Aims. Gamma-ray line emission from the radioactive decay of 26 Al reflects nucleosynthesis in massive stars and supernovae. We use INTEGRAL 26 Al measurements to characterize the distribution and characteristics of 26 Al source regions throughout the Galaxy. Methods. The spectrometer SPI aboard INTEGRAL has accumulated over five years of data on 26 Al gamma-ray emission from the Galactic plane. We analyzed these data using suitable instrumental-background models and adopted sky distribution models to produce high-resolution 26 Al spectra of Galactic emission, spatially resolved along the Galaxy plane. Results. We detect the 26 Al line from the inner Galaxy at ∼28σ significance. The line appears narrow, and we constrain broadening in the source regions to <1.3 keV (2σ). Different sky distribution models do not significantly affect those large-scale results. The 26 Al intensity for the inner Galaxy is derived as (2.9 ± 0.2) × 10 −4 ph cm −2 s −1 rad −1 , consistent with earlier results from COMPTEL and SPI data. This can be translated to an 26 Al mass of 2.7 ± 0.7 M in the Galaxy as a whole. The 26 Al intensity is also confirmed to be somewhat brighter in the 4th than in the 1st quadrant (ratio ∼1.3 ± 0.2).

Context. The Scorpius-Centaurus association is the most-nearby group of massive and young stars. As nuclear-fusion products are ejected by massive stars and supernovae into the surrounding interstellar medium, the search for characteristic γ-rays from radioactivity is one way to probe the history of activity of such nearby massive stars on a My time scale through their nucleosynthesis. 26 Al decays with a radioactivity lifetime τ ∼1 My, 1809 keV γ-rays from its decay can be measured with current γ-ray telescopes. Aims. We aim to identify nucleosynthesis ejecta from the youngest subgroup of Sco-Cen stars, and interpret their location and bulk motion from 26 Al observations with INTEGRAL's γ-ray spectrometer SPI. Methods. Following earlier 26 Al γ-ray mapping with NASA's Compton observatory, we test spatial emission skymaps of 26 Al for a component which could be attributed to ejecta from massive stars in the Scorpius-Centaurus group of stars. Such a model fit of spatial distributions for large-scale and local components is able to discriminate 26 Al emission associated with Scorpius-Centaurus, in spite of the strong underlying nucleosynthesis signal from the Galaxy at large. Results. We find an 26 Al γ-ray signal above 5σ significance, which we associate with the locations of stars of the Sco-Cen group. The observed flux of 6 × 10 −5 ph cm −2 s −1 corresponds to ∼1.1 × 10 −4 M of 26 Al. This traces the nucleosynthesis ejecta of several massive stars within the past several million years. Conclusions. We confirm through direct detection of radioactive 26 Al the recent ejection of massive-star nucleosynthesis products from the Sco-Cen association. Its youngest subgroup in Upper Scorpius appears to dominate 26 Al contributions from this association. Our 26 Al signal can be interpreted as a measure of the age and richness of this youngest subgroup. We also estimate a kinematic imprint of these nearby massive-star ejecta from the bulk motion of 26 Al and compare this to other indications of Scorpius-Centaurus massive-star activity.

The Crab pulsar is a quite young famous pulsar which radiates multi-wavelength pulsed photons. The latest detection of GeV and TeV pulsed emission with unprecedented signal-to-noise ratio, supplied by the powerful telescopes: Fermi, MAGIC and VERITAS, challenges the current popular pulsar models, which can be a valuable discriminator to justify the pulsar high-energy-emission models.Our work is divided into two steps. First of all, taking reasonable parameters (the magnetic inclination angle α = 45 • and the view angle ζ = 63 • ), we use the latest high-energy data to calculate radio, X-ray, γ-ray and TeV light curves from a geometric view to obtain some crucial information on emission locations. Secondly, we calculate the phase-averaged spectrum and phase-resolved spectra for the Crab pulsar and take a theoretical justification from a physical view for the emission properies as found in the first step. It is found that a Gaussian emissivity distribution with the peak emission near the null charge surface in the so-called annular gap region gives the best modeled light curves. The pulsed emission of radio, X-ray, γ-ray and TeV are mainly generated from the emission of primary particles or secondary particles with different emission mechanisms in the nearly similar region of the annular gap located in the only one magnetic pole, which leads to the nearly "phasealigned" multi-wavelength light curves. The emission of peak 1 (P1) and peak 2 (P2) is originated from the annular gap region near the null charge surface, while the emission of bridge is mainly originated from the core gap region.The charged particles cannot corotate with the pulsar and escape from the magnetosphere, which determines the original flowing primary particles. The acceleration electric field and potential in the annular gap and core gap are huge enough in the several tens of neutron star radii. Thus the primary particles are accelerated to ultrarelativistic energies, and produce numerous secondary particles (pairs) in the inner region of the annular gap and core gap. We emphasize that there are mainly two types of pairs, i.e., one is curvature-radiation induced (CR-induced), and the other is inverse-Compton-scattering induced (ICS-induced). The phase-averaged spectrum and phase-resolved spectra from soft X-ray to TeV band are produced by four components: synchrotron radiation from CR-induced and ICS-induced pairs dominates the X-ray band to soft γ-ray band (100 eV to 10 MeV); curvature radiation and synchrotron radiation from the primary particles mainly contribute to γ-ray band (10 MeV to ∼ 20 GeV); ICS from the pairs significantly contributes to the TeV γ-ray band (∼ 20 GeV to 400 GeV).The multi-wavelength pulsed emission from the Crab pulsar can be well modeled with the annular gap and core gap model. To distinguish our single magnetic pole model from two-pole models, the convincing values of the magnetic inclination angle and the viewing angle will play a key role.