source
stringlengths 1
2.05k
⌀ | target
stringlengths 1
11.7k
|
|---|---|
However, attained its maximum after | However, attained its maximum after |
(z20r.) estimated for this object [rom our line energy curves (Figure 2). | $\approx 20r_{\rm g}$ ) estimated for this object from our line energy curves (Figure 2). |
the X-ray spectra of the NLSI Mrk 766 show a broad emission line at zz6.7 keV (Poundsetal.2003). | the X-ray spectra of the NLS1 Mrk 766 show a broad emission line at $\approx 6.7$ keV \citep[]{Pounds2003}. |
. From our plots in Figure 2. we infer that the emission region is located at 35r,ZrX50r, [rom the central DIT. | From our plots in Figure 2, we infer that the emission region is located at $35r_{\rm g} \la r \la 50 r_{\rm g}$ from the central BH. |
1n addition. Turneretal.(2004) found a transient narrow line at 25.6 keV and interpreted it as evidence for blob ejection of neutral or low-ionized material. | In addition, \cite{Turner2004} found a transient narrow line at $\approx 5.6$ keV and interpreted it as evidence for blob ejection of neutral or low-ionized material. |
H£ so. the rest-frame line energy is z6.4 keV. and the line emission region may be located at 50r,SSor100r. corresponding to a distance of ~104 em for a DIE mass of 10 (Zhou )05).. in broad agreement with the results of Turnerctal. (2004).. | If so, the rest-frame line energy is $\approx 6.4$ keV, and the line emission region may be located at $50 r_{\rm g} \la r \la 100 r_{\rm g}$, corresponding to a distance of $\sim 10^{14}$ cm for a BH mass of $10^{6.6}$ \citep[]{Zhou2005}, in broad agreement with the results of \cite{Turner2004}. . |
the spectrum of this NLSI galaxy shows a sharp drop at energies z7 7.5 keV(Bollerctal.2002:Galloetal. 2004b). | the spectrum of this NLS1 galaxy shows a sharp drop at energies $\approx 7$ $7.5$ \citep[]{Boller2002, Gallo2004b}. |
. A partial covering model was introduced. to reduce the need for an extreme iron overabundance (Lanakaetal. 2004). | A partial covering model was introduced to reduce the need for an extreme iron overabundance \citep[]{Tanaka2004}. |
.. Llowever. an alternative possibility is that the X-ray spectrum is dominated: by ionized reflection. rather mn absorption. | However, an alternative possibility is that the X-ray spectrum is dominated by ionized reflection rather than absorption. |
In this scenario. it was argued (Fabianetal.2004) that the two observations support the ight bending model of Miniutti&Fabian.(2004). | In this scenario, it was argued \citep{Fabian2004} that the two observations support the light bending model of \citet[]{Miniutti2004}. |
.. Fabianetal.(2009). also measured a time lag of about 30s between 1e soft energv. band (0.3 1 keV) and the medium energy mand (1 4 keV). | \cite{Fabian2009} also measured a time lag of about 30s between the soft energy band $0.3$ $1$ keV) and the medium energy band $1$ $4$ keV). |
Combining this short time lag with the =neasured width of the broad iron L emission. they suggested jiu the X-ray reverberation comes [from matter very. close o the event horizon of a rapidly spinning DII. | Combining this short time lag with the measured width of the broad iron L emission, they suggested that the X-ray reverberation comes from matter very close to the event horizon of a rapidly spinning BH. |
However. considering a larger energy range (0.3 7.5 keV). Milleretal.(2010) argued instead that the observed time delays extend up to about 18008 in the hard band: this is consistent with reverberation caused by scattering of X-rays passing through much more distant. absorbing material. | However, considering a larger energy range $0.3$ $7.5$ keV), \cite{Miller2010} argued instead that the observed time delays extend up to about 1800s in the hard band; this is consistent with reverberation caused by scattering of X-rays passing through much more distant absorbing material. |
For our adopted mass of LO!" (Zhou&Wang2005).. Agit~ 1. | For our adopted mass of $10^{6.37}$ \citep{Zhou2005}, $\lambda_{\rm Edd} \sim 1$ . |
This suggests that 495 may have a highlv-ionized disk within z50r, for a Schwarzschild BLL. or within z20r. Lor a rapidly spinning DII. | This suggests that $-$ 495 may have a highly-ionized disk within $\approx 50 r_{\rm g}$ for a Schwarzschild BH, or within $\approx 20 r_{\rm g}$ for a rapidly spinning BH. |
In our scenario. those characteristic distances may be the origin of the observed iron lines al rest-[rame energies zz6.5 6.7 keV (Fabianetal.2009:Zoghbietal. 2010). | In our scenario, those characteristic distances may be the origin of the observed iron lines at rest-frame energies $\approx 6.5$ $6.7$ keV \citep[]{Fabian2009, Zoghbi2010}. |
