A5058916629- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Particle Detector Development and Performance
- Business, Innovation, and Economy
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- Seismology and Earthquake Studies
- CCD and CMOS Imaging Sensors
- Astronomy and Astrophysical Research
- Calibration and Measurement Techniques
- Computational Physics and Python Applications
- Precipitation Measurement and Analysis
- Atmospheric Ozone and Climate
- Environmental Monitoring and Data Management
- Cooperative Studies and Economics
University of Amsterdam
2019-2025
San Francisco State University
2023-2025
University of Canterbury
2012-2023
The University of Tokyo
2019-2023
TU Dortmund University
2023
University of Łódź
2023
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2023
University of Turku
2023
Niels Brock
2023
University of Copenhagen
2023
Employing Fermi-LAT gamma-ray observations, several independent groups have found excess extended emission at the Galactic Center (GC). Both annihilating dark matter (DM) or a population of $\ensuremath{\sim}{10}^{3}$ unresolved millisecond pulsars (MSPs) are regarded as well-motivated possible explanations. However, there significant uncertainties in diffuse galactic background GC. We performed revaluation these two models for source GC by accounting systematic model. also marginalize over...
The Fermi-LAT data appear to have an excess of gamma rays from the inner 150 pc Galactic Center. main explanations proposed for this are: unresolved population millisecond pulsars (MSPs), dark matter (DM) annihilation, and nonthermal bremsstrahlung produced by a electrons interacting with neutral gas in molecular clouds. first two options spatial templates well fitted square generalized Navarro-Frenk-White (NFW) profile slope $\gamma=1.2$. We model third option 20-cm continuum emission Ridge...
Axion dark matter (DM) may convert to radio-frequency electromagnetic radiation in the strong magnetic fields around neutron stars. The radio signature of such a process would be an ultra-narrow spectral peak at frequency determined by mass axion particle. We analyze data we collected from Robert C. Byrd Green Bank Telescope L-band and Effelsberg 100-m L-Band S-band number sources expected produce bright signals axion-photon conversion, including Galactic Center Milky Way nearby isolated...
The Fermi Large Area Telescope has observed an excess of ~GeV energy gamma rays from the center Milky Way, which may arise near-thermal dark matter annihilation. Firmly establishing origin for this is however complicated by challenges in modeling diffuse cosmic-ray foregrounds as well unresolved astrophysical sources, such millisecond pulsars. Non-Poissonian Template Fitting (NPTF) one statistical technique that previously been used to show at least some fraction GeV likely due a population...
TeV-scale particles that couple to the standard model through weak force represent a compelling class of dark matter candidates. The search for such Weakly Interacting Massive Particles (WIMPs) has already spanned multiple decades, and whilst it yet provide any definitive evidence their existence, viable parameter space remains. In this paper, we show upcoming Cherenkov Telescope Array (CTA) significant sensitivity uncharted at TeV mass scale. To do so, focus on two prototypical candidates,...
The gamma-ray Fermi-LAT Galactic centre excess (GCE) has puzzled scientists for over 15 years. Despite ongoing debates about its properties, and especially spatial distribution, nature remains elusive. We scrutinize how the estimated morphology of this depends on models diffuse emission, focusing particularly extent to which plane point sources are masked. Our main aim is compare a spherically symmetric - potentially arising from annihilation dark matter (DM) particles with boxy expected if...
The extended excess toward the Galactic Center (GC) in gamma rays inferred from Fermi-LAT observations has been interpreted as being due to dark matter (DM) annihilation. Here, we perform new likelihood analyses of GC and show that, when including templates for stellar galactic nuclear bulges, shows no significant detection a DM annihilation template, even after generous variations diffuse emission models wide range halo profiles. We include with combinations three-dimensional inverse...
We set conservative constraints on decaying dark matter particles with masses spanning a very wide range (104−1016 GeV). For this we use multimessenger observations of cosmic-ray (CR) protons/antiprotons, electrons/positrons, neutrinos/antineutrinos and gamma rays. Focusing decays into the b channel, simulate spectra yields by using Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations Pythia package. then propagate CRs origin till Earth state-of-the-art numerical frameworks CRPropa, GALPROP...
Abstract We present a new reconstruction of the distribution atomic hydrogen in inner Galaxy that is based on explicit radiation transport modeling line and continuum emission gas-flow model barred provides distance resolution for lines sight toward Galactic center. The main benefits gas are (a) ability to reproduce negative signals seen with HI4PI survey (b) accounting primarily manifests itself through absorption. apply an analysis diffuse gamma-ray from Galaxy, which excess at few GeV was...
