Статті в журналах: "Galactic binaries"

1

Christiansen, Hugo R. "Neutrino signals from galactic binaries." Brazilian Journal of Physics 37, no. 2b (July 2007): 642–47. http://dx.doi.org/10.1590/s0103-97332007000400031.

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2

Belczynski, Krzysztof, and Ronald E. Taam. "Galactic Populations of Ultracompact Binaries." Astrophysical Journal 603, no. 2 (March 10, 2004): 690–96. http://dx.doi.org/10.1086/381491.

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3

Cornish, Neil J., and Edward K. Porter. "Detecting galactic binaries with LISA." Classical and Quantum Gravity 22, no. 18 (August 24, 2005): S927—S933. http://dx.doi.org/10.1088/0264-9381/22/18/s06.

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4

Bonanos, Alceste Z. "Massive extragalactic eclipsing binaries." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 198. http://dx.doi.org/10.1017/s1743921307010113.

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Masses, radii and luminosities of distant stars can only be measured accurately in eclipsing binaries. The most massive eclipsing binary currently known is WR 20a, which consists of two ~ 80 M⊙ stars in a 3.7 d orbit. Analogs of WR 20a are bound to exist both in massive stellar clusters in our Galaxy and in nearby galaxies. The nearest ones are located in the clusters near the Galactic Center: the Center, Arches, and Quintuplet clusters. The severe amount of reddening in the galactic disk makes the study of galactic clusters challenging. However, with current 8-m class telescopes, the study of massive stars in nearby galaxies is also feasible. The nearest Local Group galaxies (LMC, SMC, M 31, M 33) provide the perfect laboratory for studying massive stars and determining their properties as a function of metallicity. Such studies will constrain models, confirm the dependence of evolution on metallicity and help understand the rate and nature of supernovae and gamma-ray bursts.

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5

Witt, H. J., and S. Mao. "Microlensing With Binaries And Planets." Symposium - International Astronomical Union 173 (1996): 233–34. http://dx.doi.org/10.1017/s0074180900231379.

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The ongoing microlensing experiments have now discovered more than 70 candidate events (Alcock et al. 1993, Bennett et al. 1994, Aubourg et al. 1993, Udalski et al. 1994). These experiments have put important constraints on the dark matter content of the Galactic halo (Alcock et al. 1995a) and yielded many interesting results about Galactic structure (Paczyński et al. 1994, Stanek et al. 1994).

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6

van der Hucht, Karel A., and Bambang Hidayat. "Wolf-Rayet Binaries." Symposium - International Astronomical Union 200 (2001): 79–83. http://dx.doi.org/10.1017/s0074180900225084.

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A WR binary frequency of 37% is found in the VIIth Catalogue of Galactic Wolf-Rayet Stars. Indications are that perhaps all WR stars are binaries and thus that all WR stars point to massive binary formation regions.

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7

Di Stefano, Rosanne. "Microlensing: A Tool to Probe Distant Binary Populations." Symposium - International Astronomical Union 200 (2001): 529–38. http://dx.doi.org/10.1017/s0074180900225643.

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Programs designed to observe gravitational microlensing are poised to provide a great deal of information about binary populations far from Earth, including those in the Galactic Bulge, in the Magellanic Clouds, in M31, and perhaps in other external galaxies. Because many millions of stars are monitored, microlensing observations allow us to study binaries in three ways: (1) when they are “involved” in a microlensing event (as either a lens or lensed source), (2) when variability due to binarity produces significant variations in the light curve, and (3) when light from a more distant star is attenuated or refracted by matter associated with the binary system (e.g., in a disk).Microlensing observations will discover large numbers of binaries and planetary systems in a variety of galactic environments. Thus, comparative statistical studies of binary properties (distributions of mass ratios and orbital separations) are possible.An intriguing sign that we have already begun to learn about binaries through microlensing observations comes from work indicating that all of the lenses detected to date may in fact be binaries. For observations along the direction of the Magellanic Clouds this would imply that, if the lenses are primarily located in the Halo, then MACHOs tend to be binaries. If, on the other hand, most of the lenses are located in the Magellanic Clouds, microlensing observations are giving us a unique way to explore a distant stellar population of binaries.

