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Sample records for supernovae x-ray binaries

  1. The youngest known X-ray binary: Circinus X-1 and its natal supernova remnant

    SciTech Connect

    Heinz, S.; Sell, P.; Fender, R. P.; Jonker, P. G.; Brandt, W. N.; Calvelo-Santos, D. E.; Tzioumis, A. K.; Nowak, M. A.; Schulz, N. S.; Wijnands, R.; Van der Klis, M.

    2013-12-20

    Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4600 yr on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core-collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets that were thought to power the arcminute-scale radio nebula surrounding the source. Instead, this nebula can now be attributed to non-thermal synchrotron emission from the forward shock of the supernova remnant. The young age is consistent with the observed rapid orbital evolution and the highly eccentric orbit of the system and offers the chance to test the physics of post-supernova orbital evolution in X-ray binaries in detail for the first time.

  2. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    SciTech Connect

    Seward, F. D.; Charles, P. A.; Foster, D. L.; Dickel, J. R.; Romero, P. S.; Edwards, Z. I.; Perry, M.; Williams, R. M.

    2012-11-10

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

  3. PROBING ELECTRON-CAPTURE SUPERNOVAE: X-RAY BINARIES IN STARBURSTS

    SciTech Connect

    Linden, T.; Sepinsky, J. F.; Kalogera, V.; Belczynski, K.

    2009-07-10

    We develop population models of high-mass X-ray binaries (HMXBs) formed after bursts of star formation and we investigate the effect of electron-capture supernovae (ECS) of massive ONeMg white dwarfs and the hypothesis that ECS events are associated with typically low supernova kicks imparted to the nascent neutron stars. We identify an interesting ECS bump in the time evolution of HMXB numbers; this bump is caused by significantly increased production of wind-fed HMXBs 20-60 Myr post-starburst. The amplitude and age extent of the ECS bump depend on the strength of ECS kicks and the mass range of ECS progenitors. We also find that ECS-HMXBs form through a specific evolutionary channel that is expected to lead to binaries with Be donors in wide orbits. These characteristics, along with their sensitivity to ECS properties, provide us with an intriguing opportunity to probe ECS physics and progenitors through studies of starbursts of different ages. Specifically, the case of the Small Magellanic Cloud, with a significant observed population of Be-HMXBs and starburst activity 30-60 Myr ago, arises as a promising laboratory for understanding the role of ECS in neutron star formation.

  4. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  5. A search for X-ray polarization in cosmic X-ray sources. [binary X-ray sources and supernovae remnants

    NASA Technical Reports Server (NTRS)

    Hughes, J. P.; Long, K. S.; Novick, R.

    1983-01-01

    Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission.

  6. Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the Wing of the Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Hénault-Brunet, V.; Oskinova, L. M.; Guerrero, M. A.; Sun, W.; Chu, Y.-H.; Evans, C. J.; Gallagher, J. S., III; Gruendl, R. A.; Reyes-Iturbide, J.

    2012-02-01

    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 NGC 602. We detect a shell nebula around 2dFS 3831 in Hα and [O III] 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) × 104 yr provides a constraint on the age of the pulsar.

  7. X-ray reprocessing in binaries

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit

    2016-07-01

    We will discuss several aspects of X-ray reprocessing into X-rays or longer wavelength radiation in different kinds of binary systems. In high mass X-ray binaries, reprocessing of hard X-rays into emission lines or lower temperature black body emission is a useful tool to investigate the reprocessing media like the stellar wind, clumpy structures in the wind, accretion disk or accretion stream. In low mass X-ray binaries, reprocessing from the surface of the companion star, the accretion disk, warps and other structures in the accretion disk produce signatures in longer wavelength radiation. X-ray sources with temporal structures like the X-ray pulsars and thermonuclear burst sources are key in such studies. We will discuss results from several new investigations of X-ray reprocessing phenomena in X-ray binaries.

  8. Longterm lightcurves of X-ray binaries

    NASA Astrophysics Data System (ADS)

    Clarkson, William

    The X-ray Binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight ( P orb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena, indeed the resulting accretion/ outflow process is among the most efficient energy-conversion machines in the universe. The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves above 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ~3 years' overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X- 1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band. Chapters 1 & 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 & 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE

  9. High Mass X-ray Binary Pulsars

    NASA Astrophysics Data System (ADS)

    Naik, Sachindra

    2016-07-01

    High Mass X-ray Binaries (HMXBs) are interesting objects that provide a wide range of observational probes to the nature of the two stellar components, accretion process, stellar wind and orbital parameters of the systems. Most of the transient HMXBs are found to Be/X-ray binaries (~67%), consisting of a compact object (neutron star) in orbit around the companion Be star. The orbit of the compact object around the Be star is wide and highly eccentric. Be/X-ray binaries are generally quiescent in X-ray emission. The transient X-ray outbursts seen in these objects are known to be due to interaction between the compact object and the circumstellar disk surrounding the Be star. In the recent years, another class of transient HMXBs have been found which have supergiant companions and show shorter X-ray outbursts. X-ray, infrared and optical observations of these HMXBs provide vital information regarding these systems. The timing and broad-band X-ray spectral properties of a few HMXB pulsars, mainly Be/X-ray binary pulsars during regular X-ray outbursts will be discussed.

  10. X-ray imaging - Supernova remnants

    NASA Technical Reports Server (NTRS)

    Helfand, D. J.

    1981-01-01

    Consideration is given to imaging observations of supernova remnants (SNRs) obtained during the first year of the Einstein Observatory's operation. Inferences are drawn regarding models for stellar explosions, remnant evolution, neutron star formation and the interstellar medium. Because the X-ray emission traces the expanding shock boundary and dominates the radiative energy losses of an SNR over much of its lifetime, it can provide data on the possible collapsed remnants of the explosion, such as neutron stars and/or black holes. X-ray emission also allows a supernova shock to be used as a probe of interstellar medium structure. The imaging instrument aboard the Einstein satellite has been used to observe over 30 known Galactic remnants, and a similar number of objects in other galaxies, in the 0.15-4.5 keV band.

  11. X-ray spectra of supernova remnants

    NASA Technical Reports Server (NTRS)

    Szymkowiak, A. E.

    1985-01-01

    X-ray spectra were obtained from fields in three supernova remnants with the solid state spectrometer of the HEAO 2 satellite. These spectra, which contain lines from K-shell transitions of several abundant elements with atomic numbers between 10 and 22, were compared with various models, including some of spectra that would be produced by adiabatic phase remnants when the time-dependence of the ionization is considered.

  12. X-ray binaries in globular clusters

    NASA Technical Reports Server (NTRS)

    Grindlay, Jonathan E.

    1988-01-01

    X-ray and optical studies of compact binaries and globular clusters are reviewed. Topics covered include, the formation of compact binaries by three-body interactions and by tidal capture, studies of the 11 minute binary in NGC 6624 and the 8.5 hour binary in M 15 (AC211), and an evolutionary model for compact binary formation. Optical searches for X-ray binaries in globular clusters are examined including CCD surveys and studies of NGC 6712. In addition, globular clusters with central cusps in their surface brightness profiles, questions concerning the blue color of binaries, diffuse line emission from CVs, and the possibility that X-ray burst sources in the galactic bulge were formed by tidal capture in globular clusters which have since been disrupted are discussed.

  13. Polarisation modulation in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ingram, Adam; Maccarone, Thomas

    2016-07-01

    X-ray polarimetry promises to provide a powerful new lever arm for studying accretion onto black holes with the next generation of X-ray telescopes. I will discuss how polarisation can be used to help constrain the physical origin of quasi-periodic oscillations (QPOs) observed in the X-ray light curves of accreting black holes. QPOs may be signatures of the frame dragging effect: in General Relativity, a spinning black hole twists up the surrounding space-time, causing vertical precession of nearby orbits. In the truncated disc / precessing inner flow model, the entire inner accretion flow precesses as a solid body causing a modulation in the X-ray flux through solid angle and Doppler effects. This model also predicts the observed polarisation of the X-ray signal to vary quasi-periodically. I will summarise our work to model the polarisation signal from a precessing accretion flow, starting with simple assumptions about the emission mechanism but taking General Relativity fully into account. We find that it should be possible to measure the predicted modulation in polarisation degree for a reasonable region of parameter space with a polarimeter capable of detecting ~60 counts per second from a bright black hole binary. I will also show that sensitivity can be greatly improved by correlating the signal with a high count rate reference band signal.

  14. Investigating the X-ray Emission from some of the Oldest Known X-ray Supernovae

    NASA Astrophysics Data System (ADS)

    Dwarkadas, Vikram; Holmes, Danika

    2016-04-01

    The core-collapse of a massive star results in a supernova (SN) explosion, and a shock wave that expands outwards. The evolution of the shock wave, and the radius and morphology of the resulting remnant, depends on the density structure of the SN ejecta and surrounding medium. As the SN evolves, it sweeps up more material. The shock velocity, and therefore post-shock temperature (proportional to the square of the shock velocity), will consequently decrease. Thus we would expect a gradual evolution in the X-ray properties of the SN. While theoretical models anticipate this, very few SNe have observations over several decades that allow us to probe the time evolution of the X-ray emission and SN shocks.We have compiled a database of most observed X-ray SNe. In this talk we will summarize the X-ray data on some of the oldest detected X-ray SNe. These observations bridge the gap between old SNe and young supernova remnants, and shed light on the transition of a supernova to a remnant. We will show lightcurves for those which have multiple detections, outline the variation in their X-ray luminosity with time, compare their X-ray emission to that of younger supernovae, and discuss the evolution of the shock parameters as the supernova continues on its journey towards becoming a remnant.

  15. Spectral Analysis of X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Fridriksson, Joel K.

    2011-09-01

    In this thesis, I present work from three separate research projects associated with observations of X-ray binaries. Two of those revolve around spectral characteristics of neutron star low-mass X-ray binaries (NS-LMXBs), with a particular source, XTE J1701-462, playing a central role. First, I construct and study color-color and hardness-intensity diagrams (CDs and HIDs) for a large sample of NS-LMXBs using Rossi X-ray Timing Explorer (RXTE) data spanning ~15 years. I study in particular detail three sources whose complicated CDs/HIDs are strongly affected by secular motion -- Cyg X-2, Cir X-1, and GX 13+1 -- and show that Cyg X-2 and Cir X-1 display CD/HID evolution with strong similarities to the transient Z source XTE J1701-462, which was previously shown to have evolved through all subclasses of NS-LMXBs as a result of changes in mass accretion rate. I build on the results for XTE J1701-462, Cyg X-2, and Cir X-1 and rank all the sources in the sample based only on their CD/HID morphology. I speculate that this represents a rough ranking in terms of the relative ranges in mass accretion rate experienced by the sources. Next, I use data from RXTE, Swift, Chandra, and XMM-Newton to study the transition to quiescence and the first ~1200 days of the quiescent phase of XTE J1701-462 following the end of its extraordinarily luminous 19 month outburst in 2006-2007. I find that the crust of the neutron star cooled rapidly during the first ~200 days of quiescence, after having been heated out of thermal equilibrium with the core during the outburst; the source has subsequently shown slower cooling along with sporadic low-level accretion activity. I discuss the implications of the observed cooling behavior and low-level accretion, the former of which yields information on the internal properties of the neutron star. Finally, I use multiple Chandra observations to study the X-ray source populations in the late-type galaxies NGC 6946 and NGC 4485/4490. A particular

  16. The attenuation of X-rays emitted by supernovae

    NASA Technical Reports Server (NTRS)

    Schocken, K.

    1973-01-01

    The attenuation of X-rays in Arnett's C-12 detonation supernova model is computed. The attenuation of X-rays in the filaments of the Crab Nebula is computed using a model for the filaments by Woltjer and a model by Davidson and Tucker. An empirical expression by Gorenstein, Kellogg, and Gursky for the optical thickness of the interstellar medium for three supernova remnants is analyzed.

  17. GSFC Contributions to the NATO X-ray Astronomy Institute, Erice, July 1979. [X-ray spectra of supernova remants, galactic X-ray sources, active galactic nuclei, and clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Mushotzky, R. F.

    1979-01-01

    An overview of X-ray astronomical spectroscopy in general is presented and results obtained by HEAO 1 and 2 as well as earlier spacecraft are examined. Particular emphasis is given to the spectra of supernova remnants; galactic binary X-ray sources, cataclysmic variables, bulges, pulsars, and stars; the active nuclei of Seyfert 1 galaxy, BL Lac, and quasars; the diffuse X-ray background; and galactic clusters.

  18. Polarization from Scattering in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Kallman, T.

    2009-01-01

    A paradox of X-ray binaries is that their strong X-ray flux ionizes much nearby low density gas, making it difficult to observe. Polarization can reveal gas which is fully ionized and can provide new insight into X-ray binary environments. In this talk I will present models for the scattering and polarization in X-ray binaries, adopting gas parameters which are chosen according to current ideas about these systems. These include stellar winds from a massive companion, X-ray induced disk winds, and the photospheres of a disk or binary companion.

  19. TYPING SUPERNOVA REMNANTS USING X-RAY LINE EMISSION MORPHOLOGIES

    SciTech Connect

    Lopez, L. A.; Ramirez-Ruiz, E.; Badenes, C.; Huppenkothen, D.; Jeltema, T. E.

    2009-11-20

    We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in 17 Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse supernovae explosions are intrinsically more asymmetric.

  20. Chandra Observations of New X-ray Supernovae

    NASA Astrophysics Data System (ADS)

    Pooley, David

    2012-09-01

    We propose to continue our X-ray studies of all types of supernovae (SNe). The Swift satellite has ushered in a new era of studying SNe in the X-rays, obtaining densely sampled observations for nearby SNe, both core collapse and thermonuclear (although no Type Ia has been conclusively detected in X-rays). However, the Swift XRT spatial resolution is often not good enough to definitively associate X-ray emission in the direction of the SN with the SN itself. We propose short Chandra observations to alleviate this. These observations will assess the X-ray environment of newly discovered X-ray SNe to determine any possible source confusion or contamination of the SN flux. Our strategy makes the best use of the capabilities of each observatory.

  1. Swift X-Ray Telescope Observations of Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Kae Batara Olaes, Melanie; Quimby, Robert

    2016-06-01

    Superluminous Supernovae (SLSNe) are a part of an emerging class of exceptionally bright supernovae with peak luminosities 10 times brighter than typical Type Ia supernovae. Similar to supernovae, SLSNe are divided into two subclasses: hydrogen poor SLSN-I and hydrogen rich SLSN-II. However, the luminosity of these events is far too high to be explained by the models for normal supernovae. New models developed to explain SLSNe predict high luminosity X-ray emission at late times. A consistent analysis of incoming SLSNe is essential in order to place constraints on the mechanisms behind these events. Here we present the results of X-ray analysis on SLSNe using a Bayesian method of statistical inference for low count rate events.

  2. EVOLUTION OF SYNCHROTRON X-RAYS IN SUPERNOVA REMNANTS

    SciTech Connect

    Nakamura, Ryoko; Bamba, Aya; Dotani, Tadayasu; Ishida, Manabu; Kohri, Kazunori

    2012-02-20

    A systematic study of the synchrotron X-ray emission from supernova remnants (SNRs) has been conducted. We selected a total of 12 SNRs whose synchrotron X-ray spectral parameters are available in the literature with reasonable accuracy and studied how their luminosities change as a function of radius. It is found that the synchrotron X-ray luminosity tends to drop especially when the SNRs become larger than {approx}5 pc, despite large scatter. This may be explained by the change of spectral shape caused by the decrease of the synchrotron roll-off energy. A simple evolutionary model of the X-ray luminosity is proposed and is found to reproduce the observed data approximately, with reasonable model parameters. According to the model, the total energy of accelerated electrons is estimated to be 10{sup 47-48} erg, which is well below the supernova explosion energy. The maximum energies of accelerated electrons and protons are also discussed.

  3. Collective Properties of Neutron-star X-Ray Binary Populations of Galaxies. II. Pre-low-mass X-Ray Binary Properties, Formation Rates, and Constraints

    NASA Astrophysics Data System (ADS)

    Bhadkamkar, H.; Ghosh, P.

    2014-04-01

    We continue our exploration of the collective properties of neutron-star X-ray binaries in the stellar fields (i.e., outside globular clusters) of normal galaxies. In Paper I of this series, we considered high-mass X-ray binaries (HMXBs). In this paper (Paper II), we consider low-mass X-ray binaries (LMXBs), whose evolutionary scenario is very different from that of HMXBs. We consider the evolution of primordial binaries up to the stage where the neutron star just formed in the supernova explosion of the primary is in a binary with its low-mass, unevolved companion, and this binary has circularized tidally, producing what we call a pre-low-mass X-ray binary (pre-LMXB). We study the constraints on the formation of such pre-LMXBs in detail (since these are low-probability events), and calculate their collective properties and formation rates. To this end, we first consider the changes in the binary parameters in the various steps involved, viz., the common-envelope phase, the supernova, and the tidal evolution. This naturally leads to a clarification of the constraints. We then describe our calculation of the evolution of the distributions of primordial binary parameters into those of pre-LMXB parameters, following the standard evolutionary scenario for individual binaries. We display the latter as both bivariate and monovariate distributions, discuss their essential properties, and indicate the influences of some essential factors on these. Finally, we calculate the formation rate of these pre-LMXBs. The results of this paper will be used in a subsequent one to compute the expected X-ray luminosity function of LMXBs.

  4. Be/X-ray Binary Science for Future X-ray Timing Missions

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    For future missions, the Be/X-ray binary community needs to clearly define our science priorities for the future to advocate for their inclusion in future missions. In this talk, I will describe current designs for two potential future missions and Be X-ray binary science enabled by these designs. The Large Observatory For X-ray Timing (LOFT) is an X-ray timing mission selected in February 2011 for the assessment phase from the 2010 ESA M3 call for proposals. The Advanced X-ray Timing ARray (AXTAR) is a NASA explorer concept X-ray timing mission. This talk is intended to initiate discussions of our science priorities for the future.

  5. The superslow pulsation X-ray pulsars in high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Wang, Wei

    2013-03-01

    There exists a special class of X-ray pulsars that exhibit very slow pulsation of P spin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (P spin ~ 5560 s with Ṗ spin ~ 4.9 × 10-7 s s-1) and long-term spin-up trend for 2S 0114+65 (P spin ~ 9600 s with Ṗ spin ~ -1 × 10-6 s s-1) in the last 20 years. A Be X-ray transient, SXP 1062 (P spin ~ 1062 s), also showed a fast spin-down rate of Ṗ spin ~ 3 × 10-6 s s-1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system - accreting magnetars.

  6. Young Supernova explosions in the X-rays and hard X-rays

    NASA Astrophysics Data System (ADS)

    Margutti, Raffaella

    2016-04-01

    X-ray observations are providing critical insights into Supernova explosions and the nature of their progenitors. In this talk I will highlight some recent results from our dedicated programs at high-energies that allowed us to (1) uncover the weakest engine-driven SNe and understand their link to Gamma-Ray Bursts; (2) monitor the high-energy emission from shock energy deposition into the stellar envelope as early as a few days after the onset of core-collapse; (3) put the most stringent constraints to the progenitors of Type Ia SNe by using the deepest X-ray observations ever obtained. (4) Reveal the ejection of a massive stellar envelope timed with the collapse of a stripped star. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays of ˜40 keV

  7. Correlated X-ray and optical variability in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    O'Brien, K.; Horne, K.

    In X-ray binaries much of the optical/UV emission arises from X-rays reprocessed by material in the accretion disk, stream and the companion star. The resulting optical variability will be delayed in time with respect to the X-ray variability depending on the position of the reprocessing regions in the binary system. By deconvolving the X-ray and optical variability we can determine a range of time-delays present in the system. This time-delay transfer function can be used to echo-map the geometry of the reprocessing regions in the binary system. We present results from our echo-mapping campaign using X-ray lightcurves from RXTE, simultaneous with high time resolution optical and UV observations. In the SXT, GRO J1655-40, using RXTE and HST shortly after the 1996 outburst, we find evidence for reprocessing in the outer regions of a thick accretion disk. In the Z-source Cygnus X-2, using RXTE and Keck II, we find an anti-correlation of the X-ray and optical variability on the timescale of hours, with superimposed correlated X-ray and optical flaring.

  8. Recurring X-ray outbursts in the supernova impostor SN 2010da in NGC 300

    NASA Astrophysics Data System (ADS)

    Binder, B.; Williams, B. F.; Kong, A. K. H.; Gaetz, T. J.; Plucinsky, P. P.; Skillman, E. D.; Dolphin, A.

    2016-04-01

    We present new observations of the `supernova impostor' SN 2010da using the Chandra X-ray Observatory and the Hubble Space Telescope. During the initial 2010 outburst, the 0.3-10 keV luminosity was observed by Swift to be ˜5 × 1038 erg s-1 and faded by a factor of ˜25 in a four month period. Our two new Chandra observations show a factor of ˜10 increase in the 0.35-8 keV X-ray luminosity, from ˜4 × 1036 to 4 × 1037 erg s-1 in ˜6 months, and the X-ray spectrum is consistent in both observations with a power-law with a photon index of Γ ˜ 0. We find evidence of X-ray spectral state changes: when SN 2010da is in a high-luminosity state, the X-ray spectrum is harder (Γ ˜0) compared to the low-luminosity state (Γ ˜ 1.2 ± 0.8). Using our Hubble observations, we fit the colour-magnitude diagram of the coeval stellar population to estimate a time since formation of the SN 2010da progenitor system of ≲5 Myr. Our observations are consistent with SN 2010da being a high-mass X-ray binary (HMXB) composed of a neutron star and a luminous blue variable-like companion, although we cannot rule out the possibility that SN 2010da is an unusually X-ray bright massive star. The ≲5 Myr age is consistent with the theoretically predicted delay time between the formation of a massive binary and the onset of the HMXB phase. It is possible that the initial 2010 outburst marked the beginning of X-ray production in the system, making SN 2010da possibly the first massive progenitor binary ever observed to evolve into an HMXB.

  9. Gamma-Ray Emission from X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Shrader, Chris R.

    2007-01-01

    We summarize the current observational picture regarding high-energy emission from Galactic X-ray binaries, reviewing the results of the Compton Gamma Ray Observatory mission. We speculate on the prospects for the GLAST era.

  10. The X-ray surface brightness of Kepler's supernova remnant

    NASA Technical Reports Server (NTRS)

    White, R. L.; Long, K. S.

    1983-01-01

    The first X-ray images of Kepler's supernova remnant (SN Ophiuchi 1604) are presented, and consequences for SNR models are discussed. Observations made with the Einstein Observatory Imaging Proportional Counter and High Resolution Imager show the remnant to be circular, with a strong shell brighter in the north than in the south. A flux of 1.2 x 10 to the -10th ergs/sq cm per sec was measured in the 0.15-4.5 keV region, which corresponds to an X-ray luminosity of 1.0 x 10 to the 36th ergs/sec at a distance of 5 kpc and an interstellar medium density of 2.8 x 10 to the 21st/sq cm. The X-ray observations do not allow the determination of whether the SNR is in the adiabatic or free expansion phase, but in either case it is shown that the mean ISM density must be greater than about 0.1/cu cm. In addition, the density of the X-ray emitting gas must be high, and its electron temperature must be fairly low. The high ISM densities derived for Kepler's SNR and other SNRs thus suggest an atypical ISM, possibly influenced by mass lost from the pre-supernova star.

  11. X-ray Evidence Supports Possible New Class Of Supernova

    NASA Astrophysics Data System (ADS)

    2007-01-01

    Evidence for a significant new class of supernova has been found with NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton. These results strengthen the case for a population of stars that evolve rapidly and are destroyed by thermonuclear explosions. Such "prompt" supernovas could be valuable tools for probing the early history of the cosmos. A team of astronomers uncovered a puzzling situation when they examined X-ray data from DEM L238 and DEM L249, the remnants of two supernovas in a nearby galaxy. On the one hand, the unusually high concentration of iron atoms implied that the remnants are the products of thermonuclear explosions of white dwarf stars, a well-known type of supernova known as Type Ia. On the other hand, the hot gas in the remnants was much denser and brighter in X-rays than typical Type Ia remnants. A white dwarf, the dense final stage in the evolution of a sun-like star, is a very stable object and will not explode on its own. However, if a white dwarf has a close companion star it can grow beyond a critical mass by pulling gas off the companion and explode. Chandra X-ray and MCELS Optical Image of DEM L238 and DEM L249 Chandra X-ray and MCELS Optical Image of DEM L238 and DEM L249 Computer simulations of Type Ia supernova remnants showed that the most likely explanation for the X-ray data is that the white dwarfs exploded into very dense environments. This suggests that the stars which evolved into these white dwarfs were more massive than usual, because heavier stars are known to expel more gas into their surroundings. "We know that the more massive a star is, the shorter its lifetime," said Kazimierz Borkowski of North Carolina State University, Raleigh. "If such a star could also begin to pull matter from its companion at an early stage, then this star would have a much shorter fuse and explode in only about 100 million years -- much less than other Type Ia supernovas." Other teams have independently found evidence for

  12. The X-Ray Spectral Evolution of Galactic Black Hole X-Ray Binaries toward Quiescence

    NASA Astrophysics Data System (ADS)

    Plotkin, Richard. M.; Gallo, Elena; Jonker, Peter G.

    2013-08-01

    Most transient black hole X-ray binaries (BHXBs) spend the bulk of their time in a quiescent state, where they accrete matter from their companion star at highly sub-Eddington luminosities (we define quiescence here as a normalized Eddington ratio lx = L 0.5-10 keV/L Edd < 10-5). Here, we present Chandra X-ray imaging spectroscopy for three BHXB systems (H 1743-322, MAXI J1659-152, and XTE J1752-223) as they fade into quiescence following an outburst. Multiple X-ray observations were taken within one month of each other, allowing us to track each individual system's X-ray spectral evolution during its decay. We compare these three systems to other BHXB systems. We confirm that quiescent BHXBs have softer X-ray spectra than low-hard-state BHXBs, and that quiescent BHXB spectral properties show no dependence on the binary system's orbital parameters. However, the observed anti-correlation between X-ray photon index (Γ) and lx in the low-hard state does not continue once a BHXB enters quiescence. Instead, Γ plateaus to an average langΓrang = 2.08 ± 0.07 by the time lx reaches ~10-5. lx ~ 10-5 is thus an observationally motivated upper limit for the beginning of the quiescent spectral state. Our results are discussed in the context of different accretion flow models and across the black hole mass scale.

  13. Superluminous X-Rays from a Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Levan, A. J.; Read, A. M.; Metzger, B. D.; Wheatley, P. J.; Tanvir, N. R.

    2013-07-01

    The discovery of a population of superluminous supernovae (SLSNe), with peak luminosities a factor of ~100 brighter than normal supernovae (SNe; typically SLSNe have MV < -21), has shown an unexpected diversity in core-collapse SN properties. Numerous models have been postulated for the nature of these events, including a strong interaction of the shockwave with a dense circumstellar environment, a re-energizing of the outflow via a central engine, or an origin in the catastrophic destruction of the star following a loss of pressure due to pair production in an extremely massive stellar core (so-called pair instability SNe). Here we consider constraints that can be placed on the explosion mechanism of hydrogen-poor SLSNe (SLSNe-I) via X-ray observations, with XMM-Newton, Chandra, and Swift, and show that at least one SLSN-I is likely the brightest X-ray SN ever observed, with LX ~ 1045 erg s-1, ~150 days after its initial discovery. This is a luminosity three orders of magnitude higher than seen in other X-ray SNe powered via circumstellar interactions. Such high X-ray luminosities are sufficient to ionize the ejecta and markedly reduce the optical depth, making it possible to see deep into the ejecta and any source of emission that resides there. Alternatively, an engine could have powered a moderately relativistic jet external to the ejecta, similar to those seen in gamma-ray bursts. If the detection of X-rays does require an engine it implies that these SNe do create compact objects, and that the stars are not completely destroyed in a pair instability event. Future observations will determine which, if any, of these mechanisms are at play in SLSNe.

  14. INVERSE COMPTON X-RAY EMISSION FROM SUPERNOVAE WITH COMPACT PROGENITORS: APPLICATION TO SN2011fe

    SciTech Connect

    Margutti, R.; Soderberg, A. M.; Chomiuk, L.; Milisavljevic, D.; Foley, R. J.; Slane, P.; Moe, M.; Chevalier, R.; Hurley, K.; Hughes, J. P.; Fransson, C.; Barthelmy, S.; Cummings, J.; Briggs, M.; Connaughton, V.; Costa, E.; Del Monte, E. [INAF and others

    2012-06-01

    We present a generalized analytic formalism for the inverse Compton X-ray emission from hydrogen-poor supernovae and apply this framework to SN 2011fe using Swift X-Ray Telescope (XRT), UVOT, and Chandra observations. We characterize the optical properties of SN 2011fe in the Swift bands and find them to be broadly consistent with a 'normal' SN Ia, however, no X-ray source is detected by either XRT or Chandra. We constrain the progenitor system mass-loss rate M-dot < 2 x 10{sup -9} M{sub Sun }yr{sup -1} (3{sigma} c.l.) for wind velocity v{sub w} = 100 km s{sup -1}. Our result rules out symbiotic binary progenitors for SN 2011fe and argues against Roche lobe overflowing subgiants and main-sequence secondary stars if {approx}> 1% of the transferred mass is lost at the Lagrangian points. Regardless of the density profile, the X-ray non-detections are suggestive of a clean environment (n{sub CSM} < 150 cm{sup -3}) for 2 Multiplication-Sign 10{sup 15} {approx}< R {approx}< 5 Multiplication-Sign 10{sup 16} cm around the progenitor site. This is either consistent with the bulk of material being confined within the binary system or with a significant delay between mass loss and supernova explosion. We furthermore combine X-ray and radio limits from Chomiuk et al. to constrain the post-shock energy density in magnetic fields. Finally, we searched for the shock breakout pulse using gamma-ray observations from the Interplanetary Network and find no compelling evidence for a supernova-associated burst. Based on the compact radius of the progenitor star we estimate that the shock breakout pulse was likely not detectable by current satellites.

  15. X-ray Evidence Supports Possible New Class Of Supernova

    NASA Astrophysics Data System (ADS)

    2007-01-01

    Evidence for a significant new class of supernova has been found with NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton. These results strengthen the case for a population of stars that evolve rapidly and are destroyed by thermonuclear explosions. Such "prompt" supernovas could be valuable tools for probing the early history of the cosmos. A team of astronomers uncovered a puzzling situation when they examined X-ray data from DEM L238 and DEM L249, the remnants of two supernovas in a nearby galaxy. On the one hand, the unusually high concentration of iron atoms implied that the remnants are the products of thermonuclear explosions of white dwarf stars, a well-known type of supernova known as Type Ia. On the other hand, the hot gas in the remnants was much denser and brighter in X-rays than typical Type Ia remnants. A white dwarf, the dense final stage in the evolution of a sun-like star, is a very stable object and will not explode on its own. However, if a white dwarf has a close companion star it can grow beyond a critical mass by pulling gas off the companion and explode. Chandra X-ray and MCELS Optical Image of DEM L238 and DEM L249 Chandra X-ray and MCELS Optical Image of DEM L238 and DEM L249 Computer simulations of Type Ia supernova remnants showed that the most likely explanation for the X-ray data is that the white dwarfs exploded into very dense environments. This suggests that the stars which evolved into these white dwarfs were more massive than usual, because heavier stars are known to expel more gas into their surroundings. "We know that the more massive a star is, the shorter its lifetime," said Kazimierz Borkowski of North Carolina State University, Raleigh. "If such a star could also begin to pull matter from its companion at an early stage, then this star would have a much shorter fuse and explode in only about 100 million years -- much less than other Type Ia supernovas." Other teams have independently found evidence for

  16. Colliding Wind Binary X-ray Sources

    NASA Astrophysics Data System (ADS)

    Corcoran, Michael F.; Hamaguchi, Kenji; Pollock, A. M. T.; Pittard, J. M.; Stevens, I. R.; Henley, D. B.; Moffat, A. F. J.; Marchenko, S.

    Very massive stars (≳ 20 M⊙) are rare but important components of galaxies. Products of core nucleosynthesis from these stars are distributed into the circumstellar environment via wind-driven mass loss. Explosive nucleosynthesis after core collapse further enriches the galactic medium. Clusters of such stars can produce galactic chimneys which can pierce the galactic disk and chemically enrich intergalactic space. Such processes are vitally important to the chemical evolution of the early Universe, when the stellar mass function was much more weighted to massive stars.Very massive stars are difficult to study, since they are formed in distant clusters which yield problems of sensitivity and source crowding. A relatively new tool for studying these systems is via high spatial, spectral and temporal resolution observations in the X-ray band. In this note we describe some recent progress in studying mechanisms by which very massive stars produce X-ray emission.

  17. The missing Wolf-Rayet X-ray binary systems

    NASA Astrophysics Data System (ADS)

    Munoz, M.; Moffat, A. F. J.; Hill, G. M.; Richardson, N. D.; Pablo, H.

    We investigate the rarity of the Wolf-Rayet X-ray binaries (WRXRBs) in contrast to their predecessors, the high mass X-ray binaries (HMXRBs). Recent studies suggest that common envelope (CE) mergers during the evolution of a HMXRBs may be responsible (Linden et al. 2012). We conduct a binary population synthesis to generate a population of HMXRBs mimicking the Galactic sample and vary the efficiency parameter during the CE phase to match the current WRXRB to HMXRB ratio. We find that ˜50% of systems must merge to match observational constraints.

  18. Accretion Disk Dynamics in X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Schulz, Norbert S.; Ji, Li; Nowak, M.; Canizares, C. R.; Kallman, T.

