Deciphering the atmosphere of HAT-P-12b: solving discrepant results

Context. Two independent investigations of the atmosphere of the hot Jupiter HAT-P-12b by two different groups resulted in discrepant solutions. Using broad-band photometry from the ground, one study found a flat and featureless transmission spectrum that was interpreted as gray absorption by dense cloud coverage. The second study made use of Hubble Space Telescope (HST) observations and found Rayleigh scattering at optical wavelengths caused by haze. Aims. The main purpose of this work is to determine the source of this inconsistency and provide feedback to prevent similar discrepancies in future analyses of other exoplanetary atmospheres. Methods. We studied the observed discrepancy via two methods. With further broad-band observations in the optical wavelength regions, we strengthened the previous measurements in precision, and with a homogeneous reanalysis of the published data, we were able to assess the systematic errors and the independent analyses of the two different groups. Results. Repeating the analysis steps of both works, we found that deviating values for the orbital parameters are the reason for the aforementioned discrepancy. Our work showed a degeneracy of the planetary spectral slope with these parameters. In a homogeneous reanalysis of all data, the two literature data sets and the new observations converge to a consistent transmission spectrum, showing a low-amplitude spectral slope and a tentative detection of potassium absorption.

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The GTC exoplanet transit spectroscopy survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834063 ◽

2019 ◽

Vol 622 ◽

pp. A172 ◽

Cited By ~ 7

Author(s):

F. Murgas ◽

G. Chen ◽

E. Pallé ◽

L. Nortmann ◽

G. Nowak

Keyword(s):

Transmission Spectrum ◽

Rayleigh Scattering ◽

Extrasolar Planets ◽

Light Curves ◽

Data Sets ◽

Transmission Spectra ◽

Data Set ◽

Systematic Effects ◽

The Individual ◽

Spectrum Slope

Context. Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected using ground- or space-based telescopes. However, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this phenomena is key to our correct interpretation of exoplanet atmospheric properties. Aims. We use the ten-meter Gran Telescopio Canarias (GTC) telescope to carry out a ground-based transmission spectra survey of extrasolar planets to characterize their atmospheres. In this paper we investigate the exoplanet HAT-P-11b, a Neptune-sized planet orbiting an active K-type star. Methods. We obtained long-slit optical spectroscopy of two transits of HAT-P-11b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) on August 30, 2016 and September 25, 2017. We integrated the spectrum of HAT-P-11 and one reference star in several spectroscopic channels across the λ ~ 400–785 nm region, creating numerous light curves of the transits. We fit analytic transit curves to the data taking into account the systematic effects and red noise present in the time series in an effort to measure the change of the planet-to-star radius ratio (Rp∕Rs) across wavelength. Results. By fitting both transits together, we find a slope in the transmission spectrum showing an increase of the planetary radius towards blue wavelengths. Closer inspection of the transmission spectrum of the individual data sets reveals that the first transit presents this slope while the transmission spectrum of the second data set is flat. Additionally, we detect hints of Na absorption on the first night, but not on the second. We conclude that the transmission spectrum slope and Na absorption excess found in the first transit observation are caused by unocculted stellar spots. Modeling the contribution of unocculted spots to reproduce the results of the first night we find a spot filling factor of δ = 0.62−0.17+0.20 and a spot-to-photosphere temperature difference of ΔT = 429−299+184 K.

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Ground-based transmission spectroscopy with FORS2: A featureless optical transmission spectrum and detection of H2O for the ultra-hot Jupiter WASP-103b

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2307 ◽

2020 ◽

Vol 497 (4) ◽

pp. 5155-5170 ◽

Cited By ~ 1

Author(s):

Jamie Wilson ◽

Neale P Gibson ◽

Nikolay Nikolov ◽

Savvas Constantinou ◽

Nikku Madhusudhan ◽

...

