Fermi Cycle-2 Guest Investigations
Proposal ID Principal Investigator Title Abstract
(Large Project)
P. SMITH THE GAMMA-RAY / OPTICAL CONNECTION IN BLAZARS DURING THE FERMI ERA We propose to continue monitoring the optical polarization and flux spectra of blazars followed by Fermi. Analysis of the data will focus on correlating the optical polarization, which provides direct information on the magnetic field within the continuum source, with the gamma-ray variability. The program has been highly successful during Cycle 1 and data obtained during its first 40 nights for the LAT-monitored blazars are available at http://james.as.arizona.edu/~psmith/Fermi. The initial target list will be modified using the LAT bright source catalog to include more blazars suitable for variability studies on daily time scales. As in Cycle 1, optical data will be obtained during 10, week-long campaigns distributed throughout each year and will be made public as rapidly as possible.
(Large Project)
T. PORTER MULTI-WAVELENGTH STUDY OF THE DIFFUSE EMISSION FROM COSMIC-RAY PROPAGATION IN THE MAGELLANIC CLOUDS AND M31 The diffuse emissions from radio to high-energy gamma rays (> 100 MeV) arising from various interactions between cosmic rays and the ISM, interstellar radiation field, and magnetic field are currently the best way to characterize cosmic ray physics in other galaxies. We propose to combine Fermi data with existing far-infrared and radio continuum imagery for the Magellanic Clouds and M31, and compare with the results of modeling the broadband diffuse emission from these galaxies with the well-known GALPROP code. This will be the first time such a multi-wavelength study combining analysis of the broadband data with detailed models has been possible, and will lead to critical new constraints on cosmic-ray propagation and origins in these nearby galaxies.
(Large Project)
B. DENNIS FERMI SOLAR FLARE OBSERVATIONS We propose a 3-year effort to ensure realization of the unique scientific potential of Fermi solar-flare observations. We will make the GBM and LAT flare data and our IDL analysis tools readily accessible to the solar community. We will analyze X- and gamma-ray flares, and cross-calibrate GBM with RHESSI and other solar instruments. From these measurements we will obtain information on flare-accelerated electrons and ions that can be compared with SEPs. We will expand the pion-decay model used in LAT analysis to include non-isotropic production. We propose autonomous solar pointing to optimize the study of long-duration gamma-ray flares with LAT. We will en-courage the international solar physics community to carry out joint scientific analysis of Fermi data.
21009 J. ORMES AN EARTH CENTERED MAPPING OF THE RESIDUAL BACKGROUND IN THE FERMI LAT The most sensitive observations using the Fermi LAT, such as measurement of extragalactic diffuse gamma radiation, depend on detailed analysis of the local haze of "irreducible" background, photons generated by galactic cosmic rays and Earth albedo particles outside the active parts of the instrument. The processes to be considered include, but are not limited to, interactions of hadronic cosmic rays, annihilation of positrons, and bremsstrahlung from electrons and positrons. This proposal is to construct maps of the residual background as a function of geographic coordinates and determine whether or not windows through this locally generated background haze can be found and exploited. The method will be applied to a study of the high galactic latitude photons.
21018 M. BOETTCHER VHE GAMMA-RAY INDUCED CASCADES IN QUASAR AND RADIO GALAXY ENVIRONMENTS The recent detections of the low- and intermediate-frequency-peaked BL Lac objects and the quasar 3C279 in very-high-energy (VHE) gamma-rays raised the question of internal gamma-gamma absorption of VHE gamma-rays by the infrared-optical-UV radiation from the central engine (accretion disk, BLR, dust torus). Such absorption would be followed by inverse Compton supported electromagnetic cascades. Here, we propose to investigate the spectral features and angle-dependence of the resulting radiation from the cascade. This may lead to observable features in the Fermi energy range of blazars, and potentially observable GeV excesses in FR II radio galaxies, if they can be interpreted as misaligned gamma-ray quasars.
21023 K. HURLEY ADDING THE FERMI GBM TO THE 3RD INTERPLANETARY NETWORK We propose to integrate the Fermi Burst Monitor (GBM) into the 3rd Interplanetary Network (IPN) of Gamma-Ray Burst (GRB) detectors. This will 1) assist the Fermi team in understanding and reducing their systematic localization uncertainties, 2) reduce the sizes of the GBM error circles by 1-4 orders of magnitude, 3) facilitate the identification of GRB sources with objects found by ground- and space-based observatories at other wavelengths, from the radio to very high energy (VHE) gamma-rays, 4) reduce the uncertainties in associating some LAT detections of high energy photons with GBM bursts, and 5) facilitate searches for non-electromagnetic GRB counterparts, particularly neutrinos and gravitational radiation. We will make our results public as soon as they are available.
21033 B. FIELDS GAMMA RAYS FROM STAR-FORMING GALAXIES Star formation produces supernovae and thus cosmic rays, whose propagation in the interstellar medium creates gamma rays. Cosmic star formation thus produces an unresolved gamma-ray flux which possibly dominates the Fermi diffuse extragalactic background. Our comprehensive study will calculate the expected star-forming signal, identify its observational signature(s), and quantify its uncertainties. The Fermi spectrum for the Galaxy will provide a crucial input. We will for the first time calculate the gamma-ray luminosity function for star-forming galaxies. We will show the impact of direct measurements of the cosmic supernova rate from optical sky surveys. Our results will allow Fermi to probe cosmic-ray origins, cosmic star formation, and the primordial lithium problem.
21034 A. MARKOWITZ QUANTIFYING THE GEV VARIABILITY OF BLAZARS WITH FERMI-LAT We propose to explore the nature of GeV variability in 13 bright blazars using LAT monitoring data. We will compare GeV variability properties of blazars to X-ray variability properties of both blazars and Seyferts, enabling us to explore links between blazars and Seyferts in terms of variability characteristics and to probe disk--jet connections and the nature of the variability mechanism. This analysis will include measuring the GeV power spectra of well-known AGN and measuring fractional variability amplitudes as a function of time and flux level.
21035 B. ZHANG UNVEILING GAMMA-RAY BURST PROMPT EMISSION WITH FERMI DATA We propose to model the broadband prompt emission data of the GRBs that are co-detected by Fermi LAT and GBM. Using both analytical and numerical methods, we will derive useful constraints on the unknown parameters of the GRB ejecta, directly address the three outstanding problems related to GRB prompt emission, i.e. the composition (baryonic vs. Poynting flux dominated), the emission location (photosphere, internal shock, or large radius for magnetic dissipation), and the radiation mechanism (synchrotron, SSC, and Comptonization of thermal photons).
21041 M. BOETTCHER LEPTONIC AND HADRONIC JET MODELS OF BLAZARS We propose a comprehensive effort of comparative leptonic and hadronic modeling of spectral energy distributions and variability of Fermi-LAT monitored blazars. We have, over the past ~15 years, developed state-of-the-art numerical codes for both leptonic and hadronic blazar jet models. In the proposed project, we intend to develop observable diagnostics of different jet matter contents, launching mechanisms, and signatures of various plausible internal and external shock and/or shear flow acceleration mechanisms. Specific model developments will include a detailed time-dependence of hadronic jet models, as well as a realistic treatment of various particle acceleration modes in both time-dependent leptonic and hadronic models.
21044 F. STECKER FERMI BLAZARS AND THE INTERGALACTIC BACKGROUND LIGHT We propose to update our calculations of the IR-UV intergalactic background light (IBL) and the optical depth of the universe to gamma-rays as a function of energy and redshift.. Then, in conjunction with multiwavelenth observations of blazars (including Fermi observations) as inputs to theoretical modeling of possible intrinsic absorption in bright blazars, we will pursue methods for separating intrinsic and extragalactic absorption features in blazar spectra and compare them with templates based on Fermi observations of blazars. This program should lead to empirically based determinations of the IBL as a function of redshift. These in turn can supplement deep astronomical surveys to determine past galaxy evolution.
21046 J. SCARGLE TIME SERIES ANALYSIS ALGORITHMS FOR LAT DATA We will develop data analysis methods to study source variability utilizing LAT's large effective area and sky coverage. We will verify, document and make publically available algorithms addressing luminosity variability from both unbinned or binned data. Algorithms will implement light-curve representations allowing for exposure variation, data gaps, weighting by photon energy and position in PSF, but without fixed resolution limits. Fourier and wavelet methods meant to elucidate scale dependence, energy-dependent time-delays, and multiple light curve comparisons (with amplitude and phase cross-spectra, based on Fourier and wavelet transforms). Correlative analysis of LAT data with OVRO radio frequency monitoring of 1000+ galaxies may yield important model constraints.
21047 R. ROMANI PULSAR GEOMETRY AND THE FOUNDATIONS FOR HIGH-ENERGY MODELS We propose a program of beaming model and population computations to help interpret the menagerie of new LAT pulsar detections. The project seeks to explain the distribution of pulse shapes, the numbers and luminosities of `Geminga's, the detectability of the millisecond pulsars and the pulsar contribution to the diffuse background. Guided by the new LAT data, we propose to study how the gamma-ray beam shuts off as pulsars age and how the radiating pair-formation fronts shifts through the magnetosphere as the pulsar spins down. Results will be published as correlations between observables and population predictions for several leading magnetosphere models.
21050 T. WEEKES MEASUREMENT OF THE SPECTRA OF TEV GAMMA-RAYS FROM MRK 421 AND MRK 501 USING THE WHIPPLE 10M TELESCOPE The two brightest Northern Hemisphere TeV active galactic nuclei (AGN), Mrk 421 and Mrk 501, will be routinely monitored with the Whipple 10m TeV telescope on all nights in which they are visible at the Whipple Observatory, giving both an extended baseline of TeV observations (not practical with VERITAS, HESS and MAGIC) and an early trigger for coordinated multi-wavelength campaigns in the event of flaring activity. The gamma-ray fluxes will be correlated with the GeV results from Fermi on a weekly time-scale to give energy spectra as a function of time and intensity over a six-month time interval. Observations with the optical and infrared telescopes will supplement the gamma-ray observations and permit the time variations in the spectral energy distribution (SED) to be monitored.
21053 S. JORSTAD CORRELATION BETWEEN GAMMA-RAY VARIATIONS AND DISTURBANCES IN THE JETS OF BLAZARS We propose to perform two 2-week campaigns (in October 2009 and in April 2010) of multiwaveband polarization and photometric observations, each of 10 gamma-ray bright blazars. The campaigns will involve, for all sources, (1) daily optical photometric B,V,R, and I measurements, (2) R-band polarimetric observations, and (3) VLBA total and polarized intensity imaging at 43 GHz 3 times per campaign. In addition, we will observe some of the proposed sources at infrared J,H, and K bands, in X-rays, and at TeV band. These will be analyzed along with gamma-ray light curves provided by FSSC to study correlations and time delays among the wavebands in order to establish the origin of the gamma-ray emission and the changing physical conditions in the jets of blazars.
21056 M. ALLER LINEAR POLARIZATION AS A PROBE OF THE PHYSICS OF GAMMA-RAY FLARING BLAZAR JETS We propose to carry out a UMRAO program of multifrequency, centimeter-band, linear polarization and total flux density monitoring of gamma-ray flaring AGN aimed at identifying properties in the radio jet associated with the generation of gamma rays. In combination with VLBA images and radiative transfer calculations, this unique data set will be used to identify changes in the magnetic field direction associated with gamma-ray flaring, and to robustly test whether gamma-ray flaring is associated with the onset of shocks, a plausible particle acceleration mechanism. Detailed study of specific events will yield information on Doppler boosting, bulk Lorentz factor, and particle energetics, key input parameters in models for generating gamma-ray emission.
21059 D. WILLIAMS MULTIWAVELENGTH STUDIES OF TEV CANDIDATES SELECTED FROM LOW REDSHIFT, HARD SPECTRUM FERMI BLAZARS We propose multiwavelength studies of LAT-detected blazars which are promising VHE sources. We select candidates initially from the Bright Source List and will refine the selections when the first year catalog and LAT photon data are released so that the spectra can be studied in detail. We identify AGN where observations with VERITAS, in combination with the Fermi results, will give constraints on the intrinsic SED of the blazar, the amount of extragalactic background light, or both. We will organize VERITAS and other wavelength observations for the most promising candidates and analyze these together with the Fermi data from the same epoch. This work will allow more detailed information to be extracted about the behavior of the studied AGN than can be obtained from the Fermi data alone.
21069 M. MCCONNELL ALBEDO POLARIMETRY OF GAMMA-RAY BURSTS AND SOLAR FLARES WITH GBM Several key properties of GRBs remain poorly understood and are difficult to infer with the information currently being collected. High-energy polarization measurements can probe the precise nature of the central engine. For solar flares, polarization measurements are expected to be useful in determining the beaming of solar flare electrons, a quantity that may provide important clues about electron acceleration and transport. We propose to investigate the viability of using GBM to measure the polarization of GRBs and solar flares using the albedo photon flux. This approach was previously developed for use with BATSE data. We will conduct a careful study of this technique using a modified version of the GRESS simulation tools developed by the GBM team and apply it to selected GBM events.
21071 M. MCCONNELL ALBEDO RADIATION DATA FROM CGRO/COMPTEL AS INPUT TO THE FERMI BACKGROUND MODEL A complete understanding of the instrumental background of the Fermi LAT relies on a thorough knowledge of the in-orbit radiation environment, including the neutral albedo radiations (gammas and neutrons). An important source of data on neutral atmospheric albedo radiations is the CGRO/COMPTEL experiment that orbited the Earth from 1991 to 2000. COMPTEL was designed primarily to study 1-30 MeV gamma-rays, but with a unique capability for studying 10-250 MeV neutrons. A substantial volume of neutral albedo data was collected by COMPTEL. Unfortunately, this unique data set has so far been largely unstudied. We are proposing an effort to analyze these data and to use the results from that analysis as a set of constraints for improving the fidelity of the Fermi low energy background model.
21077 E. HALLMAN PREDICTING THE GAMMA-RAY SIGNATURE OF COSMIC RAY PROTONS IN GALAXY CLUSTERS USING NUMERICAL COSMOLOGICAL SIMULATIONS We propose to predict the gamma ray signature of cosmic ray (CR) proton decay in galaxy clusters using numerical hydro/N-body simulations. Using the adaptive mesh cosmological code Enzo and a novel shock finding method, we will generate a non-thermal relativistic particle distribution in our simulated clusters. The particles are generated through Fermi acceleration at shocks and by AGN in the cluster core. Gamma ray observations with Fermi should provide a strong constraint on the amount of relativistic protons in galaxy clusters, which provides constraints on the amount of non-thermal pressure support in the intracluster medium. Additional pressure terms in the ICM can impact the interpretation of ICM physics from radio and X-ray observations of clusters.
