News & Press releases

Number of entries: 119

December 2017

Fifty years of pulsar astrophysics

Fifty years of pulsar astrophysics: an invited report, a new image and a video, produced for Nature Astronomy
The census of pulsars after 50 years of searching the radio to gamma-ray sky.
S. Serrano Elorduy (CSIC-IEEC) / N. Rea (CSIC-IEEC) / ATNF Pulsar Catalogue / HI4PI Collaboration / Nature Astronomy
In November 1967, after about two years mounting thousands of antennas, and connecting about a hundred miles of wires and cables over about four acres, the Cambridge PhD student Jocelyn Bell, noticed a strange signal in the data of her recently mounted telescope at the Mullard Radio Astronomy Observatory. Scanning a large part of the sky taking advantage of the Earth rotation, this new radio telescope soon produced a huge amount of data that Jocelyn Bell was promptly analyzing by hand, to study radio scintillation from many different astronomical sources.  However, very soon she came across a “scruff” signal, that she recognized as repeating every 1.33 seconds. These fast repetitions could not come from anything she was used to observe.
After a hectic time during Christmas holidays investigating over the nature of this “scruff” signal, carefully excluding any kind of man-made interference in the data, or the more exotic possibility of a “Little Green Man” trying to communicate with humans, Jocelyn Bell (now Professor) and her PhD supervisor Prof. Antony Hewish, recognized in this fast and periodic signal the possibility of it being produced by a compact star, dense and rapidly rotating star.
In fact, in the early  ‘30s, soon after the discovery of neutrons, many scientists predicted the existence of very compact and dense stars, made in large fraction by neutrons (spanning about 20km and as dense as atomic nuclei). These neutron stars were indeed predicted to be fast rotating, highly magnetic, and produced as left-overs of the death-end explosion of massive stars. In February 1968, the first pulsar discovery was published in the Nature magazine by Mrs. Bell, Prof. Hewish and collaborators.
Fifty years after this revolutionary discovery, Nature Astronomy publish a complete Issue celebrating the 50 years of pulsars, comprising several invited reports on different topics concerning pulsars. Nanda Rea from the Institute of the Space Sciences (IEEC-CSIC) has written a report for this issue, and Santiago Serrano Elorduy (IEEC-CSIC) has produced a new image and a video for Nature Astronomy showing the about 2500 pulsars discovered to date, as a function of time.
November 2017

Prof.S.D. Odintsov is 2017 Thomson-Reuters highly cited researcher (fourth year in a row)
Prof. S.D. Odintsov is 2017 Thomson-Reuters highly cited researcher (fourth year in a row)
October 2017

A new window to the knowledge of the Universe

A new window to the knowledge of the Universe
Contrapartida óptica de ondas gravitacionales
DES Collaboration 2017
On August 17th, the LIGO/VIRGO experiments detected simultaneously a strong gravitacional wave signal. The three detectors, which are located thousands of kilometres apart from each other, responded to a signal consistent with the collision of two neutron stars, never seen before. Almost simultaneously, the Fermi Gamma-ray Space Telescope from NASA observed a gamma-ray burst coming from the same direction in the sky. Several hours later, another team, using the DES camera and alerted but those first detections, captured the very first optical images of a gigantic cosmic explosion (a kilonova) coming from the same source, the Galaxy NGC 4993, located 130 millions light-years from Earth.
Several researchers from the Institute for Space Sciences (IEEC-CSIC) are actively participating on the DES and Fermi collaboration, the main actors of the electromagnetic counterpart discovery. Tens of observatories and thousands of astrophysicists coordinated to collect data on this extraordinary event. The variety of precision of the data obtained from this cosmic explosion and the future prospects, have generated great expectations on this new observational window.
The data also confirm models that predict the origin of heavy elements, such gold, platinum or uranium, which are found on Earth and other planetary systems. Together, all these measurements allow, among other things, for measurement of the expansion rate of the Universe or the understanding of new details about stellar and galaxy evolution.
For the first time, all the groups of the Institute of Space Science (IEEC-CSIC) working in topics as diverse as gravitational waves, fundamental physics, radioastronomy, millimetric astronomy, cosmology, stellar physics, astrophysics of high energies and X-rays, galaxy formation or planet search, have joined together to investigate a common event. 
October 2017