. simultaneous and. observations showed. (Turnerctal.2002). two pairs of weak emission features. including a component at zz6.9 keV. symmetrically located around a strong. narrow 6.4 keV line. | simultaneous and observations showed \citep{Turner2002} two pairs of weak emission features, including a component at $\approx 6.9$ keV, symmetrically located around a strong, narrow 6.4 keV line. |
TFhis structure was interpreted (Purneretal.2002) as evidence for relativistic broadening of disk lines from three different radii. | This structure was interpreted \citep{Turner2002}
as evidence for relativistic broadening of disk lines from three different radii. |
In. our model. we find that. [or Agar~0.01 (Figure 2) even the innermost region of the accretion disk must remain neutral. | In our model, we find that for $\lambda_{\rm Edd} \sim 0.01$ (Figure 2) even the innermost region of the accretion disk must remain neutral. |
Thus. if the observed 6.5 keV and 6.9 keV lines are emitted from the disk. they must be bluc-shiftecl peaks of a 6.4 keV. line. rather than being emitted by ionized iron. | Thus, if the observed $6.5$ keV and $6.9$ keV lines are emitted from the disk, they must be blue-shifted peaks of a $6.4$ keV line, rather than being emitted by ionized iron. |
This supports the interpretation of "Turneretal. (2002).. | This supports the interpretation of \cite{Turner2002}. . |
we infer that the observed. 6.4. keV. line is emitted from a region e50r, from the central Schwarzschild BL (or closer. fora Werr DII).This corresponds to a time Lag of 20 ks for a BLL mass of 1077" (Zhou&Wang2005).. in good agreement with the variability timescale <36 ks [found in two observations 2002:Longinottietal. 2004).. | we infer that the observed $6.4$ keV line is emitted from a region $\approx 50 r_{\rm g}$ from the central Schwarzschild BH (or closer, for a Kerr BH).This corresponds to a time lag of 20 ks for a BH mass of $10^{7.90}$ \citep{Zhou2005}, in good agreement with the variability timescale $<36$ ks found in two observations \citep{Petrucci2002,Longinotti2004}. |
Iron at the surface of an accretion disk is significantly ionized when the Ecelington ratio is larger than a critical value. | Iron at the surface of an accretion disk is significantly ionized when the Eddington ratio is larger than a critical value. |
Assuming a standard. viscosity parameter a0.1. he critical value above which iron in the innermost part of he disk becomes ionized is Aga0.1 for a Schwarzschild DII. and. Agua~0.3 for à maximally-rotating astrophysical DII. | Assuming a standard viscosity parameter $\alpha \sim0.1$, the critical value above which iron in the innermost part of the disk becomes ionized is $\lambda_{\rm Edd} \sim 0.1$ for a Schwarzschild BH, and $\lambda_{\rm Edd} \sim 0.3$ for a maximally-rotating astrophysical BH. |
We studied the radial ionization structure of an X-rav illuminated: accretion disk. and calculated. the energy (increasing with the ionization parameter) of the iron Whe ines emitted. from the disk. | We studied the radial ionization structure of an X-ray illuminated accretion disk, and calculated the energy (increasing with the ionization parameter) of the iron $\alpha$ lines emitted from the disk. |
We plotted those energies as zumilv of curves in the (I.Abaca) plane. parameterized in erms of radial distance of the emitters ancl height of the illuminating X-ray source above the disk. plane Camppost model). for a non-rotating and a maximallv-rotating DLL. | We plotted those energies as family of curves in the $(E_{\rm \alpha},\lambda_{\rm Edd})$ plane, parameterized in terms of radial distance of the emitters and height of the illuminating X-ray source above the disk plane (lamppost model), for a non-rotating and a maximally-rotating BH. |
We compared our model with the observed Ke line energies [rom a sample of AGNs. | We compared our model with the observed $\alpha$ line energies from a sample of AGNs. |
A substantial fraction of ACUNs show highlv-ionized iron emission. | A substantial fraction of AGNs show highly-ionized iron emission. |
The origin of the ionized emission is still debated. | The origin of the ionized emission is still debated. |
Our results suggest that it may come from. two dillerent. sources: theaccretion disk (for Aga=0.1) or the photoionized material in the outflow (for AgiZ0.1). | Our results suggest that it may come from two different sources: theaccretion disk (for $\lambda_{\rm Edd} \ga 0.1$ ) or the photoionized material in the outflow (for $\lambda_{\rm Edd} \la 0.1$ ). |
