Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session L12: Dark Matter Searches I: Indirect Searches |
Hide Abstracts |
Sponsoring Units: DAP DPF GPMFC Chair: Brenda Dingus, Los Alamos National Laboratory Room: Plaza Court 2 |
Sunday, May 3, 2009 3:30PM - 3:42PM |
L12.00001: Overview of Dark Matter Searches with Fermi-LAT Simona Murgia The Fermi Large Area Telescope (LAT) has been successfully launched from Cape Canaveral on 11 June 2008. It is exploring the gamma ray sky in the energy range between 20 MeV and 300 GeV with unprecedented sensitivity. One of the most exciting science questions that the Fermi LAT will address is the nature of dark matter. Several theoretical models have been proposed that predict the existence of Weakly Interacting Massive Particles (WIMPs) that are excellent dark matter candidates. The Fermi LAT will investigate the existence of WIMPs primarily through their annihilation or decay into photons and into electrons. I will present an overview of the dark matter search strategy with the LAT and summarize the current status of the searches. [Preview Abstract] |
Sunday, May 3, 2009 3:42PM - 3:54PM |
L12.00002: Preliminary Results for Fermi-LAT Milky Way High Energy Gamma Line Limits Yvonne Edmonds, Elliott Bloom The FGST Large Array Telescope (Fermi-LAT) Collaboration Dark Matter and New Physics Working group has been developing approaches for the indirect astrophysical detection of dark matter by its annihilation or decay products. Our work is motivated by the hypothesis that a significant component of dark matter is Weakly Interacting Massive Particles (WIMPs). The annihilation of two WIMPs or WIMP decay usually results in the production of many $\gamma$ rays that if present, can be well measured in the LAT. There is also the possibility to observe $\gamma$ lines from annihilation or decay into $\gamma \gamma$ and/or $\gamma$Z final states. Detection of these high energy $\gamma$ lines would give convincing evidence for the existence of WIMPs and a measurement of the WIMP mass. We present preliminary work that will ultimately lead to 1-year upper limits on $\gamma$ lines. The 1-year analysis will be a ``blind'' analysis developed on the first two months of Fermi-LAT data and Monte Carlos simulations. Limits will be given independent of the WIMP and dark matter structure models. [Preview Abstract] |
Sunday, May 3, 2009 3:54PM - 4:06PM |
L12.00003: The Search for Dark Matter in the Milky Way Halo with Fermi-LAT Robert Johnson The Fermi Gamma-ray Space Telescope (FGST) successfully launched June 11th, 2008.~ Its improved sensitivity and spectral coverage compared to its predecessor, EGRET, offers the opportunity to search for new physics with photon energies up to about 300 GeV, giving access to a scale where Weakly Interacting Massive Particles (WIMPs) masses have yet to be ruled out. We present a method for the indirect detection of Weakly Interacting Massive Particles (WIMPs) through annihilation into gamma rays in the Milky Way halo, by fitting the FGST data to a combination of models for galactic diffuse emission and dark matter annihilation. We present our current sensitivity for this search, discuss systematic issues, including uncertainties in the diffuse emission model, and explore prospects for the future. [Preview Abstract] |
Sunday, May 3, 2009 4:06PM - 4:18PM |
L12.00004: The Search for Dark Matter Galactic Satellites with Fermi-LAT Ping Wang, Elliott Bloom LCDM model computer simulations predict a large number of as yet unobserved dark matter (DM) galactic satellites (DM-GS) in our galaxy. Our work assumes that a significant component of DM is a Weakly Interacting Massive Particle (WIMP) in the 100 GeV mass range. The annihilation or decay of WIMPs results in many high energy gamma rays that can be well measured by the Fermi Large Area Space Telescope (Fermi-LAT). The WIMP produced spectrum from the putative DM-GS are considerably harder than most astrophysical sources, are not power laws, there are no counterparts, and the emission has no time variability. This talk will focus on the blind analysis we plan to perform on about 1 year of Fermi-LAT data in our search for DM-GS, which has been developed using the first 2 months of Fermi-LAT data and Monte Carlo simulations. Preliminary limits from this analysis using the first 2 months of Fermi-LAT data will be also discussed. [Preview Abstract] |
Sunday, May 3, 2009 4:18PM - 4:30PM |
L12.00005: Search for the Gamma-Ray Signature of Dark Matter with VERITAS Matthew Wood A leading candidate for astrophysical dark matter (DM) is a massive particle with a mass in the range from 50 GeV to greater than 10 TeV and an interaction cross section on the weak scale. The self-annihilation of such particles in astrophysical regions of high DM density can generate stable secondary particles including VHE gamma rays with energies up to the DM particle mass. Dwarf spheroidal galaxies of the Local Group are attractive targets to search for the annihilation signature of DM due to their proximity and large DM content. We report on gamma-ray observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) of several dwarf galaxy targets. We discuss the implications of these measurements for the parameter space of DM particle models. [Preview Abstract] |
Sunday, May 3, 2009 4:30PM - 4:42PM |
L12.00006: ABSTRACT WITHDRAWN |
Sunday, May 3, 2009 4:42PM - 4:54PM |
L12.00007: Study of indirect detection of Axion-Like-Particles with the~Fermi-LAT instrument and Imaging Atmospheric Cherenkov Telescopes David Paneque, Elliott Bloom, Miguel Sanchez-Conde Axion like Particles (ALPs) are predicted to couple with photons in the presence of magnetic~fields.~~This effect may lead to a significant change in the observed spectra of VHE sources such as AGNs. We performed a study that considers both the photon/axion mixing that takes place in the gamma-ray source and~the mixing expected to occur~via~the intergalactic magnetic fields between the source and the Earth. An efficient photon/axion mixing in the source always means attenuation in the photon flux, whereas the mixing in the intergalactic medium may result in a decrement and/or enhancement of the photon flux, depending on the distance of the source and the energy considered.~We also~predict~an attenuation in the intensity spectrum of distant sources, which occurs at an energy that only depends on the properties of the ALPs and the intensity of the intergalactic magnetic field, and thus is independent of the AGN source being observed.~In the presentation we will~provide a prescription for the indirect detection of ALPs with gamma-ray instruments and will present preliminary results derived from AGN spectra using published IACT and Fermi-LAT data. [Preview Abstract] |
Sunday, May 3, 2009 4:54PM - 5:06PM |
L12.00008: Shedding Light on Dark Matter: A Faraday Rotation Experiment to Limit a Dark Magnetic Moment Susan Gardner I describe a new possibility for the direct detection of dark matter. That is, if dark matter consists, in part, of cold, neutral particles with a non-zero magnetic moment, then, in the presence of an external magnetic field, a measurable gyromagnetic Faraday effect becomes possible. A Faraday rotation experiment can set limits on the magnetic moment of a electrically-neutral, dark-matter particle, and the limits increase in stringency as the candidate mass decreases. I describe how such could be realized and determine the limits on the magnetic moment as a function of mass which follow given demonstrated experimental capacities. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700