Pere BlayUniversidad Internacional Valenciana | VIU
Pere Blay
Dr. in Physics
About
95
Publications
13,566
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Introduction
Pere Blay currently works at Valencian International University. His previous job was at Instituto de Astrofísica de Canarias as support astronomer at the Nordic Optical Telescope. Pere does research in Astrophysics, Astronomy and Observational Astronomy.
Additional affiliations
February 2018 - present
Valencian Internacional University
Position
- Lecturer
Description
- Senior Lecturer in Astronomy and Astrophysics Director of Cybersecurity Master Degree
May 2017 - February 2018
Universidad Internacional de Valencia
Position
- Lecturer
Description
- Máster Astronomia i Astrofísica: - Astronomía Óptica e Infraroja - Astrofísica de Altas Energías
Education
May 2006 - May 2006
September 1992 - July 1999
Publications
Publications (95)
The eROSITA instrument on board Spectrum-Roentgen-Gamma has completed four scans of the X-ray sky, leading to the detection of almost one million X-ray sources in eRASS1 only, including multiple new X-ray binary candidates. We report on analysis of the X-ray binary 1eRASS J085039.9-421151, using a ~55\,ks long NuSTAR observation, following its dete...
Context . Given the current era of big data in astronomy, machine-learning-based methods have begun to be applied over recent years to identify or classify objects, such as quasars, galaxies, and stars, from full-sky photometric surveys.
Aims . Here we systematically evaluate the performance of random forests (RFs) in classifying quasars using eith...
Context: Given the current big data era in Astronomy, machine learning based methods have being applied over the last years to identify or classify objects like quasars, galaxies and stars from full sky photometric surveys. Aims: Here we systematically evaluate the performance of Random Forests (RF) in classifying quasars using either magnitudes or...
Introduction
Addiction to video games is being studied mainly in adolescents, however, there are also
high prevalence rates in young adults. This problem may be aggravated by confinement by COVID-19. The objective was to establish changes in the problematic game to video games and addiction to them in young adult population (18-30 years) in Latin A...
There is a growing interest in the automated characterization of open clusters using data from the Gaia mission. This work evidences the importance of choosing an appropriate sampling radius (the radius of the circular region around the cluster used to extract the data) and the usefulness of additional multiband photometry in order to achieve accur...
There is a growing interest in the automated characterization of open clusters using data from the Gaia mission. This work evidences the importance of choosing an appropriate sampling radius (the radius of the circular region around the cluster used to extract the data) and the usefulness of additional multiband photometry in order to achieve accur...
(1) The goal of this study was to analyze the prevalence and pattern of alcohol consumption (frequency of consumption, average daily consumption, and risky consumption) before and during confinement due to the coronavirus disease (COVID-19) in the adult population and based on gender. (2) Methods: Data from 3779 individuals were collected via a set...
Impact of confinement measures on the Covid-19 pandemic on alcohol risk consumption Background: The public health strategies adopted for the containment of COVID-19 have generated psychosocial stressors that act as risk factors for alcohol consumption. The objectives of this study were to establish whether alcohol risk consumption varied during COV...
Objective:
The public health strategies adopted for the containment of COVID-19 have generated psychosocial stressors that act as risk factors for alcohol consumption. The objectives of this study were to establish whether alcohol risk consumption varied during COVID-19 confinement, and how these variations manifested as a function of different so...
We present an independent discovery and detailed characterisation of K2-280b, a transiting low density warm sub-Saturn in a 19.9-day moderately eccentric orbit (e = 0.35_{-0.04}^{+0.05}) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280b has a r...
We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = $0.35_{-0.04}^{+0.05}$ ) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has...
High mass X-ray binaries are among the brightest X-ray sources in the Milky Way, as well as in nearby Galaxies. Thanks to their highly variable emissions and complex phenomenology, they have attracted the interest of the high energy astrophysical community since the dawn of X-ray Astronomy. In more recent years, they have challenged our comprehensi...
We present an independent discovery and detailed characterisation of K2-280b, a transiting low density warm sub-Saturn in a 19.9-day moderately eccentric orbit (e = 0.35_{-0.04}^{+0.05}) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280b has a r...
PSR J2032+4127 is only the second known gamma-ray binary where it is confirmed that a young radio pulsar is in orbit around a Be-star. The interaction of the pulsar wind with the mass outflow from the companion leads to broad-band emission from radio up to TeV energies. In this paper we present results of optical monitoring of the 2017 periastron p...
