News & Press releases

Number of entries: 90

05
December 2018

Un censo de la población de magnetares


La astrofísica Nanda Rea, del Instituto de Ciencias del Espacio, desarrollará un censo de magnetares
Dr. Nanda Rea
La astrofísica Nanda Rea, del Instituto de Ciencias del Espacio (ICE, CSIC), recibe 2,3 millones de euros para el proyecto MAGNESIA, titulado Censo de magnetares: el impacto de estrellas de neutrones altamente magnéticas en el universo explosivo y transitorio. “Nuestro proyecto se centra en los magnetares, las estrellas de neutrones más magnéticas, a los que se ha relacionado con una gran variedad de acontecimientos explosivos”, explica Rea. “Su enorme poder de rotación y la tremenda cantidad de energía magnética que liberan, los relaciona con estallidos de rayos gamma, las fases iniciales de la fusión de estrellas de neutrones, supernovas superluminosas, hipernovas, estallidos de radio y fuentes de rayos X ultraluminosas”, añade. “El censo de magnetares en nuestra galaxia está subestimado, y esto lastra nuestra comprensión no sólo de las poblaciones de púlsares y magnetares, sino también su posible relación con muchos de los acontecimientos explosivos del universo”, indica la investigadora.

El Proyecto MAGNESIA desarrollará un exhaustivo censo de los magnetares mediante una aproximación innovadora que elaborará el primer modelo sintético de población de púlsares capaz de encajar con los límites de observaciones multi-banda, teniendo en cuenta modelos en 3D de evolución de campos magnéticos e índices de destello de estrellas de neutrones”, explica Rea. “El proyecto MAGNESIA solucionará las cuestiones de física, los errores observacionales sistemáticos y los desafíos computacionales que lastraban los trabajos previos, para restringir el periodo de giro y la distribución del campo magnético en el nacimiento de la población de estrellas de neutrones”, añade la investigadora.

Vídeo NewCompStar: Exploring fundamental physics with compact stars (en inglés).

(Esta nota de prensa es un extracto de la creada por el Departamento de Comunicación del CSIC que puede verse pinchando aquí).
21
November 2018

From gamma rays to X-rays: new method pinpoints previously unnoticed pulsar emission


Discovery of pulsed X-ray emission from three pulsars as predicted by a new theoretical model
Animated GIF of PSR J1826-1256
Based on a new theoretical model, a team of scientists explored the rich data archive of ESA's XMM-Newton space observatory to find pulsed X-ray emission from three systems. The discovery, relying on gamma-ray observations of the same sources, provides a novel tool to investigate the mysterious mechanisms of pulsar emission, which will be important to understand these fascinating objects and use them for space navigation in the future.

Lighthouses of the Universe, pulsars are fast-rotating neutron stars that emit beams of radiation. As pulsars rotate and the beams alternatively point towards and away from Earth, the source oscillates between brighter and dimmer states, resulting in a signal that appears to 'pulse' every few milliseconds to seconds, with a regularity rivalling even atomic clocks.

Pulsars are the incredibly dense, extremely magnetic, relics of massive stars, and are amongst the most extreme objects in the Universe. Understanding how particles behave in such a strong magnetic field is fundamental to understanding how matter and magnetic fields interact more generally.

Originally detected through their radio emission, pulsars are now known to also emit other types of radiation, though typically in smaller amounts. Some of this emission is standard thermal radiation - the type that everything with a temperature above absolute zero emits. Pulsars release thermal radiation when they accrete matter, for example from another star.

But pulsars also emit non-thermal radiation, as is often produced in the most extreme cosmic environments. In pulsars, non-thermal radiation can be created via two processes: synchrotron emission and curvature emission. Both processes involve charged particles being accelerated along magnetic field lines, causing them to radiate light that can vary in wavelength from radio waves to gamma-rays.

Non-thermal X-rays result mostly from synchrotron emission, while gamma-rays may come from a mixing, referred to as synchro-curvature emission. It is relatively easy to find pulsars that radiate gamma-rays: NASA's Fermi Gamma-Ray Space Telescope has detected more than 200 of them over the past decade, thanks to its ability to scan the whole sky. But only around 20 have been found to pulse in non-thermal X-rays. 

