Search Publications
Discovery of Coherent Pulsations from the Ultraluminous X-Ray Source NGC 7793 P13
Harrison, F. A.; Ptak, A.; Stern, D. +12 more
We report the detection of coherent pulsations from the ultraluminous X-ray source (ULX) NGC 7793 P13. The ≈0.42 s nearly sinusoidal pulsations were initially discovered in broadband X-ray observations using XMM-Newton and NuSTAR taken in 2016. We subsequently also found pulsations in archival XMM-Newton data taken in 2013 and 2014. The significan…
The MUSCLES Treasury Survey. I. Motivation and Overview
Loyd, R. O. Parke; Kowalski, Adam F.; Hawley, Suzanne L. +19 more
Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun-Earth system provides a good framework f…
The Tight Relation between X-Ray and Ultraviolet Luminosity of Quasars
Lusso, E.; Risaliti, G.
The observed relation between the soft X-ray and the optical-ultraviolet emission in active galactic nuclei (AGNs) is nonlinear and it is usually parametrized as a dependence between the logarithm of the monochromatic luminosity at 2500 Å and at 2 keV. Previous investigations have found that the dispersion of this relation is rather high (∼0.35-0.…
Discovery of a Galaxy Cluster with a Violently Starbursting Core at z = 2.506
Daddi, Emanuele; Tan, Qinghua; Liu, Daizhong +17 more
We report the discovery of a remarkable concentration of massive galaxies with extended X-ray emission at z spec = 2.506, which contains 11 massive (M * ≳ 1011 M ⊙) galaxies in the central 80 kpc region (11.6σ overdensity). We have spectroscopically confirmed 17 member galaxies with 11 from CO and the re…
The MUSCLES Treasury Survey. III. X-Ray to Infrared Spectra of 11 M and K Stars Hosting Planets
Redfield, Seth; Brown, Alexander; France, Kevin +8 more
We present a catalog of panchromatic spectral energy distributions (SEDs) for 7 M and 4 K dwarf stars that span X-ray to infrared wavelengths (5 Å -5.5 µm). These SEDs are composites of Chandra or XMM-Newton data from 5-∼50 Å, a plasma emission model from ∼50-100 Å, broadband empirical estimates from 100-1170 Å, Hubble Space Telescope data f…
A New Population of Compton-thick AGNs Identified Using the Spectral Curvature above 10 keV
Harrison, F. A.; Stern, D.; Alexander, D. M. +19 more
We present a new metric that uses the spectral curvature (SC) above 10 keV to identify Compton-thick active galactic nuclei (AGNs) in low-quality Swift/Burst Alert Telescope (BAT) X-ray data. Using NuSTAR, we observe nine high SC-selected AGNs. We find that high-sensitivity spectra show that the majority are Compton-thick (78% or 7/9) and the rema…
Classification and Ranking of Fermi LAT Gamma-ray Sources from the 3FGL Catalog using Machine Learning Techniques
Marelli, M.; Saz Parkinson, P. M.; Falcone, A. D. +3 more
We apply a number of statistical and machine learning techniques to classify and rank gamma-ray sources from the Third Fermi Large Area Telescope Source Catalog (3FGL), according to their likelihood of falling into the two major classes of gamma-ray emitters: pulsars (PSR) or active galactic nuclei (AGNs). Using 1904 3FGL sources that have been id…
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…
IC 751: A New Changing Look AGN Discovered by NuSTAR
Harrison, F. A.; Boggs, S.; Stern, D. +12 more
We present results of five Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the type 2 active galactic nucleus (AGN) in IC 751, three of which were performed simultaneously with XMM-Newton or Swift/X-Ray Telescope. We find that the nuclear X-ray source underwent a clear transition from a Compton-thick ({N}{{H}}≃ 2× {10}
An Iron K Component to the Ultrafast Outflow in NGC 1313 X-1
Harrison, F. A.; Stern, D.; Fabian, A. C. +8 more
We present the detection of an absorption feature at E={8.77}-0.06+0.05 keV in the combined X-ray spectrum of the ultraluminous X-ray source NGC 1313 X-1 observed with XMM-Newton and NuSTAR, significant at the 3σ level. If associated with blueshifted ionized iron, the implied outflow velocity is ∼0.2c for Fe xxvi, or ∼0.25c f…