We present a model of a viscously evolving accretion disc around a magnetized neutron star. The model features the varying outer radius of the hot ionized part of the disc due to cooling and the varying inner radius of the disc due to interaction with the magnetosphere. It also includes hindering of accretion on the neutron star because of the centrifugal barrier and irradiation of the outer disc and companion star by X-rays from the neutron star and disc. When setting inner boundary conditions, we take into account that processes at the inner disc occur on a time scale much less than the viscous time scale of the whole disc. We consider three types of outflow from the disc inner edge: zero outflow, one based on MHD calculations, and a very efficient propeller mechanism. The light curves of an X-ray transient after the outburst peak can be calculated by a corresponding, publicly available code. We compare observed light curves of the 2013 burst of Aql X-1 in X-ray and optical bands with modeled ones. We find that the fast drop of the $0.3-10$ keV flux can be solely explained by a radial shrinking of the hot disc. At the same time, models with the neutron star magnetic field $>10^8$ G have better fits because the accretion efficiency behaviour emphasizes the 'knee' on the light curve. We also find that a plato emission can be produced by a disc-reservoir with stalled accretion.
With our neutron star crust cooling code {\tt NSCool} we track the thermal evolution of the neutron star in Aql X-1 over the full accretion outburst history from 1996 until 2015. For the first time, we model many outbursts (23 outbursts were detected) collectively and in great detail. This allows us to investigate the influence of previous outbursts on the internal temperature evolution and to test different neutron star crust cooling scenarios. Aql X-1 is an ideal test source for this purpose, because it shows frequent, short outbursts and thermally dominated quiescence spectra. The source go…
Aql X-1 is the most prolific low mass X-ray binary transient hosting a neutron star. In this paper we focus on the return to quiescence following the 2010 outburst of the source. This decay was monitored thanks to 11 pointed observations taken with XMM-Newton, Chandra and Swift. The decay from outburst to quiescence is very fast, with an exponential decay characteristic time scale of ~2 d. Once in quiescence the X-ray flux of Aql X-1 remained constant, with no further signs of variability or decay. The comparison with the only other well-monitored outburst from Aql X-1 (1997) is tail-telling. …
Aql X-1 is the prototypical low mass X-ray binary transient. The Rossi X-ray Timing Explorer All Sky Monitor provided a ~16 yr coverage revealing 20 outbursts. This is by far the most extensive legacy of outbursts from the same source. We investigated the outbursts characteristics in terms of energetics, peak luminosities, durations, decays and recurrence times. We found that bright outbursts (peak luminosity >10^{37} erg s^-1) equal in number dimmer outbursts (<10^{36.6} erg s^-1). The peak luminosity does not correlate with outburst energetics, durations or quiescent times. We analysed the l…
We present a broad classification of all outbursts detected with the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer (RXTE) and the Monitor of All Sky X-Ray Image (MAXI) of Aql X-1. We identify three types of outbursts; long-high, medium-low, and short-low, based on the duration and maximum flux. We analyse the trends in the "phase-space" of flux-derivative versus flux to demonstrate the differences in the three identified outburst types. We present a spectral analysis of the observations of Aql X-1 performed by the Proportional Counter Array (PCA) onboard RXTE during the 2000 and 201…
The structure and composition of the crust of neutron stars plays an important role in their thermal and magnetic evolution, hence in setting their observational properties. One way to study the crust properties is to measure how it cools after it has been heated during an accretion outburst in a low-mass X-ray binary (LMXB). Such studies have shown that there is a tantalizing source of heat, of currently unknown origin, that is located in the outer layers of the crust and has a strength that varies between different sources and different outbursts. With the aim of understanding the mechanism …
Aql X-1 is a prolific transient neutron star low-mass X-ray binary that exhibits an accretion outburst approximately once every year. Whether the thermal X-rays detected in intervening quiescent episodes are the result of cooling of the neutron star or due to continued low-level accretion remains unclear. In this work we use Swift data obtained after the long and bright 2011 and 2013 outbursts, as well as the short and faint 2015 outburst, to investigate the hypothesis that cooling of the accretion-heated neutron star crust dominates the quiescent thermal emission in Aql X-1. We demonstrate th…
Aql X--1 is one of the most prolific low mass X-ray binary transients (LMXBTs) showing outbursts almost annually. We present the results of our spectral analyses of RXTE/PCA observations of the 2000 and the 2011 outbursts. We investigate the spectral changes related to the changing disk-magnetosphere interaction modes of Aql X--1. The X-ray light curves of the outbursts of LMXBTs typically show phases of fast rise and exponential decay. The decay phase shows a "knee" where the flux goes from the slow decay to the rapid decay stage. We assume that the rapid decay corresponds to a weak propeller…
Similar to black-hole X-ray binary (BHXRB) transients, hysteresis-like state transitions are also seen in some neutron-star X-ray binaries (NSXRBs). Using a method based on wavelets and lightcurves constructed from archival RXTE observations, we extract a minimal timescale over the complete range of transitions for 4U 1608-52 during the 2002 and 2007 outbursts and the 1999 and 2000 outbursts for Aql X-1. We present evidence for a strong positive correlation between this minimal timescale and a similar timescale extracted from the corresponding power spectra of these sources.