Scientists spot explosive counterpart of LIGO/Virgo’s latest gravitational waves

Scientists spot explosive counterpart of LIGO/Virgo’s latest gravitational waves
Contrapartida óptica de ondas gravitacionales
DES Collaboration 2017
Scientists using the Dark Energy Camera have captured images of the aftermath of a neutron star collision, the source of LIGO/Virgo’s most recent gravitational wave detection
A team of scientists using the Dark Energy Camera (DECam), the primary observing tool of the Dark Energy Survey, was among the first to observe the fiery aftermath of a recently detected burst of gravitational waves, recording images of the first confirmed explosion from two colliding neutron stars ever seen by astronomers.
Scientists on the Dark Energy Survey joined forces with a team of astronomers based at the Harvard-Smithsonian Center for Astrophysics (CfA) for this effort, working with observatories around the world to bolster the original data from DECam. Images taken with DECam captured the flaring-up and fading over time of a kilonova – an explosion similar to a supernova, but on a smaller scale – that occurs when collapsed stars (called neutron stars) crash into each other, creating heavy radioactive elements.
This particular violent merger, which occurred 130 million years ago in a galaxy near our own (NGC 4993), is the source of the gravitational waves detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo collaborations on Aug. 17. This is the fifth source of gravitational waves to be detected---the first one was discovered in September 2015, for which three founding members of the LIGO collaboration were awarded the Nobel prize in physics two weeks ago.
This latest event is the first detection of gravitational waves caused by two neutron stars colliding, and thus the first one to have a visible source. The previous gravitational wave detections were traced back to binary black holes, which cannot be seen through telescopes. This neutron star collision occurred relatively close to home, so within a few hours of receiving the notice from LIGO/Virgo, scientists were able to point telescopes in the direction of the event and get a clear picture of the light.
“This is beyond my wildest dreams,” said Marcelle Soares-Santos, formerly of the U.S. Department of Energy’s Fermi National Accelerator Laboratory and currently of Brandeis University, who led the effort from the Dark Energy Survey side. “With DECam we get a good signal, and we can show how it is evolving over time. The team following these signals is a well-oiled machine, and though we did not expect this to happen so soon, we were ready for it.”
The Dark Energy Camera is one of the most powerful digital imaging devices in existence. It was built and tested at Fermilab, the lead laboratory on the Dark Energy Survey, and is mounted on the National Science Foundation’s 4-meter Blanco telescope, part of the Cerro Tololo Inter-American Observatory in Chile, a division of the National Optical Astronomy Observatory. The DES images are processed at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.
Texas A&M University astronomer Jennifer Marshall was observing for DES at the Blanco telescope during the event, while Fermilab astronomers Douglas Tucker and Sahar Allam were coordinating the observations from Fermilab's Remote Operations Center. “It was truly amazing,” Marshall said. “I felt so fortunate to be in the right place at the right time to help make perhaps one of the most significant observations of my career.” 
The kilonova was first identified in DECam images by Ohio University astronomer Ryan Chornock, who instantly alerted his colleagues by email. “I was flipping through the raw data and I came across this bright galaxy, and saw a new source that was not in the reference image (taken previously),” he said. “It was very exciting.”
Once the crystal clear images from DECam were taken, a team led by Professor Edo Berger, from CfA, went to work analyzing the phenomenon using several different resources. Within hours of receiving the location information, the team had booked time with several observatories, including NASA’s Hubble Space Telescope and Chandra X-ray Observatory.
LIGO/Virgo works with dozens of astronomy collaborations around the world, providing sky maps of the area where any detected gravitational waves originated. The team from DES and CfA had been preparing for an event like this for more than two years, forging connections with other astronomy collaborations and putting procedures in place to mobilize as soon as word came down that a new source had been detected. The result is a rich data set that covers “radio waves to X-rays to everything in between,” Berger said.
“This is the first event, the one everyone will remember,” Berger said. “I’m extremely proud of our entire group, who responded in an amazing way. I kept telling them to savor the moment. How many people can say they were there at the birth of a whole new field of astronomy?”
Adding to the excitement of this observation, this latest gravitational wave detection correlates to a burst of gamma rays spotted by NASA’s Fermi Gamma-ray Space Telescope. Combining these detections is like hearing thunder and seeing lightning for the very first time, and it opens up a world of new scientific discovery.
“Each of these – the gravitational waves from merging neutron stars, the gamma ray burst and the optical counterpart – could have been separate ground-breaking discoveries, and each could have taken many years,” said Daniel Holz of the University of Chicago, who works on both the DES and LIGO collaborations.  “In less than a day, we did it all. This has required many different communities working together to make it all happen. It’s so gratifying to have it be so successful.”
This event also provides a completely new and unique way to measure the present expansion rate of the universe, the Hubble constant, something theorized by Holz and others. Just as astrophysicists use supernovae as “standard candles” (objects of the same intrinsic brightness) to measure cosmic expansion, kilonovae can be used as “standard sirens” (objects of known gravitational wave strength).
LIGO/Virgo can use this to tell the distance to these events, while optical follow-up from DES and others determines the redshift or recession speed; their combination enables scientists to determine the present expansion rate. This new kind of measurement will assist the Dark Energy Survey in its mission to uncover more about dark energy, the mysterious force accelerating the expansion of the universe.
“The Dark Energy Survey team has been working with LIGO for more than two years, refining their process of following up gravitational wave signals,” said Fermilab Director Nigel Lockyer. “It is immensely gratifying to be on the front lines of a discovery this significant, one that required the combined skills of many supremely talented people in many fields.”
The Dark Energy Survey recently began the fifth and final year of its quest to map an area of the southern sky in unprecedented detail. Scientists on DES will use this data to learn more about the effect of dark energy over eight billion years of the universe’s history, in the process measuring 300 million galaxies, 100,000 galaxy clusters and 3,000 supernovae.
Six papers relating to the DECam discovery of the optical counterpart are planned for publication in The Astrophysical Journal. Preprints of all papers are available here:
“It is tremendously exciting to experience a rare event that transforms our understanding of the workings of the universe,” says France A. Córdova, director of the National Science Foundation (NSF), which funds LIGO and supports the observatory where DECam is housed. “This discovery realizes a long-standing goal many of us have had, that is, to simultaneously observe rare cosmic events using both traditional as well as gravitational-wave observatories. Only through NSF’s four-decade investment in gravitational-wave observatories, coupled with telescopes that observe from radio to gamma-ray wavelengths, are we able to expand our opportunities to detect new cosmic phenomena and piece together a fresh narrative of the physics of stars in their death throes.”
The Dark Energy Survey is a collaboration of more than 400 scientists from 26 institutions in seven countries. Funding for the DES Projects has been provided by the U.S. Department of Energy Office of Science, U.S. National Science Foundation, Ministry of Science and Education of Spain, Science and Technology Facilities Council of the United Kingdom, Higher Education Funding Council for England, ETH Zurich for Switzerland, National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, Kavli Institute of Cosmological Physics at the University of Chicago, Center for Cosmology and AstroParticle Physics at Ohio State University, Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and Ministério da Ciência e Tecnologia, Deutsche Forschungsgemeinschaft, and the collaborating institutions in the Dark Energy Survey, the list of which can be found at 
Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
Fermilab is America’s premier national laboratory for particle physics and accelerator research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance LLC, a joint partnership between the University of Chicago and the Universities Research Association, Inc. Visit Fermilab’s website at and follow us on Twitter at @Fermilab.
The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit

Contact people:                         
Dr. Enrique Gaztañaga, Profesor de Investigación del  CSIC,
Dr. Ramon Miquel, Director del IFAE y Profesor de Investigación ICREA,
Dr. Eusebio Sánchez, Investigador Científico del  CIEMAT,
Dr. Juan García-Bellido, Profesor de la UAM y miembro del IFT,
October 2017

A paper signed by A. Serenelli is considered a highlight paper for 2017 by Astronomy & Astrophysics

A paper signed by A. Serenelli is considered a highlight paper for 2017 by Astronomy & Astrophysics
The paper titled "The brightness of the red giant branch tip. Theoretical framework, a set of reference models, and predicted observables" signed by A. Serenelli and four other authors, published by Astronomy & Astrophysics (A&A 606, A33), it is considered a Highlighted paper for 2017 by the publication.
September 2017

Josep Maria Trigo miembro de la Selección Española de Ciencia 2017

Josep Maria Trigo ha sido seleccionado como miembro de la Selección Española de Ciencia 2017 por la revista QUO
La revista de divulgación QUO, con la colaboración del CSIC y la secretaría de Estado de Innovación a seleccionado a nueve investigadores españoles como miembros de la Selección Española de Ciencia para 2017. Esta selección científica está formada por: Lluís Torner, Concha Monje, Ramón López de Mántaras, María Carmen Collado, Javier Tamayo, Antonio Figueras, Alejandro Ocampo y los astrofísicos Guillem Anglada-Escudé y Josep Maria Trigo, miembro este último del Instituto de Ciencias del Espacio. La entrega de los galardones se realizará a principios de octubre en la sede central del CSIC en Madrid.
September 2017