Our model presented here is based on simple assumptions. such as constant density without vertical stratification (Matt 1993).. but our main goal is to illustrate an important physical elect. which is unlikely to depend substantially on the details of the disk structure. | Our model presented here is based on simple assumptions, such as constant density without vertical stratification \citep{Matt1993}, but our main goal is to illustrate an important physical effect, which is unlikely to depend substantially on the details of the disk structure. |
The critical depends on a. which parameterizes our ignorance of detailed aceretion physies (Jietal.2006:Milleret.al. 2006). | The critical depends on $\alpha$, which parameterizes our ignorance of detailed accretion physics \citep{Ji2006,Miller2006}. |
.. Despite [ον vears of observational. experimental and theoretical studies since Shakura&Sun-vaev (1973)... we are still. unable to determine the. disk Viscosity accurately. | Despite forty years of observational, experimental and theoretical studies since \citet{Shakura1973}, we are still unable to determine the disk viscosity accurately. |
The theoretical dependence. of the observed. iron Ixo. line energy on a suggests that we can reverse the argument: if we have independent measurements ol a DIL mass. spin and luminosity. we can estimate à using the ionization curves in the (IZ,Agi) plane. by combining the information on centroid energy ancl rapid. variability timescale. | The theoretical dependence of the observed iron $\alpha$ line energy on $\alpha$ suggests that we can reverse the argument: if we have independent measurements of a BH mass, spin and luminosity, we can estimate $\alpha$ using the ionization curves in the $(E_{\rm \alpha},\lambda_{\rm Edd})$ plane, by combining the information on centroid energy and rapid variability timescale. |
Lt is plausible that à~0.1 is in agreement of iron line observations of a low AGNs. | It is plausible that $\alpha\sim0.1$ is in agreement of iron line observations of a few AGNs. |
tron near the disk surface cannot be ionized at low accretion rates and low Ecedineton ratios. | Iron near the disk surface cannot be ionized at low accretion rates and low Eddington ratios. |
There is a forbicden region in the (I.Aga) plane. below which ionized. Wa line emission cannot come from an irraciated disk. | There is a forbidden region in the $(E_{\rm \alpha},\lambda_{\rm Edd})$ plane, below which ionized $\alpha$ line emission cannot come from an irradiated disk. |
Observationallv. several low-luminosity ACGNs in that region show Ixo emission features at 6.5 6.9 keV. We argued that such features are either coming from a highlv-ionized outflow. or are bluc-shiftecl components from. fast-moving neutral matter. | Observationally, several low-luminosity AGNs in that region show $\alpha$ emission features at $6.5$ $6.9$ keV. We argued that such features are either coming from a highly-ionized outflow, or are blue-shifted components from fast-moving neutral matter. |
Alternatively. the intermediate energy. line (6.5 6.7 keV) seen in 33516. 77213. ancl Fairall Ü may come from an evaporating/condensating region. as predicted by the disk transition model at Aga~0.01. 0.02 (Rozaiska&Czornv2000:LiuTaam2009:Qiao 2009). | Alternatively, the intermediate energy line $6.5$ $6.7$ keV) seen in 3516, 7213 and Fairall 9 may come from an evaporating/condensating region, as predicted by the disk transition model at $\lambda_{\rm Edd} \sim 0.01$ $0.02$ \citep[]{Czerny2000, Liu2009, Qiao2009}. |
.. Finally. we emphasize that the current observations clo not vet allow us to put robust constraints on the origin of the hiehlv-ionized iron lines. | Finally, we emphasize that the current observations do not yet allow us to put robust constraints on the origin of the highly-ionized iron lines. |
Ehe line parameters derived from X-ray spectral fitting are strongly. mocdel-dependent. andhave large uncertainties. | The line parameters derived from X-ray spectral fitting are strongly model-dependent, andhave large uncertainties. |
Future observations with the next generation of X-ray space telescopes (suchas the proposed GRAVITAS mission) will resolve the profile | Future observations with the next generation of X-ray space telescopes (suchas the proposed mission) will resolve the profile |
The Case of TD 153508 represents an opposite exanrple: high quality spectra revealed. over 60 vears ago. that the star is a binary. while the present speckle observations and the Ilpparcos experimicut did ot succeed in detecting its duplicity. | The case of HD 153808 represents an opposite example: high quality spectra revealed, over 60 years ago, that the star is a binary, while the present speckle observations and the Hipparcos experiment did not succeed in detecting its duplicity. |