Aql X-1 is one of the best-studied neutron star low-mass X-ray binaries. It was previously targeted using quasi-simultaneous radio and X-ray observations during at least 7 different accretion outbursts. Such observations allow us to probe the interplay between accretion inflow (X-ray) and jet outflow (radio). Thus far, these combined observations have only covered one order of magnitude in radio and X-ray luminosity range; this means that any potential radio - X-ray luminosity correlation, $L_R \propto L_X^β$, is not well constrained ($β\approx$ 0.4-0.9, based on various studies) or understood…
We report on quasi-simultaneous observations from radio to X-ray frequencies of the neutron star X-ray binary Aql X-1 over accretion state transitions during its 2016 outburst. All the observations show radio to millimetre spectra consistent with emission from a jet, with a spectral break from optically thick to optically thin synchrotron emission that decreases from ~100 GHz to <5.5 GHz during the transition from a hard to a soft accretion state. The 5.5 GHz radio flux density as the source reaches the soft state, 0.82$\pm$0.03 mJy, is the highest recorded to date for this source. During the …
Accreting neutron stars and black holes in low-mass X-ray binaries (LMXBs) radiate across the electromagnetic spectrum. Linking the emission produced at different wavelengths can provide valuable information about the accretion process and any associated outflows. In this work, we study simultaneous X-ray and UV/optical observations of the neutron star LMXB \source, obtained with the Neil Gehrels Swift Observatory during its 2013, 2014 and 2016 accretion outbursts. We find that the UV/optical and X-ray emission are strongly correlated during all three outbursts. For the 2013 and 2014 episodes,…
The observed evolution of the broad-band spectral energy distribution (SED) in NS X-ray Nova Aql X-1 during the rise phase of a bright FRED-type outburst in 2013 can be understood in the framework of thermal emission from unstationary accretion disc with temperature radial distribution transforming from a single-temperature blackbody emitting ring into the multi-colour irradiated accretion disc. SED evolution during the hard to soft X-ray state transition looks curious, as it can not be repro- duced by the standard disc irradiation model with a single irradiation parameter for NUV, Optical and…
Aql X-1 from dawn 'til dusk: the early rise, fast state transition and decay of its 2024 outburst
Institute of Space Sciences (ICE, CSIC)（空间科学研究所）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚太空研究学院）；INAF/IASF Palermo（意大利国家天体物理研究所巴勒莫分所）；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布里耶拉天文台）；Center for Astrophysics and Space Science (CASS), New York University Abu Dhabi（纽约大学阿布扎比分校天体物理学与空间科学中心）；Departamento de Astrofísica, Universidad de La Laguna（拉帕拉斯大学天体物理学系）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Departament de Fisíca, EEBE, Universitat Politècnica de Catalunya（加泰罗尼亚理工大学EEBE学院物理系）；Center for Nuclear Astrophysics across Messengers (CeNAM)（跨信使核天体物理学中心）
Accretion via disks can make neutron stars in low-mass X-ray binaries (LMXBs) fast spinning, and some of these stars are detected as millisecond pulsars. Here we report a practical way to find out if a neutron star in a transient LMXB has reached the spin equilibrium by disk--magnetosphere interaction alone, and if not, to estimate this spin equilibrium frequency. These can be done using specific measurable source luminosities, such as the luminosity corresponding to the transition between the accretion and propeller phases, and the known stellar spin rate. Such a finding can be useful to test…
We present X-ray observations of novae V2491 Cyg and KT Eri about 9 years post-outburst, of the dwarf nova and post-nova candidate EY Cyg, and of a VY Scl variable. The first three objects were observed with XMM-Newton, KT Eri also with the Chandra ACIS-S camera, V794 Aql with the Chandra ACIS-S camera and High Energy Transmission Gratings. The two recent novae, similar in outburst amplitude and light curve, appear very different at quiescence. Assuming half of the gravitational energy is irradiated in X-rays, V2491 Cyg is accreting at $\dot{m}=1.4\times10^{-9}-10^{-8}M_\odot/yr$, while for KT…
We present the luminosity dwell-time distributions during the hard states of low-mass X-ray binaries containing a neutron star, 4U 1608-52 and AqlX-1, observed with MAXI/GSC. The luminosity distributions show a steep cut-off in the low-luminosity side at $\sim1.0 \times 10^{36}$ erg s$^{-1}$ in both the two sources. The cut-off implies a rapid luminosity decrease in their outburst decay phases, and the feature can be interpreted as due the propeller effect. We estimated the surface magnetic field of the neutron star to be (0.5--1.6) $\times 10^8$ G in 4U 1608-52 and (0.6--1.9) $\times 10^8$ G …
