The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Juan Antonio Belmonte - One of the best experts on this subject based on the ideXlab platform.
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
EPJ Web of Conferences, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We identify and characterize secondary Eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b Eclipses.
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secondary Eclipses in the corot light curves
EPJ Web of Conferences, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We identify and characterize secondary Eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b Eclipses. Secondary eclipse observations of transiting extrasolar planets allow us to study the planetary and orbital properties not attainable by the transit and radial velocity (RV) observations alone. The two main measurables, planet's albedo and brightness temperature, are strongly coupled with the structure and dynamics of the atmosphere, and can be used to educe information about the physical processes governing the atmosphere. Due to the complexity of the physics involved, this additional empirical knowledge is highly valuable when aiming to understand the planetary atmospheres via theoretical modeling. Eclipses also yield information about the planet's orbit. The eclipse center times and durations allow us to constrain the orbit's eccentricity and argument of periastron to a higher precision than with RV observations alone. This is especially true for the planets orbiting faint or rapidly rotating stars, for which precise RV observations are difficult to obtain. The CoRoT planets are based on one of the highest-precision data sets available, and all of them have been thoroughly characterized in their respective discovery papers. Here we abridge the results of our homogeneous search for secondary Eclipses in the light curves of all CoRoT planets published until June 2012, namely CoRoT 1b to 23b, including the brown dwarf 15b, but excluding the yet unpublished planet 22b. A more in-depth view to the work is given in (1).
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
Astronomy and Astrophysics, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:ABSTRACT Aims. We aim to identify and characterize secondary planet Eclipses in the original light curves of all published CoRoT planets usinguniform detection and evaluation critetia.Methods. Our analysis is based on a Bayesian model selection between two competing models: one with and one without an Eclipsesignal. The search is carried out by mapping the Bayes factor in favor of the eclipse model as a function of the eclipse center time,after which the characterization of plausible eclipse candidates is done by estimating the posterior distributions of the eclipse modelparameters using Markov Chain Monte Carlo.Results. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf,CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b. Thepreviously published CoRoT-1b and CoRoT-2b Eclipses are also confirmed. Key words. Planetary systems – Methods: statistical – Eclipses
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
arXiv: Earth and Planetary Astrophysics, 2012Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We aim to identify and characterize secondary Eclipses in the original light curves of all published CoRoT planets using uniform detection and evaluation critetia. Our analysis is based on a Bayesian model selection between two competing models: one with and one without an eclipse signal. The search is carried out by mapping the Bayes factor in favor of the eclipse model as a function of the eclipse center time, after which the characterization of plausible eclipse candidates is done by estimating the posterior distributions of the eclipse model parameters using Markov Chain Monte Carlo. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b. The previously published CoRoT-1b and CoRoT-2b Eclipses are also confirmed.
H Parviainen - One of the best experts on this subject based on the ideXlab platform.
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
EPJ Web of Conferences, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We identify and characterize secondary Eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b Eclipses.
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secondary Eclipses in the corot light curves
EPJ Web of Conferences, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We identify and characterize secondary Eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b Eclipses. Secondary eclipse observations of transiting extrasolar planets allow us to study the planetary and orbital properties not attainable by the transit and radial velocity (RV) observations alone. The two main measurables, planet's albedo and brightness temperature, are strongly coupled with the structure and dynamics of the atmosphere, and can be used to educe information about the physical processes governing the atmosphere. Due to the complexity of the physics involved, this additional empirical knowledge is highly valuable when aiming to understand the planetary atmospheres via theoretical modeling. Eclipses also yield information about the planet's orbit. The eclipse center times and durations allow us to constrain the orbit's eccentricity and argument of periastron to a higher precision than with RV observations alone. This is especially true for the planets orbiting faint or rapidly rotating stars, for which precise RV observations are difficult to obtain. The CoRoT planets are based on one of the highest-precision data sets available, and all of them have been thoroughly characterized in their respective discovery papers. Here we abridge the results of our homogeneous search for secondary Eclipses in the light curves of all CoRoT planets published until June 2012, namely CoRoT 1b to 23b, including the brown dwarf 15b, but excluding the yet unpublished planet 22b. A more in-depth view to the work is given in (1).
