26 results on '"Peter Buschkamp"'
Search Results
2. CHIME’s hyperspectral imaging spectrometer design result from phase A/B1
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B. Borguet, Markus J. Geiss, S. Pieraccini, Christian Roth, M. Rast, Peter Buschkamp, B. Sang, V. Moreau, L. Maresi, J. Nieke, and P. Peacocke
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Front and back ends ,Spectrometer ,Spacecraft ,Reflecting telescope ,business.industry ,Computer science ,Payload ,Detector ,Hyperspectral imaging ,Satellite ,business ,Remote sensing - Abstract
CHIME, the Copernicus Hyperspectral Imaging Mission for the Environment, is one of the six High Priority Candidate Missions (HPCM) of the evolution in the Copernicus Space Component (CSC) foreseen in the mid-2020s that is proposed for further analysis. In this paper we summarize the results as retrieved by OHB (D) as part of the Phase A/B1. The contract was kicked off in 2018 and concluded in 2020 after finalisation of the Pre-development activities. The proposed instrument is a hyperspectral imager instrument with reflective telescope and grating-based spectrometer. The selected orbit is in the range of 625 ± 30 km, LTDN 10:45 – 11:15 am with a repeat cycle of 20 to 25 days for a single satellite and 10-12.5 days revisit for 2 satellites. The payload of each satellite records at a Spatial Sampling Distance (SSD) of 30m the full spectral range from 400 to 2500nm at a Spectral Sampling interval < 10nm with Low Keystone/Smile. On the front end a high performance TMA with wide-band coated optics collects the light from ground and feeds it to a highly linear almost distortion free spectrometer assembly attaining very good spectral stability. All units are integrated in an optical bench structure that offers excellent AIT access and provides a highly stable LOS. The electro-optical backend contains low-noise cold MCT detectors creating margin in the predicted NEDL performance. The instrument can be calibrated via on-board devices or using reference targets outside the spacecraft. We present the functional decomposition and the physical instrument architecture: the optical design and opto-mechanical layout, the electro-optical imaging chain ant thermal control system.
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- 2021
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3. Design and Optimization of Ultra-Stable Fine-Pointing Structures for the CHIME Instrument
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Bernhard Sang, Markus J. Geiss, Peter Buschkamp, Herbert Loew, and Stephan Rapp
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business.industry ,Computer science ,Optical instrument ,Topology optimization ,Stiffness ,Mechanical engineering ,Hyperspectral imaging ,Decoupling (cosmology) ,Modular design ,Breadboard ,law.invention ,law ,medicine ,medicine.symptom ,business ,Focus (optics) - Abstract
CHIME (Copernicus Hyperspectral Imaging Mission for the Environment) is part of ESA’s Sentinel Expansion Program for which OHB System AG in Oberpfaffenhofen, Germany has been selected as the instrument prime contractor. In this paper we present the development of the ultra-stable stiffness architecture for the instrument structure. Backed by a trade study of different structural concepts with a focus on the opto-mechanical decoupling, assembly integration and test accessibility, and the demanding optical performance criteria, we derive a robust solution: The main stiffness element is a central monolithic CFRP (Carbon Fiber Reinforced Plastic) torus, on which several sub-elements are mounted for precise positioning of the highly-sensitive optical elements, creating a modular 3D optical bench. We demonstrate the use of topology optimization for design concept finding considering mass and performance criteria. The paper concludes with the results from a breadboard test campaign and an outlook on the next development steps.