21078 G. TAYLOR THE PARSEC-SCALE CHARACTERISTICS OF FERMI AGN Comparative studies of AGN observed with Fermi and VLBI will yield insights as to where gamma-rays are produced, and how jets are launched and collimated. In anticipation of the Fermi mission we carried out the VLBI Imaging and Polarimetry Survey (VIPS) of 1127 AGN. Besides flat-spectrum radio quasars and BL Lacs, Fermi has already detected two radio galaxies, and could well find gamma-ray emission from Seyferts and Compact Symmetric Objects. Here we propose to study a complete sample of ~200 AGN from the first year Fermi catalog with both VLBI and Fermi measurements. We further request VLBA observations at 5 GHz of these 200 gamma-ray bright AGN in order to obtain estimates of the Lorentz factors of the jets, as well as quasi-simultaneous VLBI measurements.
21080 M. BARING PROMPT EMISSION CONSTRAINTS ON SHOCK ACCELERATION IN GAMMA-RAY BURSTS The Fermi Era has ushered in a new diagnostic capability for the Gamma-Ray Burst paradigm, precipitated by its ability to span the nu-Fnu peak in bright bursts. This proposal exploits such a capability in the spectral fitting of GBM and GBM-LAT bursts, using physical models for several emission processes that are based on particle distributions from diffusive shock acceleration theory. The program will develop compact emission spectral functions for thermal plus non-thermal electrons; these will be folded through the instrument response functions for select bright bursts to ascertain key electron population parameters. These constraints on the GRB internal shock environment will provide core probes of the shock speed, magnetic field obliquity and hydromagnetic turbulence levels.
21087 Y. KOVALEV FOLLOW-UP STUDY OF THE BRIGHTEST GAMMA-RAY FLARES IN FERMI BLAZARS We propose to study the parsec-scale jets in blazars by following up the brightest gamma-ray flares detected within Cycle 2 of the Fermi/LAT mission. We plan to trigger simultaneous multi-wavelength observations with the following key instruments: VLBA (160 hours requested through this Fermi-NRAO joint proposal), Swift (time pre-approved by the Swift project), and Fermi/LAT (standard survey mode). Our project will explore connection between gamma-ray flares and variability of key observational and physical parameters of the sub-parsec-scale jet plasma. We will test whether VLBI core and/or other jet features are capable of producing the extreme gamma-ray flare and if so, constrain the SED models.
21096 P. RAY GAMMA-RAY PULSAR TIMING WITH FERMI We propose a program of precise pulsar timing of radio-quiet (or radio faint) pulsars detected by the Fermi LAT, primarily the newly discovered gamma-ray pulsars found in blind searches of Fermi data. In addition we will time the radio quiet pulsar Geminga, and other radio faint pulsars, such as the one in 3C58, if they are detected by Fermi. Pulsar timing will yield the rotational parameters and arcsecond position determinations, and allow us to study the glitch and timing noise behavior of these sources. These measurements will be critical for multiwavelength followup of these sources and provide parameters critical to the astrophysics of the sources. We will develop the software needed to do pulsar timing using Fermi data and make it available to the community.
21097 P. RAY SEARCH FOR RADIO PULSATIONS FROM GAMMA-RAY PULSARS DISCOVERED WITH FERMI We propose to make sensitive searches using the NRAO Green Bank Telescope (GBT) for radio pulsations from 4 of the 15 pulsars discovered by the Fermi Gamma-ray Space Telescope in blind periodicity searches directly in the gamma-ray data as well as 4 additional pulsars that are likely to be discovered in continued searches. Our searches will reach a luminosity limit below the lowest radio luminosity known for a young radio pulsar and either detect radio pulsations or conclusively establish that these new pulsars are radio quiet. We have chosen the 4 sources that don't already have stringent radio limits and complement other searches proposed at Arecibo.
21105 C. GWINN SEARCH FOR GAMMA-RAY/RADIO CORRELATION OF VELA PULSAR EMISSION We propose to seek correlation of gamma-ray and radio components of the pulses of the Vela pulsar, using existing gamma-ray and radio data. Detection of such correlations would offer insights into the geometry and physical processes of pulsar emission at gamma-ray and radio energies. We previously found evidence for such correlations for X-ray and radio pulses in the Vela pulsar using RXTE, with 99.8% confidence; others have observed similar correlations optical/radio or X-ray/radio correlations for other pulsars. Theoretical pictures suggest such correlations; observations of them, and their range in gamma-ray energy and pulse phase, would offer insight into pulsar emission mechanisms.
21112 C. DERMER MODELING FERMI GAMMA-RAY BLAZARS We propose to apply our spectral modeling capabilities to blazar data obtained with multiwavelength campaigns involving the Fermi Gamma Ray Space Telescope. For synchrotron and self-Compton models, the measured variability time scale defining the size scale gives the best-fit values for Doppler factor and mean magnetic field. For models with external Compton processes, our approach accurately calculates Compton scattering in the Thomson and Klein-Nishina regimes, and consistently accounts for attenuation by the external photons from the accretion disk and broad line region. Fermi data will be used to test the simplest models for these sources, give minimum Doppler factors and absolute jet powers, with implications for unification and evolution of blazars and radio galaxies.
21113 B. DINGUS OLD VS NEW: GEV TO TEV OBSERVATIONS OF THE GEMINGA AND BOOMERANG PULSAR WIND NEBULA Geminga and Boomerang are nearby pulsars that emit GeV pulsations and extended regions of ~ 3 degree diameter (10-40 parsecs) in the TeV observations of Milagro. The large angular extent of these 2 sources and their location away from the strong diffuse emission near the Galactic center make them ideal candidates for studying the unpulsed GeV component. Geminga exhibits a bright off pulse GeV emission. Geminga is one of the oldest pulsars (excluding msec pulsars) that the LAT observes and Boomerang is a relatively young pulsar. We propose to compare the spatial morphology of the Milagro and unpulsed LAT data. Differences in the spatial distributions at GeV and TeV energies will probe the energy loss mechanisms of the electrons in these sources.
21114 F. KRENNRICH SEARCH FOR UNIQUE SIGNATURES FROM EBL ABSORPTION IN UNUSUALLY HARD BLAZAR SPECTRA We propose to use Fermi GeV spectra/upper limits and VERITAS TeV spectra of the unusually hard spectrum TeV blazars 1ES1218+30.4, 1ES0229+200 and RGB J0710+591 to derive constraints on the near/mid-IR ratio of the EBL with the potential of identifying a break at 1 TeV and thus provide the first unambiguous evidence for gamma-ray absorption by the EBL.
21131 M. BARING INTERPRETING THE MAXIMUM EMISSION ENERGIES OF FERMI GAMMA-RAY PULSARS The Fermi gamma-ray pulsar database is rapidly growing, and it already defines an important part of Fermi's early legacy. This project aims to interpret these turnovers via an exploration of core attenuation and emission characteristics as functions of colatitude and altitude in pulsar magnetospheres. The turnover energies provide lower bounds to the mean emission altitude, using arguments of single-photon pair creation transparency - this project will refine such analyses by extending them to moderate altitudes appropriate for slot-gap scenarios. Moreover, it will use the observed turnovers to provide altitudinal constraints for curvature radiation slot-gap or outer gap models. A central goal will be to explore population trends and observability with period and period derivative.
