NPAC (Nuclear/Particle/Astro/Cosmo) Forum

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has continuously observed the gamma-ray sky since June 2008.
Cosmic-ray protons represent the majority of events downloaded from the Fermi-LAT, which are removed from the gamma-ray dataset. Our sample is comprised of over 1 billion cosmic-ray protons to TeV energies. We present the measurement of the cosmic-ray proton spectrum between 54 GeV and 9.5 TeV using 7 years of Pass 8 flight data from the Fermi-LAT. We developed a dedicated proton event selection with an acceptance of 0.25 m^2 sr. Our analysis yields a large dataset with low statistical uncertainty and low residual contamination for a spectral measurement. The systematic errors associated with the acceptance, energy measurement, GEANT4 Monte-Carlo simulations are an order of magnitude larger than the statistical uncertainty. The event selection and spectral measurement of the proton analysis create the opportunity for additional proton analyses with the Fermi-LAT, such as a dedicated proton anisotropy search.
Host: 
Stefan Westerhoff
Speaker: David Green University of Maryland/Goddard

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall

The detection of astrophysical neutrinos with IceCube and solid predictions of the flux of cosmogenic neutrinos have renewed the interest in detecting neutrinos at 10^9 GeV. To date no experiment exists with sufficient sensitivity at these energies and thus the motivation for this study. I take a fresh look at the Earth-skimming technique in which a tau neutrino converts in the Earth's mantle and the decay products of the tau are detected with Cherenkov telescopes that monitor a large volume of atmosphere. In this talk I present a conceptual design study of an array of Cherenkov telescopes that is optimized for 10^9 GeV and has a sensitivity that is competitive with other proposed experiments.

Host: 
Justin Vandenbroucke
Speaker: Nepomuk Otte Georgia Tech

 

Available Downloads:

Room and Building: 
4274 Chamberlin Hall

Crucial questions about solar neutrinos remain unanswered. Our knowledge of stellar fusion processes and neutrinos themselves is incomplete. Neutrino detectors such as Super-Kamiokande have the exposure needed, but backgrounds are limiting. A leading background is the beta decays of isotopes produced by cosmic-ray muons and their secondary particles, which initiate nuclear spallation reactions. I will discuss my comprehensive studies of the spallation backgrounds, from calculating their production rates, to understanding their production mechanisms, to how to implement better background rejection methods. I will also discuss the applications of our MeV work in detecting PeV astrophysical neutrinos in IceCube.

Host: 
Stefan Westerhoff
Speaker: Shirley Li Ohio State University

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall
Cosmic rays, high energy particles originating from outside of the solar system, are believed to be dominated by particles from our Galaxy at least up to the energy of 10^15 eV. Recent results from direct measurements of cosmic rays, including the rise of the positron flux, the hardening of the light nuclei, and the different spectral indexes of the proton and helium spectra, challenge the classical models of the Galactic cosmic rays. Meanwhile, the development of gamma-ray experiments has opened a new window to study the acceleration and propagation of high-energy particles in the vicinity of the source sites, such as supernova remnants.

I will present the Galactic gamma-ray measurements from the VERITAS experiment, an imaging atmospheric Cherenkov telescope measuring gamma rays with energies higher than 85 GeV and up to ~ 30 TeV. Focusing on the supernova remnants, I will discuss what we have learned about the acceleration of high-energy particles with gamma-ray observations. I will also introduce the near-future balloon-borne experiment, HELIX (High Energy Light Isotope eXperiment), which is designed to measure the clock isotope 10^Be up to 10 GeV/n to study the propagation of Galactic cosmic rays. Finally, I will highlight how measurements from different disciplines, such as cosmic-ray and gamma-ray astrophysics, will broaden our perspectives on high-energy particles and advance us towards a new paradigm of Galactic cosmic rays.
Host: 
Stefan Westerhoff
Speaker: Nahee Park University of Chicago

 

Available Downloads:

Room and Building: 
5280 Chamberlin hall
The continuing study of the gamma-ray sky has revealed a large population of extreme astrophysical accelerators capable of emitting electromagnetic radiation up to the highest observable energies, in the TeV range. Above 100 GeV, gamma-ray observations can be performed from the ground using large optical telescopes sensitive to the Cherenkov radiation emitted by gamma-ray air showers. The VERITAS observatory, an array of four Cherenkov telescopes located in Southern Arizona, uses this technique to study Galactic and extragalactic sources, probe cosmological radiation fields, and search for evidence of dark matter, among other science projects. In this talk, I will summarize recent results from the VERITAS observatory and describe synergies with other observatories currently in operation. I will briefly describe the Cherenkov Telescope Array (CTA), the next-generation TeV gamma-ray instrument, that will provide an order-of magnitude improvement in sensitivity over current instruments such as VERITAS and the status of the US contribution to this project.
Host: 
Vandenbroucke
Speaker: Marcos Santander Barnard College - Columbia University

