17 research outputs found
BEER analysis of Kepler and CoRoT light curves: I. Discovery of Kepler-76b: A hot Jupiter with evidence for superrotation
We present the first case in which the BEER algorithm identified a hot
Jupiter in the Kepler light curve, and its reality was confirmed by orbital
solutions based on follow-up spectroscopy. The companion Kepler-76b was
identified by the BEER algorithm, which detected the BEaming (sometimes called
Doppler boosting) effect together with the Ellipsoidal and Reflection/emission
modulations (BEER), at an orbital period of 1.54 days, suggesting a planetary
companion orbiting the 13.3 mag F star. Further investigation revealed that
this star appeared in the Kepler eclipsing binary catalog with estimated
primary and secondary eclipse depths of 5e-3 and 1e-4 respectively.
Spectroscopic radial-velocity follow-up observations with TRES and SOPHIE
confirmed Kepler-76b as a transiting 2.0+/-0.26 Mjup hot Jupiter. The mass of a
transiting planet can be estimated from either the beaming or the ellipsoidal
amplitude. The ellipsoidal-based mass estimate of Kepler-76b is consistent with
the spectroscopically measured mass while the beaming-based estimate is
significantly inflated. We explain this apparent discrepancy as evidence for
the superrotation phenomenon, which involves eastward displacement of the
hottest atmospheric spot of a tidally-locked planet by an equatorial
super-rotating jet stream. This phenomenon was previously observed only for HD
189733b in the infrared. We show that a phase shift of 10.3+/-2.0 degrees of
the planet reflection/emission modulation, due to superrotation, explains the
apparently inflated beaming modulation, resolving the ellipsoidal/beaming
amplitude discrepancy. Kepler-76b is one of very few confirmed planets in the
Kepler light curves that show BEER modulations and the first to show
superrotation evidence in the Kepler band. Its discovery illustrates for the
first time the ability of the BEER algorithm to detect short-period planets and
brown dwarfs.Comment: 28 pages, 6 tables and 7 figures. Planet name changed to Kepler-76b.
Accepted for publication in the Astrophysical Journa
HAT-P-9b: A Low Density Planet Transiting a Moderately Faint F star
We report the discovery of a planet transiting a moderately faint (V=12.3
mag) late F star, with an orbital period of 3.92289 +/- 0.00004 days. From the
transit light curve and radial velocity measurements we determine that the
radius of the planet is R_p = 1.40 +/- 0.06 R_Jup and that the mass is M_p =
0.78 +/- 0.09 M_Jup. The density of the new planet, rho = 0.35 +/- 0.06 g
cm^{-3}, fits to the low-density tail of the currently known transiting
planets. We find that the center of transit is at T_c = 2454417.9077 +/- 0.0003
(HJD), and the total transit duration is 0.143 +/- 0.004 days. The host star
has M_s = 1.28 +/- 0.13 M_Sun and R_s = 1.32 +/- 0.07 R_Sun.Comment: Submitted to ApJ; V2: Replaced with accepted versio
CfA4: Light Curves for 94 Type Ia Supernovae
We present multi-band optical photometry of 94 spectroscopically-confirmed
Type Ia supernovae (SN Ia) in the redshift range 0.0055 to 0.073, obtained
between 2006 and 2011. There are a total of 5522 light curve points. We show
that our natural system SN photometry has a precision of roughly 0.03 mag or
better in BVr'i', 0.06 mag in u', and 0.07 mag in U for points brighter than
17.5 mag and estimate that it has a systematic uncertainty of 0.014, 0.010,
0.012, 0.014, 0.046, and 0.073 mag in BVr'i'u'U, respectively. Comparisons of
our standard system photometry with published SN Ia light curves and comparison
stars reveal mean agreement across samples in the range of ~0.00-0.03 mag. We
discuss the recent measurements of our telescope-plus-detector throughput by
direct monochromatic illumination by Cramer et al (in prep.). This technique
measures the whole optical path through the telescope, auxiliary optics,
filters, and detector under the same conditions used to make SN measurements.
Extremely well-characterized natural-system passbands (both in wavelength and
over time) are crucial for the next generation of SN Ia photometry to reach the
0.01 mag accuracy level. The current sample of low-z SN Ia is now sufficiently
large to remove most of the statistical sampling error from the dark energy
error budget. But pursuing the dark-energy systematic errors by determining
highly-accurate detector passbands, combining optical and near-infrared (NIR)
photometry and spectra, using the nearby sample to illuminate the population
properties of SN Ia, and measuring the local departures from the Hubble flow
will benefit from larger, carefully measured nearby samples.Comment: 43 page
Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts based on Metagenomic Gene Abundance
Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB) were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI) were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e.g. human metabolism, health and behaviour, as well as to understand the genetic link between host and microbiome
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
Harps-N: the new planet hunter at TNG
The Telescopio Nazionale Galileo (TNG)[9] hosts, starting in April 2012, the visible spectrograph HARPS-N. It is based on the design of its predecessor working at ESO's 3.6m telescope, achieving unprecedented results on radial velocity measurements of extrasolar planetary systems. The spectrograph's ultra-stable environment, in a temperature-controlled vacuum chamber, will allow measurements under 1 m/s which will enable the characterization of rocky, Earth-like planets. Enhancements from the original HARPS include better scrambling using octagonal section fibers with a shorter length, as well as a native tip-tilt system to increase image sharpness, and an integrated pipeline providing a complete set of parameters. Observations in the Kepler field will be the main goal of HARPS-N, and a substantial fraction of TNG observing time will be devoted to this follow-up. The operation process of the observatory has been updated, from scheduling constraints to telescope control system. Here we describe the entire instrument, along with the results from the first technical commissioning
Harps-N: the new planet hunter at TNG
The Telescopio Nazionale Galileo (TNG)[9] hosts, starting in April 2012, the visible spectrograph HARPS-N. It is based on the design of its predecessor working at ESO's 3.6m telescope, achieving unprecedented results on radial velocity measurements of extrasolar planetary systems. The spectrograph's ultra-stable environment, in a temperature-controlled vacuum chamber, will allow measurements under 1 m/s which will enable the characterization of rocky, Earth-like planets. Enhancements from the original HARPS include better scrambling using octagonal section fibers with a shorter length, as well as a native tip-tilt system to increase image sharpness, and an integrated pipeline providing a complete set of parameters. Observations in the Kepler field will be the main goal of HARPS-N, and a substantial fraction of TNG observing time will be devoted to this follow-up. The operation process of the observatory has been updated, from scheduling constraints to telescope control system. Here we describe the entire instrument, along with the results from the first technical commissioning