D. Ricci

Publications (87)100.2 Total impact

• Article: A detailed census of variable stars in the globular cluster NGC 6333 (M9) from CCD differential photometry

  A. Arellano Ferro, D. M. Bramich, R. Figuera Jaimes, Sunetra Giridhar, N. Kains, K. Kuppuswamy, U. G. Jørgensen, K. A. Alsubai, J. M. Andersen, V. Bozza, [......], S. Rahvar, D. Ricci, G. Scarpetta, J. Skottfelt, C. Snodgrass, J. Southworth, J. Surdej, J. Tregloan-Reed, C. Vilela, O. Wertz
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  ABSTRACT: We report CCD $V$ and $I$ time-series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05 mag for stars brighter than $V \sim 19.0$ mag, even in the crowded central regions of the cluster. The high photometric precision has resulted in the discovery of two new RRc stars, three eclipsing binaries, seven long-term variables and one field RRab star behind the cluster. A detailed identification chart and equatorial coordinates are given for all the variable stars in the field of our images of the cluster. Our data together with literature $V$-data obtained in 1994 and 1995 allowed us to refine considerably the periods for all RR Lyrae stars. The nature of the new variables is discussed. We argue that variable V12 is a cluster member and an Anomalous Cepheid. Secular period variations, double mode pulsations and/or the Blazhko-like modulations in some RRc variables are addressed. Through the light curve Fourier decomposition of 12 RR Lyrae stars we have calculated a mean metallicity of [Fe/H]$_{\rm ZW}$=$-1.70 \pm 0.01{\rm(statistical)} \pm 0.14{\rm(systematic)}$ or [Fe/H]$_{UVES}=-1.67 \pm 0.01{\rm(statistical)} \pm 0.19{\rm(systematic)}$.Absolute magnitudes, radii and masses are also estimated for the RR Lyrae stars. A detailed search for SX Phe stars in the Blue Straggler region was conducted but none were discovered. If SX Phe exist in the cluster then their amplitudes must be smaller than the detection limit of our photometry. The CMD has been corrected for heavy differential reddening using the detailed extinction map of the cluster of Alonso-Garc\'ia et al. (2012). This has allowed us to set the mean cluster distance from two independent estimates; from the RRab and RRc absolute magnitudes, we find $8.04\pm 0.19$ kpc and $7.88\pm0.30$ kpc respectively.
  06/2013;
• Article: Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry

  N. Kains, D. M. Bramich, A. Arellano Ferro, R. Figuera Jaimes, U. G. Jørgensen, S. Giridhar, K. A. Alsubai, J. M. Andersen, V. Bozza, P. Browne, [......], K. Sahu, G. Scarpetta, J. Skottfelt, C. Snodgrass, J. Southworth, J. Surdej, J. Tregloan-Reed, C. Vilela, O. Wertz, A. Williams
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  ABSTRACT: We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derive an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]_ZW=-2.01 +- 0.04, or [Fe/H]_UVES=-2.11 +- 0.06, and a distance of 8.32 +- 0.20 kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35 +- 0.42 kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0 +- 1.0 Gyr for M 30.
  05/2013;
• Source

  Available from: Jeremy Tregloan-Reed

  Article: A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251

  N. Kains, R. Street, J. -Y. Choi, C. Han, A. Udalski, L. A. Almeida, F. Jablonski, P. Tristram, U. G. Jorgensen, M. K. Szymanski, [......], S. R. Kane, D. Kubas, J. -B. Marquette, R. Martin, P. Meintjes, J. Menzies, K. R. Pollard, A. Williams, D. Wouters, M. Zub
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  ABSTRACT: We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. We find that the lens is made up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a mass of 0.26 +- 0.11 M_Sun. The planetary system is located at a distance of 2.57 +- 0.61 kpc towards the Galactic Centre. The projected separation of the planet from its host star is d=1.408 +- 0.019, in units of the Einstein radius, which corresponds to 2.72 +- 0.75 AU in physical units. We also identified a competitive model with similar planet and host star masses, but with a smaller orbital radius of 1.50 +- 0.50 AU. The planet is therefore located beyond the snow line of its host star, which we estimate to be around 1-1.5 AU.
  03/2013;
• Source

