From sketch to painting: multiwavelength analysis of low-mass X-ray binaries

X-ray binaries are formed by a compact object (either a stellar-mass black hole or a neutron star) and a donor star, which transfers mass onto the former via an accretion disc. They are usually discovered thanks to their bright X-ray radiation, but observations at other wavelengths are mandatory to fully understand and characterise their extreme phenomenology. In this thesis, we present a multiwavelength observational study of five low mass X-ray binaries (LMXBs); a subclass defined by their late spectral type companion stars (< 1 Msun). The selected binaries contain both accreting neutron stars and black holes. We first study two recently discovered transient systems whose fundamental parameters are still under debate. The first is MAXI J1957+032, a recently discovered X-ray transient which has been detected in outburst 4 times in about 16 months, each outburst with equally short duration (< 5 days). These frequent and short outbursts (when compared with other transients), combined with the featureless spectrum that we obtained during the September 2016 event, suggest this may be a new short orbital period LMXB. In this thesis, we report on some of its main properties, such as the distance and luminosity. However, the nature of the compact star remains unknown. The second system, Swift J1357.2-0933, was discovered during an outburst in 2011 and classified as a LMXB harbouring a black hole. We obtained optical spectroscopy with GTC during quiescence, when the disc contribution to the optical flux is at its minimum. However, we did not find any trace of the donor star absorption features. Our spectroscopic analysis set new constraints on the non-stellar contribution to the optical flux, which allows us to estimate the distance and the height of the system above the Galactic plane. We also present a restrictive limit to the black hole mass (> 9.3 Msun). Therefore, Swift J1357.2-0933 is one of the most massive stellar-mass black holes ever found in our Galaxy, as well as a member of the new population of the thick disc, located >1 kpc outside the Galactic plane. Subsequently, we analysed two canonical binaries that harbour neutron stars with the aim to study their donor stars, which have never been detected before. Scorpius X-1 is the canonical persistent neutron-star LMXB. Despite it was discovered at the dawn of X-ray astronomy (more than 50 years ago), its persistent nature has prevented a proper dynamical study as it requires the detection of the donor star (only possible during the quiescence phase). We obtained near-infrared spectroscopy and performed a Monte Carlo analysis that allows us to set tighter constraints on the masses of this prototypical system. Aquila X-1 is also a canonical neutron-star LMXB, but in this case of the subtype of transient systems. It exhibits recurrent outbursts every two years, and has been exhaustively studied since its discovery more than 40 years ago. In spite of its accessible quiescent brightness (both in the optical and near-infrared), its dynamical study has been hampered so far by the presence of a brighter nearby (0.4 arcsec away) field star. Combining the integral field spectrograph SINFONI attached to the VLT telescope with its adaptive optics module, we singled out Aquila X-1 and obtained phase-resolved spectra. This allowed us to detect, for the first time, its donor star absorption features, as well as to measure its radial velocity curve. We set new constraints on the distance to the system, as well as the orbital inclination which discards high neutron star masses. To complete this sample, we also present the results of the most extensive optical spectroscopic campaign ever performed (to our knowledge) on an outburst of a transient X-ray binary system. V404 Cygni is a LMXB which contains a black hole. The system exhibits outbursts every 25 years. Its dynamical parameters have been measured and refined over the course of the last decades. Our new large database of 651 spectra covering the entire June 2015 outburst allows us to touch up the \textit{painting} of this transient. In particular, we detect continuous mass outflows from the accretion disc in the form of a cold wind (P-Cygni profiles), as well as an expanding nebula. Our study suggests that the outflow plays a major role in regulating the outburst evolution. Through the analysis of these five low mass X-ray binaries, this thesis provides new results on both their fundamental parameters and the relevant accretion-related physical processes at work. It also presents an extensive collection of the observational techniques employed along the different stages of the research process, that is, from the rough sketch of the system depicted by the initial detection in the X-rays, to a more detailed painting that detailed multiwavelength follow-up (both in outburst and quiescence) enables to elaborate

New records of Orchids from Morocco

The exploration of the Rif Valley (Morocco) during 2010 revealed the presence of some new taxa and records from Morocco. The new taxa are: Orchis langei subsp. magrebensis and Ophrys neglecta var. riphaea. Ophrys neglecta var. neglecta and Ophrys numida have been detected for the first time in Morocco

Spectroscopic monitoring of the candidate tidal disruption event in F01004-2237

We present results of spectroscopic monitoring observations of the Ultra-Luminous Infra Red Galaxy F01004-2237. This galaxy was observed to undergo changes in its optical spectrum, detected by comparing a spectrum from 2015 with one from 2000. These changes were coincident with photometric brightening. The main changes detected in the optical spectrum are enhanced He II $\lambda$4686 emission and the appearance of He I $\lambda$3898,$\lambda$5876 emission lines. The favoured interpretation of these changes was that of a tidal disruption event (TDE) happening in 2010. However, subsequent work suggested that these changes are caused by another hitherto unknown reason related to variations in the accretion rate in the active galactic nucleus (AGN). Our optical spectroscopic monitoring observations show that the evolution of the He lines is in line with the evolution seen in TDEs and opposite of what observed from reverberation mapping studies of AGNs, renewing the discussion on the interpretation of the flare as a TDE.Comment: 9 pages, 3 figures, 2 tables. Accepted for publication on ApJ on January 22, 202

Gymnocarpio dryopteridis-Abietion lasiocarpae nomen dubium et nomen ambiguum

Se propone una nueva clasificación para Gymnocarpio dryopteridis-Abietion lasiocarpa

New contributions on flora and vegetation of northeastern Portugal ultramafic outcrops

In this work we present some syntaxonomic novelties on the vegetation of the referred ultramafic outcrops focused on three new associations: Jonopsidio abulensis-Sedetum maireani, Armerio daveaui-Agrostietum castellanae and Seseli peixotoani- Avenuletum lusitanicae; in addition, a new nomenclatural combination of an endemic taxon from the Morais massif (Armeria langei subsp. marizii) is proposed. We also clarify the phytocoenotic structure of the Portuguese vegetation series through a simple diagrammatic representation, which is then applied to one unique climatophilous vegetation series present in the ultramafic rocks of northeastern Portugal: Genisto hystricis-Querco rotundifoliae Sigmetuminfo:eu-repo/semantics/publishedVersio

Rhododendro pontici-Prunion lusitanicae (Pruno-Lauretea azoricae) nomenclatural synonym of Osmundo-Alnion (Querco-Fagetea)

Se analiza la sinonimia entre Rhododendro pontici-Prunion lusitanicae (Pruno-Lauretea azoricae) y Osmundo-Alnion (Querco-Fagetea

Assessing the value of the information provision for enhancing the autonomy of mobility impaired users. Madrid pilot Site Study.

A City is the space where every person acquires the citizen condition, which demands access to multiple services and facilities, and develops social relations in a free and equal condition of options. A lack of accessibility limits independency and autonomy. Thus, the relationship between “sustainable development” and “accessibility for all” becomes clearer, and both goals reinforce each other. In this sense, information plays a key role in order to overcome existing barriers, specially for people who rarely use public transport, have impaired mobility, or make a particular journey for the first time. The impact and benefits is linked with public transport as a “facilitator” of mobility, and, in particular, for the aim of intermodality. The usefulness of information that should be provided (both the information itself and how is offered) to mobility impaired users (MI users) is discussed on this paper based on following of the ASK-IT project that has being carry out on Madrid. The work was done in close cooperation with representatives of all different types of MI user groups