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8

Stroeer, Alexander, Matthew Benacquista, and Frank Ceballos. "Detecting Double Degenerate Progenitors of SNe Ia with LISA." Proceedings of the International Astronomical Union 7, S281 (July 2011): 217–20. http://dx.doi.org/10.1017/s1743921312015062.

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AbstractThe Galactic population of close white dwarf binaries is expected to provide the largest number of gravitational wave sources for low frequency detectors such as the Laser Interferometer Space Antenna (LISA). Current data analysis techniques have demonstrated the capability of resolving on the order of 104 white dwarf binaries from a 2 year observation. Resolved binaries are either at high frequencies or large amplitudes. Such systems are more likely to be high-mass binaries, a subset of which will be progenitors of SNe Ia in the double degenerate scenario. We report on results of a study of the properties of resolved binaries using a population synthesis model of the Galactic white dwarf binaries and a LISA data analysis algorithm using Mock LISA Data Challenge tools.

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9

Zwitter, Tomaž. "GAIA Survey of Galactic Eclipsing Binaries." International Astronomical Union Colloquium 187 (2002): 31–36. http://dx.doi.org/10.1017/s0252921100001196.

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AbstractThe general importance and capabilities of observations of eclipsing binaries by the forthcoming ESA mission GAIA are discussed. Availability of spectroscopic observations and a large number of photometric bands on board will make it possible to reliably determine physical parameters for ∼ 105 binary stars. It is stressed that current methods of object by object analysis will have to be modified and included in an automatic analysis pipeline.

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10

Hoang, Bao-Minh, Smadar Naoz, and Melodie Sloneker. "Binary Natal Kicks in the Galactic Center: X-Ray Binaries, Hypervelocity Stars, and Gravitational Waves." Astrophysical Journal 934, no. 1 (July 1, 2022): 54. http://dx.doi.org/10.3847/1538-4357/ac7787.

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Abstract Theoretical and observational studies suggest that stellar binaries exist in large numbers in galactic nuclei like our own Galactic Center. Neutron stars (NSs), and debatedly, black holes and white dwarfs, receive natal kicks at birth. In this work, we study the effect of two successive natal kicks on a population of stellar binaries orbiting the massive black hole (MBH) in our Galactic Center. These natal kicks can significantly alter the binary orbit in a variety of ways, and also the orbit of the binary around the MBH. We found a variety of dynamical outcomes resulting from these kicks, including a steeper cusp of single NSs relative to the initial binary distribution. Furthermore, hypervelocity star and binary candidates, including hypervelocity X-ray binaries, are a common outcome of natal kicks. In addition, we show that the population of X-ray binaries in the Galactic Center can be used as a diagnostic for the BH natal kick distribution. Finally, we estimate the rate of gravitational wave events triggered by natal kicks, including binary mergers and EMRIs.

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11

Chanamé, Julio. "Catalogs of Wide Binaries: Impact on Galactic Astronomy." Proceedings of the International Astronomical Union 2, S240 (August 2006): 316–25. http://dx.doi.org/10.1017/s1743921307004243.

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AbstractWide binaries, particularly in large numbers and as free from selection biases as possible, constitute a largely overlooked tool for studying the Galaxy. The goal of this review is to highlight the potential inherent to large samples of field wide binaries for research on problems as varied as star formation in the early Galaxy, the nature of halo dark matter, the evolution of the stellar halo, new geometric distances, metallicities, masses, and ages of field stars and white dwarfs, and much more. Using the Revised NLTT as an illustrative example, I review the main steps in the assembly of a large catalog of wide binaries useful for multiple applications. The capability of cleanly separating between the Galactic disk and halo populations using good colors and proper motions is emphasized. The critical role of large surveys for research on wide binaries as well as for the better understanding of the Galaxy in general is stressed throughout. Finally, I point out the potential for assembling new samples of wide binaries from available proper-motion surveys, and report on current efforts of using the SDSS towards this goal.

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12

Blelly, Aurore, Jérôme Bobin, and Hervé Moutarde. "Sparse data inpainting for the recovery of Galactic-binary gravitational wave signals from gapped data." Monthly Notices of the Royal Astronomical Society 509, no. 4 (November 18, 2021): 5902–17. http://dx.doi.org/10.1093/mnras/stab3314.

