The first INTEGRAL-OMC catalogue of optically variable sources

The Optical Monitoring Camera (OMC) onboard INTEGRAL provides photometry in the Johnson V-band. With an aperture of 50 mm and a field of view of 5deg x 5deg, OMC is able to detect optical sources brighter than V~18, from a previously selected list of potential targets of interest. After more than nine years of observations, the OMC database contains light curves for more than 70000 sources (with more than 50 photometric points each). The objectives of this work have been to characterize the potential variability of the objects monitored by OMC, to identify periodic sources and to compute their periods, taking advantage of the stability and long monitoring time of the OMC. To detect potential variability, we have performed a chi-squared test, finding 5263 variable sources out of an initial sample of 6071 objects with good photometric quality and more than 300 data points each. We have studied the periodicity of these sources using a method based on the phase dispersion minimization technique, optimized to handle light curves with very different shapes.In this first catalogue of variable sources observed by OMC, we provide for each object the median of the visual magnitude, the magnitude at maximum and minimum brightness in the light curve during the window of observations, the period, when found, as well as the complete intrinsic and period-folded light curves, together with some additional ancillary data.Comment: Accepted by Astronomy & Astrophysics; 13 pages, 16 figures. Figures' resolution has been degraded to fit astro-ph constraint

Optical counterpart to Swift J0243.6+6124

Swift J0243.6+6124 was discovered during a giant X-ray outburst in October 2017. While there are numerous studies in the X-ray band, very little is known about the optical counterpart. We have performed an spectral and photometric analysis of the optical counterpart of this intriguing source. We find that the optical counterpart to Swift J0243.6+6124 is a V = 12.9, O9.5Ve star, located at a distance of $\sim5$ kpc. The optical extinction in the direction of the source is $A_V=3.6$ mag. The rotational velocity of the O-type star is 210 km s$^{-1}$. The long-term optical variability agrees with the growth and subsequent dissipation of the Be circumstellar disk after the giant X-ray outburst. The optical and X-ray luminosity are strongly correlated during the outburst, suggesting a common origin. We did not detect short-term periodic variability that could be associated with nonradial pulsations from the Be star photosphere.Comment: Wrong label in Fig 4 correcte

Wetlands in the south of Cordoba (Spain): conflicts between protected areas and surrounding rural lands

In the countryside of Cordoba, secular and intense agricultural space, certain endorheic wetlands of varied physical characteristics are located. In any case, several common features can be emphasized: landscape quality, ecological relevance (primarily aquatic birds) and the continuous interaction between ecosystems and the surrounding rural lands. This has justified the protection of the most outstanding wetlands, being declared as Nature Reserves. This paper sets out the main keys of the transition from agricultural area to protected area, and the grounds of the protection applied in order to achieve the desirable -and not always easy-compatibility between conservation and the proper deve/opment of traditional agricultural uses

El Sistema de Patrimonio Territorial y su significado en el contexto de las nuevas directrices de ordenación del territorio en Andalucía (España)

Comunicación presentada a UGI-2011. Regional Geographic Conference. Santiago de Chile, 2011El Plan de Ordenación del Territorio de Andalucía (POTA) aprobado en 2006 ha venido a impulsar un nuevo modelo con la intención de mejorar la integración económica y la cohesión social. Se pretende, en definitiva, fortalecer la articulación de esta región y, con tal fin, establece diversas estrategias de desarrollo territorial, entre las que ocupa un lugar destacado la creación del denominado “Sistema de Patrimonio Territorial de Andalucía” El SPTA procura una “gestión y ordenación unitaria” de los principales elementos que conforman el patrimonio natural y cultural de la región. Se intenta evitar una gestión del Patrimonio desde planteamientos parciales, considerando los bienes patrimoniales como elementos aislados sin conexión con el territorio y con otros bienes patrimoniales. Pero también existe otro factor que justifica el cambio de paradigma que se pretende con el SPTA: la necesidad de impulsar la puesta en valor de los bienes patrimoniales desde su entendimiento como un recurso que ha de repercutir en el desarrollo local y regional. A la reflexión sobre estas cuestiones se dedica este trabajo

Rapid spectral transition of the black hole binary V404 Cyg

During the June 2015 outburst of the black hole binary V404 Cyg, rapid changes in the X-ray brightness and spectra were common. The INTEGRAL monitoring campaign detected spectacular Eddington-limited X-ray flares, but also rapid variations at much lower flux levels. On 2015 June 21 at 20 h 50 min, the 3-10 keV JEM-X data as well as simultaneous optical data started to display a gradual brightening from one of these low-flux states. This was followed 15 min later by an order-of-magnitude increase of flux in the 20-40 keV IBIS/ISGRI light curve in just 15 s. The best-fitting model for both the pre- and post-transition spectra required a Compton-thick partially covering absorber. The absorber parameters remained constant, but the spectral slope varied significantly during the event, with the photon index decreasing from $\Gamma \approx 3.7$ to $\Gamma \approx 2.3$. We propose that the rapid 20-40 keV flux increase was either caused by a spectral state transition that was hidden from our direct view, or that there was a sudden reduction in the amount of Compton down-scattering of the primary X-ray emission in the disk outflow.Comment: 6 pages, 2 figures, accepted to A&

