Search Publications
The Nuclear Cluster of the Milky Way: Total Mass and Luminosity
Genzel, R.; Gillessen, S.; Eisenhauer, F. +6 more
We obtain the basic properties of the nuclear cluster of the Milky Way. First, we investigate the structural properties by constructing a stellar density map of the central 1000″ using extinction-corrected old star counts from VISTA, WFC3/IR, and VLT/NACO data. We describe the data using two components. The inner, slightly flattened (axis ratio of…
Predicting Coronal Mass Ejections Using Machine Learning Methods
Ilonidis, S.; Bobra, M. G.
Of all the activity observed on the Sun, two of the most energetic events are flares and coronal mass ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true. Despite advances in numerical modeling, it is still unclear which circumstances will produce a CME. Therefore, it is wo…
Compressive Coherent Structures at Ion Scales in the Slow Solar Wind
Maksimovic, M.; Alexandrova, O.; Kasper, J. C. +5 more
We present a study of magnetic field fluctuations in a slow solar wind stream, close to ion scales, where an increase of the level of magnetic compressibility is observed. Here, the nature of these compressive fluctuations is found to be characterized by coherent structures. Although previous studies have shown that current sheets can be considere…
The Most Luminous Heavily Obscured Quasars Have a High Merger Fraction: Morphological Study of WISE-selected Hot Dust-obscured Galaxies
Fang, Guanwen; Yang, Jun; Fan, Lulu +6 more
Previous studies have shown that Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick active galactic nuclei (AGNs). High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host…
MOST Observations of Our Nearest Neighbor: Flares on Proxima Centauri
Davenport, James R. A.; Sasselov, Dimitar; Kipping, David M. +2 more
We present a study of white-light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite Microvariability and Oscillations of STars. Using 37.6 days of monitoring data from 2014 to 2015, we have detected 66 individual flare events, the largest number of white-light flares observed to date on Proxima Cen. Flare energie…
Panchromatic Hubble Andromeda Treasury. XVI. Star Cluster Formation Efficiency and the Clustered Fraction of Young Stars
Bell, Eric F.; Dolphin, Andrew E.; Skillman, Evan D. +10 more
We use the Panchromatic Hubble Andromeda Treasury survey data set to perform spatially resolved measurements of star cluster formation efficiency (Γ), the fraction of stellar mass formed in long-lived star clusters. We use robust star formation history and cluster parameter constraints, obtained through color-magnitude diagram analysis of resolved…
X-Ray Detected Active Galactic Nuclei in Dwarf Galaxies at 0 < z < 1
Silverman, J. D.; Hickox, R. C.; Greene, J. E. +6 more
We present a sample of accreting supermassive black holes (SMBHs) in dwarf galaxies at z\lt 1. We identify dwarf galaxies in the NEWFIRM Medium Band Survey with stellar masses of {M}\star \lt 3× {10}9 {M}⊙ that have spectroscopic redshifts from the DEEP2 survey and lie within the region covered by deep (flux limit…
Magnetar-like Activity from the Central Compact Object in the SNR RCW103
Rea, N.; Esposito, P.; De Luca, A. +4 more
The 6.67 hr periodicity and the variable X-ray flux of the central compact object (CCO) at the center of the supernova remnant RCW 103, named 1E 161348-5055, have been always difficult to interpret within the standard scenarios of an isolated neutron star (NS) or a binary system. On 2016 June 22, the Burst Alert Telescope (BAT) on board Swift dete…
Morphology and Molecular Gas Fractions of Local Luminous Infrared Galaxies as a Function of Infrared Luminosity and Merger Stage
Sanders, D. B.; Kim, D. -C.; Mirabel, I. F. +8 more
We present a new, detailed analysis of the morphologies and molecular gas fractions (MGFs) for a complete sample of 65 local luminous infrared galaxies from Great Observatories All-Sky Luminous Infrared Galaxies (LIRG) Survey using high resolution I-band images from The Hubble Space Telescope, the University of Hawaii 2.2 m Telescope and the Pan-S…
Simulations of the Mg II k and Ca II 8542 lines from an Alfvén Wave-heated Flare Chromosphere
Kerr, Graham S.; Fletcher, Lyndsay.; Russell, Alexander J. B. +1 more
We use radiation hydrodynamic simulations to examine two models of solar flare chromospheric heating: Alfvén wave dissipation and electron beam collisional losses. Both mechanisms are capable of strong chromospheric heating, and we show that the distinctive atmospheric evolution in the mid-to-upper chromosphere results in Mg II k-line emission tha…