21145 D. HARTMANN NUCLEONIC RESONANCE LINES IN FERMI/LAT GRB SPECTRA We propose to use spectroscopy in the 20 MeV to 200 GeV band to search for nucleonic absorption features in GRBs. If detectable, these lines are the only presently known features that would allow reliable and prompt measurements of gamma-ray burst redshifts from the high energy data directly, and for z > 10. Nucleonic absorption is the underlying tool of the proposed GRIPS mission, and Fermi offers the opportunity to establish nucleonic absorption-line spectroscopy as a viable method. To firmly establish the method we require the more frequent intermediate-z GRBs to asses the presence of these lines.In addition to being a pathfinder for future experiments, Fermi/LAT may also reveal GRBs otherwise hidden by extreme column densities.
21148 M. MALKOV IN SEARCH OF ONGOING COSMIC RAY ACCELERATION IN SUPERNOVA REMNANT SHOCKS Supernova remnant (SNR) shocks are thought to be responsible for the production of galactic cosmic rays (CRs). Cosmic rays drive various instabilities in the shock precursor and create an ensemble of discontinuities, namely a shocktrain. Their magnetic patterns change the transport regime of accelerated particles from diffusive at lower momenta to fractionally kinetic at higher momenta. As a result, a spectral break forms, typically at sub-TeV energies. We propose to study the spectral break phenomena theoretically, in order to predict what spectral signatures of gamma radiation can develop from them. The results of this study will guide our search for signatures of the ongoing cosmic ray acceleration in the gamma-ray Fermi data of major SNRs, such as RXJ 1713.7-3946.
21153 H. KRAWCZYNSKI REVISITING THE BLAZAR SEQUENCE BASED ON CONTEMPORANEOUS SWIFT AND FERMI BLAZAR OBSERVATIONS During the Fermi GO cycle #1, one of us (A. Falcone) received support for organizing regular Swift observations of 26 blazars. The program has been highly successful. In this proposal, we request support for analyzing contemporaneous Fermi data and combining them with the Swift data and with additional data sets. We will fit the broadband Spectral Energy Distributions (SEDs) with parametric models, and derive model parameters for synchrotron-Compton models. The results will be used to revisit the blazar sequence. The excellent sensitivity of Fermi will allow us to see how sources move along evolutionary tracks in various correlation diagrams as they go into different states. For a few selected sources, we will perform more detailed modeling with a time dependent synchrotron-Compton code.
21163 D. PANEQUE OBSERVATIONS WITH MAGIC OF THE PROMPT EMISSION AND EARLY AFTERGLOW OF GRBS DETECTED BY FERMI The operation of Fermi boosted the capabilities to observe the High Energy (HE) emission of Gamma-Ray-Bursts (GRBs) The detection of the Very High Energy (VHE) emission from GRBs would provide an unprecedented opportunity to enlighten the nature of the central engine and the interaction between the relativistic flow and the environment of the burst progenitor. In order to address this issue, we propose simultaneous observations with the MAGIC Telescope of GRBs detected and followed up by Fermi. MAGIC, with an energy threshold below 100 GeV and repositioning time to any position in less than 100 seconds, is currently the best suited instrument to detect the VHE component of GRBs.
21166 J. HOLDER EXPLORING THE GEV-TEV CONNECTION IN LS I +61 303 WITH FERMI AND VERITAS The HMXRB LS I +61 303 is the only variable galactic gamma-ray source visible to VERITAS. Results from this season show strong evidence for an anti-correlation between the TeV and GeV emission from the system, possibly indicating that photon-photon absorption is the key element which determines the lightcurve structure. The GeV lightcurve is periodic, but also shows clear orbit-to-orbit variability. We will propose to support TeV observations, guided by the measured Fermi flux, to examine the most interesting emission states. The ultimate goal is to use the TeV- GeV connection to determine the nature of the compact object, and the high energy particle acceleration and photon production mechanisms at work.
21168 S. HUNTER MODEL OF THE GALACTIC DIFFUSE EMISSION FOR FERMI We propose to study the physical structure of the Milky Way Galaxy and the cosmic rays that pervade it by modeling the Galactic diffuse gamma-ray emission in terms of the interstellar medium, photon radiation, and cosmic ray distribution in the Milky Way Galaxy and comparing it with the FERMI all-sky observations. This work will also support the FERMI mission and the scientific community by providing an alternative model of the Galactic diffuse gamma-ray emission for point source analysis. Rather than fitting the FERMI data precisely, our emphasis will be on obtaining more general conclusions regarding Galactic structure and the Galactic cosmic-ray distribution, including the Galactic cosmic-ray halo.
21172 A. KONOPELKO A JOINT FERMI GST, MAGIC, AND VERITAS BROADBAND OBSERVATION CAMPAIGN ON ONE HIGH-ENERGY BLAZAR IN A MAJOR OUTBURST The main objective of the proposed work is to perform one very intense observational campaign at X-ray, GeV, and TeV energies of one of the well-established northern sky TeV blazars, i.e., Mkn 421, Mkn 501, 1ES 1959+650, H 1426+428, and 1ES 2344+514 with Fermi, MAGIC, and VERITAS. Simultaneous broadband observations of blazars in a flaring state provide an excellent test of emission models. Observations of blazars at GeV and TeV energies yields the profile of the spectral shape of the HE component of their emission.
21173 D. WILLIAMS OBSERVATIONS ABOVE 100 GEV OF GAMMA-RAY BURSTS DETECTED BY FERMI We propose to conduct follow-up observations with VERITAS at very high energy (VHE; >100 GeV) of GRBs detected by Fermi, to analyze the resulting data, and to engage in other activities to support the observations. Many afterglow emission models show the SEDs of GRBs to be similar to those of blazars and predict an inverse Compton component with luminosity comparable to the synchrotron component, extending to VHE energies. Yet this component has eluded definitive detection. Early results from Fermi reinforce the evidence from EGRET of delayed high-energy emission from some bursts, motivating a search for such emission at the still higher energies accessible to VERITAS.
21176 R. CORBET SEARCHING FOR NEW GAMMA-RAY BINARIES FROM PERIODIC VARIABILITY IN LAT LIGHT CURVES There are only 3 sources that are definitely known to be gamma-ray binaries. Two of these are listed as associations in the Fermi LAT Bright Source List. We propose here to use novel techniques to extract high SNR light curves of all cataloged Fermi sources and to search for periodic variability using appropriately weighted power spectra. The detection of periodic variability would be strong evidence of the detection of a new gamma-ray binary. The LAT's sensitivity provides the potential to open up completely new discovery space for additional binary systems, potentially involving novel astrophysics.
21177 E. GOTTHELF X-RAY AND GAMMA-RAY TIMING AND SPECTRAL STUDIES OF FIVE RADIO QUIET PULSARS Detecting gamma-ray emission from a full range of energetic, rotation-powered pulsars with Fermi is of great importance to fully understand particle acceleration in pulsar magnetospheres. In particular, to constrain emission models, deep searches are needed for 50MeV-10GeV emission from pulsars covering a large range of spin-down powers, B-fields & geometries. We request support to continue our RXTE X-ray timing of 5 exceptional radio-quiet pulsars that cover a large parameter space of pulsar properties. We will use our ephemerides to search Fermi data and place upper-limits on the pulsed flux, for non-detections, and to measure pulsed spectra at energies >200keV using archival hard X-ray data. We request GBT time for a deep radio search of one pulsar while the X-ray ephemeris is available
21183 J. HEWITT SUPERNOVA REMNANT MASERS AS SIGNPOSTS OF COSMIC RAY ACCELERATION We propose to search the Fermi LAT data for gamma-ray sources coincident with interacting supernova remnants traced by OH masers. Our initial analysis finds nine of 24 remnants with masers are coincident with gamma-ray sources. The observed luminosities can be explained by hadronic emission if a significant fraction of the supernova energy (5-30%) is diverted to cosmic-ray production. With Fermi gamma-ray emission can be localized spatially to confirm associations, and pion decay can be studied spectrally to measure the local cosmic ray energy density. Finally, we will use the gamma-ray detections to ascertain whether ionization by cosmic rays can explain the non-equilibrium shock chemistry which allows copious columns of OH to be produced under the conditions for masers to arise.