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ABSTRACT The forthcoming space-based gravitational wave observatory LISA will open a new window for the measurement of Galactic binaries, which will deliver unprecedented information about these systems. However, the detection of Galactic binary gravitational wave signals is challenged by the presence of gaps in the data. Whether being planned or not, gapped data reduce our ability to detect faint signals and increase the risk of misdetection. Inspired by advances in signal processing, we introduce a non-parametric inpainting algorithm based on the sparse representation of the Galactic binary signal in the Fourier domain. In contrast to traditional inpainting approaches, noise statistics are known theoretically on ungapped measurements only. This calls for the joint recovery of both the ungapped noise and the Galactic binary signal. We thoroughly show that sparse inpainting yields an accurate estimation of the gravitational imprint of the Galactic binaries. Additionally, we highlight that the proposed algorithm produces a statistically consistent ungapped noise estimate. We further evaluate the performances of the proposed inpainting methods to recover the gravitational wave signal on a simple example involving verification Galactic binaries recently proposed in LISA data challenges.

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13

Verbunt, Frank. "The Formation and Evolution of Binaries in Globular Clusters." Highlights of Astronomy 8 (1989): 139–42. http://dx.doi.org/10.1017/s1539299600007632.

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AbstractThe number density of stars in the cores of globular clusters is high enough for close encounters between stars to be frequent. These encounters may lead to the formation of binaries. Those binaries which do not easily form via the evolution of primordial main-sequence star binaries, and are therefore rare in the galactic disk, can be common in globular clusters. Examples of such binaries are the low-mass X-ray binaries. Such binaries may evolve into radiopulsars.

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14

Vos, J., A. Bobrick, and M. Vučković. "Observed binary populations reflect the Galactic history." Astronomy & Astrophysics 641 (September 2020): A163. http://dx.doi.org/10.1051/0004-6361/201937195.

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Context. Wide hot subdwarf B (sdB) binaries with main-sequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this correlation have, so far, been lacking a conclusive explanation. Aims. We aim to find a binary evolution model which can explain the observed correlation. Methods. Radii of evolved red giants, and hence the resulting orbital periods, strongly depend on their metallicity. We performed a small but statistically significant binary population synthesis study with the binary stellar evolution code MESA. We used a standard model for binary mass loss and a standard metallicity history of the Galaxy. The resulting sdB systems were selected based on the same criteria as was used in observations and then compared with the observed population. Results. We have achieved an excellent match to the observed period-mass ratio correlation without explicitly fine-tuning any parameters. Furthermore, our models produce a very good match to the observed period-metallicity correlation. We predict several new correlations, which link the observed sdB binaries to their progenitors, and a correlation between the orbital period, metallicity, and core mass for subdwarfs and young low-mass helium white dwarfs. We also predict that sdB binaries have distinct orbital properties depending on whether they formed in the Galactic bulge, thin or thick disc, or the halo. Conclusions. We demonstrate, for the first time, how the metallicity history of the Milky Way is imprinted in the properties of the observed post-mass transfer binaries. We show that Galactic chemical evolution is an important factor in binary population studies of interacting systems containing at least one evolved low-mass (Minit < 1.6 M⊙) component. Finally, we provide an observationally supported model of mass transfer from low-mass red giants onto main-sequence stars.

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15

Yungelson, L., A. Tutukov, A. Fedorova, M. Livio, and J. W. Truran. "A Model for the Galactic Population of Supersoft X-Ray Sources." International Astronomical Union Colloquium 158 (1996): 417–20. http://dx.doi.org/10.1017/s0252921100039282.

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AbstractThree major sub-populations of Galactic supersoft X-ray sources may exist: semi-detached binaries with main sequence or subgiant donors, and symbiotic binaries (~550, ~460, and ~600 objects, respectively). Each group contains both permanent and transient sources. The intrinsic and interstellar absorptions reduce the number of observable sources to ~25. We derive the distributions of the sources over orbital periods, masses of the components, and ‘on’-times. The rate at which white dwarfs in Galactic binaries reach MCh is ~ 3 10−5 yr−1. The rate of He-shell detonations which may lead to supernovae may be up to 3 10−4 yr−1.

