Conveners
15 - Binaries: HMXB
- Alessandro Papitto
15 - Binaries: HXMXB
- Alessandro Papitto
15 - Binaries: ULX and LMXB
- Alessandro Papitto
15 - Binaries: ULX and LMXB
- Alessandro Papitto
15 - Binaries: Millisecond pulsars
- Alessandro Papitto
15 - Binaries: Millisecond pulsars
- Alessandro Papitto
Prof.
Diego Torres
(ICREA / Institute of Space Sciences)
05/12/2015, 14:00
Talk
Detected from radio to TeV gamma rays, the gamma-ray binary LS I + 61º303 is highly variable across all frequencies. Beside its variability due to the modulation of its emission due to the 26.496-day orbital period, the system also presents variability consistent with the so-called superorbital period, of 1667 days. We will present the latest data set of LSI +61º 303 taken with the Fermi Large...
Guillaume DUBUS
(IPAG CNRS/Université Grenoble Alpes)
05/12/2015, 14:26
Talk
The presence of a relativistic pulsar wind has been established in several X-ray binaries. The interaction of the pulsar wind with the stellar companion, stellar wind, or accretion disk can lead to peculiar signatures, most prominently the emission of high-energy gamma-rays. I will describe our efforts to model this interaction in order to translate gamma-ray observations into a better...
Pere Munar-Adrover
(INAF-IAPS)
05/12/2015, 14:52
Talk
MWC 656 is a Be star with a black hole (BH) companion, being the first and unique Be/BH binary system found. The detected X-ray counterpart implies that MWC 656 is, as well, the first Be/BH X-ray binary found. We carried out a search in archival AGILE data and found ten gamma-ray flares compatible with the position of the binary system, although no periodicity in the gamma-ray activity has...
Friedrich Thielemann
(University of Basel)
05/12/2015, 15:18
Talk
The origin of the heavy elements made by the rapid neutron-capture process (”r-process”) is not fully understood, yet. Different sources have been proposed, e.g., core-collapse supernovae as well as neutron star mergers.
- We discuss the production of r-process elements in three of these suggested sites:
1.the neutrino wind in core collapse supernovae, 2. jet ejecta from...
Patrizia Romano
(INAF)
05/12/2015, 16:15
Talk
We present the results of the Swift Supergiant Fast X-ray Transients project,
which has been exploiting *Swift*'s capabilities in a systematic study of SFXTs and classical
supergiant X-ray binaries (SGXBs) since 2007.
The unique combination of sensitivity and scheduling flexibility of *Swift*/XRT
allowed us to perform an efficient long-term monitoring of 16 including both SFXTs and...
Alexander Lutovinov
(Space Research Institute)
05/12/2015, 16:40
Talk
Review of the most prominent results obtained with the INTEGRAL observatory for high-mass X-ray binary systems (HMXBs) is presented. Hard X-ray observations by INTEGRAL have broadened significantly our knowledge about X-ray binaries in the Milky Way. During dozen years the observatory discovered new types and populations of binary systems, like supergiant fast x-ray transients, heavily...
Ms
Pragati Pradhan
(St. Joseph's College, Darjeeling, India & North Bengal University, Siliguri, India)
05/12/2015, 17:25
Talk
We present a broadband spectral analysis of classical HMXBs (supergiant and
Be/X-ray binaries) and Supergiant Fast X-ray Transients (SFXTs) using data
from XIS and PIN instruments onboard Suzaku. After fitting the X-ray spectra
of 36 sources with a single model: a powerlaw and a high energy cutoff (where
required), we studied the correlation between various spectral parameters.
We present...
Ms
Nazma Islam
(Indian Institute of Science, Raman Research Institute, Bangalore, India)
05/12/2015, 17:45
Talk
GX 301-2, a bright high-mass X-ray binary with an orbital period of 41.5 days, exhibits stable periodic orbital intensity modulations with a strong pre-periastron X-ray flare. Several models have been proposed to explain the accretion at different orbital phases, invoking accretion via stellar wind, equatorial disc, and accretion stream from the companion star. We present results from...