    2009-09-01

    The last decade of X-ray observations was an era of true discovery in the study of accretion phenomena in X-ray binaries. With the launch of high resolution X-ray spectrometers on board the Chandra X-ray Observatory and XMM Newton we gained novel insights in feedback processes in accretion disks. At the forefront are dynamics in winds and outflows. Recent observations now also not only reveal properties of accretion disk coronal phenomena but point us to highly variable activity in their appearance. Amongst others these include heating along the spectral branches in the Z-source Cyg X-2, short and longterm variations in the photo-ionized emissions in Cir X-1, highly variable and dynamic Ne edges in the ultra-compact binary 4U 0614+091. This presentation summarizes these recent developments and provides an outlook towards more dynamical accretion disk coronal models and perspectives for future missions.

  19. X-ray binaries and black hole candidates: a review of optical properties

    NASA Astrophysics Data System (ADS)

    Casares, Jorge

    This chapter summarizes the optical properties of X-ray binaries, with special emphasis on the class of low mass X-ray binaries and soft X-ray transients. The latter provide the most compelling evidence for the existence of black holes in the Universe, with nine well-established dynamical studies. We review the techniques employed to extract the component masses and discuss the importance of systematic effects. Despite the growing number of black hole cases, the uncertainties involved are still too large to draw statistical conclusions on the mass distribution of collapsed objects. We also present new observational techniques which may help to improve the mass determinations and set constraints on the theory of supernovae and black hole formation.

  20. Observations and Models of X-ray binaries

    NASA Astrophysics Data System (ADS)

    Dubus, Guillaume

    1998-06-01

    This PhD thesis presents X-ray observations of the nearby galaxy M33 and an X-ray irradiated accretion disk model. X-ray observations of nearby galaxies allow direct access to the underlying high energy populations, amongst which are X-ray binaries where a compact object (black hole, neutron star) accretes matter from its normal star companion. I present a catalogue and a variability analysis of the sources in M33 detected by the X-ray satellite ROSAT. I discuss X-7 which is shown to be an X-ray binary pulsar. Some 70% of the X-ray flux from M33 comes from the nucleus source X-8. I show that the luminosity from this object is modulated on a 106 day period. Additional observations obtained with the Hubble Space Telescope show a bright stellar-like UV source in the center of the nucleus. These observations significantly constrain models of the bright (Lx~1e39 ergs/s) nucleus source which we believe to be a 10 solar mass black hole X-ray binary. Illumination of the accretion disk surrounding the compact object plays a crucial role in such a system. An accretion disk is thermally and viscously unstable around the hydrogen ionisation temperature. This instability is thought to power the outbursts of dwarf novae and soft X-ray transients. I present a numerical code that can follow the evolution of the instability in a disk with high precision. This model is modified to account for illumination. Contrary to observations of low mass X-ray binaries, illumination by a point source does not modify the properties of a planar disk. However, if the illumination source is not in the disk plane, as is the case for instance if the disk is warped or if the source is above the disk, illumination can stabilise the disk. It is concluded that the physical processes and the geometry of illumination in low mass X-ray binaries is still ill-understood.

  1. Evaporative winds in X-ray binaries

    NASA Technical Reports Server (NTRS)

    Basko, M. M.; Suniaev, R. A.; Hatchett, S.; Mccray, R.

    1977-01-01

    Evaporation of gas from the surface of HZ Her by Her X-1 and its implications regarding the mass transfer process are examined further. The powerful soft X-ray flux results in an evaporation rate greater than previous estimates. The evaporative flow is shown to be subsonic at first, with the result that the capture of evaporated gas by Her X-1 may be efficient, and the self-excited wind mechanism is possible. A criterion for stabilization of mass transfer by stellar wind mass loss is derived. Possible mechanisms for the long-period variability of HZ Her are discussed. Evaporative winds are also estimated for Sco X-1 and Cyg X-2 spectra.

  2. THE X-RAY SPECTRAL EVOLUTION OF GALACTIC BLACK HOLE X-RAY BINARIES TOWARD QUIESCENCE

    SciTech Connect

    Plotkin, Richard M.; Gallo, Elena; Jonker, Peter G.

    2013-08-10

    Most transient black hole X-ray binaries (BHXBs) spend the bulk of their time in a quiescent state, where they accrete matter from their companion star at highly sub-Eddington luminosities (we define quiescence here as a normalized Eddington ratio l{sub x} = L{sub 0.5-10{sub keV}}/L{sub Edd} < 10{sup -5}). Here, we present Chandra X-ray imaging spectroscopy for three BHXB systems (H 1743-322, MAXI J1659-152, and XTE J1752-223) as they fade into quiescence following an outburst. Multiple X-ray observations were taken within one month of each other, allowing us to track each individual system's X-ray spectral evolution during its decay. We compare these three systems to other BHXB systems. We confirm that quiescent BHXBs have softer X-ray spectra than low-hard-state BHXBs, and that quiescent BHXB spectral properties show no dependence on the binary system's orbital parameters. However, the observed anti-correlation between X-ray photon index ({Gamma}) and l{sub x} in the low-hard state does not continue once a BHXB enters quiescence. Instead, {Gamma} plateaus to an average ({Gamma}) = 2.08 {+-} 0.07 by the time l{sub x} reaches {approx}10{sup -5}. l{sub x} {approx} 10{sup -5} is thus an observationally motivated upper limit for the beginning of the quiescent spectral state. Our results are discussed in the context of different accretion flow models and across the black hole mass scale.

  3. X-ray spectroscopy of low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Juett, Adrienne Marie

    2004-10-01

    I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first part of this thesis concentrates on results from the subset of LMXBs with orbital periods less than an hour, known as ultracompact binaries. Previous low- resolution X-ray spectra of four systems (4U 0614+091, 2S 0918-549, 4U 1543-624, and 4U 1850-087) all contain a broad residual near 0.7 keV which had been attributed to unresolved line emission. I show that this residual is due to an incorrect model of the intervening photoelectric absorption and can be accounted for by allowing a non-standard Ne/O abundance ratio in the intervening material. I propose that there is neon-rich material local to each binary and that the mass donor is a low-mass, neon-rich degenerate dwarf in an ultracompact binary. Follow-up spectroscopy of 2S 0918-549 and 4U 1543-624 with the High Energy Transmission Grating Spectrometer (HETGS) onboard Chandra and the Reflection Grating Spectrometer onboard XMM confirms the excess neutral neon absorption. Interestingly, the Ne/O ratio of 4U 1543-624 varies by a factor of three between the Chandra and XMM observations, supporting the suggestion that some of the absorption originates local to the binaries. I also present X-ray spectroscopy of another ultracompact binary, the accretion-powered millisecond pulsar XTE J0929-314. No emission or absorption features are found in the high-resolution spectrum of this source, and the neutral absorption edge depths are consistent with the estimated interstellar absorption. The second part of this thesis uses LMXBs as probes of the interstellar medium (ISM). High-resolution X-ray studies of ISM absorption features can provide measurements of the relative abundances and ionization fractions of all the elements from carbon through iron. X-ray studies also probe the ISM on larger scales than is

  4. Echo Tomography of Reprocessing Sites in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Patterson, Joseph; Haswell, Carole

    1998-01-01

    We discovered correlated rapid variability between the optical/UV and X-ray emission for the first time in a soft X-ray transient, GRO J1655-40. Hubble Space Telescope light curves show features similar to those seen by the Rossi X-ray Timing Explorer, but with a mean delay of up to 10 - 20 s. We interpret the correlation as the result of reprocessing of X-rays into optical and UV emission, with a delay owing to finite light travel time; this assumption enables us to perform echo mapping of the system. The time-delay distribution has a mean of 14.6 +/-1.4 s and a dispersion of 10.5+/-1.9 s at binary phase 0.4. This establishes that the reprocessing region is the accretion disk around the compact star, rather than the mass-donating secondary. These results have been published.

  5. Accretion disk dynamics in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Peris, Charith Srian

    Accreting X-ray binaries consist of a normal star which orbits a compact object with the former transferring matter onto the later via an accretion disk. These accretion disks emit radiation across the entire electromagnetic spectrum. This thesis exploits two regions of the spectrum, exploring the (1) inner disk regions of an accreting black hole binary, GRS1915+105, using X-ray spectral analysis and (2) the outer accretion disks of a set of neutron star and black hole binaries using Doppler Tomography applied on optical observations. X-ray spectral analysis of black hole binary GRS1915+105: GRS1915+105 stands out as an exceptional black hole primarily due to the wild variability exhibited by about half of its X-ray observations. This study focused on the steady X-ray observations of the source, which were found to exhibit significant curvature in the harder coronal component within the RXTE/PCA band-pass. The roughly constant inner-disk radius seen in a majority of the steady-soft observations is strongly reminiscent of canonical soft state black-hole binaries. Remarkably, the steady-hard observations show the presence of growing truncation in the inner-disk. A majority of the steady observations of GRS1915+105 map to the states observed in canonical black hole binaries which suggests that within the complexity of this source is a simpler underlying basis of states. Optical tomography of X-ray binary systems: Doppler tomography was applied to the strong line features present in the optical spectra of X-ray binaries in order to determine the geometric structure of the systems' emitting regions. The point where the accretion stream hits the disk, also referred to as the "hotspot'', is clearly identified in the neutron star system V691 CrA and the black hole system Nova Muscae 1991. Evidence for stream-disk overflows exist in both systems, consistent with relatively high accretion rates. In contrast, V926 Sco does not show evidence for the presence of a hotspot which

  6. Very faint X-ray binaries with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Armas Padilla, M.

    2016-06-01

    A population of very faint X-ray binaries has been discovered in the last years thanks to the improvement in sensitivity and resolution of the new generations of X-ray missions. These systems show anomalously low luminosities, below 10^{36} ergs/sec, challenging our understanding of accretion physics and binary evolution models, and thereby opening new windows for both observational and theoretical work on accretion onto compact objects. XMM-Newton is playing a crucial role in the study of this dim family of objects thanks to its incomparable spectral capabilities at low luminosities. I will review the state-of-the-art of the field and present our XMM results in both black hole and neutron star objects. Finally, I will discuss the possibilities that the new generation of X-ray telescopes offer for this research line.

  7. Masses and Luminosities of X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Quirrenbach, Andreas; Frink, Sabine; Tomsick, John

    2004-01-01

    Using SIM, we will perform narrow-angle observations of several X-ray binaries to determine their orbits, and we will observe about 50 X-ray binary systems in wide-angle mode to measure their distances and proper motions. Sources with mass estimates for the compact component of greater than 3 solar masses are generally called black hole candidates since this mass is above the theoretical neutron star limit. Narrow-angle observations of these sources provide a direct test of the dynamical mass estimates on which the black hole evidence is based. Better measurements of the black hole masses will provide constraints on possible evolutionary paths that lead to black hole formation. When combined with X-ray data, mass measurements may provide additional constraints on the black hole spin. Precise mass determinations of neutron star systems can address the question of whether neutron stars can be significantly more massive than 1.4 solar masses, which would eliminate soft models of the neutron star equations of state. The wide-angle observations will probe the Galactic distribution of X-ray binaries through parallaxes and proper motions. They will also eliminate the uncertainties in the luminosities of individual sources, which is currently up to a full order of magnitude. This will enable more detailed comparisons of X-ray observations to physical models such as advection-dominated accretion flows (ADAFs). We intend to carry out the following measurements: 1) Determine the orbits of two black hole candidates to measure the black hole masses; 2) Obtain precise mass measurements for two neutron star systems to constrain neutron star equations of state; 3) Determine the distances and thus luminosities of selected representatives of various classes of X-ray binaries (black hole candidates, neutron stars, jet sources); 4) In the process of distance determination, proper motions will also be measured, from which the age of the population can be estimated.

  8. Progenitor constraints for core-collapse supernovae from Chandra X-ray observations

    NASA Astrophysics Data System (ADS)

    Heikkilä, T.; Tsygankov, S.; Mattila, S.; Eldridge, J. J.; Fraser, M.; Poutanen, J.

    2016-03-01

    The progenitors of hydrogen-poor core-collapse supernovae (SNe) of Types Ib, Ic and IIb are believed to have shed their outer hydrogen envelopes either by extremely strong stellar winds, characteristic of classical Wolf-Rayet stars, or by binary interaction with a close companion star. The exact nature of the progenitors and the relative importance of these processes are still open questions. One relatively unexplored method to constrain the progenitors is to search for high-mass X-ray binaries (HMXBs) at SN locations in pre-explosion X-ray observations. In an HMXB, one star has already exploded as a core-collapse SN, producing a neutron star or a stellar mass black hole. It is likely that the second star in the system will also explode as an SN, which should cause a detectable long-term change in the system's X-ray luminosity. In particular, a pre-explosion detection of an HMXB coincident with an SN could be informative about the progenitor's nature. In this paper, we analyse pre-explosion ACIS observations of 18 nearby Type Ib, Ic and IIb SNe from the Chandra X-ray observatory public archive. Two sources that could potentially be associated with the SN are identified in the sample. Additionally we make similar post-explosion measurements for 46 SNe. Although our modelling indicates that progenitor systems with compact binary companions are probably quite rare, studies of this type can in the future provide more stringent constraints as the number of discovered nearby SNe and suitable pre-explosion X-ray data are both increasing.

  9. GIANT OUTBURSTS IN Be/X-RAY BINARIES

    SciTech Connect

    Martin, Rebecca G.; Nixon, Chris; Armitage, Philip J.; Lubow, Stephen H.; Price, Daniel J.

    2014-08-01

    Be/X-ray binary systems exhibit both periodic (Type I) X-ray outbursts and giant (Type II) outbursts, whose origins have remained elusive. We suggest that Type II X-ray outbursts occur when a highly misaligned decretion disk around the Be star becomes eccentric, allowing the compact object companion to capture a large amount of material at periastron. Using three-dimensional smoothed particle hydrodynamics simulations, we model the long-term evolution of a representative Be/X-ray binary system. We find that periodic (Type I) X-ray outbursts occur when the neutron star is close to periastron for all disk inclinations. Type II outbursts occur for large misalignment angles and are associated with eccentricity growth which occurs on a timescale of about 10 orbital periods. Mass capture from the eccentric decretion disk results in an accretion disk around the neutron star whose estimated viscous time is long enough to explain the extended duration of Type II outbursts. Previous studies suggested that the outbursts are caused by a warped disk but our results suggest that this is not sufficient; the disk must be both highly misaligned and eccentric to initiate a Type II accretion event.

  10. XMM Observations of X-Ray Emission from Supernovae

    NASA Technical Reports Server (NTRS)

    Immler, Stefan; Lewin, Walter

    2003-01-01

    Of the six proposed targets, only one observation was performed. The observation resulted in a 28ks observation of SN 1998S. At the time of writing the proposal, our target list only contained previously unknown X-ray supernovae. Between submission of the proposal and the actual observation, a Chandra DDT observation resulted in the detection of SN 1998S. Since SN 1998S was observed with Chandra five times before the XMM-Newton observation was made, the data did not yield enough new information to warrant a separate SN 1998S publication. The key science results of that observation were presented in a review article (by Immler and Lewin); the results were also presented at two conferences.

  11. X-ray observations of possible binary clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Ulmer, M. P.; Cruddace, R. G.; Kowalski, M. P.

    1985-01-01

    Many studies of superclusters of galaxies have been conducted, taking into account also superclusters representing candidate binary cluster systems. The present investigation is concerned with further studies of potential binary cluster systems, giving attention to a sample of six cluster pairs, in which the redshifts and X-ray luminosities of each member of a pair have been measured. One of the objectives of the investigation was related to a search for X-ray evidence that the clusters interact in these potentially binary systems. A second objective was to provide a measure of the mass of hot gas in the clusters. Two new systems in which the two clusters may have a physical association were found.

  12. The Be X-ray Binary Outburst Zoo II

    NASA Astrophysics Data System (ADS)

    Kuehnel, M.; Kretschmar, P.; Nespoli, E.; Okazaki, A. T.; Schoenherr, G.; Wilson-Hodge, C. A.; Falkner, S.; Brand, T.; Anders, F.; Schwarm, F.-W.; Kreykenbohm, I.; Mueller, S.; Pottschmidt, K.; Fuerst, F.; Grinberg, V.; Wilms, J.

    2015-03-01

    We have continued our recently started systematic study of Be X-ray binary (BeXRB) outbursts. Specifically, we are developing a catalogue of outbursts including their basic properties based on nearly all available X-ray all-sky-monitors. These properties are derived by fitting asymmetric Gaussians to the outburst lightcurves. This model describes most of the outbursts covered by our preliminary catalogue well; only 13% of all datasets show more complex outburst shapes. Analyzing the basic properties, we reveal a strong correlation between the outburst length and the reached peak flux. As an example, we discuss possible models describing the observed correlation in EXO 2030+375.

  13. X-Ray Line Spectroscopy of Massive X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Liedahl, D. A.; Sako, M.; Wojdowski, P. S.; Paerels, F.; Kahn, S. M.

    2000-01-01

    Spectra from ASCA have provided the most, detailed view to date of the X-ray spectral properties of stellar winds in massive X-ray binaries. Using detailed atomic models that account for recombination cascade kinetics, we have reexamined archival data from Vela X-1 and Cen X-3 in the context of simple models of their wind geometries and velocity distributions. Our approach emphasizes apparent differential emission measure (DEM) distributions, and their dependence on orbital phase and wind parameters. A grid of theoretical DEM distributions is used to generate model spectra, which are compared to the data. We obtain good fits, and derive constraints oil the stellar wind parameters. We provide a summary of the method, and show that, even though the companion stars in Vela X-1 and Cen X-3 have comparable mass-loss rates, the winds in these two systems are dramatically different, in character.

  14. High ionisation absorption in low mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; De, K.; Fender, R.; Merloni, A.

    2016-05-01

    The advent of the new generation of X-ray telescopes yielded a significant step forward in our understanding of ionised absorption generated in the accretion discs of X-ray binaries. It has become evident that these relatively weak and narrow absorption features, sporadically present in the X-ray spectra of some systems, are actually the signature of equatorial outflows, which might carry away more matter than that being accreted. Therefore, they play a major role in the accretion phenomenon. These outflows (or ionised atmospheres) are ubiquitous during the softer states but absent during the power-law dominated, hard states, suggesting a strong link with the state of the inner accretion disc, presence of the radio-jet and the properties of the central source. Here, we discuss the current understanding of this field.

  15. The ASTROSAT mission and study of X-ray binaries.

    NASA Astrophysics Data System (ADS)

    Somasundaram, Seetha

    2016-07-01

    The ASTROnomy SATellite (ASTROSAT) is the first Indian astronomy mission. The scientific objectives to be addressed using ASTROSAT are To understand high energy processes in binary systems containing neutron stars and black hole sources, estimate magnetic fields of neutron stars, study star birth regions and high energy processes in extragalactic systems, and detect new transient X-ray sources. To achieve this ASTROSAT has a suite of experiments to conduct Multiwavelength studies, covering the energy bands in the UV (NUV and FUV), limited optical, and X-ray regime (0.3 keV to 100keV). This will provide wide spectral coverage to study thermal and non-thermal spectra. High resolution timing capability will also enable study of periodic and aperiodic time variabilities in X-ray sources, including high frequency QPOs. This talk will provide a brief description of the instrument capabilities of ASTROSAT and some initial results.

  16. X-Ray Measured Dynamics of Tycho's Supernova Remnant

    NASA Technical Reports Server (NTRS)

    Katsuda, Satoru; Petre, Robert; Hughes, John; Hwang, Una; Yamaguchi, Hiroya; Hayato, Asami; Mori, Koji; Tsunemi, Hiroshi

    2010-01-01

    We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tycho's supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the remnant (i.e., the forward shock and protruding ejecta knots) varies from 0.''20 yr-1 (expansion index m = 0.33, where R = tm ) to 0.''40 yr-1 (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr-1 (m = 0.26) to 0.''40 yr-1 (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of [approx]0.5 are consistent with those derived from radio observations. We also find proper motion and expansion index of the reverse-shocked ejecta to be 0.''21-0.''31 yr-1 and 0.43-0.64, respectively. From a comparison of the measured m-value with Type Ia supernova evolutionary models, we find a pre-shock ambient density around the remnant of [less, similar]0.2 cm-3.

  17. Featured Image: A Supernova Remnant in X-Rays

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    This is a three-color X-ray image taken by Chandra of the supernova remnant RCW 103. This supernova remnant is an unusual system: its young, but unlike other remnants of its age, metal-rich ejecta hadnt previously been discovered in it. In this paper, Kari Frank (Pennsylvania State University) and collaborators analyze the three deepest Chandra observations of RCW 103 and find the first evidence for metal-rich ejecta emission scattered throughout the remnant. Their analyses also help to constrain the identity of the mysterious compact stellar object powering the remnant. In this image, red = 0.30.85 keV, green = 0.851.70 keV, and blue = 1.73.0 keV; click on the image for the full view. For more information and the original image, see the paper here:Kari A. Frank et al 2015 ApJ 810 113 doi:10.1088/0004-637X/810/2/113.

  18. X-RAY EMISSION FROM STRONGLY ASYMMETRIC CIRCUMSTELLAR MATERIAL IN THE REMNANT OF KEPLER'S SUPERNOVA

    SciTech Connect

    Burkey, Mary T.; Reynolds, Stephen P.; Borkowski, Kazimierz J.; Blondin, John M.

    2013-02-10

    Kepler's supernova remnant resulted from a thermonuclear explosion, but is interacting with circumstellar material (CSM) lost from the progenitor system. We describe a statistical technique for isolating X-ray emission due to CSM from that due to shocked ejecta. Shocked CSM coincides well in position with 24 {mu}m emission seen by Spitzer. We find most CSM to be distributed along the bright north rim, but substantial concentrations are also found projected against the center of the remnant, roughly along a diameter with position angle {approx}100 Degree-Sign . We interpret this as evidence for a disk distribution of CSM before the supernova, with the line of sight to the observer roughly in the disk plane. We present two-dimensional hydrodynamic simulations of this scenario in qualitative agreement with the observed CSM morphology. Our observations require Kepler to have originated in a close binary system with an asymptotic giant branch star companion.

  19. Stellar winds in binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Macgregor, K. B.; Vitello, P. A. J.

    1982-01-01

    It is thought that accretion from a strong stellar wind by a compact object may be responsible for the X-ray emission from binary systems containing a massive early-type primary. To investigate the effect of X-ray heating and ionization on the mass transfer process in systems of this type, an idealized model is constructed for the flow of a radiation-driven wind in the presence of an X-ray source of specified luminosity, L sub x. It is noted that for low values of L sub x, X-ray photoionization gives rise to additional ions having spectral lines with wavelengths situated near the peak of the primary continuum flux distribution. As a consequence, the radiation force acting on the gas increases in relation to its value in the absence of X-rays, and the wind is accelerated to higher velocities. As L sub x is increased, the degree of ionization of the wind increases, and the magnitude of the radiation force is diminished in comparison with the case in which L sub x = 0. This reduction leads at first to a decrease in the wind velocity and ultimately (for L sub x sufficiently large) to the termination of radiatively driven mass loss.

  20. Classifying X-Ray Binaries: A Probabilistic Approach

    NASA Astrophysics Data System (ADS)

    Gopalan, Giri; Dil Vrtilek, Saeqa; Bornn, Luke

    2015-08-01

    In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide whether the compact object is a black hole or a neutron star. To assist in this process, we develop a Bayesian statistical model that makes use of the fact that X-ray binary systems appear to cluster based on their compact object type when viewed from a three-dimensional coordinate system derived from X-ray spectral data where the first coordinate is the ratio of counts in the mid- to low-energy band (color 1), the second coordinate is the ratio of counts in the high- to low-energy band (color 2), and the third coordinate is the sum of counts in all three bands. We use this model to estimate the probabilities of an X-ray binary system containing a black hole, non-pulsing neutron star, or pulsing neutron star. In particular, we utilize a latent variable model in which the latent variables follow a Gaussian process prior distribution, and hence we are able to induce the spatial correlation which we believe exists between systems of the same type. The utility of this approach is demonstrated by the accurate prediction of system types using Rossi X-ray Timing Explorer All Sky Monitor data, but it is not flawless. In particular, non-pulsing neutron systems containing “bursters” that are close to the boundary demarcating systems containing black holes tend to be classified as black hole systems. As a byproduct of our analyses, we provide the astronomer with the public R code which can be used to predict the compact object type of XRBs given training data.

  1. Physics of Accretion in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Vrtilek, Saeqa D.

    2004-01-01

    This project consists of several related investigations directed to the study of mass transfer processes in X-ray binaries. Models developed over several years incorporating highly detailed physics will be tested on a balanced mix of existing data and planned observations with both ground and space-based observatories. The extended time coverage of the observations and the existence of {\\it simultaneous} X-ray, ultraviolet, and optical observations will be particularly beneficial for studying the accretion flows. These investigations, which take as detailed a look at the accretion process in X-ray binaries as is now possible, test current models to their limits, and force us to extend them. We now have the ability to do simultaneous ultraviolet/X-ray/optical spectroscopy with HST, Chandra, XMM, and ground-based observatories. The rich spectroscopy that these Observations give us must be interpreted principally by reference to detailed models, the development of which is already well underway; tests of these essential interpretive tools are an important product of the proposed investigations.

  2. X-ray studies of supernova remnants: A different view of supernova explosions

    PubMed Central

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research. PMID:20404206

  3. An X-ray look at the first head-trail nebula in an X-ray binary

    NASA Astrophysics Data System (ADS)

    Soleri, Paolo

    2011-09-01

    Head-tail trails are a common feature in active galactic nuclei and pulsar bow-shocks. Heinz et al. (2008) suggested that also X-ray binaries, being jet sources moving with high velocities in dense media, can leave trails of highly ionized plasma that should be detectable at radio frequencies. During bservations of faint-persistent X-ray binaries, we discovered an optical nebula around the X-ray binary SAX J1712.6-3739, consisting of a bow-shock ring-like nebula in front of the binary and two trails originating close to it. This is the first detection of such structure in a X-ray binary and it opens a new sub-field in the study of these objects. Observations with XMM-Newton and Chandra are now needed to investigate the properties of the surrounding nebula.

  4. An X-ray look at the first head-trail nebula in an X-ray binary

    NASA Astrophysics Data System (ADS)

    Soleri, Paolo

    2010-10-01

    Head-tail trails are a common feature in active galactic nuclei and pulsar bow-shocks. Heinz et al. (2008) suggested that also X-ray binaries, being jet sources moving with high velocities in dense media, can leave trails of highly ionized plasma that should be detectable at radio frequencies. During observations of faint-persistent X-ray binaries, we discovered an optical nebula around the X-ray binary SAX J1712.6-3739, consisting of a bow-shock ring-like nebula ``in front'' of the binary and two trails originating close to it. This is the first detection of such structure in a X-ray binary and it opens a new sub-field in the study of these objects. Observations with XMM-Newton and Chandra are now needed to investigate the properties of the surrounding nebula.

  5. DISCOVERY OF X-RAY EMISSION FROM SUPERNOVA 1970G WITH CHANDRA: FILLING THE VOID BETWEEN SUPERNOVAE AND SUPERNOVA REMNANTS

    NASA Technical Reports Server (NTRS)

    Immler, Stefan; Kuntz, K. D.

    2005-01-01

    We report the discovery of X-ray emission from SN 1970G in M101, 35 yr after its outburst, using deep X-ray imaging with the Chundra X-Ray Observatory. The Chandra ACIS spectrum shows that the emission is soft (52 keV) and characteristic of the reverse-shock region. The X-ray luminosity, Lo,,, = (1.1 3 0.2) x lo3# ergs s-1, is likely caused by the interaction of the supernova shock with dense circumstellar matter. If the material was deposited by the stellar wind from the progenitor, a mass-loss rate of M = (2.6 ? 0.4) x M, yr-I (v,/lO km s-I) is inferred. Utilizing the high-resolution Chandra ACIS data of SN 1970G and its environment, we reconstruct the X-ray lightcurve from previous ROSAT HRI, PSPC, and XMM-Newton EPIC observations, and find a best-fit linear rate of decline of L cc t-# with index s = 2.7 t 0.9 over a period of -20-35 yr after the outburst. As the oldest supernova detected in X-rays, SN 1970G allows, for the first time, direct observation of the transition from a supenova to its supernova remnant phase.

  6. GBM Observations of Be X-Ray Binary Outbursts

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.; Finger, M. H.; Jenke, P. A.

    2014-01-01

    Since 2008 we have been monitoring accreting pulsars using the Gamma ray Burst Monitor (GBM) on Fermi. This monitoring program includes daily blind full sky searches for previously unknown or previously quiescent pulsars and source specific analysis to track the frequency evolution of all detected pulsars. To date we have detected outbursts from 23 transient accreting pulsars, including 21 confirmed or likely Be/X-ray binaries. I will describe our techniques and highlight results for selected pulsars.

  7. A high sensitivity search for X-rays from supernova remnants in Aquila

    NASA Technical Reports Server (NTRS)

    Schwartz, D. A.; Bleach, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

    1972-01-01

    A high sensitivity scan of the galactic plane was performed to search for 2-20 keV X-rays from supernova remnants. The spectra of five X-ray sources detected between 44 deg and 31 deg longitude, of which only two might be associated with suggested supernova remnants, are reported on. Upper limits are presented for the 19 possible supernova remnants scanned in this survey.

  8. A high-sensitivity search for X-rays from supernova remnants in Aquila.

    NASA Technical Reports Server (NTRS)

    Schwartz, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Bleach, R. D.

    1972-01-01

    A high-sensitivity scan of the galactic plane from 70 to 30 deg was performed to search for 2-20-keV X rays from supernova remnants. The spectra of five X-ray sources detected between 44 and 31 deg longitude are presented, of which only two might be associated with suggested supernova remnants. Upper limits are given for the 19 possible supernova remnants scanned.

  9. AN X-RAY AND OPTICAL LIGHT CURVE MODEL OF THE ECLIPSING SYMBIOTIC BINARY SMC3

    SciTech Connect

    Kato, Mariko; Hachisu, Izumi; Mikolajewska, Joanna

    2013-01-20

    Some binary evolution scenarios for Type Ia supernovae (SNe Ia) include long-period binaries that evolve to symbiotic supersoft X-ray sources in their late stage of evolution. However, symbiotic stars with steady hydrogen burning on the white dwarf's (WD) surface are very rare, and the X-ray characteristics are not well known. SMC3 is one such rare example and a key object for understanding the evolution of symbiotic stars to SNe Ia. SMC3 is an eclipsing symbiotic binary, consisting of a massive WD and red giant (RG), with an orbital period of 4.5 years in the Small Magellanic Cloud. The long-term V light curve variations are reproduced as orbital variations in the irradiated RG, whose atmosphere fills its Roche lobe, thus supporting the idea that the RG supplies matter to the WD at rates high enough to maintain steady hydrogen burning on the WD. We also present an eclipse model in which an X-ray-emitting region around the WD is almost totally occulted by the RG swelling over the Roche lobe on the trailing side, although it is always partly obscured by a long spiral tail of neutral hydrogen surrounding the binary in the orbital plane.

  10. On the formation of galactic black hole low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Jia, Kun; Li, Xiang-Dong

    2016-03-01

    Currently, there are 24 black hole (BH) X-ray binary systems that have been dynamically confirmed in the Galaxy. Most of them are low-mass X-ray binaries (LMXBs) comprised of a stellar-mass BH and a low-mass donor star. Although the formation of these systems has been extensively investigated, some crucial issues remain unresolved. The most noticeable one is that, the low-mass companion has difficulties in ejecting the tightly bound envelope of the massive primary during the spiral-in process. While initially intermediate-mass binaries are more likely to survive the common envelope (CE) evolution, the resultant BH LMXBs mismatch the observations. In this paper, we use both stellar evolution and binary population synthesis to study the evolutionary history of BH LMXBs. We test various assumptions and prescriptions for the supernova mechanisms that produce BHs, the binding energy parameter, the CE efficiency and the initial mass distributions of the companion stars. We obtain the birthrate and the distributions of the donor mass, effective temperature and orbital period for the BH LMXBs in each case. By comparing the calculated results with the observations, we put useful constraints on the aforementioned parameters. In particular, we show that it is possible to form BH LMXBs with the standard CE scenario if most BHs are born through failed supernovae.

  11. Formation and Destruction of Jets in X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Kylafix, N. D.; Contopoulos, I.; Kazanas, D.; Christodoulou, D. M.

    2011-01-01

    Context. Neutron-star and black-hole X-ray binaries (XRBs) exhibit radio jets, whose properties depend on the X-ray spectral state e.nd history of the source. In particular, black-hole XRBs emit compact, 8teady radio jets when they are in the so-called hard state. These jets become eruptive as the sources move toward the soft state, disappear in the soft state, and then re-appear when the sources return to the hard state. The jets from neutron-star X-ray binaries are typically weaker radio emitters than the black-hole ones at the same X-ray luminosity and in some cases radio emission is detected in the soft state. Aims. Significant phenomenology has been developed to describe the spectral states of neutron-star and black-hole XRBs, and there is general agreement about the type of the accretion disk around the compact object in the various spectral states. We investigate whether the phenomenology describing the X-ray emission on one hand and the jet appearance and disappearance on the other can be put together in a consistent physical picture. Methods. We consider the so-called Poynting-Robertson cosmic battery (PRCB), which has been shown to explain in a natural way the formation of magnetic fields in the disks of AGNs and the ejection of jets. We investigate whether the PRCB can also explain the [ormation, destruction, and variability or jets in XRBs. Results. We find excellent agreement between the conditions under which the PRCB is efficient (i.e., the type of the accretion disk) and the emission or destruction of the r.adio jet. Conclusions. The disk-jet connection in XRBs can be explained in a natural way using the PRCB.