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16

Li, Gongjie, Idan Ginsburg, Smadar Naoz, and Abraham Loeb. "Eclipsing Stellar Binaries in the Galactic Center." Astrophysical Journal 851, no. 2 (December 20, 2017): 131. http://dx.doi.org/10.3847/1538-4357/aa9ce7.

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17

Borodina, Olga I., Anton F. Seleznev, Giovanni Carraro, and Vladimir M. Danilov. "Unresolved Binaries and Galactic Clusters’ Mass Estimates." Astrophysical Journal 874, no. 2 (March 29, 2019): 127. http://dx.doi.org/10.3847/1538-4357/ab08e5.

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18

Kandrup, Henry E., Ioannis V. Sideris, Balša Terzić, and Courtlandt L. Bohn. "Supermassive Black Hole Binaries as Galactic Blenders." Astrophysical Journal 597, no. 1 (November 2003): 111–30. http://dx.doi.org/10.1086/378287.

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19

Nissanke, Samaya, Michele Vallisneri, Gijs Nelemans, and Thomas A. Prince. "GRAVITATIONAL-WAVE EMISSION FROM COMPACT GALACTIC BINARIES." Astrophysical Journal 758, no. 2 (October 9, 2012): 131. http://dx.doi.org/10.1088/0004-637x/758/2/131.

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20

Cartwright, T. F., M. C. Engel, C. O. Heinke, G. R. Sivakoff, J. J. Berger, J. C. Gladstone, and N. Ivanova. "GALACTIC ULTRACOMPACT X-RAY BINARIES: EMPIRICAL LUMINOSITIES." Astrophysical Journal 768, no. 2 (April 26, 2013): 183. http://dx.doi.org/10.1088/0004-637x/768/2/183.

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21

Griffin, R. F. "Spectroscopic binaries near the north galactic pole." Journal of Astrophysics and Astronomy 6, no. 1 (March 1985): 71–73. http://dx.doi.org/10.1007/bf02719531.

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22

Griffin, R. F. "Spectroscopic binaries near the north galactic pole." Journal of Astrophysics and Astronomy 6, no. 3 (September 1985): 159–64. http://dx.doi.org/10.1007/bf02714996.

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23

Griffin, R. F. "Spectroscopic binaries near the North Galactic pole." Journal of Astrophysics and Astronomy 6, no. 2 (June 1985): 77–83. http://dx.doi.org/10.1007/bf02715079.

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24

Griffin, R. F. "Spectroscopic binaries near the north galactic pole." Journal of Astrophysics and Astronomy 12, no. 3 (September 1991): 265–68. http://dx.doi.org/10.1007/bf02702881.

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25

Griffin, R. F., and J. J. Eitter. "Spectroscopic binaries near the North Galactic Pole." Journal of Astrophysics and Astronomy 13, no. 2 (June 1992): 209–16. http://dx.doi.org/10.1007/bf02702311.

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26

Griffin, R. F., and D. W. Beggs. "Spectroscopic binaries near the north Galactic Pole." Journal of Astrophysics and Astronomy 12, no. 4 (December 1991): 289–310. http://dx.doi.org/10.1007/bf02702318.

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27

Baruteau, C., J. Cuadra, and D. N. C. Lin. "BINARIES MIGRATING IN A GASEOUS DISK: WHERE ARE THE GALACTIC CENTER BINARIES?" Astrophysical Journal 726, no. 1 (December 10, 2010): 28. http://dx.doi.org/10.1088/0004-637x/726/1/28.

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28

Sberna, Laura, Alexandre Toubiana, and M. Coleman Miller. "Golden Galactic Binaries for LISA: Mass-transferring White Dwarf Black Hole Binaries." Astrophysical Journal 908, no. 1 (February 1, 2021): 1. http://dx.doi.org/10.3847/1538-4357/abccc7.

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29

Chornay, Nicholas, and Nicholas A. Walton. "New Close Binary Central Stars of Planetary Nebulae from Gaia DR3 Epoch Photometry." Research Notes of the AAS 6, no. 9 (September 5, 2022): 177. http://dx.doi.org/10.3847/2515-5172/ac8e6c.

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Abstract Close binary interactions perform a key role in the formation and shaping of planetary nebulae (PNe). However only a small fraction of Galactic PNe are known to host close binary systems. Many such systems are detectable through photometric variability. We searched recently published epoch photometry data from Gaia DR3 for planetary nebula central stars with periodic photometric variability indicative of binarity, uncovering four previously unknown close binaries.

