A comprehensive examination of the Eps Eri system -- Verification of a 4 micron narrow-band high-contrast imaging approach for planet searches

Due to its proximity, youth, and solar-like characteristics with a spectral type of K2V, Eps Eri is one of the most extensively studied systems in an extrasolar planet context. Based on radial velocity, astrometry, and studies of the structure of its circumstellar debris disk, at least two planetary companion candidates to Eps Eri have been inferred in the literature (Eps Eri b, Eps Eri c). Some of these methods also hint at additional companions residing in the system. Here we present a new adaptive optics assisted high-contrast imaging approach that takes advantage of the favourable planet spectral energy distribution at 4 microns, using narrow-band angular differential imaging to provide an improved contrast at small and intermediate separations from the star. We use this method to search for planets at orbits intermediate between Eps Eri b (3.4 AU) and Eps Eri c (40 AU). The method is described in detail, and important issues related to the detectability of planets such as the age of Eps Eri and constraints from indirect measurements are discussed. The non-detection of companion candidates provides stringent upper limits for the masses of additional planets. Using a combination of the existing dynamic and imaging data, we exclude the presence of any planetary companion more massive than 3 Mjup anywhere in the Eps Eri system. Specifically, with regards to the possible residual linear radial velocity trend, we find that it is unlikely to correspond to a real physical companion if the system is as young as 200 Myr, whereas if it is as old as 800 Myr, there is an allowed semi-major axis range between about 8.5 and 25 AU.Comment: 11 pages, 8 figures, A&A accepte

GSOC SoE-Editor 2.0 - A Generic Sequence of Events Tool

At the German Space Operations Center (GSOC) two applications had been developed for scheduling operations of Launch and Early Orbit Phases (LEOP), Commissioning Phases or special operations campaigns (e.g. software upload, special orbit maneuvers, etc.): one for low earth orbit (LEO) and one for medium (MEO) and geostationary earth orbit (GEO). The experiences of these tools were now merged with the scheduling capabilities of GSOC's generic mission planning application Pinta (Program for interactive timeline analysis), its scheduling library Plato (Planning tool) and the GSOC web based timeline display TimOnWeb

An apodizing phase plate coronagraph for VLT/NACO

We describe a coronagraphic optic for use with CONICA at the VLT that provides suppression of diffraction from 1.8 to 7 lambda/D at 4.05 microns, an optimal wavelength for direct imaging of cool extrasolar planets. The optic is designed to provide 10 magnitudes of contrast at 0.2 arcseconds, over a D-shaped region in the image plane, without the need for any focal plane occulting mask.Comment: 9 pages, 5 figures, to appear in Proc. SPIE Vol. 773

Status and new operation modes of the versatile VLT/NACO

This paper aims at giving an update on the most versatile adaptive optics fed instrument to date, the well known and successful NACO . Although NACO is only scheduled for about two more years at the Very Large Telescope (VLT), it keeps on evolving with additional operation modes bringing original astronomical results. The high contrast imaging community uses it creatively as a test-bench for SPHERE and other second generation planet imagers. A new visible wavefront sensor (WFS) optimized for Laser Guide Star (LGS) operations has been installed and tested, the cube mode is more and more requested for frame selection on bright sources, a seeing enhancer mode (no tip/tilt correction) is now offered to provide full sky coverage and welcome all kind of extragalactic applications, etc. The Instrument Operations Team (IOT) and Paranal engineers are currently working hard at maintaining the instrument overall performances but also at improving them and offering new capabilities, providing the community with a well tuned and original instrument for the remaining time it is being used. The present contribution delivers a non-exhaustive overview of the new modes and experiments that have been carried out in the past months.Comment: 10 pages, 7 figures, SPIE 2010 Astronomical Instrumentation Proceedin

First Results From VLT NACO Apodizing Phase Plate: 4-micron Images of the Exoplanet beta Pictoris b

Direct imaging of exoplanets requires both high contrast and high spatial resolution. Here, we present the first scientific results obtained with the newly commissioned Apodizing Phase Plate coronagraph (APP) on VLT/NACO. We detected the exoplanet beta Pictoris b in the narrow band filter centered at 4.05 micron (NB4.05). The position angle (209.13 +- 2.12 deg) and the projected separation to its host star (0."354 +- 0".012, i.e., 6.8 +- 0.2 AU at a distance of 19.3 pc) are in good agreement with the recently presented data from Lagrange et al. (2010). Comparing the observed NB4.05 magnitude of 11.20 +- 0.23 mag to theoretical atmospheric models we find a best fit with a 7-10 M_Jupiter object for an age of 12 Myr, again in agreement with previous estimates. Combining our results with published L' photometry we can compare the planet's [L' - NB4.05] color to that of cool field dwarfs of higher surface gravity suggesting an effective temperature of ~1700 K. The best fit theoretical model predicts an effective temperature of ~1470 K, but this difference is not significant given our photometric uncertainties. Our results demonstrate the potential of NACO/APP for future planet searches and provides independent confirmation as well as complementary data for beta Pictoris b.Comment: Accepted for publication by ApJ

Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations

We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast curves from 22 of the stars observed with the VLT NACO adaptive optics system by Masciadri et al. (2005), and 48 of the stars observed with the VLT NACO SDI and MMT SDI devices by Biller et al. (2007) (for a total of 60 unique stars; the median star for our survey is a 30 Myr K2 star at 25 pc), we consider what distributions of planet masses and semi-major axes can be ruled out by these data, based on Monte Carlo simulations of planet populations. We can set this upper limit with 95% confidence: the fraction of stars with planets with semi-major axis from 20 to 100 AU, and mass >4 M_Jup, is 20% or less. Also, with a distribution of planet mass of dN/dM ~ M^-1.16 between 0.5-13 M_Jup, we can rule out a power-law distribution for semi-major axis (dN/da ~ a^alpha) with index 0 and upper cut-off of 18 AU, and index -0.5 with an upper cut-off of 48 AU. For the distribution suggested by Cumming et al. (2007), a power-law of index -0.61, we can place an upper limit of 75 AU on the semi-major axis distribution. At the 68% confidence level, these upper limits state that fewer than 8% of stars have a planet of mass >4 M_Jup between 20 and 100 AU, and a power-law distribution for semi-major axis with index 0, -0.5, and -0.61 cannot have giant planets beyond 12, 23, and 29 AU, respectively. In general, we find that even null results from direct imaging surveys are very powerful in constraining the distributions of giant planets (0.5-13 M_Jup) at large separations, but more work needs to be done to close the gap between planets that can be detected by direct imaging, and those to which the radial velocity method is sensitive.Comment: 46 pages, 17 figures, accepted to Ap

The Arches Cluster - Evidence for a Truncated Mass Function?

We have analyzed high-resolution, adaptive optics (AO) HK observations of the Arches cluster obtained with NAOS/CONICA. With a spatial resolution of 84 mas, the cluster center is uniquely resolved. From these data the present-day mass function (MF) of Arches is derived down to about 4 Msun. The integrated MF as well as the core and 2nd annulus MFs are consistent with a turn-over at 6-7 Msun. This turn-over indicates severe depletion of intermediate and low-mass stars in the Arches cluster, possibly caused by its evolution in the Galactic Center environment. The Arches MF represents the first resolved observation of a starburst cluster exhibiting a low-mass truncated MF. This finding has severe implications for stellar population synthesis modelling of extragalactic starbursts, the derivation of integrated properties such as the total mass of star clusters in dense environments, the survival of low-mass remnants from starburst populations, and chemical enrichment during starburst phases.Comment: aastex preprint, 14 pages, 4 figures, accepted by ApJ Letter