"Differently to surveying instruments in gamma-rays, X-ray telescopes must be told exactly where to point" says Diego Torres, from the Institute of Space Sciences in Barcelona, Spain.
Aware that there should be many pulsars emitting previously undetected non-thermal X-rays, Torres developed a model that combined synchrotron and curvature radiation to predict whether pulsars detected in gamma-rays could also be expected to appear in X-rays.

"Scientific models describe phenomena that can't be experienced directly" explains Torres. "This model in particular helps explain the emission processes in pulsars and can be used to predict the X-ray emission that we should observe, based on the known gamma-ray emission.
The model describes the gamma-ray emission of pulsars detected by Fermi, specifically, the brightness observed at different wavelengths, with three parameters. These determine the pulsar emission, thus predicting their brightness at other wavelengths, for instance in X-rays."
Torres partnered with a team of scientists, led by Jian Li from the Deutsches Elektronen Synchrotron in Zeuthen near Berlin, Germany, to select three known gamma-ray emitting pulsars that they expected, based on the model, to also shine brightly in X-rays. They dug into the data archives of ESA's XMM-Newton and NASA's Chandra X-ray observatories to search for evidence of non-thermal X-ray emission from each of them.

"Not only did we find X-ray emission from all three of the pulsars, but we also found that the spectrum of X-rays was almost the same as predicted by the model" explains Li. "This means that the model very accurately describes the emission processes within a pulsar."

In particular, XMM-Newton data showed clear X-ray emission from PSR J1826-1256, a radio quiet gamma-ray pulsar with a period of 110.2 milliseconds. The spectrum of light received from this pulsar was very close to that predicted by the model. X-ray emission from the other two pulsars, which both rotate slightly more quickly, was revealed using Chandra data.

This discovery already represents a significant increase in the total number of pulsars known to emit non-thermal X-rays. The team expects that many more will be discovered over the next few years as the model can be used to work out where exactly to look for them.

Finding more X-ray pulsars is important for revealing their global properties, including population characteristics. A better understanding of pulsars is also essential for potentially taking advantage of their accurate timing signals for future space navigation endeavours.

The result is a step towards understanding the relationships between the emission by pulsars in different parts of the electromagnetic spectrum, enabling a robust way to predict the brightness of a pulsar at any given wavelength. This will help us better comprehend the interaction between particles and magnetic fields in pulsars and beyond.

"This is one of very few pulsar models that can make accurate predictions of pulsar X-ray emission, and it also predicts the emission at other wavelengths, for example visible and ultraviolet" Torres continues. "In the future, we hope to find pulsars emitting other types of radiation based on the model. New findings would improve the model, leading to even more discoveries."
The study highlights the benefits of XMM-Newton's vast data archive to make new discoveries and showcases the impressive abilities of the mission to detect relatively dim sources. The team is also looking forward to using the next generation of X-ray space telescopes, including ESA's future Athena mission, to find even more pulsars emitting non-thermal X-rays.

"As the flagship of European X-ray astronomy, XMM-Newton is detecting more X-ray sources than any previous satellite. It is amazing to see that it is helping to solve so many cosmic mysteries" concludes Norbert Schartel, XMM-Newton Project Scientist at ESA.

Notes for Editors
Theoretically motivated search and detection of non-thermal pulsations from PSRs J1747-2958, J2021+3651, and J1826-1256? by Li et al is published in Astrophysical Journal Letters (URL and DOI to be added)

For more information, please contact:

Jian Li
Deutsches Elektronen Synchrotron DESY
Zeuthen, Germany
Email: jian.li@desy.de

Diego Torres
Institute of Space Sciences (ICE, CSIC)
Institut d'Estudis Espacials de Catalunya (IEEC)
Institució Catalana de Recerca i Estudis Avançats (ICREA) 
Barcelona, Spain
Email: dtorres@ice.csic.es

Norbert Schartel
XMM-Newton Project Scientist
European Space Agency
Email: norbert.schartel@esa.int

(This note has been elaborated by ESA)
14
November 2018

Our stellar neighbourhood is getting crowded — Planet discovered orbiting the second closest stellar system to the Earth


