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237 May 29, 2015

AGILE: 8 and counting

"AGILE: 8 and counting", this was the title of the 13th AGILE Workshop celebrating the eighth anniversary of the launch of the AGILE satellite.

Since its launch on 23 April 2007, AGILE has made several important scientific discoveries, such as the variability of the Crab Nebula in gamma-rays, and the existence of a high-energy component in terrestrial gamma-ray flashes (TGF) produced in the Earth atmosphere.

The 13th AGILE Workshop was held in the ASI Headquarters on May 25-26, 2015. The slides of all contributions are publicly available at the workshop website.

A special ASI-TV report by G. Pulcrano was dedicated to AGILE in this occasion. The video (in italian) can be viewed here.



CREDITS: ASI-TV report by Giuseppina Pulcrano, ASI-TV Chief Editor: Manuela Proietti, Video Editor: Daniele Quatrini.

237 May 12, 2015

Asymmetric explosion of SN1987A from 44Ti emission lines revealed with NuSTAR

The NASA's high-energy X-ray observatory Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the supernova 1987A (SN1987A) allowed to resolve the 67.87 and 78.32 kiloelectron volt emission lines from decay of 44Ti produced in the supernova explosion. NuSTAR data showed that these two lines are narrow and redshifted with a Doppler velocity of ~700 kilometers per second, probing direct evidence of large-scale asymmetry in the explosion.

"Stars are spherical objects, but apparently the process by which they die causes their cores to be turbulent, boiling and sloshing around in the seconds before their demise," said Steve Boggs of the University of California, Berkeley, lead author of a new study on the findings, appearing in the May 8 issue of Science. "We are learning that this sloshing leads to asymmetrical explosions."

"Titanium is produced in the very heart of the explosion, so it traces the shape of the engine driving the disassembly of the star," said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology in Pasadena. "By looking at the shift of the energy of the X-rays coming from titanium, the NuSTAR data revealed that, surprisingly, most of the material is moving away from us."

Last year, NuSTAR created detailed 44Ti maps of another supernova remnant, called Cassiopeia A, also finding evidence of an asymmetrical explosion, though not to as great an extent as in 1987A. Together, these results suggest that lopsidedness is at the very root of core-collapse supernova.

NuSTAR brought a new tool to the study of supernovae. Thanks to the observatory's sharp high-energy X-ray vision, it has made the most precise measurements of 44Ti yet. This radioactive material is produced at the core of a supernova, so it provides astronomers with a direct probe into the mechanisms of a detonating star.

The Italian participation to NuSTAR includes the provision of the Malindi ground station (ASI), the ASI Science Data Center (ASDC), which contributes with the development of the NuSTARDAS software package and hosting an official mirror of the NuSTAR scientific public data archive, and a team of scientists of the Istituto Nazionale di Astrofisica (INAF) that actively collaborates on the primary scientific mission goals.

The NuSTAR team at ASDC is composed by M. Perri (INAF archive scientist), S. Puccetti (INAF archive scientist) and P. Giommi (ASDC Responsible).

For more details on NuSTAR, see:
http://nustar.asdc.asi.it
http://www.nustar.caltech.edu



Right: 59-80 keV NuSTAR spectrum of SN1987A with detected 44Ti emission lines. The observations indicate that supernovae belonging to a class called Type II or core-collapse blast apart in a lopsided fashion, with the core of the star hurtling in one direction, and the ejected material mostly expanding the other way (see model diagram at left).
[Credit: NASA/JPL-Caltech/UC Berkeley]


237 Apr 15, 2015

April 15-17: AMS Days at CERN

New results from AMS-02 are presented at CERN at the tree days event organized by the collaboration.
The event has been organized to understand the interrelation between AMS results and those of other major cosmic rays experiments and current theories.

Link to the original press release:
http://press.web.cern.ch/sites/press.web.cern.ch/files/file/press/2015/04/pr05.15e_ams_days_results.pdf

The "AMS Days" can be followed live:
https://webcast.web.cern.ch/webcast/play.php?event=381134

The program of the event:
https://indico.cern.ch/event/381134/timetable/#20150415

237 Mar 31, 2015

NuSTAR 6th Data Release at ASDC

The NuSTAR 6th Data Release is available from March 31, 2015 at ASDC. This new release contains 679 new data sets observed up to July 31, 2014.