Fermi Large Area Telescope data reveal an excess of GeV gamma rays from the direction Galactic Center and bulge. Several explanations have been proposed for this including unresolved population millisecond pulsars (MSPs) self-annihilating dark matter. It has claimed that a key discriminant or against MSP explanation can be extracted properties luminosity function describing source population. Specifically, is putative MSPs in consistent with characterizing resolved disk? To investigate we...
Abstract The High-Altitude Water Cherenkov Telescope (HAWC) has detected TeV halos associated with two nearby pulsars/pulsar wind nebulae (PWN) — Geminga and B0656+14. These extend up to tens of pc from the central accelerators, indicating that diffusion ultrarelativistic electrons positrons in interstellar medium been suppressed by orders magnitude. Although B0656+14 are at similar distances same field view, they have distinct histories. Notably, probably still resides within its parent...
The singlet-doublet fermion dark matter model (SDFDM) provides a good DM candidate as well the possibility of generating neutrino masses radiatively. search and identification requires combined effort both indirect direct detection experiments in addition to LHC. Remarkably, an excess GeV gamma rays from Galactic Center (GCE) has been measured with \textit{Fermi} Large Area Telescope (LAT) which appears be robust respect changes diffuse galactic background modeling. Although several...
There is growing evidence that the Galactic Center Excess identified in $\textit{Fermi}$-LAT gamma-ray data arises from a population of faint astrophysical sources. We provide compelling supporting by showing morphology excess traces stellar over-density bulge. By adopting template bulge stars obtained triaxial 3D fit to diffuse near-infrared emission, we show it detected at high significance. The significance deteriorates when either position or orientation artificially shifted, correlation...
The Galactic Center Excess (GCE) is an extended gamma-ray source in the central region of Galaxy found Fermi Large Area Telescope (Fermi-LAT) data. One leading explanations for GCE unresolved population millisecond pulsars (MSPs) bulge. Due to differing star formation histories it expected that MSPs bulge are older and therefore dimmer than those disk. Additionally, correlations between spectral parameters spin-down rate corresponding neutron stars have been observed. This implies may be...
Intriguing signals with excesses over expected backgrounds have been observed in many astrophysical and terrestrial settings, which could potentially a dark matter origin. Astrophysical include the Galactic Center GeV gamma-ray excess detected by Fermi Gamma-Ray Space Telescope, AMS antiproton positron excesses, 511 3.5 keV X-ray lines. Direct detection DAMA/LIBRA annual modulation signal, XENON1T excess, low-threshold solid state detectors. We discuss avenues to resolve these actions field...
Excess GeV gamma rays from the Galactic Center (GC) have been measured with Fermi Large Area Telescope (LAT). The presence of GC excess (GCE) appears to be robust respect changes in diffuse galactic background modeling. three main proposals for GCE are an unresolved population millisecond pulsars (MSPs), outbursts cosmic region, and self-annihilating dark matter (DM). injection secondary electrons positrons into interstellar medium (ISM) by MSPs or DM annihilations can lead observable...
ABSTRACT The abundance and narrow magnitude dispersion of Red Clump (RC) stars make them a popular candidate for mapping the morphology bulge region Milky Way. Using an estimate RC’s intrinsic luminosity function, we extracted three-dimensional density distribution RC from deep photometric catalogues VISTA Variables in Via Lactea (VVV) survey. We used maximum entropy-based deconvolution to extract spatial Ks-band star counts. obtained our extrapolated non-parametric model over inner 40° ×...
Millisecond pulsars are very likely the main source of gamma-ray emission from globular clusters. However, relative contributions two separate processes--curvature radiation millisecond pulsar magnetospheres vs. inverse Compton relativistic pairs launched into cluster environment by pulsars--have long been unclear. To address this, we search for evidence in 8-year $\textit{Fermi}$-LAT data directions 157 Milky Way We find a mildly statistically significant (3.8$σ$) correlation between...
We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data Fermi-LAT weak lensing surveys that cover a wide area $\sim660$ squared degrees in total. improve upon our previous by using an updated extragalactic $\gamma$-ray background reprocessed with Fermi Pass 8 pipeline, well-calibrated shape measurements about twelve million galaxies Canada-France-Hawaii Lensing Survey (CFHTLenS) Red-Cluster-Sequence (RCSLenS)....