Chandreyee Maitra
(CEA Saclay)
05/12/2015, 18:05
Talk
We present detailed broadband timing and spectral analysis of the persistent, low luminosity and slowly spinning pulsar 'X-per' using a Suzaku observation of the source. The spectrum is unusually hard with pulsations detected up to 70 keV. The spectrum also hosts several interesting features like evidence of a cyclotron line at 30 keV, and presence of a soft-excess below 2 keV. Considering...
Ms
Nazma Islam
(Indian Institute of Science, Raman Research Institute, India)
05/12/2015, 18:20
Poster
In the absence of detectable pulsations in the eclipsing High Mass X-ray binary 4U 1700–37, the orbital period decay is necessarily determined from the eclipse timing measurements. We have used the earlier reported mid-eclipse time measurements of 4U 1700–37 together with new measurements from long term light curves obtained with the all sky monitors RXTE–ASM, Swift–BAT and MAXI–GSC, as well...
Ileyk EL MELLAH
(Paris 7 Diderot - APC laboratory)
05/12/2015, 18:24
Poster
Compact objects in high mass X-ray binaries (HMXB), where the companion star underfills its Roche lobe, have been spotted as X-ray emitters, probably due to the presence of a surrounding disc, along with their low mass counterparts (LMXB). However, if the disc formation is well understood in LMXB where matter is poured through the first Lagrangian point, things get messier in HMXB,...
Matteo Bachetti
(INAF/Osservatorio Astronomico di Cagliari)
06/12/2015, 14:00
Talk
M82 X-2, an ultraluminous X-ray source in M82, was recently shown to harbor an accreting neutron star. Its luminosity being ~100 times the Eddington limit for a neutron star, it poses some problems to the existing theoretical framework about accretion onto neutron stars.
I will talk about the proprieties and behavior of this source, how it was unveiled as a neutron star, the possible...
Andrew Sutton
(NASA Marshall Space Flight Center)
06/12/2015, 14:25
Talk
There are now strong arguments that many ultraluminous X-ray sources (ULXs) are powered by super-Eddington accretion on to stellar remnant black holes. However, a key remaining question is: how are the classic sub-Eddington and new super-Eddington accretion states related? In an attempt to answer this, we present results from a systematic analysis of samples of the brightest thermal dominant...
Rudy Wijnands
(University of Amsterdam)
06/12/2015, 14:50
Talk
I will present our results of our studies on the spectral properties of neutron star low-mass X-ray binaries when they have accretion luminosities between 1e34 and 1e36 erg/s (roughly 0.01 - 1 percent Eddington). We found that their photon index increases with decreasing 0.5-10 keV luminosity (the spectrum softens). Such behaviour has been reported for individual sources, but we now...
Prof.
Tiziana Di Salvo
(University of Palermo)
06/12/2015, 15:20
Talk
We will present spectral and timing analysis of NuSTAR and XMM-Newton data of the Accreting Millisecond Pulsar SAX J1808.4-3658 during its latest outburst in April 2015.
We will discuss a high-quality broad band (2-80 keV) spectrum where the reflection component is clearly present, in line with previous results.
Using DDT XMM-Newton data, we derived updated values for the spin and the...
Norbert S. Schulz
(Massachusetts Institute of Technology)
06/12/2015, 16:15
Talk
4U 1626-67 is an ultra-compact binary pulsar with a pulse period
of 7.7 sec and an orbital period of 40 min. Its X-ray spectrum
varies distinctively before and after torque
reversal episodes. 4U 1626-67 is a peculiar ultra-compact binary
in that it not only truncates its accretion disk at the magnetospheric
radius, but also emits Ne and O Doppler X-ray lines, The nature of
these lines...
Dr
Filippos Koliopanos
(Research Institute in Astrophysics and Planetology (IRAP), Toulouse, France)
06/12/2015, 16:35
Talk
We have discovered strong indications of a correlation between the appearance of the Fe Kα emission line in the spectrum of the X-ray pulsar 4U 1626-67 and its luminosity and shape of its pulse profile. Spectroscopic analysis of the latest, simultaneous Chandra/RXTE observation of 4U 1626-67, revealed the presence of a narrow Fe Kα emission line. The observation was performed when the source...
Prof.
Rosario Iaria
(Univ. di Palermo - DSFC)
06/12/2015, 16:55
Talk
The ultra-compact dipping source XB 1916-053 has an orbital period of
close to 50 min and a companion star with a very low mass (less
than 0.1 M$_{\odot}$). The known orbital period derivative
($1.5(3) \times 10^{-11}$ s/s) is extremely large and can be
explained by invoking an extreme, non-conservative mass transfer
rate that is not
easily justifiable. We extended the...
Dr
Fiamma Capitanio
(IAPS-INAF)
06/12/2015, 17:15
Talk
4U 1630–472 is a recurrent X-ray transient classified as a black hole candidate from its spectral and timing properties. One of the peculiarities of this source is the presence of regular outbursts
with a recurrence period between 600 and 730 d that has been observed since the discovery of the source in 1969. We report on a comparative study, performed with INTEGRAL and RXTE, of the spectral...
Lorenzo Ducci
(University of Tuebingen)
06/12/2015, 17:35
Talk
Glitches have been observed in isolated pulsars, while a
clear detection in accretion-powered X-ray pulsars is still lacking.
We use the "snowplow" model for pulsar glitches of Pizzochero
(2011) and starquake models to determine for the first time the
expected properties of glitches in accreting pulsars. We also
investigate the possibility that anti-glitches occur in accreting
pulsars...
Anastasios Fragkos
(University of Geneva)
06/12/2015, 17:51
Talk
In recent years, an increasing number of proper motions have been measured for Galactic black hole (BH) X-ray binaries (XRBs). When supplemented with accurate determinations of the component masses and spin rates, orbital period, and donor luminosity and effective temperature, these kinematical constraints harbor a wealth of information on the systems’ past evolution. We developed an analysis...
Kadri Yakut
(University of EGE),
Tuğçe İÇLİ
06/12/2015, 18:08
Poster
In this study, we present angular momentum loss mechanism through gravitational radiation for the selected system with neutron stars and gravitational radiation time-scale is estimated for them.
Dr
Jason Hessels
(University of Amsterdam)
07/12/2015, 14:00
Talk
As the most rapidly rotating stars known, millisecond pulsars continue
to enjoy great scientific interest and broad impact. They acquire
their millisecond rotational periods through mass transfer from a
binary stellar companion; via their radio, X-ray and/or gamma-ray
pulsations we can precisely time their spin rate and orbital motion
around a companion object (or even multiple...
Joeri van Leeuwen
(ASTRON / U. Amsterdam)
07/12/2015, 14:30
Talk
PSR J1906+0746 is a young pulsar in the relativistic binary with the second-shortest known orbit, of 3.98 hours. We will present a timing study based on five years of observations, conducted with the 5 largest radio telescopes in the world, aimed at determining the companion nature (van Leeuwen et al. 2015). Through the measurement of three post-Keplerian orbital parameters we find the pulsar...
Marina Berezina
(Max Planck Institute for Radio Astronomy)
07/12/2015, 14:55
Talk
We report on the two new MSP discoveries from the High Time Resolution Universe survey for pulsars and fast transients in the northern hemisphere (HTRU-North), being conducted with the 100-m Effelsberg telescope (Barr et al, 2013). The survey has so far resulted in the total number of 17 new pulsars. Here we present timing solutions for PSR J2045+3633 and PSR J2053+4650, both binary systems...
Prof.
Wim Hermsen
(SRON Netherlands Institute for Space Research, Utrecht, The Netherlands)
07/12/2015, 15:15
Talk
With XMM-Newton, GMRT and LOFAR observations of the mode-changing near-aligned pulsar PSR B0943+10 we discovered synchronous switching in the radio and X-ray emission properties (Hermsen et al. 2013). These extraordinary findings were reported to support radio indications for rapid, global changes to the conditions in the magnetosphere. However, there is still no consistent interpretation for...
Thomas Tauris
(Uni. Bonn)
07/12/2015, 16:15
Talk
Radio millisecond pulsars (MSPs) have been spun-up to very high rotation frequencies
via accretion of mass and angular momentum from a companion star in a binary system.
In this talk, I will review the formation of MSPs and discuss recent observational
and theoretical challenges in understanding their formation and evolution via the
standard recycling scenario. I will discuss MSP...
Dr
Alessandro Papitto
(Space Science Institute Barcelona (ICE) CSIC-IEEC)
07/12/2015, 16:45
Talk
Neutron stars in low mass X-ray binaries can be spun-up to millisecond rotational periods by accreting the matter transferred by a companion star. When the rate of mass transfer decreases at the end of this Gyr-long X-ray bright phase, a radio pulsar powered by the rotation of the neutron star magnetic field turns on. Recently, the evolutionary link between these two classes of sources was...
Carlo Ferrigno
(University of Geneva)
07/12/2015, 17:10
Talk
The pulsar IGR J18245$-$2452 was dubbed as transitional, after detection of X-ray accretion induced pulsations, during an outburst which interrupted radio, rotationally-powered emission. The source was observed at the peak of its X-ray flux using XMM-Newton twice for a total exposure of 90 ks. At odds with other accreting millisecond pulsars, its power spectrum is characterised by a strong...
Dr
Kyle Parfrey
(Lawrence Berkeley National Laboratory)
07/12/2015, 17:30
Talk
The interaction of a rotating star's magnetic field with a surrounding plasma disc lies at the heart of many questions posed by neutron stars in X-ray binaries. I will present global simulations of this interaction, performed in the force-free (high-magnetization) limit of relativistic MHD, showing the opening of magnetic field lines, the formation and reconnection of magnetospheric current...
amruta jaodand
(ASTRON- Netherlands Institute for Radio Astronomy)
07/12/2015, 17:50
Talk
Recently, Bogdanov $\&$ Halpern (2015) identified the unassociated Fermi gamma-ray source $3$FGL~J$1544.6-1125$ as only the $4$th known "transitional millisecond pulsar" (tMSP), a claim further bolstered by follow-up observations by Bogdanov (2015). The tMSPs are a newly discovered class of binary systems that transition between states as a radio millisecond pulsar and a low-mass X-ray binary...
Dr
Zorawar Wadiasingh
(Centre for Space Research, North-West University)
07/12/2015, 18:05
Talk
Searches of unidentified Fermi sources have vastly expanded the number of known galactic-field “black widow” and “redback” circular MSP binary systems. We model the high-energy emission from these systems due to relativistic leptons in the pulsar wind and those accelerated in intrabinary shocks. We show that the observed radio eclipses of the MSP can constrain the shock and system geometry....
Ms
Marilyn Cruces
(Instituto de Astrofísica, Pontificia Universidad Católica de Chile)
07/12/2015, 18:20
Talk
Millisecond pulsars (MSPs) are old and very fast rotating neutron stars (NS) with much weaker magnetic fields than the younger classical pulsars and magnetars. Most MSPs are in binary systems, suggesting a "recycling scenario", in which a classical pulsar accretes matter from its companion and as a consequence spins up. Although this scenario explains the fast rotation, it is not clear yet how...
Prof.
Abd El Fady Morcos
(Emeritus Prof. of Relativistic Astrophysics and Cosmology)
07/12/2015, 18:35
Poster
A generalized formula for Kermack, McCrea and Whittaker (KMW), has been derived by the author and et al., to study the limb effect of rapidly rotating stars. In this work a modified Curzon exact solution for Einstein's field equations has been used to study the variation in the frequencies of signals' carriers from a relativistic binary system. The primary star is assumed to be massive with...
Ms
Marilyn Cruces
(Instituto de Astrofísica, Pontificia Universidad Católica de Chile)
07/12/2015, 18:38
Poster
The XMM-Newton space telescope is capable of 30-microsecond time resolution but its onboard clock drifts, for example due to changes in temperature. Current calibration documentation only provides an upper limit on the clock drift of 10^-8, but observations of X-ray millisecond pulsars (MSPs) suggest that it should be more stable.
Using kilo-second XMM-Newton observations of MSPs taken...
John Cannizzo
(UMBC)
07/12/2015, 18:41
Poster
The study of AM CVn stars - semi-detached He WD-WD binaries - has exploded in recent years
thanks to long term light curves obtained by the Palomar Transient Factory. Systems are seen with
binary periods ranging from about 5 minutes to about an hour. AM CVn stars are similar to dwarf novae
in that they can undergo accretion disk outbursts. Systems with high dM/dt have steady disks...