21185 S. RAZZAQUE PROBING THE GAMMA RAY OPACITY OF THE UNIVERSE USING THE HIGHEST ENERGY FERMI DATA Absorption of high-energy gamma rays by photons of the extragalactic background light (EBL) changes the received spectra of distant sources. Using gamma rays with energies E>10 GeV collected by the Fermi Gamma Ray Space Telescope from high-redshift gamma-ray bursts and blazars, we propose to constrain the gamma-ray opacity of the universe. The method is illustrated using Fermi Large Area Telescope (LAT) and Gamma-Ray Burst Monitor (GBM) observations of gamma rays from GRB 080916C. We also propose to examine the Fermi data base for the highest energy photons from GRBs and blazar AGNs in order to perform this study.
21188 J. ARONS TIME VARIABLE SYNCHROTRON GAMMA RAYS FROM PULSAR WIND NEBUALE: PROBING ASTROPHYSICAL PEVATRONS Kinetic plasma and relativistic MHD simulation and theoretical modeling of the termination shocks of the relativistic winds emerging from pulsars is proposed, as a tool to use the expected time variability of the synchrotron gamma ray emission as a probe of the particle acceleration processes that convert relativistic flow energy into the nonthermal particle distributions observed through their synchrotron emission. The models rely on the fact that the PeV electrons and positrons that radiate the ~ 20-100 MeV gamma rays have short synchrotron loss times, short enough to allow the emission to follow the variability built into the accelerating electromagnetic fields.
21193 M. CORCORAN OBSERVATIONS OF GAMMA-RAY EMISSION FROM ETA CAR AND WR 140 Massive binary stars can produce gamma-ray emission by Fermi acceleration of electrons to relativistic energies at the wind-wind collision shock (and possibly at the terminal wind-ISM shock boundary) through inverse Compton scattering. We propose to study the gamma-ray emission from two long-period, extremely eccentric colliding wind ``laboratories'', eta car and HD 193793 (= WR 140) using the LAT to study their high-energy emission along with our multi-wavelength variability monitoring from the radio to X-ray bands.
21199 T. JELTEMA FERMI OBSERVATIONS OF NEARBY, RADIO HALO CLUSTERS: PROBING COSMIC RAY AND DARK MATTER MODELS We propose to use the Fermi observations of nearby, radio halo clusters along with available radio and X-ray data to probe models of cosmic ray acceleration and particle dark matter. In particular, we will study the Coma and A2319 clusters, which host diffuse radio emission and are expected to be among the brightest clusters in gamma rays. With Fermi, we can measure or limit the energy density in cosmic ray protons, a currently unknown but very important contribution to the cluster energetics. We can also probe the dark matter particle mass and annihilation cross section. Combined with the radio and X-ray data, we can constrain the average cluster magnetic field. The gamma-ray and multiwavelength spectra can distinguish emission from dark matter annihilation and astrophysical cosmic rays.
21211 R. MUKHERJEE GEV/TEV BLAZAR POPULATION STUDIES WITH VERITAS AND FERMI We propose to improve our understanding of blazar population statistics and demographics by systematically looking at samples of VERITAS and Fermi blazars, with the aim of determining what fraction of blazars are gamma-ray emitters and at what levels and with what characteristic spectra. In particular, we will consider blazars for which there are existing VHE data and see what we can learn about them by adding the data now available from Fermi. We will carry out detailed physical modeling for those objects where we can assemble archival, high quality GeV-TeV lightcurves and spectra. We will also stack VHE and Fermi data on possible weaker sources like misdirected blazars to constrain or measure their mean emission, and we will compare these results with those for radio quiet objects.
21212 M. BRIGGS TERRESTRIAL GAMMA-RAY FLASH (TGF) OBSERVATIONS WITH GBM ON THE FERMI OBSERVATORY Terrestrial Gamma-Ray Flashes (TGFs) are brief (~ms), intense, single or multiple pulses of very energetic gamma rays, extending to >30 MeV, that are observed above thunderstorms. BATSE-CGRO discovered TGFs in 1994 and they have subsequently been observed by RHESSI, AGILE, and now, GBM on Fermi. The unique instrumental capabilities of GBM should allow significant advances in the understanding of TGFs by comparing them with new simulations of runaway electron showers that are produced by the intense electric fields of thunderstorms. A practical application of this research is the determination of significant radiation doses that are believed to be encountered by crew and passengers in aircraft flying in close vicinity to TGFs.
21216 N. GALANTE PROPOSAL FOR A FERMI-VERITAS JOINT OBSERVATION OF RADIO GALAXIES VERITAS observations of Fermi high-confidence radio galaxies provide crucial constraints to structured jet models. Long-term gamma-ray variability was shown in the EGRET object 3EG J0416+3650, which is associated with 3C 111. Currently, the only radio galaxies detected at VHE energies are M87 and NGC 5128. However, other radio galaxies are also suggested or confirmed as HE gamma-rays emitters. Fermi and VERITAS observations during flaring (or even quiescent) states offer to greatly expand our understanding of the high energy and very high energy emission in these objects.
21217 M. GEORGANOPOULOS WHERE DOES THE BLAZAR EMISSION COMES FORM AND WHAT DRIVES THEIR PHENOMENOLOGY? We propose to develop numerical models that will make use of Fermi data to (i) address the issue of the location of the blazar emission site relative to the broad line region, and (ii) unearth the dominant physical parameter behind the blazar sequence and, possibly, behind the multiwavelength variations of the quasar spectra. The codes we propose to develop, starting from our existing numerical work, will include pair production and particle acceleration considerations, both critical for addressing the above issues, and will produce broadband spectral energy distributions. The codes, together with practical manuals, will be posted on the web to be used by the Fermi community. The proposed research complements our running AFTP grant for blazar multizone variability modeling.
21219 V. PAVLIDOU ANISOTROPY AND ENERGY SPECTRUM OF THE GAMMA-RAY BACKGROUND AS PROBES OF DARK MATTER AND ASTROPHYSICAL SOURCES The gamma-ray background carries ample amounts of information about energetic and exotic processes in the universe. However, extracting this information is a difficult and complex problem, and requires careful control of uncertainties, degeneracies, and systematics. We propose a collaborative effort by researchers with diverse expertise in different aspects of theoretical modeling of the diffuse emission from different source classes and in a variety of analysis techniques. The goal of the proposed research is to develop methods for disentangling the different contributions to the gamma-ray background, and to identify a path to detecting, beyond degeneracies and confusion with astrophysical effects, a dark matter signature among diffuse Fermi photons, if one exists.