Exploring the Universe at the Highest Energies – the Cherenkov Telescope Array Releases its Updated Science Case

Libro de Ciencia de CTA
Science with the Cherenkov Telescope Array Cover
The latest iteration of the Cherenkov Telescope Array’s (CTA’s) science case, Science with the Cherenkov Telescope Array, was made available today via the CTA website library and will be published in a special edition of International Journal of Modern Physics D in the coming weeks. The work includes more than 200 pages that introduce and elaborate on CTA’s major science themes and place CTA in the context of other major observatories.
“The release of this document represents a major milestone for CTA, and it details the breadth and the richness of the science that will be done with the observatory over the next decade,” says CTA Co-Spokesperson Prof. Rene Ong. “The document would not have been possible without the hard work of literally hundreds of CTA Consortium members over a period of many years.”
CTA will be the foremost global observatory for very high-energy gamma-ray astronomy over the next decade and beyond. The scientific potential of CTA is extremely broad: from understanding the role of relativistic cosmic particles to the search for dark matter. CTA will explore the extreme Universe, probing environments from the immediate neighbourhood of black holes to cosmic voids on the largest scales. With its ability to cover an enormous range in photon energy from 20 GeV to 300 TeV, CTA will improve on all aspects of performance with respect to current instruments. And its wider field of view and improved sensitivity will enable CTA to survey hundreds of times faster than previous TeV telescopes.
CTA will seek to address a wide range of questions in astrophysics and fundamental physics that fall under three major study themes: understanding the origin and role of relativistic cosmic particles, probing extreme environments and exploring frontiers in physics (Chapter 1).
“The Key Science Projects described in the document – surveys and deep observations of key objects – will provide legacy data sets of lasting value and will provide important input for the planning of CTA's user programme,” said CTA Spokesperson Prof. Werner Hofmann.
Some of the most promising discoveries will come from a survey of our Milky Way galaxy, which should discover more Galactic sources for improved population studies and for advancing our understanding the origin of cosmic rays (Chapter 6); the Ramon y Cajal researcher from the Institute for Space Sciences (IEEC-CSIC) explains: "we will observe our Galaxy with a sensitivity 10 times better that with the current instruments, allowing us to finally understand long-standing questions such the origin of the cosmic rays, which have been eluding us for 100 years!";  the search for the elusive dark matter with models not accessible by other experiments (Chapter 4); and the detection of transient phenomena like gamma-ray bursts and gravitational wave events associated with catastrophic events in the Universe (Chapter 9).
“For me, the most exciting aspect of CTA is the potential for truly unexpected discoveries,” says CTA Project Scientist, Prof. Jim Hinton. “CTA pushes to shorter timescales, higher energies and more distant objects. Pushing back the frontiers in astronomy always leads to something truly new and exciting, and now we’re all just itching to get started.”
It has been a decade since science planning for CTA started, resulting in a series of publications in a special edition of Astroparticle Physics in 2013. The current work began that same year with an organized effort by the CTA Consortium to develop CTA’s Key Science Projects (KSPs) in 2013. After three years of development and refinement that including internal and external reviews, the KSPs were incorporated into a single document: Science with the Cherenkov Telescope Array.
Notes for Editors:
CTA ( is a global initiative to build the world’s largest and most sensitive high-energy gamma-ray observatory. More than 1,350 scientists and engineers from 32 countries are engaged in the scientific and technical development of CTA. The Observatory will be constructed by the CTAO gGmbH, which is governed by Shareholders and Associate Members from a growing number of countries.
CTA will serve as an open observatory to the world-wide physics and astrophysics communities. The CTA Observatory will detect high-energy radiation with unprecedented accuracy and approximately 10 times better sensitivity than current instruments, providing novel insights into the most extreme events in the Universe.
CTA is included in the 2008 roadmap of the European Strategy Forum on Research Infrastructures (ESFRI). This project is receiving funding from the European Union’s Horizon 2020 research and innovation programs under agreement No 676134. This project has received funding from the European Union’s Seventh Framework Programme ([FP7/2007-2013] [FP7/2007-2011]) under Grant Agreement 262053.
Contact Information:
Prof. Rene Ong, CTA Co-Spokesperson
Prof. Jim Hinton, CTA Project Scientist
Diego Torres,
Prof. Werner Hofmann, CTA Spokesperson

