Search Publications
Investigating the Origin of the Absorption-line Variability in the Narrow-line Seyfert 1 Galaxy WPVS 007
Komossa, S.; Gallagher, Sarah C.; Terndrup, Donald M. +5 more
Broad absorption line quasars are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depending on the source. WPVS 007, a low-redshift, low-luminosity narrow-line Seyfert 1 (NLS1) shows strong varia…
Anisotropic Ionizing Illumination from an M-type Pre-main-sequence Star, DM Tau
Tamura, Motohide; Liu, Hauyu Baobab; Hashimoto, Jun +6 more
The powerful, high-energy magnetic activities of young stars play important roles in the magnetohydrodynamics in the innermost parts of the protoplanetary disks. In addition, the associated UV and X-ray emission dictates the photochemistry; moreover, the corona activities can affect the atmosphere of a newborn extrasolar planet. How the UV and X-r…
Expulsion of Counter Evershed Flows from Sunspot Penumbrae
Solanki, S. K.; Korpi-Lagg, A.; Castellanos Durán, J. S.
In addition to the Evershed flow directed from the umbra toward the outer boundary of a sunspot, under special circumstances a counter Evershed flow (CEF) in the opposite direction also occurs. We aim to characterize the proper motions and evolution of three CEFs observed by the Solar Optical Telescope on board the Japanese Hinode spacecraft and t…
When the Stars Align: A 5σ Concordance of Planetary Nebulae Major Axes in the Center of Our Galaxy
Parker, Quentin A.; Ritter, Andreas; Zijlstra, Albert A. +2 more
We report observations of a remarkable major axes alignment nearly parallel to the Galactic plane of 5σ significance for a subset of bulge "planetary nebulae" (PNe) that host, or are inferred to host, short-period binaries. Nearly all are bipolar. It is solely this specific PN population that accounts for the much weaker statistical alignments pre…
An Ongoing Tidal Capture in the Large Magellanic Cloud: The Low-mass Star Cluster KMK 88-10 Captured by the Massive Globular Cluster NGC 1835?
Vesperini, Enrico; Cadelano, Mario; Pallanca, Cristina +6 more
In the context of a project aimed at characterizing the dynamical evolution of old globular clusters in the Large Magellanic Cloud, we have secured deep HST/WFC3 images of the massive cluster NGC 1835. In the field of view of the acquired images, at a projected angular separation of approximately 2' from the cluster, we detected the small stellar …
Three-stage Collapse of the Long Gamma-Ray Burst from GRB 160625B Prompt Multiwavelength Observations
Rebolo, R.; Lipunov, V. M.; Kornilov, V. G. +37 more
This article presents the early results of synchronous multiwavelength observations of one of the brightest gamma-ray bursts (GRBs) GRB 160625B with the detailed continuous fast optical photometry of its optical counterpart obtained by MASTER and with hard X-ray and gamma-ray emission, obtained by the Lomonosov and Konus-Wind spacecraft. The detai…
Optical and Near-infrared Continuum Emission Region Size Measurements in the Lensed Quasar FBQ J0951+2635
Vrba, Frederick J.; Dahm, Scott E.; Morgan, Christopher W. +5 more
We present 10 seasons of Sloan Digital Sky Survey r-band monitoring observations and five seasons of H-band observations of the two-image system FBQ J0951+2635 from the Kaj Strand Astrometric Reflector at the United States Naval Observatory, Flagstaff Station. We supplement our light curves with six seasons of monitoring data from the literature t…
Carbon Abundance of Globular Cluster M22 (NGC 6656) and the Surface Carbon Depletion Rates of the Milky Way Globular Clusters
Lee, Jae-Woo
It is well known that metal-poor red giant branch (RGB) stars show variations in some elemental abundances, including carbon, due to the internal mixing accompanied by their own in situ CN cycle in the hydrogen burning shell. With our new photometric carbon abundance measurements of RGB stars in M22 and other globular clusters (GCs) in our previou…
High-resolution Observations of Plume Footpoints in a Solar Coronal Hole
Cao, Wenda; Yurchyshyn, Vasyl; Madjarska, Maria S. +7 more
Plumes are bright structures in coronal holes extending from the solar surface into the corona and are considered as a possible source of the solar wind. Plumes are thought to be rooted in strong unipolar photospheric flux patches (network/plage region). The magnetic activities at the base of plumes may play a crucial role in producing outflows an…
White Dwarf Photospheric Abundances in Cataclysmic Variables. III. Five Dwarf Novae with an Evolved Secondary Donor Star
Sion, Edward M.; Godon, Patrick
In the last two decades infrared spectroscopy has brought mounting evidence, in the form of weak CO features together with enhanced 13C, of the presence of CNO-processed material in the atmosphere of the donor star of some nonmagnetic cataclysmic variables. Some of these donors also exhibit a temperature too high for their binary orbita…