Recent extensions to GALPROP

Some recent extensions to the GALPROP cosmic-ray propagation package are described. The enhancements include: an accurate solution option, improved convection formulation, alternative spatial boundary conditions, polarized synchrotron emission, new magnetic field models, updated gamma-ray production cross-sections, free-free radio emission and absorption, primary positrons, additional injection spectral breaks, deuterium production by pp fusion, hadronic energy losses, improved HEALPix skymap format, compatibility with latest HEALPix release, and various bug fixes. The Explanatory Supplement has been extensively updated, including details of these enhancements. A compatible plot package GALPLOT for GALPROP output is also provided, as well as other related software.Comment: Contribution to the 34th International Cosmic Ray Conference, July 30 to August 6, The Hague, Netherland

Local interstellar cosmic-ray spectra derived from gamma-ray emissivities

Precise gamma-ray emissivities from cosmic-ray interactions with interstellar gas have been recently derived using Fermi-LAT data, and used to constrain the local interstellar spectra of protons and leptons. We report on a continuing effort to exploit these emissivities combined with the latest hadronic gamma-ray production cross-sections and other constraints such as synchrotron emission for the leptonic component. The interstellar spectra provide important information for heliospheric modulation, and cosmic-ray origin and propagation.Comment: Contribution to the 34th International Cosmic Ray Conference, July 30 to August 6, The Hague, Netherland

Interstellar gamma rays and cosmic rays: new insights from Fermi-LAT AND INTEGRAL

In over two years of operation Fermi-LAT has revolutionized our knowledge of the gamma-ray sky. Interstellar gamma rays are part of this new era and allow unprecedented tests for models of cosmic rays in the Galaxy. The extension to lower energies with INTEGRAL/SPI data is also evolving. The global multiwavelength luminosity of the Milky Way has been derived, with implications for the Galactic energy balance and the radio-FIR correlation.Comment: Accepted for publication in the Proceedings of the ICATPP Conference on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo (Como, Italy), 7-8 October, 2010, to be published by World Scientific (Singapore

Evaluation of ERTS data for certain oceanographic uses

The author has identified the following significant results. (1) Sunglint effects over water can be expected in ERTS-1 images whenever solar elevations exceed 55 deg. (2) Upwellings were viewed coincidently by ERTS-1 and NOAA-2 in Lake Michigan on two occasions during August 1973. (3) A large oil slick was identified 100 km off the Maryland coast in the Atlantic Ocean. Volume of the oil was estimated to be least 200,000 liters (50,000 gallons). (4) ERTS-1 observations of turbidity patterns in Lake St. Clair provide circulation information that correlates well with physical model studies made 10 years ago. (5) Good correlation has been established between ERTS-1 water color densities and NOAA-2 thermal infrared surface temperature measurements. Initial comparisons have been made in Lake Erie during March 1973

Evaluation of ERTS data for certain oceanographic uses

The author has identified the following significant results. Upwelling along the eastern shore of Lake Michigan was occurring during the 3 and 21 August 1973 visits by ERTS-1. The NOAA-2 VHRR thermal-IR data are being digitized for comparison. Early indications are that these upwellings induced a calcium carbonate precipitate to form in the surface waters. It is most pronounced in the MSS-4 channel. On the lake bottom this jell-like sediment is known as marl and adds to the eutrophication of the lake. This phenomenon may help to explain the varve-like nature of bottom cores that have been observed in the Great Lakes

Local electron spectrum above 100 MeV derived from gamma-ray emissivity spectra

Two new determinations of the local gamma-ray emmissivity spectrum are in good accord and were used to derive constraints on the local electron spectrum. The requirement for an electron intensity above 1 GeV larger than previously believed is confirmed and no low energy upturn is then needed

Gamma-ray emission from the solar halo and disk: a study with EGRET data

Context: The Sun has recently been predicted to be an extended source of gamma-ray emission, produced by inverse-Compton (IC) scattering of cosmic-ray (CR) electrons on the solar radiation field. The emission was predicted to be extended and a confusing foreground for the diffuse extragalactic background even at large angular distances from the Sun. The solar disk is also expected to be a steady gamma-ray source. While these emissions are expected to be readily detectable in the future by GLAST, the situation for available EGRET data is more challenging. Aims: The theory of gamma-ray emission from IC scattering on the solar radiation field by Galactic CR electrons is given in detail. This is used as the basis for detection and model verification using EGRET data. Methods: We present a detailed study of the solar emission using the EGRET database, accounting for the effect of the emission from 3C 279, the moon, and other sources, which interfere with the solar emission. The analysis was performed for 2 energy ranges, above 300 MeV and for 100-300 MeV, as well as for the combination to improve the detection statistics. The technique was tested on the moon signal, with our results consistent with previous work. Results: Analyzing the EGRET database, we find evidence of emission from the solar disk and its halo. The observations are compared with our model for the extended emission. The spectrum of the solar disk emission and the spectrum of the extended emission have been obtained. The spectrum of the moon is also given. Conclusions: The observed intensity distribution and the flux are consistent with the predicted model of IC gamma-rays from the halo around the Sun.Comment: Corrected typos, added acknowledgements. A&A in pres

Modelling cosmic rays and gamma rays in the Galaxy

An extensive program for the calculation of galactic cosmic-ray propagation has been developed. This is a continuation of the work described in Strong & Youssefi (1995). The main motivation for developing this code is the prediction of diffuse Galactic gamma rays for comparison with data from the CGRO instruments EGRET, COMPTEL, and OSSE. The basic spatial propagation mechanisms are (momentum-dependent) diffusion, convection, while in momentum space energy loss and diffusive reacceleration are treated. Primary and secondary nucleons, primary and secondary electrons, and secondary positrons are included. Fragmentation and energy losses are computed using realistic distributions for the interstellar gas and radiation fields. This study indicates that it is possible to construct a model satisfying a wide range of observational constraints and provides a basis for future developments.Comment: 5 pages including 7 figures, latex, aipproc.sty, aipproc.cls, epsfig.sty. To be published in Proc. 4th Compton Symp., 1997 (27-30 April, Williamsburg, Virginia). Details can be found at http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm