutionary vectors of 69 Herschel-detected broad-line active galactic nuclei (BLAGNs) in the {{M}BH}-{{M}*} plane. BLAGNs are selected from the COSMOS and CDF-S fields, and span the redshift range 0.2≤slant z\lt 2.1. Black hole masses are calculated using archival spectroscopy and single-epoch vi…
Luminous and Dark Matter Profiles from Galaxies to Clusters: Bridging the Gap with Group-scale Lenses
Treu, Tommaso; Ellis, Richard S.; Newman, Andrew B.
Observations of strong gravitational lensing, stellar kinematics, and larger-scale tracers enable accurate measures of the distribution of dark matter (DM) and baryons in massive early-type galaxies (ETGs). While such techniques have been applied to galaxy-scale and cluster-scale lenses, the paucity of intermediate-mass systems with high-quality d…
Revisiting Ulysses Observations of Interstellar Helium
Wood, Brian E.; Müller, Hans-Reinhard; Witte, Manfred
We report the results of a comprehensive reanalysis of Ulysses observations of interstellar He atoms flowing through the solar system, the goal being to reassess the interstellar He flow vector and to search for evidence of variability in this vector. We find no evidence that the He beam seen by Ulysses changes at all from 1994-2007. The direction…
Heating Signatures in the Disk Counterparts of Solar Spicules in Interface Region Imaging Spectrograph Observations
De Pontieu, B.; Rouppe van der Voort, L.; Carlsson, M. +2 more
We use coordinated observations with the Interface Region Imaging Spectrograph (IRIS) and the Swedish 1 m Solar Telescope to identify the disk counterpart of type II spicules in upper-chromospheric and transition region (TR) diagnostics. These disk counterparts were earlier identified through short-lived asymmetries in chromospheric spectral lines…