The dubious visual duplicity found by previous speckle observations lay Sugeest the presence of a third bods. which. however. cannot be responsible for the SB2 svstem. | The dubious visual duplicity found by previous speckle observations may suggest the presence of a third body, which, however, cannot be responsible for the SB2 system. |
These two objects clearly show that a single best method to detect binaries docs not exist: this is confined by the fact that the positive duplicitv detection has been obtained for two stars which are not the brightest. nor the uearest objects (see V and x values in Table 1) and not even those observed under the best concditious. | These two objects clearly show that a single best method to detect binaries does not exist; this is confirmed by the fact that the positive duplicity detection has been obtained for two stars which are not the brightest, nor the nearest objects (see V and $\pi$ values in Table 4) and not even those observed under the best conditions. |
We cannot euess which observing :o»proach. direct miaeius or spectroscopy. is iore suitable for duplicity detection: oulv coordinated efforts usine different observational techniques will be efficieut i revealing new binaries which produce a composite spectrum. | We cannot guess which observing approach, direct imaging or spectroscopy, is more suitable for duplicity detection; only coordinated efforts using different observational techniques will be efficient in revealing new binaries which produce a composite spectrum. |
We performed a search of duplicity among candidates usine thle speckle camera of the Catlileo telescope. | We performed a search of duplicity among candidates using the speckle camera of the Galileo telescope. |
We have been able to confirm the. separation and Ao» for two of the program stars: for the others we were able to place stringent upper limits ou the separation of a possible companion. | We have been able to confirm the separation and $\Delta m$ for two of the program stars; for the others we were able to place stringent upper limits on the separation of a possible companion. |
The use of this imstriuneutation Is pronisiug mainly because it allows the determination of both separation and Aw. which is uot always possible by the speckle approach. | The use of this instrumentation is promising mainly because it allows the determination of both separation and $\Delta m$, which is not always possible by the speckle approach. |
Due to the poor weather couditious we were not able to assess if the theoretical diffraction luüt may be actually achieved nor could we establish the limiting magnitude aud maxima Am for successful binarv detection. | Due to the poor weather conditions we were not able to assess if the theoretical diffraction limit may be actually achieved nor could we establish the limiting magnitude and maximum $\Delta m$ for successful binary detection. |
Although we have shown that the speckle camera can work even uudoer bad weather couditious. the observationρα would ereathy benefit from ai good ποσο, | Although we have shown that the speckle camera can work even under bad weather conditions, the observations would greatly benefit from a good seeing. |
Iu such conditions. the speckle camera should allow to reach an angular resolution which is almost an order of uaeuitude better than that obtained by classical eround ράσο. dustruineuts aud comparable with that of space iustruimentation. | In such conditions, the speckle camera should allow to reach an angular resolution which is almost an order of magnitude better than that obtained by classical ground based instruments and comparable with that of space instrumentation. |
emission which. although obviously not well constrained in either case. is seen in both the 2003 and 2005 observations. | emission which, although obviously not well constrained in either case, is seen in both the 2003 and 2005 observations. |
At face value the luminosity of the structured. soft. X-ray emission is higher in the 2005 observation. with 2.7.10 eres + in the 2 gaussian components. a factor ~4 greater than he similarly defined ‘soft excess’ in the 2003 observation. | At face value the luminosity of the structured soft X-ray emission is higher in the 2005 observation, with $2.7\times 10^{42}$ ergs $^{-1}$ in the 2 gaussian components, a factor $\sim$ 4 greater than the similarly defined `soft excess' in the 2003 observation. |