All the NuSTAR public data at ASDC are fully integrated in the ASDC Multi-Mission Interactive Archive (MMIA). Through the MMIA the user can perform on-line analysis of all NuSTAR public observations, without the need to download any software, including the extraction of high-level scientific products (cleaned event files, sky images, energy spectra, light-curves, ARFs and RMFs).

For more details on NuSTAR, see:
http://nustar.asdc.asi.it/
http://www.nustar.caltech.edu/
http://heasarc.gsfc.nasa.gov/docs/nustar/

237 Feb 06, 2015

Planck 2015 release of data products and scientific papers: cosmic reionisation and first stars


Map of the Cosmic Microwave Background polarisation at large angular scales. Colours represent temperature anisotropies, while textures indicate polarisation direction. [Credit: ESA/Planck Collaboration]

On February 5, 2015, the Planck Collaboration released a new set of data products and scientific papers. New results are based on all the data collected throughout the mission, between 2009 and 2013. In addition to the intensity maps at all nine frequency bands observed by Planck, polarisation maps at four frequencies (30, 44, 70, and 353 GHz) are being released.

Planck polarisation data not only provides an independent confirmation of the basic cosmological picture drawn using CMB intensity from both 2013 and 2015 maps. In fact, studying the properties of CMB polarisation at large angular scales, Planck scientists concluded that the reionisation of the Universe due to first stars happened 550 million years after the Big Bang, more than 100 million years later than previously thought. So, the Dark Ages of the Universe ended later. This is of fundamental importance because that 100 million years difference is significantly reducing the tension between CMB results and current knowledge of first stars and early galaxies.

Polarisation doesn't mean only reionisation. Indeed, by analysing polarised maps at different frequencies, Planck scientists obtained new insights on the properties of the Galactic magnetic field. Planck's new findings include also neutrino physics and dark matter annihilation.

The whole list of Planck scientific results is much longer, as described in the papers that are available on ESA website. Planck public data products can be accessed through the Planck Legacy Archive. Additional results and products will be released in the forthcoming weeks.

For more information, see:
The ASDC team working on Planck-LFI consortium includes G. Polenta (archive scientist) and P. Natoli (senior scientist). Planck ERCSC and PCCS source catalogues are available on the ASDC website.

237 Feb 03, 2015

Results from Planck and BICEP2/Keck Array joint study: no conclusive evidence for primordial gravitational waves

On March 2014, the BICEP2 team announced for the first time a significant detection of a B-mode polarisation signal, and this was interpreted as the tiny imprints in the CMB field of the primordial gravitational waves produced during the inflationary epoch 10-34 s after the Big Bang.

However, some concerns about the cosmological origin of the detected signal were raised by the scientific community, as the instrument was observing at only one frequency band thus preventing to separate contributions from the Early and the local Universe. Doubts strengthened even more in September 2014, when the Planck Collaboration published the results from a study of the polarised emission of the interstellar dust at high galactic latitudes, including also the region of the sky observed by the BICEP2 telescope. Scientists therefore decided to join forces to take advantage of both the outstanding sensitivity of BICEP2/Keck Array and the wide frequency coverage of the Planck satellite.

On January 30, 2015, the results from the joint analysis of data from Planck, BICEP2, and Keck Array experiments were published, showing no evidence for a significant detection of primordial gravitational waves. In fact, when accounting for the contribution of polarised emission produced by the interstellar dust in the Milky Way, there is no statistical evidence for the presence of primordial gravitational waves signatures in the BICEP2 and Keck Array data.

However, inflation is not ruled out by the new results as gravitational waves might still be hiding deeper into the data: the quest for CMB B-mode polarisation is not over.

For more information, see:
The ASDC team working on Planck-LFI consortium includes G. Polenta (archive scientist) and P. Natoli (senior scientist). Planck ERCSC and PCCS source catalogues are available on the ASDC website.



