Looking for Light Pseudoscalar Bosons in the Binary Pulsar System J0737-3039

We present numerical calculations of the photon-light-pseudoscalar-boson conversion in the recently discovered binary pulsar system J0737-3039. Light pseudoscalar bosons (LPBs) oscillate into photons in the presence of strong magnetic fields. In the context of this binary pulsar system, this phenomenon attenuates the light beam emitted by one of the pulsars, when the light ray goes through the magnetosphere of the companion pulsar. We show that such an effect is observable in the gamma-ray band since the binary pulsar is seen almost edge-on, depending on the value of the LPB mass and on the strenght of its two-photon coupling. Our results are surprising in that they show a very sharp and significant (up to 50%) transition probability in the gamma-ray ($>$ tens of MeV) domain. The observations can be performed by the upcoming NASA GLAST mission.Comment: to appear in Phys. Rev. Let

A Zero-Order Flood Damage Model for Regional-Scale Quick Assessments

Quantitative data on observed flood ground effects are precious information to assess current risk levels and to improve our capability to forecast future flood damage, with the final aim of defining effective prevention policies and checking their success. This paper presents the first collection and analysis of flood damage claims produced in Italy in the past 7 years since a homogeneous national procedure for damage recognition became available. The database currently contains more than 70,000 claims referring to significant events and shows good homogeneity on the intensity of the related phenomena. We then propose an empirical model, based on observed data, to allow for a quick estimation of direct damage to private assets (i.e., residential buildings), based only on the knowledge of the perimeter of the flooded area. Single model calibration was performed at the multi-regional scale, focused on southern Italy. Model validation shows encouraging performances, considering the considerable natural uncertainty that characterizes this type of estimate. The procedure is of great interest when there is a need to evaluate, however roughly, flood damage in the immediacy of the event to assess the extent of the flood effects and to plan support actions for the affected communities

A variable absorption feature in the X-ray spectrum of a magnetar

Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are mainly powered by their own magnetic energy. This is supported by the fact that the magnetic fields inferred from several observed properties of AXPs and SGRs are greater than - or at the high end of the range of - those of radio pulsars. In the peculiar case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing parameters, whereas a strong field has been proposed to reside in the stellar interior and in multipole components on the surface. Here we show that the X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which depend strongly on the star's rotational phase. This line is interpreted as a proton cyclotron feature and its energy implies a magnetic field ranging from 2E14 gauss to more than 1E15 gauss.Comment: Nature, 500, 312 (including Supplementary Information

We are the Martians: Connecting Cosmology with Biology

What frightens you more? Believing you are alone in the universe or rather thinking that there’s someone else out there?   Human beings have been asking themselves this question for many thousands of years while looking at the starry sky. Over the past few decades, however, we have moved from imagination to action, exploring the cosmos using new techniques, often with surprising results. Did you know, for instance, that every year many rocks from Mars fall on the Earth? Or that one of our amino acids has been found in the coma of a comet? Or that we now know of thousands of extrasolar planets, some of them similar to our own?   There are further exciting and important discoveries around the corner that will cast more light on the great enigma of how life started on Earth. In this intriguing book, one of  the world’s leading researchers in astrophysics and space science examines fundamental questions concerning life on Earth and the rest of the cosmos in an accessible and stimulating way

The mystery of the seven spheres: how homo sapiens will conquer space

In this book, Giovanni Bignami, the outstanding Italian scientist and astronomer, takes the reader on a journey through the “seven spheres”, from our own planet to neighboring stars. The author offers a gripping account of the evolution of Homo Sapiens to the stage where our species is developing capabilities, in the form of new energy propulsion systems, that will enable us to conquer space. The reader will learn how we first expanded our activities to reach beyond our planet, to the Moon, and how nuclear energy, nuclear fusion, and matter–antimatter annihilation will enable us to extend our exploration. After Mars and Jupiter we shall finally reach the nearest stars, which we now know are surrounded by numerous planets, some of which are bound to be habitable. The book includes enticing descriptions of such newly discovered planets and also brings alive key historical characters in our story, such as Jules Verne and Werner von Braun

Imminent science: what remains to be discovered

This is not science fiction. It’s a voyage on the arrow of time to the coming fifty years. The legendary palindromic character Mr. Qfwfq from Italo Calvino’s collection of short stories, The Cosmicomics, will go with us – he who knows all the answers but will give out no hints. He will help us to discover the innovations that will have changed our lives by 2062, when, riding astride Halley’s Comet, our omniscient extraterrestrial will return to visit us.In this book, we shall learn how astronomers will devote themselves to the study of the mysterious force of dark energy, which makes up some three-quarters of the Universe. We shall also delve deeply into the study of our Earth, to exploit the immense thermal energy that lies beneath our feet. We shall solve another enigma in today’s science: the origin of life. We shall come to understand how to develop direct contacts between our brains and the rest of the world. We shall learn about the future of genetics, the reason for the longevity of Methuselah flies and the quest for prime numbers. These are only some of the exciting and important discoveries to be revealed in this intriguing book, which is designed for a broader public and not only for science fiction devotees