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30

Hwang, Hsiang-Chih, and Nadia L. Zakamska. "Lifetime of short-period binaries measured from their Galactic kinematics." Monthly Notices of the Royal Astronomical Society 493, no. 2 (February 12, 2020): 2271–86. http://dx.doi.org/10.1093/mnras/staa400.

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ABSTRACT As a significant fraction of stars are in multiple systems, binaries play a crucial role in stellar evolution. Among short-period (<1 d) binary characteristics, age remains one of the most difficult to measure. In this paper, we constrain the lifetime of short-period binaries through their kinematics. With the kinematic information from Gaia Data Release 2 and light curves from Wide-field Infrared Survey Explorer (WISE), we investigate the eclipsing binary fraction as a function of kinematics for a volume-limited main-sequence sample. We find that the eclipsing binary fraction peaks at a tangential velocity of 101.3−1.6 km s−1, and decreases towards both low- and high-velocity end. This implies that thick disc and halo stars have eclipsing binary fraction ≳10 times smaller than the thin-disc stars. This is further supported by the dependence of eclipsing binary fraction on the Galactic latitude. Using Galactic models, we show that our results are inconsistent with any known dependence of binary fraction on metallicity. Instead, our best-fitting models suggest that the formation of these short-period binaries is delayed by 0.6–3 Gyr, and the disappearing time is less than the age of the thick disc. The delayed formation time of ≳0.6 Gyr implies that these short-period main-sequence binaries cannot be formed by pre-main sequence interaction and the Kozai–Lidov mechanism alone, and suggests that magnetic braking plays a key role in their formation. Because the main-sequence lifetime of our sample is longer than 14 Gyr, if the disappearance of short-period binaries in the old population is due to their finite lifetime, our results imply that most (≳90 per cent) short-period binaries in our sample merge during their main-sequence stage.

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31

PAREDES, J. M. "VHE GAMMA-RAYS FROM GALACTIC X-RAY BINARY SYSTEMS." International Journal of Modern Physics D 17, no. 10 (September 2008): 1849–58. http://dx.doi.org/10.1142/s0218271808013480.

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The detection of TeV gamma-rays from LS 5039 and the binary pulsar PSR B1259–63 by HESS, and from LS I +61 303 and the stellar-mass black hole Cygnus X-1 by MAGIC, provides clear evidence of very efficient acceleration of particles to multi-TeV energies in X-ray binaries. These observations demonstrate the richness of nonthermal phenomena in compact galactic objects containing relativistic outflows or winds produced near black holes and neutron stars. I review here some of the main observational results on very high energy (VHE) γ-ray emission from X-ray binaries, as well as some of the proposed scenarios to explain the production of VHE γ-rays. I put special emphasis on the flare TeV emission, suggesting that the flaring activity might be a common phenomena in X-ray binaries.

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32

Wu, You, Xuefei Chen, Hailiang Chen, Zhenwei Li, and Zhanwen Han. "Hot subdwarf B stars with neutron star components." Astronomy & Astrophysics 634 (February 2020): A126. http://dx.doi.org/10.1051/0004-6361/201935792.

