Recherche

Afficher tous les résultats pour

Accueil

Personne

Oleg Ruchayskiy

Cette personne n’est plus à l’EPFL

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (45)

Unidentified Line in X-Ray Spectra of the Andromeda Galaxy and Perseus Galaxy Cluster

Alexey Boyarsky, Oleg Ruchayskiy

We report a weak line at 3.52 +/- 0.02 keV in x-ray spectra of the Andromeda galaxy and the Perseus galaxy cluster observed by the metal-oxide-silicon (MOS) and p-n (PN) CCD cameras of the XMM-Newton telescope. This line is not known as an atomic line in t ...

Amer Physical Soc2014

Potential of the Large Observatory for X-ray Timing telescope for the search for dark matter

Alexey Boyarsky, Oleg Ruchayskiy

Large observatory for x-ray timing (LOFT) is a concept of a next-generation x-ray telescope considered in the context of the "Cosmic Vision" program of the European Space Agency. The Large Area Detector on board of LOFT will be a collimator-type telescope ...

American Physical Society2014

Tag Recommendation for Large-Scale Ontology-Based Information Systems

Philippe Cudré-Mauroux, Karl Aberer, Alexey Boyarsky, Oleg Ruchayskiy, Roman Prokofyev

We tackle the problem of improving the relevance of automatically selected tags in large-scale ontology-based information systems. Contrary to traditional settings where tags can be chosen arbitrarily, we focus on the problem of recommending tags (e.g., co ...

Springer2012

Self-Consistent Evolution of Magnetic Fields and Chiral Asymmetry in the Early Universe

Alexey Boyarsky, Oleg Ruchayskiy

We show that the evolution of magnetic fields in a primordial plasma, filled with standard model particles at temperatures T greater than or similar to 10 MeV, is strongly affected by the chiral anomaly-an effect previously neglected. Although reactions, e ...

2012

ORIGIN: metal creation and evolution from the cosmic dawn

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy, Douglas Cameron Watson, Simone Campana

ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high-spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical conditions of all abundant elements ...

Springer2012

Long-Range Magnetic Fields in the Ground State of the Standard Model Plasma

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy

In thermal equilibrium the ground state of the plasma of Standard Model particles is determined by temperature and exactly conserved combinations of baryon and lepton numbers. We show that at nonzero values of the global charges a translation invariant and ...

American Physical Society2012

Next decade of sterile neutrino studies

Alexey Boyarsky, Oleg Ruchayskiy

We review the status of sterile neutrino dark matter and discuss astrophysical and cosmological bounds on its properties as well as future prospects for its experimental searches. We argue that if sterile neutrinos are the dominant fraction of dark matter, ...

2012

The haloes of bright satellite galaxies in a warm dark matter universe

Alexey Boyarsky, Oleg Ruchayskiy, Jie Wang

High-resolution N-body simulations of galactic cold dark matter haloes indicate that we should expect to find a few satellite galaxies around the Milky Way whose haloes have a maximum circular velocity in excess of 40 km s-1. Yet, with the exception of the ...

Blackwell Publishing Ltd, Oxford2012

A comment on the emission from the Galactic Center as seen by the Fermi telescope

Alexey Boyarsky, Oleg Ruchayskiy

In the recent paper of Hooper and Goodenough (2010) [10] it was reported that gamma-ray emission from the Galactic Center region contains an excess compared to the contributions from the large-scale diffuse emission and known point sources. This excess was ...

2011

Proposed new probe of modified gravity

Alexey Boyarsky, Oleg Ruchayskiy

We suggest a new efficient way to constrain a certain class of large scale modifications of gravity. We show that the scale-free relation between density and size of dark matter halos, predicted within the ACDM model with Newtonian gravity, gets modified i ...

2011

Searching for dark matter in X-rays: how to check the dark matter origin of a spectral feature

Alexey Boyarsky, Oleg Ruchayskiy

A signal from decaying dark matter (DM) can be unambiguously distinguished from spectral features of astrophysical or instrumental origin by studying its spatial distribution. We demonstrate this approach by examining the recent claim of Loewenstein and Ku ...

Blackwell Publishing Ltd, Oxford2010

Anomaly driven signatures of new invisible physics at the Large Hadron Collider

Alexey Boyarsky, Oleg Ruchayskiy

Many extensions of the Standard Model (SM) predict new neutral vector bosons at energies accessible by the Large Hadron Collider (LHC). We study an extension of the SM with new chiral fermions subject to non-trivial anomaly cancellations. If the new fermio ...

2010

Universal Properties of Dark Matter Halos

Igor Tkachev, Alexey Boyarsky, Oleg Ruchayskiy

We discuss the universal relation between density and size of observed dark matter halos that was recently shown to hold on a wide range of scales, from dwarf galaxies to galaxy clusters. Predictions of cold dark matter (Lambda CDM) N-body simulations are ...

2010

EDGE: Explorer of diffuse emission and gamma-ray burst explosions

Mikhail Chapochnikov, Matthias Finger, Alexey Boyarsky, Oleg Ruchayskiy, Simone Campana

How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysical cosmology. EDGE (Piro et al., 2007) will trace the cosmic history of the baryons from the early generations of massive ...

2009

The role of sterile neutrinos in cosmology and astrophysics

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy

We present a comprehensive overview of an extension of the Standard Model that contains three right-handed (sterile) neutrinos with masses below the electroweak scale [the Neutrino Minimal Standard Model (vMSM)]. We consider the history of the Universe fro ...

Annual Reviews2009

Constraining dark matter properties with SPI

Alexey Boyarsky, Oleg Ruchayskiy

Oxford, Blackwell Publishing Ltd2008

Anomaly induced effects in a magnetic field

Alexey Boyarsky, Oleg Ruchayskiy

We consider a modification of electrodynamics by an additional light massive vector field, interacting with the photon via Chern-Simons-like coupling. This theory predicts observable effects for the experiments studying the propagation of light in an exter ...

2008

Constraints on decaying dark matter from XMM-Newton observations of M31

Alexey Boyarsky, Oleg Ruchayskiy

We derive constraints on the parameters of the radiatively decaying dark matter (DM) particle, using the XMM-Newton EPIC spectra of the Andromeda galaxy (M31). Using the observations of the outer (5-13 arcmin) parts of M31, we improve the existing constrai ...

Blackwell Publishing Ltd, Oxford2008

Lyman-alpha constraints on warm and on warm-plus-cold dark matter models

Alexey Boyarsky, Oleg Ruchayskiy, Julien Lesgourgues

We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up which is a good approximation for several theoretically wel ...

2008

How to find a dark matter sterile neutrino?

Mikhail Chapochnikov, Igor Tkachev, Alexey Boyarsky, Oleg Ruchayskiy

We propose a strategy for how to look for dark matter particles possessing a radiative decay channel and derive constraints on their parameters from observations of x rays from our own Galaxy and its dwarf satellites. When applied to sterile neutrinos in t ...

2006

Page 2 sur 3