scholarly journals Luminosity function of high-mass X-ray binaries and anisotropy in the distribution of active galactic nuclei toward the Large Magellanic Cloud

2012 ◽  
Vol 38 (8) ◽  
pp. 492-496 ◽  
Author(s):  
A. A. Lutovinov ◽  
S.A. Grebenev ◽  
S. S. Tsygankov
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
Galactic Nuclei ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
High Mass ◽  
X Ray ◽  
X Ray Binaries

Vertical distribution of HMXBs in NGC 55: constraining their centre-of-mass velocity

2020 ◽  
Vol 493 (4) ◽  
pp. 5369-5381 ◽  
Author(s):  
Babis Politakis ◽  
Andreas Zezas ◽  
Jeff J Andrews ◽  
Stephen J Williams
Keyword(s):  
Vertical Distribution ◽  
Compact Object ◽  
Supernova Explosion ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
High Mass ◽  
Centre Of Mass ◽  
X Ray ◽  
X Ray Binaries ◽  
The Vertical Distribution

ABSTRACT We analyse the vertical distribution of high-mass X-ray binaries (HMXBs) in NGC 55, the nearest edge-on galaxy to the Milky Way (MW), based on X-ray observations by Chandra. Adopting a statistical approach, we estimate the difference between the scale height of the vertical distribution of HMXBs and the vertical distribution of star-forming activity between 0.33 and 0.57 kpc. The spatial offsets can be explained by a momentum kick the X-ray binaries receive during the formation of the compact object after a supernova explosion of the primary star. Determining the vertical distribution of HMXBs in the MW using Gaia DR2 astrometry, we find that the corresponding difference is considerably lower at 0.036 ± 0.003 kpc, attributed to the greater gravitational potential of the MW. We also calculate the centre-of-mass transverse velocities of HMXBs in NGC 55, using traveltime information from binary population synthesis codes and for different star formation histories (SFHs). For a flat SFH model (typical of spiral galaxies like NGC 55), we find that HMXBs are moving with a typical transverse velocity between 34 and 48 km s−1, consistent with space velocities of MW HMXBs. For an exponentially declining SFH model, HMXBs are moving at a velocity of 21 km s−1, consistent with the corresponding velocity of HMXBs in the Small Magellanic Cloud and Large Magellanic Cloud. Finally, we estimate the formation efficiency of HMXBs in NGC 55 at 299$_{-46}^{+50}$ (systems/M⊙ yr−1), consistent within the errors with the Magellanic Clouds but significantly higher than the MW, a difference that can be explained by the subsolar metallicity of NGC 55.

scholarly journals X-rays from Green Pea analogues

2017 ◽  
Vol 470 (1) ◽  
pp. 606-611 ◽  
Author(s):  
M. Brorby ◽  
P. Kaaret
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
High Mass ◽  
X Rays ◽  
X Ray ◽  
Star Forming ◽  
Green Pea ◽  
X Ray Binaries

Abstract X-ray observations of two metal-deficient luminous compact galaxies (LCG; SHOC 486 and SDSS J084220.94+115000.2) with properties similar to the so-called Green Pea galaxies were obtained using the Chandra X-ray Observatory. Green Pea galaxies are relatively small, compact (a few kpc across) galaxies that get their green colour from strong [O iii] λ5007 Å emission, an indicator of intense, recent star formation. These two galaxies were predicted to have the highest observed count rates, using the X-ray luminosity–star formation rate (LX–SFR) relation for X-ray binaries, from a statistically complete sample drawn from optical criteria. We determine the X-ray luminosity relative to SFR and metallicity for these two galaxies. Neither exhibits any evidence of active galactic nuclei, and we suspect that the X-ray emission originates from unresolved populations of high-mass X-ray binaries. We discuss the LX–SFR–metallicity plane for star-forming galaxies and show that the two LCGs are consistent with the prediction of this relation. This is the first detection of Green Pea analogues in X-rays.