While the soft excess! is not determined. independently of either the absorbing column or the strength and slope of the »ower [aw continuum. light curves for )3-1.0 keV and. 1-10 keV data (figure 7) indicate that the soft [ux is less variable within the 2005 observation. suggesting a significant soft component is separate from. (and more extended than) the »ower Law source. | While the `soft excess' is not determined independently of either the absorbing column or the strength and slope of the power law continuum, light curves for 0.3-1.0 keV and 1-10 keV data (figure 7) indicate that the soft flux is less variable within the 2005 observation, suggesting a significant soft component is separate from (and more extended than) the power law source. |
To obtain a further. measure of the longer-term variability of the soft X-ray component we have tried fitting he 2003 data to the 2005 spectral model (absorbed power aw plus soft. excess) with the power law slope ancl col oorber fixed. | To obtain a further measure of the longer-term variability of the soft X-ray component we have tried fitting the 2003 data to the 2005 spectral model (absorbed power law plus soft excess) with the power law slope and cold absorber fixed. |
The major difference was found to be in he normalisation of the power law. which fell by a factor ]4. | The major difference was found to be in the normalisation of the power law, which fell by a factor of $\sim$ 14. |
Half the remaining excess in chi was remove: v allowing the power law indexto change. à reduction rom ~2.1 to ~1.9 perhaps corresponding to the relatively stronger reflection in the low Ilux spectrum. | Half the remaining excess in $^{2}$ was removed by allowing the power law indexto change, a reduction from $\sim$ 2.1 to $\sim$ 1.9 perhaps corresponding to the relatively stronger reflection in the low flux spectrum. |
Finally. the soft X-ray emission was allowed to vary. an acceptable fit being obtained for a fall in gaussian line lux of a factor ~ 1.6. | Finally, the soft X-ray emission was allowed to vary, an acceptable fit being obtained for a fall in gaussian line flux of a factor $\sim$ 1.6. |
While the above estimate is model dependent. anc a constant soft [Lux is not ruled out. it is clear that the soft. emission component. significant in both oobservations. is much less variable than the power law continuum. | While the above estimate is model dependent, and a constant soft flux is not ruled out, it is clear that the soft X-ray emission component, significant in both observations, is much less variable than the power law continuum. |
Phe relative lack of variability supports an origin of the soft. N-ray emission in an extended outllow. as is actually resolved in nearby tvpe 2 AGN. | The relative lack of variability supports an origin of the soft X-ray emission in an extended outflow, as is actually resolved in nearby type 2 AGN. |
That. physical link has been proposed in the analysis of the N-ray. spectra of other tvpe 1 AGN and a quantitative comparison made in Pounds al.(2005). | That physical link has been proposed in the analysis of the X-ray spectra of other type 1 AGN and a quantitative comparison made in Pounds (2005). |
We revise this comparison here and add our new analysis for M. ‘Table 2 stummarises the results. where the 2-10. keV luminosities. corrected for absorption in our line of sight. are used as a proxy for the ionising Dux irradiating the soft X-ray emission region. | We revise this comparison here and add our new analysis for M. Table 2 summarises the results, where the 2-10 keV luminosities, corrected for absorption in our line of sight, are used as a proxy for the ionising flux irradiating the soft X-ray emission region. |
The data indicate a trend where the relative streneth of the soft X-ray emission in type 1XGN is typically an order of magnitude greater than for type 2 ACN. | The data indicate a trend where the relative strength of the soft X-ray emission in type 1 AGN is typically an order of magnitude greater than for type 2 AGN. |
In that context the intermediate value for iis consistent with its intermediate optical type. supporting the view that the soft X-ray emission typically arises from an ionisecl outllow originating at a smaller radius the DLIt. possibly driven off the same cold matter seen in absorption. | In that context the intermediate value for is consistent with its intermediate optical type, supporting the view that the soft X-ray emission typically arises from an ionised outflow originating at a smaller radius the BLR, possibly driven off the same cold matter seen in absorption. |
In that context we note that energeticallv the soft. X-ray emission in the 2005 observation of ccorresponds to only 75 r. of the power law continuum Lux removed by the cold absorber. | In that context we note that energetically the soft X-ray emission in the 2005 observation of corresponds to only $\sim$ 5 of the power law continuum flux removed by the cold absorber. |
