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Los trascendentales cambios operados durante la Gran Guerra en el arte militar despertaron el interés de los militares españoles. Pero a pesar de las ansias de reforma de militares y políticos de la época, poco se hizo al acabar la contienda para mejorar la organización de un ejército que mantenía una estructura más propia del siglo xix. En suma, la necesaria reforma técnica que precisaba siguió sin realizarse plenamente, algo que se mantuvo durante la dictadura de Primo de Rivera y la República, aunque ya durante esta se observa un intento de diversificación en su organización. ; The transcendental changes wrought during the Great War in military art aroused the interest of the Spanish military. But despite the eagerness to reform the military and politicians of the time, little was done at the end of the struggle to improve the organization of an army that maintained a structure more typical of the nineteenth century. In sum, the necessary technical reform was still not fully implemented, something that continued during the dictatorship of Primo de Rivera and the Republic, although during this time there was an attempt to diversify its organization.

Esta investigación se centra en el efecto de dos dispositivos narrativos que pueden mejorar la eficacia de narraciones eudaimónicas elaboradas para disminuir el prejuicio hacia menores migrantes no acompañados en España. Se analiza si incrementar la similitud en términos de identidad social con el personaje y narrar la historia en primera persona desencadenan mecanismos relevantes (identificación y elaboración cognitiva) para mejorar las actitudes intergrupales y estimular una conducta prosocial. Los resultados del experimento en línea (N = 491) revelaron un efecto indirecto de la similitud en términos de identidad social en las variables dependientes a través de la similitud percibida (mediador primario), la identificación (mediador secundario) y la elaboración cognitiva (mediador terciario). La voz narrativa también tuvo un efecto indirecto sobre las variables dependientes mediado por la identificación (mediador primario) y la elaboración cognitiva (mediador secundario). Se concluye que determinados dispositivos narrativos pueden potenciar procesos afectivos y cognitivos que explican la eficacia de mensajes testimoniales diseñados para reducir el racismo y la xenofobia.

Se analiza el efecto del contacto imaginado y de la similitud con el protagonista de una narración corta escrita en primera persona cuya meta era la mejora de las actitudes hacia inmigrantes estigmatizados. Método: Los participantes del experimento (N = 400) recibieron instrucciones de contacto intergrupal imaginado (versus instrucciones de control) inmediatamente antes de leer una narración en primera persona protagonizada por un inmigrante de origen marroquí con alta o baja similitud con la audiencia. Después de leer la narración cumplimentaron un cuestionario con las variables dependientes. Resultados: Se observó que la condición óptima de recepción, inducía una mayor identificación y transporte narrativo que la condición de control, lo que provocaba a su vez un mayor deseo de compartir el mensaje través de las redes sociales. Conclusiones: Se discuten los resultados en el contexto de la investigación sobre persuasión narrativa y reducción del prejuicio.

El principal objetivo de la presente investigación fue generar nuevo conocimiento en torno a los procesos de persuasión narrativa y su aplicación para reducir el prejuicio hacia inmigrantes altamente estigmatizados. Se analizó el efecto de la similitud entre el protagonista de una narración diseñada para reducir el prejuicio y la audiencia del mensaje en la identificación con el protagonista y en las actitudes hacia la inmigración. Para ello se llevó a cabo una investigación experimental en la que participaron 90 estudiantes de universidad. Como estímulos experimentales se utilizaron narraciones cortas escritas en primera persona que relataban la experiencia migratoria de un inmigrante estigmatizado. Los participantes fueron asignados aleatoriamente a dos condiciones experimentales diseñadas en función de cómo aparecía caracterizado el protagonista de la narración. Los resultados mostraron que la similitud influía positivamente en la identificación con el protagonista lo que se asociaba, a su vez, a actitudes más favorables hacia la inmigración. La investigación realizada abre una línea de estudio sobre los factores vinculados con la construcción de los personajes y de los mensajes narrativos, y su incidencia en procesos de recepción (identificación, enganche narrativo), e indirectamente, en variables vinculadas con el cambio social y la promoción de la tolerancia.

