Search Publications
Constraining Neutrino Cooling Using the Hot White Dwarf Luminosity Function in the Globular Cluster 47 Tucanae
Hansen, Brad M. S.; Heyl, Jeremy; Richer, Harvey +3 more
We present Hubble Space Telescope observations of the upper part ({T}{eff}\gt {10}4 K) of the white dwarf cooling sequence in the globular cluster 47 Tucanae and measure a luminosity function of hot white dwarfs. Comparison with previous determinations from large-scale field surveys indicates that the previously determined pl…
The Properties of Solar Energetic Particle Event-Associated Coronal Mass Ejections Reported in Different CME Catalogs
Cane, H. V.; Richardson, I. G.; von Rosenvinge, T. T.
We compare estimates of the speed and width of coronal mass ejections (CMEs) in several catalogs for the CMEs associated with ∼ 200 solar energetic particle (SEP) events in 2006 - 2013 that included 25 MeV protons. The catalogs used are: CDAW, CACTUS, SEEDS, and CORIMP, all derived from observations by the LASCO coronagraphs on the SOHO spacecraft…
Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy⋆⋆⋆
Fritz, J.; Cooray, A.; Lebouteiller, V. +15 more
We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in the nearby, edge-on spiral galaxy, NGC 891: [Cii] 158 µm, [Nii] 122, 205 µm, [Oi] 63, 145 µm, and [Oiii] 88 µm. We find that the photoelectric heating efficiency of the gas, traced via the ([Cii]+[Oi]63)/FTIR ratio…
GTC OSIRIS transiting exoplanet atmospheric survey: detection of potassium in HAT-P-1b from narrow-band spectrophotometry
Pont, F.; Fortney, J. J.; Lecavelier des Etangs, A. +7 more
We present the detection of potassium in the atmosphere of HAT-P-1b using optical transit narrow-band photometry. The results are obtained using the 10.4-m Gran Telescopio Canarias together with the OSIRIS instrument in tunable filter imaging mode. We observed four transits, two at continuum wavelengths outside the potassium feature, at 6792 and 8…
Integral Field Spectroscopy of AGN Absorption Outflows: Mrk 509 and IRAS F04250-5718
Rupke, David S. N.; Arav, Nahum; Liu, Guilin
Ultraviolet (UV) absorption lines provide abundant spectroscopic information enabling the probe of the physical conditions in active galactic nucleus (AGN) outflows, but the outflow radii (and the energetics consequently) can only be determined indirectly. We present the first direct test of these determinations using integral field unit (IFU) spe…
3C 273 with NuSTAR: Unveiling the Active Galactic Nucleus
Hailey, Charles J.; Fabian, Andrew C.; Brenneman, Laura W. +17 more
We present results from a 244 ks NuSTAR observation of 3C 273 obtained during a cross-calibration campaign with the Chandra, INTEGRAL, Suzaku, Swift, and XMM-Newton observatories. We show that the spectrum, when fit with a power-law model using data from all observatories except INTEGRAL over the 1-78 keV band, leaves significant residuals in the …
Quantifying the Difference Between the Flux-Tube Expansion Factor at the Source Surface and at the Alfvén Surface Using a Global MHD Model for the Solar Wind
Cohen, O.
The potential-field approximation has been providing a fast and computationally inexpensive estimation for the solar corona's global magnetic-field geometry for several decades. In contrast, more physics-based global magnetohydrodynamic (MHD) models have been used for a similar purpose, while being much more computationally expensive. Here, we inv…
Analysis of the radiative budget of the Venusian atmosphere based on infrared Net Exchange Rate formalism
Lebonnois, Sébastien; Eymet, Vincent; Vatant d'Ollone, Jan +1 more
A detailed one-dimensional analysis of the energy balance in Venus atmosphere is proposed in this work, based on the Net Exchange Rate formalism that allows the identification in each altitude region of the dominant energy exchanges controlling the temperature. Well-known parameters that control the temperature profile are the solar flux depositio…
Is Flux Rope a Necessary Condition for the Progenitor of Coronal Mass Ejections?
Ouyang, Y.; Yang, K.; Chen, P. F.
A magnetic flux rope structure is believed to exist in most coronal mass ejections (CMEs). However, it has been long debated whether the flux rope exists before eruption or if it is formed during eruption via magnetic reconnection. The controversy has continued because of our lack of routine measurements of the magnetic field in the pre-eruption s…
Robustness of cosmic neutrino background detection in the cosmic microwave background
Verde, Licia; Tram, Thomas; Cuesta, Antonio J. +9 more
The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already propos…