Analvsing the high energy spectrum of iis unusually challenging cue to the presence of apparently quite strong emission. and absorption features which. however. are not consistent between the pn and. MOS data. | Analysing the high energy spectrum of is unusually challenging due to the presence of apparently quite strong emission and absorption features which, however, are not consistent between the pn and MOS data. |
These cillerences remain. although at a reduced level. when the background subtraction is removed. | These differences remain, although at a reduced level, when the background subtraction is removed. |
Finding no other explanation than limited statistics we therefore analysed the source-only spectra for the pn ancl MOS data combined. | Finding no other explanation than limited statistics we therefore analysed the source-only spectra for the pn and MOS data combined. |
WeὉ lindfind a marginallyeinall significanteni1 emission |line at[ an energy consistent with Fe-Ix lluorescence from low ionisation matter. | We find a marginally significant emission line at an energy consistent with Fe-K fluorescence from low ionisation matter. |
The equivalent width is consistent with continuum rellection being much less significant. (relative to the direc power law) aan in the 2003 observation. | The equivalent width is consistent with continuum reflection being much less significant (relative to the direct power law) than in the 2003 observation. |
At the low leve detected. scattering. from the cold. absorber might be a candidate source. | At the low level detected, scattering from the cold absorber might be a candidate source. |
A stronger fall in sensitivity in the Fe Ix. band. woul explain why the MOS camera only detects the absorption feature observed at 6.9 keV. (7.9 keV in the AGN res frame). | A stronger fall in sensitivity in the Fe K band would explain why the MOS camera only detects the absorption feature observed at $\sim$ 6.9 keV $\sim$ 7.9 keV in the AGN rest frame). |
Figure 5 suggests an absorption line. rather than an absorption edge. and indeed that choice is statistically preferred. | Figure 5 suggests an absorption line, rather than an absorption edge, and indeed that choice is statistically preferred. |
1£ real. the most. likely identification is with resonance line absorption in highly. ionised. Fe. | If real, the most likely identification is with resonance line absorption in highly ionised Fe. |
For He-like FeXNXV the measured. line energy. would imply an outflow velocity of v—0.15c. | For He-like FeXXV the measured line energy would imply an outflow velocity of $\sim$ 0.15c. |
The broader absorption feature near ~7.6 keV. (~ 8.7 keV in the AGN rest frame). only detected in the pn camera. is better modelled with an absorption edge. | The broader absorption feature near $\sim$ 7.6 keV $\sim$ 8.7 keV in the AGN rest frame), only detected in the pn camera, is better modelled with an absorption edge. |
Intriguinglv. the Ix-edge of Le-like FONAY (threshold energy 8.83 keV: Verner 11996) lies close to the derived. edge energy. | Intriguingly, the K-edge of He-like FeXXV (threshold energy 8.83 keV; Verner 1996) lies close to the derived edge energy. |
With that identification and a threshold cross section of 10.7" eni? (Verner 11996) the measured edge optical depth of ~0.3 implies an absorbing column density of Nevxvo1.5- 107 | With that identification and a threshold cross section of $\times 10^{-20}$ $^{2}$ (Verner 1996) the measured edge optical depth of $\sim$ 0.3 implies an absorbing column density of $_{FeXXV}$$\sim$ $\times 10^{19}$ $^{-2}$. |
Assuming Fe XXV to be the dominant ion (likely over a rather wide range of ionisation parameter in a highlv ionised eas. and noting no evidence for an FeXNVI edge). this corresponds. for a solar abundance of Fe. to a column density of Ng 5.1077 em2 | Assuming Fe XXV to be the dominant ion (likely over a rather wide range of ionisation parameter in a highly ionised gas, and noting no evidence for an FeXXVI edge), this corresponds, for a solar abundance of Fe, to a column density of $_{H}$$\sim$ $\times 10^{23}$ $^{-2}$ . |
There have been an increasing number of reports of highly ionised gas imprinting Fe Ix. features on AGN X-ray | There have been an increasing number of reports of highly ionised gas imprinting Fe K features on AGN X-ray |
in (he intervening cluster evolution make this difficult. | in the intervening cluster evolution make this difficult. |