Measurements from high-precision instruments reveal a cold super-Earth around Barnard’s star
Artist’s impression of Barnard’s Star planet under the orange tinted light from the star.
IEEC/Science-Wave - Guillem Ramisa
  • Measurements from high-precision instruments reveal a cold super-Earth around Barnard’s star 
  • An international team of astronomers led by Ignasi Ribas of the Institute of Space Studies of Catalonia (IEEC) and Institute of Space Sciences (ICE, CSIC) has found a candidate planet in orbit around Barnard’s star.
  • Barnard’s star is the closest single star to the Sun and second only to the Alpha Centauri triple stellar system.
  • The team used about 18 years of observations and combined them with new observations with the CARMENES planet-hunter spectrograph at Calar Alto/Spain and other facilities.
  • Astronomers obtained significant evidence of a planet with mass just over 3 times the Earth’s mass orbiting the red dwarf star every 233 days. This would place the super-Earth near the so-called snow-line of the star, where it is likely to be a frozen world.
  • This is the first time astronomers discover this kind of exoplanet using the radial velocity method [1].
  • The finding will be published in the journal Nature on 15 November 2018. 
At only six light-years from us, Barnard’s star appears to move across Earth’s night sky faster than any other star. This red-dwarf star, smaller and older than our Sun is among the least active red dwarfs known and represents an ideal target to search for exoplanets with various methods.
 
Since 1997, several instruments have been gathering a large amount of measurements on the star’s subtle back-and-forth wobble. An analysis of the data collected up to 2015, including observations from HIRES/Keck, and ESO’s HARPS and UVES spectrometers, suggested the wobble could be caused by a planet with an orbital period of about 230 days. To confirm this, however, more measurements were deemed necessary.
 
Trying to see if the result could be confirmed, astronomers regularly monitored Barnard’s star with high precision spectrograph such as the CARMENES (Calar Alto Observatory in Spain), and also HARPS and HARPS-N in an international effort called the Red Dots collaboration [2]. This technique consists on using the Doppler effect on the starlight [1] to measure how the velocity of an object along our line of sight changes with time.
 
“For the analysis we used observations from seven different instruments, spanning 20 years, making this one of the largest and most extensive datasets ever used for precise radial velocity studies. The combination of all data led to a total of 771 measurements,” explains Ignasi Ribas.
 
A clear signal at a period of 233 days arose again in the re-analysis of all the measurements combined. This signal implies that Barnard’s star is approaching and moving away from us at about 1.2 m/s — approximately the walking speed of a person — and it is best explained by a planet orbiting it.
 
“After a very careful analysis, we are over 99% confident that the planet is there, since this is the model that best fits our observations,” assures Ignasi Ribas. “However, we must remain cautious and collect more data to nail the case in the future, because natural variations of the stellar brightness resulting from starspots can produce similar effects to the ones detected.” Follow-up observations are already happening at different observatories.
The planet candidate, named Barnard’s star b (or GJ 699 b), is a super-Earth with a minimum of 3.2 Earth masses. It orbits its cool red parent star every 233 days near the snow-line, a distance where water would be frozen. In the absence of an atmosphere, its temperature is likely to be about -150 ºC, which makes it unlikely that the planet can sustain liquid water on its surface. However, its characteristics make it an excellent target for direct imaging using the next generation of instruments such as NASA’s Wide Field InfraRed Survey Telescope (WFIRST, [3]), and maybe with observations from the ESA mission Gaia [4].
 
Exoplanets so small and so far away from their parent star have not been discovered before using the Doppler technique [1]. This means that astronomers are getting better at finding and exploring a relatively new kind of planets outside our Solar System. With the next generation of instruments, these capabilities can only expand.
 
“We all have worked very hard on this result,” said Guillem Anglada-Escude from Queen Mary University of London and co-leader of this work. “This is the result of a large collaboration organised in the context of the Red Dots project, which is why it has contributions from teams all over the world including semi-professional astronomers coordinated by the AAVSO.”
 
Cristina Rodríguez-López, researcher at the Instituto de Astrofísica de Andalucía (IAA, CSIC) and co-author of the paper, comments on the significance of this finding. "This discovery means a boost to continue on searching for exoplanets around our closest stellar neighbours, in the hope that eventually we will come upon one that has the right conditions to host life".

Notes
 
[1] In the radial velocity method, precision spectrometers are used to measure the Doppler effect. When an object moves away from us, the light we observe becomes slightly less energetic and redder. The opposite -light becomes slightly more energetic and bluer- happens when the star comes to us.
[2] RedDots is a collaborative observational effort dedicated to searching for terrestrial planets in warm orbits around the nearest red-dwarf stars to the Sun.
[3] WFIRST is a planned NASA mission that will be dedicated to answer cosmological questions, and also enable the detection of very nearby exoplanets with direct imaging.
[4] Gaia is an astrometric space mission from the European Space Agency (ESA) that is currently measuring precise positions and motions of stellar objects.

