We present the first {\it XMM-Newton} observation of the classical supergiant high-mass X-ray binary XTE J1855$-$026 taken entirely during the eclipse of the neutron star (NS), covering the orbital phases $ϕ= 0.00-0.11$. The analysis of the data allows us to a) compare with the parameters obtained during the existing pre eclipse observation and b) explore the back illuminated stellar wind of the B0I type donor. The black body component, used to describe the soft excess during pre eclipse, is not observed during eclipse. It must be then produced near the NS or along the donor-NS line. The $0.3-10$ keV luminosity during eclipse ($\sim 10^{34}$ erg s$^{-1}$) is 70 times lower than pre eclipse. The intensity of the Fe K$α$ line, in the average eclipse spectrum, is $\sim 7.4$ times lower than the one measured during pre eclipse. Since K$α$ photons can not be resonantly scattered in the wind, the vast majority of Fe K$α$ emission must come from distances within $1R_{*}$ from the NS. The eclipse spectrum is successfully modelled through the addition of two photoionized plasmas, one with low ionization ($\logξ_{\rm 1,cold}=0.36$) and high emission measure ($EM_{\rm 1,cold}\approx 3\times 10^{59}$ cm$^{-3}$) and another with high ionization ($\logξ_{\rm 2,hot}=3.7$) and low emission measure ($EM_{\rm hot}\approx 2\times 10^{56}$ cm$^{-3}$). Assuming that the cold and hot gas phases are the clumps and the interclump medium of the stellar wind, respectively, and a clump volume filling factor of $\approx [0.04-0.05]$, typical for massive stars, a density contrast between clumps and the interclump medium of $n_{\rm c}/n_{\rm i}\approx 180$ is deduced, in agreement with theoretical expectations and optical-UV observations of massive star winds.
The study of X-ray reprocessing is one of the key diagnostic tools to probe the environment in X-ray binary systems. One difficult aspect of studying X-ray reprocessing is the presence of much brighter primary radiation from the compact star together with the reprocessed radiation. In contrast for eclipsing systems, the X-rays we receive during eclipse are only those produced by reprocessing of the emission from the compact star by the surrounding medium. We report results from a spectral study of the X-ray emission during eclipse and outside eclipse (when available) in 9 high mass X-ray binar…
We present an X-ray eclipse timing analysis of the transient low mass X-ray binary XTE J1710-281. We report observations of 57 complete X-ray eclipses, made with the proportional counter array detectors aboard the RXTE satellite. Using the eclipse timing technique, we have derived a constant orbital period of 0.1367109674 (3) d, during the period from MJD 52132 upto MJD 54410; and 1σ limits of -1.6 $\times$ 10^ -12 d d-1 and 0.2 $\times$ 10^ -12 d d-1 , on the period derivative. This puts constraints on the minimum timescale of secular orbital period evolution of 2.34 $\times$ 10^8 yr for a pe…
We present the pulsation and spectral characteristics of the HMXB 4U 0114+65 during a \emph{Suzaku} observation covering the part of the orbit that included the previously known low intensity emission of the source (dip) and the egress from this state. This dip has been interpreted in previous works as an X-ray eclipse. Notably, in this Suzaku observation, the count rate during and outside the dip vary by a factor of only 2-4 at odds with the eclipses of other HMXBs, where the intensity drops upto two orders of magnitude. The orbital intensity profile of 4U 0114+65 is characterized by a narrow…
We present an analysis of the first observation of the iconic High Mass X-ray Binary \so with the \chandra High Energy Transmission Gratings during an X-ray eclipse. The goal of the observation was to study the structure/physical conditions in the clumpy stellar wind through high resolution spectroscopy. We find that: a) emission line brightness from K shell transitions, corresponding to near neutral species, directly correlates with continuum illumination. However, these lines do not greatly diminish during eclipse. This is readily explained if fluorescence K$α$ emission comes from the bulk o…
We report the first detection of highly ionized Fe species in the X-ray spectrum of the eclipsing and dipping Low Mass X-ray Binary XTE J1710-281. Using archival Chandra and Suzaku observations, we have carried out a spectro-timing analysis of the source during three different epochs. We compare the average orbital profile and obtain differences in pre-eclipse dip morphologies between different observation epochs. We observe an orbit to orbit evolution of the dips for the first time in this source in both the Chandra observations, reflecting changes in the structure of the accretion disc in ti…