  12. Effects of variability of X-ray binaries on the X-ray luminosity functions of Milky Way

    NASA Astrophysics Data System (ADS)

    Islam, Nazma; Paul, Biswajit

    2016-08-01

    The X-ray luminosity functions of galaxies have become a useful tool for population studies of X-ray binaries in them. The availability of long term light-curves of X-ray binaries with the All Sky X-ray Monitors opens up the possibility of constructing X-ray luminosity functions, by also including the intensity variation effects of the galactic X-ray binaries. We have constructed multiple realizations of the X-ray luminosity functions (XLFs) of Milky Way, using the long term light-curves of sources obtained in the 2-10 keV energy band with the RXTE-ASM. The observed spread seen in the value of slope of both HMXB and LMXB XLFs are due to inclusion of variable luminosities of X-ray binaries in construction of these XLFs as well as finite sample effects. XLFs constructed for galactic HMXBs in the luminosity range 1036-1039 erg/sec is described by a power-law model with a mean power-law index of -0.48 and a spread due to variability of HMXBs as 0.19. XLFs constructed for galactic LMXBs in the luminosity range 1036-1039 erg/sec has a shape of cut-off power-law with mean power-law index of -0.31 and a spread due to variability of LMXBs as 0.07.

  13. X-RAY BINARY EVOLUTION ACROSS COSMIC TIME

    SciTech Connect

    Fragos, T.; Zezas, A.; Lehmer, B.; Tzanavaris, P.; Tremmel, M.; Basu-Zych, A.; Hornschemeier, A.; Jenkins, L.; Ptak, A.; Belczynski, K.; Kalogera, V.

    2013-02-10

    High-redshift galaxies permit the study of the formation and evolution of X-ray binary (XRB) populations on cosmological timescales, probing a wide range of metallicities and star formation rates (SFRs). In this paper, we present results from a large-scale population synthesis study that models the XRB populations from the first galaxies of the universe until today. We use as input to our modeling the Millennium II cosmological simulation and the updated semi-analytic galaxy catalog by Guo et al. to self-consistently account for the star formation history and metallicity evolution of the universe. Our modeling, which is constrained by the observed X-ray properties of local galaxies, gives predictions about the global scaling of emission from XRB populations with properties such as SFR and stellar mass, and the evolution of these relations with redshift. Our simulations show that the X-ray luminosity density (X-ray luminosity per unit volume) from XRBs in our universe today is dominated by low-mass XRBs, and it is only at z {approx}> 2.5 that high-mass XRBs become dominant. We also find that there is a delay of {approx}1.1 Gyr between the peak of X-ray emissivity from low-mass XRBs (at z {approx} 2.1) and the peak of SFR density (at z {approx} 3.1). The peak of the X-ray luminosity from high-mass XRBs (at z {approx} 3.9) happens {approx}0.8 Gyr before the peak of the SFR density, which is due to the metallicity evolution of the universe.

  14. Supergiant X-Ray Binaries Observed by Suzaku

    NASA Technical Reports Server (NTRS)

    Bodaghee, A.; Tomsick, J. A.; Rodriquez, J.; Chaty, S.; Pottschmidt, K.; Walter, R.; Romano, P.

    2011-01-01

    Suzaku observations are presented for the high-mass X-ray binaries IGR 116207-5129 and IGR 117391-3021. For IGR 116207-5129, we provide the first X-ray broadband (0.5-60 keV) spectrum from which we confirm a large intrinsic column density (N(sub H) = 1.6 x 10(exp 23)/sq cm), and we constrain the cutoff energy for the first time (E(sub cut) = 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> 50 degrees. For IGRJ17391-3021, we witnessed a transition from quiescence to a low-activity phase punctuated by weak flares whose peak luminosities in the 0.5-10keV band are only a factor of 5 times that of the pre-flare emission. These micro flares are accompanied by an increase in NH which suggests the accretion of obscuring clumps of wind. We now recognize that these low-activity epochs constitute the most common emission phase for this system, and perhaps in other supergiant fast X-ray transients (SFXTs) as well. We close with an overview of our upcoming program in which Suzaku will provide the first ever observation of an SFXT (IGRJ16479-4514) during a binary orbit enabling us to probe the accretion wind at every phase.

  15. An optical supernova associated with the X-ray flash XRF 060218.

    PubMed

    Pian, E; Mazzali, P A; Masetti, N; Ferrero, P; Klose, S; Palazzi, E; Ramirez-Ruiz, E; Woosley, S E; Kouveliotou, C; Deng, J; Filippenko, A V; Foley, R J; Fynbo, J P U; Kann, D A; Li, W; Hjorth, J; Nomoto, K; Patat, F; Sauer, D N; Sollerman, J; Vreeswijk, P M; Guenther, E W; Levan, A; O'Brien, P; Tanvir, N R; Wijers, R A M J; Dumas, C; Hainaut, O; Wong, D S; Baade, D; Wang, L; Amati, L; Cappellaro, E; Castro-Tirado, A J; Ellison, S; Frontera, F; Fruchter, A S; Greiner, J; Kawabata, K; Ledoux, C; Maeda, K; Møller, P; Nicastro, L; Rol, E; Starling, R

    2006-08-31

    Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes--analogues of GRBs, but with lower luminosities and fewer gamma-rays--can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae. PMID:16943831

  16. The slow X-ray pulsar SXP 1062 and associated supernova remnant in the Wing of the Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Oskinova, L. M.; Guerrero, M. A.; Hénault-Brunet, V.; Sun, W.; Chu, Y.-H.; Evans, C.; Gallagher, J. S.; Gruendl, R. A.; Reyes-Iturbide, J.

    2013-03-01

    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.

  17. Accretion and Outflows in X-ray Binaries: What's Really Going on During X-ray Quiescence

    NASA Astrophysics Data System (ADS)

    MacDonald, Rachel K. D.; Bailyn, Charles D.; Buxton, Michelle

    2015-01-01

    X-ray binaries, consisting of a star and a stellar-mass black hole, are wonderful laboratories for studying accretion and outflows. They evolve on timescales quite accessible to us, unlike their supermassive cousins, and allow the possibility of gaining a deeper understanding of these two common astrophysical processes. Different wavelength regimes reveal different aspects of the systems: radio emission is largely generated by outflows and jets, X-ray emission by inner accretion flows, and optical/infrared (OIR) emission by the outer disk and companion star. The search for relationships between these different wavelengths is thus an area of active research, aiming to reveal deeper connections between accretion and outflows.Initial evidence for a strong, tight correlation between radio and X-ray emission has weakened as further observations and newly-discovered sources have been obtained. This has led to discussions of multiple tracks or clusters, or the possibility that no overall relation exists for the currently-known population of X-ray binaries. Our ability to distinguish among these options is hampered by a relative lack of observations at lower luminosities, and especially of truly X-ray quiescent (non-outbursting) systems. Although X-ray binaries spend the bulk of their existence in quiescence, few quiescent sources have been observed and multiple observations of individual sources are largely nonexistent. Here we discuss new observations of the lowest-luminosity quiescent X-ray binary, A0620-00, and the place this object occupies in investigations of the radio/X-ray plane. For the first time, we also incorporate simultaneous OIR data with the radio and X-ray data.In December 2013 we took simultaneous observations of A0620-00 in the X-ray (Chandra), the radio (EVLA), and the OIR (SMARTS 1.3m). These X-ray and radio data allowed us to investigate similarities among quiescent X-ray binaries, and changes over time for this individual object, in the radio/X-ray

  18. On the torque reversal occurred in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Gong, Biping

    The effect of torque reversal has been observed in a number of X-ray binaries, such as 4U1627-67, Her X-1, Cen X-3, GX 1+4, OAO 1657-415, and Vela X-1. Here we suggest that it originates in a simply mechanism, residual Doppler shift. In a binary system with periodic signals sending to an observer, the drift of the signal frequency actually changes with the varying orbital velocity, projected to line of sight at different phases of orbit. And it has been taken for granted that the net red-shift and blue-shift of an full orbit circle be cancelled out, so that the effect of Doppler shift to the signal in binary motion cannot be accumulated over the orbital period. However, taking the propagation time at each velocity state into account, the symmetry of the velocity distribution over the orbital phase is broken. Consequently, the net Doppler shift left in an orbit is non-zero. It is this Newtonian second Doppler effect that responsible for the torque reversal occurred in X-ray binaries.

  19. Estimates of black hole natal kick velocities from observations of low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Mandel, Ilya

    2016-02-01

    The birth kicks of black holes, arising from asymmetric mass ejection or neutrino emission during core-collapse supernovae, are of great interest for both observationally constraining supernova models and population-synthesis studies of binary evolution. Recently, several efforts were undertaken to estimate black hole birth kicks from observations of black hole low-mass X-ray binaries. We follow up on this work, specifically focusing on the highest estimated black hole kick velocities. We find that existing observations do not require black hole birth kicks in excess of approximately 80 km s-1, although higher kicks are not ruled out.

  20. Star formation history and X-ray binary populations: the case of the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Antoniou, V.; Zezas, A.

    2016-06-01

    In this work we investigate the link between high-mass X-ray binaries (HMXBs) and star formation in the Large Magellanic Cloud (LMC), our nearest star-forming galaxy. Using optical photometric data, we identify the most likely counterpart of 44 X-ray sources. Among the 40 HMXBs classified in this work, we find 33 Be/X-ray binaries (Be-XRBs), and 4 supergiant XRBs. Using this census and the published spatially resolved star formation history map of the LMC, we find that the HMXBs (and as expected the X-ray pulsars) are present in regions with star formation bursts ∼6-25 Myr ago, in contrast to the Small Magellanic Cloud (SMC), for which this population peaks at later ages (∼25-60 Myr ago). We also estimate the HMXB production rate to be equal to one system per ∼43.5× 10-3 M⊙ yr-1 or one system per ∼143M⊙ of stars formed during the associated star formation episode. Therefore, the formation efficiency of HMXBs in the LMC is ∼17 times lower than that in the SMC. We attribute this difference primarily in the different ages and metallicity of the HMXB populations in the two galaxies. We also set limits on the kicks imparted on the neutron star during the supernova explosion. We find that the time elapsed since the supernova kick is ∼3 times shorter in the LMC than the SMC. This in combination with the average offsets of the HMXBs from their nearest star clusters results in ∼4 times faster transverse velocities for HMXBs in the LMC than in the SMC.

  1. Different X-ray spectral evolution for black hole X-ray binaries in dual tracks of radio-X-ray correlation

    SciTech Connect

    Cao, Xiao-Feng; Wu, Qingwen; Dong, Ai-Jun

    2014-06-10

    Recently, an 'outlier' track of radio-X-ray correlation was found, which is much steeper than the former universal correlation, where dual tracks were speculated to be triggered by different accretion processes. In this work, we test this issue by exploring hard X-ray spectral evolution in four black-hole X-ray binaries with multiple, quasi-simultaneous radio and X-ray observations. First, we find that hard X-ray photon indices, Γ, are negatively and positively correlated with X-ray fluxes when the X-ray flux, F{sub 3-9} {sub keV}, is below and above a critical flux, F{sub X,} {sub crit}, which are consistent with predictions of the advection-dominated accretion flow and the disk-corona model, respectively. Second, and most importantly, we find that the radio-X-ray correlations are also clearly different when the X-ray fluxes are higher and lower than the critical flux as defined by X-ray spectral evolution. The data points with F{sub 3-9} {sub keV} ≳ F{sub X,} {sub crit} have a steeper radio-X-ray correlation (F{sub X}∝F{sub R}{sup b} and b ∼ 1.1-1.4), which roughly forms the ''outlier'' track. However, the data points with anti-correlation of Γ – F{sub 3-9} {sub keV} either stay in the universal track with b ∼ 0.61 or stay in the transition track (from the universal to 'outlier' tracks or vice versa). Therefore, our results support that the universal and ''outlier'' tracks of radio-X-ray correlations are regulated by radiatively inefficient and radiatively efficient accretion model, respectively.

  2. The origin of the hard X-ray tail in neutron-star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Reig, P.; Kylafis, N.

    2016-06-01

    Context. Neutron star X-ray binaries emit a compact, optically thick, relativistic radio jet during low-luminosity, usually hard states, as Galactic black-hole X-ray binaries do. When radio emission is bright, a hard power-law tail without evidence for an exponential cutoff is observed in most systems. Aims: We have developed a jet model that explains many spectral and timing properties of black-hole binaries in the states where a jet is present. Our goal is to investigate whether our jet model can reproduce the hard tail, with the correct range of photon index and the absence of a high-energy cutoff, in neutron-star X-ray binaries. Methods: We performed Monte Carlo simulations of the Compton upscattering of soft, accretion-disk or boundary layer photons in the jet and computed the emergent energy spectra, as well as the time lag of hard photons with respect to softer ones as a function of Fourier frequency. We fit the energy spectra with a power law modified by an exponential cutoff at high energy. Results: We demonstrate that our jet model naturally explains the observed power-law distribution with photon index in the range 1.8-3. With an appropriate choice of the parameters, the cutoff expected from Comptonization is shifted to energies above ~300 keV, producing a pure power law without any evidence for a rollover, in agreement with the observations. Conclusions: Our results reinforce the idea that the link between the outflow (jet) and inflow (disk) in X-ray binaries does not depend on the nature of the compact object, but on the process of accretion. Furthermore, we address the differences between jets in black-hole and neutron-star X-ray binaries and predict that the break frequency in the spectral energy distribution of neutron-star X-ray binaries, as a class, will be lower than that of black-hole binaries.

  3. SPECTRAL PROPERTIES OF X-RAY BINARIES IN CENTAURUS A

    SciTech Connect

    Burke, Mark J.; Raychaudhury, Somak; Kraft, Ralph P.; Forman, William R.; Jones, Christine; Murray, Stephen S.; Birkinshaw, Mark; Evans, Daniel A.; Jordan, Andres; Maccarone, Thomas J.; Croston, Judith H.; Brassington, Nicola J.; Hardcastle, Martin J.; Goodger, Joanna L.; Kainulainen, Jouni; Woodley, Kristin A.; Sivakoff, Gregory R.; Gilfanov, Marat; Sarazin, Craig L.; Voss, Rasmus [Department of Astrophysics and others

    2013-04-01

    We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N{sub H}, and present the spectral parameters of sources with L{sub x} {approx}> 2 Multiplication-Sign 10{sup 37} erg s{sup -1}. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent 'gap' in the mass distribution of compact objects between {approx}2-5 M{sub Sun }. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority ({approx}70%-80%) of potential Roche lobe filling donors in the Cen A halo are {approx}> 12 Gyr old, while BH LMXBs require donors {approx}> 1 M{sub Sun} to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at L{sub x} {>=} 5 Multiplication-Sign 10{sup 38} erg s{sup -1} for the XB population of early-type galaxies; for older stellar populations, there are fewer stars {approx}> 1 M{sub Sun }, which are required to form the more luminous sources.

  4. STATE TRANSITIONS IN LOW-MASS X-RAY BINARIES

    SciTech Connect

    Bradley, Charles K.; Frank, Juhan

    2009-10-10

    We investigate the model of disk/coronal accretion into a black hole. We show that the inner regions of an accretion disk in X-ray binaries can transform from a cool standard disk to an advection-dominated flow through the known properties of Coulomb interaction in a two-temperature plasma, viscous heating, radiative processes, and thermal conduction. A hot, diffuse corona covering the disk is powered by accretion, but it exchanges mass with the underlying cold disk. If the accretion rate in the system is low enough, we show that the corona evaporates the disk away, leaving an advective flow to continue toward the hole. In the soft/hard transition commonly seen in X-ray binaries, we show that this advective flow can recondense back onto the underlying disk if the change in the system's accretion rate is slow enough due to thermal conduction. Unabsorbed spectra are produced to test against observations as well as prediction of the location of truncation radii of the accretion disk.

  5. A Study on the Evolution of Compact Star Binaries and Stellar X-ray Sources

    NASA Astrophysics Data System (ADS)

    Xu, X. J.

    2014-03-01

    X-ray serves as one of the most important domains of discovery in astronomy. It could be used to study the properties as well as the formation and evolution of X-ray emitting objects. X-ray can also be used to constrain the formation and evolution history of galaxies in the universe. In this thesis, we discuss the properties of the X-ray point sources, especially those with white dwarfs as accretors. We focus on the evolution of these binaries and their progenitors, as well as the relation between these objects and their host environments with the numerical and observational methods. We further put constraints on the final product and the possible connection to the type Ia supernovae. Our main results are as follows: (1) We study the case in which the thermally unstable accretion disks occur in binaries, and apply to the evolution of GRO J1744-28 and type Ia supernovae. Our result shows that GRO J1744-28 could have evolved from a binary composed by a normal star and an ONeMg white dwarf and with the white dwarf as the accretor. During its evolution, the white dwarf experienced accretion from the X-ray irradiated unstable accretion disk, then accumulated mass by burning the accreted matter on its surface before it collapsed to a neutron star. The new formed neutron star then accreted from the companion again, and evolved to its present properties. We also apply the unstable disks to the binaries with C/O white dwarfs as accretors, and calculate the region of the initial companion masses and orbital periods which could lead to successful type Ia supernovae. The results suggest that the companion star of the progenitor system could have the initial mass as low as ≲ 1.5 M_{⊙}. (2) We study the λ parameter in the common envelope evolution. Our results show that the λ parameter varies for the stars with different initial masses. For the same star, λ also varies in different evolutional stages. At the end of their evolution, the stars with the approximate initial

  6. On binary-driven hypernovae and their nested late X-ray emission

    NASA Astrophysics Data System (ADS)

    Ruffini, R.; Muccino, M.; Bianco, C. L.; Enderli, M.; Izzo, L.; Kovacevic, M.; Penacchioni, A. V.; Pisani, G. B.; Rueda, J. A.; Wang, Y.

    2014-05-01

    Context. The induced gravitational collapse (IGC) paradigm addresses the very energetic (1052-1054 erg) long gamma-ray bursts (GRBs) associated to supernovae (SNe). Unlike the traditional "collapsar" model, an evolved FeCO core with a companion neutron star (NS) in a tight binary system is considered as the progenitor. This special class of sources, here named "binary-driven hypernovae" (BdHNe), presents a composite sequence composed of four different episodes with precise spectral and luminosity features. Aims: We first compare and contrast the steep decay, the plateau, and the power-law decay of the X-ray luminosities of three selected BdHNe (GRB 060729, GRB 061121, and GRB 130427A). Second, to explain the different sizes and Lorentz factors of the emitting regions of the four episodes, for definiteness, we use the most complete set of data of GRB 090618. Finally, we show the possible role of r-process, which originates in the binary system of the progenitor. Methods: We compare and contrast the late X-ray luminosity of the above three BdHNe. We examine correlations between the time at the starting point of the constant late power-law decay t*a, the average prompt luminosity ⟨ Liso ⟩, and the luminosity at the end of the plateau La. We analyze a thermal emission (~ 0.97-0.29 keV), observed during the X-ray steep decay phase of GRB 090618. Results: The late X-ray luminosities of the three BdHNe, in the rest-frame energy band 0.3-10 keV, show a precisely constrained "nested" structure. In a space-time diagram, we illustrate the different sizes and Lorentz factors of the emitting regions of the three episodes. For GRB 090618, we infer an initial dimension of the thermal emitter of ~ 7 × 1012 cm, expanding at Γ ≈ 2. We find tighter correlations than the Dainotti-Willingale ones. Conclusions: We confirm a constant slope power-law behavior for the late X-ray luminosity in the source rest frame, which may lead to a new distance indicator for BdHNe. These results

  7. Linking jet emission and X-ray properties in the peculiar neutron star X-ray binary Circinus X-1

    NASA Astrophysics Data System (ADS)

    Soleri, Paolo; Tudose, Valeriu; Fender, Rob; van der Klis, Michiel; Jonker, Peter G.

    2009-10-01

    We present the results of simultaneous X-ray and radio observations of the peculiar Z-type neutron star X-ray binary Cir X-1, observed with the Rossi X-ray Timing Explorer satellite and the Australia Telescope Compact Array in 2000 October and 2002 December. We identify typical Z-source behaviour in the power density spectra as well as characteristic Z patterns drawn in an X-ray hardness-intensity diagram. Power spectra typical of bright atoll sources have also been identified at orbital phases after the periastron passage, while orbital phases before the periastron passage are characterized by power spectra that are typical neither of Z nor of atoll sources. We investigate the coupling between the X-ray and the radio properties, focusing on three orbital phases when an enhancement of the radio flux density has been detected, to test the link between the inflow (X-ray) and the outflow (radio jet) to/from the compact object. In two out of three cases, we associate the presence of the radio jet to a spectral transition in the X-rays, although the transition does not precede the radio flare, as detected in other Z sources. An analogous behaviour has recently been found in the black hole candidate GX 339-4. In the third case, the radio light curve shows a similar shape to the X-ray light curve. We discuss our results in the context of jet models, considering also black hole candidates.

  8. X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission

    NASA Technical Reports Server (NTRS)

    Immler, S.; Brown, P. J.; Milne, P.; Dessart, L.; Mazzali, P. A.; Landsman, W.; Gehrels, N.; Petre, R.; Burrows, D. N.; Nousek, J. A.; Chevalier, R. A.; Williams, C. L.; Koss, M.; Stockdale, C. J.; Kelley, M. T.; Weiler, K. W.; Holland, S. T.; Pian, E.; Roming, P. W. A.; Pooley, D.; Nomoto, K.; Greiner, J.; Campana, S.; Soderberg, A. M.

    2007-01-01

    We present results on the X-ray and optical/UV emission from the Type IIP supernova (SN) 2006bp and the interaction of the SW shock with its environment, obtained with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on-board the Swift observatory. SN 2006bp is detected in X-rays at a 4.5 sigmalevel of significance in the merged XRT data from days 1 to 12 after the explosion. If the (0.2-10 keV band) X-ray luminosity of L(sub 0.2-10) = (1.8 plus or minus 0.4) x l0(exp 39 ergs s(exp -1) is caused by interaction of the SN shock with circumstellar material (CSM), deposited by a stellar wind from the progenitor's companion star, a mass-loss rate of M is approximately 2x10(exp -6) solar mass yr(exp -1) (v(sub w)/10 km s(exp -l) is inferred. The mass-loss rate is one of the lowest ever recorded for a core-collapse SN and consistent with the non-detection in the radio with the VLA on days 2, 9, and 11 after the explosion. The Swift data further show a fading of the X-ray emission starting around day 12 after the explosion. In combination with a follow-up XMM-Newton observation obtained on day 21 after the explosion, an X-ray rate of decline Lx, varies as t(exp -n) with index n = 1.2 plus or minus 0.6 is inferred. Since no other SN has been detected in X-rays prior to the optical peak and since Type IIP SNe have an extended 'plateau' phase in the optical, we discuss the scenario that the X-rays might be due to inverse Compton scattering of photospheric optical photons off relativistic electrons produced in circumstellar shocks. However, due to the high required value of the Lorentz factor (approximately 10-100), inconsistent with the ejecta velocity inferred from optical line widths, we conclude that Inverse Compton scattering is an unlikely explanation for the observed X-ray emission. The fast evolution of the optical/ultraviolet (1900-5500A) spectral energy distribution and the spectral changes observed with Swift reveal the onset of metal line-blanketing and

  9. A disc corona-jet model for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin; Liu, B. F.

    2015-04-01

    The observed tight radio/X-ray correlation in the low spectral state of some black hole X-ray binaries implies the strong coupling of the accretion and jet. The correlation of L_R ∝ L_X^{˜ 0.5-0.7} was well explained by the coupling of a radiatively inefficient accretion flow and a jet. Recently, however, a growing number of sources show more complicated radio/X-ray correlations, e.g. L_R ∝ L_X^{˜ 1.4} for LX/LEdd ≳ 10-3, which is suggested to be explained by the coupling of a radiatively efficient accretion flow and a jet. In this work, we interpret the deviation from the initial radio/X-ray correlation for LX/LEdd ≳ 10-3 with a detailed disc corona-jet model. In this model, the disc and corona are radiatively and dynamically coupled. Assuming a fraction of the matter in the accretion flow, η ≡ dot{M}_jet/dot{M}, is ejected to form the jet, we can calculate the emergent spectrum of the disc corona-jet system. We calculate LR and LX at different dot{M}, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for LX/LEdd > 10-3. It is found that always the X-ray emission is dominated by the disc corona and the radio emission is dominated by the jet. We noted that the value of η for the deviated radio/X-ray correlation for LX/LEdd > 10-3 is systematically less than that of the case for LX/LEdd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high-luminosity phase in black hole X-ray binaries.

  10. Displacement of X-ray binaries: constraints on the natal kicks

    NASA Astrophysics Data System (ADS)

    Zuo, Zhao-Yu

    2015-01-01

    Context. This work uses the measured luminosity vs. displacement (LX vs. R) distribution of high-mass X-ray binaries (HMXBs) to constrain the dispersion of kick velocity σkick, which is an important parameter affecting the system velocity of a binary, and hence its spatial offset from the point of origin. Aims: The aim is to constrain the natal kicks and discriminate between models by comparing the observed LX vs. R distributions with the theoretical simulations. Methods: Using an up-to-date evolutionary population synthesis technique, the spatial offsets of HMXBs are modeled for a range of theoretical models describing the natal kicks, including different choices of the dispersion of kick velocity σkick, as well as different theoretical treatments for black hole (BH) natal kicks. Results: The study shows that the value of σkick for neutron stars (NSs) is constrained to be greater than ~100 km s-1, while σkick on the order of several tens of km s-1 may be excluded, though a low or absent natal kick for electron capture supernovae NSs is permitted. In particular, BH natal kicks are found not indispensable to account for the LX vs. R distributions. It is more interesting that full BH natal kicks (i.e., similar to those that NSs may receive) are likely to be ruled out in this study, which is in contrast with the recent finding to explain the observed distribution of low-mass X-ray binaries hosting BHs.

  11. Orbital period changes in massive X-ray binaries

    NASA Technical Reports Server (NTRS)

    Kelley, Richard L.

    1986-01-01

    Data from long-term pulse-timing observations of Cen X-3 are compiled and analyzed to determine the evolution of the orbital period, and the implications of the results for other massive X-ray binaries are discussed. Third-body effects, tidal effects, and mass-loss/transfer effects are considered as possible causes for the orbital-period decay observed in Cen X-3, and it is concluded that strong tidal coupling between the companion star and the orbital causes the period decay via orbital instability and/or mass loss. Applying these results to the Roche-lobe-overflow models of Savonije (1983), the evolutionary expansion rate of the Cen X-3 companion and the Roche-lobe shrinking rate are estimated as about 2 x 10 to the -7th/yr and about 1 x 10 to the -6th/yr, respectively, implying an X-ray lifetime of about 5000 yr. Estimates of the companion mass-change rate and period decay for Cen X-3 and four other objects are presented in a table.

  12. A Unified Model of Low Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Balucinska-Church, M.; Church, M.

    2014-07-01

    We present a unified physical model of Low Mass X-ray Binaries explaining the basic Atoll and Z-track types of source. In all LMXB with luminosity above 1-2.10^{37} erg/s, we have a new fundamental result that the temperature of the Comptonizing ADC corona equals that of the neutron star, i.e. there is thermal equilibrium. This equilibrium explains the properties of the basic Banana State of Atoll sources. Below this luminosity, equilibrium breaks down, T_ADC rising towards 100 keV by an unknown heating mechanism, explaining the Island State. Above 5.10^{37} erg/s flaring begins in the GX-Atolls which we show is unstable nuclear burning. Above 1.10^{38} erg/s, LMXB are seen as Z-track sources. Flaring in these and the GX-Atolls occurs when the mass accretion rate to the neutron star falls to the critical value for unstable nuclear burning on the star. Below 2.10^{37} erg/s, a different unstable burning: X-ray bursting, takes over. We show that the Normal Branch of the Z-track consists simply of increasing mass accretion rate, as is the Banana State in Atolls. In the Horizontal Branch, a measured, strongly increasing radiation pressure of the neutron star disrupts the inner disk launching the relativistic jets seen on this branch.

  13. Insights into the High-Mass X-ray Binary Population of the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Antoniou, V.; Zezas, A.; Hatzidimitriou, D.; Kalogera, V.

    2013-09-01

    In contrast to the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), our nearest starforming galaxy with metallicity between the Galaxy and the SMC, has received little attention in X-rays so far. With the aim to compare the accreting X-ray binary (XRB) populations in two of our nearest star-forming galaxies, we recently compiled the most complete census of high-mass X-ray binaries (HMXBs) in the LMC. We found 43 members of which 13 are XRB pulsars, while we also identified their most likely optical counterpart (previously, half of these sources lacked an identification). Using this census, we investigated the link between the young accreting XRBs and their parent stellar populations. It was known that HMXBs can be used as star-formation (SF) rate indicators, but these first studies have been focused only on bright systems (Galaxy: >1038 erg s-1, Magellanic Clouds: >1036 erg s-1) and SF values for the whole galaxy. By including Magellanic Cloud sources with X-ray luminosities at least two order of magnitudes fainter than the above limits and by utilizing the detailed, spatially resolved, SF history maps of these galaxies, we were able to provide observational constraints on ill-understood parameters related to their formation and evolution (such as the kick velocities imparted into the neutron star during the supernova explosion) and to derive their formation efficiency. This work was mainly supported by the National Aeronautics and Space Administration under Grant No. NNX10AH47G issued through the Astrophysics Data Analysis Program.

  14. Two component X-ray emission from RS CVn binaries

    NASA Technical Reports Server (NTRS)

    Swank, J. H.; White, N. E.; Holt, S. S.; Becker, R. H.

    1980-01-01

    A summary of results from the solid state spectrometer on the Einstein Observatory for 7 RS CVn binaries is presented. The spectra of all require two emission components, evidenced by line emission characteristic of plasma at 4 to 8 x 10 to the 6th power and bremsstrahlung characteristic of 20 to 100 x 10 to the 6th power K. The data are interpreted in terms of magnetic coronal loops similar to those seen on the Sun, although with different characteristic parameters. The emission regions could be defined by separate magnetic structures. For pressure less than approximately 10 dynes/sq cm the low temperature plasma would be confined within the stellar radii, while the high temperature plasma would, for the synchronous close binaries, fill the binary orbits. However, for loop pressures exceeding 100 dynes/sq cm, the high temperature components would also be confined to within the stellar radii, in loops covering only small fractions of the stellar surfaces. While the radio properties and the occurrence of X-ray flares suggest the larger emission regions, the observations of time variations leave the ambiguity unresolved.

  15. WISE Detection of Low-Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Wang, Zhongxiang

    2014-08-01

    I will report on the results from our search for the Wide-field Infrared Survey Explorer detection of the Galactic low-mass X-ray binaries. Among 187 catalogued binaries, we find 13 counterparts and two candidate counterparts. For the 13 counterparts, two (4 0614+091 and G 339-4) have already been confirmed by previous studies to have a jet and one (GR 1915+105) to have a candidate circumbinary disk, from which the detected infrared emission arose. Having collected the broad-band optical and near-infrared data in literature and constructed flux density spectra for the other 10 binaries, we identify that three (A0620-00, XTE J1118+480, and GX 1+4) are candidate circumbinary disk systems, four (Cen X-4, 4U 1700+24, 3A 1954+319, and Cyg X-2) had thermal emission from their companion stars, and three (Sco X-1, Her X-1, and Swift J1753.5-0127) are peculiar systems with the origin of their infrared emission rather uncertain. Discussion of the results and WISE counterparts' brightness distribution will be provided, which suggests that more than half of the LMXBs would have a jet, a circumbinary disk, or the both.

  16. Testing accretion disk instabilities in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Bagińska, Patrycja; Różańska, Agata; Janiuk, Agnieszka; Czerny, Bożena

    2014-12-01

    We study disk instabilities in black hole binaries in which X-ray novae outbursts were observed. Typically, one outburst occurs in each light curve, with total duration from 30 up to 400 days. The shape of an outburst can be very regular fast rise exponential decay (FRED) characteristic for ionisation instability mechanism that occurs in accretion disks, or irregular suggesting that, beside FRED, additional flickering occurs. We use the model which predicts time dependent evolution of ionisation instability in an accretion disk around black hole, assuming viscosity parameter to be proportional to the total pressure. We test it in detail for two objects: GX 339-4 and XTE J1818-245. The modelled light curves agree with the collected RXTE light curves, indicating that disk instability works in those objects.

  17. The donor star winds in High-Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Oskinova, Lida

    2014-10-01

    High-mass X-ray binaries (HMXBs) are essential astrophysical laboratories. These objects represent an advanced stage in the evolution of massive binary systems, after the initially more massive star has already collapsed in a supernova explosion, but its remnant, a neutron star or black hole, remains gravitationally bound. The stellar wind from the OB-type donor is partially accreted onto its compact companion powering its relatively high X-ray luminosity. Since HMXBs accrete from the stellar wind, parameters such as the donor's mass-loss rate, the velocity of the wind, and its clumpiness are of fundamental importance.This proposal takes advantage of the unique capabilities of HST/STIS for UV spectroscopy. We focus on the most populous in the Galaxy class of those HMXBs where the stellar wind of the OB donor is directly accreted onto a neutron star. Recently, a new sub-class of HMXBs - "supergiant fast X-ray transients" - was discovered. It has been proposed that these enigmatic objects can be explained by the specific properties of their donor-star winds. The only way to validate or disprove this hypothesis is by a studying the wind diagnostics lines in the UV spectra of donor stars. The observations proposed here will, for the first time, provide the UV spectra of this important new type of accreting binaries. Our state-of-the art non-LTE expanding stellar atmospheres and 3-D stellar wind simulations allow thorough exploitation of the STIS spectra. As a result we will obtain the wind parameters for a representative sample of six Galactic HMXBs, thus heightening our knowledge thereof considerably.

  18. X-ray emission from the supernova remnant G287.8-0.5

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Rothschild, R. E.; Serlemitsos, P. J.; Swank, J. H.

    1976-01-01

    The GSFC Cosmic X-ray spectroscopy experiment on OSO-8 observed a weak galactic X-ray source near theta 2 at 288 deg, b2 at -1 deg. The spectrum for this source between 2-20 keV is well represented by a thermal spectrum of kT = 7.34(+3.6), sub -2.6 keV with an intense iron emission line centered at 6.5 + or - .2 keV. The error box of the Uhuru source 4U1043-59, the only known X-ray source in our field of view, contains the radio supernova remnant G287.8-0.5. The possible association of the X-ray source with this supernova remnant is discussed.

