TY  - JOUR
A1  - Fang, X.
A1  - Guerrero, Martín A.
A1  - Marquez-Lugo, R. A.
A1  - Toala, Jesús Alberto
A1  - Arthur, S. J.
A1  - Chu, Y.-H.
A1  - Blair, William P.
A1  - Gruendl, R. A.
A1  - Hamann, Wolf-Rainer
A1  - Oskinova, Lida
A1  - Todt, Helge Tobias
T1  - Expansion of hydrogen-poor knots in the born-again planetary nebulae A30 and A78
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We analyze the expansion of hydrogen-poor knots and filaments in the born-again planetary nebulae A30 and A78 based on Hubble Space Telescope ( HST) images obtained almost 20 yr apart. The proper motion of these features generally increases with distance to the central star, but the fractional expansion decreases, i.e., the expansion is not homologous. As a result, there is not a unique expansion age, which is estimated to be 610-950 yr for A30 and 600-1140 yr for A78. The knots and filaments have experienced complex dynamical processes: the current fast stellar wind is mass loaded by the material ablated from the inner knots; the ablated material is then swept up until it shocks the inner edges of the outer, hydrogen-rich nebula. The angular expansion of the outer filaments shows a clear dependence on position angle, indicating that the interaction of the stellar wind with the innermost knots channels the wind along preferred directions. The apparent angular expansion of the innermost knots seems to be dominated by the rocket effect of evaporating gas and by the propagation of the ionization front inside them. Radiation-hydrodynamical simulations show that a single ejection of material followed by a rapid onset of the stellar wind and ionizing flux can reproduce the variety of clumps and filaments at different distances from the central star found in A30 and A78.
KW  - ISM: kinematics and dynamics
KW  - planetary nebulae: individual (A30 and A78)
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/797/2/100
SN  - 0004-637X
SN  - 1538-4357
VL  - 797
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Toala, Jesús Alberto
A1  - Guerrero, Martín A.
A1  - Todt, Helge Tobias
A1  - Hamann, Wolf-Rainer
A1  - Chu, Y.-H.
A1  - Gruendl, R. A.
A1  - Schönberner, Detlef
A1  - Oskinova, Lida
A1  - Marquez-Lugo, R. A.
A1  - Fang, X.
A1  - Ramos-Larios, Gerardo
T1  - The born-again Planetary nebula A78: an X-RAY twin of A30
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We present the XMM-Newton discovery of X-ray emission from the planetary nebula (PN) A78, the second born-again PN detected in X-rays apart from A30. These two PNe share similar spectral and morphological characteristics: they harbor diffuse soft X-ray emission associated with the interaction between the H-poor ejecta and the current fast stellar wind and a point-like source at the position of the central star (CSPN). We present the spectral analysis of the CSPN, using for the first time an NLTE code for expanding atmospheres that takes line blanketing into account for the UV and optical spectra. The wind abundances are used for the X-ray spectral analysis of the CSPN and the diffuse emission. The X-ray emission from the CSPN in A78 can be modeled by a single C VI emission line, while the X-ray emission from its diffuse component is better described by an optically thin plasma emission model with a temperature of kT = 0.088 keV (T approximate to 1.0 x 10(6) K). We estimate X-ray luminosities in the 0.2-2.0 keV energy band of L-X,L-CSPN =(1.2 +/- 0.3) x 10(31) erg s(-1) and L-X,L-DIFF =(9.2 +/- 2.3) x 10(30) erg s(-1) for the CSPN and diffuse components, respectively.
KW  - planetary nebulae: general
KW  - planetary nebulae: individual (A78)
KW  - stars: winds, outflows
KW  - X-rays: ISM
Y1  - 2015
U6  - https://doi.org/10.1088/0004-637X/799/1/67
SN  - 0004-637X
SN  - 1538-4357
VL  - 799
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Toala, Jesús Alberto
A1  - Oskinova, Lida
A1  - Gonzalez-Galan, Ana
A1  - Guerrero, Martín A.
A1  - Ignace, R.
