Astrofísica Robótica y de Altas Energías (ARAE) – TRACK RECORD

 

The ARAE research group (http://arae.iaa.es, ICT-189 amongst the information technology groups) was founded in 2001, although some of its members have already started their activity in 1990, and belongs to the Andalusian Research Plan (PAI) based in the Institute of Astrofísica de Andalucía (IAA) of the National Research Council (CSIC) in Granada.

 

A dozen of members, including scientists, engineers and ITs are working on a variety of projects, combining their strengths. Half of the members are foreigners from all over the world, what it is also an added value.

 

Research areas are multi-range observations of high-energy phenomena, theoretical stellar evolutionary models and models of stellar population synthesis. Significant technological developments are also carried out, regarding the robotization of small/medium size observatories and astronomical instrumentation development (ground-based and space-borne). Public outreach and citizen science is also part of the ARAE activities in the recent years.

 

1. AREAS OF RESEARCH

These are: Meteoroids, compact objects (X-ray Binaries), cosmic gamma-ray bursts (GRBs), Gravitational Waves (GWs), Astrophysical Transients (eg. OTs), Theoretical Stellar Evolutionary Models and Stellar Population Synthesis models.

 

1.1. X-ray binaries

The study of X-ray binaries (XRBs) already started in 1990, with the analysis and interpretation of data from the WATCH instrument on board the Granat satellite. Special attention has been devoted to GRO J0422 +32 (X-ray Nova Persei 1992) and GRS 1915 +105. For the first one we discover its optical counterpart, and we tested that it houses probably a black hole. Furthermore, we also observed for the first time in this type of objects, a secondary explosion in 1993. With respect to the second object, GRS 1915+105, discovered by us (Castro-Tirado et al. 1992, IAUC 5590), it has become the first observed microquasar in the galaxy, according to radio observations which revealed the superluminal motion. We identified the infrared counterpart, and for the first time observed emission lines in the K band IR, presumably originating in the accretion disk around the central black hole. Multi-range observations have been made in other binary systems (XTE J0929-29, XTE J1550-54, XTE J1650-500, XTE J1859+28, V404 Cyg).

 

1.2. Gamma-ray bursts

Gamma-ray bursts (GRBs) are one of the most important research field in high energy astrophysics. These explosions were initially studied by us using the WATCH data. In order to identify the counterparties, we extended the search to other wavelengths, in particular X bands (with Rosat, BeppoSAX), UV end (with EUVE), optical (several ground-based telescopes and HST), infrared (different telescopes ground and ISO) and submillimeter and radio (Plateau de Bure Interferometer).

 

Important results were achieved in 1997, in close collaboration with the BeppoSAX satellite scientific group dedicated to the study of GRBs. For the specific case of GRB 970508, the first images were obtained only 4-5-hours after the explosion-gamma, which showed the optical counterpart, being the object observed with HST and the Plateau de Bure Interferometer, and the Infrared Space Observatory. Other important findings were the possible supernova underlying to GRB 980326, the first evidence of a collimated jet emission (GRB 990123), and the indisputable relationship between the highly energetic SN 2003 dh and GRB 030329, the finding of starburst galaxies hosting several GRBs (GRB 051022). And during the Swift satellite Era, it is worth to mention the study of the first precisely locate short-duration GRB 050509, the study of the ultra-high z GRBs (eg GRB 090423) and the afterglow spectrum study for GRB 130603B (at z = 0.35) and GRB 130606A (at z = 5.91, discovered by BOOTES-2/TELMA). We are also continuing performing multiwavelength studies with optical observatories (BOOTES network, OSN, CAHA, GTC) and satellites (XMM-Newton, Chandra and INTEGRAL).

 

1.3. Gravitational Waves

A gravitational-wave (GW) transient was identified in the electromagnetic spectrum in 2017 for the first time. The event, was recorded by the LIGO detectors on 2017 Aug 17. This event (GW170817) was identified at other wavelengths with ground- and space-based facilities. We provided the only image gathered by a Spanish facility (the Javier Gorosabel Telescope at our BOOTES-5 station in Mexico (Abbott et al. 2017, ApJ 848, L12). Additional spectroscopic observations by a team of astronomers at ESO (including some of us) confirmed the existence of a macronova and the production of heavier then Fe elements by means of the r-process nucleosynthesis in a double neutron-star merger (Pian et al. 2017, Nat 551, 67). We also study the short-duration gamma-ray burst GRB 170817A associated to it and concluded that this is an event originated from an strutuctured jet at a large viewing angle (Zhang et al. 2018, Nat Co. 9, 447).