e present the first 3D radiation-hydrodynamic simulations on the formation and evolution of born-again planetary nebulae (PNe), with particular emphasis to the case of HuBi 1, the inside-out PN. We use the extensively tested GUACHO code to simulate the formation of HuBi 1 adopting mass-loss and stellar wind terminal velocity estimates obtained from observations presented by our group. We found that, if the inner shell of HuBi 1 was formed by an explosive very late thermal pulse (VLTP) ejecting material with velocities of ∼300 km s−1, the age of this structure is consistent with that of ≃200 yr derived from multi-epoch narrow-band imaging. Our simulations predict that, as a consequence of the dramatic reduction of the stellar wind velocity and photon ionizing flux during the VLTP, the velocity and pressure structure of the outer H-rich nebula are affected creating turbulent ionized structures surrounding the inner shell. These are indeed detected in Gran Telescopio Canarias MEGARA optical observations. Furthermore, we demonstrate that the current relatively low ionizing photon flux from the central star of HuBi 1 is not able to completely ionize the inner shell, which favours previous suggestions that its excitation is dominated by shocks. Our simulations suggest that the kinetic energy of the H-poor ejecta of HuBi 1 is at least 30 times that of the clumps and filaments in the evolved born-again PNe A 30 and A 78, making it a truly unique VLTP event. © 2021 The Author(s). ; JAT thanks funding by Fundación Marcos Moshinsky (Mexico) and the Direcciónn General de Asuntos del Personal Académico (DGAPA) of the Universidad Nacional Autónoma de México (UNAM) project IA100720. VL gratefully acknowledges support from the CONACYT Research Fellowship program. BMM and MAG acknowledge support of the Spanish Ministerio de Ciencia, Innovación y Universidades (MCIU) grant PGC2018-102184-B-I00. AE acknowledges support from DGAPA-PAPIIT (UNAM) grant IN 109518. This work has made extensive use of NASA's Astrophysics Data System. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. ; The INT Photometric Hα Survey (IPHAS) has provided us with a number of new emission-line sources, among which planetary nebulae (PNe) constitute an important fraction. Here we present a detailed analysis of the IPHAS nebula Sab 19 (IPHASX J055242.8+262116) based on radio, infrared, and optical images and intermediate- and high-dispersion long-slit spectra. Sab 19 consists of a roundish 0.10 pc in radius double-shell nebula surrounded by a much larger 2.8 pc in radius external shell with a prominent H-shaped filament. We confirm the nature of the main nebula as a PN whose sub-solar N/O ratio abundances, low ionized mass, peculiar radial velocity, and low-mass central star allow us to catalogue it as a Type III PN. Apparently, the progenitor star of Sab 19 became a PN when crossing the Perseus Arm during a brief visit of a few Myr. The higher N/O ratio and velocity shift ≃ 40 km s-1 of the external shell with respect to the main nebula and its large ionized mass suggest that it is not truly associated with Sab 19, but it is rather dominated by a Strömgren zone in the interstellar medium ionized by the PN central star. © The Author(s) 2020. Published by Oxford University Press on behalf of The Royal Astronomical Society. ; We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). MAG acknowledges support from the Spanish Government Ministerio de Ciencia, Innovacion y Universidades (MCIU) through grant PGC2018-102184-B-I00, LS acknowledges support from DGAPA, UNAM PAPIIT project IN101819, GR-L acknowledges support from Consejo Nacional de Ciencia y Tecnologia (CONACyT) grant 263373 and Programa para el Desarrollo Profesional (PRODEP) Mexico, and EJA acknowledges support from MCIU grant PGC2018-095049-B-C21. MAG and EJA are supported by the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). This research has made use of the SIMBAD database operated at CDS (Strasbourg, France), the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology, the NASA's Astrophysics Data System, and NRAO VLA Sky Survey. It has also made use of data obtained as part of the INT Photometric Ha Survey (IPHAS) of the Northern Galactic Plane carried out at the Isaac Newton Telescope (INT), which is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrof ' isica de Canarias. All IPHAS data are processed by the Cambridge Astronomical Survey Unit, at the Institute of Astronomy in Cambridge. Based on observations made with the Nordic Optical Telescope (NOT) and Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. NOT is owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University. This work is partly based on data obtained with the instruments ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA, and OSIRIS, built by a Consortium led by the Instituto de Astrofisica de Canarias in collaboration with the Instituto de Astronomia of the Universidad Autonoma de México. OSIRIS was funded by GRANTECAN and the National Plan of Astronomy and Astrophysics of the Spanish Government. ; Peer reviewed

Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. ; The guest star of AD 1181 is the only historical supernova of the past millennium that is without a definite counterpart. The previously proposed association with supernova remnant G130.7+3.1 (3C 58) is in strong doubt because of the inferred age of this remnant. Here we report a new identification of SN 1181 with our codiscovery of the hottest known Wolf-Rayet star of the oxygen sequence (IRAS 00500+6713 or 2MASS J00531123+6730023, here named by us as "Parker's star") and its surrounding nebula Pa 30. Our spectroscopy of the nebula shows a fast shock with extreme velocities of ≈1100 km s-1. The derived expansion age of the nebula implies an explosive event ≈1000 yr ago that agrees with the 1181 event. The on-sky location also fits the historical Chinese and Japanese reports of SN 1181 to within 3.°5. Pa 30 and Parker's star have previously been proposed to be the result of a double-degenerate merger, leading to a rare Type Iax supernova. The likely historical magnitude and the distance suggest the event was subluminous for normal supernova. This agrees with the proposed Type Iax association that would also be only the second of its kind in the Galaxy. Taken together, the age, location, event magnitude, and duration elevate Pa 30 to prime position as the counterpart of SN 1181. This source is the only Type Iax supernova where detailed studies of the remnant star and nebula are possible. It provides strong observational support for the double-degenerate merger scenario for Type Iax supernovae. © 2021. The Author(s). Published by the American Astronomical Society. ; Q.A.P. thanks the Hong Kong Research Grants Council for GRF research support under grants 17326116 and 17300417. A.R. and F.L. thank HKU for the provision of postdoctoral fellowships under Q.A.P., while F.L. also acknowledges funding from MTA Hungary (OTKA project No. K-132406). A.A.Z. thanks the Hung Hing Ying Foundation for the provision of a visiting professorship at HKU and acknowledges funding from the UK STFC under grant ST/T000414/1. M.A.G. was funded under grant number PGC2018-102184-B-I00 of the Ministerio de Educación, Innovación y Universidades cofunded with FEDER funds. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

The parallax expansion and kinematics of a nova shell can be used to assess its age and distance, and to investigate the interaction of the ejecta with the circumstellar medium. These are key to understand the expansion and dispersal of the nova ejecta in the Galaxy. Multi-epoch images and high-dispersion spectroscopic observations of the recently discovered classical nova shell IPHASX J210204.7 + 471015 around a nova-like system have been used to derive a present-day expansion rate of 0 ''. 100 yr(-1) and an expansion velocity of 285 km s(-1). These data are combined to obtain a distance of 600 pc to the nova. The secular expansion of the nova shell place the event sometime between 1850 and 1890, yet it seems to have been missed at that time. Despite its young age, 130-170 yr, we found indications that the ejecta has already experienced a noticeable deceleration, indicating the interaction of this young nova shell with the surrounding medium.© 2019 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society ; ES acknowledges support from Universidad de Guadalajara and Consejo Nacional de Ciencia y Tecnologia (CONACyT). MAG acknowledges support of the grant AYA2014-57280-P, cofunded with Fondo Europeo para el Desarrollo Regional (FEDER) funds. GR-L acknowledges support from Fundacion Marcos Moshinsky, CONACyT, and Programa para el Desarrollo Profesional Docente (PRODEP) (Mexico). LS acknowledges support from Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) grant IA-101316 (Mexico). JAT and MAG are funded by Universidad Nacional Autonoma de Mexico (UNAM), Direccion General de Asuntos del Personal Academico (DGAPA) PAPIIT project IA100318. We thank Martin Henze for his advise on historical records of novae and photographic plates. This paper also makes use of data obtained as part of the INT Photometric H alpha Survey of the Northern Galactic Plane (IPHAS: http://www.iphas.org) carried out at the Isaac Newton Telescope (INT). The INT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio delRoque de los Muchachos of the Instituto de Astrofisica de Canarias. All IPHAS data are processed by the Cambridge Astronomical Survey Unit at the Institute of Astronomy in Cambridge. The band-merged DR2 catalogue was assembled at the Centre for Astrophysics Research, University of Hertfordshire, supported by STFC grant ST/J001333/1. The Digitized Sky Surveys were produced at the Space Telescope Science Institute (STScI) under US Government grant NAGW-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. The National Geographic Society-Palomar Observatory Sky Atlas (POSS-I) was made by the California Institute of Technology with grants from the National Geographic Society. The second Palomar Observatory Sky Atlas (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. The Oschin Schmidt Telescope is operated by the California Institute of Technology and Palomar Observatory. The UK Schmidt Telescope was operated by the Royal Observatory, Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. Supplemental funding for sky-survey work at the STScI is provided by the European Southern Observatory. This work made use of the HDAP which was produced at Landessternwarte Heidelberg-Konigstuhl under grant no. 00.071.2005 of the Klaus-Tschira-Foundation.