A1  - Pohl, Martin
T1  - X-RAY OBSERVATIONS OF BOW SHOCKS AROUND RUNAWAY O STARS. THE CASE OF zeta OPH AND BD+43 degrees 3654
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations toward the runaway stars zeta Oph by Chandra and Suzaku and of BD+43 degrees 3654 by XMM-Newton to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident with the bow shocks; nonetheless, diffuse emission was detected in the vicinity of zeta Oph. After a careful analysis of its spectral characteristics, we conclude that this emission has a thermal nature with a plasma temperature of T approximate to 2 x 10(6) K. The cometary shape of this emission seems to be in line with recent predictions of radiation-hydrodynamic models of runaway stars. The case of BD+43 degrees 3654 is puzzling, as non-thermal emission has been reported in a previous work for this source.
KW  - stars: individual (zeta Oph, BD+43 degrees 3654)
KW  - stars: winds, outflows
Y1  - 2016
U6  - https://doi.org/10.3847/0004-637X/821/2/79
SN  - 0004-637X
SN  - 1538-4357
VL  - 821
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - GEN
A1  - Oskinova, Lida
A1  - Guerrero, Martín A.
A1  - Hénault-Brunet, Vincent
A1  - Sun, W.
A1  - Chu, You-Hua
A1  - Evans, Chris
A1  - Gallagher, John S.
A1  - Gruendl, Robert A.
A1  - Reyes-Iturbide, Jorge
T1  - The slow X-ray pulsar SXP 1062 and associated supernova remnant in the Wing of the Small Magellanic Cloud
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - SXP 1062 is an exceptional case of a young neutron star in a wind-fed high-mass X-ray binary associated with a supernova remnant. A unique combination of measured spin period, its derivative, luminosity and young age makes this source a key probe for the physics of accretion and neutron star evolution. Theoretical models proposed to explain the properties of SXP 1062 shall be tested with new data.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 591 
KW  - stars: emission-line
KW  - Be
KW  - X-rays: binaries
KW  - pulsars: individual (SXP 1062)
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415135
SN  - 1866-8372
IS  - 591
ER  - 
TY  - JOUR
A1  - Toalá, Jesús Alberto
A1  - Guerrero, Martín A.
A1  - Chu, Y.-H.
A1  - Arthur, S. J.
A1  - Gruendl, R. A.
T1  - Diffuse X-ray Emission within Wolf-Rayet Nebulae
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - We discuss our most recent findings on the diffuse X-ray emission within Wolf-Rayet (WR) nebulae. The best-quality X-ray observations of these objects are those performed by XMM- Newton and Chandra towards S 308, NGC 2359, and NGC 6888. Even though these three WR nebulae might have different formation scenarios, they all share similar characteristics: i) the main plasma temperatures of the X-ray-emitting gas is found to be T =[1–2]×^K, ii) the diffuse X-ray emission is confined inside the [O iii] shell, and iii) their X-ray luminosities and electron densities in the 0.3–2.0 keV energy range are LX ≈10^33–10^34 erg s-1  and ne ≈0.1–1 cm^-3 . These properties and the nebular-like abundances of the hot gas suggest mixing and/or thermal conduction is taking an important rôle reducing the temperature of the hot bubble.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88316
SP  - 333
EP  - 336
ER  - 
TY  - GEN
A1  - Guerrero, Martín A.
A1  - Chu, You-Hua
A1  - Hamann, Wolf-Rainer
A1  - Oskinova, Lida
A1  - Schönberner, Detlef
A1  - Todt, Helge Tobias
A1  - Steffen, Matthias
A1  - Ruiz, Nieves
A1  - Gruendl, Robert A.
A1  - Blair, William P.
T1  - Ablation and wind mass-loading in the born-again planetary nebula A 30
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - We present XMM-Newton and Chandra observations of the born-again planetary nebula A 30. These X-ray observations reveal a bright unresolved source at the position of the central star whose X-ray luminosity exceeds by far the model expectations for photospheric emission and for shocks within the stellar wind. We suggest that a “born-again hot bubble” may be responsible for this X-ray emission. Diffuse X-ray emission associated with the petal-like features and one of the H-poor knots seen in the optical is also found. The weakened emission of carbon lines in the spectrum of the diffuse emission can be interpreted as the dilution of stellar wind by mass-loading or as the detection of material ejected during a very late thermal pulse.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 563 
KW  - planetary nebulae: individual (A 30)
KW  - X-rays: ISM
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412341
SN  - 1866-8372
IS  - 563
ER  - 
TY  - JOUR
A1  - Guerrero, Martín A.
