Search Publications
Simultaneous X-Ray and Infrared Observations of Sagittarius A*'s Variability
Ponti, G.; Fazio, G. G.; Morris, M. R. +11 more
Emission from Sagitarius A* is highly variable at both X-ray and infrared (IR) wavelengths. Observations over the last ∼20 yr have revealed X-ray flares that rise above a quiescent thermal background about once per day, while faint X-ray flares from Sgr A* are undetectable below the constant thermal emission. In contrast, the IR emission of Sgr A*…
A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data
Lee, Chien-Hsiu; Schramm, Malte; Ueda, Yoshihiro +14 more
We present physical properties of radio galaxies (RGs) with f 1.4 GHz > 1 mJy discovered by Subaru Hyper Suprime-Cam (HSC) and Very Large Array Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0 < z ≤ 1.7 with HSC counterparts in about 100 deg2, we compiled multi-wavelength data …
Analysis of Small-scale Magnetic Flux Ropes Covering the Whole Ulysses Mission
Hu, Qiang; Chen, Yu; le Roux, Jakobus A.
Small-scale magnetic flux ropes in the solar wind have been studied for decades via both simulation and observation. Statistical analysis utilizing various in situ spacecraft measurements is the main observational approach, which helps investigate the generation and evolution of these small-scale structures. In this study, we extend the automated …
The redshift evolution of X-ray and Sunyaev-Zel'dovich scaling relations in the FABLE simulations
Sijacki, Debora; Puchwein, Ewald; Henden, Nicholas A.
We study the redshift evolution of the X-ray and Sunyaev-Zel'dovich (SZ) scaling relations for galaxy groups and clusters in the FABLE suite of cosmological hydrodynamical simulations. Using an expanded sample of 27 high-resolution zoom-in simulations, together with a uniformly sampled cosmological volume to sample low-mass systems, we find very g…
CME Arrival Time Prediction Using Convolutional Neural Network
Liu, Jiajia; Erdélyi, Robert; Wang, Yimin +1 more
Fast and accurate prediction of the arrival time of coronal mass ejections (CMEs) at Earth is vital to minimize hazards caused by CMEs. In this paper, we use a deep-learning framework, i.e., a convolutional neural network (CNN) regression model, to analyze transit times from the Sun to Earth of 223 geoeffective CME events observed in the past 30 y…
Discovery of a Disrupting Open Cluster Far into the Milky Way Halo: A Recent Star Formation Event in the Leading Arm of the Magellanic Stream?
Choi, Yumi; Nidever, David L.; Price-Whelan, Adrian M. +4 more
We report the discovery of a young (τ ∼ 117 {{Myr}}), low-mass (M∼ 1200 {M}⊙ ), metal-poor ([{{Fe}}/{{H}}]∼ -1.14) stellar association at a heliocentric distance D≈ 28.7 {{kpc}}, placing it far into the Milky Way (MW) halo. At its present Galactocentric position (R,z)∼ (23,15) {{kpc}}, the association is (on the sky) near the leading ar…
Photoionized emission and absorption features in the high-resolution X-ray spectra of NGC 3783
Kaastra, J. S.; Kriss, G. A.; Arav, N. +14 more
Our Swift monitoring program triggered two joint XMM-Newton, NuSTAR, and HST observations on 11 and 21 December 2016 targeting NGC 3783 because its soft X-ray continuum was heavily obscured. Consequently, emission features, including the O VII radiative recombination continuum, stand out above the diminished continuum. We focus on the photoionized…
Direct T e Metallicity Calibration of R23 in Strong Line Emitters
Malhotra, Sangeeta; Yang, Huan; Rhoads, James E. +1 more
The gas metallicity of galaxies is often estimated using strong emission lines such as the optical lines of [O III] and [O II]. The most common measure is “R23,” defined as ([O II]λλ3726, 3729 + [O III]λλ4959,5007)/Hβ. Most calibrations for these strong-line metallicity indicators are for continuum selected galaxies. We report a new empirical cali…
The Third Data Release of the Beijing-Arizona Sky Survey
Myers, Adam D.; Fan, Xiaohui; Jiang, Linhua +45 more
The Beijing-Arizona Sky Survey (BASS) is a wide and deep imaging survey that covers a 5400 deg2 area in the northern Galactic cap with the 2.3 m Bok telescope using two filters (g and r bands). The Mosaic z-band Legacy Survey (MzLS) covers the same area in the z band with the 4 m Mayall telescope. These two surveys will be used for spec…
A 3 Gyr White Dwarf with Warm Dust Discovered via the Backyard Worlds: Planet 9 Citizen Science Project
Debes, John H.; Wisniewski, John; Meisner, Aaron M. +13 more
Infrared excesses due to dusty disks have been observed orbiting white dwarfs with effective temperatures between 7200 and 25,000 K, suggesting that the rate of tidal disruption of minor bodies massive enough to create a coherent disk declines sharply beyond 1 Gyr after white dwarf formation. We report the discovery that the candidate white dwarf …