Search Publications
A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). I. The Optical Counterparts of FIRST Radio Sources
Lee, Chien-Hsiu; Kajisawa, Masaru; Toba, Yoshiki +12 more
We report the result of optical identifications of FIRST radio sources with the Hyper Suprime-Cam Subaru Strategic Program survey (HSC-SSP). The positional cross-match within 1″ between the FIRST and HSC-SSP catalogs (i ≲ 26) produced more than 3600 optical counterparts in the 156 deg2 of the HSC-SSP field. The matched counterparts acco…
Observations of Electron-driven Evaporation in a Flare Precursor
Li, Dong; Ning, Zongjun; Li, Ying +2 more
We investigate the relationship between the blueshifts of a hot emission line and the nonthermal emissions in microwave and hard X-ray (HXR) wavelengths in the precursor of a solar flare on 2014 October 27. The flare precursor is identified as a small but well-developed peak in the soft X-ray and extreme-ultraviolet passbands before the GOES flare…
Collective Study of Polar Crown Filaments in the Past Four Solar Cycles
Xu, Yan; Jing, Ju; Wang, Haimin +3 more
Polar crown filaments (PCFs) form above the magnetic polarity inversion line, which separates the unipolar polar fields and the nearest dispersed fields from the trailing part of active regions with opposite polarity. The statistical properties of PCFs are correlated with the solar cycle. Therefore, the study of PCFs plays an important role in und…
Eta Carinae’s Declining Outflow Seen in the UV, 2002-2015
Humphreys, Roberta M.; Davidson, Kris; Martin, John C. +1 more
Existing Hubble Space Telescope UV data offer many previously neglected clues to η Car’s behavior since 2000. Here we examine a subset of observations with diverse results. (1) The star’s rapid change of state is confirmed by major changes in UV absorption lines, circumstellar extinction, and other features. (2) N III] λ1750 is one of the two most…
A Candidate Tidal Disruption Event in a Quasar at z = 2.359 from Abundance Ratio Variability
Shen, Yue; Jiang, Linhua; Liu, Xin +1 more
A small fraction of quasars show an unusually high nitrogen-to-carbon ratio (N/C) in their spectra. These “nitrogen-rich” (N-rich) quasars are a long-standing puzzle because their interstellar medium implies stellar populations with abnormally high metallicities. It has recently been proposed that N-rich quasars may result from tidal disruption ev…
The Origin of the 300 km s-1 Stream near Segue 1
Bovy, Jo; Beers, Timothy C.; Placco, Vinicius M. +13 more
We present a search for new members of the 300 km s-1 stream (300S) near the dwarf galaxy Segue 1 using wide-field survey data. We identify 11 previously unknown bright stream members in the APOGEE-2 and SEGUE-1 and 2 spectroscopic surveys. Based on the spatial distribution of the high-velocity stars, we confirm for the first time that …
A Study of Magnetic Field Characteristics of the Flaring Active Region Based on Nonlinear Force-free Field Extrapolation
Kusano, Kanya; Inoue, Satoshi; Bamba, Yumi +1 more
Coronal magnetic fields are responsible for the onset of solar flares and solar eruptions. However, the type of magnetic field parameters that can be used to measure the critical condition for a solar eruption is still unclear. As an effort to understand the possible condition for a solar flare, we have examined the nondimensional parameter κ intr…
Identification of the Infrared Counterpart of SGR 1935+2154 with the Hubble Space Telescope
Kouveliotou, Chryssa; Levan, Andrew; Fruchter, Andrew
We present deep Hubble Space Telescope observations of a new magnetar source, the soft gamma-repeater SGR 1935+2154, discovered by Swift. We obtained three epochs of observations: while the source was active in 2015 March, during a quiescent period in 2015 August, and during a further active phase in 2016 May. Close to the center of the X-ray erro…
The Orbit of the New Milky Way Globular Cluster FSR1716 = VVV-GC05
Hanke, Michael; Minniti, Dante; Gran, Felipe +10 more
We use deep, multi-epoch near-IR images of the VISTA Variables in the Vía Láctea (VVV) Survey to measure proper motions (PMs) of stars in the Milky Way globular cluster (GC) FSR1716 = VVV-GC05. The color-magnitude diagram of this object, made by using PM-selected members, shows an extended horizontal branch, nine confirmed RR Lyrae (RRL) members i…
Magnetic Loops above a Small Flux-emerging Region Observed by IRIS, Hinode, and SDO
Huang, Zhenghua
I report on observations of a set of magnetic loops above a region with late-phase flux emergence taken by IRIS, Hinode, and SDO. The loop system consists of many transition-region loop threads that are 5″-12″ in length and ∼0.″5 in width and coronal loops with similar length and ∼2″ width. Although the loop system consists of threads with differe…