15 research outputs found

    Single-lined Spectroscopic Binary Star Candidates in the RAVE Survey

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    Repeated spectroscopic observations of stars in the RAdial Velocity Experiment (RAVE) database are used to identify and examine single-lined binary (SB1) candidates. The RAVE latest internal database (VDR3) includes radial velocities, atmospheric parameters, and other parameters for approximately a quarter of a million different stars with slightly less than 300,000 observations. In the sample of ~20,000 stars observed more than once, 1333 stars with variable radial velocities were identified. Most of them are believed to be SB1 candidates. The fraction of SB1 candidates among stars with several observations is between 10% and 15% which is the lower limit for binarity among RAVE stars. Due to the distribution of time spans between the re-observation that is biased toward relatively short timescales (days to weeks), the periods of the identified SB1 candidates are most likely in the same range. Because of the RAVE's narrow magnitude range most of the dwarf candidates belong to the thin Galactic disk while the giants are part of the thick disk with distances extending to up to a few kpc. The comparison of the list of SB1 candidates to the VSX catalog of variable stars yielded several pulsating variables among the giant population with radial velocity variations of up to few tens of km s–1. There are 26 matches between the catalog of spectroscopic binary orbits (SB9S_{B^9}) and the whole RAVE sample for which the given periastron time and the time of RAVE observation were close enough to yield a reliable comparison. RAVE measurements of radial velocities of known spectroscopic binaries are consistent with their published radial velocity curves

    The sixth data release of the Radial Velocity Experiment (RAVE) -- II:stellar atmospheric parameters, chemical abundances and distances

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    We present part 2 of the 6th and final Data Release (DR6 or FDR) of the Radial Velocity Experiment (RAVE), a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A) and span the complete time frame from the start of RAVE observations on 12 April 2003 to their completion on 4 April 2013. In the second of two publications, we present the data products derived from 518387 observations of 451783 unique stars using a suite of advanced reduction pipelines focussing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters (Teff, log(g), and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall [alpha/Fe] ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The RAVE DR6 catalogs are cross matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the RAVE Web site (http://rave-survey.org) or the Vizier database.Comment: 65 pages, 33 figures, accepted for publication to A

    The Sixth Data Release of the Radial Velocity Experiment (R ave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances

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    We present part 2 of the sixth and final Data Release (DR6) of the Radial Velocity Experiment (Rave), a magnitude-limited spectroscopic survey of Galactic stars randomly selected in Earth's southern hemisphere. The Rave medium-resolution spectra (R ∌ 7500) cover the Ca triplet region (8410-8795 Å) and span the complete time frame from the start of Rave observations on 2003 April 12 to their completion on 2013 April 4. In the second of two publications, we present the data products derived from 518,387 observations of 451,783 unique stars using a suite of advanced reduction pipelines focusing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters, and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall [α/Fe] ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The Rave DR6 catalogs are cross-matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the Rave website (http://rave-survey.org) or the Vizier database

    Early career researchers’ perspectives and roles in patient-oriented research

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    Plain English summary Patient-oriented research (POR) has received increasing attention in recent years. In this approach, patients’ experiential knowledge, derived from their experiences of living with a condition or illness and of interacting with the healthcare system, is recognized, valued, and seen as complementary to scientific knowledge. Early career researchers (ECRs) are the next generation of researchers, but little is known about how they perceive POR. In this study, ECRs were invited to reflect on what POR is, how patients can best contribute to research, and ECRs’ own role in developing POR. Using a technique designed to collect expert opinions and find consensus—the Delphi method—a panel of 16 ECRs responded, in three rounds, to three questionnaires, with the second and third being built on responses to the preceding ones. Based on their understanding, the panelists agreed that the most important element in defining POR would be valuing, mobilizing, and legitimizing the experiential knowledge of patients who live with a particular health condition. Panelists considered patients to be integral members of the research team, but were less convinced that they should be considered co-researchers. The panelists saw themselves as taking part in developing POR by sharing information, teaching, and encouraging POR among their peers, as well as by participating actively in organizations interested in POR. This is the first study to examine the perspectives of ECRs, who, along with many others, have an important role in supporting the on-going development of POR so that it becomes more widely adopted. Abstract Background Literature on patient-oriented research (POR) is growing rapidly. This field is increasingly encouraged by funders and structured by new research networks. POR involves moving away from considering patients as ‘subjects’, towards perceiving them as experts with experience-based knowledge. However, little is known about how early-career researchers (ECRs) perceive POR and their roles in developing it. This study examined how ECRs perceive POR, patients’ roles, the future of POR, and their own role in developing this approach. Methods A three-round Delphi study was conducted with Quebec’s Strategy for People and Patient-Oriented Research and Trials (SUPPORT) Unit awardees, composed of graduate students and clinicians, all ECRs. Of the 25 invited, 18 agreed to participate (72%), with a three-round retention rate of 89% (n = 16 on 18). Panelists answered open-ended questions, selected the most salient statements, and rated their (dis)agreement with proposals using a 7-point scale. Results Five main themes emerged: 1) ECRs’ knowledge of and experience with POR; 2) the POR definition; 3) patients’ roles and contributions; 4) the future of POR; and 5) ECRs’ roles in POR development. This study revealed that the ECRs were not so familiar with POR, even given their opportunities for networking within a scholarship program. Panelists agreed on the main components of a POR definition: valuing, mobilizing, and legitimizing the experiential knowledge of patients living with a health condition; conducting research that focuses on patients’ concerns, participation, and outcomes; and integrating active partnership among a variety of actors. Panelists considered patients to be integral members of the research team (M = 5.31 ± 1.66), but were less convinced they should be considered co-researchers (M = 4.50 ± 1.75). Panelists saw themselves as playing many roles in developing POR, such as becoming well-informed about it and acting as knowledge brokers, motivators, doers, delegators, and activists. Conclusion The ECRs’ perspectives are informative on how the next generation of researchers envision POR, its future and how they might contribute to developing this approach. There is a clear need for a coherent and concerted strategy for POR capacity development, in which ECRs’ perspectives and their specific needs are taken into account
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