Examining the emission and transmission spectra of WASP-79b with retrieval 

2021 ◽  
Author(s):  
Michelle Bieger ◽  
Quentin Changeat

<p>Retrieval tools provide a way of determining an exoplanet atmosphere's temperature structure and composition with an observed planetary spectrum, working backwards to determine the chemistry and temperature by iteratively comparing synthetic spectra that have been constructed via a forward model to the observed spectra and determining a best-fit result (Barstow and Heng, 2020). This talk will be presenting the emission and reanalysed transmission spectrum and retrieval analysis of WASP-79b, an inflated hot Jupiter first detected by Smalley et al. (2012). Previous transmission spectra of WASP-79b has been analysed in Sozten et al. (2020), Skaf et al. (2020), and Rathcke et al. (2021); all studies agreeing on detections of H2O with various confidence levels, with the latter finding moderate evidence of an H- bound-free opacity compared to iron hydride abundance found by the other studies. Using the publicly available \verb+Iraclis+ data analysis pipeline and the Bayesian atmospheric retrieval framework TauREx 3, we will be adding to the global picture of this planet by examining the Hubble Space Telescope emission spectra as captured by the Wide Field Camera 3 G141 grism (PI: David Sing, proposal ID: 14767). </p>

2021 ◽  
Author(s):  
Lorenzo V. Mugnai ◽  
Darius Modirrousta-Galia ◽  
Billy Edwards ◽  

<p>We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (~500 K) Super-Earth (1.13 Re) that was obtained with the G141 grism (1.125 - 1.650 micron) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produce a precise transmission spectrum. We analysed the spectrum using the TauREx3 atmospheric retrieval code with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best-fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated envelope, a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints</p>


2020 ◽  
Author(s):  
Nour Skaf

<p>We would like to present the atmospheric characterisation of three large, gaseous planets: WASP-127b, WASP-79b and WASP-62b. We analysed spectroscopic data obtained with the G141 grism (1.088 - 1.68 um) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope (HST) using the Iraclis pipeline and the TauREx3 retrieval code, both of which are publicly available. For WASP-127b, which is the least dense planet discovered so far and is located in the short-period Neptune desert, our retrieval results found strong water absorption corresponding to an abundance of log(H$_2$O) = -2.71$^{+0.78}_{-1.05}$, and absorption compatible with an iron hydride abundance of log(FeH)=$-5.25^{+0.88}_{-1.10}$, with an extended cloudy atmosphere.<br />We also detected water vapour in the atmospheres of WASP-79b and WASP-62b, with best-fit models indicating the presence of iron hydride, too.<br />We used the Atmospheric Detectability Index (ADI) as well as Bayesian log evidence to quantify the strength of the detection and compared our results to the hot Jupiter population study by Tsiaras et al 2018.<br />While all the planets studied here are suitable targets for characterisation with upcoming facilities such as the James Webb Space Telescope (JWST) and Ariel, WASP-127b is of particular interest due to its low density, and a thorough atmospheric study would develop our understanding of planet formation and migration. </p>


2021 ◽  
Vol 923 (1) ◽  
pp. 101
Author(s):  
Jinhyub Kim ◽  
M. James Jee ◽  
John P. Hughes ◽  
Mijin Yoon ◽  
Kim HyeongHan ◽  
...  

Abstract We present an improved weak-lensing (WL) study of the high-z (z = 0.87) merging galaxy cluster ACT-CL J0102–4915 (“El Gordo”) based on new wide-field Hubble Space Telescope imaging data. The new imaging data cover the ∼3.5 × ∼3.5 Mpc region centered on the cluster and enable us to detect WL signals beyond the virial radius, which was not possible in previous studies. We confirm the binary mass structure consisting of the northwestern (NW) and southeastern (SE) subclusters and the ∼2σ dissociation between the SE mass peak and the X-ray cool core. We obtain the mass estimates of the subclusters by simultaneously fitting two Navarro–Frenk–White (NFW) halos without employing mass–concentration relations. The masses are M 200 c NW = 9.9 − 2.2 + 2.1 × 1014 and M 200 c SE = 6.5 − 1.4 + 1.9 × 1014 M ⊙ for the NW and SE subclusters, respectively. The mass ratio is consistent with our previous WL study but significantly different from the previous strong-lensing results. This discrepancy is attributed to the use of extrapolation in strong-lensing studies because the SE component possesses a higher concentration. By superposing the two best-fit NFW halos, we determine the total mass of El Gordo to be M 200 c = 2.13 − 0.23 + 0.25 × 1015 M ⊙, which is ∼23% lower than our previous WL result [M 200c = (2.76 ± 0.51) × 1015 M ⊙]. Our updated mass is a more direct measurement, since we are not extrapolating to R 200c as in all previous studies. The new mass is compatible with the current ΛCDM cosmology.