PSRJ 2032+4127 is only the second known gamma-ray binary where it is confirmed that a young radio pulsar is in orbit around a Be-star. The interaction of the pulsar wind with the mass outflow from the companion leads to broad band emission from radio up to TeV energies. In the current paper we present results of optical monitoring of the 2017 peria...
High mass X-ray binaries are among the brightest X-ray sources in the Milky Way, as well as in nearby Galaxies. Thanks to their highly variable emissions and complex phenomenology, they have attracted the interest of the high energy astrophysical community since the dawn of X-ray Astronomy. In more recent years, they have challenged our comprehensi...
In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-ray binaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-...
The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (∼90 s), which included a detailed coverage of the most active phase of the event. We present a data base consisting of 651 optical spectra obtained...
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the...
The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained d...
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadr...
We report the discovery of three pulsating subdwarf B stars in binary systems observed with the Kepler space telescope during Campaign 5 of K2. EPIC 211696659 (SDSS J083603.98+155216.4) is a g-mode pulsator with a white dwarf companion and a binary period of 3.16 d. EPICs 211823779 (SDSS J082003.35+173914.2) and 211938328 (LB 378) are both p-mode p...
Massive stars, at least ∼10\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\sim10$\end{document} times more massive than the Sun, have two key properties that make them...
We present the results of our power spectral analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy gamma-rays, the Swift-XRT data in X-rays, several ground-based telescopes and the Kepler satellite in optical, and single-dish GHz-band radio telescopes. The multiwavelength light curves of the source are modeled in term...
The Be X-ray binary EXO 2030+375 was in an extended low luminosity state during most of 2016. We observed this state with NuSTAR and Swift, supported by INTEGRAL observations as well as optical spectroscopy with the NOT. We present a comprehensive spectral and timing analysis of these data here to study the accretion geometry and investigate a poss...
The Be X-ray binary pulsar EXO 2030+375, first detected in 1985, has shown a significant detected X-ray outburst at nearly every periastron passage of its 46-day orbit for the past ~25 years, with one low state accompanied by a torque reversal in the 1990s. In early 2015 the outbursts progressively became fainter and less regular while the monotoni...
HD3167 is a bright (V=8.9 mag) K0V star observed by the NASA's K2 space mission during its Campaign 8. It has been recently found to host two small transiting planets, namely, HD3167b, an ultra short period (0.96 d) super-Earth, and HD3167c, a mini-Neptune on a relatively long-period orbit (29.85 d). Here we present an intensive radial velocity fol...
Strong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor’s gravity and ionizing radiation can...
We analyse the light curve in the R band of the blazar OJ287, gathered during the 2015/2016 observing season. We did a search for quasi-periodic oscillations (QPOs) using several methods over a wide range of timescales. No statistically significant periods were found in the high-frequency domain both in the ground-based data and in Kepler observati...
The Be X-ray binary pulsar EXO 2030+375, first detected in 1985, has shown a significant detected X-ray outburst at nearly every periastron passage of its 46-day orbit for the past 25 years, with one low state accompanied by a torque reversal in the 1990s. In early 2015 the outbursts progressively became fainter and less regular while the monotonic...
The main goal of this work is to perform a detailed study of the optical variability of the Be/X-ray binary SAX J2239.3+6116. We obtained multi-colour BVRI photometry and polarimetry and 4000-7000 A spectroscopy. The optical counterpart to SAX J2239.3+6116 is a V=14.8 B0Ve star located at a distance of ~4.9 kpc. The interstellar reddening in the di...
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT wil...
Partida de Maitino, pol. 2 num. 163 (03206) Elche, Abstract: We analyse the light curve in the R-band gathered during the 2015/16 observing season of OJ287. We did a search for QPOs using several methods in wide time domain. No statistically significant periods were found in the high frequency domain both in the ground data and also in K2 observati...
We report a new subdwarf B pulsator, PG 1142-037, discovered during the first full-length campaign of K2, the two-gyro mission of the Kepler space telescope. 14 periodicities have been detected between 0.9 and 2.5 hr with amplitudes below 0.35 parts-per-thousand.
We have been able to associate all of the pulsations with low-degree, ℓ ≤ 2 modes. Fol...
OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R-ba...