Keyword(s):

Transmission Spectrum ◽

Rayleigh Scattering ◽

Full Range ◽

Broad Band ◽

Light Curves ◽

Small Scale ◽

Correlated Noise ◽

Transmission Spectroscopy ◽

Short Period ◽

Hot Jupiter

ABSTRACT We report ground-based transmission spectroscopy of the highly irradiated and ultra-short period hot-Jupiter WASP-103b covering the wavelength range ≈400–600 nm using the FORS2 instrument on the Very Large Telescope. The light curves show significant time-correlated noise which is mainly invariant in wavelength and which we model using a Gaussian process. The precision of our transmission spectrum is improved by applying a common-mode correction derived from the white light curve, reaching typical uncertainties in transit depth of ≈2 × 10−4 in wavelength bins of 15 nm. After correction for flux contamination from a blended companion star, our observations reveal a featureless spectrum across the full range of the FORS2 observations and we are unable to confirm the Na absorption previously inferred using Gemini/GMOS or the strong Rayleigh scattering observed using broad-band light curves. We performed a Bayesian atmospheric retrieval on the full optical-infrared transmission spectrum using the additional data from Gemini/GMOS, HST/WFC3, and Spitzer observations and recover evidence for H2O absorption at the 4.0 σ level. However, our observations are not able to completely rule out the presence of Na, which is found at 2.0 σ in our retrievals. This may in part be explained by patchy/inhomogeneous clouds or hazes damping any absorption features in our FORS2 spectrum, but an inherently small scale height also makes this feature challenging to probe from the ground. Our results none the less demonstrate the continuing potential of ground-based observations for investigating exoplanet atmospheres and emphasize the need for the application of consistent and robust statistical techniques to low-resolution spectra in the presence of instrumental systematics.

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The GTC exoplanet transit spectroscopy survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731113 ◽

2018 ◽

Vol 609 ◽

pp. A33 ◽

Cited By ~ 5

Author(s):

H. Parviainen ◽

E. Pallé ◽

G. Chen ◽

L. Nortmann ◽

F. Murgas ◽

...

Keyword(s):

High Altitude ◽

Transmission Spectrum ◽

Rayleigh Scattering ◽

Equilibrium Temperature ◽

Transmission Spectra ◽

Spectroscopy Analysis ◽

Orbital Parameters ◽

Transmission Spectroscopy ◽

The Common ◽

20 Nm

Aims. We set out to study the atmosphere of WASP-80b, a warm inflated gas giant with an equilibrium temperature of ~800 K, using ground-based transmission spectroscopy covering the spectral range from 520 to 910 nm. The observations allow us to probe the existence and abundance of K and Na in WASP-80b’s atmosphere, existence of high-altitude clouds, and Rayleigh-scattering in the blue end of the spectrum. Methods. We observed two spectroscopic time series of WASP-80b transits with the OSIRIS spectrograph installed in the Gran Telescopio Canarias (GTC), and use the observations to estimate the planet’s transmission spectrum between 520 nm and 910 nm in 20 nm-wide passbands, and around the K I and Na I resonance doublets in 6 nm-wide passbands. We jointly model three previously published broadband datasets consisting of 27 light curves, prior to a transmission spectroscopy analysis in order to obtain improved estimates of the planet’s orbital parameters, average radius ratio, and stellar density. The parameter posteriors from the broadband analysis are used to set informative priors on the transmission spectroscopy analysis. The final transmission spectroscopy analyses are carried out jointly for the two nights using a divide-by-white approach to remove the common-mode systematics, and Gaussian processes to model the residual wavelength-dependent systematics. Results. We recover a flat transmission spectrum with no evidence of Rayleigh scattering or K I or Na I absorption, and obtain an improved system characterisation as a by-product of the broadband- and GTC-dataset modelling. The transmission spectra estimated separately from the two observing runs are consistent with each other, as are the transmission spectra estimated using either a parametric or nonparametric systematics model. The flat transmission spectrum favours an atmosphere model with high-altitude clouds over cloud-free models with stellar or sub-stellar metallicities. Conclusions. Our results disagree with the recently published discovery of strong K I absorption in WASP-80b’s atmosphere based on ground-based transmission spectroscopy with FORS2 at VLT.