  19. Be/X-Ray Pulsar Binary Science with LOFT

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    Accretion disks are ubiquitous in astronomical sources. Accretion powered pulsars are a good test bed for accretion disk physics, because unlike for other objects, the spin of the neutron star is directly observable allowing us to see the effects of angular momentum transfer onto the pulsar. The combination of a sensitive wide-field monitor and the large area detector on LOFT will enable new detailed studies of accretion powered pulsars which I will review. RXTE observations have shown an unusually high number of Be/X-ray pulsar binaries in the SMC. Unlike binaries in the Milky Way, these systems are all at the same distance, allowing detailed population studies using the sensitive LOFT WFM, potentially providing connections to star formation episodes. For Galactic accreting pulsar systems, LOFT will allow measurement of spectral variations within individual pulses, mapping the accretion column in detail for the first time. LOFT will also provide better constraints on magnetic fields in accreting pulsars, allowing measurements of cyclotron features, observations of transitions into the centrifugal inhibition regime, and monitoring of spin-up rate vs flux correlations. Coordinated multi-wavelength observations are crucial to extracting the best science from LOFT from these and numerous other objects.

  20. X-ray observations of the supernova remnant IC 443

    NASA Technical Reports Server (NTRS)

    Winkler, P. F., Jr.; Clark, G. W.

    1974-01-01

    Presented observation data from OSO-7 are shown to confirm the identification of IC 443 as an X-ray source, with a spectrum which is consistent with either thermal bremsstrahlung or a power law. These data lead to an age of 3400 years for IC 443, much younger than previous estimates.

  1. X-ray-binary spectra in the lamp post model

    NASA Astrophysics Data System (ADS)

    Vincent, F. H.; Różańska, A.; Zdziarski, A. A.; Madej, J.

    2016-05-01

    Context. The high-energy radiation from black-hole binaries may be due to the reprocessing of a lamp located on the black hole rotation axis and emitting X-rays. The observed spectrum is made of three major components: the direct spectrum traveling from the lamp directly to the observer; the thermal bump at the equilibrium temperature of the accretion disk heated by the lamp; and the reflected spectrum essentially made of the Compton hump and the iron-line complex. Aims: We aim to accurately compute the complete reprocessed spectrum (thermal bump + reflected) of black-hole binaries over the entire X-ray band. We also determine the strength of the direct component. Our choice of parameters is adapted to a source showing an important thermal component. We are particularly interested in investigating the possibility to use the iron-line complex as a probe to constrain the black hole spin. Methods: We computed in full general relativity the illumination of a thin accretion disk by a fixed X-ray lamp along the rotation axis. We used the ATM21 radiative transfer code to compute the local, energy-dependent spectrum emitted along the disk as a function of radius, emission angle and black hole spin. We then ray traced this local spectrum to determine the final reprocessed spectrum as received by a distant observer. We consider two extreme values of the black hole spin (a = 0 and a = 0.98) and discuss the dependence of the local and ray-traced spectra on the emission angle and black hole spin. Results: We show the importance of the angle dependence of the total disk specific intensity spectrum emitted by the illuminated atmosphere when the thermal disk emission is fully taken into account. The disk flux, together with the X-ray flux from the lamp, determines the temperature and ionization structure of the atmosphere. High black hole spin implies high temperature in the inner disk regions, therefore, the emitted thermal disk spectrum fully covers the iron-line complex. As a

  2. DISTRIBUTION OF HIGH-MASS X-RAY BINARIES IN THE MILKY WAY

    SciTech Connect

    Coleiro, Alexis; Chaty, Sylvain E-mail: chaty@cea.fr

    2013-02-20

    Observations of the high-energy sky, particularly with the INTEGRAL satellite, have quadrupled the number of supergiant X-ray binaries observed in the Galaxy and revealed new populations of previously hidden high-mass X-ray binaries (HMXBs), raising new questions about their formation and evolution. The number of detected HMXBs of different types is now high enough to allow us to carry out a statistical analysis of their distribution in the Milky Way. For the first time, we derive the distance and absorption of a sample of HMXBs using a spectral energy distribution fitting procedure, and we examine the correlation with the distribution of star-forming complexes (SFCs) in the Galaxy. We show that HMXBs are clustered with SFCs with a typical cluster size of 0.3 {+-} 0.05 kpc and a characteristic distance between clusters of 1.7 {+-} 0.3 kpc. Furthermore, we present an investigation of the expected offset between the position of spiral arms and HMXBs, allowing us to constrain age and migration distance due to supernova kick for 13 sources. These new methods will allow us to assess the influence of the environment on these high-energy objects with unprecedented reliability.

  3. On the origin of highly ionized X-ray absorbers detected in the galactic X-ray binaries

    SciTech Connect

    Luo, Yang; Fang, Taotao

    2014-01-10

    X-ray observations of the Galactic X-ray binaries (XRBs) revealed numerous highly ionized metal absorption lines. However, it is unclear whether such lines are produced by the hot interstellar medium (ISM) or the circumstellar medium intrinsic to the binaries. Here we present a Chandra X-ray absorption line study of 28 observations of 12 XRBs, with a focus on the Ne IX and Fe XVII lines. We report the first detections of these lines in a significant amount of observations. We do not find a significant dependence of the line equivalent width on the distance of the XRBs, but we do see a weak dependence on the source X-ray luminosity. We also find 2 out of 12 selected targets show strong temporal variation of the Ne IX absorbers. While the line ratio between the two ion species suggests a temperature consistent with the previous predictions of the ISM, comparing with two theoretical models of the ISM shows the observed column densities are significantly higher than predictions. On the other hand, photoionization by the XRBs provides a reasonably good fit to the data. Our findings suggest that a significant fraction of these X-ray absorbers may originate in the hot gas intrinsic to the XRBs, and that the ISM makes small, if not negligible, contribution. We briefly discuss the implications to the study of the Milky Way hot gas content.

  4. GALACTIC ULTRACOMPACT X-RAY BINARIES: DISK STABILITY AND EVOLUTION

    SciTech Connect

    Heinke, C. O.; Ivanova, N.; Engel, M. C.; Pavlovskii, K.; Sivakoff, G. R.; Gladstone, J. C.; Cartwright, T. F.

    2013-05-10

    We study the mass-transfer rates and disk stability conditions of ultracompact X-ray binaries (UCXBs) using empirical time-averaged X-ray luminosities from Paper I and compiled information from the literature. The majority of UCXBs are consistent with evolutionary tracks for white dwarf donors. Three UCXBs with orbital periods longer than 40 minutes have mass-transfer rates above 10{sup -10} M{sub Sun} yr{sup -1}, inconsistent with white dwarf donor tracks. We show that if helium star donors can retain their initial high entropy, they can explain the observed mass-transfer rates of these UCXBs. Several UCXBs show persistent luminosities apparently below the disk instability limit for irradiated He accretion disks. We point out that a predominantly C and/or O disk (as observed in the optical spectra of several) lowers the disk instability limit, explaining this disagreement. The orbital period and low time-averaged mass-transfer rate of 2S 0918-549 provide evidence that the donor star is a low-entropy C/O white dwarf, consistent with optical spectra. We combine existing information to constrain the masses of the donors in 4U 1916-053 (0.064 {+-} 0.010 M{sub Sun }) and 4U 1626-67 (<0.036 M{sub Sun} for a 1.4 M{sub Sun} neutron star). We show that 4U 1626-67 is indeed persistent, and not undergoing a transient outburst, leaving He star models as the best explanation for the donor.

  5. Unsupervised spectral decomposition of X-ray spectra from galactic black hole X-ray binary GX 339-4

    NASA Astrophysics Data System (ADS)

    Koljonen, K.

    2014-07-01

    Modelling the X-ray spectra of accreting black holes often leads to a problem of degeneracy, i.e. multiple distinct models fit the observed data equally well. Even if an apparently good fit is obtained between the data and the model, it does not necessarily imply a match between theory and physical reality. We separate a multivariate signal -- a set of time series of X-ray spectra -- into subcomponents, using linear unsupervised decomposition methods. This analysis will provide a better estimate of the X-ray continuum models needed to fit the X-ray spectra in these sources by taking into an account also the spectral variability in addition to the fitting of the individual spectra. A comparison with the different analysis methods are studied and suggestions made for the future use of these methods in the context of this study. We apply these analysis methods to an archival set of X-ray spectra from a stellar mass black hole X-ray binary GX 339-4. With a sufficiently long set of observations throughout the hardness-intensity diagram (HID) from GX 339-4, the use of unsupervised decomposition methods reveal how the spectral components change across the HID. We will discuss the ramifications of these results.

  6. Supergiant fast X-ray transients as an under-luminous class of supergiant X-ray binaries

    NASA Astrophysics Data System (ADS)

    Bozzo, E.; Romano, P.; Ducci, L.; Bernardini, F.; Falanga, M.

    2015-02-01

    The usage of cumulative luminosity distributions, constructed thanks to the long-term observations available through wide field hard X-ray imagers, has been recently exploited to study the averaged high energy emission (>17 keV) from supergiant fast X-ray transients (SFXTs) and classical Supergiant High Mass X-ray Binaries (SgXBs). Here, we take advantage of the long term monitorings now available with Swift/XRT to construct for the first time the cumulative luminosity distributions of a number of SFXTs and the classical SgXB IGR J18027-2016 in the soft X-ray domain with a high sensitivity focusing X-ray telescope (0.3-10 keV). By complementing previous results obtained in the hard X-rays, we found that classical SgXBs are characterized by cumulative distributions with a single knee around ∼ 1036-1037 erg s-1, while SFXTs are found to be systematically sub-luminous and their distributions are shifted at significantly lower luminosities (a factor of ∼ 10-100). As the luminosity states in which these sources spend most of their time are typically below the sensitivity limit of large field of view hard X-ray imagers, we conclude that soft X-ray monitorings carried out with high sensitivity telescopes are particularly crucial to reconstruct the complete profile of the SFXT cumulative luminosity distributions. The difference between the cumulative luminosity distributions of classical SgXBs and SFXTs is interpreted in terms of accretion from a structured wind in the former sources and the presence of magnetic/centrifugal gates or a quasi-spherical settling accretion regime in the latter.

  7. Globular Cluster Formation Efficiencies from Black Hole X-Ray Binary Feedback

    NASA Astrophysics Data System (ADS)

    Justham, Stephen; Peng, Eric W.; Schawinski, Kevin

    2015-08-01

    We investigate a scenario in which feedback from black hole X-ray binaries (BHXBs) sometimes begins inside young star clusters before strong supernova (SN) feedback. Those BHXBs could reduce the gas fraction inside embedded young clusters while maintaining virial equilibrium, which may help globular clusters (GCs) to stay bound when SN-driven gas ejection subsequently occurs. Adopting a simple toy model with parameters guided by BHXB population models, we produce GC formation efficiencies consistent with empirically inferred values. The metallicity dependence of BHXB formation could naturally explain why GC formation efficiency is higher at lower metallicity. For reasonable assumptions about that metallicity dependence, our toy model can produce a GC metallicity bimodality in some galaxies without a bimodality in the field-star metallicity distribution.

  8. On the spin period distribution in Be/X-ray binaries

    SciTech Connect

    Cheng, Z.-Q.; Shao, Y.; Li, X.-D.

    2014-05-10

    There is a remarkable correlation between the spin periods of the accreting neutron stars (NSs) in Be/X-ray binaries (BeXBs) and their orbital periods. Recently, Knigge et al. showed that the distribution of the spin periods contains two distinct subpopulations peaked at ∼10 s and ∼200 s, respectively, and suggested that they may be related to two types of supernovae for the formation of the NSs, i.e., core-collapse and electron-capture supernovae. Here we propose that the bimodal spin period distribution is likely to be ascribed to different accretion modes of the NSs in BeXBs. When the NS tends to capture material from the warped, outer part of the Be star disk and experiences giant outbursts, a radiatively cooling dominated disk is formed around the NS, which spins up the NS and is responsible for the short-period subpopulation. In BeXBs that are dominated by normal outbursts or are persistent, the accretion flow is advection-dominated or quasi-spherical. The spin-up process is accordingly inefficient, leading to longer periods of the neuron stars. The potential relation between the subpopulations and the supernova mechanism is also discussed.

  9. X-Ray Binary Populations in a Cosmological Context, Including NuSTAR Predictions

    NASA Technical Reports Server (NTRS)

    Cardiff, Ann Hornschemeier

    2011-01-01

    The new ultradeep 4 Ms Chandra Deep Field South has afforded the deepest view ever of X-ray binary populations. We report on the latest results on both LMXB and HMXB evolution out to redshifts of approximately four, including comparison with the latest theoretical models, using this deepest-ever view of the X-ray universe with Chandra. The upcoming NuSTAR mission will open up X-ray binary populations in the hard X-ray band, similar to the pioneering work of Fabbiano et al. in the Einstein era. We report on plans to study both Local Group and starburst galaxies as well as the implications those observations may have for X-ray binary populations in galaxies contributing to the Cosmic X-ray Background.

  10. X-ray Observations of the Tycho Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Hughes, John P.

    2006-06-01

    In this presentation I summarize some key new findings from recent Chandra and XMM-Newton data on the remnant of the supernova (SN) observed by Tycho Brahe in 1572, which is widely believed to have been of Type Ia origin. Studies of the Tycho supernova remnant (SNR) at the current epoch address aspects of SN Ia physics, the evolution of young SNRs, and cosmic ray acceleration at high Mach-number shocks.Research on the Tycho SNR at Rutgers has been supported by Chandra grants GO3-4066X and AR5-6010X.

  11. Luminous Supersoft X-Ray Sources as Progenitors of Type Ia Supernovae

    NASA Technical Reports Server (NTRS)

    DiStefano, R.

    1996-01-01

    In some luminous supersoft X-ray sources, hydrogen accretes onto the surface of a white dwarf at rates more-or-less compatible with steady nuclear burning. The white dwarfs in these systems therefore have a good chance to grow in mass. Here we review what is known about the rate of Type la supernovae that may be associated with SSSS. Observable consequences of the conjecture that SSSs can be progenitors of Type Ia supernovae are also discussed.

  12. SXP 1062, a young Be X-ray binary pulsar with long spin period. Implications for the neutron star birth spin

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Sturm, R.; Filipović, M. D.; Pietsch, W.; Crawford, E. J.

    2012-01-01

    Context. The Small Magellanic Cloud (SMC) is ideally suited to investigating the recent star formation history from X-ray source population studies. It harbours a large number of Be/X-ray binaries (Be stars with an accreting neutron star as companion), and the supernova remnants can be easily resolved with imaging X-ray instruments. Aims: We search for new supernova remnants in the SMC and in particular for composite remnants with a central X-ray source. Methods: We study the morphology of newly found candidate supernova remnants using radio, optical and X-ray images and investigate their X-ray spectra. Results: Here we report on the discovery of the new supernova remnant around the recently discovered Be/X-ray binary pulsar CXO J012745.97-733256.5 = SXP 1062 in radio and X-ray images. The Be/X-ray binary system is found near the centre of the supernova remnant, which is located at the outer edge of the eastern wing of the SMC. The remnant is oxygen-rich, indicating that it developed from a type Ib event. From XMM-Newton observations we find that the neutron star with a spin period of 1062 s (the second longest known in the SMC) shows a very high average spin-down rate of 0.26 s per day over the observing period of 18 days. Conclusions: From the currently accepted models, our estimated age of around 10 000-25 000 years for the supernova remnant is not long enough to spin down the neutron star from a few 10 ms to its current value. Assuming an upper limit of 25 000 years for the age of the neutron star and the extreme case that the neutron star was spun down by the accretion torque that we have measured during the XMM-Newton observations since its birth, a lower limit of 0.5 s for the birth spin period is inferred. For more realistic, smaller long-term average accretion torques our results suggest that the neutron star was born with a correspondingly longer spin period. This implies that neutron stars in Be/X-ray binaries with long spin periods can be much younger

  13. Emission lines from X-ray-heated accretion disks in low-mass X-ray binaries

    NASA Technical Reports Server (NTRS)

    Ko, Yuan-Kuen; Kallman, Timothy R.

    1994-01-01

    We investigate the structure of accretion disks illuminated by X-rays from a central compact object in a binary system. X-rays can photoionize the upper atmosphere of the disk and form an accretion disk corona (ADC) where emission lines can form. We construct a model to calculate the vertical structure and the emission spectrum of the ADC with parameters appropriate to low-mass X-ray binaries. These models are made by nonlocal thermodynamic equilibrium calculations of ion and level populations and include a large number of atomic processes for 10 cosmically abundant elements. Transfer of radiation is treated by using the escape probability formalism. The vertical temperature profile of the ADC consists of a Compton-heated region and a mid-T zone where the temperature is approximately 10(exp 6) K. A thermal instability occurs close to the disk photosphere and causes the temperature of the ADC to drop abruptly from 10(exp 6) K to several times 10(exp 4) K. The emission spectrum in the optical, ultraviolet, extreme ultraviolet, and X-ray range is discussed and compared with the observations.

  14. Stellar feedback from high-mass X-ray binaries in cosmological hydrodynamical simulations

    NASA Astrophysics Data System (ADS)

    Artale, M. C.; Tissera, P. B.; Pellizza, L. J.

    2015-04-01

    We explored the role of X-ray binaries composed by a black hole and a massive stellar companion [black hole X-ray binaries (BHXs)] as sources of kinetic feedback by using hydrodynamical cosmological simulations. Following previous results, our BHX model selects metal-poor stars (Z = [0, 10-4]) as possible progenitors. The model that better reproduces observations assumes that an ˜20 per cent fraction of low-metallicity black holes are in binary systems which produces BHXs. These sources are estimated to deposit ˜1052 erg of kinetic energy per event. With these parameters and in the simulated volume, we find that the energy injected by BHXs represents ˜30 per cent of the total energy released by Type II supernova and BHX events at redshift z ˜ 7 and then decreases rapidly as baryons get chemically enriched. Haloes with virial masses smaller than ˜1010 M⊙ (or Tvir ≲ 105 K) are the most directly affected ones by BHX feedback. These haloes host galaxies with stellar masses in the range 107-108 M⊙. Our results show that BHX feedback is able to keep the interstellar medium warm, without removing a significant gas fraction, in agreement with previous analytical calculations. Consequently, the stellar-to-dark matter mass ratio is better reproduced at high redshift. Our model also predicts a stronger evolution of the number of galaxies as a function of the stellar mass with redshift when BHX feedback is considered. These findings support previous claims that the BHXs could be an effective source of feedback in early stages of galaxy evolution.

  15. CLUSTERING BETWEEN HIGH-MASS X-RAY BINARIES AND OB ASSOCIATIONS IN THE MILKY WAY

    SciTech Connect

    Bodaghee, A.; Tomsick, J. A.; Rodriguez, J.

    2012-01-10

    We present the first direct measurement of the spatial cross-correlation function of high-mass X-ray binaries (HMXBs) and active OB star-forming complexes in the Milky Way. This result relied on a sample containing 79 hard X-ray-selected HMXBs and 458 OB associations. Clustering between the two populations is detected with a significance above 7{sigma} for distances <1 kpc. Thus, HMXBs closely trace the underlying distribution of the massive star-forming regions that are expected to produce the progenitor stars of HMXBs. The average offset of 0.4 {+-} 0.2 kpc between HMXBs and OB associations is consistent with being due to natal kicks at velocities of the order of 100 {+-} 50 km s{sup -1}. The characteristic scale of the correlation function suggests an average kinematical age (since the supernova phase) of {approx}4 Myr for the HMXB population. Despite being derived from a global view of our Galaxy, these signatures of HMXB evolution are consistent with theoretical expectations as well as observations of individual objects.

  16. X-ray emission from the remnant of a carbon deflagration supernova - SN 1572 (Tycho)

    SciTech Connect

    Itoh, H.; Masai, K.; Nomoto, K.

    1988-11-01

    A spherically symmetric hydrodynamic code is used to study the evolution of a young supernova remnant on the basis of a carbon deflagration model for type Ia supernovae. The nonequilibrium X-ray emission has been determined for the elemental composition of the model. The discrepancy between the derived intensity of the Fe D-alpha line blend and the observed value is eliminated by assuming that the stratification of the elemental composition in the supernova ejecta is partially removed by mixing. 59 references.

  17. The Fall and Rise of X-ray Supernova 2005kd

    NASA Astrophysics Data System (ADS)

    Dwarkadas, Vikram; Reddy, Ratuja; Bauer, Franz E.

    2015-01-01

    Supernova (SN) 2005kd belongs to the class of Type IIn SNe, which show narrow lines in their early spectra. It is one of the most luminous X-ray SNe known - in excess of Lx = 1041 ergs/s at peak. The evolution of its X-ray luminosity with time is rather atypical, with a general dimming, as expected, followed by an unexpected re-brightening. We report on a recent 30 ks Chandra observation of SN 2005kd, which extends the X-ray lightcurve of this SN from 2005 to 2013. We use the time evolution of the X-ray flux to explore the expansion of the forward and reverse shock of the SN within the surrounding medium, as well as to study the structure of the surrounding medium.

  18. Studying X-Ray Binaries with High Energy Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Kaaret, P.

    2003-01-01

    The goal of this investigation is to further our understanding of the dynamics of accreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fields. The main focus of this work has been a multi-year program of simultaneous millisecond x-ray timing and spectral observations carried out with the Rossi X-Ray Timing Explorer (RXTE) to perform the x-ray timing and one of the satellites Asca, BeppoSAX, or Chandra to perform x-ray spectral measurements. With the advent of Chandra, we have extended our work to include imaging of X-ray jets from binaries and the study of extragalactic X-ray binaries. Significant progress was made over the past year.

  19. Simultaneous radio and X-ray observations of Galactic Centre low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Berendsen, Stephan G. H.; Fender, Robert; Kuulkers, Erik; Heise, J.; van der Klis, M.

    2000-10-01

    We have performed simultaneous X-ray and radio observations of 13 Galactic Centre low-mass X-ray binaries in 1998 April using the Wide Field Cameras on board BeppoSAX and the Australia Telescope Compact Array, the latter simultaneously at 4.8 and 8.64GHz. We detect two Z sources, GX 17+2 and GX 5-1, and the unusual `hybrid' source GX 13+1. Upper limits, which are significantly deeper than previous non-detections, are placed on the radio emission from two more Z sources and seven atoll sources. Hardness-intensity diagrams constructed from the Wide Field Camera data reveal GX 17+2 and GX 5-1 to have been on the lower part of the horizontal branch and/or the upper part of the normal branch at the time of the observations, and the two non-detected Z sources, GX 340+0 and GX 349+2, to have been on the lower part of the normal branch. This is consistent with the previous empirically determined relation between radio and X-ray emission from Z sources, in which radio emission is strongest on the horizontal branch and weakest on the flaring branch. For the first time we have information on the X-ray state of atoll sources, which are clearly radio-quiet relative to the Z sources, during periods of observed radio upper limits. We place limits on the linear polarization from the three detected sources, and use accurate radio astrometry of GX 17+2 to confirm that it is probably not associated with the optical star NP Ser. Additionally we place strong upper limits on the radio emission from the X-ray binary 2S 0921-630, disagreeing with suggestions that it is a Z-source viewed edge-on.

  20. Chandra Observation of Luminous and Ultraluminous X-ray Binaries in M101

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Pence, W. D.; Snowden, S. L.; Kuntz, K. D.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    X-ray binaries in the Milky Way are among the brightest objects on the X-ray sky. With the increasing sensitivity of recent missions, it is now possible to study X-ray binaries in nearby galaxies. We present data on six ultraluminous binaries in the nearby spiral galaxy, M101, obtained with Chandra ACIS-S. Of these, five appear to be similar to ultraluminous sources in other galaxies, while the brightest source, P098, shows some unique characteristics. We present our interpretation of the data in terms of an optically thick outflow, and discuss implications.

  1. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni during Quiescence

    NASA Astrophysics Data System (ADS)

    Rana, Vikram; Loh, Alan; Corbel, Stephane; Tomsick, John A.; Chakrabarty, Deepto; Walton, Dominic J.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William; Fuerst, Felix; Gandhi, Poshak; Grefenstette, Brian W.; Hailey, Charles; Harrison, Fiona A.; Madsen, Kristin K.; Rahoui, Farid; Stern, Daniel; Tendulkar, Shriharsh; Zhang, William W.

    2016-04-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0.3–30 keV) quiescent luminosity of the source is 8.9 × 1032 erg s‑1 for a distance of 2.4 kpc. The source shows clear variability on short timescales (an hour to a couple of hours) in the radio, soft X-ray, and hard X-ray bands in the form of multiple flares. The broadband X-ray spectra obtained from XMM-Newton and NuSTAR can be characterized with a power-law model having a photon index of Γ = 2.12 ± 0.07 (90% confidence errors); however, residuals at high energies indicate spectral curvature significant at a 3σ confidence level with the e-folding energy of the cutoff as {20}-7+20 keV. Such curvature can be explained using synchrotron emission from the base of a jet outflow. Radio observations using the VLA reveal that the spectral index evolves on very fast timescales (as short as 10 minutes), switching between optically thick and thin synchrotron emission, possibly due to instabilities in the compact jet or stochastic instabilities in the accretion rate. We explore different scenarios to explain this very fast variability.

  2. The X-ray emission from Type IIn Supernovae as a Probe of the Stellar Environment and Supernova Progenitors

    NASA Astrophysics Data System (ADS)

    Dwarkadas, Vikram

    2016-04-01

    Core-collapse supernovae (SNe) are divided into different subclasses, depending mainly on their optical spectra or light curve. Type IIn supernovae (SNe) form one of the more recent subclasses, having been first identified in 1990. They are characterized by narrow lines on a broad base in the optical spectrum, and comprise 1 to 4% of the total core collapse SN population. There exists a wide diversity in SNe that exhibit IIn features, which has greatly complicated the task of identifying their progenitors.IIns are observed to have the highest X-ray luminosity of all the SN classes, with luminosities generally exceeding 1038 ergs/s after several thousand days. Thus they are observable in X-rays even at late times, hundreds to thousands of days after explosion. They also exhibit the most diversity in their light curves. Many of the lightcurves tend to fall off rather steeply at late times, although one interesting case displayed a rising light curve for several thousand days. These characteristics, along with their high luminosities at other wavelengths, imply initial expansion in a very dense medium, with the densities decreasing rapidly a few years after explosion. Their X-ray spectra generally show distinct lines, suggesting that the emission is thermal in origin. The X-ray spectra can provide insight into the density structure, composition and metallicity of the surrounding medium, and the ionization level, through the spectra themselves as well as the X-ray absorption.In this presentation we will show the lightcurves of almost all IIns that have been observed in the X-ray band, and compare and contrast them to the X-ray lightcurves of other types of SNe. We summarize the known properties of the X-ray emission from Type IIn SNe, and explore the implications for the SN environment, progenitor mass-loss and the identity of the progenitors.

  3. Measuring The Distances, Masses, and Radii of Neutron Stars In X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Guver, Tolga; Ozel, F.; Cabrera-Lavers, A.

    2010-03-01

    Low mass X-ray binaries that have independent distance measurements and show thermonuclear X-ray bursts are ideal sources for constraining the equation of state of neutron star matter. I will introduce our program to systematically measure the distances, masses, and radii of neutron stars in such binaries. We utilize high energy resolution X-ray spectra to measure the ISM column densities to these sources as well as time resolved, high count rate X-ray spectra to study their bursts. I will discuss in detail how the combination of these observations have led to the measurement of the masses and radii of the neutron stars in the low mass X-ray binaries EXO 1745-248, 4U 1608-52, and 4U 1820-30.

  4. The Soft X-ray Spectrum of the High Mass X-Ray Binary V0332+53 in Quiescence

    NASA Astrophysics Data System (ADS)

    Elshamouty, Khaled G.; Heinke, Craig O.; Chouinard, Rhys

    2016-08-01

    The behaviour of neutron stars in high mass X-ray binaries (HMXBs) during periods of low mass transfer is of great interest. Indications of spectral softening in systems at low mass transfer rates suggest that some HMXBs are undergoing fundamental changes in their accretion regime, but the nature of the quiescent X-ray emission is not clear. We performed a 39 ks XMM-Newton observation of the transient HMXB V0332+53, finding it at a very low X-ray luminosity (Lx ˜ 4 × 1032 erg s-1). A power-law spectral fit requires an unusually soft spectral index (4.4^{+0.9}_{-0.6}), while a magnetized neutron star atmosphere model, with temperature LogTeff 6.7±0.2 K and inferred emitting radius of ˜0.2 - 0.3 km, gives a good fit. We suggest that the quiescent X-ray emission from V0332+53 is mainly from a hot spot on the surface of the neutron star. No conclusions on the presence of pulsations could be drawn due to the low count rate. Due to the high absorption column, thermal emission from the rest of the neutron star could be only weakly constrained, to LogTeff <6.14^{+0.05}_{-6.14} K, or <3 × 1033 erg s-1.

  5. Recent Radio Results on X-ray Binaries and Transients

    NASA Astrophysics Data System (ADS)

    Rupen, M. P.; Dhawan, V.; Mioduszewski, A. J.

    2003-03-01

    We present recent results from observations with the Very Large Array (VLA) and Very Long Baseline Array (VLBA) on a number of recent X-ray transients, and a few old friends. In addition to any new X-ray transients discovered between now and the HEAD meeting, we discuss the radio counterpart to XTE J1720-318; the recent resurgence of XTE J1908+094 and GRS 1758-258; the connection between the radio and X-ray emission in the millisecond X-ray pulsars XTE J0929-314 and SAX J1808.4-3658; and VLBA imaging of the 1999 outburst of the microquasar V4641 Sgr, confirming the rapid expansion seen with the VLA. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  6. Recognition of binary x-ray systems utilizing the doppler effect

    NASA Technical Reports Server (NTRS)

    Novak, B. L.

    1980-01-01

    The possibility of recognizing the duality of a single class of X-ray systems utilizing the Doppler effect is studied. The procedure is based on the presence of a period which coincides with the orbital period at the intensity of the radiation in a fixed energy interval of the X-ray component of a binary system.

  7. Constraining the formation of black holes in short-period black hole low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Repetto, Serena; Nelemans, Gijs

    2015-11-01

    The formation of stellar-mass black holes (BHs) is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova (SN) event (if any) and the magnitude of the natal kick (NK) the BH receives at birth (if any). Repetto et al., studying the position of Galactic X-ray binaries containing BHs, found evidence for BHs receiving high NKs at birth. In this paper, we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period BH X-ray binaries that we use are compact binaries consisting of a low-mass star orbiting a BH in a period less than 1 d. We trace their binary evolution backwards in time, from the current observed state of mass transfer, to the moment the BH was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no NK, just mass ejection, while for two systems (and possibly more) a high kick is required. So unless the latter have an alternative formation, such as within a globular cluster, we conclude that at least some BHs get high kicks. This challenges the standard picture that BH kicks would be scaled down from neutron star kicks. Furthermore, we find that five systems could have formed with a non-zero NK but zero mass ejected (i.e. no SN) at formation, as predicted by neutrino-driven NKs.

  8. X-Ray Illumination of the Ejecta of Supernova 1987A

    NASA Technical Reports Server (NTRS)

    Larsson, J.; Fransson, C.; Oestlin, G.; Groeningsson, P.; Jerkstrand, A.; Kozma, C.; Sollerman, J.; Challis, P.; Kirshner, R. P.; Chevalier, R. A.; Heng, K.; McCray, R.; Suntzeff, N. B.; Bouchet, P.; Crotts, A.; Danziger, J.; Dwek, E.; France, K.; Garnavich, P. M.; Lawrence, S. S.; Leibundgut, B.; Lundqvist, P.; Panagia, N.; Pun, C. S. J.; Sonneborn, G.

    2011-01-01

    When a massive star explodes as a supernova, substantial amounts of radioactive elements-primarily Ni-56, Ni-57 and Ti-44 are produced. After the initial from shock heating, the light emitted by the supernova is due to the decay of these elements. However, after decades, the energy powering a supernova remnant comes from the shock interaction between the ejecta and the surrounding medium. The transition to this phase has hitherto not been observed: supernovae occur too infrequently in the Milky Way to provide a young example, and extragalactic supernovae are generally too faint and too small. Here we report observations that show this transition in the supernova SN 1987A in the Large Magellan Cloud. From 1994 to 200l, the ejecta faded owing to radioactive decay of Ti-44 as predicted. Then the flux started to increase, more than doubling by the end of 2009. We show that this increase is the result of heat deposited by X-rays produced as the ejecta interacts with the surrounding material. In time, the X-rays will penetrate farther into the ejects, enabling us to analyse the structure and chemistry of the vanished star.

  9. X-ray illumination of the ejecta of supernova 1987A.

    PubMed

    Larsson, J; Fransson, C; Ostlin, G; Gröningsson, P; Jerkstrand, A; Kozma, C; Sollerman, J; Challis, P; Kirshner, R P; Chevalier, R A; Heng, K; McCray, R; Suntzeff, N B; Bouchet, P; Crotts, A; Danziger, J; Dwek, E; France, K; Garnavich, P M; Lawrence, S S; Leibundgut, B; Lundqvist, P; Panagia, N; Pun, C S J; Smith, N; Sonneborn, G; Wang, L; Wheeler, J C

    2011-06-23

    When a massive star explodes as a supernova, substantial amounts of radioactive elements--primarily (56)Ni, (57)Ni and (44)Ti--are produced. After the initial flash of light from shock heating, the fading light emitted by the supernova is due to the decay of these elements. However, after decades, the energy powering a supernova remnant comes from the shock interaction between the ejecta and the surrounding medium. The transition to this phase has hitherto not been observed: supernovae occur too infrequently in the Milky Way to provide a young example, and extragalactic supernovae are generally too faint and too small. Here we report observations that show this transition in the supernova SN 1987A in the Large Magellanic Cloud. From 1994 to 2001, the ejecta faded owing to radioactive decay of (44)Ti as predicted. Then the flux started to increase, more than doubling by the end of 2009. We show that this increase is the result of heat deposited by X-rays produced as the ejecta interacts with the surrounding material. In time, the X-rays will penetrate farther into the ejecta, enabling us to analyse the structure and chemistry of the vanished star. PMID:21654749

  10. ON NEUTRAL ABSORPTION AND SPECTRAL EVOLUTION IN X-RAY BINARIES

    SciTech Connect

    Miller, J. M.; Cackett, E. M.; Reis, R. C.