A1  - Ruiz, N.
A1  - Hamann, Wolf-Rainer
A1  - Chu, Y.-H.
A1  - Todt, Helge Tobias
A1  - Schönberner, Detlef
A1  - Oskinova, Lida
A1  - Gründl, R. A.
A1  - Steffen, M.
A1  - Blair, William P.
A1  - Toala, Jesús Alberto
T1  - Rebirth of X-Ray emission from the born-again planetary Nebula A30
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The planetary nebula A30 is believed to have undergone a very late thermal pulse resulting in the ejection of knots of hydrogen-poor material. Using multi-epoch Hubble Space Telescope images, we have detected the angular expansion of these knots and derived an age of 850(-150)(+280) yr. To investigate the spectral and spatial properties of the soft X-ray emission detected by ROSAT, we have obtained Chandra and XMM-Newton deep observations of A30. The X-ray emission from A30 can be separated into two components: a point source at the central star and diffuse emission associated with the hydrogen-poor knots and the cloverleaf structure inside the nebular shell. To help us assess the role of the current stellar wind in powering this X-ray emission, we have determined the stellar parameters and wind properties of the central star of A30 using a non-LTE model fit to its optical and UV spectra. The spatial distribution and spectral properties of the diffuse X-ray emission are highly suggestive that it is generated by the post-born-again and present fast stellar winds interacting with the hydrogen-poor ejecta of the born-again event. This emission can be attributed to shock-heated plasma, as the hydrogen-poor knots are ablated by the stellar winds, under which circumstances the efficient mass loading of the present fast stellar wind raises its density and damps its velocity to produce the observed diffuse soft X-rays. Charge transfer reactions between the ions of the stellar winds and material of the born-again ejecta have also been considered as a possible mechanism for the production of diffuse X-ray emission, and upper limits on the expected X-ray production by this mechanism have been derived. The origin of the X-ray emission from the central star of A30 is puzzling: shocks in the present fast stellar wind and photospheric emission can be ruled out, while the development of a new, compact hot bubble confining the fast stellar wind seems implausible.
KW  - planetary nebulae: general
KW  - planetary nebulae: individual (A30)
KW  - stars: winds, outflows
KW  - X-rays: ISM
Y1  - 2012
U6  - https://doi.org/10.1088/0004-637X/755/2/129
SN  - 0004-637X
VL  - 755
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Oskinova, Lida
A1  - Sun, W.
A1  - Evans, C. J.
A1  - Henault-Brunet, V.
A1  - Chu, Y.-H.
A1  - Gallagher, J. S.
A1  - Guerrero, Martín A.
A1  - Gruendl, R. A.
A1  - Güdel, M.
A1  - Silich, S.
A1  - Chen, Y.
A1  - Naze, Y.
A1  - Hainich, Rainer
A1  - Reyes-Iturbide, J.
T1  - Discovery of x-ray emission from young suns in the small magellanic  cloud
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low-and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low-and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.
KW  - Magellanic Clouds
KW  - ISM: bubbles
KW  - H II regions
KW  - stars: winds, outflows
KW  - stars: pre-main sequence
KW  - X-rays: stars
Y1  - 2013
U6  - https://doi.org/10.1088/0004-637X/765/1/73
SN  - 0004-637X
VL  - 765
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Guerrero, Martin A.
A1  - Fang, Xuan
A1  - Miller Bertolami, Marcelo Miguel
A1  - Ramos-Larios, Gerardo
A1  - Todt, Helge Tobias
A1  - Alarie, Alexandre
A1  - Sabin, Laurence
A1  - Miranda, Luis F.
A1  - Morisset, Christophe
A1  - Kehrig, Carolina
A1  - Zavala, Saul A.