SXP 1062 is a Be X-ray binary (BeXB) located in the Small Magellanic Cloud. It hosts a longperiodX- ray pulsar and is likely associated with the supernova remnant MCSNRJ0127-7332. In this work we present a multiwavelength view on SXP 1062 in different luminosity regimes. We consider monitoring campaigns in optical (OGLE survey) and X-ray (Swift telescope). During these campaigns a tight coincidence of X-ray and optical outbursts is observed. We interpret this as typical Type I outbursts as often detected in BeXBs at periastron passage of the neutron star (NS). To study different X-ray luminosity regimes in depth, during the source quiescence we observed it with XMM-Newton while Chandra observations followed an X-ray outburst. Nearly simultaneously with Chandra observations in X-rays, in optical the RSS/SALT telescope obtained spectra of SXP 1062. On the basis of our multiwavelength campaign we propose a simple scenario where the disc of the Be star is observed face-on, while the orbit of the NS is inclined with respect to the disc. According to the model of quasi-spherical settling accretion our estimation of the magnetic field of the pulsar in SXP 1062 does not require an extremely strong magnetic field at the present time.© 2018 The Author(s). ; AGG and LMO are supported by the Deutsches Zentrum fur Luft und Raumfahrt (DLR) grants FKZ 50 OR 1404 and FKZ 50 OR 1508. LMO acknowledging partial support by the Russian Government Program of Competitive Growth of Kazan Federal University. MK acknowledges funding by the Bundesministerium fur Wirtschaft und Technologie under Deutsches Zentrum fur Luft- und Raumfahrt grants 50 OR 1113 and 50 OR 1207. SBP is supported by the Russian Science Foundation grant 14-12-00146. MPES received funding through the Claude Leon Foundation Postdoctoral Fellowship program and the National Research Foundation. ; Peer Reviewed

We present the first detailed study of the bipolar planetary nebula (PN) IPHASX J191104.8+060845 (PN G 040.6-01.5) discovered as part of the Isaac Newton Telescope Photometric Hα Survey of the Northern Galactic plane (IPHAS). We present Nordic Optical Telescope narrow-band images to unveil its true morphology. This PN consists of a main cavity with two newly uncovered extended low-surface brightness lobes located towards the NW and SE directions. Using near-IR WISE images we unveiled the presence of a barrel-like structure, which surrounds the main cavity, which would explain the dark lane towards the equatorial regions. We also use Gran Telescopio de Canarias spectra to study the physical properties of this PN. We emphasize the potential of old PNe detected in IPHAS to study the final stages of the evolution of the circumstellar medium around solar-like stars. © 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society ; The authors are thankful to the referee for a prompt report that improved the presentation of this paper. JBJ-G and JAT are funded by UNAM DGAPA PAPIIT projects IA100318 and IA100720. JBJ-G and LS are funded by UNAM-PAPIIT grant IN101819. SZ works under the collaboration agreement 'UNAM-TecNM 433103020-30-IX-15'. GR-L acknowledges support from CONACYT grant 263373 and PRODEP (Mexico). MAG acknowledges support from the Spanish Government Ministerio de Ciencia, Innovacion y Universidades through grant PGC2018-102184-B-I00. QAP thanks the Hong Kong Research Grants Council for GRF research support under grants 17326116 and 17300417. We thank the daytime and night support staff at the OAN-SPM for facilitating and helping obtain our observations. This paper makes use of data obtained as part of the INT Photometric Ha Survey of the Northern Galactic Plane (IPHAS) carried out at the Isaac Newton Telescope (INT). The INT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. All IPHAS data are processed by the Cambridge Astronomical Survey Unit, at the Institute of Astronomy in Cambridge. Based on observations collected at the Observatorio Astronomico Nacional at San Pedro Martir, B.C., Mexico. Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. Based on observations made with the Gran Telescopio Canarias (GTC), installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