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Context. Subdwarf B stars (sdBs) play a crucial role in stellar evolution, asteroseismology, and far-UV radiation of early-type galaxies, and have been intensively studied with observation and theory. It has theoretically been predicted that sdBs with neutron star (NS) companions exist in the Galaxy, but none have been discovered yet. This remains a puzzle in this field. In a previous study (hereafter Paper I), we have studied the formation channels of sdB+NS binaries from main-sequence (MS) stars plus NS binaries by establishing a model grid, but it is still unclear how these binaries consisting of MS stars and NS binaries came to be in the first place. Aims. We systematically study the formation of sdB+NS binaries from their original zero-age main-sequence progenitors. We bridge the gap left by our previous study in this way. We obtain the statistical population properties of sdB+NS binaries and provide some guidance for observational efforts. Methods. We first used Hurley’s rapid binary evolution code BSE to evolve 107 primordial binaries to the point where the companions of NS+MS, NS+Hertzsprung gap star, and NS+Giant Branch star binaries have just filled their Roche lobes. Next, we injected these binaries into the model grid we developed in Paper I to obtain the properties of the sdB+NS populations. We adopted two prescriptions of NS natal kicks: the classical Maxwellian distribution with a dispersion of σ = 265 km s−1, and a linear formula that assumes that the kick velocity is associated with the ratio of ejected to remnant mass. Different values of αCE, where αCE is the common-envelope ejection efficiency, were chosen to examine the effect of common-envelope evolution on the results. Results. In the Galaxy, the birthrate of sdB+NS binaries is about 10−4 yr−1 and there are ∼7000 − 21 000 such binaries. This contributes 0.3−0.5% of all sdB binaries in the most favorable case. Most Galactic sdB+NS binaries (≳60%) arise from the channel of stable mass transfer. The value of αCE has little effect on the results, but when we use the linear formula prescription of NS natal kick, the number and birthrate doubles in comparison to the results we obtained with the Maxwellian distribution. The orbital periods of sdB+NS binaries from different formation channels differ significantly, as expected. This results in two peaks in the radial velocity (RV) semi-amplitude distribution: 100 − 150 km s−1 for stable mass transfer, and 400 − 600 km s−1 for common-envelope ejection. However, the two sdB+NS binary populations exhibit similar delay-time distributions, which both peak at about 0.2 Gyr. This indicates that Galactic sdB+NS binaries are born in very young populations, probably in the Galactic disk. The sdB+NS binaries produced from the common-envelope ejection channel are potential sources of strong gravitational wave radiation (GWR), and about ∼100 − 300 could be detected by the Laser Interferometer Space Antenna (LISA) with a signal-to-noise ratio of 1. Conclusions. Most sdB+NS binaries are located in the Galactic disk with small RV semi-amplitudes. SdB+NS binaries with large RV semi-amplitudes are expected to be strong GWR sources, some of which could be detected by LISA in the future.

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33

Negueruela, Ignacio. "Populations of Massive X-Ray Binaries." International Astronomical Union Colloquium 194 (2004): 55–56. http://dx.doi.org/10.1017/s0252921100151899.

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AbstractThe population of massive X-ray binaries in a galaxy can provide important constraints on its recent history of star formation. However, further knowledge of the Galactic population and formation mechanisms is needed before deeper inferences can be made for other galaxies.

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34

Li, M. C. A., N. J. Rattenbury, I. A. Bond, T. Sumi, D. P. Bennett, N. Koshimoto, F. Abe, et al. "The first eclipsing binary catalogue from the MOA-II data base." Monthly Notices of the Royal Astronomical Society 470, no. 1 (May 23, 2017): 539–50. http://dx.doi.org/10.1093/mnras/stx1280.

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Abstract We present the first catalogue of eclipsing binaries in two MOA (Microlensing Observations in Astrophysics) fields towards the Galactic bulge, in which over 8000 candidates, mostly contact and semidetached binaries of periods <1 d, were identified. In this paper, the light curves of a small number of interesting candidates, including eccentric binaries, binaries with noteworthy phase modulations and eclipsing RS Canum Venaticorum type stars, are shown as examples. In addition, we identified three triple object candidates by detecting the light-travel-time effect in their eclipse time variation curves.

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35

Tanaka, Y. "Recent Ginga Results on Galactic X-Ray Binaries." Highlights of Astronomy 9 (1992): 211–15. http://dx.doi.org/10.1017/s1539299600008947.

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AbstractBased on the recent Ginga results, following topics on X-ray binaries are briefly discussed: The cyclotron resonnance features observed from several X-ray pulsars, and related problem of the magnetic field decay. Search for millisec. pulsations from LMXRBs. Very bright transients which are suspected to be new black hole candidates, and an estimation of the number of such black hole sources in our galaxy.

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36

De Donder, Erwin, and Dany Vanbeveren. "The influence of binaries on galactic chemical evolution." New Astronomy Reviews 48, no. 10 (September 2004): 861–975. http://dx.doi.org/10.1016/j.newar.2004.07.001.

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37

Faucher-Giguère, Claude-André, and Abraham Loeb. "Pulsar-black hole binaries in the Galactic Centre." Monthly Notices of the Royal Astronomical Society 415, no. 4 (June 16, 2011): 3951–61. http://dx.doi.org/10.1111/j.1365-2966.2011.19019.x.