In the absence of detectable pulsations in the eclipsing High Mass X-ray binary 4U 1700-37, the orbital period decay is necessarily determined from the eclipse timing measurements. We have used the earlier reported mid-eclipse time measurements of 4U 1700-37 together with the new measurements from long term light curves obtained with the all sky monitors RXTE-ASM, Swift-BAT and MAXI-GSC, as well as observations with RXTE-PCA, to measure the long term orbital evolution of the binary. The orbital period decay rate of the system is estimated to be ${\dot{P}}/P = -(4.7 \pm 1.9) \times 10^{-7}$ yr$…
We present an updated measurement of orbital period evolution of LMXB XTE J1710-281 by using eclipse timing technique. Using data obtained with XMM-Newton, Suzaku, RXTE, Chandra and AstroSat observatories, we report 21 new measurements of X-ray mid-eclipse times. We have discovered a third orbital period glitch in XTE J1710-281 with an F-test false alarm probability of ~0.7% for occurrence of the third glitch and report detection of four distinct epochs of orbital period in this system. This work presents a more robust estimation of occurrence of the second orbital period glitch. However, the …
We present the orbital X-ray modulation study of three high mass X- ray binary systems, IGR J18027-2016, IGR J18483-0311 and IGR J16318-4848 using data obtained with RXTE-ASM, Swift-BAT and INTEGRAL-ISGRI. Using the long term light curves of the eclipsing HMXB IGR J18027-2016, obtained with Swift-BAT in the energy range 15-50 keV and INTEGRAL-ISGRI in the energy range 22-40 keV, we have determined three new mid eclipse times. The newly determined mid eclipse times together with the known values were used to derive an accurate value of the orbital period of 4.5693(4) d at MJD 52168 and an upper…
Physical parameters of both the mass donor and compact object can be constrained in X-ray binaries with well-defined eclipses, as our survey of wind-fed supergiant X-ray binaries (SGXBs) IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016 and XTE J1855-026 reveals. Using the orbital period and Kepler's third law, we express the eclipse half-angle in terms of radius, inclination angle and the sum of the masses. Pulse-timing and radial velocity curves can give masses of both the donor and compact object as in the case of the "double-lined" binaries IGR J18027-2016 and XTE J1855-02…
IGR J16493-4348 is a supergiant high mass X-ray binary discovered by INTEGRAL in 2004. The source is detected at a significance level of $\sim21$ standard deviations in the Swift-BAT survey data collected during the first 54 months of the Swift mission. The timing analysis reveals an orbital period of $\sim$6.78 days and the presence of a full eclipse of the compact ob\ ject. The dynamical range (variability up to a factor $\sim$20) observed during the BAT monitoring suggests that IGR J16493-4348 is a wind-fed system. The derived semi-major axis of the binary system is $\sim55 R_{\sun}$ with a…
Our goal is to understand the specificities of highly absorbed sgHMXB and in particular of the companion stellar wind, thought to be responsible for the strong absorption. We have monitored IGR J17252-3616, a highly absorbed system featuring eclipses, with XMM-Newton to study the vari- ability of the column density and of the Fe Kα emission line along the orbit and during the eclipses. We also built a 3D model of the structure of the stellar wind to reproduce the observed variability. We first derived a refined orbital solution built from INTEGRAL, RXTE and XMM data. The XMM monitoring campaig…
The orbital profile of the High Mass X-ray binary IGR J16393-4643 shows a dip in its X-ray intensity, which was previously interpreted as an eclipse. Unlike most eclipsing HMXBs, where the X-ray eclipses are about two orders of magnitude fainter compared to the out of eclipse emission, this particular eclipse like feature is narrow and partial, casting doubt if it is indeed an eclipse. To further investigate the nature of this low intensity orbital phase, we use a large number of observations with Swift-XRT, covering the entire orbital phase. The soft X-ray observations also show this low inte…
We present a comprehensive analysis of the whole sample of available XMM-Newton observations of High Mass X-ray Binaries (HMXBs) until August, 2013, focusing on the FeKα emission line. This line is a key tool to better understand the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We have collected observations from 46 HMXBs, detecting FeKα in 21 of them. We have used the standard classification of HMXBs to divide the sample in different groups. We find that: (1) FeKα is centred at a mean value of 6.42 keV. Considering the…