Observatories and Instruments
The CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) instrument is a high-resolution optical and near infrared spectrograph built in collaboration by various Spanish and German research institutions, and it is operated by the Calar Alto observatory (Spain).
 
The European Southern Observatory (ESO) operates two facilities used in this research, namely the HARPS and UVES instruments. HARPS (High Accuracy Radial velocity Planet Searcher) is dedicated to the discovery of exoplanets at the ESO 3.6-metre telescope (La Silla, Chile). UVES (Ultraviolet and Visual Echelle Spectrograph) is a high-resolution optical spectrograph at ESO’s Very Large Telescope (Paranal, Chile).
 
HIRES (High Resolution Echelle Spectrograph) is a high-resolution spectrograph at the W. M. Keck Observatory (Mauna Kea, Hawaii).
 
PFS (Planet Finder Spectrograph) is a high-resolution precision spectrograph at the Magellan 6.5m telescopes (Las Campanas Observatory, Chile).
 
APF (Automated Planet Finder) is a 2.4m telescope with a custom-made high-resolution precision spectrograph for precision radial velocities at the Lick observatory (California, USA).
 
HARPS-North (or HARPS-N) is a replica of ESO’s HARPS installed at the Telescopio Nazionale Galileo/Italy (La Palma, Spain).
 
Several observatories contributed to follow-up activities through the RedDots project, including observers from the AAVSO (American Association of Variable Star Observers). The AAVSO is an association formed by amateur astronomers that collect, evaluate, analyse, publish and archive variable star observations. These observations will be presented in more detail in a forthcoming publication.

Links
- Research paper
- IEEC
- RedDots

More information
This research is presented in a paper entitled “A super-Earth planet candidate orbiting at the snow-line of Barnard’s star”, by I. Ribas et al., to appear in the journal Nature on 15 November 2018.
 
IEEC (Institut d’Estudis Espacials de Catalunya) is a research institute dedicated to the study of all areas of space and space sciences including astrophysics, cosmology, planetary sciences, Earth observation, and space engineering; and it is integrated in the CERCA network (Centres de Recerca de Catalunya). Its mission is the promotion and coordination of space research and technology development in Catalonia for the benefit of the broader society. IEEC is integrated by four units : Institute of Cosmos Sciences (ICCUB - Universitat de Barcelona), Center of Space Studies and Research (CERES - Universitat Autònoma de Barcelona), Research Group in Space Sciences and Technologies (CTE - Universitat Politècnica de Catalunya), Institute of Space Sciences (ICE - Consejo Superior de Investigaciones Científicas). IEEC is a highly ranked international research center producing a large number of high-impact publications; and it leads key world-class projects. IEEC’s engineering division also develops instrumentation for multiple ground-based and space-based projects, and has extensive experience in working with aerospace and technology in both the private and public sectors.

Contacts
IEEC Public Information Office
Barcelona, Spain Miquel Sureda
Content SWaver
Science-Wave for IEEC
Tel: (0034) 661 46 35 37
E-mail: comunicacio@ieec.cat  
Lead Scientist
Bellaterra, Spain Ignasi Ribas
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE, CSIC)
E-mail: iribas@ice.cat
(This note has been elaborated by IEEC)
16
October 2018

DESI Collaboration Meeting in Barcelona


DESI Collaboration Meeting organized by ICE in Sant Feliu de Guíxols
DESI Collaboration Meeting in Barcelona
The DESI Collaboration Meeting is organized this time by members of ICE (IEEC-CSIC) in Sant Feliu de Guíxols (Girona, Catalonia, Spain) from October 16th – 20th, 2018. In this meeting will participate around one hundred researchers.