 

1.4. Astrophysical Transients

It is questionable whether any of these wide category (like Optical Transients, OT) may be related to GRBs or not. In any case, we are also pursuing this research, as some of these objects seem to be related with exceptional active stars, tidal disruption events (TDFs) and quasars, amongst others. For instance, cbservations of DG CVn by the Swift satellite and several ground-based observatories during its superflare event on 2014 allowed us to perform a complete hard X-ray-optical follow-up of a superflare from the red-dwarf star. The observations support the fact that the superflare can be explained by the presence of (a) large active region(s) on the surface of the star (Caballero-García et al. 2015, MNRAS 452, 4195).

 

1.5. Theoretical stellar evolutionary models including apsidal motion and tidal evolution, gravity and limb-darkening, compact objects (white dwarfs, neutron stars, black holes) and irradiated stars. Convective core overshooting has a strong influence on the evolution of stars of moderate and high mass. Studies of double-lined eclipsing binaries and stellar oscillations have renewed interest in the possible dependence of overshooting on stellar mass, which has been poorly constrained by observations so far. Here, we have used a sample of 29 well-studied double-lined eclipsing binaries in key locations of the H-R diagram to infer an approximate relationship between the the classical overshooting parameter αov and the coefficient fov such as αov/fov = 11.36 +/- 0.22 (Claret and Torres 2017, ApJ 849, 18).

 

1.6. Models of stellar population synthesis

Some team members have developed models of stellar population synthesis covering the emission due to stellar evolution from radio gamma rays. Such synthesis models were used to predict the gamma-ray galactic emission due to the decay of radioactive isotopes such as Al-26 or Fe-60, predictions to be tested with data from the INTEGRAL satellite. The models also allows to derive the X-ray emission from star-forming galaxies and theoretical correlations between different energy ranges. These models are also able to predict the rate of supernovae and, in the near future, the populations of X-ray binaries in star-forming regions.

 

 

The ARAE group at IAA-CSIC has pioneered in Spain the research in the GRB field, since the 1990’s. With over 250 per-reviewed publications in this regard, including 4 in Science and 7 in Nature and more than 300 GCN Circulars, the group leads opportunity programs in all national facilities and participated in space missions at co-I level (INTEGRAL, Lomonosov). In THESSEUS we are leading the Spanish participation.

 

 

2. INSTRUMENTAL AND TECHNOLOGICAL DEVELOPMENTS

 

2.1. BOOTES GLOBAL NETWORK OF ROBOTIC TELESCOPES

BOOTES (English Burst Observer and Optical Transient Exploring System) is a Global Network of Robotic Telescopes. The first ever robotic observatory in Spain (BOOTES-1) was deployed in 1998. Nowadays, there are two stations in Spain and another two abroad. The first Spanish station (BOOTES-1) is located at El Arenosillo (CEDEA-INTA) in Mazagón (Huelva) and the second one (BOOTES-2) was deployed at the Experimental Station of La Mayora (EELM-CSIC) in Algarrobo Costa (Málaga), opened in 2001. The two stations abroad are BOOTES-3 (Blenheim/Lauder, New Zealand, 2009), BOOTES-4 (Lijiang, China, 2012) and BOOTES-5 (San Pedro Mártir, Mexico, 2015). The dome design, improved over the years, was recognized as a patent in 2007.

 

The main BOOTES scientific goal is the simultaneous observation of GRBs and the study of astrophysical transients. With the exception of the BOOTES-1 instrumentation, the rest of BOOTES stations host a fast slewing 60cm RC telescope, with a EMCCD camera at the Cassegrain focus providing a 10’ x 10’ FOV. Among the most spectacular results obtained to date, highlights the discovery of the optical afterglow to GRB 130606A, at a redshift of 5.91, when the Universe was only about 1 billion years old (http://bootes.iaa.es).