Prof. Ulrich Straumann, CTAO gGmbH Managing Director
Megan Grunewald, CTA Communications Officer
September 2017

Prime candidate to explain cosmic ray sea runs short of energy

The MAGIC telescopes have now observed that one of the best candidates of CRs acceleration, Cassiopeia A falls short of energy.
MAGIC telescopes
M. Lopez IAC
Cassiopeia A is a famous supernova remnant, the product of a gigantic explosion of a massive star about 350 years ago. Although discovered in radio observations 50 years ago, now we know that its emitted radiation spans from radio through high-energy gamma rays. It is also one of the few remnants for which the birth date and the type of supernova are known. It was a type IIb, the result of a core collapse supernova explosion -. The precise knowledge of its nature makes Cassiopeia A one of the most interesting and investigated objects in the sky, and in particular the study of its connection with the cosmic rays, sub-atomics particles that fill our Galaxy with energies higher than anything achievable in laboratories on Earth.
The very high-energy part of the spectrum of Cassiopeia A results from the cosmic rays (either electrons or protons) within the remnant. Until now, this range of energy could not be measured with sufficient precision to pinpoint its origin. Sensitive observations above 1 Tera-electronvolts (TeV) were required but achieving them was daunting. An international team led by scientists from the Institute for Space Sciences (ICE - IEEC-CSIC, Spanish National Research Council-CSIC), the Institut de Fisica d’Altes Energies (IFAE) and the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), in Spain, has finally succeeded in doing those observations with the MAGIC telescopes (short for Major Atmospheric Gamma-ray Imaging Cherenkov Telescope). More than 160 hours of data were recorded between December 2014 and October 2016, revealing that Cassiopeia A is an accelerator of massive particles, mostly hydrogen nuclei (protons). However, even when those particles are 100 times more energetics than the ones we can reach in artificial accelerators such the one in CERN, their energy is not hugh enough to explain the cosmic ray sea that fills our Galaxy.
“Cassiopeia A is the perfect object to be a PeVatron, that is, an accelerator of particles up to PeV energies (1 PeV = 1.000 TeV): it is young, bright, with a shock expanding a great velocity and with very large magnetic fields that can accelerate cosmic rays up to at least, conservatively, 100 or 200 teraelectronvolts” explains Emma de Oña Wilhelmi, scientist of CSIC in the Institute for Space Sciences, “But contrary to what we expected, in Cassiopeia A the particle energies do not reach more than a few tens of tera-electronvolts. At these energies, the radiation suddenly drops and the emission stops abruptly: Either the remnant cannot accelerate the particles to higher energies, which challenge our knowledge of shocks acceleration, or maybe, the fastest ones escaped quickly the shock, leaving only the slowest ones for us to observe”, adds Daniel Guberman, at the Institut de Fisica d’Altes Energies.
“Those supernovae are natural accelerators of particles, therefore the perfect laboratory to study charge particles and plasma in conditions that are not possible in our labs in Earth", remarks Daniel Galindo, working at Institute of Cosmos Sciences of the University of Barcelona (ICCUB). “To understand the origin of the cosmic rays implies to unveil the origin of our own Galaxy”, concludes Razmik Mirzoyan, MAGIC Spokeperson from the Max Planck Institute for Physics (MPP) in Munich (Germany).

MAGIC telescopes

MAGIC telescopes are located at the Roque de los Muchachos Observatory, in La Palma (Canary Islands). MAGIC, a system of two 17m diameter Cherenkov telescopes, is currently one of the three major imaging atmospheric Cherenkov instruments in the world. It is designed to detect photons tens of billions to tens of trillions times more energetic than visible light. MAGIC also uses a novel technique to reduce the effect of the Moonlight in the camera, allowing for observations during moderated Moonlight nights.
MAGIC has been built with the joint efforts of an international collaboration that includes about 160 researchers from Germany, Spain, Italy, Switzerland, Poland, Finland, Bulgaria, Croatia, India, Japan, Armenia and Brazil.