For example. binaries can be formed and destroved in a variety of interactions between cluster members (IIurlev Shara 2002). | For example, binaries can be formed and destroyed in a variety of interactions between cluster members (Hurley Shara 2002). |
Binaries will on average be more massive than single stars and thus are affected differently bv mass segregation. | Binaries will on average be more massive than single stars and thus are affected differently by mass segregation. |
Also. the escape rates of single stars and binaries will differ. | Also, the escape rates of single stars and binaries will differ. |
Finally. the internal evolution of (he components of binaries can also lead to binaries’ destruction. | Finally, the internal evolution of the components of binaries can also lead to binaries' destruction. |
Current simulation techniques have been designed to model (hese (aud other) processes (Aarseth 2003) and have reached the level of sophistication required to produce realistic Cluster models. | Current simulation techniques have been designed to model these (and other) processes (Aarseth 2003) and have reached the level of sophistication required to produce realistic cluster models. |
In (his wav the link between primordial aud current cluster binary populations can be investigated cdirectlv (e.g. IIulev οἱ al. | In this way the link between primordial and current cluster binary populations can be investigated directly (e.g. Hurley et al. |
2005: Ivanova et al. | 2005; Ivanova et al. |
2005). | 2005). |
Aarseth (1996) conducted an N-body simulation starting with 10000 stars and a binary [reeueney. where notably the stars were drawn from a realistic initial mass function (IME). the cluster was subject to the tidal field of the Galaxy. and both stellar and binary evolution were modelled. | Aarseth (1996) conducted an $N$ -body simulation starting with $10\,000$ stars and a binary frequency where notably the stars were drawn from a realistic initial mass function (IMF), the cluster was subject to the tidal field of the Galaxy, and both stellar and binary evolution were modelled. |
This model cluster had a halflife of about 2 Gyr al which point the core binary. lrequency had risen to primarily owing to mass-segregation. | This model cluster had a half-life of about $2\,$ Gyr at which point the core binary frequency had risen to primarily owing to mass-segregation. |
Thus binaries were not preferentially depleted. | Thus binaries were not preferentially depleted. |
In this case it was not necessary to include a laree initial binary. fraction in order to halt core-collapse ancl vield a significant observed. abundance in the central regions. | In this case it was not necessary to include a large initial binary fraction in order to halt core-collapse and yield a significant observed abundance in the central regions. |
The earlier work of MeMillan Hut (1994) reported N-body simulations of 2000 stars or less and binary [requencies in the range of5-20%. | The earlier work of McMillan Hut (1994) reported $N$ -body simulations of $2\,000$ stars or less and binary frequencies in the range of. |
. Thev included the Galactic tidal field. but only considered point-mass dynamics. | They included the Galactic tidal field but only considered point-mass dynamics. |
McMillan Hut (1994) showed Chat Chere is a critical primordial binary frequency of below which the binaries are destvoved before the cluster dissolves owing to the tidal field. | McMillan Hut (1994) showed that there is a critical primordial binary frequency of below which the binaries are destroyed before the cluster dissolves owing to the tidal field. |
Furthermore. they found that above this critical value (here exists a muninnun possible binary mass traction lor the cluster this result could be used wilh observations of present-day binary frequency (o place limits on the primordial frequency. | Furthermore, they found that above this critical value there exists a minimum possible binary mass fraction for the cluster – this result could be used with observations of present-day binary frequency to place limits on the primordial frequency. |
We note that the AleMillan Int (1994) simulations were restricted to stars. and the binaries were a [actor of two heavier then single stars this could give misleading results when applied to realclusters?. | We note that the McMillan Hut (1994) simulations were restricted to equal-mass stars, and the binaries were a factor of two heavier then single stars – this could give misleading results when applied to real. |
. These .N-bocdy simulations were definitely in (he open cluster regime. | These $N$ -body simulations were definitely in the open cluster regime. |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.