Search Publications
Comparison between the Logotropic and ΛCDM models at the cosmological scale
Kumar, Suresh; Chavanis, Pierre-Henri
We perform a detailed comparison between the Logotropic model [P.H. Chavanis, Eur. Phys. J. Plus, 130 (2015)] and the ΛCDM model. These two models behave similarly at large (cosmological) scales up to the present. Differences will appear only in the far future, in about 25 Gyrs, when the Logotropic Universe becomes phantom while the ΛCDM Universe …
Reaching the peak of the quasar spectral energy distribution - II. Exploring the accretion disc, dusty torus and host galaxy
Done, Chris; Elvis, Martin; McDowell, Jonathan C. +3 more
We continue our study of the spectral energy distributions (SEDs) of 11 active galactic nuclei (AGN) at 1.5 < z < 2.2, with optical-near-infrared (NIR) spectra, X-ray data and mid-IR photometry. In a previous paper, we presented the observations and models; in this paper, we explore the parameter space of these models. We first quantify unce…
Observations and Modelling of the Pre-flare Period of the 29 March 2014 X1 Flare
Long, D. M.; Harra, L. K.; Matthews, S. A. +3 more
On 29 March 2014, NOAA Active Region (AR) 12017 produced an X1 flare that was simultaneously observed by an unprecedented number of observatories. We have investigated the pre-flare period of this flare from 14:00 UT until 19:00 UT using joint observations made by the Interface Region Imaging Spectrometer (IRIS) and the Hinode Extreme Ultraviolet …
Recovering galaxy cluster gas density profiles with XMM-Newton and Chandra
Arnaud, M.; Pointecouteau, E.; Pratt, G. W. +6 more
We examined the reconstruction of galaxy cluster radial density profiles obtained from Chandra and XMM-Newton X-ray observations, using high quality data for a sample of twelve objects covering a range of morphologies and redshifts. By comparing the results obtained from the two observatories and by varying key aspects of the analysis procedure, w…
Witnessing the reionization history using Cosmic Microwave Background observation from Planck
Hazra, Dhiraj Kumar; Smoot, George F.
We constrain the history of reionization using the data from Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization anisotropy observations. We also use prior constraints on the reionization history at redshifts ~7-8 obtained from Lyman-α emission observations. Using the free electron fractions at different redshifts as free pa…
The Mars diffuse aurora: A model of ultraviolet and visible emissions
Gérard, J. -C.; Soret, L.; Shematovich, V. I. +2 more
A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar activity on several occasions from the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet a…
Discovery of a Satellite of the Large Trans-Neptunian Object (225088) 2007 OR10
Pál, András; Vinkó, József; Marton, Gábor +6 more
2007 OR10 is currently the third largest known dwarf planet in the trans-Neptunian region, with an effective radiometric diameter of ∼1535 km. It has a slow rotation period of ∼45 hr that was suspected to be caused by tidal interactions with a satellite undetected at that time. Here, we report on the discovery of a likely moon of 2007 O…
Ion-Scale Wave Properties and Enhanced Ion Heating Across the Low-Latitude Boundary Layer During Kelvin-Helmholtz Instability
Nykyri, K.; Moore, T. W.; Dimmock, A. P.
In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn sector, the cold-component ions are more abundant and hotter by 30-40% when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetr…
Kinematics and properties of the central molecular zone as probed with [C II]
Morris, M. R.; Goldsmith, P. F.; Langer, W. D. +2 more
Context. The Galactic central molecular zone (CMZ) is a region containing massive and dense molecular clouds, with dynamics driven by a variety of energy sources including a massive black hole. It is thus the nearest template for understanding physical processes in extragalactic nuclei. The CMZ's neutral interstellar gas has been mapped spectrally…
The kinematic signature of the Galactic warp in Gaia DR1. I. The Hipparcos subsample
Lattanzi, M. G.; Drimmel, R.; Poggio, E. +2 more
Context. The mechanism responsible for the warp of our Galaxy, as well as its dynamical nature, continues to remain unknown. With the advent of high precision astrometry, new horizons have been opened for detecting the kinematics associated with the warp and for constraining possible warp formation scenarios for the Milky Way.
Aims: The aim o…