| 1. |
- Albert, Damien, et al.
(författare)
-
A Decade with VAMDC : Results and Ambitions
- 2020
-
Ingår i: Atoms. - : MDPI. - 2218-2004. ; 8:4
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an overview of the current status of the Virtual Atomic and Molecular Data Centre (VAMDC) e-infrastructure, including the current status of the VAMDC-connected (or to be connected) databases, updates on the latest technological development within the infrastructure and a presentation of some application tools that make use of the VAMDC e-infrastructure. We analyse the past 10 years of VAMDC development and operation, and assess their impact both on the field of atomic and molecular (A&M) physics itself and on heterogeneous data management in international cooperation. The highly sophisticated VAMDC infrastructure and the related databases developed over this long term make them a perfect resource of sustainable data for future applications in many fields of research. However, we also discuss the current limitations that prevent VAMDC from becoming the main publishing platform and the main source of A&M data for user communities, and present possible solutions under investigation by the consortium. Several user application examples are presented, illustrating the benefits of VAMDC in current research applications, which often need the A&M data from more than one database. Finally, we present our vision for the future of VAMDC.
|
|
| 2. |
- Arnadottir, Anna, et al.
(författare)
-
The Meridian S02E03 : Instrumentation & an Aussie encounter
- 2022
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- In this third episode of the second season Nic and Rebeca chat about equality in science before inviting Nikolai Piskunov to the microphone. Nikolai is a professor at the Department of Physics and Astronomy at Uppsala University. He was visiting Lund Observatory to give a talk about high-resolution transit spectroscopy and graciously agreed to make an appearance on the podcast.This season we are also bringing you some field reporting from the Nordic Optical Telescope on La Palma, where a team of astronomers are trying to catch an ultra-hot Jupiter-sized exoplanet. As the team were waiting for night to fall on the mountain Nic encountered Belinda Nicholson, who is a postdoctoral research assistant working at the University of Oxfords Astrophysics Department, where she studies both exoplanets and stellar astrophysics.
|
|
| 3. |
- Aronson, Erik, et al.
(författare)
-
Model-free inverse method for transit imaging of stellar surfaces : Using transit surveys to map stellar spot coverage
- 2019
-
Ingår i: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 630
-
Tidskriftsartikel (refereegranskat)abstract
- Context: We present a model-free method for mapping surface brightness variations.Aims: We aim to develop a method that is not dependent on either stellar atmosphere models or limb-darkening equation. This method is optimized for exoplanet transit surveys such that a large database of stellar spot coverage can be created.Methods: The method uses light curves from several transit events of the same system. These light curves are phase-folded and median-combined to for a high-quality light curve without temporal local brightness variations. Stellar specific intensities are extracted from this light curve using a model-free method. We search individual light curves for departures from the median-combined light curve. Such departures are interpreted as brightness variations on the stellar surface. A map of brightness variations on the stellar surface is produced by finding the brightness distribution that can produce a synthetic light curve that fits observations well. No assumptions about the size, shape, or contrast of brightness variations are made.Results: We successfully reproduce maps of stellar disks from both synthetic data and archive observations from FORS2, the visual and near UV FOcal Reducer and low dispersion Spectrograph for the Very Large Telescope (VLT).
|
|
| 4. |
- Aronson, Erik, et al.
(författare)
-
Model-independent Exoplanet Transit Spectroscopy
- 2018
-
Ingår i: Astronomical Journal. - : IOP PUBLISHING LTD. - 0004-6256 .- 1538-3881. ; 155:5
-
Tidskriftsartikel (refereegranskat)abstract
- We propose a new data analysis method for obtaining transmission spectra of exoplanet atmospheres and brightness variation across the stellar disk from transit observations. The new method is capable of recovering exoplanet atmosphere absorption spectra and stellar specific intensities without relying on theoretical models of stars and planets. We simultaneously fit both stellar specific intensity and planetary radius directly to transit light curves. This allows stellar models to be removed from the data analysis. Furthermore, we use a data quality weighted filtering technique to achieve an optimal trade-off between spectral resolution and reconstruction fidelity homogenizing the signal-to-noise ratio across the wavelength range. Such an approach is more efficient than conventional data binning onto a low-resolution wavelength grid. We demonstrate that our analysis is capable of reproducing results achieved by using an explicit quadratic limb-darkening equation and that the filtering technique helps eliminate spurious spectral features in regions with strong telluric absorption. The method is applied to the VLT FORS2 observations of the exoplanets GJ 1214 b and WASP-49 b, and our results are in agreement with previous studies. Comparisons between obtained stellar specific intensity and numerical models indicates that the method is capable of accurately reconstructing the specific intensity. The proposed method enables more robust characterization of exoplanetary atmospheres by separating derivation of planetary transmission and stellar specific intensity spectra (that is model-independent) from chemical and physical interpretation.
|
|
| 5. |
- Aronson, Erik, et al.
(författare)
-
Using near-infrared spectroscopy for characterization of transiting exoplanets
- 2015
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 578
-
Tidskriftsartikel (refereegranskat)abstract
- Context. We propose a method for observing transiting exoplanets with near-infrared high-resolution spectrometers. Aims. We aim to create a robust data analysis method for recovering atmospheric transmission spectra from transiting exoplanets over a wide wavelength range in the near-infrared. Methods. By using an inverse method approach, combined with stellar models and telluric transmission spectra, the method recovers the transiting exoplanet's atmospheric transmittance at high precision over a wide wavelength range. We describe our method and have tested it by simulating observations. Results. This method is capable of recovering transmission spectra of high enough accuracy to identify absorption features from molecules such as O-2, CH4, CO2, and H2O. This accuracy is achievable for Jupiter-size exoplanets at S/N that can be reached for 8m class telescopes using high-resolution spectrometers (R > 20 000) during a single transit, and for Earth-size planets and super-Earths transiting late K or M dwarf stars at S/N reachable during observations of less than 10 transits. We also analyse potential error sources to show the robustness of the method. Conclusions. Detection and characterization of atmospheres of both Jupiter-size planets and smaller rocky planets looks promising using this set-up.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Barklem, Paul, et al.
(författare)
-
Hydrogen Line Formation in Cool Stars
- 2001
-
Ingår i: 11th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun. - San Francisco : Astronomical Society of the Pacific. - 1583810552 ; , s. 766-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