21220 A. FALCONE MULTIWAVELENGTH OBSERVATIONS AND ANALYSIS OF BLAZARS WITH SWIFT AND FERMI: SIMULTANEOUS OPTICAL/X-RAY/GAMMA-RAY SPECTRA This proposal aims to obtain multiwavelength data, specifically Swift (XRT, UVOT, BAT) data, on the "sources of interest" that will be monitored by Fermi and publicly released in the form of lightcurves and spectra. The proposal also aims to obtain contemporaneous Swift data during high states (defined by the Fermi-LAT team as flux > 2e-6 photons cm^-2 s^-1) from these sources or from any other new sources that exceed this threshold, thus triggering Fermi-LAT monitoring campaigns and public data release. As a Swift team member, the PI will work with the team to coordinate these observations and to maximize the science return by providing simultaneous multiwavelength observations that can be publicly accessed and analyzed.
21228 F. HARRISON GRB ENERGETICS IN THE FERMI ERA We propose a program of multiwavelength observations of Fermi gamma-ray bursts (GRBs) with the primary objectives of 1) identifying long-wavelength counterparts and 2) measuring beaming-corrected energies (burst plus afterglow) of the brightest and most energetic GRBs. Combined with ground-based optical (robotic Palomar 60-inch telescope) and radio (VLA) observations, we will use Fermi to target the high end of the GRB energy distribution - the recently discovered hyper-energetic (E > 10^52 erg) GRBs. This study will provide us with new insights into the least understood aspect of GRBs -- the central engine -- by constraining the maximum energy available for progenitor models (e.g. magnetars and black holes).
21240 T. MONTARULI SELECTION OF BLAZAR FLARES OF INTEREST FOR NEUTRINO EMISSION THROUGH THE STUDY OF MULTIWAVELENGTH DATA We propose a study of data from the Fermi-LAT as well as optical, X-ray and other gamma-ray data for the selection of blazar flares of interest in searches for correlated neutrino emission with neutrino telecopes such as IceCube or ANTARES. Multi-messenger studies such as the one proposed here can shed light upon and constrain blazar models involving accelerated hadrons predicting correlated gamma-ray and neutrino emission, as well as leptonic models predicting correlations between emissions of photons with different energies.
21242 D. POOLEY INVESTIGATING GLOBULAR CLUSTER DYNAMICS WITH FERMI The high sensitivity of Fermi will allow for the detection of the collective gamma-ray flux from a globular cluster's millisecond pulsar population for a number of clusters. Many globular clusters are expected to contain hundreds of millisecond pulsars, and the gamma-ray luminosity should scale as the number of pulsars. Fermi will, for the first time, be able to measure the total size of the millisecond pulsar population in a globular cluster; radio searches have completeness levels that are difficult, if not impossible, to quantify, and X-ray searches are not sensitive enough to blindly detect most millisecond pulsars. We will analyze the LAT data from all Galactic globular clusters to measure their gamma-ray luminosities and gain powerful insight into their internal dynamics.
21246 A. SPITKOVSKY GAMMA RAY EMISSION FROM PLASMA-FILLED PULSAR MAGNETOSPHERES Fermi observations of gamma-ray pulsars carry the promise of uncovering the inner workings of pulsar magnetospheres. To interpret the observed pulse profiles, however, a good model of the emission region is required. We propose to calculate the gamma ray lightcurves based on the geometry of the plasma-filled magnetosphere -- the 3D "force-free" solution. We propose to construct an atlas of lightcurves and spectra from the force-free magnetic geometry for comparison with the Fermi pulsar data. The emission zones will include the current sheet inside and outside the light cylinder. Particular attention will be paid to the possibility of light curves with many peaks (more than 2) that can occur in the emission from the current sheet.
21248 D. KOCEVSKI TIME RESOLVED SPECTROSCOPY OF GAMMA-RAY BURSTS We propose to focus on the time resolved spectral analysis of prompt GRB emission of events simultaneously detected by the Fermi and Swift spacecrafts. We estimate that 24 GRBs a year should be detected by both the Swift and Fermi spacecrafts as well as a smaller number of events detected exclusively by Fermi which will trigger subsequently XRT observations by Swift. This combination of a broad energy window to perform spectral evolution studies and a large sample of events with known redshift will represent a unique parameter set in GRB astronomy. We propose to concentrate our analysis on quantifying the evolution of GRB spectral parameters and how this evolution is related to a burst's source frame quantities such as the peak luminosity or total emitted energy Eiso.
21249 M. STAMATIKOS THE CROSS-CALIBRATION OF SWIFT-BAT AND FERMI-GBM VIA CORRELATIVE SPECTRAL ANALYSIS OF GRBS This is a resubmission of an accepted Cycle 1 proposal to cross-calibrate Swift's Burst Alert Telescope (BAT) and Fermi's Gamma-ray Burst Monitor (GBM), resulting in joint spectral GRB fits. Adding BAT's spectral response will (i) facilitate in-orbit GBM detector response calibration, (ii) augment Fermi's low energy sensitivity, (iii) enable ground-based follow-up efforts of Fermi GRBs, and (iv) help identify a subset of GRBs discovered via off-line GBM data analysis. The synergy of Swift and Fermi enables the study of peak energies, while leveraging the over eleven energy decades afforded by the (Cycle 2) inclusion of Fermi s Large Area Telescope (LAT). A status report on the first year's efforts is also included, which features preliminary joint fits to GRB 080810 as a case study.
21250 S. RANSOM SEARCHING FOR RADIO PULSARS IN FERMI BRIGHT UNIDENTIFIED SOURCES Fermi has been functioning spectacularly since its launch last summer, particularly in the field of pulsars. At least 15 brand new gamma-ray pulsars have been uncovered blindly and an additional 20+ radio pulsars have been detected in gamma-rays for the first time. As part of an international collaboration working with the Fermi team, we propose to search 27 of the unidentified sources in the initial Bright Source Catalog for radio pulsations at 820 MHz using NRAO's GBT. With significantly better sensitivity than previous searches of these regions, we expect to uncover several new gamma-ray bright radio pulsars.
21252 R. OJHA MULTIPLE RESOLUTION RADIO MONITORING OF SOUTHERN HEMISPHERE FERMI AGN & RAPID RADIO FOLLOW-UP OF FERMI FLARE DETECTIONS The TANAMI and associated programs provide comprehensive radio monitoring for Fermi sources south of declination -30 degrees where northern hemisphere facilities cannot observe. The TANAMI sample has shown an unprecedented detection rate of bright Fermi sources (~50%, based on the 3-month list) and currently, 20 of these are being monitored with milliarcsecond resolution by TANAMI. Supplementary to this, two radio telescopes at Hobart and Ceduna provide a single 1700km baseline to quickly followup flaring sources detected by Fermi. Quasi-contemporaneous radio data, is a vital component of the multiwavelength information suite needed to understand the physics of these sources. We seek partial support for data recording and processing hardware and travel related to these projects.
21254 R. KIPPEN CONTINUING TO OPTIMIZE GBM GRB LOCATION CAPABILITY TO ENABLE NEAR REAL-TIME OPTICAL FOLLOW-UP The Fermi Gamma-ray Burst Monitor (GBM) autonomously detects and locates ~200 gamma-ray bursts (GRBs) per year. This capability, combined with very wide field robotic telescope systems, could provide ground breaking prompt optical GRB observations. This requires minimizing time delay and location uncertainty while maximizing the number of locatable bursts. Current location algorithms do not include important effects due to spacecraft and atmospheric scatting. We propose to continue using the extensive GBM/Fermi modeling and simulation capability at Los Alamos to design optimized GRB location software algorithms that achieve these goals.
