Search Publications
The Broadband Spectral Variability of MCG-6-30-15 Observed by NuSTAR and XMM-Newton
Harrison, F. A.; Cappi, M.; Guainazzi, M. +19 more
MCG-6-30-15, at a distance of 37 Mpc (z = 0.008), is the archetypical Seyfert 1 galaxy showing very broad Fe Kα emission. We present results from a joint NuSTAR and XMM-Newton observational campaign that, for the first time, allows a sensitive, time-resolved spectral analysis from 0.35 keV up to 80 keV. The strong variability of the source is best…
Confirmation of Circumstellar Phosphine
Teyssier, D.; Cernicharo, J.; Encrenaz, P. +2 more
Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH3 in IRC +10216 using the HIFI instrument on bo…
The Albedo-Color Diversity of Transneptunian Objects
Lellouch, Emmanuel; Lacerda, Pedro; Guilbert-Lepoutre, Aurélie +9 more
We analyze albedo data obtained using the Herschel Space Observatory that reveal the existence of two distinct types of surface among midsized trans-Neptunian objects. A color-albedo diagram shows two large clusters of objects, one redder and higher albedo and another darker and more neutrally colored. Crucially, all objects in our sample located …
The Radiated Energy Budget of Chromospheric Plasma in a Major Solar Flare Deduced from Multi-wavelength Observations
Chamberlin, Phillip C.; Milligan, Ryan O.; Kerr, Graham S. +7 more
This paper presents measurements of the energy radiated by the lower solar atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare (SOL2011-02-15T01:56) in response to an injection of energy assumed to be in the form of nonthermal electrons. Hard X-ray observations from RHESSI were used to track the evolution of the paramete…
Uncovering the Putative B-star Binary Companion of the SN 1993J Progenitor
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Chandra, Poonam +9 more
The Type IIb supernova (SN) 1993J is one of only a few stripped-envelope SNe with a progenitor star identified in pre-explosion images. SN IIb models typically invoke H envelope stripping by mass transfer in a binary system. For the case of SN 1993J, the models suggest that the companion grew to 22 M ⊙ and became a source of ultraviolet…
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 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…
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…
A Blue Point Source at the Location of Supernova 2011dh
Van Dyk, Schuyler D.; Nomoto, Ken'ichi; Quimby, Robert M. +7 more
We present Hubble Space Telescope (HST) observations of the field of the Type IIb supernova (SN) 2011dh in M51 performed at ≈1161 rest-frame days after explosion using the Wide Field Camera 3 and near-UV filters F225W and F336W. A star-like object is detected in both bands and the photometry indicates it has negative (F225W - F336W) color. The obs…