The meeting web page is: https://www.ice.csic.es/indico/event/11/page/2, while the web page of the project is: https://www.desi.lbl.gov/
16
October 2018

La Dra. Nanda Rea rep el Premi Nacional de Recerca en la categoria Talent Jove


El 15 d'octubre, l'astrofísica de l'ICE Dra. Nanda Rea va rebre el Premi Nacional de Recerca en la categoria Talent Jove
Dra. Nanda Rea després de rebre el seu premi
El 15 d'octubre, l'astrofísica de l'ICE (IEEC-CSIC) Dra. Nanda Rea, investigadora titular del CSIC, va rebre el Premi Nacional de Recerca en la categoria Talent Jove convocants per la Fundació Catalana per a la Recerca i la Innovació.
10
October 2018

Inauguració del primer telescopi d’una xarxa de telescopis Txerenkov


Inauguració del primer dels telescopis Txerenkov que es construeix a La Palma (Illes Canàries, Espanya)
El primer telescopi de la xarxa CTA nord
Daniel López / IAC
Inauguració del primer telescopi d’una xarxa de telescopis Txerenkov

La Palma, Illes Canàries, Espanya. – El dimecres 10 d’octubre de 2018, més de 200 assistents d’arreu del món es van reunir a la seu nord del Cherenkov Telescope Array (Xarxa de Telescopis Txerenkov, CTA) per assistir a la inauguració del primer Large-Sized Telescope (telescopi de gran mida, LST). El telescopi, anomenat LST-1, serà el primer de quatre LST a la part nord de l’Observatori CTA, el qual es troba al Observatorio del Roque de los Muchachos, a l’illa de La Palma i gestionat per l’Instituto de Astrofísica de Canarias. Un cop acabada, la xarxa nord estarà formada també per 15 telescopis de mida mitjana (Medium-Sized Telescopes, MSTs).
L’equip del LST està format per més de 200 científics de deu països: Brasil, Croàcia, França, Alemanya, Índia, Itàlia, Japó, Polònia, Espanya i Suècia. En aquest context internacional, el disseny i la gestió es va dur a terme conjuntament pel Laboratori d’Annecy de Física de Partícules (LAPP); l’Institut de Física Max Plank de Munic (Alemanya); l’Institut Nacional de Física Nuclear d’Itàlia; l’Institut de Recerca de Raigs Còsmics de la Universitat de Tokio (Japó), l’Institut de Física d’Altes Energies (IFAE) de Barcelona i el Centre d’Investigacions Energètiques Mediambientals i Tecnològiques de Madrid (CIEMAT). Entre les entitats participants en la construcció també hi ha l’Institut de Ciències del Cosmos de la UB (ICCUB-IEEC), l’Institut de Ciències de l’Espai ICE (IEEC-CSIC).
 
El 9 d'octubre de 2015 es va fer la celebració de la primera pedra de la construcció del LST-1. Un cop es van completar els fonaments del telescopi (gener del 2017), l'equip va continuar anant assolint les fites de la construcció, com la instal·lació del sistema de rails (setembre del 2017), i el muntatge dels miralls (desembre del 2017). El febrer del 2018, es va completar l'estructura del LST-1 i el suport de la càmera es va instal·lar al juny. Finalment, la instal·lació de la càmera –la fase final- es va completar el 25 de setembre del 2018.
Contribucions locals al projecte LST-1
Tres centres de recerca catalans han tingut una participació important en el desenvolupament tecnològic del LST-1. L’Institut de Física d’Altes Energies (IFAE) ha estat responsable de la coordinació, el control i l’assemblatge de la càmera del LST-1 així com del disseny i l’assemblatge del sistema mecànic que permet girar el telescopi i ancorar-lo a terra. L’Institut de Ciències del Cosmos de la UB (ICCUB-IEEC) ha contribuït al disseny d’un dels dispositius d’amplificació del senyal. L’Institut de Ciències de l’Espai, ICE (IEEC-CSIC), ha participat en el desenvolupament del software de control i el scheduler.  Totes tres institucions han contribuït a la definició dels objectius científics del projecte.
 