  Available from: Jeremy Tregloan-Reed

  Article: Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs

  J. -Y. Choi, C. Han, A. Udalski, T. Sumi, B. S. Gaudi, A. Gould, D. P. Bennett, M. Dominik, J. -P. Beaulieu, Y. Tsapras, [......], J. Greenhill, D. Kubas, J. -B. Marquette, J. W. Menzies, K. C. Sahu, M. Zub, D. M. Bramich, K. Horne, I. A. Steele, R. A. Street
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  ABSTRACT: Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low-mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 Msun and 0.034 Msun, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field brown-dwarf binaries known. The discovery of a population of such binaries indicates that brown dwarf binaries can robustly form at least down to masses of ~0.02 Msun. Future microlensing surveys will measure a mass-selected sample of brown-dwarf binary systems, which can then be directly compared to similar samples of stellar binaries.
  02/2013;
• Article: Flux and color variations of the doubly imaged quasar UM673

  D. Ricci, A. Elyiv, F. Finet, O. Wertz, K. Alsubai, T. Anguita, V. Bozza, P. Browne, M. Burgdorf, S. Calchi Novati, [......], F. Schönebeck, R. Schmidt, J. Skottfelt, C. Snodgrass, J. Southworth, C. C. Thöne, J. Wambsganss, F. Zimmer, M. Zub, J. Surdej
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  ABSTRACT: With the aim of characterizing the flux and color variations of the multiple components of the gravitationally lensed quasar UM673 as a function of time, we have performed multi-epoch and multi-band photometric observations with the Danish 1.54m telescope at the La Silla Observatory. The observations were carried out in the VRi spectral bands during four seasons (2008--2011). We reduced the data using the PSF (Point Spread Function) photometric technique as well as aperture photometry. Our results show for the brightest lensed component some significant decrease in flux between the first two seasons (+0.09/+0.11/+0.05 mag) and a subsequent increase during the following ones (-0.11/-0.11/-0.10 mag) in the V/R/i spectral bands, respectively. Comparing our results with previous studies, we find smaller color variations between these seasons as compared with previous ones. We also separate the contribution of the lensing galaxy from that of the fainter and close lensed component.
  02/2013;
• Article: MOA-2010-BLG-523: "Failed Planet" = RS CVn Star

  A Gould, J ~C Yee, I ~A Bond, A Udalski, C Han, U ~G Jørgensen, J Greenhill, Y Tsapras, M ~H Pinsonneault, T Bensby, [......], C ~B Henderson, D Kubas, J -B Marquette, R Martin, J ~W Menzies, B Shappee, A Williams, J Saders, M Zub, The PLANET Collaboration
  apj. 02/2013; 763:141.
• Source

  Available from: Christos Leonidopoulos

  Article: A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

  D. Abbaneo, G. Abbiendi, M. Abbrescia, S. Abdullin, A. Abdulsalam, B.S. Acharya, D. Acosta, J.G. Acosta, A. Adair, W. Adam, [......], M.H. Zoeller, O. Zorba, P. Zotto, W. Zou, G. Zumerle, M. Zupan, A. Zuranski, R. Zuyeuski, M. Zvada, P. Zych
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  ABSTRACT: The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force—the W+, W–, and Z0 bosons—as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 × 106. The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga–electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle.
  Science 12/2012; 338(6114):1569-1575. · 31.20 Impact Factor
• Article: Microlensing Binaries with Candidate Brown Dwarf Companions

  I -G Shin, C Han, A Gould, A Udalski, T Sumi, M Dominik, J -P Beaulieu, Y Tsapras, V Bozza, M ~K Szyma'nski, [......], J -B Marquette, R Martin, P Meintjes, J Menzies, K ~R Pollard, K ~C Sahu, J Wambsganss, A Williams, C Vinter, M Zub
  The Astrophysical Journal 12/2012; 760:116. · 6.02 Impact Factor
• Article: MOA-2010-BLG-073L: An M-Dwarf with a Substellar Companion at the Planet/Brown Dwarf Boundary

