DE FREITAS PACHECO , J.a.

International audience

International audience

International audience

International audience

International audience

New Astronomy, 11, pp. 325-330, http://dx.doi.org./10.1016/j.newast.2005.08.008

Primordial black holes formed in an early postinflation matter-dominated epoch during preheating provide a novel pathway for a source of the dark matter that utilizes known physics in combination with plausible speculations about the role of quantum gravity. Two cases are considered here: survival of Planck-scale relics and an early universe...

International Journal of Modern Physics D, 15, pp. 153-163, http://dx.doi.org./10.1142/s0218271806007584

Astronomy and Astrophysics, 488, pp. 845-851, http://dx.doi.org./10.1051/0004-6361:09711

Classical and Quantum Gravity, 24, pp. 5427-5433, http://dx.doi.org./10.1088/0264-9381/24/22/007

Physical Review D, 77, p. 64023, http://dx.doi.org./10.1103/PhysRevD.77.064023

International audience

A massive gravity theory was proposed by Visser in the late 1990s. This theory, based on a background metric b(alpha beta) and on an usual dynamical metric g(alpha beta) has the advantage of being free of ghosts as well as discontinuities present in other massive theories proposed in the past. In the present investigation, the equations of...

Cosmological N-body simulations were performed to study the evolution of the phase-space density Q = ρ/σ 3 of dark matter haloes. No significant differences in the scale relations Q ∝ σ −2.1 or Q ∝ M −0.82 are seen for the 'cold' or 'warm' dark matter models. The follow-up of individual haloes from z = 10 up to the present time indicate the...

International Journal of Modern Physics D, 16, pp. 313-318, http://dx.doi.org./10.1142/s0218271807010067

New calibrations of spectrophotometric indices of elliptical galaxies as functions of spectrophotometric indices are presented, permitting estimates of mean stellar population ages and metallicities. These calibrations are based on evolutionary models including a two-phase interstellar medium, infall and a galactic wind. Free parameters were...

International audience

In a recent paper we have shown that a minimally coupled, self-interacting scalar field of mass m can form black holes of mass $M=\sqrt{3}/(4m)$ (in Planck units). If dark matter is composed by axions, they can form miniclusters that for QCD axions have masses below this value. In this work it is shown that for a scenario in which the axion...

International Journal of Modern Physics A, 21, pp. 43-55, http://dx.doi.org./10.1142/s0217751x06025055

International audience

International audience

General Relativity and Gravitation, 40, pp. 1593-1602, http://dx.doi.org./10.1007/s10714-007-0562-8

First mid-infrared images of a sample of AGB and post-AGB carbon stars (V Hya, IRC +10216, CIT 6 and Roberts 22) obtained at the ESO-La Silla Observatory (Chile) are reported. CIT 6 presents a cometary-like feature clearly seen in the 9.7 µm image, Roberts 22 shows an envelope slightly elongated in the northeast direction while images of V Hya...

International audience

First mid-infrared images of a sample of AGB and post-AGB carbon stars (V Hya, IRC +10216, CIT 6 and Roberts 22) obtained at the ESO-La Silla Observatory (Chile) are reported. CIT 6 presents a cometary-like feature clearly seen in the 9.7 µm image, Roberts 22 shows an envelope slightly elongated in the northeast direction while images of V Hya...