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38

Benacquista, M. J., S. L. Larson, and B. E. Taylor. "Selection effects in resolving Galactic binaries with LISA." Classical and Quantum Gravity 24, no. 19 (September 19, 2007): S513—S520. http://dx.doi.org/10.1088/0264-9381/24/19/s14.

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39

Makino, Junichiro. "11.14. Massive black hole binaries in galactic nuclei." Symposium - International Astronomical Union 184 (1998): 483–84. http://dx.doi.org/10.1017/s0074180900085685.

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Many large ellipticals were believed to have large, flat core, of which the radius is typically a few percents of the effective radius (e.g., Lauer, 1985). However, HST observations (e.g., Lauer et al., 1995) have revealed that they are not flat cores at all. The “cores” observed by HST are actually very shallow central density cusps (ρ ~ r−0.5~–1). Such a shallow cusp poses a serious problem to almost any scenario of the formation of ellipticals. If these ellipticals do not have central black holes (MBHs), we are faced with very strange structure with the velocity dispersion decreasing inward. Neither dissipationless/dissipational collapse nor merging have been able to make such a density distribution.

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40

Amaro-Seoane, Pau, M. Coleman Miller, and Gareth F. Kennedy. "Tidal disruptions of separated binaries in galactic nuclei." Monthly Notices of the Royal Astronomical Society 425, no. 4 (August 30, 2012): 2401–6. http://dx.doi.org/10.1111/j.1365-2966.2012.21162.x.

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41

Bregman, Joel N., Jimmy A. Irwin, Patrick Seitzer, and Matt Flores. "Galactic Globular Clusters with Luminous X‐Ray Binaries." Astrophysical Journal 640, no. 1 (March 20, 2006): 282–87. http://dx.doi.org/10.1086/500037.

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42

Błaut, Arkadiusz. "Parameter estimation accuracies of Galactic binaries with eLISA." Astroparticle Physics 101 (September 2018): 17–26. http://dx.doi.org/10.1016/j.astropartphys.2018.04.001.

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43

Goyal, A. N. "Distribution of astrometric binaries in various galactic latitudes." Astrophysics and Space Science 110, no. 1 (March 1985): 125–31. http://dx.doi.org/10.1007/bf00660616.

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44

Boller, Th. "Supersoft AGNs and their relations to Galactic binaries." Astronomische Nachrichten 331, no. 2 (February 2010): 235–38. http://dx.doi.org/10.1002/asna.200911334.

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45

Kotov, V. A. "A Striking Similarity Between the Sun, Binary Systems and RR Lyrae Stars." International Astronomical Union Colloquium 139 (1993): 160. http://dx.doi.org/10.1017/s0252921100117191.

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AbstractThe periodicity of P0=160.0101 (±1) min discovered in the Sun's global oscillations, then in rapid variability of active galactic nuclei (AGNs) (Kotov & Lyuty 1990), might have a cosmological origin. Analysing the distribution of periods of ∼4000 close binaries we found that the most commensurate (with an odd-even parity taken into account) period of galactic binaries is equal to 160.0(±1) min (∼ 4σ). Accordingly, it is argued that the famous 2-3 hr gap of cataclysmic binaries might be closely associated with the “universal” P0- oscillation. A similar analysis applied to the ∼1200 RR Lyrae variables in galactic globular clusters (GCs) and 72 RR Lyraes in the LMC GCs (Graham 1985; Nemec et al. 1985) showed that for all those stars the P0- period appears to be the most “resonant” one (Fig. 1). This strongly supports the cosmological origin of the P0- oscillation. Since the P0- resonance for RR Lyraes appears to be most pronounced when the “odd-even” parity is taken into account, it is hypothesized that variability in the majority of GC RR Lyraes should be related to their binary nature and may be relevant to explanation of Blazhko effect.

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46

Yungelson, L. R., and A. V. Tutukov. "Statistics of Wolf-Rayet Binaries." Symposium - International Astronomical Union 143 (1991): 459–64. http://dx.doi.org/10.1017/s0074180900045629.

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A theoretical model of the ensemble of galactic Wolf-Rayet stars is constructed, assuming that all of them are members of either close or wide binaries. The model provides a reasonable explanation of the observed number of WR stars, their distribution over masses, mass ratios of components in binary systems, and spatial velocities. It predicts that up to 10 % of the apparently single WR stars have relativistic companions hidden inside thick stellar winds.