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
Astronomy and Astrophysics, 2013Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:ABSTRACT Aims. We aim to identify and characterize secondary planet Eclipses in the original light curves of all published CoRoT planets usinguniform detection and evaluation critetia.Methods. Our analysis is based on a Bayesian model selection between two competing models: one with and one without an Eclipsesignal. The search is carried out by mapping the Bayes factor in favor of the eclipse model as a function of the eclipse center time,after which the characterization of plausible eclipse candidates is done by estimating the posterior distributions of the eclipse modelparameters using Markov Chain Monte Carlo.Results. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf,CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b. Thepreviously published CoRoT-1b and CoRoT-2b Eclipses are also confirmed. Key words. Planetary systems – Methods: statistical – Eclipses
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secondary Eclipses in the corot light curves a homogeneous search based on bayesian model selection
arXiv: Earth and Planetary Astrophysics, 2012Co-Authors: H Parviainen, H J Deeg, Juan Antonio BelmonteAbstract:We aim to identify and characterize secondary Eclipses in the original light curves of all published CoRoT planets using uniform detection and evaluation critetia. Our analysis is based on a Bayesian model selection between two competing models: one with and one without an eclipse signal. The search is carried out by mapping the Bayes factor in favor of the eclipse model as a function of the eclipse center time, after which the characterization of plausible eclipse candidates is done by estimating the posterior distributions of the eclipse model parameters using Markov Chain Monte Carlo. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b. The previously published CoRoT-1b and CoRoT-2b Eclipses are also confirmed.
C B Markwardt - One of the best experts on this subject based on the ideXlab platform.
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discovery of Eclipses from the accreting millisecond x ray pulsar swift j1749 4 2807
The Astrophysical Journal, 2010Co-Authors: C B Markwardt, Tod E StrohmayerAbstract:We report the discovery of X-ray Eclipses in the recently discovered accreting millisecond X-ray pulsar SWIFT J1749.4-2807. This is the first detection of X-ray Eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 M{sub sun} for a likely range of neutron star masses, and that it is larger than a main-sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90{sup 0} longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172 {+-} 13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of 'Shapiro' delay due to general relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 M{sub sun}.
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discovery of Eclipses from the accreting millisecond x ray pulsar swift j1749 4 2807
arXiv: High Energy Astrophysical Phenomena, 2010Co-Authors: C B Markwardt, Tod E StrohmayerAbstract:We report the discovery of X-ray Eclipses in the recently discovered accreting millisecond X-ray pulsar Swift J1749.4-2807. This is the first detection of X-ray Eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 M_sun for a likely range of neutron star masses, and that it is larger than a main sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90 deg longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172 +/- 13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of "Shapiro" delay due to General Relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 M_sun.
J W Broderick - One of the best experts on this subject based on the ideXlab platform.
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the low frequency radio Eclipses of the black widow pulsar j1810 1744
Monthly Notices of the Royal Astronomical Society, 2018Co-Authors: E. J. Polzin, R P Breton, J W T Hessels, B W Stappers, A.o. Clarke, V.i. Kondratiev, C.g. Bassa, J W BroderickAbstract:We have observed and analysed the Eclipses of the black widow pulsar J1810+1744 at low radio frequencies. Using LOw-Frequency ARray (LOFAR) and Westerbork Synthesis Radio Telescope observations between 2011 and 2015, we have measured variations in flux density, dispersion measure, and scattering around Eclipses. High-time resolution, simultaneous beamformed, and interferometric imaging LOFAR observations show concurrent disappearance of pulsations and total flux from the source during the Eclipses, with a 3σ upper limit of 36 mJy ( < 10 per cent of the pulsar's averaged out-of-eclipse flux density). The dispersion measure variations are highly asymmetric, suggesting a tail of material swept back due to orbital motion. The egress deviations are variable on time-scales shorter than the 3.6 h orbital period and are indicative of a clumpy medium. Additional pulse broadening detected during egress is typically < 20 per cent of the pulsar's spin period, showing no evidence of scattering the pulses beyond detectability in the beamformed data. The Eclipses, lasting ∼ 13 per cent of the orbit at 149 MHz, are shown to be frequency-dependent with total duration scaling as ∝ ν^−0.41 ± 0.03. The results are discussed in the context of the physical parameters of the system, and an examination of eclipse mechanisms reveals cyclotron–synchrotron absorption as the most likely primary cause, although non-linear scattering mechanisms cannot be quantitatively ruled out. The inferred mass-loss rate is a similar order of magnitude to the mean rate required to fully evaporate the companion in a Hubble time.