21260 M. LEISING FERMI GBM STUDIES OF DIFFUSE AND TRANSIENT EMISSION Simple detectors on stable platforms have proven extremely useful for studies of low energy gamma-ray emission. We propose to extend such studies using FERMI GBM data. In a few months of data, we see that the detectors and backgrounds and quite stable and that the backgrounds can be reasonably modeled with a relatively small number of parameters, for times sufficiently far from SAA passes. We expect to produce a reliable measurement of the galactic hard X-ray/soft gamma-ray spectrum and a realistic assessment of the feasibility of measuring the cosmic diffuse spectrum. The tools needed for these studies will aid studies of point-source occultations by others. As a by-product we can detect bright transients in a different part of parameter space from GBM triggers and occultation studies.
21261 P. SLANE A FERMI STUDY OF PARTICLE ACCELERATION IN G347.3-0.5 G347.3-0.5 (RX J1713.7-3946) is perhaps the most-studied candidate for cosmic-ray acceleration in SNRs, yet at present the origin of its gamma-ray emission is unclear. Hadronic models provide an adequate fit to the TeV spectrum, but appear inconsistent with limits on the thermal X-ray emission. Leptonic models, on the other hand, require a two-zone scenario in which the synchrotron-emitting electrons fill a smaller volume than those producing the inverse-Compton emission. Fermi LAT measurements will provide constraints that, combined with existing data, will differentiate between these scenarios. We propose a broad multiwavelength study of G347.3-0.5, incorporating Fermi LAT data as well as hydrodynamical modeling, to provide the definitive answer on the origin of its gamma-ray emission.
21263 A. WEINSTEIN CORRELATED ANALYSIS OF VERITAS AND FERMI DATA IN THE CYGNUS REGION OF THE GALACTIC PLANE. The VERITAS observatory has completed a deep VHE (E>100 GeV) gamma-ray survey of the Cygnus region between 67<l<82 and -1<b<4. This survey complements Fermi observations by virtue of its energy range, superior angular resolution, and comparative lack of diffuse gamma-ray background at TeV energies and supplies information not otherwise available to Fermi (e.g. the morphology of moderately extended Galactic sources). We propose to undertake a joint analysis of the Fermi and VERITAS survey data that exploits these constraints, developing the techniques required using VERITAS and Fermi simulation studies. To aid in interpretation, we also propose to assemble multi-wavelength data (primarily archival) to cover the VERITAS survey region in the infrared, radio, X-ray, and gamma-ray bands.
21266 V. MCSWAIN MULTIWAVELENGTH OBSERVATIONS OF THE GAMMA-RAY BINARY LS 5039 LS 5039 is an exceptionally rare example of a HMXB with MeV-TeV emission, making it one of only five known or proposed "gamma-ray binaries". It has long been modeled as a microquasar with stellar winds accreting onto a compact object, producing high energy emission and relativistic jets. However, its emission properties might also be explained by a relativistic pulsar wind colliding with the stellar wind. To resolve the controversy, we will exploit a unique opportunity to combine Fermi monitoring with a coordinated multiwavelength campaign. This Cycle 2 program will extend our ongoing and highly successful Cycle 1 monitoring at X-ray, optical, and radio wavelengths.
21267 A. PE'ER IDENTIFICATION OF THERMAL COMPONENTS IN GRB PROMPT EMISSION: A NEW TOOL FOR UNDERSTANDING UNDERLYING GRB PHYSICS We propose to identify and quantify the temporal behavior of thermal emission component in GRB prompt emission spectra. We then propose (1) to study the relation between the thermal and non-thermal components, in order to constrain emission models and progenitor models of GRBs; (2) to use the thermal emission to directly measure or constrain properties of the outflow, such as the radius of the photosphere and the bulk motion Lorentz factor. This could give additional, novel constraints on the properties of GRB progenitors.
21268 J. PRIMACK COSMOLOGY AND GAMMA-RAY ATTENUATION FOR AGN AND GRBS High-energy gamma-rays emitted by distant sources are attenuated due to pair production on the extragalactic background light (EBL). Our recent models of galaxy formation make predictions for gamma-ray attenuation due primarily to the UV background. We propose to update these models with the latest data and modeling techniques, and search for absorption in the spectra of AGN and GRBs that are observed by the LAT. We also wish to simulate the formation of pair halos around high-energy sources due to cascade interactions with the IR background, and calculate the effect of these interactions on the diffuse gamma-ray background. Finally, we will calculate the gamma-ray background spectrum from distant dark-matter annihilation, including the effects of attenuation by the EBL.
21270 C. CHEUNG RADIO/X-RAY STUDY OF HIGH-LATITUDE UNIDENTIFIED FERMI-LAT OBJECTS (UFOS) We propose a VLA study of 8 high Galactic latitude gamma-ray sources in the Fermi-LAT bright source list. These sources are currently unidentified, i.e., they are not clearly associated with established classes of gamma-ray emitters like blazars and pulsars. The proposed observations will determine the basic structure, spectra, and variability properties of radio sources within the Fermi-LAT localization circles, which together with follow-up at other wavelengths, aim to reveal the nature of the gamma-ray sources.
21271 I. MOSKALENKO STUDY OF THE EXTENDED EMISSION AROUND THE SUN DUE TO INVERSE COMPTON SCATTERING OF COSMIC-RAY ELECTRONS ON SOLAR PHOTONS The quiet Sun is a source of high-energy gamma rays, produced by cosmic ray (CR) nucleons interacting with the solar atmosphere (the albedo), and by CR electrons via inverse Compton (IC) scattering off solar photons in the heliosphere. The extended IC emission covers the whole sky with the maximum in the direction of the Sun and is a bright foreground for the diffuse extragalactic emission even at large elongation angles. Studies of the extended IC emission can provide invaluable information on modulation of CRs in the inner heliosphere from the close proximity to the Sun to Saturn's orbit at 10 AU. We propose to study the solar emission, including spectral analysis of the the disk and extended IC emission components, taking into account the contribution of gamma-ray sources.
21272 P. GONDOLO THE GAMMA-RAY/COSMIC-RAY DARK MATTER CONNECTION I propose new detailed studies of the expected dark matter signals in FGST in the light of recent new data on gamma-ray and cosmic-ray fluxes (FGST measurements of the diffuse gamma-ray emission, PAMELA observations of a positron excess, ATIC and FGST data on the electron spectrum). Constraints from accelerators and dark matter searches will be included. Particle physics models will comprise supersymmetric models, universal extra dimensions and models with enhanced e+e- production. Cosmological models will cover standard and non-standard scenarios with stronger dark halo substructure and dark matter signals. Cosmic ray fluxes will be updated to conform to the new theoretical models. State-of-the-art computer tools DarkSUSY and GALPROP will be used, and DarkSUSY will be upgraded.