This is a White Paper in support of the mission concept of the Large
Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We
discuss the potential of LOFT for the study of high-mass X-ray binaries and
ultra-luminous X-ray sources. For a summary, we refer to the paper.
Atmosphere-Space Interactions Monitor (ASIM) mission is an ESA payload which will be installed in the Columbus module of the International Space Station (ISS). ASIM is optimized to the observation and monitoring of luminescent phenomena in the upper atmosphere, the so called Transient Luminous Event (TLEs) and Terrestrial Gamma Ray Flashes (TGFs)....
This contribution gathers the contents of the white paper submitted by the UV community to the Call issued by the European Space Agency in March 2013, for the definition of the L2 and L3 missions in the ESA science program. We outlined the key science that a large UV facility would make possible and the instrumentation to be implemented.
The growt...
The Atmosphere-Space Interactions Monitor (ASIM) is an ESA mission which will be attached to the Columbus module of the International Space Station (ISS). The main goal of the ASIM mission is to characterize the optical and high-energy emission related to severe thunderstorms. We are setting up a set of simulations in order to analyse the expected...
The global Hands-on Universe association is producing and distributing
free resources world-wide to implement Inquire Based Scientific
Education (IBSE) at secondary and high school levels. The materials are
inspired in astronomical research and space exploration. The association
is implementing the Galileo Teacher Training Program world-wide. In th...
The INTEGRAL/IBIS/ISGRI instrument has detected this Be X-ray Binary system (BeXRB) very rarely during its 10 years of operations. However, all variability time scales of the source are covered by these observations: the pulse period of the spinning neutron star, orbital modulated outbursts, and one Type II outburst possibly related to a violent ma...
4U 2206+54 does not belong to any of the predefined classes of High Mass X-Ray Binary Systems (HMXRBs). It shows a mixture of behaviors between the wind-fed accretion systems with a supergiant optical companion, and those systems with a neutron star accreting from the disc of a main sequence Be star. The nature of the compact component to the syste...
The Be X-Ray Binary system X Per has been observed by INTEGRAL/IBIS/ISGRI repeatedly during its 10 years of operations. The source shows an interesting spectral and pulse-period variability in the high energy range which will be discussed in detail. A continuous spin-up of the source with sporadic sudden changes in pulse period are reported. The po...
2S 0114+650, GX 301-2, IGR J16358-4726, X Per, 4U 2206+54, SXP 1062, and 3A 1954+319 are thought to possess high magnetic fields. They have recently been named accreting magnetars, or highly magnetized accreting pulsars. In this work their properties are reviewed. Within the context of their observational properties (mainly from INTEGRAL data), and...
Ultraviolet astronomy is the astronomy of the void, of the vacuum; it is a precision tool that can detect the plasma threads or the subtle gas veils that shield some regions of the Universe.
Ultraviolet radiation creates life; it can trace the electromagnetic reverberation of the most luminous objects in the Cosmos and also enables us to study the...
The discovery of very slow pulsations (Pspin=5560s) has solved the
long-standing question of the nature of the compact object in the high-mass
X-ray binary 4U 2206+54 but has posed new ones. According to spin evolutionary
models in close binary systems, such slow pulsations require a neutron star
magnetic field strength larger that the quantum crit...
The space telescope World Space Observatory-Ultraviolet (WSO-UV) has a main design driver the development of a space facility that enables the ultraviolet observation of astronomical sources in the post-Hubble Space telescope era. WSO-UV is an international Russian led mission with a strong Spanish contribution that includes the ground segment and...
Supergiant Fast X-ray Transients have been recently unveiled as a new
class of High Mass X-ray Binaries thanks to the excellent survey
capabilities of the INTEGRAL/IBIS instrument. Although there is a
general agreement on explaining the behavior of supergiant Fast X-ray
Transients as the result of accretion by a compact object from the wind
of a su...
Here we give a brief outline of the activities developed during the
International Year of Astronomy specifically addressed to people with
various disabilities, both physical and/or intellectual. Among the
different activities that we carried out we wish to highlight the
publication of an astronomy book in Braille, astronomy talks for the
intellectu...
High Mass X-Ray Binary systems (HMXRB) are composed by a compact object orbiting around a OB massive star. The mass transfer
which takes place from the massive star onto its compact companion is the responsible of the emission of high energy photons
(X-rays) observed in these systems (to which they owe the name of their class). The presence of a co...