The 2009 November outburst of the neutron star X-ray binary Aquila X-1 was observed with unprecedented radio coverage and simultaneous pointed X-ray observations, tracing the radio emission around the full X-ray hysteresis loop of the outburst for the first time. We use these data to discuss the disc-jet coupling, finding the radio emission to be consistent with being triggered at state transitions, both from the hard to the soft spectral state and vice versa. Our data appear to confirm previous suggestions of radio quenching in the soft state above a threshold X-ray luminosity of about 10% of…
We propose a simplified picture of low mass X-ray binaries containing a neutron star (NS-LMXBs) based on data obtained from AqlX-1 and 4U1608-52 which often produce outbursts. In this picture we propose at least three states and three state transitions; i.e., the states: (1) soft state, (2) hard-high state, and (3) hard-low state, and the state transitions: (i) hard-high state to soft state, (ii) soft state to hard-high state, and (iii) hard-high state to hard-low state or vice versa. Gases from the accretion disc of an NS-LMXB penetrate almost the entire magnetic field and accrete onto the ne…
Strongly magnetized accreting stars are often hypothesized to be in `spin equilibrium' with their surrounding accretion flows, which requires that the accretion rate changes more slowly than it takes the star to reach spin equilibrium. This is not true for most magnetically accreting stars, which have strongly variable accretion outbursts on time-scales much shorter than the time it would take to reach spin equilibrium. This paper examines how accretion outbursts affect the time a star takes to reach spin equilibrium and its final equilibrium spin period. I consider several different models fo…
Nuclear equation-of-state effects on the two-dimensional post-outburst thermal evolution of magnetized neutron-star crusts
State Key Laboratory of Radio Astronomy and Technology, Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台射电天文与技术重点实验室）；University of Chinese Academy of Sciences（中国科学院大学）
We study the temporal and spectral characteristics of SMC X-3 during its 2016 outburst. To probe accretion onto highly magnetized neutron stars (NSs), at the Eddington limit. We obtained XMM-Newton observations of SMC X-3 and combined them with long-term observations by Swift. We studied the temporal and spectral behavior of the source, and its short- and long-term evolution. We constructed a simple toy-model to gain insight into the complex emission pattern of SMC X-3. We confirm the pulse period of the system, derived by previous works and note that the pulse has a complex, three peaked shap…
We have studied the evolution of the Low Frequency Quasi-Periodic Oscillations (LFQPOs) during the rising phase of seven outbursts of the neutron star Soft X-ray Transient (SXT) Aql X$-$1 observed with the \textit{Rossi X-ray Timing Explorer (RXTE)}. The frequency correlation between the low frequency break and the LFQPO sampled on the time scale of $\sim$2 days was seen. Except for the peculiar 2001 outburst, the frequency of the LFQPOs increased with time before the hard-to-soft state transition up to a maximum $ν_{max}$ at $\sim$31 Hz, a factor of $\sim$5 higher than those seen in black hol…
Transient neutron star (NS) LMXBs undergo episodes of accretion, alternated with quiescent periods. During an accretion outburst, the NS heats up due to exothermic accretion-induced processes taking place in the crust. Besides the long-known deep crustal heating of nuclear origin, a likely non-nuclear source of heat, dubbed 'shallow heating', is present at lower densities. Most of the accretion-induced heat slowly diffuses into the core on a timescale of years. Over many outburst cycles, a state of equilibrium is reached when the core temperature is high enough that the heating and cooling (ph…
We study the 2018 outburst of Aql X-1 via the monitor of all sky X-ray image (MAXI) data. We show that the outburst starting in February 2018 is a member of short-low class in the frame of outburst duration and the peak count rate although the outburst morphology is slightly different from the other fast-rise-exponential-decay (FRED) type outbursts with a milder rising stage. We study the partial accretion in the weak propeller stage of Aql X-1 via the MAXI data of the 2018 outburst. We report on the spectral analysis of 3 observations of Aquila X-1 obtained by Insight - hard X-ray modulation …
