Search Publications
The Discovery of the Most Distant Known Type Ia Supernova at Redshift 1.914
Ferguson, Henry C.; Grogin, Norman A.; Weiner, Benjamin J. +22 more
We present the discovery of a Type Ia supernova (SN) at redshift z = 1.914 from the CANDELS multi-cycle treasury program on the Hubble Space Telescope (HST). This SN was discovered in the infrared using the Wide-Field Camera 3, and it is the highest-redshift Type Ia SN yet observed. We classify this object as a SN Ia by comparing its light curve a…
Far-ultraviolet Detection of the Suspected Subdwarf Companion to the Be Star 59 Cygni
Gies, Douglas R.; Peters, Geraldine J.; Pewett, Tiffany D. +2 more
We report on the detection of a hot subdwarf component in the Be binary system, 59 Cygni. The spectral signature is found in cross-correlation functions of photospheric model spectra with far-ultraviolet spectra obtained by the International Ultraviolet Explorer Satellite, and we used radial velocities from the cross-correlation functions to deter…
The Progenitor of Supernova 2011dh has Vanished
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Cenko, S. Bradley +7 more
We conducted Hubble Space Telescope (HST) Snapshot observations of the Type IIb supernova (SN) 2011dh in M51 at an age of ~641 days with the Wide Field Camera 3. We find that the yellow supergiant star, clearly detected in pre-SN HST images, has disappeared, implying that this star was almost certainly the progenitor of the SN. Interpretation of t…
Accurate determination of accretion and photospheric parameters in young stellar objects: The case of two candidate old disks in the Orion Nebula Cluster
Robberto, M.; Da Rio, N.; Testi, L. +5 more
Context. Current planet formation models are largely based on the observational constraint that protoplanetary disks have a lifetime of ~3 Myr. Recent studies, however, report the existence of pre-main-sequence stars with signatures of accretion (strictly connected with the presence of circumstellar disks) and photometrically determined ages of 30…
Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U1630-47
Miller-Jones, James C. A.; Tzioumis, Tasso; Migliari, Simone +2 more
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than elec…
X-ray exploration of the outskirts of the nearby Centaurus cluster using Suzaku and Chandra
Simionescu, A.; Fabian, A. C.; Sanders, J. S. +2 more
We present Suzaku observations of the Centaurus cluster out to 0.95r200, taken along a strip to the north-west. We have also used congruent Chandra observations of the outskirts to resolve point sources down to a threshold flux around seven times lower than that achievable with just Suzaku data, considerably reducing the systematic unce…
Discovery of a magnetic field in the rapidly rotating O-type secondary of the colliding-wind binary HD 47129 (Plaskett's star)
Martins, F.; Wade, G. A.; Neiner, C. +14 more
We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for…
The Importance of Physical Models for Deriving Dust Masses and Grain Size Distributions in Supernova Ejecta. I. Radiatively Heated Dust in the Crab Nebula
Temim, Tea; Dwek, Eli
Recent far-infrared (IR) observations of supernova remnants (SNRs) have revealed significantly large amounts of newly condensed dust in their ejecta, comparable to the total mass of available refractory elements. The dust masses derived from these observations assume that all the grains of a given species radiate at the same temperature, regardles…
Depleted Galaxy Cores and Dynamical Black Hole Masses
Saglia, R. P.; Nowak, N.; Thomas, J. +4 more
Shallow cores in bright, massive galaxies are commonly thought to be the result of scouring of stars by mergers of binary supermassive black holes. Past investigations have suggested correlations between the central black hole mass and the stellar light or mass deficit in the core, using proxy measurements of M BH or stellar mass-to-lig…
Albedo Properties of Main Belt Asteroids Based on the All-Sky Survey of the Infrared Astronomical Satellite AKARI
Hasegawa, Sunao; Usui, Fumihiko; Ootsubo, Takafumi +5 more
We present an analysis of the albedo properties of main belt asteroids (MBAs) detected by the All-Sky Survey of the infrared astronomical satellite AKARI. The characteristics of 5120 asteroids detected by the survey, including their sizes and albedos, were cataloged in the Asteroid Catalog Using AKARI (AcuA). Size and albedo measurements were base…