21273 R. SHANNON A JOINT RADIO/GAMMA-RAY STUDY OF THE VARIABILITY OF THE CRAB PULSAR We propose to investigate the relationship between radio pulsar variability and gamma-ray emission by focusing on the connection between radio giant pulses and high energy emission from the Crab pulsar. A series of long dwells on this pulsar using the 34-m Goldstone Apple Valley Radio Telescope (GAVRT), which is equipped with a modern receiver and pulsar processor will provide an amplitude time series suitable for correlation with the LAT instrument on the Fermi Telescope. We will use these observations to determine if there is a modulation of gamma-rays during giant pulses and to test whether giant pulses are solely a radio-coherent phenomenon or reflect genuine changes in the particle flow in the magnetosphere
21283 R. MUKHERJEE USING FERMI TO UNDERSTAND THE CONTRIBUTIONS FROM UNRESOLVED DISCRETE SOURCES TO THE EXTRAGALACTIC G-RAY BACKGROUND We propose to study the high energy properties of AGNs and their contribution to the diffuse Extragalactic Gamma-Ray Background to understand the nature of this radiation. Using the EGRET data, we have recently carried out a study of the evolutionary properties and gamma-ray luminosity functions of BL Lacs and FSRQs. Despite careful analysis, this study had severe constraints arising from EGRET sensitivity limitations, leading to poorly-constrained source luminosity functions. Fermi, with its demonstrated ability to detect many more sources, including those belonging to additional AGN classes, can be used to significantly improve upon this work. We propose to carry out a similar analysis of the Fermi data to understand the contributions from unresolved discrete sources to the EGRB.
21284 F. CAMILO GREEN BANK TELESCOPE TIMING OF KEY FERMI PULSARS Energetic, young rotation-powered pulsars are one of the few important classes of objects being studied with Fermi. Because these pulsars display great rotational instability, appropriately folding the few gamma-ray photons obtained over months-to-years is impossible without contemporaneous radio observations, and such ground-based support work is being coordinated using telescopes worldwide. Half of the top 12 young radio candidates for gamma-ray study are extremely faint, and require the NRAO Green Bank Telescope for effective monitoring. Following the discovery of gamma-ray pulsations from at least four of these pulsars during Fermi Cycle 1, we here request the support and GBT time necessary to continue enabling this work.
21289 V. PETROSIAN FERMI OBSERVATIONS OF CLUSTERS OF GALAXIES AND THEORETICAL IMPLICATIONS Clusters of galaxies have not been detected at high energy gamma-rays, but the prospects of such detections with Fermi are quite high. We propose a year-long investigation of analysis of publicly available Fermi data on clusters of galaxies in parallel with theoretical investigation of acceleration and radiative processes. We will develop detailed predictions of spectra resulting from the inverse Compton, bremsstrahlung, and hadronic processes and investigate acceleration mechanisms involving shocks and turbulence, arising from merger or accretion activity. Actual detections or upper limits will be used to constrain the models.
21295 S. PROFUMO DMMW: A TOOL FOR MULTI-WAVELENGTH DARK MATTER SEARCHES We propose to develop a computational tool to predict the dark matter multi-wavelength (DMMW) annihilation spectrum for generic particle DM models. In the Fermi era, the identification of gamma-ray sources associated with DM annihilation will enormously benefit from the observation of secondary radiation produced by the electrons and positrons (e+e-) resulting from DM annihilation events. The MW spectrum extends from gamma-rays down to X-rays resulting from inverse Compton scattering of e+e- from DM, and to synchrotron radio-emission. The DMMW tool - which we plan to make readily publicly available and compatible with the Fermi Science Tools - will allow users to cross-correlate MW observations to constrain or to identify the nature of particle DM
21296 M. ROBERTS A PULSAR SURVEY OF FERMI SOURCES NOT IN THE BRIGHT SOURCE LIST We propose to search the Cycle 1 data for approximately 50 new sources not in the Bright Source List that could plausibly be pulsars and are viewable by the Green Bank Telescope. We ask for 30 hours of GBT time to survey these sources for radio pulsars at 350 MHz. This low observing frequency will make these observations very sensitive to nearby pulsars and millisecond pulsars sources off the Galactic plane, and the large beam will allow us to cover the Fermi error boxes with a single pointing. We will request follow-up timing observations of any discoveries to generate ephemerides which we will then use to search the cycle 2 Fermi data for pulsations.
21302 M. MCLAUGHLIN CONSTRAINING PULSAR EMISSION PHYSICS THROUGH RADIO/GAMMA-RAY CORRELATION OF CRAB GIANT PULSES We propose a comprehensive program of correlating radio giant pulses from the Crab pulsar with LAT photons. We will accumulate roughly 100,000 radio giant pulses with simultaneous LAT data by August 2010. This will allow sensitivity to gamma-ray flux variability at the few percent level, making this by far the most comprehensive radio/high-energy correlation study possible with current facilities. Our work also aims to test and further develop the first quantitative, theoretical model for giant-pulse emission. This project is important not only for constraining the giant-pulse emission mechanism, but for understanding the elusive pulsar emission mechanism in general and probing the exotic physics of relativistic particle acceleration in high magnetic fields.
21306 S. DJORGOVSKI CORRELATIVE SYNOPTIC MONITORING AND DISCOVERY OF BLAZARS Digital synoptic sky surveys from the ground can provide valuable synergistic opportunities which can greatly enhance the Fermi studies of blazars, ranging from their discovery to their physical understanding. We propose correlative studies using both real-time and archival data from several large, panoramic surveys, including PQ/NEAT (completed), CRTS (in progress and continuing), and PTF (forthcoming). This will include: (1) discovery of statistical samples of blazars on the basis of variability alone, and variability + multiwavelength data; (2) compilation and analysis of archival light curves; (3) discovery of blazars through optical flaring in real time; all of them correlated with the Fermi data. Synoptic surveys are complementary to targetted follow-up studies.
21307 R. CHATTERJEE INVESTIGATING THE LOCATION AND MECHANISM OF EMISSION IN THE JETS OF GAMMA-RAY BLAZARS USING TIME VARIABILITY The investigators propose to carry out analysis of the time variable emission of eight gamma ray blazars from Fermi and supporting multi-wavelength programs using robust and objective statistical techniques so that the physics extracted from these results is significant and unbiased. These include power spectral density (PSD), discrete cross-correlation function, and light curve decomposition which have been developed and used by the investigators in the past to analyze similar data. They have also developed a numerical model of the time variable emission in AGN jets which may be improved using the stronger constraints obtained from the above analysis. This study will add to the knowledge of the location and mechanisms of the time variable emission in the jets of AGNs.
21312 P. MESZAROS THEORETICAL MODELS OF GAMMA RAY BURSTS IN LIGHT OF THE FERMI LAT-GBM OBSERVATIONS This proposal focuses on theoretical investigations of the spectral properties of GRB observed by LAT/GBM. This will include the origin and mechanisms for the soft to hard to soft behavior of objects such as GRB080916C; the relationship between the spectral behavior of long and short bursts detected by LAT; constraints on the presence of spectral components expected from IC scattering or hadronic effects; and characterization of the constraints on Lorentz invariance violations.
21316 R. SAMBRUNA RELATIVISTIC JETS IN RADIO-LOUD NARROW LINE SEYFERT 1S? Circumstantial evidence suggests that a subclass of Narrow Line Seyfert 1s, dubbed ``radio-loud'', contains beamed relativistic jets: compact flat-spectrum radio emission, large-amplitude variability, and high brightness temperatures. Establishing the jet emission at high energies (X-ray to gamma-rays) can confirm the beamed nature of the emission from these sources and reveal possible analogies/differences with respect to the "classical" blazars detected in great numbers by Fermi. We propose to observe 23 radio-loud NLSy1 with Fermi to 1) search for their GeV emission and confirm the jet presence, and 2) assemble and model the SED of the best studied sources to derive quantitative physical parameters.