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The Low-Frequency Radio Eclipses of the Black Widow Pulsar J1810+1744
Monthly Notices of the Royal Astronomical Society, 2018Co-Authors: E. J. Polzin, J W Broderick, R P Breton, J W T Hessels, B W Stappers, A.o. Clarke, V.i. Kondratiev, C.g. Bassa, J.m. Grießmeier, C. SobeyAbstract:We have observed and analysed the Eclipses of the black widow pulsar J1810+1744 at low radio frequencies. Using LOw-Frequency ARray (LOFAR) and Westerbork Synthesis Radio Telescope observations between 2011 and 2015, we have measured variations in flux density, dispersion measure, and scattering around Eclipses. High-time resolution, simultaneous beamformed, and interferometric imaging LOFAR observations show concurrent disappearance of pulsations and total flux from the source during the Eclipses, with a 3σ upper limit of 36 mJy ( < 10 per cent of the pulsar's averaged out-of-eclipse flux density). The dispersion measure variations are highly asymmetric, suggesting a tail of material swept back due to orbital motion. The egress deviations are variable on time-scales shorter than the 3.6 h orbital period and are indicative of a clumpy medium. Additional pulse broadening detected during egress is typically < 20 per cent of the pulsar's spin period, showing no evidence of scattering the pulses beyond detectability in the beamformed data. The Eclipses, lasting ∼ 13 per cent of the orbit at 149 MHz, are shown to be frequency-dependent with total duration scaling as ∝ ν^−0.41 ± 0.03. The results are discussed in the context of the physical parameters of the system, and an examination of eclipse mechanisms reveals cyclotron–synchrotron absorption as the most likely primary cause, although non-linear scattering mechanisms cannot be quantitatively ruled out. The inferred mass-loss rate is a similar order of magnitude to the mean rate required to fully evaporate the companion in a Hubble time.
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low radio frequency Eclipses of the redback pulsar j2215 5135 observed in the image plane with lofar
Monthly Notices of the Royal Astronomical Society, 2016Co-Authors: J W Broderick, R P Fender, R P Breton, A Stewart, A Rowlinson, J Swinbank, J W T Hessels, T D Staley, A J Van Der Horst, M E BellAbstract:The Eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks – six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν −0.4), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the Eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.
Drake Deming - One of the best experts on this subject based on the ideXlab platform.
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spitzer secondary Eclipses of qatar 1b
Astronomy and Astrophysics, 2018Co-Authors: Emily Garhart, Drake Deming, Heather A Knutson, Avi Mandell, Jonathan J FortneyAbstract:Aims. Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods. We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 μm wavelengths. We used pixel-level decorrelation to correct for Spitzer’s intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases. Results. Our 3.6 μm eclipse depth is 0.149 ± 0.051% and the 4.5 μm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71 K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885 K) as indicated by the ground-based Eclipses in the Ks band, unless the planet’s emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer Eclipses is 0.4984 ± 0.0017, yielding e cos ω = −0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations.
