Search Publications
Characteristics of Late-phase >100 MeV Gamma-Ray Emission in Solar Eruptive Events
White, S. M.; Dennis, B. R.; Murphy, R. J. +5 more
We characterize and catalog 30 solar eruptive events observed by the Fermi Large Area Telescope (LAT) having late-phase >100 MeV γ-ray emission (LPGRE), identified 30 yr ago in what were called long-duration gamma-ray flares. We show that LPGRE is temporally and spectrally distinct from impulsive phase emission in these events. The spectra are …
BANYAN. XII. New Members of Nearby Young Associations from GAIA-Tycho Data
Faherty, Jacqueline K.; Gagné, Jonathan; Doyon, René +2 more
We present a search for stellar members of young associations within 150 pc of the Sun, based on TGAS and an updated version of the BANYAN Σ software to determine Bayesian membership probabilities that includes Gaia-2MASS color-magnitude diagrams. We identify 32 new F0-M3-type bona fide members of the 10-200 Myr old Sco-Cen, Carina, Tucana-Horolog…
The Redshift Evolution of Rest-UV Spectroscopic Properties in Lyman-break Galaxies at z ∼ 2-4
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +8 more
We present the first comprehensive evolutionary analysis of the rest-frame UV spectroscopic properties of star-forming galaxies at z ∼ 2-4. We match samples at different redshifts in UV luminosity and stellar mass, and perform systematic measurements of spectral features and stellar population modeling. By creating composite spectra grouped accord…
The Distance of the Dark Matter Deficient Galaxy NGC 1052-DF2
van Dokkum, Pieter; Romanowsky, Aaron J.; Conroy, Charlie +2 more
We recently inferred that the galaxy NGC 1052-DF2 has little or no dark matter and a rich system of unusual globular clusters. We assumed that the galaxy is a satellite of the luminous elliptical galaxy NGC 1052 at ≈20 Mpc, on the basis of its surface brightness fluctuations (SBFs) distance of 19.0 ± 1.7 Mpc, its radial velocity of ≈1800 km s…
Detecting Black Hole Binaries by Gaia
Bulik, Tomasz; Piran, Tsvi; Kawanaka, Norita +1 more
We study the prospects of the Gaia satellite to identify black hole (BH) binary systems by detecting the orbital motion of the companion stars. Taking into account the initial mass function, mass transfer, common envelope phase, interstellar absorption, and identifiability of the systems, we estimate the number of BH binaries that can be detected …
Application of the Deep Convolutional Neural Network to the Forecast of Solar Flare Occurrence Using Full-disk Solar Magnetograms
Moon, Yong-Jae; Lim, Daye; Lee, Harim +4 more
In this study, we present the application of the Convolutional Neural Network (CNN) to the forecast of solar flare occurrence. For this, we consider three CNN models (two pretrained models, AlexNet and GoogLeNet, and one newly proposed model). Our inputs are SOHO/Michelson Doppler Imager (from 1996 May to 2010 December) and SDO/Helioseismic and Ma…
ALMA Observations of Molecular Clouds in Three Group-centered Elliptical Galaxies: NGC 5846, NGC 4636, and NGC 5044
Brighenti, Fabrizio; Mathews, William G.; Temi, Pasquale +4 more
We present new ALMA CO(2-1) observations of two well-studied group-centered elliptical galaxies: NGC 4636 and NGC 5846. In addition, we include a revised analysis of Cycle 0 ALMA observations of the central galaxy in the NGC 5044 group. We find evidence that molecular gas is a common presence in bright group-centered galaxies (BGG). CO line widths…
A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). III. A Large Sample of ALMA Sources in the GOODS-S
Bauer, F. E.; Wang, W. -H.; Barger, A. J. +3 more
We analyze the >4σ sources in the most sensitive 100 arcmin2 area (rms < 0.56 mJy) of a SCUBA-2 850 µm survey of the GOODS-S and present the 75 band-7 ALMA sources (>4.5σ) obtained from high-resolution interferometric follow-up observations. The raw SCUBA-2 >4σ limit is fainter than 2.25 mJy throughout this region, and…
Investigating the Response of Loop Plasma to Nanoflare Heating Using RADYN Simulations
Reale, Fabio; De Pontieu, B.; Carlsson, M. +5 more
We present the results of 1D hydrodynamic simulations of coronal loops that are subject to nanoflares, caused by either in situ thermal heating or nonthermal electron (NTE) beams. The synthesized intensity and Doppler shifts can be directly compared with Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) observatio…
Gaia and the Galactic Center Origin of Hypervelocity Stars
Geller, Margaret J.; Brown, Warren R.; Kenyon, Scott J. +1 more
We use new Gaia measurements to explore the origin of the highest velocity stars in the hypervelocity star (HVS) survey. The measurements reveal a clear pattern in B-type stars. Halo stars dominate the sample at speeds of ≃100 km s-1 below Galactic escape velocity. Disk runaway stars have speeds up to ≃100 km s-1 above Galact…