English
Related papers

Related papers: Spurious Point Source Signals in the Galactic Cent…

200 papers

The positron fraction in cosmic rays was found to be steadily increasing in function of energy, above $\sim$10 GeV. This behaviour contradicts standard astrophysical mechanisms, in which positrons are secondary particles, produced in the…

High Energy Astrophysical Phenomena · Physics 2015-10-27 Mathieu Boudaud

The GLIMPSE (Galactic Legacy Mid-Plane Survey Extraordinaire) Point Source Catalog of ~ 30 million mid-infrared sources towards the inner Galaxy, 10 < |l| < 65 degrees and |b| < 1 degree, was used to determine the distribution of stars in…

Diffuse TeV emission has been observed by H.E.S.S. in the Galactic Center region, in addition to the GeV gamma rays observed by Fermi. We propose that a population of unresolved millisecond pulsars located around the Galactic Center,…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Claire Guépin , Lucia Rinchiuso , Kumiko Kotera , Emmanuel Moulin , Tanguy Pierog , Joseph Silk

Through high-precision radio timing observations, we show that five recycled pulsars in the direction of the Galactic Centre (GC) have anomalous spin period time derivative ($\dot P$) measurements -- PSRs J1748$-$3009, J1753$-$2819,…

With the Fermi-LAT data quite a few research groups have reported a spatially extended GeV $\gamma$-ray excess surrounding the Galactic Center (GC). The physical origin of such a GeV excess is still unclear and one interesting possibility…

High Energy Physics - Phenomenology · Physics 2016-06-22 Ming-Yang Cui , Cun Zhang , Hong-Shi Zong

We numerically investigate abundance properties of the Galactic globular clusters (GCs) by adopting a new ``external pollution'' scenario. In this framework, GCs are assumed to originate in forming low-mass dwarfs embedded in dark matter…

Astrophysics · Physics 2008-11-26 K. Bekki , S. W. Campbell , J. C. Lattanzio , J. E. Norris

We analyse predictions of the CR lepton fluxes at the Earth of both secondary and primary origins, evaluate the theoretical uncertainties, and determine their level of consistency with respect to the available data. For propagation, we use…

High Energy Astrophysical Phenomena · Physics 2011-01-19 T. Delahaye , J. Lavalle , R. Lineros , F. Donato , N. Fornengo

If the gamma-ray excess from the galactic center reported by Fermi-LAT is a signal from annihilating dark matter, one must question why a similar excess has not been observed in dwarf spheroidal galaxies. We use this observation to place…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-07 Jeremie Choquette

The Milky Way centre exhibits an intense flux in the gamma and X-ray bands, whose origin is partly ascribed to the possible presence of a large population of millisecond pulsars (MSPs) and cataclysmic variables (CVs), respectively. However,…

Astrophysics of Galaxies · Physics 2018-06-13 Manuel Arca-Sedda , Bence Kocsis , Timothy Brandt

We present a catalogue of point-like H{\alpha}-excess sources in the Northern Galactic Plane. Our catalogue is created using a new technique that leverages astrometric and photomeric information from Gaia to select H{\alpha}-bright outliers…

The positron excess measured by PAMELA and AMS can only be explained if there is one or several sources injecting them. Moreover, at the highest energies, it requires the presence of nearby ($\sim$hundreds of parsecs) and middle age…

High Energy Astrophysical Phenomena · Physics 2017-08-11 R. Lopez-Coto , J. Hahn , J. Hinton , R. D. Parsons , F. Salesa Greus , S. BenZvi , M. U. Nisa , H. Zhou

Gamma ray emission of 511 keV lines arising from electron-positron annihilation has been detected from the Galaxy since the 70s. Spatially resolved observations using the INTEGRAL satellite have shown its full sky distribution to be…

High Energy Astrophysical Phenomena · Physics 2014-07-11 Hagai B. Perets

Secondary positrons are produced by spallation of cosmic rays within the interstellar gas. Measurements have been typically expressed in terms of the positron fraction, which exhibits an increase above 10 GeV. Many scenarios have been…

Astrophysics · Physics 2009-10-06 T. Delahaye , F. Donato , N. Fornengo , J. Lavalle , R. Lineros , P. Salati , R. Taillet , .

Using recent measurements of the spectrum and chemical composition of the highest energy cosmic rays, we consider the sources of these particles. We find that the data strongly prefers models in which the sources of the ultra-high energy…

High Energy Astrophysical Phenomena · Physics 2015-09-23 Andrew M. Taylor , Markus Ahlers , Dan Hooper

We aim to investigate the IR excess of 45 MW Cepheids combining different observables to constrain the presence of CSE. We used the SPIPS algorithm, a robust implementation of the parallax-of-pulsation method that combines photometry,…

Solar and Stellar Astrophysics · Physics 2021-07-28 A. Gallenne , A. Mérand , P. Kervella , G. Pietrzyński , W. Gieren , V. Hocdé , L. Breuval , N. Nardetto , E. Lagadec

Galaxy imaging surveys observe a vast number of objects that are affected by the instrument's Point Spread Function (PSF). Weak lensing missions, in particular, aim at measuring the shape of galaxies, and PSF effects represent an important…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 T. Liaudat , J. Bonnin , J. -L. Starck , M. A. Schmitz , A. Guinot , M. Kilbinger , S. D. J. Gwyn

The so-called "GeV-excess" of the diffuse Galactic gamma-ray emission is studied with a spectral template fit based on energy spectra. The spectral templates can be obtained in a data-driven way from the gamma-ray data, which avoids the use…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Wim de Boer , Leo Bosse , Iris Gebauer , Alexander Neumann , Peter Biermann

Measurements of cosmic-ray (CR) positron fraction by PAMELA and other experiments have found an excess above 10 GeV relative to the standard predictions for secondary production in the interstellar medium (ISM). Although the excess has been…

High Energy Astrophysical Phenomena · Physics 2020-06-03 Zhi-Qiu Huang , Ruo-Yu Liu , Jagdish C. Joshi , Xiang-Yu Wang

Primordial non-Gaussianity (PNG) is a signature of fundamental physics in the early universe that is probed by cosmological observations. It is well known that the local type of PNG generates a strong signal in the two-point function of…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 James M. Sullivan , Uros Seljak

An anomalous emission component at energies of a few GeV and located towards the inner Galaxy is present in the Fermi-LAT data. It is known as the Fermi-LAT GeV excess. Using almost 8 years of data we reanalyze the characteristics of this…

High Energy Astrophysical Phenomena · Physics 2018-08-10 Richard Bartels , Emma Storm , Christoph Weniger , Francesca Calore