Search Publications
Further Evidence of Modified Spin-down in Sun-like Stars: Pileups in the Temperature-Period Distribution
Angus, Ruth; van Saders, Jennifer L.; Zinn, Joel C. +5 more
We combine stellar surface rotation periods determined from NASA's Kepler mission with spectroscopic temperatures to demonstrate the existence of pileups at the long-period and short-period edges of the temperature-period distribution for main-sequence stars with temperatures exceeding ~5500 K. The long-period pileup is well described by a curve o…
No Redshift Evolution of Galaxies' Dust Temperatures Seen from 0 < z < 2
Casey, Caitlin M.; Drew, Patrick M.
Some recent literature has claimed there to be an evolution in galaxies' dust temperatures toward warmer (or colder) spectral energy distributions (SEDs) between low and high redshift. These conclusions are driven by both theoretical models and empirical measurement. Such claims sometimes contradict one another and are prone to biases in samples o…
On the Role of Coronal Shocks for Accelerating Solar Energetic Electrons
Kouloumvakos, Athanasios; Dresing, Nina; Vainio, Rami +1 more
We study the role of coronal mass ejection (CME) driven shocks in the acceleration of solar energetic electrons. Using observations by the two STEREO spacecraft, we correlate electron peak intensities of solar energetic particle events measured in situ with various parameters of the associated coronal shocks. These shock parameters were derived by…
The Number Densities and Stellar Populations of Massive Galaxies at 3 < z < 6: A Diverse, Rapidly Forming Population in the Early Universe
Muzzin, Adam; Forrest, Ben; Marchesini, Danilo +9 more
We present the census of massive (log(M */M ⊙) > 11) galaxies at 3 < z < 6 identified over the COSMOS/UltraVISTA Ultra-Deep field stripes: consisting of ≈100 and ≈20 high-confidence candidates at 3 < z < 4 and 4 < z < 6, respectively. The 3 < z < 4 population is comprised of post-starburst, UV-star-…
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 …