We present a multiwavelength characterization of the planetary nebula (PN) NGC 6905 and its [Wolf–Rayet]-type ([WR]) central star (CSPN) HD 193949. Our Nordic Optical Telescope Alhambra Faint Object Spectrograph and Camera (ALFOSC) spectra and images unveil in unprecedented detail the high-ionization structure of NGC 6905. The high-quality spectra of HD 193949 allowed us to detect more than 20 WR features including the characteristic O-bump, blue bump, and red bump, which suggests a spectral type no later than a [WO2]-subtype. Moreover we detect the Ne VII and Ne VIII broad emission lines, rendering HD 193949 yet another CSPN with Teff ≲ 150 kK exhibiting such stellar emission lines. We studied the physical properties (Te and ne) and chemical abundances of different regions within NGC 6905 including its low-ionization clumps; abundances are found to be homogeneous. We used the PoWR stellar atmosphere code to model the spectrum of HD 193949, which is afterwards used in a photoionization model performed with CLOUDY that reproduces the nebular and dust properties for a total mass in the 0.31–0.47 M⊙ range and a mass of C-rich dust of ∼2 × 10−3 M⊙. Adopting a current stellar mass of 0.6 M⊙, our model suggests an initial mass ∼1 M⊙ for HD 193949, consistent with the observations. © 2021 The Author(s). ; VMAGG acknowledges support from the Programa de Becas posdoctorales of the Dirección General de Asuntos del Personal Académico of the Universidad Nacional Autónoma de México (DGAPA, UNAM, Mexico). VMAGG and JAT acknowledge funding by DGAPA UNAM PAPIIT project IA100720. JAT also acknowledges support from the Marcos Moshinsky Fundation (Mexico). GR acknowledge support from Consejo Nacional de Ciencia y Tecnología (CONACYT) for student scholarship. MAG acknowledges support of the Spanish Ministerio de Ciencia, Innovación y Universidades grant PGC2018-102184-B-I00, cofunded by FEDER funds. LS acknowledges funding by DGAPA UNAM PAPIIT project IN-101819. GR-L acknowledges support from CONACYT grant 263373 and PRODEP (Mexico). This work is based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos in La Palma, Spain, of the Instituto de Astrofisica de Canarias. This work uses public data from the IR telescope Spitzer Space Telescope through the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory at the California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). WISE is a joint project of the University of California (Los Angeles, USA) and the JPL/Caltech. The Infrared Astronomical Satellite (IRAS) was a joint project of the US, UK, and the Netherlands. This research is based on observations with AKARI, a JAXA project with the participation of ESA. This work has make extensive use of the NASA's Astrophysics Data System. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