Detecció de raigs gamma
A banda del LST, es necessiten dos tipus telescopis més per poder estudiar el rang d’energia de 20 gigaelectró-volts (GeV) a 300 teraelectró-volts (TeV): els telescopis de mida mitjana i els de mida petita (mèdium-sized telescopes i small-sized telescopes). Com que els raigs gamma amb energia baixa produeixen poca llum Txerenkov, es necessiten els telescopis amb miralls grans per capturar les imatges. Per tant, es situaran quatre telescopis LST tant a la part nord com a la sud de l’observatori CTA, per cobrir la sensibilitat de la baixa energia entre 20 i 150 GeV dels CTA.
El LST té una superfície reflectora parabòlica de 23 metres de diàmetre, la qual s’aguanta amb una estructura tubular feta de fibra de carbó i tubs d’acer. La superfície reflectora de 400 metres quadrats capta i enfoca la llum del Txerenkov cap a la càmera, on els tubs fotomultiplicadors converteixen la llum en senyals elèctrics que es processen per l’electrònica de la càmera.  Encara que el LST-1 fa 45 metres d’alçada i pesa unes 100 tones, és extremadament ràpid i pot reposicionar-se en tan sols 20 segons per poder arribar a captar senyals breus de raigs gamma de baixa energia.  
Els LST ampliaran l'abast de la ciència a distàncies cosmològiques i a fonts més febles amb espectres d'energia sua. Tant la velocitat de reorientació dels telescopis com el llindar d'energia baix que proporcionen són elements clau pels estudis de fonts transitòries de raigs gamma en la nostra galàxia i per a l'estudi dels nuclis galàctics actius i les explosions de raigs gamma amb un alt en desplaçament cap al roig.
S’espera que el prototip sigui el primer telescopi LST del CTA, i, de fet, el primer telescopi en una seu de CTA, per a ser operat per l'Observatori CTA (CTAO). Però, com qualsevol altre lliurament tècnic en el gran projecte multinacional CTA, el LST-1 necessitarà passar un procés de revisió per poder verificar que el disseny compleix amb els objectius científics de CTA, les necessitats d’explotació, estàndards de seguretat, etc. abans de ser aprovat pel CTAO.
Podeu visitar el web de la inauguració del LST-1 (https://www.cta-observatory.org/lst-1_inauguration) per a més informació  en altres llengües i enllaços a més materials, imatges i vídeos.
 
09
August 2018

Finding the Happy Medium of Black Holes


Important evidence for populations of intermediate-mass black holes has been found.
Scientists have taken major steps in their hunt to find black holes that are neither very small nor extremely large. Finding these elusive intermediate-mass black holes could help astronomers better understand what the "seeds" for the largest black holes in the early Universe were.

The new research comes from two separate studies, each using data from NASA's Chandra X-ray Observatory and other telescopes. 

Black holes that contain between about one hundred and several hundred thousand times the mass of the Sun are called "intermediate mass" black holes, or IMBHs. This is because their mass places them in between the well-documented and frequently-studied "stellar mass" black holes on one end of the mass scale and the "supermassive black holes" found in the central regions of massive galaxies on the other.

While several tantalizing possible IMBHs have been reported in recent years, astronomers are still trying to determine how common they are and what their properties teach us about the formation of the first supermassive black holes.

One team of researchers used a large campaign called the Chandra COSMOS-Legacy survey to study dwarf galaxies, which contain less than one percent the amount of mass in stars as our Milky Way does. (COSMOS is an abbreviation of Cosmic Evolution Survey.) The characterization of these galaxies was enabled by the rich dataset available for the COSMOS field at different wavelengths, including data from NASA and ESA telescopes.

The Chandra data were crucial for this search because a bright, point-like source of X-ray emission near the center of a galaxy is a telltale sign of the presence of a black hole. The X-rays are produced by gas heated to millions of degrees by the enormous gravitational and magnetic forces near the black hole.

"We may have found that dwarf galaxies are a haven for these missing middleweight black holes," said Mar Mezcua of the Institute of Space Sciences in Spain who led one of the studies. "We didn't just find a handful of IMBHs — we may have found dozens."

Her team identified forty growing black holes in dwarf galaxies. Twelve of them are located at distances more than five billion light years from Earth and the most distant is 10.9 billion light years away, the most distant growing black hole in a dwarf galaxy ever seen. One of the dwarf galaxies is the least massive galaxy found to host a growing black hole in its center.

Most of these sources are likely IMBHs with masses that are about ten thousand to a hundred thousand times that of the Sun. One crucial result of this research is that the fraction of galaxies containing growing black holes is smaller for less massive galaxies than for their more massive counterparts.

A second team led by Igor Chilingarian of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., found a separate, important sample of possible IMBHs in galaxies that are closer to us. In their sample, the most distant IMBH candidate is about 2.8 billion light years from Earth and about 90% of the IMBH candidates they discovered are no more than 1.3 billion light years away.

With data from the Sloan Digital Sky Survey (SDSS), Chilingarian and his colleagues found galaxies with the optical light signature of growing black holes and then estimated their mass. They selected 305 galaxies with properties that suggested a black hole with a mass less than 300,000 times that of the Sun was lurking in the central regions of each of these galaxies.

