Search Publications
The Formation of IRIS Diagnostics. VI. The Diagnostic Potential of the C II Lines at 133.5 nm in the Solar Atmosphere
De Pontieu, Bart; Carlsson, Mats; Leenaarts, Jorrit +1 more
We use 3D radiation magnetohydrodynamic models to investigate how the thermodynamic quantities in the simulation are encoded in observable quantities, thus exploring the diagnostic potential of the C ii 133.5 nm lines. We find that the line core intensity is correlated with the temperature at the formation height but the correlation is rather weak…
Spitzer infrared spectrograph point source classification in the Small Magellanic Cloud
van Loon, J. Th.; Antoniou, V.; Szczerba, R. +16 more
The Magellanic Clouds are uniquely placed to study the stellar contribution to dust emission. Individual stars can be resolved in these systems even in the mid-infrared, and they are close enough to allow detection of infrared excess caused by dust. We have searched the Spitzer Space Telescope data archive for all Infrared Spectrograph (IRS) stari…
Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data
Väliviita, Jussi; Palmgren, Elina
We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological wCDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is…
The Orion fingers: Near-IR adaptive optics imaging of an explosive protostellar outflow
Ginsburg, Adam; Youngblood, Allison; Bally, John +1 more
Aims: Adaptive optics (AO) images are used to test the hypothesis that the explosive BN/KL outflow from the Orion OMC1 cloud core was powered by the dynamical decay of a non-hierarchical system of massive stars.
Methods: Narrow-band H2, [Fe ii], and broad-band Ks obtained with the Gemini South multi-conjugate AO sys…
Rosetta observations of solar wind interaction with the comet 67P/Churyumov-Gerasimenko
Behar, E.; Goldstein, R.; Mokashi, P. +7 more
Context. The Rosetta spacecraft arrived at the comet 67P/Churyumov-Gerasimenko on August 6, 2014, which has made it possible to perform the first study of the solar wind interacting with the coma of a weakly outgassing comet.
Aims: It is shown that the solar wind experiences large deflections (>45°) in the weak coma. The average ion veloci…
ALMA Observations of Warm Dense Gas in NGC 1614—Breaking of the Star Formation Law in the Central Kiloparsec
Sanders, D. B.; Inami, H.; Murphy, E. J. +20 more
We present ALMA Cycle-0 observations of the CO (6-5) line emission and of the 435 µm dust continuum emission in the central kiloparsec of NGC 1614, a local luminous infrared galaxy at a distance of 67.8 Mpc (1{\prime \prime }= 329 pc). The CO emission is well resolved by the ALMA beam (0.''26 × 0.''20) into a circumnuclear ring, w…
Combining power spectrum and bispectrum measurements to detect oscillatory features
Liguori, M.; Shellard, E. P. S.; Fergusson, J. R. +1 more
The simplest inflationary models present us with few observable parameters to discriminate between them. A detection of features in the spectra of primordial density perturbations could provide valuable insights and lead to stringent tests of models of the early Universe. So far, searches for oscillatory features have not produced statistically si…
FUV Variability of HD 189733. Is the Star Accreting Material From Its Hot Jupiter?
Micela, G.; Sciortino, S.; Pillitteri, I. +3 more
Hot Jupiters are subject to strong irradiation from their host stars and, as a consequence, they do evaporate. They can also interact with the parent stars by means of tides and magnetic fields. Both phenomena have strong implications for the evolution of these systems. Here we present time-resolved spectroscopy of HD 189733 observed with the Cosm…
The NuSTAR Extragalactic Survey: First Direct Measurements of the ≳10 KeV X-Ray Luminosity Function for Active Galactic Nuclei at z>0.1
Harrison, F. A.; Wik, D. R.; Stern, D. +34 more
We present the first direct measurements of the rest-frame 10-40 keV X-ray luminosity function (XLF) of active galactic nuclei (AGNs) based on a sample of 94 sources at 0.1 < z < 3, selected at 8-24 keV energies from sources in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic survey program. Our results are consistent with th…
Circumstellar Dust around AGB Stars and Implications for Infrared Emission from Galaxies
Conroy, Charlie; Johnson, Benjamin D.; Villaume, Alexa
Stellar population synthesis (SPS) models are used to infer many galactic properties including star formation histories, metallicities, and stellar and dust masses. However, most SPS models neglect the effect of circumstellar dust shells around evolved stars and it is unclear to what extent they impact the analysis of spectral energy distributions…