T1  - The inside-out planetary nebula around a born-again star
JF  - Nature Astronomy
N2  - Planetary nebulae are ionized clouds of gas formed by the hydrogen-rich envelopes of low- and intermediate-mass stars ejected at late evolutionary stages. The strong UV flux from their central stars causes a highly stratified ionization structure, with species of higher ionization potential closer to the star. Here, we report on the exceptional case of HuBi 1, a double-shell planetary nebula whose inner shell presents emission from low-ionization species close to the star and emission from high-ionization species farther away. Spectral analysis demonstrates that the inner shell of HuBi 1 is excited by shocks, whereas its outer shell is recombining. The anomalous excitation of these shells can be traced to its low-temperature [WC10] central star whose optical brightness has declined continuously by 10 magnitudes in a period of 46 years. Evolutionary models reveal that this star is the descendant of a low-mass star (≃1.1 M⊙) that has experienced a ‘born-again’ event1 whose ejecta shock-excite the inner shell. HuBi 1 represents the missing link in the formation of metal-rich central stars of planetary nebulae from low-mass progenitors, offering unique insight regarding the future evolution of the born-again Sakurai’s object2. Coming from a solar-mass progenitor, HuBi 1 represents a potential end-state for our Sun.
KW  - Astronomy and astrophysics
KW  - Astronomy and planetary science
KW  - Interstellar medium
KW  - Stars
KW  - Stellar evolution
Y1  - 2018
U6  - https://doi.org/10.1038/s41550-018-0551-8
SN  - 2397-3366
VL  - 2
IS  - 10
SP  - 784
EP  - 789
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Henault-Brunet, V.
A1  - Oskinova, Lida
A1  - Guerrero, Martín A.
A1  - Sun, W.
A1  - Chu, Y.-H.
A1  - Evans, C. J.
A1  - Gallagher, J. S.
A1  - Gruendl, R. A.
A1  - Reyes-Iturbide, J.
T1  - Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the wing of the small magellanic cloud
JF  - Monthly notices of the Royal Astronomical Society
N2  - We report on a new Be/X-ray pulsar binary located in the Wing of the Small Magellanic Cloud (SMC). The strong pulsed X-ray source was discovered with the Chandra and XMM-Newton X-ray observatories. The X-ray pulse period of 1062 s is consistently determined from both Chandra and XMM-Newton observations, revealing one of the slowest rotating X-ray pulsars known in the SMC. The optical counterpart of the X-ray source is the emission-line star 2dFS 3831. Its B0-0.5(III)e+ spectral type is determined from VLT-FLAMES and 2dF optical spectroscopy, establishing the system as a Be/X-ray binary (Be-XRB). The hard X-ray spectrum is well fitted by a power law with additional thermal and blackbody components, the latter reminiscent of persistent Be-XRBs. This system is the first evidence of a recent supernova in the low-density surroundings of NGC602. We detect a shell nebula around 2dFS 3831 in H alpha and [OIII] images and conclude that it is most likely a supernova remnant. If it is linked to the supernova explosion that created this new X-ray pulsar, its kinematic age of (2-4) x 10(4) yr provides a constraint on the age of the pulsar.
KW  - stars: emission-line, Be
KW  - ISM: supernova remnants
KW  - Magellanic Clouds
KW  - X-rays: binaries
Y1  - 2012
U6  - https://doi.org/10.1111/j.1745-3933.2011.01183.x
SN  - 0035-8711
VL  - 420
IS  - 1
SP  - L13
EP  - L17
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Guerrero, Martín A.
T1  - Planetary nebulae and Their Central Stars in X-rays
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - Two types of X-ray sources are mostly found in planetary nebulae (PNe): point sources at their central stars and diffuse emission inside hot bubbles. Here we describe these two types of sources based on the most recent observations obtained in the framework of the Chandra Planetary Nebula Survey, ChanPlaNS, an X-ray survey targeting a volume-limited sample of PNe. Diffuse X-ray emission is found preferentially in young PNe with sharp, closed inner
shells. Point sources of X-ray emission at the central stars reveal magnetically active binary companions and shock-in stellar winds.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88160
SP  - 263
EP  - 266
ER  - 
TY  - JOUR
A1  - Toala, Jesús Alberto
A1  - Oskinova, Lida
A1  - Hamann, Wolf-Rainer
A1  - Ignace, Richard
A1  - Sander, Andreas Alexander Christoph
A1  - Shenar, Tomer
A1  - Todt, Helge Tobias
A1  - Chu, Y. -H.
A1  - Guerrero, Martin A.