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47

Wadiasingh, Zorawar, Alice K. Harding, Christo Venter, Markus Böttcher, and Matthew G. Baring. "MSP Binaries as Astrophysical Laboratories." Proceedings of the International Astronomical Union 13, S337 (September 2017): 420–21. http://dx.doi.org/10.1017/s174392131700905x.

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AbstractFollow-up of unidentified Fermi sources has expanded the number of known galactic-field “black widow” and “redback” millisecond pulsar binaries from four to nearly 30. Several systems observed by Chandra, XMM-Newton, Suzaku, and NuSTAR exhibit double-peaked X-ray orbital modulation. This is attributed to synchrotron emission from electrons accelerated in an intrabinary shock and Doppler boosting by mildly relativistic bulk flow. We briefly discuss the rich complexity of these systems, their astrophysical utility, and open questions.

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48

Trani, Alessandro A. "Do three-body encounters in galactic nuclei affect compact binary merger rates?" Proceedings of the International Astronomical Union 14, S351 (May 2019): 174–77. http://dx.doi.org/10.1017/s174392131900721x.

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AbstractHigh-density cusps of compact remnants are expected to form around supermassive black holes (SMBHs) in galactic nuclei via dynamical friction and two-body relaxation. Due to the high density, binaries in orbit around the SMBH can frequently undergo close encounters with compact remnants from the cusp. This can affect the gravitational wave merger rate of compact binaries in galactic nuclei. We investigated this process by means of high accuracy few-body simulations, performed with a novel Monte Carlo approach. We find that, around a SgrA*-like SMBH, three-body encounters increase the number of mergers by a factor of 3. This occurs because close encounters can reorient binaries with respect to their orbital plane around the SMBH, increasing the number of Kozai-Lidov induced mergers. We obtain a binary black hole merger rate of ГMW = 1.6 × 10−6 yr−1 per Milky Way-like nucleus.

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49

Bartels, R., F. Calore, E. Storm, and C. Weniger. "Galactic binaries can explain the Fermi Galactic centre excess and 511 keV emission." Monthly Notices of the Royal Astronomical Society 480, no. 3 (August 8, 2018): 3826–41. http://dx.doi.org/10.1093/mnras/sty2135.

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50

Fragione, Giacomo, Evgeni Grishin, Nathan W. C. Leigh, Hagai B. Perets, and Rosalba Perna. "Black hole and neutron star mergers in galactic nuclei." Monthly Notices of the Royal Astronomical Society 488, no. 1 (June 13, 2019): 47–63. http://dx.doi.org/10.1093/mnras/stz1651.

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Abstract Nuclear star clusters surrounding supermassive black holes (SMBHs) in galactic nuclei contain large numbers of stars, black holes (BHs), and neutron stars (NSs), a fraction of which are likely to form binaries. These binaries were suggested to form a triple system with the SMBH, which acts as a perturber and may enhance BH and NS mergers via the Lidov–Kozai mechanism. We follow-up previous studies, but for the first time perform an extensive statistical study of BH–BH, NS–NS, and BH–NS binary mergers by means of direct high-precision regularized N-body simulations, including post-Newtonian (PN) terms up to order PN2.5. We consider different SMBH masses, slopes for the BH mass function, binary semimajor axis and eccentricity distributions, and different spatial distributions for the binaries. We find that the merger rates are a decreasing function of the SMBH mass and are in the ranges ∼0.17–0.52, ∼0.06–0.10, and ∼0.04–0.16 Gpc−3 yr−1 for BH–BH, BH–NS, and NS–NS binaries, respectively. However, the rate estimate from this channel remains highly uncertain and depends on the specific assumptions regarding the star formation history in galactic nuclei and the supply rate of compact objects (COs). We find that ${\sim } 10\!-\!20{{\ \rm per\ cent}}$ of the mergers enter the LIGO band with eccentricities ≳0.1. We also compare our results to the secular approximation, and show that N-body simulations generally predict a larger number of mergers. Finally, these events can also be observable via their electromagnetic counterparts, thus making these CO mergers especially valuable for cosmological and astrophysical purposes.

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