Strongly-magnetized ($B\geq10^{12}$ G) accreting neutron stars (NSs) are prime targets for studying the launching of jets by objects with a solid surface; while classical jet-launching models predict that such NSs cannot launch jets, recent observations and models argue otherwise. Transient Be/X-ray binaries (BeXRBs) are critical laboratories for probing this poorly-explored parameter space for jet formation. Here, we present the coordinated monitoring campaigns of three BeXRBs across four outbursts: giant outbursts of SAX 2103.5+4545, 1A 0535+262, and GRO J1008-57, as well as a Type-I outburs…
The disc instability model (DIM) has been very successful in explaining the dwarf nova outbursts observed in cataclysmic variables. When, as in intermediate polars (IP), the accreting white dwarf is magnetized, the disc is truncated at the magnetospheric radius, but for mass-transfer rates corresponding to the thermal-viscous instability such systems should still exhibit dwarf-nova outbursts. Yet, the majority of intermediate polars in which the magnetic field is not large enough to completely disrupt the accretion disc, seem to be stable, and the rare observed outbursts, in particular in syst…
We present a model for a super-Eddington accretion disc around a magnetized neutron star taking into account advection of heat and the mass loss by the wind. The model is semi-analytical and predicts radial profiles of all basic physical characteristics of the accretion disc. The magnetospheric radius is found as an eigenvalue of the problem. When the inner disc is in radiation-pressure-dominated regime but does not reach its local Eddington limit, advection is mild, and the radius of the magnetosphere depends weakly on the accretion rate. Once approaching the local Eddington limit, the disc b…
We have characterized the typical temporal behaviour of the bright X-ray flares detected from the three Supergiant Fast X-ray Transients showing the most extreme transient behaviour (XTEJ1739-302, IGRJ17544-2619, SAXJ1818.6-1703). We focus here on the cumulative distributions of the waiting-time (time interval between two consecutive X-ray flares), and the duration of the hard X-ray activity (duration of the brightest phase of an SFXT outburst), as observed by INTEGRAL/IBIS in the energy band 17-50 keV. Adopting the cumulative distribution of waiting-times, it is possible to identify the typic…
The aim of this paper is to investigate the transition of a strongly magnetized neutron star into the accretion regime with very low accretion rate. For this purpose we monitored the Be-transient X-ray pulsar GRO J1008-57 throughout a full orbital cycle. The current observational campaign was performed with the Swift/XRT telescope in the soft X-ray band (0.5-10 keV) between two subsequent Type I outbursts in January and September 2016. The expected transition to the propeller regime was not observed. However, the transitions between different regimes of accretion were detected. In particular, …
Recent studies of black hole and neutron star low mass X-ray binaries (LMXBs) show a positive correlation between the X-ray flux at which the low/hard(LH)-to-high/soft(HS) state transition occurs and the peak flux of the following HS state. By analyzing the data from the All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE), we show that the HS state flux after the source reaches its HS flux peak still correlates with the transition flux during soft X-ray transient (SXT) outbursts. By studying large outbursts or flares of GX 339-4, Aql X-1 and 4U 1705-44, we have found that the …
U 2206+54 is a wind-fed high mass X-ray binary with a main-sequence donor star. The nature of its compact object was recently identified as a slow-pulsation magnetized neutron star. INTEGRAL/IBIS observations have a long-term hard X-ray monitoring of 4U 2206+54 and detected a hard X-ray outburst around 15 December 2005 combined with the RXTE/ASM data.The hard X-ray outburst had a double-flare feature with a duration of $\sim$ 2 days. The first flare showed a fast rise and long time decaying light curve about 15 hours with a peak luminosity of $\sim 4\times 10^{36}$ erg s$^{-1}$ from 1.5 -- 12 …
GK Per, a classical nova of 1901, is thought to undergo variable mass accretion on to a magnetized white dwarf (WD) in an intermediate polar system (IP). We organized a multi-mission observational campaign in the X-ray and ultraviolet (UV) energy ranges during its dwarf nova (DN) outburst in 2015 March-April. Comparing data from quiescence and near outburst, we have found that the maximum plasma temperature decreased from about 26 to 16.2+/-0.4 keV. This is consistent with the previously proposed scenario of increase in mass accretion rate while the inner radius of the magnetically disrupted a…