SFXTs are a new class of HMXB unveiled by INTEGRAL. They are extreme systems characterised by very short outbursts (a few hours) and extreme X-ray luminosity dynamic ranges (~10^{4}). Ten confirmed systems are currently known and have shown parallels with both Sg-XRBs and Be-XRBs. Temporal studies across all timescales are key to understanding both the place of SFXTs within the HMXB hierarchy and the accretion mechanisms at work within the objects. Here we present the discovery of a new 51.47 \pm 0.02 day orbital period in the SFXT XTE J1739$-$302 using INTEGRAL observations. We also present a…
X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. Potential targets for future X-ray polarization observations are the high-mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early type star. In this pap…
Cen X-3 is a compact high mass X-ray binary likely powered by Roche lobe overflow. We present a phase-resolved X-ray spectral and timing analysis of two pointed XMM-Newton observations. The first one took place during a normal state of the source, when it has a luminosity $L_{\rm X}\sim 10^{36}$ erg s$^{-1}$. This observation covered orbital phases $ϕ= 0.00-0.37$, i.e. the egress from the eclipse. The egress lightcurve is highly structured, showing distinctive intervals. We argue that different intervals correspond to the emergence of different emitting structures. The lightcurve analysis enab…
(abridged) We analyzed the archived XMM-Newton observation of the poorly studied low-mass X-ray binary XTE J1710-281 performed in 2004 that covered one orbital period of the system (3.8 hr). The source shows dips as well as eclipses, hence it is viewed close to edge-on. We modeled the spectral changes between persistent and dips in the framework of the partial covering model and the ionized absorber approach. The persistent spectrum can be fit by a power law with a photon index of 1.94(+-0.02) affected by absorption from cool material with a hydrogen column density of 0.401(+-0.007)*10^22 cm^-…
We have analyzed in a systematic way about nine years of INTEGRAL data (17-100 keV) focusing on Supergiant Fast X-ray Transients (SFXTs) and three classical High Mass X-ray Binaries (HMXBs). Our approach has been twofold: image based analysis, sampled over a ~ks time frame to investigate the long-term properties of the sources, and lightcurve based analysis, sampled over a 100s time frame to seize the fast variability of each source during its ~ks activity. We find that while the prototypical SFXTs (IGR J17544-2619, XTE J1739-302 and SAX J1818.6-1703) are among the sources with the lowest ~ks …
The High Energy Stereoscopic System (H.E.S.S.) observatory has carried a deep survey of the Galactic plane, in the course of which the existence of a significant number of ($\sim$ 78) TeV $γ$-ray sources was confirmed, many of which remain unidentified. HESS J1828-099 is a point-like (Gaussian stand. dev. $<$ 0.07$^{\circ}$) unidentified source among the 17 confirmed point-like sources in the H.E.S.S. Galactic Plane Survey (HGPS) catalog. This source is also unique because it does not seem to have any apparent association with any object detected at other wavelengths. We investigate the nature…
BH-NS and BH-BH systems are among the most promising gravitational wave sources detectable by advanced LIGO/VIRGO and the Einstein Telescope. Although the rates of these systems may be above those of NS-NS mergers, BH-NS and BH-BH systems are difficult to detect, and thusfar none have been observed. But the progenitors of BH-NS and BH-BH binary systems may have been observed, in the form of High-Mass X-ray Binaries (HMXBs). In this paper, we continue work studying these potential progenitors of these important gravitational wave sources. In the first two papers of the series, we have demonstra…
We report the results from pulsations and spectral analysis of a large number of observations of the HMXB pulsar IGR J18027--2016 with {\it Swift}--XRT, carried out at different orbital phases. In some orbital phases, as seen in different XRT observations, the X-ray intensity is found to vary by a large factor, of about $\sim$50. In all the observations with sufficient number of source X-ray photons, pulsations have been detected around the previously known pulse period of $\sim$140 sec, When detected, the pulse profiles do not show any significant variation over a flux difference of a factor …
We report the Chandra/HRC-S and Swift/XRT observations for the 2015 outburst of the high-mass X-ray binary (HMXB) pulsar in the Small Magellanic Cloud, SMC X-2. While previous studies suggested that either an O star or a Be star in the field is the high-mass companion of SMC X-2, our Chandra/HRC-S image unambiguously confirms the O-type star as the true optical counterpart. Using the Swift/XRT observations, we extracted accurate orbital parameters of the pulsar binary through a time of arrivals (TOAs) analysis. In addition, there were two X-ray dips near the inferior conjunction, which are pos…
