Gravitational wave astronomy
The Advanced Ligo and Advanced Virgo observatories announced the first detection of a gravitational waves that has been recorded by all three interferometers simultaneously. The paper describing the event has been published by PRL. The merger event itself, a binary black hole composed of a black hole with ~30 solar masses and another one with ~25 solar masses at a redshift of about 0.1, are matching nicely the previous detections:
The crucial part of this detection is that is has been seen by all three instruments. It is thus confirming the performance of the Virgo instrument that had been switched on only two weeks before this observation. It also illustrates the power of combining the data from the different instruments to significantly improve the localisation uncertainty of the origin of the gravitational wave. Using only data from the two Ligo detectors, the 90% uncertainty maps spans 1160deg^2 across the sky, impossible to scan with typical telescope searching for a counterpart/afterglow/etc. Adding the data from Virgo this region shrinks to less then 100deg^2!! This improvement is clearly visible in the skymaps below.
Regions of this size become accessible for pointing telescopes. As example: we managed to cover almost the complete region with H.E.S.S. observations searching for high-energy gamma rays emitted by the black hole merger. As everybody else we didn't see any... See GCN #21673 for a summary of our observations.
The importance of this event is thus primarily its illustration of the achieved precision of the GW localisation allowing for follow-up observations across the electromagnetic spectrum. Astronomy with gravitational waves is thus becoming a reality... Stay tuned for more...
I guess most colleagues in the high-energy astroparticle physics domain accepted the idea of the extragalactic origin of the highest energy cosmic rays (UHECR, E>10^18eV) a long time ago: we have already problems to find sources in our Galaxy which are able to accelerate particles up to the knee in the cosmic ray energy spectrum at around 10^15eV. It is therefore hard to imagine galactic accelerators reaching to the ultra-high energies. In addition, one would expect these UHECR particles to show a clear anisotropy toward the Galactic Plane if they were produced there, something that is not observed...
Nevertheless, the recent result of the Pierre Auger Collaboration does now provide further evidence for the extragalactic origin of UHECRs. As published in Science, 22 Sep 2017, the arrival direction of particles above 8*10^18eV shows a clear dipolar structure. The amplitude is much stronger than what would be expected from the Compton-Getting effect induced by the movement of the Earth with respect to the cosmic-ray background. Even more interesting, the direction of the dipole (black cross in the figure below) seems to be consistent with the distribution of galaxies in our neighborhood (once the potential magnetic deflections in the galactic magnetic field are taken into account). The direction of galaxy distribution dipole is given as "2MRS" in the figure below, possible magnetic deflections are indicated by the two arrows.
More about UHECRs (mainly my own contributions to the field) can be found here: Cosmic rays
Sky map in galactic coordinates showing the cosmic-ray flux for E ≥ 8 EeV smoothed with a 45° top-hat function. The galactic center is at the origin. The cross indicates the measured dipole direction; the contours denote the 68% and 95% confidence level regions. The dipole in the 2MRS galaxy distribution is indicated. Arrows show the deflections expected for a particular model of the galactic magnetic field on particles with E/Z = 5 or 2 EeV. (from Science, 22 Sep 2017 and arXiv:1709.07321)
40 years old and still rocking
No, not me... although close ;-) The NASA/JPL Voyager satellites just had their 40th birthday!
The two spacecraft have been launched in August and September 1977 and are still sending data which allow unprecedented studies of the solar system and its boundary the heliosphere. The current status of the mission and the instruments onboard is given here: Voyager mission status
Voyager 1 crossed into "Interstellar space" in 2012 and Voyager 2 is currently in the "heliosheath", the outermost layer of the heliosphere where the solar wind is slowed by the pressure of interstellar gas but still present. Voyage 1 therefore provides the first direct measurements of galactic cosmic rays, unaffected by the solar wind. In addition to the science program, the voyager crafts also provided the first and only pictures of our solar system from the 'outside'. Looking back towards the sun in 1990, voyager 1 took a series of 60 snapshots showing this family picture of 6 planets: