Exploring the Nature of Weak Chandra Sources Near the Galactic Centre

We present early results from the first near-IR imaging of the weak X-ray sources discovered in the recent Chandra/ACIS-I survey towards the Galactic Centre (GC) (Wang et al. 2002). These ~800 discrete sources, which contribute significantly to the GC X-ray emission, represent an important and previously unknown population within the Galaxy. From our VLT observations we will identify likely IR counterparts to a sample of the hardest sources, which are most likely X-ray binaries. With these data we can place constraints on the nature of the discrete weak X-ray source population of the GC. Once the data analysis is complete we will discuss our results in the context of binary population synthesis models.

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Magnesium and silicon in interstellar dust: X-ray overview

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936805 ◽

2020 ◽

Vol 641 ◽

pp. A149

Author(s):

D. Rogantini ◽

E. Costantini ◽

S. T. Zeegers ◽

M. Mehdipour ◽

I. Psaradaki ◽

...

Keyword(s):

Cross Sections ◽

Interstellar Dust ◽

Galactic Centre ◽

X Rays ◽

Dust Grains ◽

Large Reservoir ◽

X Ray ◽

Synchrotron Facility ◽

The Galaxy ◽

X Ray Binaries

Context. The dense Galactic environment is a large reservoir of interstellar dust. Therefore, this region represents a perfect laboratory to study the properties of cosmic dust grains. X-rays are the most direct way to detect the interaction of light with dust present in these dense environments. Aims. The interaction between the radiation and the interstellar matter imprints specific absorption features on the X-ray spectrum. We study them with the aim of defining the chemical composition, the crystallinity, and structure of the dust grains that populate the inner regions of the Galaxy. Methods. We investigated the magnesium and the silicon K-edges detected in the Chandra /HETG spectra of eight bright X-ray binaries, distributed in the neighbourhood of the Galactic centre. We modelled the two spectral features using accurate extinction cross-sections of silicates, which we measured at the synchrotron facility Soleil, France. Results. Near the Galactic centre, magnesium and silicon show abundances similar to the solar ones and they are highly depleted from the gas phase (δMg > 0.90 and δSi > 0.96). We find that amorphous olivine with a composition of MgFeSiO4 is the most representative compound along all lines of sight according to our fits. The contribution of Mg-rich silicates and quartz is low (less than 10%). On average we observe a percentage of crystalline dust equal to 11%. For the extragalactic source LMC X-1, we find a preference for forsterite, a magnesium-rich olivine. Along this line of sight we also observe an under-abundance of silicon ASi∕ALMC = 0.5 ± 0.2.

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On the apparent lack of Be X-ray binaries with black holes in the galaxy and in the Magellanic Clouds

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310016340 ◽

2010 ◽

Vol 6 (S275) ◽

pp. 329-330

Author(s):

Janusz Ziółkowski ◽

Krzysztof Belczyński

Keyword(s):

Black Holes ◽

Black Hole ◽

Neutron Star ◽

Stellar Population ◽

Magellanic Clouds ◽

Population Synthesis ◽

X Ray ◽

Stellar Population Synthesis ◽

The Galaxy ◽

X Ray Binaries

AbstractIn the Galaxy there are 67 Be X-ray binaries known to-date. Out of those, 45 host a neutron star, and for the reminder the nature of a companion is not known. None, so far, is known to host a black hole. This disparity is referred to as a missing Be – black hole X-ray binary problem. The stellar population synthesis calculations following the formation of Be X-ray binaries (Belczyński & Ziółkowski 2009) predict that the ratio of the binaries with neutron stars to the ones with black holes is rather high FNS/BH ~ 30–50. A comparison of this ratio with the number of confirmed Be – neutron star X-ray binaries (45) indicates that the expected number of Be – black hole X-ray binaries is of the order of only ~0–2. This is entirely consistent with the observed Galactic sample. Therefore, there is no problem of the missing Be+BH X-Ray Binaries for the GalaxyIn the Magellanic Clouds there are 94 Be X-ray binaries known to-date. Out of those, 60 host a neutron star. Again, none hosts a black hole. The stellar population synthesis calculations carried out specifically for the Magellanic Clouds (Ziółkowski & Belczyński 2010) predict that the ratio of the Be X-ray binaries with neutron stars to the ones with black holes is only FNS/BH ~ 10. This value is rather too low, as it implies the expected number of Be+BH X-ray binaries of the order of ~6, while none is observed. We found, that to remove the discrepancy, one has to take into account a different history of the star formation rate in the Magellanic Clouds, with the respect to the Galaxy. New stellar population synthesis calculations are currently being carried out.

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The Missing Population of Be+Black Hole X-Ray Binaries

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308023302 ◽

2008 ◽

Vol 4 (S252) ◽

pp. 399-403

Author(s):

Aleksander Sadowski ◽

J. Ziółkowski ◽

K. Belczyński ◽

T. Bulik

Keyword(s):

Black Hole ◽

Stellar Population ◽

Magellanic Clouds ◽

Population Synthesis ◽

Period Range ◽

X Ray ◽

Stellar Population Synthesis ◽

The Galaxy ◽

Orbital Periods ◽

X Ray Binaries

AbstractAt present, 117 Be/neutron star (Be/NS) X-ray binaries (XRBs) are known in the Galaxy and the Magellanic Clouds, but not a single Be/black hole (Be/BH) binary was found so far. We carried out the calculations of stellar population synthesis to investigate the case of the apparently missing population of Be/BH XRBs. According to our calculations, the main reason of this disparity is the fact that within the orbital period range where Be XRBs are found (~10 to ~300 days), these systems are formed predominantly with a NS component. The systems with a BH component are formed predominantly with much longer orbital periods and they are not easy to detect.

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Theory of Magnetic-Field Turbulence in Disk Plasmas and Its Application to the Galaxy and Accretion Model of Compact X-Ray Binaries

Plasma Physics ◽

10.1007/978-1-4757-1571-2_18 ◽

1977 ◽

pp. 262-283

Author(s):

Setsuo Ichimaru

Keyword(s):

Magnetic Field ◽

X Ray ◽

Accretion Model ◽

The Galaxy ◽

Magnetic Field Turbulence ◽

X Ray Binaries

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Symbiotic X-ray binaries systems in the galaxy

Astronomy Letters ◽

10.1134/s1063773715040064 ◽

2015 ◽

Vol 41 (3-4) ◽

pp. 114-127 ◽

Cited By ~ 6

Author(s):

A. G. Kuranov ◽

K. A. Postnov

Keyword(s):

X Ray ◽

The Galaxy ◽

X Ray Binaries

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Constraining Progenitors of Observed Low-mass X-ray Binaries Using Convection and Rotation-Boosted Magnetic Braking

The Astrophysical Journal ◽

10.3847/1538-4357/ac236c ◽

2021 ◽

Vol 922 (2) ◽

pp. 174

Author(s):

Kenny X. Van ◽

Natalia Ivanova

Keyword(s):

Mass Transfer ◽

Binary Systems ◽

Formation Rate ◽

Mass Transfer Rate ◽

Population Synthesis ◽

X Ray ◽

Synthesis Technique ◽

Low Mass ◽

Magnetic Braking ◽

X Ray Binaries

Abstract We present a new method for constraining the mass transfer evolution of low-mass X-ray binaries (LMXBs)—a reverse population synthesis technique. This is done using the detailed 1D stellar evolution code MESA (Modules for Experiments in Stellar Astrophysics) to evolve a high-resolution grid of binary systems spanning a comprehensive range of initial donor masses and orbital periods. We use the recently developed convection and rotation-boosted (CARB) magnetic braking scheme. The CARB magnetic braking scheme is the only magnetic braking prescription capable of reproducing an entire sample of well-studied persistent LMXBs—those with mass ratios, periods, and mass transfer rates that have been observationally determined. Using the reverse population synthesis technique, where we follow any simulated system that successfully reproduces an observed LMXB backward, we have constrained possible progenitors for each observed well-studied persistent LMXB. We also determined that the minimum number of LMXB formations in the Milky Way is 1500 per Gyr if we exclude Cyg X-2. For Cyg X-2, the most likely formation rate is 9000 LMXB Gyr−1. The technique we describe can be applied to any observed LMXB with well-constrained mass ratio, period, and mass transfer rate. With the upcoming GAIA DR3 containing information on binary systems, this technique can be applied to the data release to search for progenitors of observed persistent LMXBs.

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Spectroscopy of Stellar X-ray Sources in the Magellanic Clouds

Symposium - International Astronomical Union ◽

10.1017/s0074180900040419 ◽

1984 ◽

Vol 108 ◽

pp. 305-312

Author(s):

J. B. Hutchings

Keyword(s):

Black Hole ◽

Magellanic Cloud ◽

Active Galaxies ◽

Magellanic Clouds ◽

Dwarf Stars ◽

X Ray ◽

Preliminary Comparison ◽

The Galaxy ◽

Optical Identifications ◽

X Ray Binaries

In the Magellanic Clouds, about 75 candidate stellar X-ray sources have been detected. Most of these positions have now been investigated and optical identifications made for ~ 50%. The majority of sources are foreground dwarf stars or background active galaxies. Detailed investigations exist for 3 SMC sources and 6 LMC sources. It is possible to make a preliminary comparison with the population of galactic X-ray sources. The Magellanic Cloud X-ray binaries have a number of unique or remarkable properties and the most important ones are presented and discussed. These include the most rapid pulsars (SMC X-1, 0538–66), the possible precessing disk in LMC X-4, and the black hole candidates LMC X-3, LMC X-1. The properties of these objects relate to the evolution of stars in the Magellanic Clouds and how it differs from the Galaxy.

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X-ray binaries with neutron stars at different accretion stages

Proceedings of the International Astronomical Union ◽

10.1017/s174392131900125x ◽

2018 ◽

Vol 14 (S346) ◽

pp. 219-227

Author(s):

Konstantin A. Postnov ◽

Alexander G. Kuranov ◽

Lev R. Yungelson

Keyword(s):

Magnetic Fields ◽

Neutron Stars ◽

Orbital Period ◽

Population Synthesis ◽

Circular Orbits ◽

X Ray ◽

Accretion Rates ◽

Supercritical Accretion ◽

Binary Evolution ◽

X Ray Binaries

Abstract. Different accretion regimes onto magnetized NSs in HMXBs are considered: wind-fed supersonic (Bondi) regime at high accretion rates <math/> g s-1, subsonic settling regime at lower <math/> and supercritical disc accretion during Roche lobe overflow. In wind-fed stage, NSs in HMXBs reach equilibrium spin periods P* proportional to binary orbital period Pb. At supercritical accretion stage, the system may appear as a pulsating ULX. Population synthesis of Galactic HMXBs using standard assumptions on the binary evolution and NS formation is presented. Comparison of the model P* – Pb (the Corbet diagram), P* – Lx and Pb – Lx distributions with those for the observed HMXBs (including Be X-ray binaries) and pulsating ULXs suggests the importance of the reduction of P* in non-circular orbits, explaining the location of Be X-ray binaries in the model Corbet diagram, and the universal parameters of pulsating ULXs depending only on the NS magnetic fields.

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The High Mass X-ray binaries in star-forming galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318007627 ◽

2018 ◽

Vol 14 (S346) ◽

pp. 332-336

Author(s):

M. Celeste Artale ◽

Nicola Giacobbo ◽

Michela Mapelli ◽

Paolo Esposito

Keyword(s):

Luminosity Function ◽

High Mass ◽

Population Synthesis ◽

Host Galaxies ◽

X Ray ◽

Star Forming ◽

Star Formation In Galaxies ◽

Binary Evolution ◽

X Ray Binaries ◽

The Universe

AbstractThe high mass X-ray binaries (HMXBs) provide an exciting framework to investigate the evolution of massive stars and the processes behind binary evolution. HMXBs have shown to be good tracers of recent star formation in galaxies and might be important feedback sources at early stages of the Universe. Furthermore, HMXBs are likely the progenitors of gravitational wave sources (BH–BH or BH–NS binaries that may merge producing gravitational waves). In this work, we investigate the nature and properties of HMXB population in star-forming galaxies. We combine the results from the population synthesis model MOBSE (Giacobbo & Mapelli 2018a) together with galaxy catalogs from EAGLE simulation (Schaye et al. 2015). Therefore, this method describes the HMXBs within their host galaxies in a self-consistent way. We compute the X-ray luminosity function (XLF) of HMXBs in star-forming galaxies, showing that this methodology matches the main features of the observed XLF.

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