We report on the results of NuSTAR and XMM-Newton observations of the persistent X-ray source 1E1743.1-2843, located in the Galactic Center region. The source was observed between September and October 2012 by NuSTAR and XMM-Newton, providing almost simultaneous observations in the hard and soft X-ray bands. The high X-ray luminosity points to the presence of an accreting compact object. We analyze the possibilities of this accreting compact object being either a neutron star (NS) or a black hole, and conclude that the joint XMM-Newton and NuSTAR spectrum from 0.3 to 40 $\mathrm{keV}$ fits to …
4U 1538-52 in a Heartbeat: Broadband X-ray Spectral Properties from XMM-Newton and NuSTAR
Univ Toulouse, CNES, CNRS, IRAP（图卢兹大学）；European Space Agency (ESA), European Space Astronomy Centre (ESAC)（欧洲空间局）；Institute for Astronomy & Astrophysics, National Observatory of Athens（雅典国家天文台天体物理学与天文学研究所）；Department of Physics, University of Crete（克里特大学物理系）；Institute of Astronomy, KU Leuven（荷鲁芬大学天文学研究所）；Dr. Karl Remeis Observatory, Bamberg and Erlangen Center for Astroparticle Physics, Friedrich Alexander University Erlangen-Nuernberg（弗里德里希·亚历山大埃尔朗根-纽伦堡大学）；Instituto de Física de Cantabria (CSIC-UC)（坎塔布里亚物理研究所）；Instituto Universitario de Física Aplicada a las Ciencias y las Ingenierías, Universidad de Alicante（阿利坎特大学）；Starion España S.L.U（Starion西班牙有限公司）
The pulsar IGR J16393-4643 belongs to a class of highly absorbed supergiant HMXBs, characterised by very high column density of absorbing matter. We present the results of the simultaneous broad-band pulsation and spectrum analysis, from a 44 kilosec Suzaku observation of the source. The orbital intensity profile created with the SWIFT-BAT light-curve shows an indication of IGR J16393-4643 being an eclipsing system with a short eclipse semi-angle $θ_{E} \sim$ 17$^{\circ}$. For a supergiant companion star with a 20 R$_{\odot}$ radius, this implies an inclination of the orbital plane in the rang…
On MJD 56590-1 (2013 Oct 25-26) observations of the Magellanic Clouds by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observatory discovered a previously-unreported bright, flaring X-ray source. This source was initially given the identification IGR J00569-7226. Subsequent multi-wavelength observations identified the system as new Be/X-ray binary system in the Small Magellanic Cloud. Follow-up X-ray observations by Swift and XMM-Newton revealed an X-ray pulse period of 5.05s and that the system underwent regular occulation/eclipse behaviour every 17d. This is the first report…
Suzaku observations are presented for the high-mass X-ray binaries IGR J16207-5129 and IGR J17391-3021 (=XTE J1739-302). For IGR J16207-5129, we provide the first X-ray broadband (0.5--60 keV) spectrum from which we confirm a large intrinsic column density (nH = 1.6e23 /cm2), and we constrain the cutoff energy for the first time (Ec = 19 keV). A prolonged (> 30 ks) attenuation of the X-ray flux was observed which we tentatively attribute to an eclipse of the probable neutron star by its massive companion, in a binary system with an orbital period between 4 and 9 days, and inclination angles > …
LS I +61 303 and LS 5039 are exceptionally rare examples of HMXBs with MeV-TeV emission, making them two of only five known or proposed "gamma-ray binaries". There has been disagreement within the literature over whether these systems are microquasars, with stellar winds accreting onto a compact object to produce high energy emission and relativistic jets, or whether their emission properties might be better explained by a relativistic pulsar wind colliding with the stellar wind. Here we present an attempt to detect radio pulsars in both systems with the Green Bank Telescope. The upper limits …
Spectral and photometric variability of SS 433 observed with XRISM and simultaneous optical and near-infrared telescopes
Rikkyo University（立教大学）；Kyoto University（京都大学）；Ehime University（爱媛大学）；Tokyo University of Science（东京科学大学）；NASA/Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Shizuoka University（静冈大学）；The Graduate University for Advanced Studies, SOKENDAI（综合研究大学院大学）；National Astronomical Observatory of Japan（日本国立天文台）；Kanagawa University（神奈川大学）；Yamaguchi University（山口大学）；Tokyo Institute of Technology（东京工业大学）；The University of Tokyo（东京大学）；Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA)（日本宇宙航空研究开发机构宇宙科学研究所）；Aoyama Gakuin University（青山学院大学）；Center for Astrophysics | Harvard & Smithsonian（哈佛史密森尼天体物理中心）；University of Florida（佛罗里达大学）；Okayama Observatory, Kyoto University（京都大学冈山观测所）；Kanazawa University（金泽大学）；Kagoshima University（鹿儿岛大学）；The Catholic University of America（美利坚天主教大学）；Kiso Observatory, Institute of Astronomy, Graduate School of Science, The University of Tokyo（东京大学理学研究科天文学系木曾观测所）；Korea Astronomy and Space Science Institute（韩国天文学与空间科学研究所）