We present an infrared (IR) characterization of the born-again planetary nebulae (PNe) A 30 and A 78 using IR images and spectra. We demonstrate that the carbon-rich dust in A 30 and A 78 is spatially coincident with the H-poor ejecta and coexists with hot X-ray-emitting gas up to distances of 50 arcsec from the central stars of PNe (CSPNe). Dust forms immediately after the born-again event and survives for 1000 yr in the harsh environment around the CSPN as it is destroyed and pushed away by radiation pressure and dragged by hydrodynamical effects. Spitzer IRS spectral maps showed that the broad spectral features at 6.4 and 8.0 μm, attributed to amorphous carbon formed in H-deficient environments, are associated with the disrupted disc around their CSPN, providing an optimal environment for charge exchange reactions with the stellar wind that produces the soft X-ray emission of these sources. Nebular and dust properties are modelled for A 30 with cloudy taking into account different carbonaceous dust species. Our models predict dust temperatures in the 40-230 K range, five times lower than predicted by previous works. Gas and dust masses for the born-again ejecta in A 30 are estimated to be Mgas=4.41+0.550.14× 10-3 M· and M dust=3.20+3.21-2.06× 10-3 M·, which can be used to estimate a total ejected mass and mass-loss rate for the born-again event of 7.61+3.76-2.20× 10-3 M· and M=(5-60)× 10-5 M· yr-1, respectively. Taking into account the carbon trapped into dust grains, we estimate that the C/O mass ratio of the H-poor ejecta of A 30 is larger than 1, which favours the very late thermal pulse model over the alternate hypothesis of a nova-like event. © 2021 The Author(s). ; The authors acknowledge funding by Direccion General de Asuntos del Personal Academico of the Universidad Nacional Autonoma de Mexico (DGAPA, UNAM) project IA100720. JAT thanks Fundacion Marcos Moshinsky (Mexico). VMAGG acknowledges support from the Programa de Becas posdoctorales funded by DGAPA, UNAM. JBRG, SED, and PJH thank Consejo Nacional deCiencias yTecnolog ' ia(CONACYT) Mexico for research student grants. MAGacknowledges support of the SpanishMinisterio de Ciencia, Innovacion y Universidades (MCIU) grant PGC2018-102184-B-I00. GRL acknowledges support from CONACYT (grant 263373) and PRODEP (Mexico). DAGH acknowledges support from the State Research Agency (AEI) of the Spanish Ministry of Science, Innovation and Universities (MCIU) and the European Regional Development Fund (FEDER) under grant AYA2017-88254-P. This study is based on observations made with the instruments NOTCam at the Nordic Optical Telescope (NOT) and CanariCam at the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. NOT is owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku, and the University of Oslo, representing Denmark, Finland, and Norway, the University of Iceland, and Stockholm University. This work makes use of Spitzer IR observations, which was operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work is partially based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This work has made extensive use of NASA's Astrophysics Data System. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

Among the different types of massive stars in advanced evolutionary stages is the enigmatic WN8h type. There are only a few Wolf-Rayet (WR) stars with this spectral type in our Galaxy. It has long been suggested that WN8h-type stars are the products of binary evolution that may harbor neutron stars (NS). One of the most intriguing WN8h stars is the runaway WR 124 surrounded by its magnificent nebula M1-67. We test the presence of an accreting NS companion in WR 124 using ∼100 ks long observations by the Chandra X-ray observatory. The hard X-ray emission from WR 124 with a luminosity of L ∼ 10 erg s is marginally detected. We use the non-local thermodynamic equilibrium stellar atmosphere code PoWR to estimate the WR wind opacity to the X-rays. The wind of a WN8-type star is effectively opaque for X-rays, hence the low X-ray luminosity of WR 124 does not rule out the presence of an embedded compact object. We suggest that, in general, high-opacity WR winds could prevent X-ray detections of embedded NS, and be an explanation for the apparent lack of WR+NS systems.© 2018. The American Astronomical Society. All rights reserved. ; The authors are indebted to the anonymous referee for a detailed revision of the manuscript and constructive suggestions. Support for this Letter was provided by the National Aeronautics and Space Administration through Chandra award No. G07-18014X issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the NASA contract NAS8-03060. J.A.T., M.A.G., and H.T. are funded by UNAM DGAPA PAPIIT project IA100318. L.M.O. acknowledges support by the DLR grant 50 OR 1508 and partial support by the Russian Government Program of Competitive Growth of Kazan Federal University. A.A.C.S. is supported by the Deutsche Forschungsgemeinschaft (DFG) under grant HA 1455/26 and would like to thank STFC for funding under grant No. ST/R000565/1. Y.-H.C. acknowledges support from the Ministry of Science and Technology of Taiwan. T.S. acknowledges support from the German Verbundforschung (DLR) grant 50 OR 1612. J.M.T. acknowledges support from ESP2017-85691-P.