A1  - Hainich, Rainer
A1  - Torrejon, Jose Miguel
T1  - On the Apparent Absence of Wolf-Rayet plus Neutron Star Systems
BT  - the Curious Case of WR124
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - 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 similar to 100 ks long observations by the Chandra X-ray observatory. The hard X-ray emission from WR 124 with a luminosity of L-X similar to 10(31) erg s(-1) 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.
KW  - circumstellar matter
KW  - ISM: jets and outflows
KW  - stars: massive
KW  - stars: evolution
KW  - stars: neutron
KW  - stars: Wolf-Rayet
Y1  - 2018
U6  - https://doi.org/10.3847/2041-8213/aaf39d
SN  - 2041-8205
SN  - 2041-8213
VL  - 869
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Toalá, Jesús Alberto
A1  - Ramos-Larios, Gerardo
A1  - Guerrero, Martin A.
A1  - Todt, Helge Tobias
T1  - Hidden IR structures in NGC40
BT  - Signpost of an ancient born-again event
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present the analysis of infrared (IR) observations of the planetary nebula NGC40 together with spectral analysis of its [WC]-type central starHD826. Spitzer IRS observations were used to produce spectral maps centred at polycyclic aromatic hydrocarbons (PAH) bands and ionic transitions to compare their spatial distribution. The ionic lines show a clumpy distribution of material around the main cavity of NGC40, with the emission from [Ar II] being the most extended, whilst the PAHs show a rather smooth spatial distribution. Analysis of ratio maps shows the presence of a toroidal structure mainly seen in PAH emission, but also detected in a Herschel PACS 70 mu m image. We argue that the toroidal structure absorbs the UV flux from HD826, preventing the nebula to exhibit lines of high-excitation levels as suggested by previous authors. We discuss the origin of this structure and the results from the spectral analysis of HD826 under the scenario of a late thermal pulse.
KW  - stars: carbon
KW  - stars: evolution
KW  - stars: winds, outflows
KW  - ISM: molecules
KW  - planetary nebulae: individual: NGC40
KW  - infrared: ISM
Y1  - 2019
U6  - https://doi.org/10.1093/mnras/stz624
SN  - 0035-8711
SN  - 1365-2966
VL  - 485
IS  - 3
SP  - 3360
EP  - 3369
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - González-Galán, Ana
A1  - Oskinova, Lida
A1  - Popov, Sergei B.
A1  - Haberl, F.
A1  - Kühnel, M.
A1  - Gallagher, John S.
A1  - Schurch, Matthew
A1  - Guerrero, Martín A.
T1  - A multiwavelength study of SXP 1062, the long-period X-ray pulsar associated with a supernova remnant
JF  - Monthly notices of the Royal Astronomical Society
N2  - SXP 1062 is a Be X-ray binary (BeXB) located in the Small Magellanic Cloud. It hosts a long-period X-ray pulsar and is likely associated with the supernova remnant MCSNR J0127−7332. 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.
KW  - stars: neutron
KW  - pulsars: individual: SXP 1062
KW  - galaxies: individual: Small Magellanic Cloud
KW  - X-rays: binaries
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx3127
SN  - 0035-8711
SN  - 1365-2966
VL  - 475
IS  - 2
SP  - 2809
EP  - 2821
PB  - Oxford University Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Ramos-Larios, Gerardo
A1  - Toala, Jesús Alberto
A1  - Rodriguez-Gonzalez, Janis B.
A1  - Guerrero, Martin A.
A1  - Gomez-Gonzalez, Víctor Mauricio Alfonso
T1  - Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC4406. MUSE spectra are extracted from the rings to unambiguously assess for the first time in a PN their physical conditions, electron density (n(e)), and temperature (T-e). The rings are found to have similar T-e as the rim of the main nebula, but smaller n(e). Ratios between different ionic species suggest that the rings of IC4406 have a lower ionization state than the main cavity, in contrast to what was suggested for the rings in NGC 6543, the Cat's Eye Nebula.
KW  - stars: evolution
KW  - stars: winds, outflows
KW  - planetary nebulae: general;
KW  - planetary nebulae: individual: IC4406
Y1  - 2022
U6  - https://doi.org/10.1093/mnras/stac605
SN  - 0035-8711
SN  - 1365-2966
VL  - 513
IS  - 2
SP  - 2862
EP  - 2868
PB  - Oxford Univ. Press
CY  - Oxford
ER  -