  R. A. Street, J. -Y. Choi, Y. Tsapras, C. Han, K. Furusawa, M. Hundertmark, A. Gould, T. Sumi, I. A. Bond, D. Wouters, [......], M. Mathiasen, M. T. Penny, S. Proft, S. Rahvar, D. Ricci, G. Scarpetta, S. Schafer, F. Schonebeck, J. Southworth, J. Surdej
  [show abstract] [hide abstract]
  ABSTRACT: We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source lightcurve, we demonstrate that it is an irregular variable over time scales >200d. Its dereddened color, $(V-I)_{S,0}$, is 1.221$\pm$0.051mag and from our lens model we derive a source radius of 14.7$\pm$1.3 $R_{\odot}$, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q=0.0654$\pm$0.0006. The Einstein crossing time of the event, $T_{\rm{E}}=44.3$\pm$0.1d, was sufficiently long that the lightcurve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, $D_L$=2.8$\pm$0.4kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with $M_{L,p}$=0.16$\pm0.03M_{\odot}$ while the companion has $M_{L,s}$=11.0$\pm2.0M_{\rm{J}}$ putting it in the boundary zone between planets and brown dwarfs.
  11/2012;
• Article: A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L

  E Bachelet, P Fouqué, C Han, A Gould, M ~D Albrow, J -P Beaulieu, E Bertin, I ~A Bond, G ~W Christie, D Heyrovský, [......], G Maier, L Mancini, S Rahvar, D Ricci, G Scarpetta, J Skottfelt, J Southworth, J Surdej, F Zimmer, Mindstep Consortium
  Astronomy and Astrophysics 11/2012; 547:A55. · 4.59 Impact Factor
• Article: MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection

  J. C. Yee, L. -W. Hung, I. A. Bond, W. Allen, L. A. G. Monard, M. D. Albrow, P. Fouque, M. Dominik, Y. Tsapras, A. Udalski, [......], S. Rahvar, D. Ricci, K. C. Sahu, G. Scarpetta, S. Schafer, F. Schonebeck, C. Snodgrass, J. Southworth, J. Surdej, J. Wambsgans
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  ABSTRACT: We analyze MOA-2010-BLG-311, a high magnification (A_max>600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit this event with both a point lens and a 2-body lens model and find that the 2-body lens model is a better fit but with only Delta chi^2~140. The preferred mass ratio between the lens star and its companion is $q=10^(-3.7+/-0.1), placing the candidate companion in the planetary regime. Despite the formal significance of the planet, we show that because of systematics in the data the evidence for a planetary companion to the lens is too tenuous to claim a secure detection. When combined with analyses of other high-magnification events, this event helps empirically define the threshold for reliable planet detection in high-magnification events, which remains an open question.
  10/2012;
• Article: MOA-2010-BLG-523: "Failed Planet" = RS CVn Star

  A. Gould, J. C. Yee, I. A. Bond, A. Udalski, C. Han, U. G. Jorgensen, J. Greenhill, Y. Tsapras, M. H. Pinsonneault, T. Bensby, [......], P. Fouque, C. B. Henderson, D. Kubas, J. -B Marquette, R. Martin, J. W. Menzies, B. Shappee, A. Williams, J. van Saders, M. Zub
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  ABSTRACT: The Galactic bulge source MOA-2010-BLG-523S exhibited short-term deviations from a standard microlensing lightcurve near the peak of an Amax ~ 265 high-magnification microlensing event. The deviations originally seemed consistent with expectations for a planetary companion to the principal lens. We combine long-term photometric monitoring with a previously published high-resolution spectrum taken near peak to demonstrate that this is an RS CVn variable, so that planetary microlensing is not required to explain the lightcurve deviations. This is the first spectroscopically confirmed RS CVn star discovered in the Galactic bulge.
  10/2012;
• Article: MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection

  J ~C Yee, L -W Hung, I ~A Bond, W Allen, L ~A ~G Monard, M ~D Albrow, P Fouque, M Dominik, Y Tsapras, A Udalski, [......], S Rahvar, D Ricci, K ~C Sahu, G Scarpetta, S Schafer, F Schonebeck, C Snodgrass, J Southworth, J Surdej, J Wambsgans
  ArXiv e-prints. 10/2012;
• Article: GJ1214 transits observations (Harpsoe+, 2013)

  K ~B ~W Harpsoe, S Hardis, T ~C Hinse, U ~G Jorgensen, L Mancini, J Southworth, K ~A Alsubai, V Bozza, P Browne, M ~J Burgdorf, [......], D Ricci, K ~C Sahu, G Scarpetta, S Schafer, F Schonebeck, C Snodgrass, J Skottfelt, J Surdej, J Tregloan-Reed, O Wertz
  VizieR Online Data Catalog. 10/2012; 354:99010.
• Article: High-precision photometry by telescope defocusing - IV. Confirmation of the huge radius of WASP-17 b

  J Southworth, T ~C Hinse, M Dominik, X -S Fang, K Harpsøe, U ~G Jørgensen, E Kerins, C Liebig, L Mancini, J Skottfelt, [......], H Kjeldsen, M ~N Lund, M Lundkvist, M Mathiasen, M ~T Penny, S Rahvar, D Ricci, G Scarpetta, C Snodgrass, J Surdej
  mnras. 10/2012; 426:1338-1348.
• Article: MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection

  J ~C Yee, L -W Hung, I ~A Bond, W Allen, L ~A ~G Monard, M ~D Albrow, P Fouque, M Dominik, Y Tsapras, A Udalski, [......], S Rahvar, D Ricci, K ~C Sahu, G Scarpetta, S Schafer, F Schonebeck, C Snodgrass, J Southworth, J Surdej, J Wambsgans
  ArXiv e-prints. 10/2012;
• Article: Thyroglobulin autoantibodies of patients with subacute thyroiditis are restricted to a major B cell epitope.

  F Latrofa, D Ricci, L Montanelli, M A Altea, A Pucci, A Pinchera, P Vitti
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  ABSTRACT: Thyroglobulin autoantibodies (TgAb) can develop in patients with subacute thyroiditis (SAT). Comparison of the epitope pattern of TgAb of patients with SAT, Hashimoto's thyroiditis (HT) [autoimmune thyroid disease (AITD)] and non-toxic multinodular goiter (NTMG) (non-AITD). Serum TgAb from 10 patients with SAT, 45 with HT, and 19 with NTMG were evaluated. Serum TgAb binding to Tg was inhibited by 4 recombinant human TgAb-Fab, recognizing Tg epitope regions A, B, C, and D. The ability of single TgAb-Fab to inhibit the binding of serum TgAb to Tg was evaluated in enzymelinked immunosorbent assay. Levels of inhibition were different for all TgAb-Fab in the 3 groups of patients. Inhibition by region A TgAb-Fab in SAT [50.5 (30.3-62.5)%] (median and 25th to 75th percentiles) was similar to HT [49.0 (38.0-69.5)%] and significantly higher than in NTMG [25.0 (14.0-37.0)%]; by region B TgAb-Fab in SAT [0.0 (0.0-12.5)%] was significantly lower than in HT [28.0 (9.5-48.0)%] and similar to NTMG [9.0 (4.8-20.5)%]; by region C TgAb-Fab in SAT [9.5 (0.0-25.8)%] were similar to HT [23.0 (9.5-41)%] and NTMG [6.5 (1.7-21.5)%]; and by region D TgAb-Fab in SAT [0.0 (0.0-8.0)%] were lower than in HT [12.0 (1.0-28.5)%] and similar to NTMG [1.0 (0.0-5.0)%]. The epitope pattern of TgAb of SAT is restricted to the A region that is immunodominant in AITD and non-AITD. In the majority of patients with SAT, the autoimmune phenomena represent a non-specific and transient response to the release of thyroid antigens, rather than the expression of thyroid autoimmunity.
  Journal of endocrinological investigation 09/2012; 35(8):712-4. · 1.57 Impact Factor
• Article: Microlensig Binaries with Candidate Brown Dwarf Companions