For more information on MAGIC, visit:

Published in the Monthly Notices of the Royal Astronomical Society (MNRAS, 2017): MAGIC Collaboration (M. L. Ahnen et al.) "A cut-off in the TeV gammaray spectrum of the SNR Cassiopeia A". DOI: 10.1093/mnras/stx2079
September 2017

ESA's INTEGRAL satellite selects a figure in one of our papers as picture of the month

A broad-band study of the 2015 outburst of EXO 1745-248 with INTEGRAL and XMM-Newton is chosen as INTEGRAL's result of the month
2015 outburst of EXO 1745-248 with INTEGRAL and XMM-Newton
Artist's rendering in upper right corner:
From the ESA website:

Low Mass X-ray Binaries (LMXBs), binary systems containing a compact object, are among the brightest and most extreme systems in the Universe. In these systems a neutron star (1.4-2 M⊙) or black hole (5-15 M⊙) accretes matter transferred by a low-mass (less than 1 M⊙) companion star. This matter in-spirals toward the compact object usually forming an accretion disk in which a large amount of potential energy is dissipated reaching temperatures of tens to hundreds of millions of degrees Kelvin and making LMXBs powerful sources in the soft and hard X-ray band. The low magnetic field of the compact objects allows the disk to extend to small radii, experiencing strong gravity and reaching high velocities, thus making these systems ideal laboratories to study the behavior of the accretion flow in the relativistic regime.

With the aid of the ESA missions XMM-Newton and INTEGRAL, a transient neutron star LMXB, EXO 1745-248, hosted in the Globular Cluster Terzan 5, has been studied during an X-ray outburst. The high-quality broad-band spectra provided by INTEGRAL have helped to constrain the continuum, dominated by a high-temperature (40 keV) thermal Comptonization, allowing the high energy resolution, spectroscopic instruments onboard XMM-Newton to unveil a wealth of narrow and broad emission lines superimposed to the continuum.

Features at energies compatible with K-α transitions of ionized Sulfur, Argon, Calcium, and Iron were detected, with a broadness compatible with Doppler broadening in the inner part of an accretion disk truncated at about 40 km from the neutron star center. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized Iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. The different ionization states and broadness suggest an origin in a region located farther from the neutron star than where the other emission lines are produced.

In the figure the light curve of the 2015 outburst displayed by EXO 1745-248 as observed by IBIS/ISGRI and JEM-X on board INTEGRAL is shown. For completeness, the light curve obtained from Swift/XRT (and published previously by Tetarenko, 2016) is also shown. The hard-to-soft spectral state transition of EXO 1745-248 around 57131 MJD is marked with a dashed vertical line in the plots. Around this date, the count-rate of the source in the IBIS/ISGRI decreases significantly, while it continues to increase in JEM-X. The times of the XMM-Newton observation are also marked by red dashed vertical lines. Broad-band spectra of the source during the outburst are also shown together with the best fit model (upper panel), and residuals in units of sigma with respect to the best fit model (bottom panel). The spectra from different instruments have been fitted simultaneously. These are XMM-Newton/RGS1 (red), XMM-Newton/RGS2 (green), XMM-Newton/EPIC-pn (black), INTEGRAL/JEMX1 (blue), INTEGRAL/JEMX2 (cyan), and INTEGRAL/ISGRI (magenta).

This study has been led by the University of Palermo (Italy) and the INAF - Astronomical Observatory of Rome (Italy), has been partially performed at the Institut de Ciéncies de l'Espai (IEEC-CSIC) in Barcelona (Spain), in collaboration with the ISDC - Data Centre for Astrophysics in Versoix (Switzerland), the University of Cagliari (Italy), and other European institutions.

Reference:"XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst",
M. Matranga, A. Papitto, T. Di Salvo, E. Bozzo, D. F. Torres, R. Iaria, L. Burderi, N. Rea, D. de Martino, C. Sanchez-Fernandez, A. F. Gambino, C. Ferrigno, L. Stella,
2017, A&A, 603, A39
August 2017

El Dark Energy Survey publica la medida más precisa de la estructura de la materia oscura en el universo

El Dark Energy Survey publica la medida más precisa de la estructura de la materia oscura en el universo
Mapa de la materia oscura realizada por el Dark Energy Survey
Chihway Chang del Kavli Institute for Cosmological Physics de la Universidad de Chicago, y la colaboración DES
El nuevo resultado compite en precisión con las medidas de la radiación de fondo de microondas y confirma que la materia oscura y la energía oscura componen la mayor parte del cosmos.

Investigadores del Centro de Investigaciones Energéticas, MedioAmbientales y Tecnológicas (CIEMAT) , el Institut de Ciències de l'Espai (IEEC-CSIC) , el Institut de Física d'Altes Energies (IFAE) y el Instituto de Física Teórica (UAM-CSIC) participan en el resultado.

Barcelona/Madrid, 3 de agosto de 2017

Imaginad plantar una semilla y ser capaces de predecir con gran precisión la altura exacta del árbol que crecerá a partir de ella. Ahora imaginad poder viajar hacia el futuro y hacer una fotografía que demuestre que vuestra predicción era correcta.

Si tomamos la semilla como el universo primitivo, y el árbol como el universo actual, podemos hacernos una idea de lo que la colaboración Dark Energy Survey (DES) acaba de hacer. En una presentación que tendrá lugar hoy en la reunión de la American Physical Society Division of Particles and Fields en el Fermi National Accelerator Laboratory, cerca de Chicago, investigadores de DES mostrarán la medida más precisa jamás hecha de la estructura a gran escala del universo actual. Los resultados también se presentarán el viernes 4 de agosto por la mañana en el Centro de Ciencias Pedro Pascual de Benasque, donde el director del proyecto DES, el Prof. Joshua Frieman, junto con otros varios investigadores de la colaboración, tanto españoles como extranjeros, y otros científicos, asisten a una reunión internacional para discutir los últimos resultados en las medidas del cosmos y su interpretación teórica.

Estas medidas de la cantidad y distribución de materia oscura en el cosmos actual se han hecho con una precisión que, por primera vez, rivaliza con la de las medidas del universo primitivo hechas por la misión espacial Planck de la Agencia Espacial Europea (ESA). El nuevo resultado del DES (el árbol, en la metáfora anterior) está cerca de las “predicciones” para el universo actual hechas a partir de las medidas de Planck del pasado lejano (la semilla). Los nuevos resultados permiten a los científicos comprender más sobre las maneras en que el universo ha evolucionado durante más de 14 mil millones de años.

“Por un lado es emocionante poder confirmar las predicciones del modelo estándar y aportar los resultados más precisos sobre el ritmo de crecimiento de estructuras cósmicas”, ha declarado Enrique Gaztañaga, investigador principal en el Institut de Ciències de l'Espai (IEEC-CSIC). ”Pero todavía no hemos encontrado una pista definitiva de por qué el universo se está acelerando.”

Lo más notable es que este resultado apoya la teoría de que el 26 por ciento del universo se compone una forma misteriosa de materia, conocida como materia oscura, y que el espacio está lleno de una energía oscura, también invisible, que está causando la expansión acelerada del universo y que representa el 70 por ciento de su composición. La energía oscura, en su forma más simple, fue planteada como hipótesis por primera vez por Albert Einstein hace un siglo.

Explorando 14 mil millones de años de historia cósmica

Paradójicamente, es más fácil medir la distribución de materia del universo en un pasado lejano de lo que es medirla hoy. En los primeros 400.000 años después del Big Bang, el universo estaba lleno de un gas incandescente, cuya luz sobrevive hasta nuestros días. El mapa de Planck de esta radiación cósmica de fondo de microondas nos da una instantánea del universo en ese momento temprano. Desde entonces, por un lado, la gravedad de la materia oscura ha atraído la masa y ha hecho que se formen estructuras en el universo a lo largo del tiempo. Por otro lado, la energía oscura, con su efecto repulsivo, ha estado combatiendo la atracción de la materia. Usando el mapa de Planck como punto de partida, los cosmólogos pueden calcular con precisión cómo se ha desarrollado esta batalla entre materia y energía oscuras a lo largo de más de 14.000 millones de años.

“Con estas fantásticas medidas, DES está empezando a mostrar la enorme capacidad que tiene para producir resultados que supongan un avance importante en nuestra comprensión del universo. Los próximos años nos pueden deparar sorpresas acerca del lado oscuro del universo”, ha dicho Eusebio Sánchez, el investigador responsable del proyecto en el CIEMAT.