Polarization Variability of Active Galactic Nuclei and X‐Ray Binaries

1997 ◽  
Vol 487 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Gang Bao ◽  
Petr Hadrava ◽  
Paul J. Wiita ◽  
Ying Xiong
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
X Ray Binaries

scholarly journals Radiative efficiency of hot accretion flow and the radio/X-ray correlation in X-ray binaries

2014 ◽  
Vol 10 (S312) ◽  
pp. 139-140
Author(s):  
Fu-Guo Xie
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Rate ◽  
Galactic Nuclei ◽  
X Ray ◽  
Radiative Efficiency ◽  
Accretion Flow ◽  
Accretion Rates ◽  
Distinctive Property ◽  
X Ray Binaries

AbstractSignificant progresses have been made since the discovery of hot accretion flow, a theory successfully applied to the low-luminosity active galactic nuclei (LLAGNs) and black hole (BH) X-ray binaries (BHBs) in their hard states. Motivated by these updates, we re-investigate the radiative efficiency of hot accretion flow. We find that, the brightest regime of hot accretion flow shows a distinctive property, i.e. it has a constant efficiency independent of accretion rates, similar to the standard thin disk. For less bright regime, the efficiency has a steep positive correlation with the accretion rate, while for faint regime typical of advection-dominated accretion flow, the correlation is shadower. This result can naturally explain the observed two distinctive correlations between radio and X-ray luminosities in black hole X-ray binaries. The key difference in systems with distinctive correlations could be the viscous parameter, which determines the critical luminosity of different accretion modes.

Commission N°48: High Energy Astrophysics (Astrophysique Des Hautes Energies)

1988 ◽  
Vol 20 (1) ◽  
pp. 671-675
Author(s):  
C.J. Cesarsky ◽  
R.A. Sunyaev ◽  
G.W. Clark ◽  
R. Giacconi ◽  
Vin-Yue Qu ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Supernova Remnants ◽  
Cataclysmic Variables ◽  
Galactic Nuclei ◽  
High Energy ◽  
Clusters Of Galaxies ◽  
High Energy Astrophysics ◽  
X Ray ◽  
X Ray Binaries ◽  
Imaging Telescopes

The european X-ray observatory (EXOSAT), which was launched in 1983 and which finished operations in April 1986, has brought a rich harvest of results in the period 1984-1987, surveyed here. The EXOSAT payload consisted of three sets of instruments: two low energy imaging telescopes (LE:E<2 KeV), a medium-energy experiment (ME:E=l-50KeV) and a gas scintillation proportional counter (GSPC:E=2-20KeV). Over most of the energy range covered, EXOSAT was not more sensitive than its predecessor, the american EINSTEIN satellite. But the EINSTEIN satellite is far from having exhausted the treasures of the X-ray sky. And EXOSAT, thanks to its elliptical 90-hour orbit, had the extra advantage of being able to make long, continuous observations of interesting objects, lasting up to 72 hours. Thus, EXOSAT was very well suited for variability studies, and many of its most important findings are in this area. EXOSAT observations sample a vide range of astrophysical sources: X-ray binaries, cataclysmic variables and active stars; supernova remnants and the interstellar medium; active galactic nuclei, and clusters of galaxies. Among the highlights, let us mention:

scholarly journals Theory of Accretion Disk Coronae

1990 ◽  
Vol 115 ◽  
pp. 187-196
Author(s):  
T. R. Kallman
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Cataclysmic Variables ◽  
Galactic Nuclei ◽  
X Ray ◽  
Spectral Signatures ◽  
Low Mass ◽  
X Ray Absorption ◽  
X Ray Binaries ◽  
Theoretical Issues

AbstractAccretion disk coronae are likely to be the dominant site for X-ray absorption and reprocessed emission in low mass X-ray binaries, and may be present in other classes of compact X-ray sources such as active galactic nuclei and cataclysmic variables. In spite of this fact, and in spite of the observational evidence for their existence, there remain many uncertainties about the structure of accretion disk coronae. This paper will discuss the coronal structure and dynamics, their X-ray spectral signatures including coupling to the variability behavior of compact X-ray sources, and the major unsolved theoretical issues surrounding them.