Planck view of the submillimiter sky in the BICEP2 region. The colour scale represents the interstellar dust emission, while textures indicates the orientation of the Galactic magnetic field as derived from interstellar dust polarisation. The highlighted area shows the region observed by BICEP2 and the Keck Array.
[Image - Credit: ESA/Planck Collaboration]

237 Jan 20, 2015

NuSTAR Principal Investigator receives the 2015 Bruno Rossi Prize

We are pleased to report that the 2015 Bruno Rossi Prize of the High Energy Astrophysics Division (HEAD) of the American Astronomical Society has been awarded to the NuSTAR Principal Investigator Fiona Harrison for her "groundbreaking work on supernova remnants, neutron stars and black holes enabled by NuSTAR, the first satellite to focus X-rays at energies above 10 kiloelectron volts (keV)."

The citation for the Rossi Prize, the top prize in high-energy astrophysics, notes that Harrison's "assembly and leadership of the extraordinary NuSTAR team has opened a new window on the Universe." "The exciting scientific results from NuSTAR are the culmination of close to two decades of work by a talented and dedicated team," said Harrison. "It is a privilege to work with them, and an honor to be recognized through the Rossi Prize."

NuSTAR (Nuclear Spectroscopic Telescope Array) was launched in June 2012 under NASA's Small Explorer program. The primary science objectives are the study of the hottest, densest and most energetic phenomena in the universe, including the physics of massive black holes and collapsed stars, the explosion dynamics and nucleosynthesis in supernovae, and the particle acceleration in relativistic jets in Active Galactic Nuclei.

The Italian participation to NuSTAR includes a) the provision of the Malindi ground station (ASI), b) the support of the ASI Science Data Center (ASDC), which has developed and maintains the NuSTARDAS data analysis software package and hosts an official mirror of the NuSTAR scientific data archive, and c) a team of scientists of the Istituto Nazionale di Astrofisica (INAF) and of Italian Universities to collaborate on the primary scientific mission goals.

This is the fifth time that a space mission for which the ASDC plays an important role has been awarded a Rossi Prize, after BeppoSAX in 1998, Swift in 2007, Fermi in 2011 and AGILE in 2012.



Fiona A. Harrison, Benjamin M. Rosen Professor of Physics at Caltech.
Credit: Lance Hayashida/Caltech

237 Sep 23, 2014

NuSTAR 5th Data Release at ASDC

The NuSTAR 5th Data Release is available from September 23, 2014 at ASDC. This new release contains 214 new data sets of 28 distinct targets observed up to June 30, 2014, including all the calibration observations of the Crab.

All the NuSTAR public data at ASDC are fully integrated in the ASDC Multi-Mission Interactive Archive (MMIA). Through the MMIA the user can perform on-line analysis of all NuSTAR public observations, without the need to download any software, including the extraction of high-level scientific products (cleaned event files, sky images, energy spectra, light-curves, ARFs and RMFs).

For more details on NuSTAR, see:
http://nustar.asdc.asi.it/
http://www.nustar.caltech.edu/
http://heasarc.gsfc.nasa.gov/docs/nustar/

237 Sep 19, 2014

Latest AMS-02 Results published on PRL

After one year of intensive analysis the AMS-02 Collaboration has released the long-awaited extended results on the positron fraction and a new measurement of the electron and positron fluxes up to unprecedented energies.

These results provide new insights into the nature of the mysterious excess of positrons observed in the flux of cosmic rays and were presented in a conference at CERN by the AMS02 spokesperson, the Nobel laureate professor Samuel Ting, on September 18th, just before their publication in the Physics Review Letters Journal.

41 billion primary cosmic ray events have been analyzed among which almost 10 million have been identified as electrons and positrons. The energy at which the positron fraction ceases to increase has been measured to be 275+/-32 GeV and the distribution of these events shows no preferred incoming direction from space. Between 20 and 200 GeV, the rate of change of the positron flux is surprisingly higher than that for electrons. This is important proof that the excess seen in the positron fraction is due to a relative excess of high-energy positrons, and not the loss of high-energy electrons.

Data are already available for download on the ASDC Cosmic Rays Database.

PRL Publications:

"High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5500 GeV with the Alpha Magnetic Spectrometer on the International Space Station" 10.1103/PhysRevLett.113.121101

"Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station" 10.1103/PhysRevLett.113.121102

CERN press release

INFN press release (italian)

Webcast of the seminar at CERN