    2009-12-10

    Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low-energy portion of the spectrum should be attributed to evolution in the source, or instead to evolution in neutral photoelectric absorption. Dispersive spectrometers make it possible to address this problem. We have analyzed a small but diverse set of X-ray binaries observed with the Chandra High Energy Transmission Grating Spectrometer across a range in luminosity and different spectral states. The column density in individual photoelectric absorption edges remains constant with luminosity, both within and across source spectral states. This finding suggests that absorption in the interstellar medium strongly dominates the neutral column density observed in spectra of X-ray binaries. Consequently, evolution in the low-energy spectrum of X-ray binaries should properly be attributed to evolution in the source spectrum. We discuss our results in the context of X-ray binary spectroscopy with current and future X-ray missions.

  11. Spatially resolved X-ray line spectroscopy of Tycho's supernova remnant

    NASA Technical Reports Server (NTRS)

    Gotthelg, Eric V.; Hwang, Una

    1996-01-01

    Narrow band X-ray images of Tycho's supernova remnant, acquired with the solid-state spectrometer onboard the Advanced Satellite for Cosmology and Astrophysics (ASCA), are presented. The remnant is mapped in several prominent emission lines and in the 1.4 keV to 1.7 keV and 4 keV to 6 keV continua. A spatial resolution of approximately 0.5 min was obtained. No significant correlation was found for Tycho between the X-ray 4 keV to 6 keV continuum and the radio morphology.

  12. The x-ray structure of the supernova remnant W49B

    NASA Technical Reports Server (NTRS)

    Dickel, John R.; Murphy, Rosa; Chu, You-Hua; Garcia, Guillermo; Goscha, Daniel

    1994-01-01

    Comparison of x-ray and radio images of W49B and other supernova remnants (SNR) provides detailed information on the mechanisms responsible for the emission and on the evolution of the remnants. There is faint x-ray emission from all parts of W49B but most of it is concentrated near the center of the remnant, unlike the radio emission which arises in a shell near the periphery. This structure indicates that this SNR is in the adolescent phase of its lifetime.

  13. A Study of Supernova Remnants with Center-Filled X-Ray Morphology

    NASA Technical Reports Server (NTRS)

    Slane, Patrick O.

    2001-01-01

    The proposed study entails use of archival data, primarily from past and active X-ray observatories, to study the properties of a class of supernova remnants (SNRs) which display a centrally-bright X-ray morphology. Several models which have been proposed to explain the morphology are being investigated for comparisons with measured characteristics of several remnants: nonthermal emission from a central synchrotron nebula; thermal emission enhanced by slow evaporation of cool clouds in the hot SNR interior; and relic thermal emission from the SNR interior after the remnant has entered the radiative phase of evolution, thus causing the shell emission to cease.

  14. Soft X-ray emission from the Lupus Loop and Sn 1006 supernova remnants

    NASA Technical Reports Server (NTRS)

    Winkler, P. F., Jr.; Hearn, D. R.; Richardson, J. A.; Behnken, J. M.

    1979-01-01

    X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint extended source of soft X-rays with a temperature about 2.5 million K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2-1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star.

  15. Origin and evolution of X-ray binaries in globular clusters

    NASA Technical Reports Server (NTRS)

    Grindlay, Jonathan E.

    1986-01-01

    The theoretical model developed by Grindlay (1984 and 1985) and Grindlay and Hertz (1985) to explain the relative numbers of low-luminosity and high-luminosity X-ray sources in Galactic globular clusters is briefly characterized, and the relevant observational evidence is summarized. In the model, high-rate mass transfer onto white dwarfs in about 1 percent of the low-luminosity binary sources produces neutron stars, which then form compact high-luminosity X-ray binaries (by tidal capture in the dense cluster cores); these in turn evolve into hierarchical triple systems. Evidence considered includes observations of the high-luminosity giant-fed X-ray binary in M 15, the results of searches for CVs in globulars, comparisons of X-ray-binary and host-globular evolution, and indications that GX 17 + 2 is a bound triple.

  16. VizieR Online Data Catalog: X-ray and radio sources in binaries (Malkov+, 2015)

    NASA Astrophysics Data System (ADS)

    Malkov, O. Y.; Tessema, S. B.; Kniazev, A. Y.

    2016-05-01

    We have also compiled a general list of 239 radio pulsars in binary systems. The list is supplied with indication of photometric, spectroscopic or X-ray binarity, and with cross-identification data. (4 data files).

  17. On double-degenerate type Ia supernova progenitors as supersoft X-ray sources. A population synthesis analysis using SeBa

    NASA Astrophysics Data System (ADS)

    Nielsen, M. T. B.; Nelemans, G.; Voss, R.; Toonen, S.

    2014-03-01

    Context. The nature of the progenitors of type Ia supernova progenitors remains unclear. While it is usually agreed that single-degenerate progenitor systems would be luminous supersoft X-ray sources, it was recently suggested that double-degenerate progenitors might also go through a supersoft X-ray phase. Aims: We aim to examine the possibility of double-degenerate progenitor systems being supersoft X-ray systems, and place stringent upper limits on the maximally possible durations of any supersoft X-ray source phases and expected number of these systems in a galactic population. Methods: We employ the binary population synthesis code SeBa to examine the mass-transfer characteristics of a possible supersoft X-ray phase of double-degenerate type Ia supernova progenitor systems for 1) the standard SeBa assumptions; and 2) an optimistic best-case scenario. The latter case establishes firm upper limits on the possible population of supersoft source double-degenerate type Ia supernova progenitor systems. Results: Our results indicate that unlike what is expected for single-degenerate progenitor systems, the vast majority of the material accreted by either pure wind mass transfer or a combination of wind and RLOF mass transfer is helium rather than hydrogen. Even with extremely optimistic assumptions concerning the mass-transfer and retention efficiencies, the average mass accreted by systems that eventually become double-degenerate type Ia supernovae is small. Consequently, the lengths of time that these systems may be supersoft X-ray sources are short, even under optimal conditions, and the expected number of such systems in a galactic population is negligible. Conclusions: The population of double-degenerate type Ia supernova progenitors that are supersoft X-ray sources is at least an order of magnitude smaller than the population of single-degenerate progenitors expected to be supersoft X-ray sources, and the supersoft X-ray behaviour of double-degenerate systems

  18. Studying Young and Old Supernova Remnants with the Upcoming ASTRO-H X-ray Mission

    NASA Astrophysics Data System (ADS)

    Safi-Harb, Samar; Hughes, John P.; Long, Knox; Bamba, Aya; Aharonian, Felix; Foster, Adam; Funk, Stefan; Hiraga, Junko; Ishida, Manabu; Katsuda, Satoru; Koyama, Katsuji; Leutenegger, Maurice; Maeda, Yoshitomo; Matsumoto, Hironori; Mori, Koji; Nakajima, Hiroshi; Nakamori, Takashi; Nobukawa, Masayoshi; Ozaki, Masanobu; Petre, Robert; Sawada, Makoto; Tamagawa, Toru; Tamura, Keisuke; Tanaka, Takaaki; Tomida, Hiroshi; Tsunemi, Hiroshi; Uchida, Hiroyuki; Uno, Shin'ichiro; Uchiyama, Yasunobu; Yamaguchi, Hiroya; Yamauchi, Shigeo; ASTRO-H Science Working Group

    2015-01-01

    The upcoming X-ray mission ASTRO-H will open a new discovery window to the high-energy Universe thanks to the unprecedented high-resolution spectroscopy (~7eV) to be achieved with the Soft X-ray Spectrometer (SXS) combined with its broadband coverage (0.5-600 keV) with the Soft X-ray Imager (SXI), Hard X-ray Imager (HXI) and the Soft Gamma-ray Detector (SGD). Supernova remnants (SNRs) are a prime science focus for ASTRO-H, particularly with the SXS providing accurate plasma diagnostics of line-rich spectra expected from the youngest, ejecta-dominated, SNRs to the oldest SNRs impacted by their interaction with the Interstellar Medium (ISM). We here highlight the SNR science topics and program that the ASTRO-H team considers of highest priority and impact. For the younger SNRs, the primary science goals are (1) using abundance measurements to unveil SNR progenitors, (2) using spatial and velocity distribution of the ejecta to understand supernova explosion mechanisms, and (3) revealing the link between the thermal plasma state of SNRs and the efficiency of their particle acceleration. For the older SNRs where thermal emission is dominated or heavily impacted by the ISM, the primary goals are (1) constraining metal abundances and physical processes in the mature limb-brightened SNRs, and (2) understanding the puzzling nature of the `mixed-morphology' SNRs and the physics of recombining plasma. For the pulsar-powered nebulae, also known as Pulsar Wind Nebulae (PWNe) or plerions with many still lacking thermal X-ray emission from their supernova shells, ASTRO-H will shed light on their progenitors and environment. The hard X-ray coverage on board ASTRO-H will further allow a study of their broadband spectra (for the brightest objects), beyond NuSTAR's range, filling the gap between the soft X-ray regime (with current X-ray missions) and the gamma-ray regime (with Fermi in the GeV and H.E.S.S. in the TeV), allowing the search for spectral breaks in the hard X-ray band.

  19. Supernova Remnants in the Sedov Expansion Phase: Thermal X-Ray Emission

    NASA Astrophysics Data System (ADS)

    Borkowski, Kazimierz J.; Lyerly, William J.; Reynolds, Stephen P.

    2001-02-01

    Improved calculations of X-ray spectra for supernova remnants (SNRs) in the Sedov-Taylor phase are reported, which for the first time include reliable atomic data for Fe L-shell lines. This new set of Sedov models also allows for a partial collisionless heating of electrons at the blast wave and for energy transfer from ions to electrons through Coulomb collisions. X-ray emission calculations are based on the updated Hamilton-Sarazin spectral model. The calculated X-ray spectra are successfully interpreted in terms of three distribution functions: the electron temperature and ionization timescale distributions, and the ionization timescale-averaged electron temperature distribution. The comparison of Sedov models with a frequently used single nonequilibrium ionization (NEI) timescale model reveals that this simple model is generally not an appropriate approximation to X-ray spectra of SNRs. We find instead that plane-parallel shocks provide a useful approximation to X-ray spectra of SNRs, particularly for young SNRs. Sedov X-ray models described here, together with simpler plane shock and single-ionization timescale models, have been implemented as standard models in the widely used XSPEC v11 spectral software package.

  20. Centaurus X-3. [early x-ray binary star spectroscopy

    NASA Technical Reports Server (NTRS)

    Hutchings, J. B.; Cowley, A. P.; Crampton, D.; Van Paradus, J.; White, N. E.

    1979-01-01

    Spectroscopic observations of Krzeminski's star at dispersions 25-60 A/mm are described. The primary is an evolved star of type O6-O8(f) with peculiarities, some of which are attributable to X-ray heating. Broad emission lines at 4640A (N III), 4686 A(He II) and H-alpha show self-absorption and do not originate entirely from the region near the X-ray star. The primary is not highly luminous (bolometric magnitude about -9) and does not show signs of an abnormally strong stellar wind. The X-ray source was 'on' at the time of optical observations. Orbital parameters are presented for the primary, which yield masses of 17 + or - 2 and 1.0 + or - 3 solar masses for the stars. The optical star is undermassive for its luminosity, as are other OB-star X-ray primaries. The rotation is probably synchronized with the orbital motion. The distance to Cen X-3 is estimated to be 10 + or - 1 kpc. Basic data for 12 early-type X-ray primaries are discussed briefly

  1. BLACK HOLE SPIN-ORBIT MISALIGNMENT IN GALACTIC X-RAY BINARIES

    SciTech Connect

    Fragos, T.; Tremmel, M.; Rantsiou, E.; Belczynski, K. E-mail: michaeltremmel2007@u.northwestern.ed E-mail: kbelczyn@nmsu.ed

    2010-08-10

    In black hole (BH) X-ray binaries (XRBs), a misalignment between the spin axis of the BH and the orbital angular momentum can occur during the supernova explosion that forms the compact object. In this Letter, we present population synthesis (PS) models of Galactic BH XRBs and study the probability density function of the misalignment angle and its dependence on our model parameters. In our modeling, we also take into account the evolution of the misalignment angle due to accretion of material onto the BH during the XRB phase. The major factor that sets the misalignment angle for XRBs is the natal kick that the BH may receive at its formation. However, large kicks tend to disrupt binaries, while small kicks allow the formation of XRBs and naturally select systems with small misalignment angles. Our calculations predict that the majority (>67%) of Galactic field BH XRBs have rather small ({approx}<10{sup 0}) misalignment angles, while some systems may reach misalignment angles as high as {approx}90{sup 0} and even higher. These results are robust among all PS models. The assumption of small misalignment angles is extensively used to observationally estimate BH spin magnitudes, and for the first time we are able to confirm this assumption using detailed PS calculations.

  2. The Peculiar Galactic Center Neutron Star X-Ray Binary XMM J174457-2850.3

    NASA Technical Reports Server (NTRS)

    Degenaar, N.; Wijnands, R.; Reynolds, M. T.; Miller, J. M.; Altamirano, D.; Kennea, J.; Gehrels, N.; Haggard, D.; Ponti, G.

    2014-01-01

    The recent discovery of a milli-second radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially serve as a template to search for other X-ray binary radio pulsar transitional objects. Here we demonstrate that the transient X-ray source XMM J174457-2850.3 near the Galactic center displays similar X-ray properties. We report on the detection of an energetic thermonuclear burst with an estimated duration of 2 hr and a radiated energy output of 5E40 erg, which unambiguously demonstrates that the source harbors an accreting neutron star. It has a quiescent X-ray luminosity of Lx5E32 ergs and exhibits occasional accretion outbursts during which it brightens to Lx1E35-1E36 ergs for a few weeks (2-10 keV). However, the source often lingers in between outburst and quiescence at Lx1E33-1E34 ergs. This unusual X-ray flux behavior and its relatively hard X-ray spectrum, a power law with an index of 1.4, could possibly be explained in terms of the interaction between the accretion flow and the magnetic field of the neutron star.

  3. Sigma observations of the low mass X-ray binaries of the galactic bulge

    NASA Technical Reports Server (NTRS)

    Goldwurm, A.; Denis, M.; Paul, J.; Faisse, S.; Roques, J. P.; Bouchet, L.; Vedrenne, G.; Mandrou, P.; Sunyaev, R.; Churazov, E.

    1995-01-01

    The soft gamma-ray telescope (35-1300 keV) SIGMA aboard the high energy GRANAT space observatory has been monitoring the Galactic Bulge region for more than 2000 h of effective time since March 1990. In the resulting average 35-75 keV image we detected ten sources at a level of greater than 5 standard deviations, 6 of which can be identified with low mass X-ray binaries (LMXB). Among them, one is the 1993 X-ray nova in Ophiuchus (GRS 1726-249), one is an X-ray pulsar (GX 1+4), two are associated with X-ray bursters (GX 354-0 and A 1742-294) and two with bursting X-ray binaries in the globular clusters Terzan 2 and Terzan 1. Their spectral and long term variability behavior as measured by SIGMMA are presented and discussed.

  4. Accretion disc atmospheres and winds in low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Díaz Trigo, M.; Boirin, L.

    2016-05-01

    In the last decade, X-ray spectroscopy has enabled a wealth of discoveries of photoionised absorbers in X-ray binaries. Studies of such accretion disc atmospheres and winds are of fundamental importance to understand accretion processes and possible feedback mechanisms to the environment. In this work, we review the current observational state and theoretical understanding of accretion disc atmospheres and winds in low-mass X-ray binaries, focusing on the wind launching mechanisms and on the dependence on accretion state. We conclude with issues that deserve particular attention.

  5. A Study of Supernova Remnants with Center-Filled X-Ray Morphology

    NASA Technical Reports Server (NTRS)

    Slane, Patrick O.

    1997-01-01

    CTA 1 is a center-filled supernova remnant (SNR) whose morphology and spectrum indicate the presence of a central pulsar, a synchrotron nebula, and a thermal component associated with the expansion of the blast wave into the interstellar medium. The centrally bright emission surrounds the position of a faint point source of x-rays observed with the ROSAT PSPC. Here we report on ASCA observations that confirm the nonthermal nature of the diffuse emission from the central regions of the remnant. We also present evidence for weak thermal emission that appears to increase in strength toward the outer boundary of the SNR. Thus, CTA 1 appears to be an x-ray composite remnant. Both the aftermath of the explosive supernova event and the energetic compact core are observable.

  6. The Environment of X-Ray Binaries in the Dwarf Starburst Galaxy NGC 1569

    NASA Astrophysics Data System (ADS)

    Clark, David M.; Eikenberry, Stephen S.; Raines, Steven N.

    2008-05-01

    We use deep, J and Ks observations of NGC 1569 acquired with FLAMINGOS on the KPNO 4-m to search for star cluster counterparts to X-ray binaries identified in archived Chandra images of this dwarf starburst galaxy. Performing near-IR photometry on the star cluster counterparts, we determine their colors, luminosities and masses. Comparing these results to the properties for all clusters in this galaxy, we search for trends in clusters associated with X-ray sources. Combining this study with FISICA, near-IR spectral observations, we further characterize the surroundings to X-ray binaries in NGC 1569. Contrasting this work with findings from a similar study performed on the Antennae galaxies, a large, merging system, we investigate the differences in X-ray binary environments.

  7. The End of Days -- Chandra Catches X-ray Glow From Supernova

    NASA Astrophysics Data System (ADS)

    1999-12-01

    Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

  8. On binary driven hypernovae and their nested late X-ray emission

    NASA Astrophysics Data System (ADS)

    Muccino, Marco; Ruffini, Remo; Bianco, Carlo Luciano; Enderli, Maxime; Kovacevic, Milos; Izzo, Luca; Penacchioni, Ana Virginia; Pisani, Giovanni Battista; Rueda, Jorge A.; Wang, Yu

    2015-07-01

    The induced gravitational collapse (IGC) paradigm addresses energetic (1052-1054 erg), long gamma-ray bursts (GRBs) associated to supernovae (SNe) and proposes as their progenitors tight binary systems composed of an evolved FeCO core and a companion neutron star (NS). Their emission is characterized by four specific episodes: Episode 1, corresponding to the on-set of the FeCO SN explosion and the accretion of the ejecta onto the companion NS; Episode 2, related the collapse of the companionNS to a black hole (BH) and to the emission of a long GRB; Episode 3, observed in X-rays and characterized by a steep decay, a plateau phase and a late power-law decay; Episode 4, corresponding to the optical SN emission due to the 56Ni decay. We focus on Episode 3 and we show that, from the thermal component observed during the steep decay of the prototype GRB 090618, the emission region has a typical dimension of ~1013 cm, which is inconsistent with the typical size of the emitting region of GRBs, e.g., ~1016 cm. We propose, therefore, that the X-ray afterglow emission originates from a spherically symmetric SN ejecta expanding at G ˜ 2 or, possibly, from the accretion onto the newly formed black hole, and we name these systems "binary driven hypernovae" (BdHNe). This interpretation is alternative to the traditional afterglow model based on the GRB synchrotron emission from a collimated jet outflow, expanding at ultra-relativistic Lorentz factor of G ~ 102-103 and originating from the collapse of a single object. We show then that the rest-frame energy band 0.3-10 keV X-ray luminosities of three selected BdHNe, GRB 060729, GRB 061121, and GRB 130427A, evidence a precisely constrained "nested" structure and satisfy precise scaling laws between the average prompt luminosity, < Liso>, and the luminosity at the end of the plateau, La, as functions of the time at the end of the plateau. All these features extend the applicability of the "cosmic candle" nature of Episode 3. The

  9. Relations between X-ray timing features and spectral parameters of Galactic black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Stiele, H.; Belloni, T. M.; Kalemci, E.; Motta, S.

    2013-03-01

    We present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX 339-4, H1743-322 and XTE J1650-500, as the Rossi X-ray Timing Explorer observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the High Energy X-ray Timing Experiment detector and select observations that show a certain type of quasi-periodic oscillations (QPOs; type-C). The spectral parameters are derived using the empirical convolution model SIMPL to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive correlation between photon index and centroid frequency of the QPOs and reveal an anticorrelation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the `sombrero' geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follows a general track, independent of individual outbursts.

  10. X-Ray Synchrotron-emitting Fe-rich Ejecta in Supernova Remnant RCW 86

    NASA Astrophysics Data System (ADS)

    Rho, Jeonghee; Dyer, Kristy K.; Borkowski, Kazimierz J.; Reynolds, Stephen P.

    2002-12-01

    Supernova remnants may exhibit both thermal and nonthermal X-ray emission. In a previous study with ASCA data, we found that the middle-aged supernova remnant RCW 86 showed evidence for both processes, and we predicted that observations with much higher spatial resolution would distinguish harder X-rays, which we proposed were primarily synchrotron emission, from softer, thermal X-rays. Here we describe Chandra observations that amply confirm our predictions. Striking differences in the morphology of X-rays below 1 keV and above 2 keV point to a different physical origin. Hard X-ray emission is correlated fairly well with the edges of regions of radio emission, suggesting that these are the locations of shock waves at which both short-lived X-ray-emitting electrons and longer lived radio-emitting electrons are accelerated. Soft X-rays are spatially well correlated with optical emission from nonradiative shocks, which are almost certainly portions of the outer blast wave. These soft X-rays are well fitted with simple thermal plane-shock models. Harder X-rays show Fe Kα emission and are well described with a similar soft thermal component, but a much stronger synchrotron continuum dominating above 2 keV, and a strong Fe Kα line. Quantitative analysis of this line and the surrounding continuum shows that it cannot be produced by thermal emission from a cosmic-abundance plasma; the ionization time is too short, as shown by both the low centroid energy (6.4 keV) and the absence of oxygen lines below 1 keV. Instead, a model of a plane shock in Fe-rich ejecta, with a synchrotron continuum, provides a natural explanation. This requires that reverse shocks in ejecta be accelerating electrons to energies of order 50 TeV. We show that maximum energies of this order can be produced by radiation-limited diffusive shock acceleration at the reverse shocks. In the Appendix, we demonstrate that an explanation of the continuum as being due to nonthermal bremsstrahlung is unlikely.

  11. An X-ray View of the Zoo of Compact Objects and Associated Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Safi-Harb, Samar

    2015-08-01

    Core-collapse explosions of massive stars leave behind some of the most exotic compact objects in the Universe. These include: rotation-powered pulsars like the Crab, powering pulsar wind nebulae (PWNe) observed across the electromagnetic spectrum; highly magnetized neutron stars ("magnetars") shining or bursting at high-energies; and X-ray emitting “Central Compact Objects” (CCOs) with intrinsic properties and emission mechanism that remain largely unknown. I will highlight this observed diversity of compact stellar remnants from an X-ray perspective, and address the connection between their properties and those of their hosting supernova remnants (SNRs). In particular I will highlight topics related to their formation and evolution, including: 1) which supernovae make magnetars and the shell-less PWNe?, 2) what can we learn from the apparent age discrepancy between SNRs and their associated pulsars? I will conclude with prospects for observations of SNRs with the upcoming ASTRO-H X-ray mission. The unprecedented spectral resolution on board of ASTRO-H’s micro-calorimeter will particularly open a new discovery window for supernova progenitors' science.

  12. A deep census of the X-ray binary populations in the SMC

    NASA Astrophysics Data System (ADS)

    Zezas, Andreas; Antoniou, Vallia; Hong, JaeSub; Wright, Nick; Drake, Jeremy J.; Haberl, Frank; SMC XVP Collaboration

    2016-04-01

    The analysis of the deep Chandra survey of the Small Magellanic Cloud (SMC) (a Chandra X-ray Visionary Program) yielded a wealth of discrete X-ray sources down to a limiting luminosity of a few times 1032 erg/s. The survey is designed to sample stellar populations of ages between ~10 up to ~100Myr, in order to study the evolution of the X-ray binary populations as a function of age. Based on the comparison of the detected X-ray sources with photometric catalogs of the SMC, we identify over 100 High Mass X-ray binaries (HMXBs) associated with the SMC, 21 of which exhibit pulsations. We measure the formation rate of HMXBs as a function of the age of their parent stellar populations, and we find that it shows a clear peak at ages of ~30-40Myr. In addition we measure the X-ray luminosity function of HMXBs which shows a clear break at a luminosity of ~5×1034 erg/s, indicative of the onset of the propeller effect. We discuss these results in the context of X-ray binary populations in environments of different ages and metallicities.

  13. Studying X-Ray Binaries with High Energy Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; West, Donald K. (Technical Monitor)

    2002-01-01

    The goal of this investigation is to further our understanding of the dynamics of secreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fetus. The main focus of this work has been a multi-year program of simultaneous millisecond X-ray timing and spectral observations carried out with the Rossi X-Ray Timing Explorer (RXTE) to perform the X-ray timing and one of the satellites Asca, BeppoSAX, or Chandra to perform X-ray spectral measurements. With the advent of Chandra, we have extended our work to incLude extragalactic X-ray binaries. We conducted a comprehensive study of the X-ray and radio behavior of the Black Hole Candidate (BHC) X-ray transient XTE J1550-564 using RXTE, Chandra, and the Australian Telescope Compact Array (ATCA). We showed that strong radio emission is associated with major X-ray outbursts involving an X-ray state transition, while a compact radio jet is seen in the low/hard X-ray state found in the outburst decay. Interesting, the total energy required to produce the compact jet may be a substantial fraction of the total accretion energy of the system in that state. We also performed a detailed study of the spectral and timing properties of the decay. In joint RXTE/BeppoSAX observations of the neutron-star X-ray binary Cyg X-2, we discovered a correlation between the timing properties (the frequency of the horizontal branch oscillations) and the properties of a soft, thermal component of the X-ray spectrum. d e showed that more detX- ray from accreting neutron stars. We have completed analysis of RXTE observations of the X-ray transient SAX J1750.8-2900 made after detection of X-ray bursts from the source with the BeppoSAX Wide-Field Camera. We discovered millisecond oscillations in both the persistent emission and in the X-ray bursts.

  14. Discovery of an X-Ray-emitting Contact Binary System 2MASS J11201034‑2201340

    NASA Astrophysics Data System (ADS)

    Hu, Chin-Ping; Yang, Ting-Chang; Chou, Yi; Liu, L.; Qian, S.-B.; Hui, C. Y.; Kong, Albert K. H.; Lin, L. C. C.; Tam, P. H. T.; Li, K. L.; Ngeow, Chow-Choong; Chen, W. P.; Ip, Wing-Huen

    2016-06-01

    We report the detection of orbital modulation, a model solution, and the X-ray properties of a newly discovered contact binary, Two Micron All Sky Survey (2MASS) J11201034‑2201340. We serendipitously found this X-ray point source outside the error ellipse when searching for possible X-ray counterparts of γ-ray millisecond pulsars among the unidentified objects detected by the Fermi Gamma-ray Space Telescope. The optical counterpart of the X-ray source (unrelated to the γ-ray source) was then identified using archival databases. The long-term Catalina Real-Time Transient Survey detected a precise signal with a period of P=0.28876208(56) days. A follow-up observation made by the Super Light Telescope of Lulin Observatory revealed the binary nature of the object. Utilizing archived photometric data of multi-band surveys, we construct the spectral energy distribution (SED), which is well fit by a K2V spectral template. The fitting result of the orbital profile using the Wilson–Devinney code suggests that 2MASS J11201034-2201340 is a short-period A-type contact binary and the more massive component has a cool spot. The X-ray emission was first noted in observations made by Swift, and then further confirmed and characterized by an XMM-Newton observation. The X-ray spectrum can be described by a power law or thermal Bremsstrahlung. Unfortunately, we could not observe significant X-ray orbital modulation. Finally, according to the SED, this system is estimated to be 690 pc from Earth with a calculated X-ray intensity of (0.7-1.5)× {10}30 erg s‑1, which is in the expected range of an X-ray emitting contact binary.

  15. MAXI/GSC detection of an X-ray flare-like activity probably from the high mass X-ray binary EXO 1722-363

    NASA Astrophysics Data System (ADS)

    Negoro, H.; Nakajima, M.; Serino, M.; Mihara, T.; Nakahira, S.; Ueno, S.; Tomida, H.; Ishikawa, M.; Sugawara, Y.; Sugizaki, M.; Iwakiri, W.; Shidatsu, M.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Isobe, N.; Sugita, S.; Yoshii, T.; Tachibana, Y.; Ono, Y.; Fujiwara, T.; Harita, S.; Muraki, Y.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Kitaoka, Y.; Tsunemi, H.; Shomura, R.; Tanaka, K.; Masumitsu, T.; Kawase, T.; Ueda, Y.; Kawamuro, T.; Hori, T.; Tanimoto, A.; Tsuboi, Y.; Nakamura, Y.; Sasaki, R.; Yamauchi, M.; Furuya, K.; Yamaoka, K.; Nakagawa, Y. E.

    2016-08-01

    At 05:06 UT on 2016 August 23, the MAXI/GSC nova-alert system triggered faint X-ray enhancement from the region positionally consistent with the super-giant high mass X-ray binary pulsar EXO 1722-363 (a.k.a., X 1722-36, IGR J17252-3616).

  16. THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

    SciTech Connect

    Zabalza, V.; Paredes, J. M.; Bosch-Ramon, V.

    2011-12-10

    Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

  17. Binary phase correlated X-ray intensity variations and flaring activity in the RS CVn binary HR 1099

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.; Vaidya, J.

    1988-01-01

    The monitor proportional counter and the imaging proportional counter of the Einstein Observatory were used to observe the X-ray variability of the RS CVn binary HR 1099. The X-ray intensity is found to vary with the 2.837-day period of the binary. An intense X-ray flare was noted on February 17, 1980. The present results are explained using a star spot model, and it is suggested that the flare heated plasma cools either mainly by radiation or equally by conduction and radiation.

  18. ON THE APPARENT LACK OF Be X-RAY BINARIES WITH BLACK HOLES

    SciTech Connect

    Belczynski, Krzysztof; Ziolkowski, Janusz E-mail: jz@camk.edu.p

    2009-12-20

    In our Galaxy there are 64 Be X-ray binaries known to date. Out of these, 42 host a neutron star (NS), and for the remainder the nature of the companion is unknown. None, so far, are known to host a black hole (BH). There seems to be no apparent mechanism that would prevent formation or detection of Be stars with BHs. This disparity is referred to as a missing Be-BH X-ray binary problem. We point out that current evolutionary scenarios that lead to the formation of Be X-ray binaries predict that the ratio of binaries with NSs to the ones with BHs is rather high, F{sub NStoBH} approx 10-50, with the more likely formation models providing the values at the high end. The ratio is a natural outcome of (1) the stellar initial mass function that produces more NSs than BHs and (2) common envelope evolution (i.e., a major mechanism involved in the formation of interacting binaries) that naturally selects progenitors of Be X-ray binaries with NSs (binaries with comparable mass components have more likely survival probabilities) over ones with BHs (which are much more likely to be common envelope mergers). A comparison of this ratio (i.e., F{sub NStoBH} approx 30) with the number of confirmed Be-NS X-ray binaries (42) indicates that the expected number of Be-BH X-ray binaries is of the order of only approx0-2. This is entirely consistent with the observed Galactic sample.

  19. Common envelope mechanisms: constraints from the X-ray luminosity function of high-mass X-ray binaries

    SciTech Connect

    Zuo, Zhao-Yu; Li, Xiang-Dong E-mail: lixd@nju.edu.cn

    2014-12-10

    We use the measured X-ray luminosity function (XLF) of high-mass X-ray binaries (HMXBs) in nearby star-forming galaxies to constrain the common envelope (CE) mechanisms, which play a key role in governing the binary evolution. We find that the XLF can be reproduced quite closely under both CE mechanisms usually adopted, i.e., the α{sub CE} formalism and the γ algorithm, with a reasonable range of parameters considered. Provided that the parameter combination is the same, the γ algorithm is likely to produce more HMXBs than the α{sub CE} formalism, by a factor of up to ∼10. In the framework of the α{sub CE} formalism, a high value of α{sub CE} is required to fit the observed XLF, though it does not significantly affect the global number of the HMXB populations. We present the detailed components of the HMXB populations under the γ algorithm and compare them with those in Zuo et al. and observations. We suggest the distinct observational properties, as well as period distributions of HMXBs, may provide further clues to discriminate between these two types of CE mechanisms.

  20. Spectral and timing nature of the symbiotic X-ray binary 4U 1954+319: The slowest rotating neutron star in an X-ray binary system

    SciTech Connect

    Enoto, Teruaki; Corbet, Robin H. D.; Sasano, Makoto; Yamada, Shin'ya; Tamagawa, Toru; Makishima, Kazuo; Pottschmidt, Katja; Marcu, Diana; Fuerst, Felix; Wilms, Jörn

    2014-05-10

    The symbiotic X-ray binary (SyXB) 4U 1954+319 is a rare system hosting a peculiar neutron star (NS) and an M-type optical companion. Its ∼5.4 hr NS spin period is the longest among all known accretion-powered pulsars and exhibited large (∼7%) fluctuations over 8 yr. A spin trend transition was detected with Swift/BAT around an X-ray brightening in 2012. The source was in quiescent and bright states before and after this outburst based on 60 ks Suzaku observations in 2011 and 2012. The observed continuum is well described by a Comptonized model with the addition of a narrow 6.4 keV Fe-Kα line during the outburst. Spectral similarities to slowly rotating pulsars in high-mass X-ray binaries, its high pulsed fraction (∼60%-80%), and the location in the Corbet diagram favor high B-field (≳ 10{sup 12} G) over a weak field as in low-mass X-ray binaries. The observed low X-ray luminosity (10{sup 33}-10{sup 35} erg s{sup –1}), probable wide orbit, and a slow stellar wind of this SyXB make quasi-spherical accretion in the subsonic settling regime a plausible model. Assuming a ∼10{sup 13} G NS, this scheme can explain the ∼5.4 hr equilibrium rotation without employing the magnetar-like field (∼10{sup 16} G) required in the disk accretion case. The timescales of multiple irregular flares (∼50 s) can also be attributed to the free-fall time from the Alfvén shell for a ∼10{sup 13} G field. A physical interpretation of SyXBs beyond the canonical binary classifications is discussed.

  1. Spectral and Timing Nature of the Symbiotic X-Ray Binary 4U 1954+319: The Slowest Rotating Neutron Star in AN X-Ray Binary System

    NASA Technical Reports Server (NTRS)

    Enoto, Teruaki; Sasano, Makoto; Yamada, Shin'Ya; Tamagawa, Toru; Makishima, Kazuo; Pottschmidt, Katja; Marcu, Diana; Corbet, Robin H. D.; Fuerst, Felix; Wilms, Jorn

    2014-01-01

    The symbiotic X-ray binary (SyXB) 4U 1954+319 is a rare system hosting a peculiar neutron star (NS) and an M-type optical companion. Its approx. 5.4 hr NS spin period is the longest among all known accretion-powered pulsars and exhibited large (is approx. 7%) fluctuations over 8 yr. A spin trend transition was detected with Swift/BAT around an X-ray brightening in 2012. The source was in quiescent and bright states before and after this outburst based on 60 ks Suzaku observations in 2011 and 2012. The observed continuum is well described by a Comptonized model with the addition of a narrow 6.4 keV Fe-K alpha line during the outburst. Spectral similarities to slowly rotating pulsars in high-mass X-ray binaries, its high pulsed fraction (approx. 60%-80%), and the location in the Corbet diagram favor high B-field (approx. greater than 10(exp12) G) over a weak field as in low-mass X-ray binaries. The observed low X-ray luminosity (10(exp33)-10(exp35) erg s(exp-1)), probable wide orbit, and a slow stellar wind of this SyXB make quasi-spherical accretion in the subsonic settling regime a plausible model. Assuming a approx. 10(exp13) G NS, this scheme can explain the approx. 5.4 hr equilibrium rotation without employing the magnetar-like field (approx. 10(exp16) G) required in the disk accretion case. The timescales of multiple irregular flares (approx. 50 s) can also be attributed to the free-fall time from the Alfv´en shell for a approx. 10(exp13) G field. A physical interpretation of SyXBs beyond the canonical binary classifications is discussed.

  2. Evidence For Quasi-Periodic X-ray Dips From An Ultraluminous X-ray Source: Implications for the Binary Motion

    NASA Technical Reports Server (NTRS)

    Pasham, Dheeraj R.; Strohmayer, Tod E.

    2013-01-01

    We report results from long-term (approx.1240 days) X-ray (0.3-8.0 keV) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Here we expand on earlier work by Strohmayer (2009) who used only a part of the present data set. Our primary results are: (1) the discovery of sharp, quasi-periodic, energy-independent dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6 +/- 4 days, the amplitude of which weakens during the second half of the light curve, and (3) spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data. We interpret the X-ray modulations within the context of binary motion in analogy to that seen in high-inclination accreting X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243 +/- 23 days, in contrast to the 115.5 day quasi-sinusoidal period previously reported by Strohmayer (2009). We discuss the overall X-ray modulation within the framework of accretion via Roche-lobe overflow of the donor star. In addition, if the X-ray modulation is caused by vertically structured obscuring material in the accretion disk, this would imply a high value for the inclination of the orbit. A comparison with estimates from accreting X-ray binaries suggests an inclination > or approx.70deg. We note that, in principle, a precessing accretion disk could also produce the observed X-ray modulations.

  3. Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reig, P.; Nersesian, A.; Zezas, A.; Gkouvelis, L.; Coe, M. J.

    2016-05-01

    Context. High-mass X-ray binaries are bright X-ray sources. The high-energy emission is caused by the accretion of matter from the massive companion onto a neutron star. The accreting material comes from either the strong stellar wind in binaries with supergiant companions or the cirscumstellar disk in Be/X-ray binaries. In either case, the Hα line stands out as the main source of information about the state of the accreting material. Aims: We present the results of our monitoring program to study the long-term variability of the Hα line in high-mass X-ray binaries. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. Methods: We fitted the Hα line with Gaussian profiles and obtained the line parameters and equivalent width. The peak separation in split profiles was used to determine the disk velocity law and estimate the disk radius. The relative intensity of the two peaks (V/R ratio) allowed us to investigate the distribution of gas particles in the disk. The equivalent width was used to characterise the degree of variability of the systems. We also studied the variability of the Hα line in correlation with the X-ray activity. Results: Our results can be summarised as follows: i) we find that Be/X-ray binaries with narrow orbits are more variable than systems with long orbital periods; ii) we show that a Keplerian distribution of gas particles provides a good description of the disks in Be/X-ray binaries, as it does in classical Be stars; iii) a decrease in the Hα equivalent width is generally observed after major X-ray outbursts; iv) we confirm that the Hα equivalent width correlates with disk radius; v) while systems with supergiant companions display multi-structured profiles, most of the Be/X-ray binaries show, at some epoch, double-peak asymmetric profiles, which indicates that density inhomogeneities is a common property in the disk of Be/X-ray binaries; vi) the

  4. X-ray emission from interacting wind massive binaries: A review of 15 years of progress

    NASA Astrophysics Data System (ADS)

    Rauw, Gregor; Nazé, Yaël

    2016-09-01

    Previous generations of X-ray observatories revealed a group of massive binaries that were relatively bright X-ray emitters. This was attributed to emission of shock-heated plasma in the wind-wind interaction zone located between the stars. With the advent of the current generation of X-ray observatories, the phenomenon could be studied in much more detail. In this review, we highlight the progress that has been achieved in our understanding of the phenomenon over the last 15 years, both on theoretical and observational grounds. All these studies have paved the way for future investigations using the next generation of X-ray satellites that will provide crucial information on the X-ray emission formed in the innermost part of the wind-wind interaction.

  5. Clumpy wind accretion in supergiant neutron star high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Bozzo, E.; Oskinova, L.; Feldmeier, A.; Falanga, M.

    2016-04-01

    The accretion of the stellar wind material by a compact object represents the main mechanism powering the X-ray emission in classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. In this work we present the first attempt to simulate the accretion process of a fast and dense massive star wind onto a neutron star, taking into account the effects of the centrifugal and magnetic inhibition of accretion ("gating") due to the spin and magnetic field of the compact object. We made use of a radiative hydrodynamical code to model the nonstationary radiatively driven wind of an O-B supergiant star and then place a neutron star characterized by a fixed magnetic field and spin period at a certain distance from the massive companion. Our calculations follow, as a function of time (on a total timescale of several hours), the transitions of the system through all different accretion regimes that are triggered by the intrinsic variations in the density and velocity of the nonstationary wind. The X-ray luminosity released by the system is computed at each time step by taking into account the relevant physical processes occurring in the different accretion regimes. Synthetic lightcurves are derived and qualitatively compared with those observed from classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. Although a number of simplifications are assumed in these calculations, we show that taking into account the effects of the centrifugal and magnetic inhibition of accretion significantly reduces the average X-ray luminosity expected for any neutron star wind-fed binary. The present model calculations suggest that long spin periods and stronger magnetic fields are favored in order to reproduce the peculiar behavior of supergiant fast X-ray transients in the X-ray domain.

  6. Clumpy wind accretion in supergiant neutron star high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Bozzo, E.; Oskinova, L.; Feldmeier, A.; Falanga, M.

    2016-05-01

    The accretion of the stellar wind material by a compact object represents the main mechanism powering the X-ray emission in classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. In this work we present the first attempt to simulate the accretion process of a fast and dense massive star wind onto a neutron star, taking into account the effects of the centrifugal and magnetic inhibition of accretion ("gating") due to the spin and magnetic field of the compact object. We made use of a radiative hydrodynamical code to model the nonstationary radiatively driven wind of an O-B supergiant star and then place a neutron star characterized by a fixed magnetic field and spin period at a certain distance from the massive companion. Our calculations follow, as a function of time (on a total timescale of several hours), the transitions of the system through all different accretion regimes that are triggered by the intrinsic variations in the density and velocity of the nonstationary wind. The X-ray luminosity released by the system is computed at each time step by taking into account the relevant physical processes occurring in the different accretion regimes. Synthetic lightcurves are derived and qualitatively compared with those observed from classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. Although a number of simplifications are assumed in these calculations, we show that taking into account the effects of the centrifugal and magnetic inhibition of accretion significantly reduces the average X-ray luminosity expected for any neutron star wind-fed binary. The present model calculations suggest that long spin periods and stronger magnetic fields are favored in order to reproduce the peculiar behavior of supergiant fast X-ray transients in the X-ray domain.

  7. SXP523 = Suzaku J0102-7204 = 2XMM J010247.4-720449, a Be/X-ray binary pulsar in the SMC

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Sturm, R.; Tsujimoto, M.; Wada, Q.; Ebisawa, K.; Miller, E.; Coe, M. J.; Klus, H.; Beardmore, A. P.

    2012-12-01

    After application of an attitude correction to the Suzaku observation of the supernova remnant 1E 0102.2-7219 described in ATel #4628, we derive an improved position for the X-ray pulsar Suzaku J0102-7204 of R.A. = 01:02:46.8, and Dec. = -72:04:56 (J2000, 1 sigma uncertainty of 20 arcsec). The new position is consistent with that of the Be/X-ray binary 2XMM J010247.4-720449 in the Small Magellanic Cloud seen by XMM-Newton, Swift and Chandra (ATel #3761) and most likely all detections are from the same source.

  8. Low-mass X-ray Binaries with RXTE

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Below are the publications which directly and indirectly evolved from this very successful program: 1) 'Search for millisecond periodicities in type I X-ray bursts of the Rapid Burster'; 2) 'High-Frequency QPOs in the 2000 Outburst of the Galactic Microquasar XTE J1550-564'; 3) 'Chandra and RXTE Spectroscopy of Galactic Microquasar XTE 51550-564 in Outburst'; 4) 'GX 339-4: back to life'; 5) 'Evidence for black hole spin in GX 339-4: XMM-Newton EPIC-PN and RXTE spectroscopy of the very high state'.

  9. Feedback from winds and supernovae in massive stellar clusters - II. X-ray emission

    NASA Astrophysics Data System (ADS)

    Rogers, H.; Pittard, J. M.

    2014-06-01

    The X-ray emission from a simulated massive stellar cluster is investigated. The emission is calculated from a 3D hydrodynamical model which incorporates the mechanical feedback from the stellar winds of three O stars embedded in a giant molecular cloud (GMC) clump containing 3240 M⊙ of molecular material within a 4 pc radius. A simple prescription for the evolution of the stars is used, with the first supernova (SN) explosion at t = 4.4 Myr. We find that the presence of the GMC clump causes short-lived attenuation effects on the X-ray emission of the cluster. However, once most of the material has been ablated away by the winds, the remaining dense clumps do not have a noticeable effect on the attenuation compared with the assumed interstellar medium (ISM) column. We determine the evolution of the cluster X-ray luminosity, LX, and spectra, and generate synthetic images. The intrinsic X-ray luminosity drops from nearly 1034 erg s-1 while the winds are `bottled up', to a near-constant value of 1.7 × 1032 erg s-1 between t = 1 and 4 Myr. LX reduces slightly during each star's red supergiant stage due to the depressurization of the hot gas. However, LX increases to ≈1034 erg s-1 during each star's Wolf-Rayet stage. The X-ray luminosity is enhanced by two to three orders of magnitude to ˜1037 erg s-1 for at least 4600 yr after each SN explosion, at which time the blast wave leaves the grid and the X-ray luminosity drops. The X-ray luminosity of our simulation is generally considerably fainter than predicted from spherically symmetric bubble models, due to the leakage of hot gas material through gaps in the outer shell. This process reduces the pressure within our simulation and thus the X-ray emission. However, the X-ray luminosities and temperatures which we obtain are comparable to similarly powerful massive young clusters.

  10. Unveiling optical and X-ray properties of the high mass X-ray binary XMMU J054134.7-682550

    NASA Astrophysics Data System (ADS)

    Lopes de Oliveira, R.; Placco, V. M.

    2014-10-01

    XMMU J054134.7-682550 is an X-ray source located in the Large Magellanic Cloud. Based on its X-ray properties, and from optical and near-infrared photometry, it was assumed to be a Be/X-ray binary. In this work we present the characterization of its optical counterpart from optical medium-resolution spectra acquired with the 3.6-m New Technology Telescope and the 4.1-m SOAR Telescope. Photospheric lines along with strong emission lines from the Hα, Hβ and several transitions of iron show that the optical counterpart is a Be star with a dense or large circumstellar disk. Thus, it is now conclusive that the system is indeed a Be/X-ray binary. Additionally, we present an ongoing program which aims to improve the characterization of the system from XMM-Newton, Swift/BAT and ASM/RXTE X-ray observations.

  11. GBS-discovered quiescent X-ray binaries: XMM eclipse duration and VLT spectra

    NASA Astrophysics Data System (ADS)

    Jonker, Peter

    2013-10-01

    We propose to use XMM to observe eclipsing probable quiescent low-mass X-ray binaries selected from the Galactic Bulge Survey. The XMM data are crucial to determine the eclipsing duration, one cannot do this as accurately from optical light curves as from X-ray light curves as the X-ray emission region is small compared to the mass donor star. Using the XMM eclipse duration and the VLT spectroscopy we can determine virtually model independent masses of the compact objects. Furthermore, we may select different mass ratio systems favoring low-mass black holes.

  12. Soft X-ray production by photon scattering in pulsating binary neutron star sources

    NASA Technical Reports Server (NTRS)

    Bussard, R. W.; Meszaros, P.; Alexander, S.

    1985-01-01

    A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

  13. Using Poisson statistics to analyze supernova remnant emission in the low counts X-ray regime

    NASA Astrophysics Data System (ADS)

    Roper, Quentin Jeffrey

    We utilize a Poisson likelihood in a maximum likelihood statistical analysis to analyze X-ray spectragraphic data. Specifically, we examine four extragalactic supernova remnants (SNR). IKT 5 (SNR 0047-73.5), IKT 25 (SNR 0104-72.3), and DEM S 128 (SNR 0103-72.4) which are designated as Type Ia in the literature due to their spectra and morphology. This is troublesome because of their asymmetry, a trait not usually associated with young Type Ia remnants. We present Chandra X-ray Observatory data on these three remnants, and perform a maximum likelihood analysis on their spectra. We find that the X-ray emission is dominated by interactions with the interstellar medium. In spite of this, we find a significant Fe overabundance in all three remnants. Through examination of radio, optical, and infrared data, we conclude that these three remnants are likely not "classical" Type Ia SNR, but may be examples of so-called "prompt" Type Ia SNR. We detect potential point sources that may be members of the progenitor systems of both DEM S 128 and IKT 5, which could suggest a new subclass of prompt Type Ia SNR, Fe-rich CC remnants. In addition, we examine IKT 18. This remnant is positionally coincident with the X-ray point source HD 5980. Due to an outburst in 1994, in which its brightness changed by 3 magnitudes (corrsponding to an increase in luminosity by a factor of 16) HD 5980 was classified as a luminous blue variable star. We examine this point source and the remnant IKT 18 in the X-ray, and find that its non-thermal photon index has decreased from 2002 to 2013, corresponding to a larger proportion of more energetic X-rays, which is unexpected.

  14. SELF-SHIELDING OF SOFT X-RAYS IN TYPE Ia SUPERNOVA PROGENITORS

    SciTech Connect

    Wheeler, J. Craig; Pooley, D.

    2013-01-10

    There are insufficient super-soft ({approx}0.1 keV) X-ray sources in either spiral or elliptical galaxies to account for the rate of explosion of Type Ia supernovae (SNe Ia) in either the single-degenerate or the double-degenerate scenarios. We quantify the amount of circumstellar matter that would be required to suppress the soft X-ray flux by yielding a column density in excess of 10{sup 23} cm{sup -2}. We summarize evidence that appropriate quantities of matter are extant in SNe Ia and in recurrent novae that may be supernova precursors. The obscuring matter is likely to have a large, but not complete, covering factor and to be substantially non-spherically symmetric. Assuming that much of the absorbed X-ray flux is re-radiated as blackbody radiation in the UV, we estimate that {approx}<100 sources might be detectable in the Galaxy Evolution Explorer All-sky Survey.

  15. Dosimetry of Microdistributed Dose-Enhancing Agents in X-ray Synchrotron Binary Therapy

    NASA Astrophysics Data System (ADS)

    Hugtenburg, Richard P.

    2010-07-01

    Monte Carlo based modelling of the dose distribution in the vicinity of concentrates of iodine (I) and gold (Au) binary radiotherapy agents has been performed for monochromatised synchrotron X-rays. While the KERMA approximation, which ignores electron transport, is often acceptable for kilovoltage X-ray dosimetry in X-ray binary therapy, the range of photoelectrons and Auger electrons may be significant when compared to the microdostributed structure of the binary compound in which case corrections to the approximation may be necessary. Dose is calculated using EGSnrc for microdistributions associated with X-ray radiation synovecotomy, where iodine is taken up in the synovial lining. Dose as a function of the volume of aggregation for an Au-based contrast agent such as Au nanoparticles, ranging in diameter from 5 micron to 100 micron, were calculated using EGSnrc and Penelope, showing that the dose varies slowly for 90 keV X-rays, where much of the dose delivered by short range photoelectrons while 80 keV X-rays, just below the K-edge of Au (80.729 keV) increases linearly with diameter. In general the dose varies slowly as a function of volume suggesting that only small corrections will be needed to account for effects due to the failure of electronic equilibrium.

  16. Dosimetry of Microdistributed Dose-Enhancing Agents in X-ray Synchrotron Binary Therapy

    SciTech Connect

    Hugtenburg, Richard P.

    2010-07-23

    Monte Carlo based modelling of the dose distribution in the vicinity of concentrates of iodine (I) and gold (Au) binary radiotherapy agents has been performed for monochromatised synchrotron X-rays. While the KERMA approximation, which ignores electron transport, is often acceptable for kilovoltage X-ray dosimetry in X-ray binary therapy, the range of photoelectrons and Auger electrons may be significant when compared to the microdostributed structure of the binary compound in which case corrections to the approximation may be necessary. Dose is calculated using EGSnrc for microdistributions associated with X-ray radiation synovecotomy, where iodine is taken up in the synovial lining. Dose as a function of the volume of aggregation for an Au-based contrast agent such as Au nanoparticles, ranging in diameter from 5 micron to 100 micron, were calculated using EGSnrc and Penelope, showing that the dose varies slowly for 90 keV X-rays, where much of the dose delivered by short range photoelectrons while 80 keV X-rays, just below the K-edge of Au (80.729 keV) increases linearly with diameter. In general the dose varies slowly as a function of volume suggesting that only small corrections will be needed to account for effects due to the failure of electronic equilibrium.

  17. The population of X-ray supernova remnants in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Maggi, P.; Haberl, F.; Kavanagh, P. J.; Sasaki, M.; Bozzetto, L. M.; Filipović, M. D.; Vasilopoulos, G.; Pietsch, W.; Points, S. D.; Chu, Y.-H.; Dickel, J.; Ehle, M.; Williams, R.; Greiner, J.

    2016-01-01

    Aims: We present a comprehensive X-ray study of the population of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). Using primarily XMM-Newton observations, we conduct a systematic spectral analysis of LMC SNRs to gain new insight into their evolution and the interplay with their host galaxy. Methods: We combined all the archival XMM-Newton observations of the LMC with those of our Very Large Programme LMC survey. We produced X-ray images and spectra of 51 SNRs, out of a list of 59 objects compiled from the literature and augmented with newly found objects. Using a careful modelling of the background, we consistently analysed all the X-ray spectra and measure temperatures, luminosities, and chemical compositions. The locations of SNRs are compared to the distributions of stars, cold gas, and warm gas in the LMC, and we investigated the connection between the SNRs and their local environment, characterised by various star formation histories. We tentatively typed all LMC SNRs, in order to constrain the ratio of core-collapse to type Ia SN rates in the LMC. We also compared the column densities derived from X-ray spectra to H i maps, thus probing the three-dimensional structure of the LMC. Results: This work provides the first homogeneous catalogue of the X-ray spectral properties of SNRs in the LMC. It offers a complete census of LMC remnants whose X-ray emission exhibits Fe K lines (13% of the sample), or reveals the contribution from hot supernova ejecta (39%), which both give clues to the progenitor types. The abundances of O, Ne, Mg, Si, and Fe in the hot phase of the LMC interstellar medium are found to be between 0.2 and 0.5 times the solar values with a lower abundance ratio [α/Fe] than in the Milky Way. The current ratio of core-collapse to type Ia SN rates in the LMC is constrained to NCC/NIa=1.35(-0.24+0.11), which is lower than in local SN surveys and galaxy clusters. Our comparison of the X-ray luminosity functions of SNRs in Local Group

  18. Soft X-Ray Spectroscopy of the Cygnus Loop Supernova Remnant

    NASA Astrophysics Data System (ADS)

    McEntaffer, R. L.; Cash, W.

    2008-06-01

    The Cygnus X-Ray Emission Spectroscopic Survey (CyXESS) sounding rocket payload was launched from White Sands Missile Range on 2006 November 20 and obtained a high-resolution spectrum of the Cygnus Loop supernova remnant in the soft X-ray. The novel X-ray spectrograph incorporated a wire-grid collimator feeding an array of gratings in the extreme off-plane mount that ultimately dispersed the spectrum onto gaseous electron multiplier (GEM) detectors. This instrument recorded 65 s of usable data between 43 and 49.5 Å in two prominent features. The first feature near 45 Å is dominated by the He-like triplet of O VII in second order with contributions from Mg X and Si IX-Si XII in first order, while the second feature near 47.5 Å is first-order S IX and S X. Fits to the spectra give an equilibrium plasma at log (T) = 6.2 (kTe = 0.14 keV) and near cosmic abundances. This is consistent with previous observations, which demonstrated that the soft X-ray emission from the Cygnus Loop is dominated by interactions between the initial blast wave and the walls of a precursor-formed cavity surrounding the Cygnus Loop and that this interaction can be described using equilibrium conditions.

  19. Thermal and Nonthermal X-Ray Emission from the Forward Shock in Tycho's Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Hwang, Una; Decourchelle, Anne; Holt, Stephen S.; Petre, Robert

    2002-12-01

    We present Chandra X-ray images of Tycho's supernova remnant that delineate its outer shock as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clumpy and have reached near the forward shock at numerous locations. Most of the X-ray spectra that we examine along the rim show evidence of line emission from Si and S ejecta, while the continuum is well represented by either a thermal or a nonthermal model. If the continuum is assumed to be thermal, the electron temperatures at the rim are all similar at about 2 keV, while the ionization ages are very low because of the overall weakness of the line emission. These electron temperatures are substantially below those expected for equilibration of the electron and ion temperatures, assuming shock velocities inferred from radio and X-ray expansion measurements; the electron-to-mean temperature ratios are <~0.1-0.2, indicating that collisionless heating of the electrons at the shock is modest. The nonthermal contribution to these spectra might be important, but cannot be strongly constrained by these data. It could account for as much as half of the flux in the 4-6 keV energy range, based on an extrapolation of the hard X-ray spectrum above 10 keV.

  20. VLBI Observations of the Shortest Orbital Period Black Hole X-Ray Binary

    NASA Astrophysics Data System (ADS)

    Paragi, Zsolt; Belloni, Tomaso M.; van der Horst, Alexander J.; Miller-Jones, James

    The X-ray transient MAXI J1659-152 was discovered by Swift/BAT and it was initially identified as a GRB. Soon its Galactic origin and binary nature were established. There exists a wealth of multi-wavelength monitoring data for this source, providing a great coverage of the full X-ray transition in this candidate black hole binary system. We obtained two epochs of EVN/e-VLBI and four epochs of VLBA data of MAXI J1659-152 which show evidence for some extended emission in the early phases but -against expectations- no major collimated ejecta during the accretion disk state transition. This might be related to the fact that, with a red dwarf donor star, MAXI J1659-152 is the shortest orbital period black hole X-ray binary system.

  1. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion

    NASA Technical Reports Server (NTRS)

    DilVrtilek, Saeqa; Mushotsky, Richard (Technical Monitor)

    2004-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. The second of two objects was observed on September of 2002. Data analysis for both observation has been completed: an investigation of the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure. A study of behavior of the emission features as a function of binary orbit shows modulated behavior in one of the systems. A paper on "High-resolution observations of low-mass X-ray binaries" is near completion. The paper includes observations with the Chandra HETG that are not yet completed.

  2. N157B: X-ray evidence for a Crab-like supernova remnant

    NASA Technical Reports Server (NTRS)

    Gotthelf, Eric V.; Wang, Q. Daniel

    1996-01-01

    The X-ray observation of the supernova remnant N 157B is described. The Rosat High Resolution Imager (HRI) X-ray emission from the remnant was decomposed into point-like sources. The spectra showed abundance-enhanced neon and magnesium lines, indicating that the remnant originated in a massive progenitor. The flat and featureless data from the Advanced Satellite for Cosmology and Astrophysics (ASCA) confirm the Crab-like nature of the remnant. By interpreting both the thermal spectral component and the shell as representing the remnant's outer shock, the age of the remnant was estimated to be 4 x 10(exp 3) yr and the energy release approximately 2 x 10(exp 50) erg.

  3. X-ray characteristics of the Lupus Loop and SN 1006 supernova remnants

    SciTech Connect

    Toor, A.

    1980-01-01

    The spatial extent of the Lupus Loop and spectra for the Lupus Loop and SN1006 supernova remnants have been determined with a rocket-borne payload. The Lupus Loop is an extended source of soft X-rays (approx. 300' diam) that shows a correlation between its brightest x-ray and radio-emission regions. Its spectrum is characterized by a temperature of 350 eV. Thus, the Lupus Loop appears similar to Vela X and Cygnus Loop, although much weaker. Emission from SN1006 is spatially unresolved and exhibits a harder spectrum than that of the Lupus Loop. All spectral data (0.2 to 10 keV) from our observation and previous observations are satisfactorily fit with a power law (index = 2.15). This spectral dependence suggests the possibility that a rotating neutron star is the underlying source of the radiated energy although such an interpretation appears inconsistent with the remnant's morphology.

  4. Swift X-Ray Upper Limits on Type Ia Supernova Environments

    NASA Technical Reports Server (NTRS)

    Russell, B. R.; Immler, S.

    2012-01-01

    We have considered 53 Type Ia supernovae (SNe Ia) observed by the Swift X-Ray Telescope. None of the SNe Ia are individually detected at any time or in stacked images. Using these data and assuming that the SNe Ia are a homogeneous class of objects, we have calculated upper limits to the X-ray luminosity (0.2-10 keV) and mass-loss rate of L(sub 0.2-10) < 1.7 X 10(exp 38) erg/s and M(dot) < l.l X 10(exp -6) solar M/ yr x (V(sub w))/(10 km/s), respectively. The results exclude massive or evolved stars as the companion objects in SN Ia progenitor systems, but allow the possibility of main sequence or small stars, along with double degenerate systems consisting of two white dwarfs, consistent with results obtained at other wavelengths (e.g., UV, radio) in other studies.

  5. Energy dependence of power-spectral noise in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Stiele, Holger; Yu, Wenfei

    2014-08-01

    Black hole and neutron star X-ray binaries show variability on time-scales ranging from milliseconds to years. In the last two decades a detailed phenomenological picture of short-term variability in low-mass X-ray binaries has emerged mainly based on RXTE observations that cover energies above 3 keV. This picture comprises periodic or quasi-periodic variability, seen as spikes or humps in power density spectra, that are superposed on broad noise components. The overall shape of the noise components as well as the occurrence of quasi-periodic oscillations is known to vary with the state of the X-ray binary. We are accomplishing a comprehensive study of archival XMM-Newton observations in timing or burst mode of more than ten black hole and more than thirty neutron star low-mass X-ray binaries to investigate the variability properties of these sources at softer energies where the thermal disk component starts to emerge.Here we present some results of the energy dependence of the noise component in power density spectra: a discussion of the energy dependence of the power spectral state that we found in the “plateau” state of GRS 1915+105 and the intermediate state of 4U 1630-47; the dependence of the break-frequency of the band-limited noise component as well as the quasi-periodic oscillations on the studied energy band in several X-ray binaries like GX 339-4 or Swift J1753.5-0127. We will discuss the implications of these findings for the picture of the accretion geometry in black hole X-ray binaries.

  6. The peculiar galactic center neutron star X-ray binary XMM J174457-2850.3

    SciTech Connect

    Degenaar, N.; Reynolds, M. T.; Miller, J. M.; Wijnands, R.; Altamirano, D.; Kennea, J.; Gehrels, N.; Haggard, D.; Ponti, G.

    2014-09-10

    The recent discovery of a millisecond radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially serve as a template to search for other X-ray binary/radio pulsar transitional objects. Here we demonstrate that the transient X-ray source XMM J174457-2850.3 near the Galactic center displays similar X-ray properties. We report on the detection of an energetic thermonuclear burst with an estimated duration of ≅2 hr and a radiated energy output of ≅ 5 × 10{sup 40} erg, which unambiguously demonstrates that the source harbors an accreting neutron star. It has a quiescent X-ray luminosity of L {sub X} ≅ 5 × 10{sup 32}(D/6.5 kpc){sup 2} erg s{sup –1} and exhibits occasional accretion outbursts during which it brightens to L {sub X} ≅ 10{sup 35}-10{sup 36}(D/6.5 kpc){sup 2} erg s{sup –1} for a few weeks (2-10 keV). However, the source often lingers in between outburst and quiescence at L {sub X} ≅ 10{sup 33}-10{sup 34}(D/6.5 kpc){sup 2} erg s{sup –1}. This peculiar X-ray flux behavior and its relatively hard X-ray spectrum, a power law with an index of Γ ≅ 1.4, could possibly be explained in terms of the interaction between the accretion flow and the magnetic field of the neutron star.

  7. LFN, QPO and fractal dimension of X-ray light curves from black hole binaries

    NASA Astrophysics Data System (ADS)

    Prosvetov, Art; Grebenev, Sergey

    The origin of the low frequency noise (LFN) and quasi-periodic oscillations (QPO) observed in X-ray flux of Galactic black hole binaries is still not recognized in spite of multiple studies and attempts to model this phenomenon. There are known correlations between the QPO frequency, X-ray power density, X-ray flux and spectral state of the system, but there is no model that can do these dependences understandable. For the low frequency (~1 Hz) QPO we still have no even an idea capable to explain their production and don't know even what part of an accretion disc is responsible for them. Here we attempted to measure the fractal dimension of X-ray light curves of several black hole X-ray binaries and to study its correlation with the frequency of quasi periodic oscillations observed in their X-ray light-curves. The fractal dimension is a measure of the space-filling capacity of the light curves' profile. To measure the fractal dimension we used R/S method, which is fast enough and has good reputation in financial analytic and materials sciences. We found that if no QPO were observed in X-ray flux from the particular source, the fractal dimension is equal to the unique value which is independent on the source, its luminosity or its spectral state. On the other hand if QPO were detected in the flux, the fractal dimension deviated from its usual value. Also, we found a clear correlation between the QPO frequency and the fractal dimension of the emission. The relationship between these two parameters is solid but nonlinear. We believe that the analysis of X-ray light curves of black hole binaries using the fractal dimension has a good scientific potential and may provide an addition information on the geometry of accretion flow and fundamental physical parameters of the system.

  8. A study of low mass x-ray binaries

    NASA Technical Reports Server (NTRS)

    Catura, Richard C.

    1994-01-01

    The entire effort under this contract during the period through January 1992 was devoted to a study of the cost and schedule required to put an upgraded Aries payload on the ASTRO-SPAS carrier provided by the German space agency, DARA. The ASTRO-SPAS is flown on the Space Shuttle, deployed by the crew for 5 to 7 days of free-flying observations and then recovered and returned to Earth. The spectrograph was to be provided by a collaboration involving the Lockheed Palo Alto Research Laboratory (LPARL), the Center for Astrophysics and Space Astronomy (CASA) at the U. of Colorado and the Mullard Space Science Laboratory (MSSL) in England. The payload for the ASTRO-SPAS mission included our own spectrograph and an instrument provided by Dr. Joachim Trumper of the Max Planck Institute (MPI) in Garching, Germany. A meeting was held in late July, 1991 with German scientists, DARA representatives and MBB, the ASTRO-SPAS spacecraft contractor. Sufficient information was exchanged to allow us to complete the study and the name LEXSA (Low Energy X-ray Spectrograph on ASTRO-SPAS) was given to our instrument and HERTA (High Energy x-Ray Telescope on ASTR0-SPAS) to the German instrument. The combination was called SPECTRO-SPAS. On October 1, 1991 CASA and LPARL submitted a cost and brief technical proposal to NASA on results of the study. The total cost over 4 fiscal years was 6.16 M dollars including CASA costs. NASA Headquarters was briefed on 3 October on details of the proposal. They found our costs reasonable, but indicated that the NASA FY '92 budget is extremely tight, they could not readily identify where the -S2.3M for LEXSA could be found and it was not clear that FY '93 would improve.

  9. A neutron-star-driven X-ray flash associated with supernova SN 2006aj.

    PubMed

    Mazzali, Paolo A; Deng, Jinsong; Nomoto, Ken'ichi; Sauer, Daniel N; Pian, Elena; Tominaga, Nozomu; Tanaka, Masaomi; Maeda, Keiichi; Filippenko, Alexei V

    2006-08-31

    Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosions resulting from the collapse of very massive stars ( approximately 40 M\\circ, where M\\circ is the mass of the Sun) stripped of their outer hydrogen and helium envelopes. A very massive progenitor, collapsing to a black hole, was thought to be a requirement for the launch of a GRB. Here we report the results of modelling the spectra and light curve of SN 2006aj (ref. 9), which demonstrate that the supernova had a much smaller explosion energy and ejected much less mass than the other GRB-supernovae, suggesting that it was produced by a star whose initial mass was only approximately 20 M\\circ. A star of this mass is expected to form a neutron star rather than a black hole when its core collapses. The smaller explosion energy of SN 2006aj is matched by the weakness and softness of GRB 060218 (an X-ray flash), and the weakness of the radio flux of the supernova. Our results indicate that the supernova-GRB connection extends to a much broader range of stellar masses than previously thought, possibly involving different physical mechanisms: a 'collapsar' (ref. 8) for the more massive stars collapsing to a black hole, and magnetic activity of the nascent neutron star for the less massive stars. PMID:16943833

  10. Effects of radiation pressure on the equipotential surfaces in X-ray binaries

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Mccluskey, G. E., Jr.; Gulden, S. L.

    1976-01-01

    Equipotential surfaces incorporating the effect of radiation pressure were computed for the X-ray binaries Cen X-3, Cyg X-1 = HDE 226868, Vela XR-1 = 3U 0900-40 = HD 77581, and 3U 1700-37 = HD 153919. The topology of the equipotential surfaces is significantly affected by radiation pressure. In particular, the so-called critical Roche (Jacobian) lobes, the traditional figure 8's, do not exist. The effects of these results on modeling X-ray binaries are discussed.

  11. X-ray Emission from Supernovae in Dense Circumstellar Matter Environments: a Search for Collisionless Shocks

    NASA Technical Reports Server (NTRS)

    Ofek, E. O.; Fox, D.; Cenko, Stephen B.; Sullivan, M; Gnat, O.; Frail, D. A.; Horesh, A.; Corsi, A.; Quimby, R. M.; Gehrels, N.; Kulkarni, S. R.; Gal-Yam, A.; Nugent, P. E.; Yaron, O.; Fillippenko, A. V; Kasliwal, M. M.; Bildsten, L.; Bloom, J. S.; Poznanski, D.; Arcavi, I.; Laher, R. R.; Levitan, D.; Sesar, B.; Surace, J..

    2013-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (the so-called shock breakout) in optically thick (Tau approx > 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and radiation-dominated shock in an optically thick wind must transform into a collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift/XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 Type IIn SNe, one Type Ibn SN, and eight hydrogen-poor superluminous SNe (SLSN-I such as SN 2005ap). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSM. However, the X-ray emission from SN 2006jc can also be explained as originating in an optically thin region. Thus, we propose that the optical light curve of SN 2010jl is powered by shock breakout in CSM. We suggest that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock-breakout model.We conclude that the light curves of some, but not all, SNe IIn/Ibn are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all of the SLSN-I events, our X-ray limits are not deep enough and were typically obtained too early (i.e., near the SN maximum light) for definitive conclusions about their nature. Late-time X-ray observations are required in order to further test whether these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakout in a wind profile. We argue that the timescale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above

  12. Studying X-Ray Binaries with High Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Kaaret, Philip

    2004-01-01

    The goal of this investigation is to further our understanding of the dynamics of accreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fields. The main focus of this work has been a multi-year program of millisecond X-ray timing and spectral observations of accreting compact objects. include imaging of X-ray jets from binaries and the study of extragalactic X-ray binaries. past year. Nine papers were accepted and/or published, as listed below. Seven of these are new since our previous annual report. With the advent of Chandra, we have extended our work to Significant progress was made over the The presentation of several talks and posters at astronomical meetings were supported by this grant. The PI was the lead organizer of "X-Ray Timing 2003: Rossi and Beyond", a major conference held in Cambridge, MA, in November, 2003. A t the conference we reviewed the accomplishments of the Rossi X-Ray Timing Explorer and developed the scientific motivation for a future X-ray timing mission. This conference was well attended and generated a significant amount of interest.

  13. Spectral variability in early-type binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Kallman, T. R.; Castor, J. I.; Olson, G. L.; Mccray, R.

    1984-01-01

    Theoretical models for the ionization of trace elements in a strong stellar wind by a compact binary X-ray source and for the resulting orbital phase dependence of the emergent soft X-ray spectra and the profiles of ultraviolet resonance lines are presented. Model results agree qualitatively with the X-ray and ultraviolet spectra of the system 4U 0900-40/HD 77581 and explain the suppression of the absorption profiles of the Si IV upsilon 1394 and C IV upsilon 1548 lines when the X-ray sources are in front of the star. The model predicts that the absorption profiles of the N V upsilon 1239 and O VI upsilon 1032 lines will be enhanced rather than suppresed during this orbital phase.Phase-dependent linear polarization in the resonance lines profiles is predicted. Future observations of these phase dependent effects in early-type binary X-ray systems may be used to investigate the dynamics of stellar winds and their interactions with the X-ray source.

  14. Spectral variability in early-type binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Mccray, R.; Kallman, T. R.; Castor, J. I.; Olson, G. L.

    1984-01-01

    Theoretical models for the ionization of trace elements in a strong stellar wind by a compact binary X-ray source and for the resulting orbital phase dependence of the emergent soft X-ray spectra and the profiles of ultraviolet resonance lines are presented. Model results agree qualitatively with the X-ray and ultraviolet spectra of the system 4U 0900-40/HD 77581 and explain the suppression of the absorption profiles of the Si IV upsilon 1394 and C IV upsilon 1548 lines when the X-ray sources is in front of the star. The model predicts that the absorption profiles of the N V upsilon 1239 and O VI upsilon 1032 lines will be enhanced rather than suppressed during this orbital phase. We predict phase-dependent linear polarization in the resonance lines profiles. Future observations of these phase dependent effects in early-type binary X-ray systems may be used to investigate the dynamics of stellar winds and their interactions with the X-ray source.

  15. Detection of an X-ray flare in the RS CVn binary Sigma Coronae Borealis

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.; Rao, A. R.; Riegler, G. R.

    1986-01-01

    The detection of an X-ray flare in the RS CVn binary Sigma Coronae Borealis with the Monitor Proportional Counter on the Einstein Observatory is described. During the 513 min of observation, an X-ray flare of 208 min duration was detected at a significance level of 26 sigma in the 1.19-10.16 keV band. The rise time of the flare is between 25 and 70 min and the decay time is greater than or equal to 34 min. The X-ray luminosity at the flare maximum is found to be 6 x 10 to the 30th erg/s and the total energy radiated in X-rays during the flare is 2 x 10 to the 34th erg. The energy spectrum in the flaring state is found to be harder (temperature T about 2.5 x 10 to the 7th K) compared to the one observed in the quiescent state (T about 6 x 10 to the 6th K). Applying the coronal loop model, the loop parameters are calculated and compared for the X-ray flares observed in the various RS CVn binaries and the sun. The significance of the differences in the observed and derived parameters of the X-ray flares is briefly discussed.

  16. Multi-wavelength study of X-ray binaries in the Magellanic clouds

    NASA Astrophysics Data System (ADS)

    Rajoelimanana, A. F.; Charles, P. A.

    We present the long-term temporal properties of X-rays binaries in the Magellanic Clouds using archival optical (from MACHO and OGLE) and X-ray (XMM-Newton) observations. The SMC has known to have an interesting over-abundant population of Be/X-ray binaries (BeX) as compared to our Galaxy. The majority of these SMC BeX display superorbital variations, many of them quasi-periodic on timescales of 200-3000 days, which are believed to be related to the formation and depletion of the Be star equatorial disk. The MACHO colour of these systems follow a clockwise loop-like structure in the colour-magnitude diagram. We also found a quasi-periodic variations in the prototype LMC supersoft source CAL 83. Its light curve shows dramatic brightness changes of ˜1 mag on timescales of ˜450 days. This supersoft source spends typically ˜200 days in the optical low state. Moreover, we have seen an anticorrelation between their X-ray and optical behaviour in which supersoft X-rays are detected during optical minima and very weak or completely off at optical maxima. Simple backbody fits to both high and low-state X-ray spectra reveals a decrease of blackbody temperature and luminosity when the optical counterpart brightens.

  17. Detection of X-ray emission from the PSR 1259-63/SS 2883 binary system

    NASA Technical Reports Server (NTRS)

    Cominsky, Lynn; Roberts, Mallory; Johnston, Simon

    1994-01-01

    Nonpulsed but variable X-ray emission has been detected from the binary system containing the radio pulsar PSR 1259-63 during two pointed ROSAT observations, taken 5 months apart. This 47.7 ms radio pulsar is in a highly eccentric (epsilon approximately 0.85) binary system with the 10-15 solar mass Be star SS 2883. It is the first radio pulsar found to be in a binary system with a massive main-sequence companion; it is also the most highly eccentric binary system known to contain a neutron star. The level of X-ray flux detected in the ROSAT observations has increased with orbital phase by a factor of at least 10 between 1992 February and 1993 February. The X-ray flux is significantly greater than expected from the Be star's corona and seems likely to originate either from low-level stellar wind accretion onto the neutron star or from the shock between the stellar wind and the relativistic pulsar wind. The system may be the progenitor of the more slowly rotating Be X-ray binary pulsar systems.

  18. THE CONNECTION BETWEEN X-RAY BINARIES AND STAR CLUSTERS IN NGC 4449

    SciTech Connect

    Rangelov, Blagoy; Chandar, Rupali; Prestwich, Andrea H.

    2011-11-10

    We present 23 candidate X-ray binaries with luminosities down to 1.8 Multiplication-Sign 10{sup 36} erg s{sup -1}, in the nearby starburst galaxy NGC 4449, from observations totaling 105 ks taken with the ACIS-S instrument on the Chandra Space Telescope. We determine count rates, luminosities, and colors for each source, and perform spectral fits for sources with sufficient counts. We also compile a new catalog of 129 compact star clusters in NGC 4449 from high-resolution, multi-band optical images taken with the Hubble Space Telescope, doubling the number of clusters known in this galaxy. The UBVI, H{alpha} luminosities of each cluster are compared with predictions from stellar evolution models to estimate their ages and masses. We find strong evidence for a population of very young massive, black hole binaries, which comprise nearly 50% of the detected X-ray binaries in NGC 4449. Approximately a third of these remain within their parent star clusters, which formed {tau} {approx}< 6-8 Myr ago, while others have likely been ejected from their parent clusters. We also find evidence for a population of somewhat older X-ray binaries, including both supergiant and Be-binaries, which appear to be associated with somewhat older {tau} Almost-Equal-To 100-400 Myr star clusters, and one X-ray binary in an ancient ({tau} Almost-Equal-To 10 Gyr) globular cluster. Our results suggest that detailed information on star clusters can significantly improve constraints on X-ray binary populations in star-forming galaxies.

  19. Single order X-ray diffraction with binary sinusoidal transmission grating

    NASA Astrophysics Data System (ADS)

    Cao, Leifeng

    2013-10-01

    All existing x-ray dispersive devices including crystals, multilayers and diffraction gratings generate spectra in multiple orders, whereas soft x-ray spectroscopy applications usually require only the first order spectrum. The other diffraction orders can overlap and contaminate the first order spectrum of interest. In this letter we describe how an axis-symmetrically-distributed sinusoidal-shaped aperture with binary transmittance values can be used to disperse x-rays and with a superior diffraction pattern where, along its symmetry axis, all higher-order diffractions can be effectively suppressed. Hence this sophisticated dispersive element generates pure soft x-ray spectra in the first diffraction order, free from interference from higher diffraction orders.

  20. Hydrodynamics of winds from irradiated companion stars in low-mass X-ray binaries

    NASA Technical Reports Server (NTRS)

    Tavani, Marco; London, Richard

    1993-01-01

    We study the hydrodynamics of evaporative winds driven by X-rays and/or soft gamma-rays irradiating the outer layers of companion stars in low-mass X-ray binaries (LMXBs). We consider several irradiating fluxes and spectra for LMXBs with white dwarf and main-sequence companion stars. The thermal structure of the base of the coronal region, the position of the sonic point, and the value of the mass-loss rate are calculated in the case of spherical geometry. We consider photospheric and coronal heating from both X-ray photoionization and Compton scattering of X-rays and soft gamma-rays with energy about 1 MeV possibly irradiating the companion star in LMXBs. Evaporative winds may play a relevant role for the evolution of a special class of radiation-driven LMXBs, and this study is a step toward a quantitative understanding of the mechanism driving LMXB evolution.

  1. Recurrent X-ray Emission Variations of Eta Carinae and the Binary Hypothesis

    NASA Technical Reports Server (NTRS)

    Ishibashi, K.; Corcoran, M. F.; Davidson, K.; Swank, J. H.; Petre, R.; Drake, S. A.; Damineki, A.; White, S.

    1998-01-01

    Recent studies suggest that, the super-massive star eta Carinae may have a massive stellar companion (Damineli, Conti, and Lopes 1997), although the dense ejecta surrounding the star make this claim hard to test using conventional methods. Settling this question is critical for determining the current evolutionary state and future evolution of the star. We address this problem by an unconventional method: If eta Carinae is a binary, X-ray emission should be produced in shock waves generated by wind-wind collisions in the region between eta Carinae and its companion. Detailed X-ray monitoring of eta Carinae for more that) 2 years shows that the observed emission generally resembles colliding-wind X-ray emission, but with some significant discrepancies. Furthermore, periodic X-ray "flaring" may provide an additional clue to determine the presence of a companion star and for atmospheric pulsation in eta Carinae.

  2. Multiwavelength study of the transient X-ray binary IGR J01583+6713

    NASA Astrophysics Data System (ADS)

    Kaur, Ramanpreet; Paul, Biswajit; Kumar, Brijesh; Sagar, Ram

    2008-06-01

    We have investigated multiband optical photometric variability and stability of the Hα line profile of the transient X-ray binary IGR J01583+6713. We set an upper limit of 0.05 mag on photometric variations in the V band over a time-scale of three months. The Hα line is found to consist of non-Gaussian profile and quite stable for a duration of two months. We have identified the spectral type of the companion star to be B2 IVe while the distance to the source is estimated to be ~4.0 kpc. Along with the optical observations, we have also carried out analysis of X-ray data from three short observations of the source, two with the Swift-XRT and one with the RXTE-PCA. We have detected a variation in the absorption column density, from a value of 22.0 × 1022 cm-2 immediately after the outburst down to 2.6 × 1022 cm-2 four months afterwards. In the quiescent state, the X-ray absorption is consistent with the optical reddening measurement of E(B - V) = 1.46 mag. From one of the Swift observations, during which the X-ray intensity was higher, we have a possible pulse detection with a period of 469.2 s. For a Be X-ray binary, this indicates an orbital period in the range of 216-561 d for this binary system.

  3. High Time Resolution Studies of Binary X-Ray Pulsars

    NASA Astrophysics Data System (ADS)

    Cominsky, Lynn R.

    1996-05-01

    The work for this project was substantially more than anticipated, and involved recreating an analysis system for all the HEAO A-1 scanning data which had been converted to the ELE format. As a result of this work, a complete software analysis package was first created at Sonoma State University using Fortran, that can extract the data for any given X-ray source, and produce light curves from the scanning data. A second complete software analysis package was also created, this time in IDL, which can also display all the data in a timely manner, allowing data screening without the generation of hardcopy plots. The creation of the software systems was not the original goal of the project; rather this was a necessary result when the NRL computers became inoperable due to old age and could not be used to support the project, as originally planned. There were 6 sources originally proposed for analysis: SMC X-1, A0538-66, LMC X-1, LMC X-3, (these 3 sources are all located in the Large Magellanic Cloud region), 4UO115+63 and 4U1626-67. Results on these sources are summarized.

  4. Late-Time X-Ray, UV, and Optical Monitoring of Supernova 1979C

    NASA Astrophysics Data System (ADS)

    Immler, Stefan; Fesen, Robert A.; Van Dyk, Schuyler D.; Weiler, Kurt W.; Petre, Robert; Lewin, Walter H. G.; Pooley, David; Pietsch, Wolfgang; Aschenbach, Bernd; Hammell, Molly C.; Rudie, Gwen C.

    2005-10-01

    We present results from observations of supernova (SN) 1979C with the Newton X-Ray Multi-Mirror (XMM-Newton) mission in X-rays and in UV, archival X-ray, and Hubble Space Telescope (HST) data, and follow-up ground-based optical imaging. The XMM-Newton MOS spectrum shows the best-fit two-temperature thermal plasma emission characteristics of both the forward (kThigh=4.1+76-2.4 keV) and reverse shock (kTlow=0.79+0.24-0.17 keV) with no intrinsic absorption. The long-term X-ray light curve, constructed from all X-ray data available, reveals that SN 1979C is still radiating at a flux level similar to that detected by ROSAT in 1995, showing no sign of a decline over the last 6 years, some 16-23 yr after its outburst. The high inferred X-ray luminosity (L0.3-2=8×1038 ergs s-1) is caused by the interaction of the SN shock with dense circumstellar matter, likely deposited by a strong stellar wind from the progenitor with a high mass-loss rate of M˙~1.5×10-4 Msolar yr-1 (vw/10 km s-1). The X-ray data support a strongly decelerated shock and show a mass-loss rate history that is consistent with a constant progenitor mass-loss rate and wind velocity over the past >~16,000 yr in the stellar evolution of the progenitor. We find a best-fit circumstellar medium (CSM) density profile of ρCSM~r-s with index s<~1.7 and high CSM densities (>~104 cm-3) out to large radii from the site of the explosion (r>~4×1017 cm). Using XMM-Newton Optical Monitor data, we further detect a pointlike optical/UV source consistent with the position of SN 1979C, with B-, U-, and UVW1-band luminosities of 5, 7, and 9×1036 ergs s-1, respectively. The young stellar cluster in the vicinity of the SN, as imaged by the HST and follow-up ground-based optical imaging, can only provide a fraction of the total observed flux, so that a significant contribution to the output likely arises from the strong interaction of SN 1979C with dense CSM.

  5. X-Ray Emission from Supernovae in Dense Circumstellar Matter Environments: A Search for Collisionless Shock

    NASA Technical Reports Server (NTRS)

    Ofek, E.O; Fox, D.; Cenko, B.; Sullivan, M.; Gnat, O.; Frail A.; Horesh, A.; Corsi, A; Quimby, R. M.; Gehrels, N.; Kulkarni, S. R.; Gal-Yam, A.; Nugent, P. E.; Yaron, O.; Filippenko, A. V.; Kasliwal, M. M.; Bildsten, L.; Bloom, J. S.; Poznanski, D; Arcavi, L.; Laher, R. R.; Levitan, D.; Sesar, B.; Surace, J.

    2012-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (so-called shock breakout) in optically thick (tau approx > 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and -dominated shock in an optically thick wind must transform into 8. collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift-XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 type-IIn SNe, one type-Ibn SN and eiht hydrogen-poor super-luminous SNe (SLSN-I; SN 2005ap like). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSl\\l. Therefore, we suggest that their optical light curves are powered by shock breakout in CSM. We show that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock breakout model. We conclude that the light curves of some, but not all, type-IIn/Ibn SNe are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all the SLSN-I events, our X-ray limits are not deep enough and were typically obtained at too early times (i.e., near the SN maximum light) to conclude about their nature. Late time X-ray observations are required in order to further test if these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakOut in a wind profile. We argue that the time scale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above the shock region. The optical light curves of SNe, for which the X-ray emission peaks at late times, are likely powered by the

  6. Double core evolution and X-ray binaries

    NASA Technical Reports Server (NTRS)

    Taam, R. E.

    1979-01-01

    The evolution of a 16-solar mass star and a 1-solar mass neutron star is followed through the common-envelope binary phase. It is found that the encounter of the neutron star with a yellow giant leads to coalescence of the two cores, while encounter with a red giant leads to hydrodynamic expansion and probable ejection of the common envelope. Within the context of the two rotation laws (1) uniform rotation (investigated in the present study), and (2) uniform specific angular momentum (considered in an earlier study), the results are independent of the choice for the angular-momentum distribution in the common envelope. Implications of the results for the binary pulsar phase are discussed.

  7. Period Derivative of the M15 X-Ray Binary AC211/X2127+119

    NASA Technical Reports Server (NTRS)

    Homer, L.; Charles, P. A.

    1998-01-01

    We have combined Rossi X-ray Timing Explorer observations of X2127+119, the low-mass X-ray binary in the globular cluster M15, with archival X-ray lightcurves to study the stability of the 17.1 hr orbital period. We find that the data cannot be fit by the Ilovaisky ephemeris, and requires either a 7.sigma change to the period or a period derivative P prime/P approximately 9 x 10(exp -7)/yr. Given its remarkably low L(sub X)/L(sub opt) such a P prime lends support to models that require super-Eddington mass transfer in a q approximately 1 binary.

  8. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion

    NASA Technical Reports Server (NTRS)

    Vrtilek, Saeqa Dil; Mushotzky, Richard F. (Technical Monitor)

    2002-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. The second of two objects was not observed until September of 2002. Data analysis for the new observation is underway. over the next year we will: investigate the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure; study the behavior of emission features as a function of binary orbit; and test and improve models of X-ray line emission developed by us over the past decade. We will gain insight on both the geometry of the accretion flow and on the evolutionary history of LMXBs.

  9. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion. Revised

    NASA Technical Reports Server (NTRS)

    DilVrtilek, Saeqa; Mushotzky, Richard (Technical Monitor)

    2001-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. observation of one of the two objects has taken place and the data were received in late November. The second object is yet to be observed. Over the next year we will: investigate the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure; study the behavior of emission features as a function of binary orbit; and test and improve models of X-ray line emission developed by us over the past decade. We will gain insight on both the geometry of the accretion flow and on the evolutionary history of LMXBs.

  10. All the X-ray binaries in the Universe: X-ray Emission from Normal and Starburst Galaxies Near and Far

    NASA Astrophysics Data System (ADS)

    Hornschemeier, Ann; Basu-Zych, Antara; Lehmer, Bret

    2015-08-01

    There has recently been quite a bit of excitement on the role of X-ray emission from galaxies in early heating of the IGM, demonstrating that understanding of X-ray emission from normal and starburst galaxies may have significant impact on structure formation in the Universe. The X-ray output from X-ray binaries and hot gas are both important and may rival the ionizing output of AGN at z>5, particularly for Hydrogen reionization. Here we present our research on constraining the X-ray SED of galaxies across cosmic time via several complementary approaches. In the very local universe (d <~ 30 Mpc including the Local Group) we are using NuSTAR to understand the accretion states and total output of black hole and neutron star binaries using the important lever arm of 0.5-30 keV emission. At intermediate distances (10-100 Mpc), we are comparing the X-ray output of galaxies with star formation histories and population synthesis model predictions using both Chandra and XMM data. In the slightly more distant universe (z~0.1-0.2) we can find rare analogs to primordial starbursts via wide-field optical/UV surveys that may be studied with Chandra. We will finish with a discussion of starburst galaxies emitting X-rays at z>4, which thanks to the extremely deep Chandra Deep Field-South 7 Ms survey, are better constrained than ever before. We discuss survey strategy and how the various pieces of the puzzle fit together regarding the X-ray output of galaxies and their X-ray binary populations over cosmic time. We discuss implications for next-generation missions and instruments, including those with wide-field survey capabilities and high throughput, especially the Athena mission.

  11. Observations of the supernova remnant G54.1+0.3: X-ray spectrum and evidence for an X-ray jet

    NASA Astrophysics Data System (ADS)

    Lu, F. J.; Aschenbach, B.; Song, L. M.

    2001-05-01

    We present analyses of the ROSAT PSPC and the ASCA SIS and GIS observations of the Crab-like supernova remnant (SNR) G54.1+0.3. The spectrum is best fitted by a power law model with a photon index of -1.9+0.2-0.2, absorbed energy flux of 6.8 10-12 erg cm-2 s-1 in the 0.7-10 keV band, and a column density of 17.9+2.8-2.5 1021 cm-2. The high absorption column density indicates a distance close to the radius of the galaxy. The 0.7-10.0 keV X-ray luminosity of G54.1+0.3 is 1.4 1035d102 erg s-1, where d10 is the distance in 10 kpc. With an image restoration method, we have deconvolved the X-ray image of the remnant. There is evidence for an X-ray jet pointing to the north-east with a length of about 40arcsec measured from the center of the nebula. Its X-ray luminosity in the 0.1-2.4 keV range is about 2.1 1034d102 erg s-1. The X-ray jet is consistent with the radio extension of G54.1+0.3 to the north-east in both direction and position.

  12. AN X-RAY INVESTIGATION OF THREE SUPERNOVA REMNANTS IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Klimek, Matthew D.; Points, S. D.; Smith, R. C.; Shelton, R. L.; Williams, R. E-mail: spoints@ctio.noao.ed E-mail: rls@physast.uga.ed

    2010-12-20

    We have investigated three supernova remnants (SNRs) in the LMC using multi-wavelength data. These SNRs are generally fainter than the known sample (see Section 4) and may represent a previously missed population. One of our SNRs is the second LMC remnant analyzed which is larger than any Galactic remnant for which a definite size has been established. The analysis of such a large remnant contributes to the understanding of the population of highly evolved SNRs. We have obtained X-ray images and spectra of three of these recently identified SNRs using the XMM-Newton observatory. These data, in conjunction with pre-existing optical emission-line images and spectra, were used to determine the physical conditions of the optical- and X-ray-emitting gas in the SNRs. We have compared the morphologies of the SNRs in the different wavebands. The physical properties of the warm ionized shell were determined from the H{alpha} surface brightness and the SNR expansion velocity. The X-ray spectra were fit with a thermal plasma model and the physical conditions of the hot gas were derived from the model fits. Finally, we have compared our observations with simulations of SNR evolution.

  13. Feature-tailored spectroscopic analysis of the supernova remnant Puppis A in X-rays

    NASA Astrophysics Data System (ADS)

    Luna, G. J. M.; Smith, M. J. S.; Dubner, G.; Giacani, E.; Castelletti, G.

    2016-05-01

    We introduce a distinct method for performing spatially resolved spectral analysis of astronomical sources with highly structured X-ray emission. The method measures the surface brightness of neighboring pixels to adaptively size and shape each region, thus the spectra from the bright and faint filamentary structures evident in the broadband images can be extracted. As a test case, we present the spectral analysis of the complete X-ray emitting plasma in the supernova remnant Puppis A observed with XMM-Newton and Chandra. Given the angular size of Puppis A, many pointings with different observational configurations have to be combined, presenting a challenge to any method of spatially resolved spectroscopy. From the fit of a plane-parallel shocked plasma model we find that temperature, absorption column, ionization time scale, emission measure, and elemental abundances of O, Ne, Mg, Si, S, and Fe, are smoothly distributed in the remnant. Some regions with overabundances of O, Ne, and Mg previously characterized as ejecta material, were automatically selected by our method, proving the excellent response of the technique. This method is an advantageous tool for the exploitation of archival X-ray data.

  14. A CHANDRA X-RAY SURVEY OF EJECTA IN THE CASSIOPEIA A SUPERNOVA REMNANT

    SciTech Connect

    Hwang, Una; Laming, J. Martin E-mail: laming@nrl.navy.mil

    2012-02-20

    We present a survey of the X-ray-emitting ejecta in the Cassiopeia A supernova remnant (SNR) based on an extensive analysis of over 6000 spectral regions extracted on 2.''5-10'' angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age, and the implied mass coordinates, are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks following reverse shock interaction with ejecta inhomogeneities. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray-emitting ejecta and also show the distribution of the mass of various elements over the remnant. An upper limit to the total shocked Fe mass visible in X-rays appears to be roughly 0.13 M{sub Sun }, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si burning and that possibly associated with {alpha}-rich freezeout, with a mass ratio of approximately 2:1. Essentially all of the observed Fe (both components) lies well outside the central regions of the SNR, possibly having been ejected by hydrodynamic instabilities during the explosion. We discuss this and its implications for the neutron star kick.

  15. Kepler's Supernova Remnant: A View from Chandra X-Ray Observatory

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    [figure removed for brevity, see original site] Figure 1

    Each top panel in the composite above shows the entire remnant. Each color in the composite represents a different region of the electromagnetic spectrum, from X-rays to infrared light. The X-ray and infrared data cannot be seen with the human eye. Astronomers have color-coded those data so they can be seen in these images.

    The bottom panels are close-up views of the remnant. In the bottom, center image, Hubble sees fine details in the brightest, densest areas of gas. The region seen in these images is outlined in the top, center panel.

    The images indicate that the bubble of gas that makes up the supernova remnant appears different in various types of light. Chandra reveals the hottest gas [colored blue and colored green], which radiates in X-rays. The blue color represents the higher-energy gas; the green, the lower-energy gas. Hubble shows the brightest, densest gas [colored yellow], which appears in visible light. Spitzer unveils heated dust [colored red], which radiates in infrared light.

  16. Thermal and Nonthermal X-ray Emission from the Forward Shock in Tycho's Supernova Remnant

    NASA Technical Reports Server (NTRS)

    Hwang, Una; Decourchelle, Anne; Holt, Stephen S.; Petre, Robert; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present Chandra CCD images of Tycho's supernova remnant that delineate its outer shock, seen as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clumpy, and have reached the forward shock at numerous locations. Most of the X-ray spectra that we examine along the rim show line emission from Si and S, which in some cases must come from ejecta; the continuum is well represented by either thermal or nonthermal models. In the case that the continuum is assumed to be thermal, the temperatures at the rim are all similar at about 2 keV, and the ionization ages are very low because of the overall weakness of the line emission. Assuming shock velocities inferred from radio and X-ray expansion measurements, these temperatures are substantially below those expected for equilibration of the electron and ion temperatures; electron to mean temperature ratios of approximately less than 0.1 - 0.2 indicate at most modest collisionless heating of the electrons at the shock. The nonthermal contribution to these spectra may be important, however, and may account for as many as half of the counts in the 4-6 keV energy range, based on an extrapolation of the hard X-ray spectrum above 10 keV.

  17. A1540-53, an eclipsing X-ray binary pulsator

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Saba, J. R.; Serlemitsos, P. J.

    1977-01-01

    An eclipsing X-ray binary pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from eclipse suggest an early type, giant or supergiant, primary star.

  18. Relativistic Astrophysics in Black Hole and Low-Mass Neutron Star X-ray Binaries

    NASA Technical Reports Server (NTRS)

    2000-01-01

    During the five-year period, our study of "Relativistic Astrophysics in Black Hole and Low-Mass Neutron Star X-ray Binaries" has been focused on the following aspects: observations, data analysis, Monte-Carlo simulations, numerical calculations, and theoretical modeling. Most of the results of our study have been published in refereed journals and conference presentations.

  19. Outburst from low-mass X-ray binary GRS 1747-312 in Terzan 6

    NASA Astrophysics Data System (ADS)

    Bahramian, A.; Heinke, C. O.; Sivakoff, G. R.; Kennea, J. A.; Wijnands, R.; Altamirano, D.

    2016-05-01

    GRS 1747-312 is an eclipsing transient low-mass X-ray binary in the core of the globular cluster Terzan 6. This source shows regular outbursts ~ every 6 months and, due to its eclipsing behaviour, has an accurately-constrained orbital period (12.36 hrs, in't Zand et al. 2003, A & A, 406, 233).

  20. Supernova Remnants Interacting with Molecular Clouds: X-Ray and Gamma-Ray Signatures

    NASA Astrophysics Data System (ADS)

    Slane, Patrick; Bykov, Andrei; Ellison, Donald C.; Dubner, Gloria; Castro, Daniel

    2015-05-01

    The giant molecular clouds (MCs) found in the Milky Way and similar galaxies play a crucial role in the evolution of these systems. The supernova explosions that mark the death of massive stars in these regions often lead to interactions between the supernova remnants (SNRs) and the clouds. These interactions have a profound effect on our understanding of SNRs. Shocks in SNRs should be capable of accelerating particles to cosmic ray (CR) energies with efficiencies high enough to power Galactic CRs. X-ray and γ-ray studies have established the presence of relativistic electrons and protons in some SNRs and provided strong evidence for diffusive shock acceleration as the primary acceleration mechanism, including strongly amplified magnetic fields, temperature and ionization effects on the shock-heated plasmas, and modifications to the dynamical evolution of some systems. Because protons dominate the overall energetics of the CRs, it is crucial to understand this hadronic component even though electrons are much more efficient radiators and it can be difficult to identify the hadronic component. However, near MCs the densities are sufficiently high to allow the γ-ray emission to be dominated by protons. Thus, these interaction sites provide some of our best opportunities to constrain the overall energetics of these particle accelerators. Here we summarize some key properties of interactions between SNRs and MCs, with an emphasis on recent X-ray and γ-ray studies that are providing important constraints on our understanding of cosmic rays in our Galaxy.