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The Sampling Distribution of Disease-Associated Alleles

Genetics ◽

10.1093/genetics/147.4.1855 ◽

1997 ◽

Vol 147 (4) ◽

pp. 1855-1861 ◽

Cited By ~ 1

Author(s):

Montgomery Slatkin ◽

Bruce Rannala

Keyword(s):

Low Frequency ◽

Null Model ◽

Sampling Distribution ◽

Death Process ◽

Published Data ◽

Data Sets ◽

Likelihood Functions ◽

Alternative Hypotheses ◽

Size Standard ◽

Birth Death

Abstract A theory is developed that provides the sampling distribution of low frequency alleles at a single locus under the assumption that each allele is the result of a unique mutation. The numbers of copies of each allele is assumed to follow a linear birth-death process with sampling. If the population is of constant size, standard results from theory of birth-death processes show that the distribution of numbers of copies of each allele is logarithmic and that the joint distribution of numbers of copies of k alleles found in a sample of size n follows the Ewens sampling distribution. If the population from which the sample was obtained was increasing in size, if there are different selective classes of alleles, or if there are differences in penetrance among alleles, the Ewens distribution no longer applies. Likelihood functions for a given set of observations are obtained under different alternative hypotheses. These results are applied to published data from the BRCA1 locus (associated with early onset breast cancer) and the factor VIII locus (associated with hemophilia A) in humans. In both cases, the sampling distribution of alleles allows rejection of the null hypothesis, but relatively small deviations from the null model can account for the data. In particular, roughly the same population growth rate appears consistent with both data sets.

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Relative testis size and mating systems in anurans: large testis in multiple-male mating in foam-nesting frogs

Animal Biology ◽

10.1163/157075511x570312 ◽

2011 ◽

Vol 61 (2) ◽

pp. 225-238 ◽

Cited By ~ 15

Author(s):

Wen Bo Liao ◽

Zhi Ping Mi ◽

Cai Quan Zhou ◽

Ling Jin ◽

Xian Han ◽

...

Keyword(s):

Sperm Competition ◽

Published Data ◽

Male Mating ◽

Data Sets ◽

Testis Size ◽

Data Set ◽

Monogamous Species ◽

Large Testis ◽

Testes Size ◽

Testis Mass

AbstractComparative studies of the relative testes size in animals show that promiscuous species have relatively larger testes than monogamous species. Sperm competition favours the evolution of larger ejaculates in many animals – they give bigger testes. In the view, we presented data on relative testis mass for 17 Chinese species including 3 polyandrous species. We analyzed relative testis mass within the Chinese data set and combining those data with published data sets on Japanese and African frogs. We found that polyandrous foam nesting species have relatively large testes, suggesting that sperm competition was an important factor affecting the evolution of relative testes size. For 4 polyandrous species testes mass is positively correlated with intensity (males/mating) but not with risk (frequency of polyandrous matings) of sperm competition.

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Children with 5′-end NF1 gene mutations are more likely to have glioma

Neurology Genetics ◽

10.1212/nxg.0000000000000192 ◽

2017 ◽

Vol 3 (5) ◽

pp. e192 ◽

Cited By ~ 12

Author(s):

Corina Anastasaki ◽

Stephanie M. Morris ◽

Feng Gao ◽

David H. Gutmann

Keyword(s):