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

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.

scholarly journals Non-equilibrium chemistry and destruction of CO by X-ray flares

2019 ◽  
Vol 486 (1) ◽  
pp. 1094-1122 ◽  
Author(s):  
Jonathan Mackey ◽  
Stefanie Walch ◽  
Daniel Seifried ◽  
Simon C O Glover ◽  
Richard Wünsch ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Thermal Evolution ◽  
Galactic Nuclei ◽  
Galactic Centre ◽  
X Rays ◽  
X Ray ◽  
Uv Emission ◽  
Sgr A ◽  
X Ray Binaries ◽  
Fractal Cloud

ABSTRACT Sources of X-rays such as active galactic nuclei and X-ray binaries are often variable by orders of magnitude in luminosity over time-scales of years. During and after these flares the surrounding gas is out of chemical and thermal equilibrium. We introduce a new implementation of X-ray radiative transfer coupled to a time-dependent chemical network for use in 3D magnetohydrodynamical simulations. A static fractal molecular cloud is irradiated with X-rays of different intensity, and the chemical and thermal evolution of the cloud are studied. For a simulated $10^5\, \mathrm{M}_\odot$ fractal cloud, an X-ray flux &lt;0.01 erg cm−2 s−1 allows the cloud to remain molecular, whereas most of the CO and H2 are destroyed for a flux of ≥1 erg cm−2 s−1. The effects of an X-ray flare, which suddenly increases the X-ray flux by 105×, are then studied. A cloud exposed to a bright flare has 99 per cent of its CO destroyed in 10–20 yr, whereas it takes &gt;103 yr for 99 per cent of the H2 to be destroyed. CO is primarily destroyed by locally generated far-UV emission from collisions between non-thermal electrons and H2; He+ only becomes an important destruction agent when the CO abundance is already very small. After the flare is over, CO re-forms and approaches its equilibrium abundance after 103–105 yr. This implies that molecular clouds close to Sgr A⋆ in the Galactic Centre may still be out of chemical equilibrium, and we predict the existence of clouds near flaring X-ray sources in which CO has been mostly destroyed but H is fully molecular.

scholarly journals Effects of metallicity on high-mass X-ray binary formation

2019 ◽  
Vol 491 (3) ◽  
pp. 3606-3612 ◽  
Author(s):  
S Ponnada ◽  
M Brorby ◽  
P Kaaret
Keyword(s):  
Luminosity Function ◽  
Statistical Significance ◽  
Formation Rate ◽  
High Mass ◽  
X Ray ◽  
Binary Formation ◽  
Different Types ◽  
Solar Metallicity ◽  
Low Metallicity ◽  
X Ray Binaries

ABSTRACT The heating of the intergalactic medium in the early, metal-poor Universe may have been partly due to radiation from high-mass X-ray binaries (HMXBs). Previous investigations on the effect of metallicity have used galaxies of different types. To isolate the effects of metallicity on the production of HMXBs, we study a sample consisting only of 46 blue compact dwarf galaxies covering metallicity in the range 12+log(O/H) of 7.15–8.66. To test the hypothesis of metallicity dependence in the X-ray luminosity function (XLF), we fix the XLF form to that found for near-solar metallicity galaxies and use a Bayesian method to constrain the XLF normalization as a function of star formation rate for three different metallicity ranges in our sample. We find an increase by a factor of 4.45 ± 2.04 in the XLF normalization between the metallicity ranges 7.1–7.7 and 8.2–8.66 at a statistical significance of 99.79 per cent. Our results suggest that HMXB production is enhanced at low metallicity, and consequently that HMXBs may have contributed significantly to the reheating of the early Universe.

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