  1. High-mass X-ray binaries in the Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Sturm, R.

    2016-02-01

    Aims: The last comprehensive catalogue of high-mass X-ray binaries in the Small Magellanic Cloud (SMC) was published about ten years ago. Since then new such systems were discovered, mainly by X-ray observations with Chandra and XMM-Newton. For the majority of the proposed HMXBs in the SMC no X-ray pulsations were discovered as yet, and unless other properties of the X-ray source and/or the optical counterpart confirm their HMXB nature, they remain only candidate HMXBs. Methods: From a literature search we collected a catalogue of 148 confirmed and candidate HMXBs in the SMC and investigated their properties to shed light on their real nature. Based on the sample of well-established HMXBs (the pulsars), we investigated which observed properties are most appropriate for a reliable classification. We defined different levels of confidence for a genuine HMXB based on spectral and temporal characteristics of the X-ray sources and colour-magnitude diagrams from the optical to the infrared of their likely counterparts. We also took the uncertainty in the X-ray position into account. Results: We identify 27 objects that probably are misidentified because they lack an infrared excess of the proposed counterpart. They were mainly X-ray sources with a large positional uncertainty. This is supported by additional information obtained from more recent observations. Our catalogue comprises 121 relatively high-confidence HMXBs (the vast majority with Be companion stars). About half of the objects show X-ray pulsations, while for the rest no pulsations are known as yet. A comparison of the two subsamples suggests that long pulse periods in excess of a few 100 s are expected for the "non-pulsars", which are most likely undetected because of aperiodic variability on similar timescales and insufficiently long X-ray observations. The highest X-ray variability together with the lowest observed minimum fluxes for short-period pulsars indicate that in addition to the eccentricity of the

  2. Chemical abundances of the secondary star in the neutron star X-ray binary Cygnus X-2

    NASA Astrophysics Data System (ADS)

    Suárez-Andrés, L.; González Hernández, J. I.; Israelian, G.; Casares, J.; Rebolo, R.

    2015-03-01

    We present Utrecht Echelle Spectrograph@William Herschel Telescope high-resolution spectra of the low-mass X-ray binary (LMXB) Cygnus X-2. We have derived the stellar parameters of the secondary star using χ2 minimization procedure, and taking into account any possible veiling from the accretion disc. We determine a metallicity higher than solar ([Fe/H] = 0.27 ± 0.19), as seen also in the neutron star X-ray binary Centaurus X-4. The high quality of the secondary's spectrum allow us to determine the chemical abundances of O, Mg, Si, Ca, S, Ti, Fe, and Ni. We found that some α-elements (Mg, Si, S, Ti) are enhanced, consistent with a scenario of contamination of the secondary star during the supernova event. Surprisingly oxygen appears to be underabundant, whereas enhanced abundances of Fe and Ni are measured. Assuming that these abundances come from matter that has been processed in the SN and then captured by the secondary star, we explore different SN explosion scenarios with diverse geometries. A non-spherically symmetric SN explosion, with a low mass cut, seems to reproduce better the observed abundance pattern of the secondary star compared to the spherical case.

  3. On the lack of X-ray bright Type IIP supernovae

    NASA Astrophysics Data System (ADS)

    Dwarkadas, V. V.

    2014-05-01

    Type IIP supernovae (SNe) are expected to arise from red supergiant stars (RSGs). These stars have observed mass-loss rates that span more than two orders of magnitude, from less than 10^{-6} M_{⊙} yr-1 to almost 10^{-4} M_{⊙} yr-1. Thermal bremsstrahlung X-ray emission from at least some IIPs should reflect the larger end of the high mass-loss rates. Strangely, no IIP SNe are seen where the X-ray luminosity is large enough to suggest mass-loss rates greater than about 10^{-5} M_{⊙} yr-1. We investigate if this could be due to absorption of the X-ray emission. After carefully studying all the various aspects, we conclude that absorption would not be large enough to prevent us from having detected X-ray emission from high mass-loss rate IIPs. This leads us to the conclusion that there may be an upper limit of ˜10^{-5} M_{⊙} yr-1 to the mass-loss rate of Type IIP progenitors, and therefore to the luminosity of RSGs that explode to form Type IIPs. This in turn suggests an upper limit of ≲ 19 M_{⊙} for the progenitor mass of a Type IIP SN. This limit is close to that obtained by direct detection of IIP progenitors, as well as that suggested by recent stellar evolution calculations. Although the statistics need to be improved, many current indicators support the notion that RSGs above ˜ 19 M_{⊙} do not explode to form Type IIP SNe.

  4. Infrared Supernova Remnants and their Infrared-to-X-ray Flux Ratios

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul; Lee, Jae-Joon; Jeong, Il-Gyo; Seok, Ji Yeon; Kim, Hyun-Jeong

    2016-04-01

    Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that are often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs is also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios ({R}{{IRX,obs}}) are related to the IRX morphology, with SNRs with the largest {R}{{IRX,obs}} showing anticorrelated IRX morphology. By analyzing the relation of {R}{{IRX,obs}} to X-ray and IR parameters, we show that the {R}{{IRX,obs}} of some SNRs agrees with theoretical ratios of SNR shocks in which dust grains are heated and destroyed by collisions with plasma particles. For the majority of SNRs, however, {R}{{IRX,obs}} values are either significantly smaller or significantly larger than the theoretical ratios. The latter SNRs have relatively low dust temperatures. We discuss how the natural and/or environmental properties of SNRs could have affected the IRX flux ratios and the IRX morphology of these SNRs. We conclude that the SNRs with largest {R}{{IRX,obs}} are probably located in a dense environment and that their IR emission is from dust heated by shock radiation rather than by collisions. Our result suggests that the IRX flux ratio, together with dust temperature, can be used to infer the nature of unresolved SNRs in external galaxies.

  5. Formation of Black Hole Low-mass X-Ray Binaries in Hierarchical Triple Systems

    NASA Astrophysics Data System (ADS)

    Naoz, Smadar; Fragos, Tassos; Geller, Aaron; Stephan, Alexander P.; Rasio, Frederic A.

    2016-05-01

    The formation of black hole (BH) low-mass X-ray binaries (LMXB) poses a theoretical challenge, as low-mass companions are not expected to survive the common-envelope scenario with the BH progenitor. Here we propose a formation mechanism that skips the common-envelope scenario and relies on triple-body dynamics. We study the evolution of hierarchical triples following the secular dynamical evolution up to the octupole-level of approximation, including general relativity, tidal effects, and post-main-sequence evolution such as mass loss, changes to stellar radii, and supernovae. During the dynamical evolution of the triple system the “eccentric Kozai-Lidov” mechanism can cause large eccentricity excitations in the LMXB progenitor, resulting in three main BH-LMXB formation channels. Here we define BH-LMXB candidates as systems where the inner BH-companion star crosses its Roche limit. In the “eccentric” channel (∼81% of the LMXBs in our simulations) the donor star crosses its Roche limit during an extreme eccentricity excitation while still on a wide orbit. Second, we find a “giant” LMXB channel (∼11%), where a system undergoes only moderate eccentricity excitations but the donor star fills its Roche-lobe after evolving toward the giant branch. Third, we identify a “classical” channel (∼8%), where tidal forces and magnetic braking shrink and circularize the orbit to short periods, triggering mass-transfer. Finally, for the giant channel we predict an eccentric (∼0.3–0.6) preferably inclined (∼40°, ∼140°) tertiary, typically on a wide enough orbit (∼104 au) to potentially become unbound later in the triple evolution. While this initial study considers only one representative system and neglects BH natal kicks, we expect our scenario to apply across a broad region of parameter space for triple-star systems.

  6. Another thread in the tapestry of stellar feedback: X-ray binaries

    NASA Astrophysics Data System (ADS)

    Justham, Stephen; Schawinski, Kevin

    2012-06-01

    We consider X-ray binaries (XBs) as potential sources of stellar feedback. XBs observationally appear able to deposit a high fraction of their power output into their local interstellar medium, which may make them a non-negligible source of energy input. The formation rate of the most luminous XBs rises with decreasing metallicity, which should increase their significance during galaxy formation in the early Universe. We also argue that stochastic effects are important to XB feedback (XBF) and may dominate the systematic changes due to metallicity in many cases. Large stochastic variation in the magnitude of XBF at low absolute star formation rates provides a natural reason for diversity in the evolution of dwarf galaxies which were initially almost identical, with several per cent of such haloes experiencing energy input from XBs roughly two orders of magnitude above the most likely value. These probability distributions suggest that the effect of XBF is most commonly significant for total stellar masses between approximately 107 and 108 M⊙, which might resolve a current problem with modelling populations of such galaxies. We explain how XBs might inject energy before luminous supernovae (SNe) contribute significantly to feedback and how XBs can assist in keeping gas hot long after the last core-collapse SN has exploded. Energy input from XBs produces different behaviour to that from SNe, partly since the peak energy input from a mean XB population continues for ≈100 Myr after the start of a starburst. XBF could be especially important to some dwarf galaxies, potentially heating gas without expelling it; the properties of XBF also match those previously derived as allowing episodic star formation. We also argue that the efficiency of SN feedback (SNF) might be reduced when XBF has had the opportunity to act first. In addition, we note that the effect of SNF is unlikely to be scale-free; galaxies smaller than ≈100 pc might well experience less effective SNF.

  7. X-RAY BINARIES IN THE ULTRAHIGH ENCOUNTER RATE GLOBULAR CLUSTER NGC 6388

    SciTech Connect

    Maxwell, J. Edward; Lugger, Phyllis M.; Cohn, Haldan N.; Heinke, Craig O.; Grindlay, Jonathan E.; Budac, Sonia A.; Drukier, Gordon A.; Bailyn, Charles D. E-mail: lugger@astro.indiana.edu E-mail: heinke@ualberta.ca

    2012-09-10

    We report the results of a joint Chandra Hubble Space Telescope study of the X-ray binary (XRB) population in the massive, high-density globular cluster NGC 6388. NGC 6388 has one of the highest predicted XRB production rates of any Galactic cluster. We detected a large population of 61 Chandra sources within the half-mass radius with L{sub X} > 5 Multiplication-Sign 10{sup 30} erg s{sup -1}. From the X-ray colors, luminosities, (lack of) variability, and spectral fitting, we identify five as likely quiescent low-mass X-ray binaries. Due to the extremely crowded nature of the core of NGC 6388, finding optical identifications to Chandra sources is challenging. We have identified four blue, optically variable counterparts to spectrally hard X-ray sources, evidence that these are bright cataclysmic variables (CVs). One showed variability of 2 mag in V, indicative of a dwarf nova eruption. One other likely CV is identified by its X-ray spectrum (partial covering with high N{sub H}) and strong variability, making five likely CVs identified in this cluster. The relatively bright optical magnitudes of these sources put them in the same class as CV1 in M15 and the brightest CVs in 47 Tuc.

  8. MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072

    SciTech Connect

    Yan Jingzhi; Li Hui; Liu Qingzhong; Zurita Heras, Juan Antonio; Chaty, Sylvain E-mail: hli@pmo.ac.cn E-mail: juan-antonio.zurita-heras@cea.fr

    2012-07-01

    We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

  9. Probing the neutron star spin evolution in the young Small Magellanic Cloud Be/X-ray binary SXP 1062

    NASA Astrophysics Data System (ADS)

    Popov, S. B.; Turolla, R.

    2012-03-01

    The newly discovered Be/X-ray binary in the Small Magellanic Cloud, SXP 1062, provides the first example of a robust association with a supernova remnant (SNR). The short age estimated for the SNR qualifies SXP 1062 as the youngest known source in its class, ?. As such, it allows us to test current models of magnetorotational evolution of neutron stars in a still unexplored regime. Here we discuss possible evolutionary scenarios for SXP 1062 in an attempt to reconcile its long spin period, ?, and short age. Although several options can be considered, like an anomalously long initial period or the presence of a fossil disc, our results indicate that SXP 1062 may host a neutron star born with a large initial magnetic field, typically in excess of ˜ 1014 G, which then decayed to ˜ 1013 G.

  10. Average spectral properties of galactic X-ray binaries with 3 years of MAXI data

    NASA Astrophysics Data System (ADS)

    Islam, Nazma; Mihara, T.; Sugizaki, M.; Paul, B.; Nath, Biman B.

    The energy spectra of X-ray binaries (XRBs) have been investigated during the last few decades with many observatories in different energy bands and with different energy resolutions. However, these studies are carried out in selected states of XRBs like during outbursts, transitions, quiescent states, and are always done in limited time windows of pointed observations. It is now possible to investigate the long term averaged spectra of a large number of X-ray binaries with the all sky monitor MAXI, which also has a broad energy band. Here we present the average spectral behaviour of a few representative XRBs. The long term averaged spectrum of Cyg X-1 is described by a sum of two power-laws having Γ_{1} ˜2.8 and Γ_{2} ˜1.2, along with a multi color disk blackbody having an inner disk temperature of 0.5 keV, GX 301-2 is described by a power-law with a high energy cut-off at E_{c} ˜ 15 keV and a blackbody component at 0.2 keV and that of Aql X-1 is described by a multi color disk blackbody at 2 keV and a power-law of Γ ˜ 2.2. We have also constructed the combined X-ray spectrum of the X-ray binaries in the Milky Way, which can be compared to the XRBs spectra of other galaxies observed with Chandra and XMM-Newton. These measurements are also relevant to investigate the X-ray interaction with the ISM and its contribution to the ionizing X-ray background in the early universe.

  11. Ultra-luminous X-Ray Sources in HARO II and the Role of X-Ray Binaries in Feedback in Lyα Emitting Galaxies

    NASA Astrophysics Data System (ADS)

    Prestwich, A. H.; Jackson, F.; Kaaret, P.; Brorby, M.; Roberts, T. P.; Saar, S. H.; Yukita, M.

    2015-10-01

    Lyman Break Analogs (LBAs) are local proxies of high-redshift Lyman Break Galaxies. Spatially resolved studies of nearby starbursts have shown that Lyman continuum and line emission are absorbed by dust and that the Lyα is resonantly scattered by neutral hydrogen. In order to observe Lyα emission from star-forming regions, some source of feedback is required to blow the neutral gas away from the starburst to prevent scattering and allow the Lyα emission to escape. We show that there are two X-ray point sources embedded in the diffuse emission of the LBA galaxy Haro 11. CXOU J003652.4-333316 (abbreviated to Haro 11 X-1) is an extremely luminous (L{}{{X}}˜ {10}41 erg s-1), spatially compact source with a hard-X-ray spectrum. We suggest that the X-ray emission from Haro 11 X-1 is dominated by a single accretion source. This might be an active galactic nucleus or a source similar to the extreme black hole binary (BHB) M82 X-1. The hard X-ray spectrum indicates that Haro 11 X-1 may be a BHB in a low accretion state. In this case, the very high X-ray luminosity suggests an intermediate mass black hole that could be the seed for formation of a supermassive black hole. Source CXOU J003652.7-33331619.5 (abbreviated Haro 11 X-2) has an X-ray luminosity of {L}{{X}}˜ 5× {10}40 erg s-1 and a soft X-ray spectrum (power-law photon index Γ ˜ 2.2). This strongly suggests that Haro 11 X-2 is an X-ray binary in the ultra luminous state (i.e., an Ultra Luminous X-ray source, ULX). Haro 11 X-2 is coincident with the star-forming knot that is the source of the Lyα emission. The association of a ULX with Lyα emission raises the possibility that strong winds from X-ray binaries play an important role in injecting mechanical power into the interstellar medium, thus blowing away neutral material from the starburst region and allowing the Lyα to escape. We suggest that feedback from X-ray binaries may play a significant role in allowing Lyα emission to escape from galaxies in the

  12. Swift/BAT Detection of Hard X-Rays from Tycho's Supernova Remnant: Evidence for Titanium-44

    NASA Astrophysics Data System (ADS)

    Troja, E.; Segreto, A.; La Parola, V.; Hartmann, D.; Baumgartner, W.; Markwardt, C.; Barthelmy, S.; Cusumano, G.; Gehrels, N.

    2014-12-01

    We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10σ) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.

  13. A Broadband X-Ray Study of Supernova Remnant 3C 397

    NASA Astrophysics Data System (ADS)

    Safi-Harb, S.; Petre, R.; Arnaud, K. A.; Keohane, J. W.; Borkowski, K. J.; Dyer, K. K.; Reynolds, S. P.; Hughes, J. P.

    2000-12-01

    We present a broadband imaging and spectral study of the radio-bright supernova remnant (SNR) 3C 397 with ROSAT, ASCA, and RXTE. A bright X-ray spot seen in the HRI image hints at the presence of a pulsar-powered component and gives this SNR a composite X-ray morphology. Combined ROSAT and ASCA imaging shows that the remnant is highly asymmetric, with its X-ray emission peaking at the western lobe. The hard-band images obtained with the ASCA Gas Imaging Spectrometer show that much of the hard X-ray emission arises from the western lobe, associated with the SNR shell, with little hard X-ray emission associated with the central hot spot. The spectrum from 3C 397 is heavily absorbed and dominated by thermal emission with emission lines evident from Mg, Si, S, Ar and Fe. Single-component models fail to describe the X-ray spectrum, and at least two components are required: a soft component characterized by a low temperature and a large ionization timescale, and a hard component required to account for the Fe-K emission line and characterized by a much lower ionization timescale. We use a set of nonequilibrium ionization (NEI) models (Borkowski et al., in preparation), and find that the fitted parameters are robust. The temperatures from the soft and hard components are ~0.2 keV and ~1.6 keV respectively. The corresponding ionization timescales n0t (n0 being the preshock hydrogen density) are ~6×1012 cm-3 s and ~6×1010 cm-3 s, respectively. The large n0t of the soft component suggests it is approaching ionization equilibrium; thus it can be fit equally well with a collisional equilibrium ionization model. The spectrum obtained with the Proportional Counter Array (PCA) of RXTE is contaminated by emission from the Galactic ridge, with only ~15% of the count rate originating from 3C 397 in the 5-15 keV range. The PCA spectrum allowed us to confirm the thermal nature of the hard X-ray emission. A third component originating from a pulsar-driven component is possible, but

  14. A Search for X-ray Emitting Binary Stars in the Globular Cluster Omega Centauri

    NASA Astrophysics Data System (ADS)

    Deveny, Sarah; Gallien, Michael; Rickards Vaught, Ryan; Waters, Miranda; Cool, Adrienne; Bellini, Andrea; Anderson, Jay; Henleywillis, Simon; Haggard, Daryl; Heinke, Craig O.

    2016-06-01

    Omega Centauri is one of the most widely studied globular clusters, and is expected to harbor a significant population of binary stars. Binaries play a crucial role in determining the progression of stellar dynamics within globular clusters, and as such are relevant to questions concerning the possible formation of intermediate black holes at their centers. One effective way to identify certain classes of binary systems is to first locate X-ray sources in the cluster and then to search for their optical counterparts. Using Chandra X-ray Observatory's ACIS-I instrument we have identified 275 X-ray sources in and toward Omega Cen, more than 50 of which lie within the cluster's core radius. Here we present a search for the optical counterparts of these core sources using an extensive database of archival Hubble Space Telescope images. Using WFC3/UVIS data from 11 different filters, we construct color-magnitude diagrams that reveal a diverse array of objects, including (in addition to background and foreground objects) cataclysmic variables, coronally active binaries, and, interestingly, stars that lie on Omega Cen's anomalous giant branch. We discuss the significance of these results in the context of studies of the formation and evolution of binary stars in globular clusters.

  15. Enhanced winds and tidal streams in massive X-ray binaries

    SciTech Connect

    Blondin, J.M.; Stevens, I.R.; Kallman, T.R. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1991-04-01

    The tidal effects created by the presence of a compact companion are expected to induce a stream of enhanced wind from the early-type primary star in massive X-ray binary systems. In this paper, two-dimensional gasdynamical simulations of such streams are presented. It is found that the wind enhancement is a sensitive function of the binary separation, and develops into a tidal stream as the primary approaches its critical surface. For typical system parameters, the Coriolis force deflects the stream sufficiently that it does not impact directly on the compact companion but passes behind it. The density in the stream can reach values of 20-30 times the ambient wind density, leading to strong attenuation of the X-ray flux that passes through the tidal stream, providing a possible explanation of the enhanced absorption events seen at later phases in the X-ray observations of massive X-ray binary systems such as Vela X-1. In contrast to the time-variable accretion wake, the tidal stream is relatively stationary, producing absorption features that should remain fixed from orbit to orbit. For systems with a strong tidal stream, the large asymmetry in the accreting wind results in the accretion of angular momentum of constant sign, as opposed to systems without streams, where the sign of the accreted angular momentum can change. 39 refs.

  16. A Global Look at Reflection in Black-Hole X-ray Binaries Using RXTE

    NASA Astrophysics Data System (ADS)

    Steiner, James F.; Garcia, Javier; Reis, Ruben C.; McClintock, Jeffrey E.

    2014-08-01

    Spectral reflection is ubiquitous in black-hole X-ray binaries, and is produced by the coronal hard X-ray emission illuminating the cooler accretion disk. The observed interplay between coronal and reflection spectral components provides insight into the geometry of the corona - an attribute which is presently only weakly constrained We present first results from a new campaign analyzing all RXTE PCU-2 spectra of accreting stellar-mass black holes. A simple but self-consistent treatment of disk, coronal, and reflection emission highlights changes evident in the coronal geometry between soft and hard spectral states.

  17. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. II. X-Ray Variability

    NASA Astrophysics Data System (ADS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Nazé, Y.; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Richardson, N. D.; Pablo, H.; Evans, N. R.; Hamaguchi, K.; Gull, T.; Hamann, W.-R.; Oskinova, L.; Ignace, R.; Hoffman, Jennifer L.; Hole, K. T.; Lomax, J. R.

    2015-08-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the δ Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of ≈ 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 Å is confirmed, with a maximum amplitude of about ±15% within a single ≈ 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S xv, Si xiii, and Ne ix. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at ϕ = 0.0 when the secondary δ Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind-wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability. Based on data from the Chandra X-ray Observatory and the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

  18. The coupling of a disk corona and a jet for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin

    2015-08-01

    We interpret the radio/X-ray correlation of LR ∝ LX1.4 for LX/LEdd >10-3 in black hole X-ray binaries with a detailed disk corona-jet model, in which the accretion flow and the jet are connected by a parameter, ‘η’, describing the fraction of the matter in the accretion flow ejected outward to form the jet. We calculate LR and LX at different mass accretion rates, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for LX/LEdd > 10-3. It is found that the value of η for this radio/X-ray correlation for LX/LEdd > 10-3, is systematically less than that of the case for LX/LEdd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high luminosity phase in black hole X-ray binaries.

  19. Quantitative measurement of binary liquid distributions using multiple-tracer x-ray fluorescence and radiography

    SciTech Connect

    Halls, Benjamin R.; Meyer, Terrence R.; Kastengren, Alan L.

    2015-01-01

    The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of x-ray fluorescence reabsorption is compared with a more time-intensive approach of using stereographic reconstruction of x-ray attenuation along multiple lines of sight. The proposed methodology addresses the need for a quantitative measurement technique capable of interrogating optically complex, near-field liquid distributions in many mixing systems of practical interest involving two or more liquid streams.

  20. The X-ray properties of five galactic supernova remnants detected by the Spitzer glimpse survey

    SciTech Connect

    Pannuti, Thomas G.; Moffitt, William P.; Rho, Jeonghee; Heinke, Craig O. E-mail: w.moffitt@moreheadstate.edu E-mail: heinke@ualberta.ca

    2014-03-01

    We present a study of the X-ray properties of five Galactic supernova remnants (SNRs)—Kes 17 (G304.6+0.1), G311.5–0.3, G346.6–0.2, CTB 37A (G348.5+0.1), and G348.5–0.0—that were detected in the infrared by Reach et al. in an analysis of data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) that was conducted by the Spitzer Space Telescope. We present and analyze archival ASCA observations of Kes 17, G311.5–0.3, and G346.6–0.2, archival XMM-Newton observations of Kes 17, CTB 37A, and G348.5–0.0, and an archival Chandra observation of CTB 37A. All of the SNRs are clearly detected in the X-ray except possibly G348.5–0.0. Our study reveals that the four detected SNRs all feature center-filled X-ray morphologies and that the observed emission from these sources is thermal in all cases. We argue that these SNRs should be classified as mixed-morphology SNRs (MM SNRs); our study strengthens the correlation between MM SNRs and SNRs interacting with molecular clouds and suggests that the origin of MM SNRs may be due to the interactions between these SNRs and adjacent clouds. Our ASCA analysis of G311.5–0.3 reveals for the first time X-ray emission from this SNR: the X-ray emission is center-filled within the radio and infrared shells and thermal in nature (kT ∼ 0.98 keV), thus motivating its classification as an MM SNR. We find considerable spectral variations in the properties associated with the plasmas of the other X-ray-detected SNRs, such as a possible overabundance of magnesium in the plasma of Kes 17. Our new results also include the first detailed spatially resolved spectroscopic study of CTB 37A using Chandra as well as a spectroscopic study of the discrete X-ray source CXOU J171428.5–383601, which may be a neutron star associated with CTB 37A. Finally, we also estimate such properties as electron density n{sub e} , radiative age t {sub rad} and swept-up mass M{sub X} for each of the four X-ray-detected SNRs. Each

  1. Energetic Particle Acceleration in X-Ray BINARIES:JOINT X-Ray and Gamma-Ray Observations of CEN X-3

    NASA Astrophysics Data System (ADS)

    Vestrand, W. Thomas

    Recent detections of gamma-ray emission from the Cen X-3 system have focussed new attention on x-ray binary systems as possible sites for powerful energetic particle acceleration. Simultaneous x-ray and gamma- ray observations are needed to constrain models for particle acceleration and high-energy photon production within the Cen X-3 system. We propose modest RXTE x-ray monitoring observations as part of an international campaign to measure simultaneously the high-enegy emission from Cen X-3 at x-ray through TeV energies. This broad-band dataset will be a unique resource for modeling high-energy processes in the Cen X-3 system.

  2. Simultaneous X-Ray and Radio Observations of the Unusual Binary LSI + 61 deg 303

    NASA Technical Reports Server (NTRS)

    Harrison, Fiona A.; Leahy, Denis A.; Waltman, Elizabeth

    1996-01-01

    We present simultaneous 0.5 - 10 keV X-ray and two-frequency radio observations at 2.25 and 8.3 GHz of the unusual binary system LSI + 61 deg. 303. This system was observed twice in a single binary orbit by the ASCA satellite, and monitored daily at two radio frequencies during the same orbital cycle with the Greenbank Interferometer. During the first ASCA observation the source was detected with a 1 - 10 keV luminosity 3.6 x 10(exp 33) (d/2.0 kpc)(exp 2) erg 1/s and during the second at a similar level with evidence for a decrease in average flux of 30%. During the first pointing the radio source was at a quiescent 8 GHz flux level of 30 mJy while during the second the radio flux was rising dramatically with an average value of 100 mJy. No variability is seen in the X-ray flux during the first pointing, but during the second the flux is variable by approx. 50% on timescales of approx. 30 minutes. No pulsations are seen in either X-ray observation with an upper limit on pulsed flux of 20%. The low X-ray luminosity and lack of observed pulsations indicate that accretion onto a neutron star surface is not the origin for the high-energy emission. Rather, the X-rays must result either from accreted matter which is stopped at the magnetosphere because the magnetospheric boundry is rotating at super-Keplerian rates or due to a shock formed in the interaction of the dense wind of the Be star companion and a moderately young pulsar. We derive a required pulsar spin down luminosity of approx. 10(exp 37) erg 1/s, and argue that the shock model more easily explains the observed X-ray radio observations.

  3. Rapid spectral and timing variability of Be/X-ray binaries during type ;II outbursts

    NASA Astrophysics Data System (ADS)

    Reig, P.

    2008-10-01

    X-ray colour-colour (CD) and colour-intensity (HID) diagrams are powerful tools that allow investigation of spectral variability without assuming any spectral model. These diagrams have been used extensively for low-mass X-ray binaries and black-hole candidates, but very few applications have been found for high-mass X-ray binaries. We investigated the spectral and timing variability of four accreting X-ray pulsars with Be-type companions during major X-ray outbursts. The aim is to define source states based on the properties (noise components) of the aperiodic variability in correlation with the position in the colour-colour diagram. Different spectral states were defined according to the value of the X-ray colours and flux. Transient Be/X-ray binaries exhibit two branches in their colour-colour and colour-intensity diagrams: i) the horizontal branch corresponds to a low-intensity state and shows the highest fractional rms, similar to the the island state in atolls and horizontal branch in Z sources; ii) the diagonal branch corresponds to a high-intensity state, in which the source stays for about 75% of the total duration of the outburst. Despite the complexity of the power spectra due to the peaks of the pulse period and its harmonics, the aperiodic variability of Be/X-ray binaries can be described with a relatively low number of Lorentzian components. Some of these components can be associated with the same type of noise as seen in low-mass X-ray binaries, although the characteristic frequencies are about one order of magnitude lower. The analysis of the CD/HID and power spectra results in two different types of Be/X. While in 4U 0115+63, KS 1947+300 and EXO 2030+375 the hard colour decreases as the count rate decreases, it increases in V0332+53. The pattern traced by V0332+53 then results in a Z-shaped track, similar to the low-mass Z sources, without the flaring branch. In contrast, the horizontal branch in 4U 0115+63, KS 1947+300 and EXO 2030+375 corresponds

  4. ENERGY FEEDBACK FROM X-RAY BINARIES IN THE EARLY UNIVERSE

    SciTech Connect

    Fragos, T.; Zezas, A.; Lehmer, B. D.; Naoz, S.; Basu-Zych, A.

    2013-10-20

    X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z ∼ 20) until today. We estimate that X-ray emission from XRBs dominates over AGN at z ∼> 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by ∼4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of ∼300 Myr and then decreases gradually at later times, showing little variation for mean stellar ages ∼> 3 Gyr. Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

  5. Energy Feedback from X-Ray Binaries in the Early Universe

    NASA Astrophysics Data System (ADS)

    Fragos, T.; Lehmer, B. D.; Naoz, S.; Zezas, A.; Basu-Zych, A.

    2013-10-01

    X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z ~ 20) until today. We estimate that X-ray emission from XRBs dominates over AGN at z >~ 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by ~4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of ~300 Myr and then decreases gradually at later times, showing little variation for mean stellar ages >~ 3 Gyr. Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

  6. Tracing the Reverberation Lag in the Hard State of Black Hole X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    De Marco, B.; Ponti, G.; Muñoz-Darias, T.; Nandra, K.

    2015-11-01

    We report results obtained from a systematic analysis of X-ray lags in a sample of black hole X-ray binaries, with the aim of assessing the presence of reverberation lags and studying their evolution during outburst. We used XMM-Newton and simultaneous Rossi X-ray Timing Explorer (RXTE) observations to obtain broadband energy coverage of both the disk and the hard X-ray Comptonization components. In most cases the detection of reverberation lags is hampered by low levels of variability-power signal-to-noise ratio (typically when the source is in a soft state) and/or short exposure times. The most detailed study was possible for GX 339-4 in the hard state, which allowed us to characterize the evolution of X-ray lags as a function of luminosity in a single source. Over all the sampled frequencies (˜0.05-9 Hz), we observe the hard lags intrinsic to the power-law component, already well known from previous RXTE studies. The XMM-Newton soft X-ray response allows us to detail the disk variability. At low frequencies (long timescales) the disk component always leads the power-law component. On the other hand, a soft reverberation lag (ascribable to thermal reprocessing) is always detected at high frequencies (short timescales). The intrinsic amplitude of the reverberation lag decreases as the source luminosity and the disk fraction increase. This suggests that the distance between the X-ray source and the region of the optically thick disk where reprocessing occurs gradually decreases as GX 339-4 rises in luminosity through the hard state, possibly as a consequence of reduced disk truncation.

  7. Energy Feedback from X-ray Binaries in the Early Universe

    NASA Technical Reports Server (NTRS)

    Fragos, T.; Lehmer, B..; Naoz, S.; Zezas, A.; Basu-Zych, A.

    2013-01-01

    X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z (redshift) approximately equal to 20) until today.We estimate that X-ray emission from XRBs dominates over AGN at z (redshift) greater than or approximately equal to 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by approximately 4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of approximately 300 Myr (million years) and then decreases gradually at later times, showing little variation for mean stellar ages 3 Gyr (Giga years, or billion years). Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

  8. Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

    NASA Technical Reports Server (NTRS)

    Thomas, Brian; Corbet, Robin; Augusteijn, Thomas; Callanan, Paul; Smale, Alan P.

    1993-01-01

    Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state, while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve.

  9. IGR J17451–3022: a dipping and eclipsing low mass X-ray binary

    NASA Astrophysics Data System (ADS)

    Bozzo, E.

    2016-06-01

    We report on the available X-ray data collected by INTEGRAL, Swift, and XMM-Newton during the first outburst of the INTEGRAL transient IGR J17451-3022, discovered in 2014 August. The emission of the source during the 9 months-long outburst was dominated by a thermal component (kT˜1.2 keV), most likely produced by an accretion disk. The XMM-Newton observation carried out during the outburst revealed the presence of multiple absorption features in the soft X-ray emission that could be associated to the presence of an ionized absorber lying above the accretion disk, as observed in many high-inclination low mass X-ray binaries. The XMM-Newton data also revealed the presence of partial and rectangular X-ray eclipses (lasting about 820 s), together with dips. The latter can be associated with increases in the overall absorption column density in the direction of the source. The detection of two consecutive X-ray eclipses in the XMM-Newton data allowed us to estimate the source orbital period at Porb=22620.5(‑1.8,+2.0) s (1σ c.l.).

  10. IGR J17451-3022: a dipping and eclipsing low mass X-ray binary

    NASA Astrophysics Data System (ADS)

    Bozzo, E.

    2016-06-01

    We report on the available X-ray data collected by INTEGRAL, Swift, and XMM-Newton during the first outburst of the INTEGRAL transient IGR J17451-3022, discovered in 2014 August. The emission of the source during the 9 months-long outburst was dominated by a thermal component (kT˜14;1.2 keV), most likely produced by an accretion disk. The XMM-Newton observation carried out during the outburst revealed the presence of multiple absorption features in the soft X-ray emission that could be associated to the presence of an ionized absorber lying above the accretion disk, as observed in many high-inclination low mass X-ray binaries. The XMM-Newton data also revealed the presence of partial and rectangular X-ray eclipses (lasting about 820 s), together with dips. The latter can be associated with increases in the overall absorption column density in the direction of the source. The detection of two consecutive X-ray eclipses in the XMM-Newton data allowed us to estimate the source orbital period at Porb=22620.5(-1.8,+2.0) s (1σ c.l.).