Gene Mutation ◽

Statistical Significance ◽

Gene Mutations ◽

Neurofibromatosis Type ◽

Published Data ◽

Data Sets ◽

Nonsense Mutations ◽

Data Set ◽

Nf1 Gene ◽

The Relationship

Objective:To ascertain the relationship between the germline NF1 gene mutation and glioma development in patients with neurofibromatosis type 1 (NF1).Methods:The relationship between the type and location of the germline NF1 mutation and the presence of a glioma was analyzed in 37 participants with NF1 from one institution (Washington University School of Medicine [WUSM]) with a clinical diagnosis of NF1. Odds ratios (ORs) were calculated using both unadjusted and weighted analyses of this data set in combination with 4 previously published data sets.Results:While no statistical significance was observed between the location and type of the NF1 mutation and glioma in the WUSM cohort, power calculations revealed that a sample size of 307 participants would be required to determine the predictive value of the position or type of the NF1 gene mutation. Combining our data set with 4 previously published data sets (n = 310), children with glioma were found to be more likely to harbor 5′-end gene mutations (OR = 2; p = 0.006). Moreover, while not clinically predictive due to insufficient sensitivity and specificity, this association with glioma was stronger for participants with 5′-end truncating (OR = 2.32; p = 0.005) or 5′-end nonsense (OR = 3.93; p = 0.005) mutations relative to those without glioma.Conclusions:Individuals with NF1 and glioma are more likely to harbor nonsense mutations in the 5′ end of the NF1 gene, suggesting that the NF1 mutation may be one predictive factor for glioma in this at-risk population.

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Structure in parasite component communities in wild rodents: predictability, stability, associations and interactions .... or pure randomness?

Parasitology ◽

10.1017/s0031182008000334 ◽

2008 ◽

Vol 135 (7) ◽

pp. 751-766 ◽

Cited By ~ 42

Author(s):

J. M. BEHNKE

Keyword(s):

Species Richness ◽

Published Data ◽

Data Sets ◽

Wild Rodents ◽

Heligmosomoides Polygyrus ◽

Wood Mice ◽

Core Species ◽

Helminth Communities ◽

Immune Mediated ◽

Concurrent Infections

SUMMARYExperimental data establish that interactions exist between species of intestinal helminths during concurrent infections in rodents, the strongest effects being mediated through the host's immune responses. Detecting immune-mediated relationships in wild rodent populations has been fraught with problems and published data do not support a major role for interactions in structuring helminth communities. Helminths in wild rodents show predictable patterns of seasonal, host age-dependent and spatial variation in species richness and in abundance of core species. When these are controlled for, patterns of co-infection compatible with synergistic interactions can be demonstrated. At least one of these, the positive relationship betweenHeligmosomoides polygyrusand species richness of other helminths has been demonstrated in three totally independent data-sets. Collectively, they explain only a small percentage of the variance/deviance in abundance data and at this level are unlikely to play a major role in structuring helminth communities, although they may be important in the more heavily infected wood mice. Current worm burdens underestimate the possibility that earlier interactions through the immune system have taken place, and therefore interactions may have a greater role to play than is immediately evident from current worm burdens. Longitudinal studies are proposed to resolve this issue.

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Systematic and ontology-based approach to interoperable cross-domain open government data services

Transforming Government People Process and Policy ◽

10.1108/tg-08-2021-0132 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Hadi Masoumi ◽

Bahar Farahani ◽

Fereidoon Shams Aliee

Keyword(s):

Social Innovation ◽

Open Government ◽

Published Data ◽

Data Sets ◽

Full Potential ◽

Top Down ◽

Content Type ◽

Data Services ◽

Open Government Data ◽

Government Data

Purpose Open government data (OGD) has emerged as a radical paradigm shift and endeavor among government administrations across the world mainly due to its promises of transparency, accountability, public-private collaboration, civic participation, social innovation and data-driven value creation. Complexity, cross-cutting nature, diversity of data sets, interoperability and quality issues usually hamper unlocking the full potential value of data. To tackle these challenges, this paper aims to provide a novel solution using a top-down approach. Design/methodology/approach In this paper, the authors propose a systematic ontology-based approach combined with a novel architecture and its corresponding processes enabling organizations to carry out all the steps in the OGD value chain. In addition, an OGD Platform including a portal (www.iranopendata.ir) and a data management system (www.ogdms.iranopendata.ir) are developed to showcase the proposed solution. Findings The efficiency and the applicability of the solution are evaluated by a real-life use case on energy consumption of the buildings of the city of Tehran, Iran. Finally, a comparison was made with existing solutions, and the results show the proposed approach is able to address the existing gaps in the literature. Originality/value The results imply that modeling and designing the data model, as well as exploiting an ontology-based approach are critical pillars to create rich, relevant and well-described OGD data sets. Moreover, clarity on processes, roles and responsibilities are the key factors influencing the quality of the published data services. Thus, to the best of the knowledge, this is the first study that exploits and considers an ontology-based approach in a top-down manner to create OGD data sets.