2020 ◽  
Author(s):  
Billy Edwards ◽  
Quentin Changeat ◽  
William Pluriel ◽  
Niall Whiteford ◽  
Kai Hou Yip ◽  
...  

<p>The Hubble Space Telescope’s Wide Field Camera 3 (WFC3) has been widely used for transmission and emission spectroscopy of exoplanet atmospheres, identifying the main molecular constituents, detecting the presence of clouds and probing their thermal structure. Hubble observations of the emission spectra of a number of ultra-hot Jupiters have led to somewhat surprising results. Initially, these very hot planets were predicted to have inverted temperature pressure profiles due to strong optical absorption by TiO/VO in the upper atmospheres. However, observations of their emission spectra have been inconclusive on their thermal structure and composition. While some datasets show rich spectral features, others can be fit with simple blackbody models.</p> <p>We will present the analysis of Hubble WFC3 transmission and emission spectra for two ultra-hot Jupiters: WASP-76 b and KELT-7 b. In each case, the data was reduced and fitted using the open-source codes Iraclis and Taurex3. Previous studies of the WFC3 transmission spectra of WASP-76 b found hints of TiO and VO or non-grey clouds. Accounting for a fainter stellar companion to WASP-76, we reanalyse this data and show that removing the effects of this background star changes the slope of the spectrum, resulting in these visible absorbers no longer being detected, removing the need for a non-grey cloud model to adequately fit the data but maintaining the strong water feature previously seen. However, our analysis of the emission spectrum suggests the presence of titanium oxide (TiO) and an atmospheric thermal inversion. Meanwhile, our study of KELT-7 b uncovers a rich transmission spectrum which suggests the presence of water and H-. In contrast, the extracted emission spectrum does not contain strong absorption features and, although it is not consistent with a simple blackbody, it can be explained by a varying temperature-pressure profile, collision induced absorption (CIA) and H-. </p> <p>These finding bring new insights into the nature of this intriguing class of planets but more data is required to fully understand them and thus we will also present the anticipated results of further characterisation.</p>


Author(s):  
S. Karpov ◽  
G. Beskin ◽  
A. Biryukov ◽  
S. Bondar ◽  
E. Ivanov ◽  
...  

Here we present the summary of operation of a novel 9-channel wide-field optical monitoring system with subsecond temporal resolution, Mini-MegaTORTORA, which systematically surveys the sky since 2014 at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (∼900 square degrees) or narrow (∼100 square degrees fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by Mini-MegaTORTORA also include faint meteors and artificial satellites. The imaging survey performed by Mini-MegaTORTORA also allows to look for a slower variability of various kinds of objects.


2020 ◽  
Vol 501 (1) ◽  
pp. 269-280
Author(s):  
Xuheng Ding ◽  
Tommaso Treu ◽  
Simon Birrer ◽  
Adriano Agnello ◽  
Dominique Sluse ◽  
...  

ABSTRACT One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ($\mathcal {M}_{\rm BH}$) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution.


2019 ◽  
Vol 24 (3) ◽  
pp. 213-223 ◽  
Author(s):  
Raimo Franke ◽  
Bettina Hinkelmann ◽  
Verena Fetz ◽  
Theresia Stradal ◽  
Florenz Sasse ◽  
...  

Mode of action (MoA) identification of bioactive compounds is very often a challenging and time-consuming task. We used a label-free kinetic profiling method based on an impedance readout to monitor the time-dependent cellular response profiles for the interaction of bioactive natural products and other small molecules with mammalian cells. Such approaches have been rarely used so far due to the lack of data mining tools to properly capture the characteristics of the impedance curves. We developed a data analysis pipeline for the xCELLigence Real-Time Cell Analysis detection platform to process the data, assess and score their reproducibility, and provide rank-based MoA predictions for a reference set of 60 bioactive compounds. The method can reveal additional, previously unknown targets, as exemplified by the identification of tubulin-destabilizing activities of the RNA synthesis inhibitor actinomycin D and the effects on DNA replication of vioprolide A. The data analysis pipeline is based on the statistical programming language R and is available to the scientific community through a GitHub repository.


