1,721,057 research outputs found
Appendix E. Additional figures
No full textThis are figures E.2 - E.9 from Appendix E of the article entitled "KOBE-1: The first planetary system from the KOBE survey. Two planets likely in the sub-Neptune mass regime around a late K-dwarf" (Balsalobre-Ruza, et al., 2025, A&A). All the complete figures are only shown here.Peer reviewe
Planetary systems across different niches: Synergies between Kepler and Calar Alto observatories
Full text linkTesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 02-07-2015Since the discovery of the first extrasolar planets around two decades ago, more than a thousand
of these worlds have been confirmed and characterized. The wide and unexpected diversity of
properties shown by these planetary systems suggest the complexity of the planet formation and
evolution processes. Apart from providing indications on the formation of the Solar System,
these discoveries have opened many others. Step-by-step, we are providing observational hints
to answer them. In particular, the Kepler mission has provided an impressive sample of planet
candidates of any kind that can be fully characterized thanks to the technique used and the
subsequent ground-based follow-up. This full characterization is important in order to analyze
their origin and evolution history.
In this thesis, we present our contribution to complete the picture of the evolution of planetary
systems. We have performed a comprehensive follow-up of the Kepler candidates by making
use of ground-based instrumentation at Calar Alto Observatory. Due to the characteristics of the
Kepler mission, the detected transits (due to the pass of an object in front of a star) could be due
to other blended configurations mimicking a planetary-like transit. Our work has been centered
on ruling out these configurations, confirming the planetary-nature of the transiting objects,
and analyzing their properties. To that end, we have carried out a two-phases project making
use of different datasets and techniques. The two phases consisted on i) obtaining high-spatial
resolution images of a large sample of Kepler candidates owing to unveil possible companions
and ii) obtaining high-resolution spectroscopy of a smaller carefully selected sub-sample to
monitor the radial velocity of the host star and characterize the physical and orbital properties
of the planet. In addition, we have analyzed the Kepler light curve looking for modulations
induced by the presence of a planetary-mass or substellar object.
The results of this follow-up have yielded to the confirmation of five planets in four host stars.
Among them, we have found the closest-in planet orbiting a giant star (Kepler-91 b), being
the first confirmed planet known to transit one of these evolved stars. Additionally, we confirmed
other close-in giant planet around another giant star (Kepler-432 b), the planet having the
most grazing transit known to date (Kepler-447 b), and a two-planet system revolving around
a young solar-analog (KOI-372). Besides, our high-resolution images of more than 170 planet
host candidates have improved the candidacy of tens of planets and have reported close blended
companions in around 18% of the sample. In this dissertation we present the observations and
analysis that lead to these results and discuss their relevance in the exoplanetary fiel
Appendix F. Additional tables
No full textThis is the Appendix F of the article entitled "KOBE-1: The first planetary system from the KOBE survey. Two planets likely in the sub-Neptune mass regime around a late K-dwarf" (Balsalobre-Ruza, et al., 2025, A&A). Figures from F.3 to F.8 are only available here.Peer reviewe
A systematic bias in template-based RV extraction algorithms
No full textA. M. Silva et al.[Context] The radial velocity (RV) method plays a key role in modern-day astrophysics. One of the most common techniques for extracting precise RVs from state-of-the-art spectrographs is template-matching (TM) algorithms. They have been shown to perform better than a cross-correlation function (CCF) approach in cases of cooler stars (e.g. M dwarfs) and multiple implementations have appeared over the past years. More recently, line-by-line (LBL) approaches offer an alternative avenue to extract RVs by analyzing individual spectral lines.[Aims] In this paper, we identify and explore a previously unidentified, multi-meter-per-second, systematic correlation between time and RVs inferred through TM and LBL methods. We evaluate the influence of the data-driven stellar template in the RV bias and hypothesise on the possible sources of this effect.[Methods] We used the s-BART pipeline to extract RVs from three different datasets gathered over four nights of ESPRESSO and HARPS observations. We demonstrate that the effect can be recovered on a larger sample of 19 targets, totalling 4124 ESPRESSO observations over 38 nights. We also showcase the presence of the bias in RVs extracted with the SERVAL and ARVE pipelines. Lastly, we explore the construction of the stellar template over the five years of ESPRESSO observations of HD 10700, totalling more than 2000 observations.