Cosmología observacional de alta precisión

El instrumento principal de DES es la Dark Energy Camera que, con 570 megapíxeles, es una de las cámaras astronómicas más potentes existentes en la actualidad, capaz de capturar imágenes digitales de galaxias a ocho mil millones de años luz de la Tierra. La cámara se construyó y probó en Fermilab, el laboratorio principal del Dark Energy Survey, y el grupo español de la colaboración contribuyó decisivamente a su construcción, ya que fue responsable del diseño, fabricación y verificación del sistema electrónico completo, así como del sistema de guiado del Telescopio. Los investigadores de DES usan la cámara durante cinco años para estudiar un octavo del cielo con un detalle sin precedentes. El quinto año de observación comenzará a mediados de agosto.

"Es un placer ver como empiezan a llegar los resultados de un proyecto en el que los grupos españoles nos involucramos desde el principio, hace ya 12 años, y donde hemos hecho contribuciones muy relevantes", ha declarado Ramon Miquel, investigador principal de DES en el IFAE en Barcelona.

Los nuevos resultados publicados hoy se basan únicamente en datos recogidos durante el primer año de observación y cubren una trigésima parte del cielo. Los científicos de DES utilizaron dos métodos para medir la materia oscura. Primero, crearon mapas de posiciones de galaxias, y segundo, midieron con precisión las formas de 26 millones de galaxias

lejanas para cartografiar directamente los patrones de materia oscura a lo largo de miles de millones de años luz, usando una técnica llamada lente gravitacional.

Para realizar estas medidas de alta precisión, el equipo de DES ha desarrollado nuevas técnicas para detectar las diminutas distorsiones que las lentes gravitacionales producen en las imágenes que se obtienen de las galaxias lejanas, un efecto que ni siquiera es visible al ojo humano. Las nuevas técnicas hacen posible un avance revolucionario en la comprensión de estas señales cósmicas. En el proceso, crearon el mapa más grande jamás hecho de la materia oscura en el cosmos (ver imagen). El nuevo mapa de materia oscura es diez veces más grande que el que la propia colaboración DES publicó en 2015, y será finalmente tres veces más grande de lo que es ahora cuando se incluyan todos los datos de cinco años de observación.

Científicos del IFAE han sido líderes de una de las técnicas utilizadas en estas medidas, que correlaciona entre sí las posiciones de las galaxias cercanas con las formas de las galaxias lejanas, contribuyendo a la enorme precisión alcanzada. "Con las medidas que hemos hecho, hemos contribuido a entender mejor la relación que hay entre las galaxias y la materia oscura, que es un elemento crucial para realizar este análisis cosmológico", ha comentado Judit Prat, estudiante de doctorado en el IFAE y primera autora de uno de los artículos que se harán públicos hoy. El IEEC-CSIC ha participado en la creación de mapas de materia oscura, las simulaciones y el estudio de agrupamiento de galaxias. El CIEMAT también ha contribuido a la construcción de los catálogos de galaxias y el estudio del agrupamiento de las mismas. Los tres equipos españoles han tenido un papel clave dentro de la colaboración DES en la determinación de la distancia a las galaxias, que es un elemento esencial para poder interpretar los resultados que ahora se anuncian.

Personas de contacto:


Dr. Ramon Miquel, Director de IFAE y Profesor de Investigación ICREA,


Dr. Enrique Gaztañaga, Profesor de Investigación CSIC,


Dr. Eusebio Sánchez, Investigador Científico CIEMAT,


Dr. Juan García-Bellido, Profesor UAM y miembro IFT,

Información Adicional

Los resultados serán publicados el 3 de agosto en La presentación de los resultados se llevará a cabo a las 5 pm hora de Chicago (00:00 del viernes, hora peninsular española) y se transmitirá en vivo en:

The Dark Energy Survey es una colaboración de más de 400 científicos de 26 instituciones en siete países. Su instrumento principal, la Dark Energy Camera, de 570 megapíxeles, está montada en el telescopio Blanco de 4 metros en el Observatorio Interamericano de Cerro Tololo del National Optical Astronomy Observatory en Chile y sus datos se procesan en el National Center for Supercomputing Applications de Illinois en Urbana-Champaign. España fue el primer grupo internacional en unirse a Estados Unidos para fundar el proyecto DES y participa a través de tres instituciones, dos de ellas en Barcelona (el Institut de Ciències de l'Espai,IEEC-CSIC, y el Institut de Física d'Altes Energies, IFAE) y una en Madrid (el Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT).
Institute of Space Sciences (IEEC-CSIC)

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An institute of the Consejo Superior de Investigaciones Científicas
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