Only 18 members of this list contained high quality X-ray observations that would allow confirmation that the sources are black holes. Detections with Chandra and with XMM-Newton were obtained for ten sources, showing that about half of the 305 IMBH candidates are likely to be valid IMBHs. The masses for the ten sources detected with X-ray observations were determined to be between 40,000 and 300,000 times the mass of the Sun.

"This is the largest sample of intermediate mass black holes ever found," said Chilingarian. "This black hole bounty can be used to address one of the biggest mysteries in astrophysics."

IMBHs may be able to explain how the very biggest black holes, the supermassive ones, were able to form so quickly after the Big Bang. One leading explanation is that supermassive black holes grow over time from smaller black holes "seeds" containing about a hundred times the Sun's mass. Some of these seeds should merge to form IMBHs. Another explanation is that they form very quickly from the collapse of a giant cloud of gas with a mass equal to hundreds of thousands of times that of the Sun.

Mezcua and her team may be seeing evidence in favor of the direct collapse idea, because this theory predicts that the less massive galaxies in their sample should be less likely to contain IMBHs.

"Our evidence is only circumstantial because it's possible that the IMBHs are just as common in the smaller galaxies but they're not consuming enough matter to be detected as X-ray sources", says Mezcua's co-author Francesca Civano of the CfA.

Chilingarian's team has a different conclusion.

"We're arguing that just the presence of intermediate mass black holes in the mass range we detected suggests that smaller black holes with masses of about a hundred Suns exist," says Chilingarian's co-author Ivan Yu. Katkov of Moscow State University in Russia. "These smaller black holes could be the seeds for the formation of supermassive black holes."

Another possibility is that both mechanisms actually occur. Both teams agree that to make firm conclusions much larger samples of black holes are needed using data from future satellites. The paper by Mar Mezcua and colleagues was published in the August issue of the Monthly Notices of the Royal Astronomical Society and is available online. The paper by Igor Chilingarian was recently accepted for publication in The Astrophysical Journal and is available online.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
30
July 2018

Press-release of Kazan Federal University about recent PRD paper by S D Odintsov and V Oikonomou has attracted a lot of attention on main news portals in Russia /https://www.cnnews.press/science/possible-death


Press-release on recent PRD paper by S D Odintsov and V Oikonomou
Recent PRD work by S D Odintsov and V K Oikonomou is devoted to study of possible future singularity of universe in frames of F(R) gravity. The method of dynamical system is used for that purpose. It is shown that for some DE models of F(R) gravity including quadratic on curvature terms the future singularity maybe avoided.
For detail:
.
Dynamical Systems Perspective of Cosmological Finite-time Singularities in f(R)f(R) Gravity and Interacting Multifluid Cosmology 
S. D. Odintsov (ICREA, Barcelona & ICE, Bellaterra & Barcelona, IEEC & Kazan State U.), V. K. Oikonomou (Aristotle U., Thessaloniki & TUSUR, Tomsk & Tomsk Pedagogical Inst.). Jun 19, 2018. 25 pp. 
Published in Phys.Rev. D98 (2018) no.2, 024013 
DOI: 10.1103/PhysRevD.98.024013

Link to the Russian news: https://lenta.ru/news/2018/07/25/cosmology
Other links in English: https://www.eurekalert.org/pub_releases/2018-07/kfu-pdo072518.php
https://scitechdaily.com/physicists-propose-possible-death-of-the-universe-scenario/


 
13
June 2018

SEWM 2018 - Strong and ElectroWeak Matter Conference


Congreso SEWM 2018 - Strong and ElectroWeak Matter Conference en Barcelona
Del 25 al 29 de junio se celebrará en las instalaciones de CosmoCaixa en Barcelona la decimotercera edición del congreso Strong and ElectroWeak Matter Conference (SEWM 2018) organizado por el Instituto de Ciencias del Espacio (ICE-CSIC), Institut d’Estudis Espacials de Catalunya (IEEC), Institut de Física d’Altes Energies (IFAE) y Institut de Ciències del Cosmos Universitat de Barcelona (ICCUB), con la colaboración de la Fundación Bancaria “La Caixa”.
 