The Second INTEGRAL AGN Catalogue

The INTEGRAL mission provides a large data set for studying the hard X-ray properties of AGN and allows testing of the unified scheme for AGN. We present analysis of INTEGRAL IBIS/ISGRI, JEM-X, and OMC data for 199 AGN supposedly detected by INTEGRAL above 20 keV. The data analysed here allow a significant spectral extraction on 148 objects and an optical variability study of 57 AGN. The slopes of the hard X-ray spectra of Seyfert 1 and Seyfert~2 galaxies are found to be consistent within the uncertainties, whereas higher cut-off energies and lower luminosities are measured for the more absorbed / type 2 AGN. The intermediate Seyfert 1.5 objects exhibit hard X-ray spectra consistent with those of Seyfert 1. When applying a Compton reflection model, the underlying continua appear the same in Seyfert 1 and 2 with photon index 2, and the reflection strength is about R = 1, when assuming different inclination angles. A significant correlation is found between the hard X-ray and optical luminosity and the mass of the central black hole in the sense that the more luminous objects appear to be more massive. There is also a general trend toward the absorbed sources and type 2 AGN having lower Eddington ratios. The black holemass appears to form a fundamental plane together with the optical and X-ray luminosity of the form Lv being proportional to Lx^0.6 M^0.2, similar to that found between radio luminosity Lr, Lx, and M. The unified model for Seyfert galaxies seems to hold, showing in hard X-rays that the central engine is the same in Seyfert 1 and 2, but seen under different inclination angles and absorption. (Abridged)Comment: 26 pages, 16 figures, accepted for publication in A&A. Corrections by language editor included in version

Long-term optical and X-ray variability of the Be/X-ray binary H 1145-619: Discovery of an ongoing retrograde density wave

Context. Multiwavelength monitoring of Be/X-ray binaries is crucial to understand the mechanisms producing their outbursts. H 1145-619 is one of these systems, which has recently displayed X-ray activity

Rapid spectral transition of the black hole binary V404 Cygni

During the June 2015 outburst of the black hole binary V404 Cyg, rapid changes in the X-ray brightness and spectra were common. The INTEGRAL monitoring campaign detected spectacular Eddington-limited X-ray flares, but also rapid variations at much lower flux levels. On 2015 June 21 at 20 h 50 min, the 3-10 keV JEM-X data as well as simultaneous optical data started to display a gradual brightening from one of these low-flux states. This was followed 15 min later by an order-of-magnitude increase of flux in the 20-40 keV IBIS/ISGRI light curve in just 15 s. The best-fitting model for both the pre- and post-transition spectra required a Compton-thick partially covering absorber. The absorber parameters remained constant, but the spectral slope varied significantly during the event, with the photon index decreasing from Gamma approximate to 3.7 to Gamma approximate to 2.3. We propose that the rapid 20-40 keV flux increase was either caused by a spectral state transition that was hidden from our direct view, or that there was a sudden reduction in the amount of Compton down-scattering of the primary X-ray emission in the disk outflow

VLA monitoring of LS V +44 17 reveals scatter in the X-ray – radio correlation of Be/X-ray binaries

Funding: JvdE acknowledges a Warwick Astrophysics prize post-doctoral fellowship made possible thanks to a generous philanthropic donation, and was supported by a Lee Hysan Junior Research Fellowship awarded by St. Hilda’s College, Oxford, during part of this work. ARE is supported by the European Space Agency (ESA) Research Fellowship. TDR acknowledges support as an INAF IAF fellow. GRS is supported by NSERC Discovery Grant RGPIN-2021-0400.LS V +44 17 is a persistent Be/X-ray binary (BeXRB) that displayed a bright, double-peaked period of X-ray activity in late 2022/early 2023. We present a radio monitoring campaign of this outburst using the Very Large Array. Radio emission was detected, but only during the second, X-ray brightest, peak, where the radio emission followed the rise and decay of the X-ray outburst. LS V +44 17 is therefore the third neutron star BeXRB with a radio counterpart. Similar to the other two systems (Swift J0243.6+6124 and 1A 0535+262), its X-ray and radio luminosity are correlated: we measure a power law slope β = 1.25+0.64-0.30 and a radio luminosity of LR = (1.6 ± 0.2) × 1026 erg s-1 at a 0.5 − 10 keV X-ray luminosity of 2 × 1036 erg s-1 (i.e. ∼ 1 per cent LEdd). This correlation index is slightly steeper than measured for the other two sources, while its radio luminosity is higher. We discuss the origin of the radio emission, specifically in the context of jet launching. The enhanced radio brightness compared to the other two BeXRBs is the first evidence of scatter in the giant BeXRB outburst X-ray – radio correlation, similar to the scatter observed in sub-classes of low-mass X-ray binaries. While a universal explanation for such scatter is not known, we explore several options: we conclude that the three sources do not follow proposed scalings between jet power and neutron star spin or magnetic field, and instead briefly explore the effects that ambient stellar wind density may have on BeXRB jet luminosity.Publisher PDFPeer reviewe