Search Publications
A Radio, Optical, UV, and X-Ray View of the Enigmatic Changing-look Active Galactic Nucleus 1ES 1927+654 from Its Pre- to Postflare States
Cenko, S. Bradley; Meyer, Eileen; Lusso, Elisabeta +17 more
The nearby Type II active galactic nucleus (AGN) 1ES 1927+654 went through a violent changing-look (CL) event beginning 2017 December during which the optical and UV fluxes increased by four magnitudes over a few months, and broad emission lines newly appeared in the optical/UV. By 2018 July, the X-ray coronal emission had completely vanished, onl…
The Rate, Amplitude, and Duration of Outbursts from Class 0 Protostars in Orion
Manoj, P.; Narang, Mayank; Pokhrel, Riwaj +18 more
At least half of a protostar's mass is accreted in the Class 0 phase, when the central protostar is deeply embedded in a dense, infalling envelope. We present the first systematic search for outbursts from Class 0 protostars in the Orion clouds. Using photometry from Spitzer/IRAC spanning 2004 to 2017, we detect three outbursts from Class 0 protos…
COCONUT, a Novel Fast-converging MHD Model for Solar Corona Simulations: I. Benchmarking and Optimization of Polytropic Solutions
Poedts, Stefaan; Zhang, Fan; Perri, Barbara +5 more
We present a novel global 3D coronal MHD model called COCONUT, polytropic in its first stage and based on a time-implicit backward Euler scheme. Our model boosts run-time performance in comparison with contemporary MHD-solvers based on explicit schemes, which is particularly important when later employed in an operational setting for space-weather…
Detection of a 100,000 M ⊙ black hole in M31's Most Massive Globular Cluster: A Tidally Stripped Nucleus
Pechetti, Renuka; Caldwell, Nelson; Kamann, Sebastian +6 more
We investigate the presence of a central black hole (BH) in B023-G078, M31's most massive globular cluster. We present high-resolution, adaptive-optics assisted, integral-field spectroscopic kinematics from Gemini/NIFS that show a strong rotation (~20 km s-1) and a velocity dispersion rise toward the center (37 km s-1). We co…
Blue Rest-frame UV-optical Colors in z 8 Galaxies from GREATS: Very Young Stellar Populations at 650 Myr of Cosmic Time
Illingworth, Garth D.; Labbé, Ivo; van Dokkum, Pieter +4 more
Deep rest-optical observations are required to accurately constrain the stellar populations of z ~ 8 galaxies. Due to significant limitations in the availability of such data for statistically complete samples, observational results have been limited to modest numbers of bright or lensed sources. To revolutionize the present characterization of z …
Quasi-periodic Energy Release and Jets at the Base of Solar Coronal Plumes
Kumar, Pankaj; Deforest, Craig E.; Karpen, Judith T. +3 more
Coronal plumes are long, ray-like, open structures that have been considered as possible sources of the solar wind. Their origin in the largely unipolar coronal holes has long been a mystery. Earlier spectroscopic and imaging observations revealed blueshifted plasma and propagating disturbances (PDs) in plumes that are widely interpreted in terms …
The Rapid X-Ray and UV Evolution of ASASSN-14ko
Lin, Chien-Cheng; Holoien, Thomas W. -S.; Auchettl, Katie +13 more
ASASSN-14ko is a recently discovered periodically flaring transient at the center of the active galactic nucleus (AGN) ESO 253-G003 with a slowly decreasing period. Here, we show that the flares originate from the northern, brighter nucleus in this dual-AGN, post-merger system. The light curves for the two flares that occurred in 2020 May and Sept…
METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. III. Interstellar Depletions, Dust-to-Metal, and Dust-to-Gas Ratios versus Metallicity
Jenkins, Edward B.; Yanchulova Merica-Jones, Petia; Gordon, Karl D. +9 more
The metallicity and gas density dependence of interstellar depletions, the dust-to-gas (D/G), and dust-to-metal (D/M) ratios have important implications for how accurately we can trace the chemical enrichment of the universe, either by using FIR dust emission as a tracer of the ISM or by using spectroscopy of damped Lyα systems to measure chemical…
Clearing the Hurdle: The Mass of Globular Cluster Systems as a Function of Host Galaxy Mass
Harris, William E.; Eadie, Gwendolyn M.; Springford, Aaron
Current observational evidence suggests that all large galaxies contain globular clusters (GCs), while the smallest galaxies do not. Over what galaxy mass range does the transition from GCs to no GCs occur? We investigate this question using galaxies in the Local Group (LG), nearby dwarf galaxies, and galaxies in the Virgo Cluster Survey. We consi…
The CGM2 Survey: Circumgalactic O VI from Dwarf to Massive Star-forming Galaxies
Tripp, Todd M.; Prochaska, J. Xavier; Tejos, Nicolas +9 more
We combine 126 new galaxy-O VI absorber pairs from the CGM2 survey with 123 pairs drawn from the literature to examine the simultaneous dependence of the column density of O VI absorbers (N O VI) on galaxy stellar mass, star-formation rate, and impact parameter. The combined sample consists of 249 galaxy-O VI absorber pairs …