We present six Chandra X-ray spectra and light curves obtained for the nova V1494 Aql (1999 #2) in outburst. The first three observations were taken with ACIS-I on days 134, 187, and 248 after outburst. The count rates were 1.00, 0.69 and 0.53 cps, respectively. We found no significant periodicity in the ACIS light curves. The X-ray spectra show continuum emission and lines originating from N and O. We found acceptable spectral fits using isothermal APEC models with significantly increased elemental abundances of O and N for all observations. On day 248 after outburst a bright soft component a…
Four significant events of rapid $^{14}$C increase have taken place within the past several thousand years. The physical origin of these rapid increases is still a mystery but must be associated with extremely energetic cosmic processes. Pulsars are highly magnetized neutron stars that emit a beam of electromagnetic radiations. Any sudden release of the energy stored in the magnetic multipole field will trigger outbursts similar to the giant flares of magnetars. Here we show that the relativistic outflow from the outbursts of a nearby pulsar interacting with the interstellar medium generates a…
The defining trait of magnetars, the most strongly magnetized neutron stars (NSs), is their transient activity in the X/$γ$-bands. In particular, many of them undergo phases of enhanced emission, the so-called outbursts, during which the luminosity rises by a factor $\sim$10$-$1000 in a few hours to then decay over months/years. Outbursts often exhibit a thermal spectrum, associated with the appearance of hotter regions on the surface of the star, which subsequently change in shape and cool down. Here we simulate the unfolding of a sudden, localized heat injection in the external crust of a NS…
The magnetosphere of strongly magnetized neutron stars, such as magnetars, can sustain large electric currents. The charged particles return to the surface with large Lorentz factors, producing a particle bombardment. We investigate the transport of radiation in the atmosphere of strongly magnetized neutron stars, in the presence of particle bombardment heating. We solve the radiative transfer equations for a gray atmosphere in the Eddington approximation, accounting for the polarization induced by a strong magnetic field. The solutions show the formation of a hot external layer and a low (uni…
Dwarf novæ (DNe) and low mass X-ray binaries (LMXBs) are compact binaries showing variability on time scales from years to less than seconds. Here, we focus on explaining part of the rapid fluctuations in DNe, following the framework of recent studies on the monthly eruptions of DNe that use a hybrid disk composed of an outer standard disk and an inner magnetized disk. We show that the ionization instability, that is responsible for the monthly eruptions of DNe, is also able to operate in the inner magnetized disk. Given the low density and the fast accretion time scale of the inner magnetized…
V2491 Cygni (Nova Cygni 2008 No.2) was detected as a transient supersoft X-ray source with the Swift XRT as early as 40 days after the outburst, suggesting a very massive white dwarf (WD) close to the Chandrasekhar limit. We present a unified model of near infrared, optical, and X-ray light curves for V2491 Cyg, and have estimated, from our best-fit model, the WD mass to be 1.3 \pm 0.02 M_\sun with an assumed chemical composition of the envelope, X=0.20, Y= 0.48, X_{CNO} =0.20, X_{Ne} =0.10, and Z = 0.02 by mass weight. We strongly recommend detailed composition analysis of the ejecta because …
Cyclotron line scattering features are detected in a few tens of X-ray pulsars (XRPs) and used as direct indicators of a strong magnetic field at the surface of accreting neutron stars (NSs). In a few cases, cyclotron lines are known to be variable with accretion luminosity of XRPs. It is accepted that the observed variations of cyclotron line scattering features are related to variations of geometry and dynamics of accretion flow above the magnetic poles of a NS. A positive correlation between the line centroid energy and luminosity is typical for sub-critical XRPs, where the accretion result…