Tagungsprogramm

Erst in den letzten Jahren ist der Bereich wissenschaftlicher Sammlungen stärker in den Fokus gerückt worden. Vor allem die „Empfehlungen zu wissenschaftlichen Sammlungen als Forschungsinfrastrukturen“, die der Wissenschaftsrat im Januar 2011 veröffentlichte, haben einen Schub an Aufmerksamkeit verursacht. Dieser Band der Hamburger Universitätsreden dokumentiert den Rahmen der Jahrestagung der Gesellschaft für Universitätssammlungen 2016 sowie den Vortrag des Direktors des Deutschen Literaturarchivs Marbach, Ulrich Raulff. In seinem Text „Die Dinge und ihre Verwandten“ demonstriert er, wie ein Gegenstand ohne Kontext sogleich seine Bedeutung verliert. Seine eindrücklichen Reflexionen über die Dinge und ihre Sammlung beendet Ulrich Raulff mit einem Appell an die Vertreterinnen und Vertreter der wissenschaftlichen Sammlungen, selbst Forschung zu betreiben, und zwar in den eigenen Beständen. Archive, Museen und Sammlungen dürften nicht darauf warten, dass die Forschung zu ihnen komme, sie sollten sich auch nicht auf die klassische „Forschung in der Erschließung“ beschränken, sondern selbst Forschungsvorhaben initiieren und durchführen, denn nur durch eigenes Verständnis der Forschung lasse sich auch eine sinnvolle Sammlungspolitik entwickeln, die Gegenwart und Zukunft wirklich erreiche. Dem Abdruck des Redetextes folgen 30 Farbaufnahmen besonderer Objekte, die Ulrich Raulff während seines Vortrags im Lichthof der Staats- und Universitätsbibliothek Hamburg präsentiert hat.In the last few years scientific collections has gained significance. In particular, the "Recommendations on Scientific Collections as Research Infrastructures" published by the German Wissenschaftrat (Science Council) in January 2011 have caused a surge in attention. This volume of the series Hamburg\u27s University Speeches (Hamburger Universitätsreden) documents the frame of the Annual Conference of the Society for University Collections (Gesellschafts für Universitätssammlungen) in 2016 and the lecture given by Ulrich Raulff, Director of the German Literary Archives in Marbach. In his text "The Things and their Relatives" he shows how an object without context immediately loses its meaning. Raulff ends his reflections on things and their collection with an appeal to the representatives of the scientific collections to conduct their own research, namely in their own collections. Archives, museums and collections should not wait for being researched. They should not limit themselves to the classical "research in indexing", but should initiate and carry out research projects themselves. Only through their own understanding of research a meaningful collection policy can be developed, which will really reach the present and the future. The text of the speech is followed by 30 colour photographs of special objects presented by Ulrich Raulff during his lecture in the atrium of the Hamburg State and University Library

Gesamtverzeichnis der Hamburger Universitätsreden, Neue Folge

Erst in den letzten Jahren ist der Bereich wissenschaftlicher Sammlungen stärker in den Fokus gerückt worden. Vor allem die „Empfehlungen zu wissenschaftlichen Sammlungen als Forschungsinfrastrukturen“, die der Wissenschaftsrat im Januar 2011 veröffentlichte, haben einen Schub an Aufmerksamkeit verursacht. Dieser Band der Hamburger Universitätsreden dokumentiert den Rahmen der Jahrestagung der Gesellschaft für Universitätssammlungen 2016 sowie den Vortrag des Direktors des Deutschen Literaturarchivs Marbach, Ulrich Raulff. In seinem Text „Die Dinge und ihre Verwandten“ demonstriert er, wie ein Gegenstand ohne Kontext sogleich seine Bedeutung verliert. Seine eindrücklichen Reflexionen über die Dinge und ihre Sammlung beendet Ulrich Raulff mit einem Appell an die Vertreterinnen und Vertreter der wissenschaftlichen Sammlungen, selbst Forschung zu betreiben, und zwar in den eigenen Beständen. Archive, Museen und Sammlungen dürften nicht darauf warten, dass die Forschung zu ihnen komme, sie sollten sich auch nicht auf die klassische „Forschung in der Erschließung“ beschränken, sondern selbst Forschungsvorhaben initiieren und durchführen, denn nur durch eigenes Verständnis der Forschung lasse sich auch eine sinnvolle Sammlungspolitik entwickeln, die Gegenwart und Zukunft wirklich erreiche. Dem Abdruck des Redetextes folgen 30 Farbaufnahmen besonderer Objekte, die Ulrich Raulff während seines Vortrags im Lichthof der Staats- und Universitätsbibliothek Hamburg präsentiert hat.In the last few years scientific collections has gained significance. In particular, the "Recommendations on Scientific Collections as Research Infrastructures" published by the German Wissenschaftrat (Science Council) in January 2011 have caused a surge in attention. This volume of the series Hamburg\u27s University Speeches (Hamburger Universitätsreden) documents the frame of the Annual Conference of the Society for University Collections (Gesellschafts für Universitätssammlungen) in 2016 and the lecture given by Ulrich Raulff, Director of the German Literary Archives in Marbach. In his text "The Things and their Relatives" he shows how an object without context immediately loses its meaning. Raulff ends his reflections on things and their collection with an appeal to the representatives of the scientific collections to conduct their own research, namely in their own collections. Archives, museums and collections should not wait for being researched. They should not limit themselves to the classical "research in indexing", but should initiate and carry out research projects themselves. Only through their own understanding of research a meaningful collection policy can be developed, which will really reach the present and the future. The text of the speech is followed by 30 colour photographs of special objects presented by Ulrich Raulff during his lecture in the atrium of the Hamburg State and University Library