Author(s):  
En-Kun Li ◽  
Minghui Du ◽  
Zhi-Huan Zhou ◽  
Hongchao Zhang ◽  
Lixin Xu

Abstract Using the fσ8(z) redshift space distortion (RSD) data, the $\sigma _8^0-\Omega _m^0$ tension is studied utilizing a parameterization of growth rate f(z) = Ωm(z)γ. Here, f(z) is derived from the expansion history H(z) which is reconstructed from the observational Hubble data applying the Gaussian Process method. It is found that different priors of H0 have great influences on the evolution curve of H(z) and the constraint of $\sigma _8^0-\Omega _m^0$. When using a larger H0 prior, the low redshifts H(z) deviate significantly from that of the ΛCDM model, which indicates that a dark energy model different from the cosmological constant can help to relax the H0 tension problem. The tension between our best-fit values of $\sigma _8^0-\Omega _m^0$ and that of the Planck 2018 ΛCDM (PLA) will disappear (less than 1σ) when taking a prior for H0 obtained from PLA. Moreover, the tension exceeds 2σ level when applying the prior H0 = 73.52 ± 1.62 km/s/Mpc resulted from the Hubble Space Telescope photometry. By comparing the $S_8 -\Omega _m^0$ planes of our method with the results from KV450+DES-Y1, we find that using our method and applying the RSD data may be helpful to break the parameter degeneracies.


2010 ◽  
Vol 6 (S274) ◽  
pp. 268-273
Author(s):  
N. Mandolesi ◽  
C. Burigana ◽  
A. Gruppuso ◽  
P. Procopio ◽  
S. Ricciardi

AbstractThis paper provides an overview of the ESA Planck mission and its scientific promises. Planck is equipped with a 1.5–m effective aperture telescope with two actively-cooled instruments observing the sky in nine frequency channels from 30 GHz to 857 GHz: the Low Frequency Instrument (LFI) operating at 20 K with pseudo-correlation radiometers, and the High Frequency Instrument (HFI) with bolometers operating at 100 mK. After the successful launch in May 2009, Planck has already mapped the sky twice (at the time of writing this review) with the expected behavior and it is planned to complete at least two further all-sky surveys. The first scientific results, consisting of an Early Release Compact Source Catalog (ERCSC) and in about twenty papers on instrument performance in flight, data analysis pipeline, and main astrophysical results, will be released on January 2011. The first publications of the main cosmological implications are expected in 2012.


2021 ◽  
Vol 923 (2) ◽  
pp. 278
Author(s):  
S. T. Linden ◽  
A. S. Evans ◽  
K. Larson ◽  
G. C. Privon ◽  
L. Armus ◽  
...  

Abstract We present the results of a Hubble Space Telescope WFC3 near-UV and Advanced Camera for Surveys Wide Field Channel optical study into the star cluster populations of a sample of 10 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. Through integrated broadband photometry we have derived ages, masses, and extinctions for a total of 1027 star clusters in galaxies with d L < 110 Mpc in order to avoid issues related to cluster bending. The measured cluster age distribution slope of dN / d τ ∝ τ − 0.5 + / − 0.12 is steeper than what has been observed in lower-luminosity star-forming galaxies. Further, differences in the slope of the observed cluster age distribution between inner- ( dN / d τ ∝ τ − 1.07 + / − 0.12 ) and outer-disk ( dN / d τ ∝ τ − 0.37 + / − 0.09 ) star clusters provide evidence of mass-dependent cluster destruction in the central regions of LIRGs driven primarily by the combined effect of strong tidal shocks and encounters with massive giant molecular clouds. Excluding the nuclear ring surrounding the Seyfert 1 nucleus in NGC 7469, the derived cluster mass function (CMF; dN / dM ∝ M α ) offers marginal evidence for a truncation in the power law at M t ∼ 2×106 M ⊙ for our three most cluster-rich sources, which are all classified as early stage mergers. Finally, we find evidence of a flattening of the CMF slope of dN / dM ∝ M − 1.42 ± 0.1 for clusters in late-stage mergers relative to early stage (α = −1.65 ± 0.02), which we attribute to an increase in the formation of massive clusters over the course of the interaction.


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