Search Publications
Terrestrial OH nightglow measurements during the Rosetta flyby
Piccioni, G.; Capaccioni, F.; Soret, L. +5 more
We present a study of the terrestrial hydroxyl nightglow emissions observed with the Visible and Infrared Thermal Imaging Spectrometer on board the Rosetta mission. During these observations, the OH Δv = 1 and 2 sequences were measured simultaneously. This allowed investigating the relative population of the v = 1 to 9 vibrational levels by using …
Electron Density of Active Region Outflows Measured by the EUV Imaging Spectrometer on board Hinode
Kitagawa, N.; Yokoyama, T.
In order to better understand the nature of active region outflows, the electron density was measured by using a density-sensitive line pair, Fe xiv 264.78 Å/274.20 Å. Because coronal line profiles of the outflow region are composed of a major component with a Doppler shift of ≤slant 10 km {{s}-1} and a minor component (enhanced blue wi…
Unveiling acoustic physics of the CMB using nonparametric estimation of the temperature angular power spectrum for Planck
Shafieloo, Arman; Aghamousa, Amir; Souradeep, Tarun +1 more
Estimation of the angular power spectrum is one of the important steps in Cosmic Microwave Background (CMB) data analysis. Here, we present a nonparametric estimate of the temperature angular power spectrum for the Planck 2013 CMB data. The method implemented in this work is model-independent, and allows the data, rather than the model, to dictate…
Interaction of Low-Activity Comets with the Solar Wind
Baranov, Vladimir B.; Alexashov, Dmitry B.; Lebedev, Michail G.
The solar wind flow around a cometary atmosphere is calculated using the three-dimensional magnetohydrodynamic model developed by the authors. Emphasis is placed on the case of low-activity comets in which some special features, both quantitative and qualitative, are inherent. The behavior of the flowfield and the magnetic field disturbed by the c…
Planck data and ultralight axions
Csáki, Csaba; Kaloper, Nemanja; Terning, John
We examine the effects of photon-axion mixing on the CMB. We show that if there are very underdense regions between us and the last scattering surface which contain coherent magnetic fields (whose strength can be orders of magnitude weaker than the current bounds), then photon-axion mixing can induce observable deviations in the CMB spectrum. Spec…
Mass-concentration relation and weak lensing peak counts
Maoli, R.; Scaramella, R.; Camera, S. +3 more
Context. The statistics of peaks in weak lensing convergence maps is a promising tool for investigating both the properties of dark matter haloes and constraining the cosmological parameters.
Aims: We study how the number of detectable peaks and its scaling with redshift depend upon the cluster's dark matter halo profiles and use peak statist…
A Minimum Energy Fit Method to Reconstruct Photospheric Velocity and Magnetic Diffusivity in Active Regions from Observed Magnetograms and Dopplergrams
Tremblay, Benoit; Vincent, Alain
We introduce MEF-R, a generalization of the minimum energy fit (MEF; Longcope, Astrophys. J.612, 1181, 2004) to a non-ideal (resistive) gas. The new technique requires both vector magnetograms and Doppler velocities as input fields. However, in the case of active regions observed only with the Michelson-Doppler Imager (MDI) onboard the Solar and H…
Using the transit of Venus to probe the upper planetary atmosphere
Piccioni, Giuseppe; Reale, Fabio; Widemann, Thomas +3 more
During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultr…
Simulating charge transport to understand the spectral response of Swept Charge Devices
Narendranath, S.; Sreekumar, P.; Athiray, P. S. +1 more
Context. Swept Charge Devices (SCD) are novel X-ray detectors optimized for improved spectral performance without any demand for active cooling. The Chandrayaan-1 X-ray Spectrometer (C1XS) experiment onboard the Chandrayaan-1 spacecraft used an array of SCDs to map the global surface elemental abundances on the Moon using the X-ray fluorescence (X…
In situ magnetotail magnetic flux calculation
Gordeev, E.; Shukhtina, M. A.
We explore two new modifications of the magnetotail magnetic flux (F) calculation algorithm based on the Petrinec and Russell (1996) (PR96) approach of the tail radius determination. Unlike in the PR96 model, the tail radius value is calculated at each time step based on simultaneous magnetotail and solar wind observations. Our former algorithm, d…