Our team has developed a variety of astronomical activities specifically
intended for people with special needs. In particular, we have created a
series of interactive talks, software with astronomical content,
hands-on activities, and a planetarium show, among others, to
communicate astronomy to people with different kinds of physical and
cognitiv...
The X-ray binary system 4U 2206+54 hides many mysteries. Among them, the
surprising behavior of both of its components: the O9.5 dwarf star
BD+53$^\circ$2790 and a slowly rotating neutron star. BD+53$^\circ$2790 misled
the astronomers showing itself very likely as a Be star. However, a deeper
spectral analysis and more intense monitoring, revealed...
The data provided by the ESA INTEGRAL mission have revealed the presence of a huge new population of HMXB sources. Among them, an important fraction belong to the fast-growing class of Supergiant Fast X-ray Transients (SFXT). We present a summary of our study to characterize the outburst frequency of SFXT using INTEGRAL data corresponding to our on...
SAX J2103.5+4545 is the Be/X-ray binary (BeX) with the shortest orbital period. It shows extended bright and faint X-ray states
that last for a few hundred days. The main objective of this work is to investigate the relationship between the X-ray and
optical variability and to characterize the spectral and timing properties of the bright and faint...
4U 2206+54 is one of the most intriguing X-Ray binaries. While showing properties closer to those of wind-fed supergiant X-Ray binaries, its optical counterpart lies in the main sequence, and recently it has been suggested that it may harbor an accretion disk (Finger et al. 2010). Only recently the real nature of the compact object has been reveale...
A detailed analysis of the BeX system 4U 0115+63 is presented. ISGRI data of the last two
bright outbusrts of the source (September, 2004 and April 2008) have been used. The overall behaviour of 4U 01156+63 is that of a typical transient BeX system. However, ISGRI data show very interesting timing properties, and tell a beautiful story about the on...
Public data of different types of High Mass X-Ray Binaries have been analyzed. We have developed a classification scheme based on their temporal variability and spectral properties. We find that the Be X-Ray binaries tend to show harder spectra than those of Supergiant X-ray Binaries and that the use of the statistical normalized variance seems to...
As we celebrate the International Year of Astronomy, we have been working on four different projects with the goal of making astronomy more accessible to people with special needs. These projects are 1) an astronomy book and web site for blind people, 2) an open source software for people with motor disabilities, 3) a planetarium program for the vi...
Context. The source 4U 2206+54 is one of the most enigmatic high-mass X-ray binaries. In spite of intensive searches, X-ray pul- sations have not been detected in the time range 10−3–103 s. A cyclotron line at ∼30 keV has been suggested by various authors but never detected with significance. The stellar wind of the optical companion is abnormally...
The eclipsing X-ray pulsar XTE J1855-026 (Corbet & Mukai 2002, ApJ
577, 923) has been unambiguously identified by a recent Swift
observation (Romano et al., ATel #1875) with the reddened early-type
star proposed as candidate counterpart by Verrecchia et al. (ATel #102).
High-quality spectra of the counterpart taken in August 2003 with the
4.2-m WHT...
An INTEGRAL long-term monitoring of XTE J1739-302, considered as the prototype source of the Supergiant Fast X-ray Transients (SFXTs), is presented in detail. The source follows a more complex behaviour than expected. Far from presenting a regular variability pattern, XTE J1739-3021 shows periods of high, intermediate, and low flaring activity. The...
BD+53 2790, an O9.5Vp star, is the optical counterpart to the HMXRB 4U 2206+54. This system was classified initially as a BeX, but observational evidence soon stressed the need to revise this classification. The permanent asymmetry in the H-alpha line profiles (in contrast with the cyclic variations shown by Be stars), the variations in the profile...
Context. In the past few years, a new class of high mass X-ray binaries (HMXRB) has been claimed to exist, the supergiant fast X-ray transients (SFXT). These are X-ray binary systems with a compact companion orbiting a supergiant star which show very short and bright outbursts in a series of activity periods overimposed on longer quiescent periods....
We have analyzed data from all the BeX systems observed by INTEGRAL up to revolution 620. In addition, public data from other types of High Mass X-Ray Binaries (HMXRBs) was analyzed, with the goal to compare the temporal and spectral behavior of the BeX systems to those of other types of HMXRBs. As a result we show a very extensive temporal and spe...