Search Publications
A massive, quiescent, population II galaxy at a redshift of 2.1
Siana, Brian; van Dokkum, Pieter G.; Choi, Jieun +7 more
Unlike spiral galaxies such as the Milky Way, the majority of the stars in massive elliptical galaxies were formed in a short period early in the history of the Universe. The duration of this formation period can be measured using the ratio of magnesium to iron abundance ([Mg/Fe]) in spectra, which reflects the relative enrichment by core-collapse…
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…
Global seismology of the Sun
Basu, Sarbani
The seismic study of the Sun and other stars offers a unique window into the interior of these stars. Thanks to helioseismology, we know the structure of the Sun to admirable precision. In fact, our knowledge is good enough to use the Sun as a laboratory. We have also been able to study the dynamics of the Sun in great detail. Helioseismic data al…
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…
MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397. I. The first comprehensive HRD of a globular cluster
Bacon, Roland; Brinchmann, Jarle; Weilbacher, Peter M. +8 more
Aims: We demonstrate the high multiplex advantage of crowded field 3D spectroscopy with the new integral field spectrograph MUSE by means of a spectroscopic analysis of more than 12 000 individual stars in the globular cluster NGC 6397.
Methods: The stars are deblended with a point spread function fitting technique, using a photometric r…
The XXL Survey. XIII. Baryon content of the bright cluster sample
Smith, G. P.; Chiappetti, L.; Paltani, S. +20 more
Traditionally, galaxy clusters have been expected to retain all the material accreted since their formation epoch. For this reason, their matter content should be representative of the Universe as a whole, and thus their baryon fraction should be close to the Universal baryon fraction Ωb/ Ωm. We make use of the sample of the …
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…
The evolution of the equivalent width of the Hα emission line and specific star formation rate in star-forming galaxies at 1 < z < 5
Cullen, F.; McLure, R. J.; Dunlop, J. S. +3 more
We present the results of a study which uses spectral energy distribution (SED) fitting to investigate the evolution of the equivalent width (EW) of the Hα emission line in star-forming galaxies over the redshift interval 1 < z < 5. After first demonstrating the ability of our SED-fitting technique to recover EW(Hα) using a sample of galaxie…
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…