 

2.2. PI-OF-THE-SKY NORTH

The ARAE group is also making fully robotic the T60 (0.6m diameter) telescope at Observatorio de Sierra Nevada in Granada, and it is becoming the first robotic near-IR telescope in Europe, when the BIRCAM near-IR camera is attached. It is not just the ability to do first-rate science which has led to the creation of the consortium, but the possibility to train technologists in the field of IR instrumentation, control of robotics and telematics (more on bootes-ir.iaa.es). When no GRB alerts will be followed-up, additional near-IR in other fields (from Solar System to Extragalactic Astronomy) will be attempted, as part of the diverse scientific fields pursued by the different IAA groups.

 

2.3. OTHER GROUND-BASED PROJECTS

Regarding optical instrumentation, several of the team members have extensive experience in the development of optical instrumentation. We developed an all-sky optical camera to record the entire sky every minute (CASSANDRA) patented and licensed to a Spanish company, which installed similar devices in other parts of the country. We also developed a low-resolution spectrograph (COLORES) for the TEMA 0.6m at the BOOTES-2 station (patented in 2011). Other initiatives that have been undertaken are: 1) a near-IR camera for the 0.6m telescope at Observatorio de Sierra Nevada; and 2) a full Stockes polarimeter (EDIPO) for a 1.5m class telescope.

 

2.4. SPACE-BORNE INSTRUMENTATION

With respect to space instrumentation, we have participated in the satellites GRANAT (international mission led by the Russian Space Agency) and INTEGRAL (led by ESA). Nowadays we participate in the instrument UBAT / UFFO-p (http://uffo.skku.kr) launched into space aboard the Lomonosov spacecraft in 2016. In THESEUS (a M5 mission selected for study phase by ESA) we are leading the Spanish contribution.

 

3.PATENTS

As result of technological development, three patents have been granted to some of the team members:

-a novel large format all-sky CCD camera (2005)

-a double roof automatic enclosure for hosting the robotic instrumentation (2008)

-a low-resolution spectrograph for robotic telescopes (2011)

 

4. PUBLIC OUTREACH AND CITIZEN SCIENCE

Public outreach is most essential for ARAE and many of the ARAE scientists write in journals for the general public, give regularly public talks and some of the research results attract press media and so on.

4.1. GLORIA. Some ARAE group members were involved in the GLORIA (GLObal Robotic Infrared Array for e-Science) FP-7 EU Project, which provided Internet users the possibility to study the night sky every day. GLORIA (http://gloria-project.eu) is fulfilling the challenge of building the first free-access telescope network, that will allow any user to produce scientific knowledge. The project, that started in October of 2011, allotted in direct, real-time, observation mode of three telescopes located in Spain (Huelva, Málaga and Tenerife), one in Czech Republic and another in New Zealand.

The project was based on the philosophy of collective intelligence: when more eyes are looking at the sky, more can be learnt from it. The users were able to perform research based on the proposed experiments, which included the analysis of Solar activity and the detection and characterization of asteroids and supernovae, amongst others, or even propose their own research topics. And they were able to do it either by scheduling observations and requesting telescope time or by using GLORIA's database or that of the European Virtual Observatory.

The network also offered the free software and methodology for advanced users to robotise their own telescopes and connect them to the network, so that a great number of telescopes were grouped in only one website.

Lastly, the project made particular emphasis in outreach and is developing activities to awaken the interest in astronomy, particularly among young people. Already GLORIA provided live transmission of astronomical events such as the Venus transit in 2012, the total Solar eclipse of 2013 and the total Lunar eclipse of April 15 2014 from different locations including Tenerife (Spain) and Cuzco (Peru).

GLORIA was a three year project financed by the Seventh Framework Programme of the European Union (FP7/2007-2012) with reference number 283783. The project, beginning in October 2011, involved thirteen institutions from eight countries and was co-lead by the ARAE Principal Investigator.

 

4.2. PIIISA. Some ARAE group members are currently involved in a project in which high school students are getting acquainted with science and using the BOOTES robotic telescopes for reaserch in a given project.

 

Carta a Javier Gorosabel de Alberto J. Castro-Tirado 

 

Despedida a Javier Gorosabel del IAA