Blind source separation techniques are used to reanalyze two exoplanetary transit light curves of the exoplanet HD 189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6 ...mum during the "cold" era. These observations, together with observations at other IR wavelengths, are crucial to characterize the atmosphere of the planet HD 189733b. Previous analyses of the same data sets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent way is novel in the literature. The advantage of our reanalyses over previous work is that we do not have to make any assumptions on the structure of the unknown instrumental systematics. Such "admission of ignorance" may result in larger error bars than reported in the literature, up to a factor 1.6. This is a worthwhile tradeoff for much higher objectivity, necessary for trustworthy claims. Our main results are (1) improved and robust values of orbital and stellar parameters, (2) new measurements of the transit depths at 3.6 mum, (3) consistency between the parameters estimated from the two observations, (4) repeatability of the measurement within the photometric level of ~2 x 10 super(-4) in the IR, and (5) no evidence of stellar variability at the same photometric level within one year.
Performance of μ-RWELL detector vs resistivity of the resistive stage Bencivenni, G.; De Oliveira, R.; Felici, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2018, Letnik:
886
Journal Article
Recenzirano
Odprti dostop
The μ-RWELL is a compact spark-protected single amplification stage Micro-Pattern-Gaseous-Detector (MPGD). The detector amplification stage is realized with a polyimide structure, micro-patterned ...with a dense matrix of blind-holes, integrated into the readout structure. The anode is formed by a thin Diamond Like Carbon (DLC) resistive layer separated by an insulating glue layer from the readout strips. The introduction of the resistive layer strongly suppressing the transition from streamer to spark gives the possibility to achieve large gains (> 104), without significantly affecting the capability to be efficiently operated in high particle fluxes. In this work we present the results of a systematic study of the μ-RWELL performance as a function of the DLC resistivity. The tests have been performed either with collimated 5.9 keV X-rays or with pion and muon beams at the SPS Secondary Beamline H4 and H8 at CERN.
Atmospheres of highly irradiated gas giant planets host a large variety of atomic and ionic species. Here we observe the thermal emission spectra of the two ultra-hot Jupiters WASP-33b and ...KELT-20b/MASCARA-2b in the near-infrared wavelength range with CARMENES. Via high-resolution Doppler spectroscopy, we searched for neutral silicon (Si) in their dayside atmospheres. We detect the Si spectral signature of both planets via cross-correlation with model spectra. Detection levels of 4.8
σ
and 5.4
σ
, respectively, are observed when assuming a solar atmospheric composition. This is the first detection of Si in exoplanet atmospheres. The presence of Si is an important finding due to its fundamental role in cloud formation and, hence, for the planetary energy balance. Since the spectral lines are detected in emission, our results also confirm the presence of an inverted temperature profile in the dayside atmospheres of both planets.
Bacterial contamination of blood components remains a major challenge in transfusion medicine, particularly, platelet concentrates (PCs) due to the storage conditions that support bacterial ...proliferation. In this study, we develop a rapid, sensitive and specific real-time PCR protocol for bacterial screening of PCs. An internally controlled real-time PCR-based method was optimized and validated with our proprietary 16S Universal PCR Master Mix (IBMP/Fiocruz), which targets a conserved region of the bacterial 16S rRNA gene. Nonspecific background DNA was completely eliminated by treating the PCR Master Mix with ethidium monoazide (EMA). A lower limit of detection was observed for 10 genome equivalents with an observed Ct value of 34±1.07 in calibration curve generated with 10-fold serial dilutions of E. coli DNA. The turnaround time for processing, including microbial DNA purification, was approximately 4 hours. The developed method showed a high sensitivity with no non-specific amplification and a lower time-to-detection than traditional microbiological methods, demonstrating it to be an efficient means of screening pre-transfusion PCs.
High space resolution μ-RWELL for high particle rate Bencivenni, G.; De Oliveira, R.; Felici, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Odprti dostop
The μ-RWELL is a single-amplification stage resistive MPGD. The amplification element, realized on a polyimide foil micro-patterned with a high density blind-holes (wells), is embedded through a thin ...resistive film, in the readout PCB. The introduction of the resistive layer affects the charge spread on the readout electrodes and suppresses the transition from streamer to spark giving the possibility to achieve large gains (>104). As a drawback the capability to stand high particle fluxes is reduced. In order to get rid of such a limitation different resistive layouts with prompt current evacuation schemes have been designed. In this work we present the study of the performance of the high rate layouts done at PSI, together with the measurement of the space resolution for orthogonal and inclined tracks performed at CERN.
The μ-RWELL is a new generation Micro-Pattern Gaseous Detector, composed of two elements: the cathode and the μ-RWELL_PCB including the amplification stage, realized with a polyimide structure ...micro-patterned with a blind-hole matrix, embedded through a Diamond-Like Carbon (DLC) resistive layer with the readout PCB. Different layouts of the resistive stage have been studied: the simplest one is based on a single DLC layer with edge grounding, suitable for low rate applications (30–40 kHz/cm2). More sophisticated schemes are under study for high-rate purposes (up to 2–3 MHz/cm2) in order to optimize the performance and the constructive process. For the phase-2 upgrade of the LHCb muon detector the experiment is targeting a luminosity of 2×1034 cm−2 s−1, with strong requirements on the robustness and detection efficiency of the muon system. We report on the ongoing R&D, showing also the latest measured performances of the new high-rate versions of the detector.
Multiband photometric transit observations or low-resolution spectroscopy (spectro-photometry) are normally used to retrieve the broadband transmission spectra of transiting exoplanets in order to ...assess the chemical composition of their atmospheres. In this paper we present an alternative approach for recovering the broadband transmission spectra using chromatic Doppler tomography based on physical modeling through the
SOAP
tool: CHOCOLATE (CHrOmatiC line prOfiLe tomogrAphy TEchnique). To validate the method and examine its performance, we use observational data recently obtained with the ESPRESSO instrument to retrieve the transmission spectra of the archetypal hot Jupiter HD 209458b. Our findings indicate that the recovered transmission spectrum is in good agreement with the results presented in previous studies, which used different methodologies to extract the spectrum, achieving similar precision. We explored several atmospheric models and inferred from spectral retrieval that a model containing H
2
O and NH
3
is the preferred scenario. The CHOCOLATE methodology is particularly interesting for future studies of exoplanets around young and active stars or moderate to fast rotating stars, considering
SOAP
’s ability to model stellar active regions and the fact that the rotational broadening of spectral lines favors its application. Furthermore, CHOCOLATE will allow the broad transmission spectrum of a planet to be retrieved using high-S/N, high-resolution spectroscopy with the next generation of extremely large telescopes, where low-resolution spectroscopy will not always be accessible.
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