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Mobile Robotic Sensors for Environmental Monitoring using Gaussian Markov Random Field

Robotica ◽

10.1017/s026357472000079x ◽

2020 ◽

pp. 1-23

Author(s):

Linh Nguyen ◽

Sarath Kodagoda ◽

Ravindra Ranasinghe ◽

Gamini Dissanayake

Keyword(s):

Random Field ◽

Markov Random Field ◽

Adaptive Sampling ◽

Published Data ◽

Data Sets ◽

Independence Property ◽

Gaussian Markov Random Field ◽

Markov Random ◽

Sampling Optimization ◽

Robotic Sensors

SUMMARY This paper addresses the issue of monitoring spatial environmental phenomena of interest utilizing information collected by a network of mobile, wireless, and noisy sensors that can take discrete measurements as they navigate through the environment. It is proposed to employ Gaussian Markov random field (GMRF) represented on an irregular discrete lattice by using the stochastic partial differential equations method to model the physical spatial field. It then derives a GMRF-based approach to effectively predict the field at unmeasured locations, given available observations, in both centralized and distributed manners. Furthermore, a novel but efficient optimality criterion is then proposed to design centralized and distributed adaptive sampling strategies for the mobile robotic sensors to find the most informative sampling paths in taking future measurements. By taking advantage of conditional independence property in the GMRF, the adaptive sampling optimization problem is proven to be resolved in a deterministic time. The effectiveness of the proposed approach is compared and demonstrated using pre-published data sets with appealing results.

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Atacama Compact Array observations of the pulsar-wind nebula of SNR 0540-69.3

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1675 ◽

2020 ◽

Vol 496 (2) ◽

pp. 1834-1844

Author(s):

P Lundqvist ◽

N Lundqvist ◽

C Vlahakis ◽

C-I Björnsson ◽

J R Dickel ◽

...

Keyword(s):

Spectral Index ◽

Supernova Remnant ◽

Broad Band ◽

Line Emission ◽

Published Data ◽

Strong Emission ◽

Band Filter ◽

Pulsar Wind ◽

Infrared Data ◽

Compact Array

ABSTRACT We present observations of the pulsar-wind nebula (PWN) region of SNR 0540-69.3. The observations were made with the Atacama Compact Array (ACA) in Bands 4 and 6. We also add radio observations from the Australia Compact Array at 3 cm. For 1.449–233.50 GHz, we obtain a synchrotron spectrum $F_{\nu } \propto \nu ^{-\alpha _{\nu }}$, with the spectral index αν = 0.17 ± 0.02. To conclude how this joins the synchrotron spectrum at higher frequencies, we include hitherto unpublished AKARI mid-infrared data, and evaluate published data in the ultraviolet (UV), optical, and infrared (IR). In particular, some broad-band filter data in the optical must be discarded from our analysis due to contamination by spectral line emission. For the UV/IR part of the synchrotron spectrum, we arrive at $\alpha _{\nu } = 0.87^{+0.08}_{-0.10}$. There is room for 2.5 × 10−3 M⊙ of dust with a temperature of ∼55 K if there are dual breaks in the synchrotron spectrum, one around ∼9 × 1010 Hz and another at ∼2 × 1013 Hz. The spectral index then changes at ∼9 × 1010 Hz from αν = 0.14 ± 0.07 in the radio to $\alpha _{\nu } = 0.35^{-0.07}_{+0.05}$ in the millimetre-to-far-IR range. The ACA Band 6 data marginally resolve the PWN. In particular, the strong emission $\text{$\sim$} 1\hbox{$.\!\!^{\prime \prime }$}5$ south-west of the pulsar, seen at other wavelengths, and resolved in the 3 cm data with its 0.″8 spatial resolution, is also strong in the millimetre range. The ACA data clearly reveal the supernova remnant shell ∼20–35 arcsec west of the pulsar, and for the shell we derive αν = 0.64 ± 0.05 for the range 8.6–145 GHz.

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