[Results] We find that a systematic quasi-linear bias affects the RV extraction with slopes that vary from —0.3 ms−1 h−1to —52 m s−1 h−1 in our sample. This trend is not observed in CCF RVs and only appears when all observations of a given star are collected within a short time period (timescales of hours). We show that this systematic contamination exists in the RV time series of two different template-matching pipelines and one line-by-line pipeline, and it is agnostic to the spectrograph. We also find that this effect is linked to the construction of the stellar template, as we were able to mitigate it through a careful selection of the observations used to construct it. Our results suggest that a contamination of micro-telluric features, coupled with other sources of correlated noise, could be the driving factor of this effect. We also show that this effect does not impact the usual usage of template-matching for the detection and characterisation of exoplanets. However, the short-timescale science cases, such as asteroseismology as well as transit and atmospheric characterisation, can be severely affected.We thank the helpful comments of Andrew Collier Cameron as the referee of this paper. This work was funded by the European Union (ERC, FIERCE, 101052347). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. This work was also supported by FCT - Fundaçâo para a Ciência e a Tecnologia through national funds by these grants: UIDB/04434/2020 DOI: 10.54499/UIDB/04434/2020, UIDP/04434/2020 DOI: 10.54499/UIDP/04434/2020, PTDC/FIS-AST/4862/2020, UID/04434/2025. TLC is supported by Fundaçâo para a Ciência e a Tecnologia (FCT) in the form of a work contract (2023.08117.CEECIND/CP2839/CT0004). J.H.C.M. acknowledges further support from national funds through the FCT DarkMAGE project (grant ID: PTDC/FIS-AST/4862/2020) and from the project e-CHEOPS (PEA: 4000142255), funded by ESA/PRODEX. JIGH acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) projects PID2020-117493GB-I00 and PID2023-149982NB-I00. ÉA is supported by the Trottier Family Foundation through the Trottier Institute for Research on Exoplanets (IREx). ODSD acknowledges support from e-CHEOPS: PEA No 4000142255. The INAF authors acknowledge financial support of the Italian Ministry of Education, University, and Research with PRIN 201278X4FL and the “Progetti Premiali” funding scheme. X.De acknowledges funding from the French ANR under contract number ANR-24-CE49-3397 (ORVET). This work is supported by the French National Research Agency in the framework of the Investissements d’Avenir program (ANR-15-IDEX-02), through the funding of the “Origin of Life" project of the Grenoble-Alpes University. KA acknowledges support from the Swiss National Science Foundation (SNSF) under the Postdoc Mobility grant P500PT_230225. J.L.-B. is funded by the Spanish Ministry of SCience, Innovation and Universities (MCIN/AEI/10.13039/501100011033) through grants PID2019-107061GB-C61, PID2023-150468NB-I00 and CNS2023-144309. We acknowledge financial support from the Agencia Estatal de Investigaciôn of the Ministerio de Ciencia e Innovaciôn MCIN/AEI/10.13039/501100011033 and the ERDF “A way of making Europe” through project PID2021-125627OB-C32, and from the Centre of Excellence “Severo Ochoa” award to the Instituto de Astrofisica de Canarias. X.Du acknowledges the support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement SCORE No. 851555) and from the Swiss National Science Foundation under the grant SPECTRE (No 200021_215200). This work has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation under grants 51NF40_182901 and 51NF40_205606. FPE would like to acknowledge the Swiss National Science Foundation (SNSF) for supporting research with ESPRESSO through the SNSF grants nr. 140649, 152721, 166227, 184618 and 215190. The ESPRESSO Instrument Project was partially funded through SNSF’s FLARE Programme for large infrastructures. This work was financed by Portuguese funds through FCT (Fundaçâo para a Ciência e a Tecnologia) in the framework of the project 2022.04048.PTDC (Phi in the Sky, DOI 10.54499/2022.04048.PTDC). CJM also acknowledges FCT and POCH/FSE (EC) support through Investigador FCT Contract 2021.01214.CEECIND/CP1658/CT0001 (DOI 10.54499/2021.01214.CEECIND/CP1658/CT0001). ASM acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) projects PID2020-117493GB-I00 and PID2023-149982NB-I00. ARCS acknowledges support from FCT fellowship 2021.07856.BD; This work has received support in the framework of the National Centre of Competence in Research PlanetS supported by the Swiss National Science Foundation under grant 51NF4_205606. The authors acknowledge financial contribution from the European Union - Next Generation EU RRF M4C2 1.1 PRIN MUR 2022 project 2022CERJ49 (ESPLORA).Peer reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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