The James Webb Space Telescope (JWST ) is expected to revolutionize our understanding of Jovian worlds over the coming decade. However, as we push towards characterizing cooler, smaller, "terrestrial-like" planets, dedicated next-generation facilities will be required to tease out the small spectral signatures indicative of biological activity. Here, we evaluate the feasibility of determining atmospheric properties, from near-to-mid-infrared transmission spectra, of transiting temperate terrestrial M-dwarf companions. Specifically, we utilize atmospheric retrievals to explore the trade space between spectral resolution, wavelength coverage, and signal-to-noise on our ability to both detect molecular species and constrain their abundances. We find that increasing spectral resolution beyond R=100 for near-infrared wavelengths, shorter than 5µm, proves to reduce the degeneracy between spectral features of different molecules and thus greatly benefits the abundance constraints. However, this benefit is greatly diminished beyond 5µm as any overlap between broad features in the mid-infrared does not deconvolve with higher resolutions. Additionally, our findings revealed that the inclusion of features beyond 11µm did not meaningfully improve the detection significance nor abundance constraints results. We conclude that an instrument with continuous wavelength coverage from ∼2-11µm, spectral resolution of R 50-300, and a 25m 2 collecting area, would be capable of detecting H 2 O, CO 2 , CH 4 , O 3 , and N 2 O in the atmosphere of an Earth-analog transiting a M-dwarf (mag K = 8.0) within 50 transits, and obtain better than an order-of-magnitude constraint on each of their abundances.
Based on current models of the Cosmic X-ray Background (CXB), heavily obscured Active Galactic Nuclei (AGN) are expected to make up ∼ 10% of the peak emission of the CXB and ∼ 20% of the total population of AGN, yet few of these sources have been recorded and characterized in current surveys. Here we present the Chandra follow-up observation of 14 AGN detected by Swift-BAT. For five sources in the sample, NuSTAR observations in the 3-80 keV band are also available. The X-ray spectral fitting over the 0.3-150 keV energy range allows us to determine the main X-ray spectral parameters, such as the photon index and the intrinsic absorption, of these objects, and to make hypotheses on the physical structures responsible for the observed spectra. We find that 13 of the 14 objects are absorbed AGN, and one is a candidate Compton thick AGN, having intrinsic absorption N H > 10 24 cm −2 . Finally, we verified that the use of NuSTAR observations is strategic to strongly constrain the properties of obscured AGN, since the best-fit values we obtained for parameters such as the power-law photon index Γ and the intrinsic absorption N H changed sometimes significantly fitting the spectra with and without the use of NuSTAR data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.