  I. -G. Shin, C. Han, A. Gould, A. Udalski, T. Sumi, M. Dominik, J. -P. Beaulieu, Y. Tsapras, V. Bozza, M. K. Szymański, [......], J. -B. Marquette, R. Martin, P. Meintjes, J. Menzies, K. R. Pollard, K. C. Sahu, J. Wambsganss, A. Williams, C. Vinter, M. Zub
  [show abstract] [hide abstract]
  ABSTRACT: Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation history. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during 2004 - 2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found 7 candidate events, including OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured mass of the brown dwarf companions are (0.02 +/- 0.01) M_Sun and (0.019 +/- 0.002) M_Sun for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well covered light curves increases with new generation searches.
  08/2012;
• Article: High-precision photometry by telescope defocussing. IV. Confirmation of the huge radius of WASP-17b

  John Southworth, M Dominik, X-S Fang, K Harpsoe, U G Jorgensen, E Kerins, C Liebig, L Mancini, J Skottfelt, D R Anderson, [......], H Kjeldsen, M N Lund, M Lundkvist, M Mathiasen, M T Penny, S Rahvar, D Ricci, G Scarpetta, C Snodgrass, J Surdej
  [show abstract] [hide abstract]
  ABSTRACT: We present photometric observations of four transits in the WASP-17 planetary system, obtained using telescope defocussing techniques and with scatters reaching 0.5 mmag per point. Our revised orbital period is 4.0 +/- 0.6 s longer than previous measurements, a difference of 6.6 sigma, and does not support the published detections of orbital eccentricity in this system. We model the light curves using the JKTEBOP code and calculate the physical properties of the system by recourse to five sets of theoretical stellar model predictions. The resulting planetary radius, Rb = 1.932 +/- 0.052 +/- 0.010 Rjup (statistical and systematic errors respectively), provides confirmation that WASP-17b is the largest planet currently known. All fourteen planets with radii measured to be greater than 1.6 Rjup are found around comparatively hot (Teff > 5900 K) and massive (MA > 1.15 Msun) stars. Chromospheric activity indicators are available for eight of these stars, and all imply a low activity level. The planets have small or zero orbital eccentricities, so tidal effects struggle to explain their large radii. The observed dearth of large planets around small stars may be natural but could also be due to observational biases against deep transits, if these are mistakenly labelled as false positives and so not followed up.
  07/2012;
• Article: The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

  K. B. W. Harpsøe, S. Hardis, T. C. Hinse, U. G. Jørgensen, L. Mancini, J. Southworth, K. A. Alsubai, V. Bozza, P. Browne, M. J. Burgdorf, [......], D. Ricci, K. C. Sahu, G. Scarpetta, S. Schäfer, F. Schönebeck, C. Snodgrass, J. Skottfelt, J. Surdej, J. Tregloan-Reed, O. Wertz
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  ABSTRACT: Aims: We present 11 high-precision photometric transit observations of the transiting super-Earth planet GJ1214b. Combining these data with observations from other authors, we investigate the ephemeris for possible signs of transit timing variations (TTVs) using a Bayesian approach. Methods: The observations were obtained using telescope-defocusing techniques, and achieve a high precision with random errors in the photometry as low as 1mmag per point. To investigate the possibility of TTVs in the light curve, we calculate the overall probability of a TTV signal using Bayesian methods. Results: The observations are used to determine the photometric parameters and the physical properties of the GJ1214 system. Our results are in good agreement with published values. Individual times of mid-transit are measured with uncertainties as low as 10s, allowing us to reduce the uncertainty in the orbital period by a factor of two. Conclusions: A Bayesian analysis reveals that it is highly improbable that the observed transit times is explained by TTV, when compared with the simpler alternative of a linear ephemeris.
  07/2012;