En este marco, el Nobel de Física de 2017 Barry Barish dará una conferencia pública el día 26 a las 19:00 en las instalaciones de CosmoCaixa con el título Ondas gravitacionales: de Einstein a una nueva ciencia.
04
June 2018

The observation of the nova ASASSN-18fv by the ESA's INTEGRAL gamma-ray satellite, triggered by our team, has been selected as the Picture of the Month


The nova ASASSN-18fv is being observed with INTEGRAL, searching for the7Be line at 478 keV; the OMC light curve is the picture of the month
INTEGRAL/OMC optical observations of the bright nova ASASSN-18fv
Background image: An artist's rendering of a classical nova; credit (c) David A. Hardy/www.astroart.org
INTEGRAL/OMC optical observations of the bright nova ASASSN-18fv
  On 20 March a new bright transient optical source, near the Galactic plane, was found at V<10 mag by the All Sky Automated Survey for SuperNovae(ASAS-SN; ATel#11454). These observations showed an outburst amplitude of more than 7 mag. About a day later it was already brighter than 6 mag (see, e.g.,AAVSO Alert Notice 626). Early spectroscopy (ATels#11456,#11468) had not ruled out a Galactic classical nova, but the transient might also be a large outburst of a young stellar object or other peculiar explosion. Near-IR spectroscopy obtained about 10 days later (ATel#11506) showed that the spectrum is consistent with that observed for normal Fe II and transition (Fe II + He/N) class novae after peak. Two weeks later, Fermi/LAT and AGILE detected prolonged gamma-ray emission above ~100 MeV (ATels#11546,#11553), and a few days after that, NuSTAR in X-rays (3.5-78 keV; ATel#11608). If the source is indeed a classical nova, one may expect nucleosynthesis line emission from the decay of 7Be at 478 keV or of 22Na at 1275 keV, depending on the nova type. Since ASASSN-18fv looks like a CO nova, 7Be is favoured with respect to 22Na. This makes ASASSN-18fv a very interesting target for INTEGRAL.

On 23 April INTEGRAL started an out-of-TAC public observationof ASASSN-18fv. The source continued to be very bright (V~6.8 mag) one month after discovery, and it was, therefore, observed with the OMC in Fast monitoring mode. This is one of the few observations using this observing mode. With this mode, integrations of 3 seconds are performed at intervals of 4.5 seconds, and only the sections of the CCD containing the target of interest are read from the CCD and transmitted to ground. On 18 May, the OMC was configured back to Normal monitoring mode when the source brightness decayed to V~8.5 mag. Observations are currently still ongoing (see the INTEGRAL scheduling information).

The optical light curve as obtained by the AAVSO/visual estimates (open white circles) and with the INTEGRAL/OMC V-band (filled red circles) are shown in the main image. It can be seen that AAVSO data are important due to the large time span covered. The OMC data are of extremely good quality, although they are affected by time gaps produced when the source falls outside its FoV, because of the observing 5x5 dithering pattern. In the zoomed-in OMC light curve (inset figure top right) the excellent time resolution of the Fast monitoring mode and a photometric accuracy of about 0.02 mag can be seen (note that systematic effects not included). Short-scale time variability superposed on the general decline is clearly revealed. In some cases, the amplitude of the variability reaches 0.3 mag on timescales of several hours to one day. Due to the long INTEGRAL ToO program on ASASSN-18fv, the OMC is collecting a legacy optical data set on the source.

Oscillations were also reported in ATel#11508, around maximum light on timescales of days. According to the classification by Strope et al. (2010), ASASSN-18fv can be tentatively classified as a J-class nova. Light curves of this class are characterized by substantial jittering above the base level. The variations observed in the light curve could also resemble oscillations like those seen in the O-class. However, the observed variations by the OMC seem to be essentially random and start before the peak, while O-class novae are characterized by quasi-periodic oscillations which generally start around 3 mag below the peak. Future observations will help in the definitive classification of ASASSN-18fv.

Credits:Albert Domingo (INTEGRAL/OMC team, CAB/CSIC-INTA, Spain) and Margarita Hernanz (ICE-CSIC and IEEC, Spain).

We acknowledge with thanks the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this image.

Link to the original news in the ESA/INTEGRAL page.
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An institute of the Consejo Superior de Investigaciones Científicas

An institute of the Consejo Superior de Investigaciones Científicas
Affiliated with the Institut d'Estudis Espacials de Catalunya

Affiliated with the Institut d'Estudis Espacials de Catalunya