 

Available Downloads:

Room and Building: 
4274 Chamberlin Hall

I will report a characterization of the NUV Silicon Photomultipliers (SiPMs) developed by Fondazione Bruno Kessler and tested at INFN in Bari (Italy). A dedicated setup has been built in order to measure crucial parameters such as gain, correlated noise and signal – to –noise ratio. The devices tested are SiPMs of different cell size and areas in single or matrix configuration. In particular, I will present last results concerning laboratory tests on the new NUV High Density SiPMs, which are characterised by an increased fill factor respect to the NUV devices.

Host: 
Justin Vandenbroucke
Speaker: Daniela Simone INFN Bari

 

Available Downloads:

Room and Building: 
5310 Chamberlin hall
I'll give a brief overview of Gamma-Ray Bursts (GRBs) observations performed over the past 8 years by the two instruments on-board the Fermi satellite, namely the Gamma-Ray Burst Monitor (GBM) and the Large Area Telescope (LAT).<br><br>
In this period of time, GBM has triggered and located on average approximately two GRBs every three days. The most recent results are summarized in the latest two catalogs provided by the Fermi GBM science team, namely the third GBM GRB catalog and the first GBM time-resolved spectral catalog.<br><br>
Moreover, the Fermi LAT science team has been recently performing an extensive search for GRBs at high energies (>100 MeV) featuring a detection efficiency more than 50% better than previous works, and returning more than 130 detections.<br><br>
Finally, I'll present the GBM and LAT follow-up of the LIGO Gravitational Wave event GW 150914, focusing on the GBM detection of a weak transient event, close in time to the LIGO one. Future joint observations of GW events by LIGO/Virgo and Fermi could reveal whether the weak transient reported by GBM is a plausible counterpart to GW150914 or a chance coincidence, and will further probe the connection between compact binary mergers and short GRBs.
Host: 
Justin Vandenbroucke
Speaker: Elisabetta Bissaldi Politecnico & INFN Bari

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall
Title: A novel on-chip, mm-wavelength spectrometer for mapping the high-redshift universe.

SuperSpec is an compact on-chip spectrometer for mm and submm wavelength astronomy. Its small size, wide spectral bandwidth, and highly multiplexed detector readout will enable construction of powerful multi-object spectrometers for high-redshift observations. The design employs a filter bank consisting of a series of superconducting thin film circuit elements, each coupled to titanium nitride lumped-element kinetic inductance detector (KID.) I will discuss the design, optimization, and measured performance of our prototype devices, our upcoming observing run with the SuperSpec demonstration camera, and the observations that will become possible with a large multi-object-spectrometer based upon this technology. These future instruments will allow us to characterize thousands of high redshift dusty star forming galaxies and to measure to characterize star formation during the epoch of reionization through tomographic intensity mapping.
Host: 
Peter Timbie
Speaker: Erik Shirokoff University of Chicago

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall
AMS-02 is a cosmic ray detector operating on the International Space Station since May 2011.
The main goals of the AMS mission are the detection of primordial antimatter and indirect Dark Matter signatures in the fluxes of cosmic rays through the accurate measurement of their composition and energy spectra up to the TeV scale.
The most recent AMS results and the consequent potential advances in the current understanding of cosmic ray origin, acceleration and propagation physics will be reviewed.
Host: 
Vandenbroucke
Speaker: Valerio Vagelli University of Perugia

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall
The recent discovery of high-energy astrophysical neutrinos has opened a new window to the Universe. However, the sources of those neutrinos are still unknown. Among the plausible candidates are active galactic nuclei, gamma-ray bursts and supernovae. Combining neutrino data with electromagnetic measurements in a multi-messenger approach will increase the sensitivity to identify the neutrino sources and help to solve long-standing problems in astrophysics such as the origin of cosmic rays.

I will review the recent progress in multi-messenger astronomy using neutrino data.
Host: 
Albrecht Karle
Speaker: Anna Franckowiak DESY, Germany

 

Available Downloads:

Room and Building: 
5280 Chamberlin Hall (coffee)

Pages

©2013 Board of Regents of the University of Wisconsin System