Search Publications
Weighing "El Gordo" with a Precision Scale: Hubble Space Telescope Weak-lensing Analysis of the Merging Galaxy Cluster ACT-CL J0102-4915 at z = 0.87
Sifón, Cristóbal; Hughes, John P.; Barrientos, L. Felipe +5 more
We present a Hubble Space Telescope weak-lensing study of the merging galaxy cluster "El Gordo" (ACT-CL J0102-4915) at z = 0.87 discovered by the Atacama Cosmology Telescope (ACT) collaboration as the strongest Sunyaev-Zel'dovich decrement in its ~1000 deg2 survey. Our weak-lensing analysis confirms that ACT-CL J0102-4915 is indeed an e…
Rejecting Proposed Dense Matter Equations of State with Quiescent Low-mass X-Ray Binaries
Guillot, Sebastien; Rutledge, Robert E.
Neutrons stars are unique laboratories for discriminating between the various proposed equations of state of matter at and above nuclear density. One sub-class of neutron stars—those inside quiescent low-mass X-ray binaries (qLMXBs)—produce a thermal surface emission from which the neutron star radius (R NS) can be measured, using the w…
The effect of accretion on the measurement of neutron star mass and radius in the low-mass X-ray binary 4U 1608-52
Suleimanov, Valery F.; Poutanen, Juri; Nättilä, Joonas +4 more
Spectral measurements of thermonuclear (type I) X-ray bursts from low-mass X-ray binaries have been used to measure neutron star (NS) masses and radii. A number of systematic issues affect such measurements and have raised concerns as to the robustness of the methods. We present analysis of the X-ray emission from bursts observed from 4U 1608-52 a…
Observational constraints on slow-roll inflation coupled to a Gauss-Bonnet term
Koh, Seoktae; Lee, Bum-Hoon; Lee, Wonwoo +1 more
We study slow-roll inflation with a Gauss-Bonnet term that is coupled to an inflaton field nonminimally. We investigate the inflationary solutions for a specific type of the nonminimal coupling to the Gauss-Bonnet term and inflaton potential both analytically and numerically. We also calculate the observable quantities such as the power spectra of…
High-resolution, 3D radiative transfer modeling. I. The grand-design spiral galaxy M 51
Lebouteiller, Vianney; Wilson, Christine D.; De Looze, Ilse +20 more
Context. Dust reprocesses about half of the stellar radiation in galaxies. The thermal re-emission by dust of absorbed energy is considered to be driven merely by young stars so is often applied to tracing the star formation rate in galaxies. Recent studies have argued that the old stellar population might be responsible for a non-negligible fract…
The Solar Internetwork. I. Contribution to the Network Magnetic Flux
Gošić, M.; Bellot Rubio, L. R.; Katsukawa, Y. +2 more
The magnetic network (NE) observed on the solar surface harbors a sizable fraction of the total quiet Sun flux. However, its origin and maintenance are not well known. Here we investigate the contribution of internetwork (IN) magnetic fields to the NE flux. IN fields permeate the interior of supergranular cells and show large emergence rates. We u…
Saturn ring seismology: Evidence for stable stratification in the deep interior of Saturn
Fuller, Jim
Seismology allows for direct observational constraints on the interior structures of stars and planets. Recent observations of Saturn's ring system have revealed the presence of density waves within the rings excited by oscillation modes within Saturn, allowing for precise measurements of a limited set of the planet's mode frequencies. We construc…
Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469
Motohara, K.; Skowron, D. M.; Skowron, J. +43 more
A large reverberation-mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for Hβ λ4861 and He II λ4686 and a central black hole mass measurement M BH ≈ 1 × 107 M ⊙, consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our o…
Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654
Harrison, F. A.; Cappi, M.; Fabian, A. C. +20 more
We present a broad-band spectral analysis of the joint XMM-Newton and Nuclear Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron Kα line originating from the innermost regions of the accretion di…
Rapidly growing black holes and host galaxies in the distant Universe from the Herschel Radio Galaxy Evolution Project
Stern, D.; Bauer, F. E.; Ibar, E. +14 more
We present results from a comprehensive survey of 70 radio galaxies at redshifts 1 <z< 5.2 using the PACS and SPIRE instruments on board the Herschel Space Observatory. Combined with existing mid-IR photometry from the Spitzer Space Telescope, published 870 µm photometry, and new observations obtained with LABOCA on the APEX telescope,…