Magnetars are young and highly magnetized neutron stars which display a wide array of X-ray activity including short bursts, large outbursts, giant flares and quasi-periodic oscillations, often coupled with interesting timing behavior including enhanced spin-down, glitches and anti-glitches. The bulk of this activity is explained by the evolution and decay of an ultrastrong magnetic field, stressing and breaking the neutron star crust, which in turn drives twists of the external magnetosphere and powerful magnetospheric currents. The population of detected magnetars has grown to about 30 objec…
We have identified four new black hole candidates in M31 globular clusters using 123 Chandra, and 4 XMM-Newton observations of the M31 central region. The X-ray source associated with Bo 163 (XB163) is a recurrent transient, with the highest luminosity ~1.4E+38 erg/s, considerably brighter than any outbursts from the neutron star transients Aql X-1 or 4U 1608-452; the outburst apparently started ~45 days earlier than the observed peak, hence the luminosity could have been considerably higher. We identified XB082, XB153 and XB185 as BHCs by observing "low state" emission spectra at luminosities…
Accreting millisecond pulsars show significant variability of their pulse profiles, especially at low accretion rates. On the other hand, their X-ray spectra are remarkably similar with not much variability over the course of the outbursts. For the first time, we have discovered that during the 2008 outburst of SAX J1808.4-3658 a major pulse profile change was accompanied by a dramatic variation of the disc luminosity at almost constant total luminosity. We argue that this phenomenon is related to a change in the coupling between the neutron star magnetic field and the accretion disc. The vary…
This study investigates elastic deformation driven by the Hall drift in a magnetized neutron-star crust. Although the dynamic equilibrium initially holds without elastic displacement, the magnetic-field evolution changes the Lorentz force over a secular timescale, which inevitably causes the elastic deformation to settle in a new force balance. Accordingly, elastic energy is accumulated, and the crust is eventually fractured beyond a particular threshold. We assume that the magnetic field is axially symmetric, and we explicitly calculate the breakup time, maximum elastic energy stored in the c…
We present a toy model for radio emission in HMXBs with strongly magnetized neutron stars (NS) where a wind-collision region is formed by the NS outflow and the stellar wind of the massive companion. Radio emission is expected from the synchrotron radiation of shock-accelerated electrons and the free-free emission of the stellar wind. We found that the predicted relation between the GHz luminosity ($L_R$) and the accretion X-ray luminosity ($L_X$) can be written as $L_R \propto L_X^b$ for most parameters. No correlation with X-rays is expected ($b=0$) when the thermal emission of the stellar w…
It is now widely accepted that most ultraluminous X-ray sources (ULXs) are binary systems whose large (above $10^{39}$ erg s$^{-1}$) apparent luminosities are explained by super-Eddington accretion onto a stellar-mass compact object. Many of the ULXs, especially those containing magnetized neutron stars, are highly variable; some exhibit transient behaviour. Large luminosities might imply large accretion discs that could be therefore prone to the thermal-viscous instability known to drive outbursts of dwarf novae and low-mass X-ray binary transient sources. The aim of this paper is to extend a…
Transient Be/X-ray binary systems, wherein a compact object accretes from a Be-companion star, can show giant and periastron outbursts. During the decay of their giant outbursts, some Be/X-ray binaries also show X-ray re-brightenings, the origin of which is not understood. Recently, we presented the discovery of a jet from a neutron star Be/X-ray binary, observed during the giant outburst of Swift J0243.6+6124. Here, we present continued radio monitoring of its 2017/2018 giant outburst decay and a re-brightening of this source. During the former, we observe a radio flare with a steep radio spe…
The 6.67 hr periodicity and the variable X-ray flux of the central compact object (CCO) at the center of the SNR RCW 103, named 1E 161348-5055, have been always difficult to interpret within the standard scenarios of an isolated neutron star or a binary system. On 2016 June 22, the Burst Alert Telescope (BAT) onboard Swift detected a magnetar-like short X-ray burst from the direction of 1E 161348-5055, also coincident with a large long-term X-ray outburst. Here we report on Chandra, NuSTAR, and Swift (BAT and XRT) observations of this peculiar source during its 2016 outburst peak. In particula…