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spitzer secondary Eclipses of the dense modestly irradiated giant exoplanet hat p 20b using pixel level decorrelation
The Astrophysical Journal, 2015Co-Authors: Drake Deming, Heather A Knutson, Joshua A Kammer, Benjamin J Fulton, James G Ingalls, Sean Carey, Adam Burrows, Jonathan J Fortney, Kamen O TodorovAbstract:HAT-P-20b is a giant metal-rich exoplanet orbiting a metal-rich star. We analyze two secondary Eclipses of the planet in each of the 3.6 and 4.5 μm bands of Warm Spitzer. We have developed a simple, powerful, and radically different method to correct the intra-pixel effect for Warm Spitzer data, which we call pixel-level decorrelation (PLD). PLD corrects the intra-pixel effect very effectively, but without explicitly using—or even measuring—the fluctuations in the apparent position of the stellar image. We illustrate and validate PLD using synthetic and real data and comparing the results to previous analyses. PLD can significantly reduce or eliminate red noise in Spitzer secondary eclipse photometry, even for Eclipses that have proven to be intractable using other methods. Our successful PLD analysis of four HAT-P-20b Eclipses shows a best-fit blackbody temperature of 1134 ± 29 K, indicating inefficient longitudinal transfer of heat, but lacking evidence for strong molecular absorption. We find sufficient evidence for variability in the 4.5 μm band that the Eclipses should be monitored at that wavelength by Spitzer, and this planet should be a high priority for James Webb Space Telescope spectroscopy. All four Eclipses occur about 35 minutes after orbital phase 0.5, indicating a slightly eccentric orbit. A joint fit of the eclipse and transit times with extant RV data yields e cos ω = 0.01352^(+0.00054)_(-0.00057) and establishes the small eccentricity of the orbit to high statistical confidence. HAT-P-20b is another excellent candidate for orbital evolution via Kozai migration or other three-body mechanisms.
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spitzer secondary Eclipses of the dense modestly irradiated giant exoplanet hat p 20b using pixel level decorrelation
arXiv: Earth and Planetary Astrophysics, 2014Co-Authors: Drake Deming, Heather A Knutson, Joshua A Kammer, Benjamin J Fulton, James G Ingalls, Sean Carey, Adam Burrows, Jonathan J Fortney, Kamen O TodorovAbstract:HAT-P-20b is a giant exoplanet that orbits a metal-rich star. The planet itself has a high total density, suggesting that it may also have a high metallicity in its atmosphere. We analyze two Eclipses of the planet in each of the 3.6- and 4.5 micron bands of Warm Spitzer. These data exhibit intra-pixel detector sensitivity fluctuations that were resistant to traditional decorrelation methods. We have developed a simple, powerful, and radically different method to correct the intra-pixel effect for Warm Spitzer data, which we call pixel-level decorrelation (PLD). PLD corrects the intra-pixel effect very effectively, but without explicitly using - or even measuring - the fluctuations in the apparent position of the stellar image. We illustrate and validate PLD using synthetic and real data, and comparing the results to previous analyses. PLD can significantly reduce or eliminate red noise in Spitzer secondary eclipse photometry, even for Eclipses that have proven to be intractable using other methods. Our successful PLD analysis of four HAT-P-20b Eclipses shows a best-fit blackbody temperature of 1134 +/-29K, indicating inefficient longitudinal transfer of heat, but lacking evidence for strong molecular absorption. We find sufficient evidence for variability in the 4.5 micron band that the Eclipses should be monitored at that wavelength by Spitzer, and this planet should be a high priority for JWST spectroscopy. All four Eclipses occur about 35 minutes after orbital phase 0.5, indicating a slightly eccentric orbit. A joint fit of the eclipse and transit times with extant RV data yields e(cos{omega}) = 0.01352 (+0.00054, -0.00057), and establishes the small eccentricity of the orbit to high statistical confidence. Given the existence of a bound stellar companion, HAT-P-20b is another excellent candidate for orbital evolution via Kozai migration or other three-body mechanism.