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- 2021
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4. Design study of a hosted Arctic imager for weather and climate monitoring in the polar regions
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Paolo Sandri, Peter Buschkamp, Frank te Hennepe, Stephan Gulde, Patrick Tully Peacocke, and Charlotte Bewick
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Telescope ,Elliptic orbit ,Arctic ,law ,Aperture ,Multispectral image ,Ground sample distance ,Environmental science ,Weather and climate ,Spectral bands ,Remote sensing ,law.invention - Abstract
A Hosted Arctic Imager (HAI) concept is currently being investigated as part of ESA’s Polaris program. HAI intends to fulfil the needs for providing weather and atmospheric services in the polar regions enabling e.g. near-real-time observations of Atmospheric Motion Vectors of the Arctic and Nordic regions, similar to the measurements offered by its Meteosat counterparts in GEO, such as SEVIRI on MSG and FCI on MTG. The compact hosted-payload multispectral imager operates from a High Elliptical Orbit in 12 spectral bands from 0.4μm to 13.3μm at a Ground Sampling Distance of 1-3km. The optical concepts employs a split design into a wavelength-optimized VIS and a (N)IR telescope, built as all-metal free-form optics, where a hole in the first mirror of the (N)IR telescope presents the entrance aperture of the VIS telescope. Our instrument design maximizes the re-use of heritage technology, e.g. for detectors, scanner, and calibration elements, in order to enable a low-risk fast-track development program.
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- 2019
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5. Final design of optical fibre routing for 4MOST
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Swara Rahurkar, Allar Saviauk, Dennis Plüschke, Roger Haynes, Jean-Emmanuel Migniau, Patrick Caillier, Walter Seifert, C. Feiz, Tomas Jahn, Dionne M. Haynes, Johannes Piotrowski, Peter Buschkamp, and Andreas Kelz
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Optical fiber ,Computer science ,business.industry ,Cassegrain reflector ,law.invention ,Azimuth ,Telescope ,Cardinal point ,law ,Observatory ,Mechanical design ,Aerospace engineering ,Routing (electronic design automation) ,business - Abstract
4MOST is a fibre-fed, multi-object spectroscopic survey facility to be installed on the VISTA telescope at ESO's Paranal observatory. This paper presents the final mechanical design of the optical fibre route from the fibre positioner at the focal plane of VISTA to the fibre-slits within the high- and low-resolution spectrographs below the azimuth platform. The technical challenges are to provide a safe, durable and efficient fibre route for over 2400 fibres. To accommodate the movements of the telescope, a Cassegrain Cable Wrap and a novel elevation chain concept has been prototyped and extensively tested to validate the design solutions.
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- 2018
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6. ARGOS at the LBT. Binocular laser guided ground layer adaptive optics
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J. Borelli, Jamison Noenickx, L. Barl, Hans Gemperlein, Matthias Rosensteiner, Udo Beckmann, Y. Qin, A. Sivitilli, R. Angel, M. Rademacher, Ric Davies, C. Kohlmann, J. Ziegleder, R. Genzel, A. Contursi, D. Peter, Alfio Puglisi, M. Elberich, Jesper Storm, Matthias Steinmetz, C. Veillet, Peter Buschkamp, Lorenzo Busoni, Piero Salinari, W. Raab, G. Orban de Xivry, H. W. Rix, Martin Kulas, T. Ott, A. Cardwell, C. Connot, Frank Eisenhauer, Andreas Quirrenbach, Richard F. Green, Marco Bonaglia, Olivier Durney, Brenda Frye, Sirio Belli, Joar Brynnel, Victor Gasho, Christian Schwab, Sebastian Rabien, M. Deysenroth, Michael Lefebvre, Gerd Weigelt, Simone Esposito, Gustavo Rahmer, Tommaso Mazzoni, Iskren Y. Georgiev, Wolfgang Gaessler, Michael Hart, ITA, USA, and DEU
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Point spread function ,FOS: Physical sciences ,Field of view ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Optics ,0103 physical sciences ,Spectral resolution ,Adaptive optics ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Astrophysics::Galaxy Astrophysics ,Physics ,Wavefront ,010308 nuclear & particles physics ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy and Astrophysics ,Large Binocular Telescope ,Astrophysics - Astrophysics of Galaxies ,Gravitational lens ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Magnitude (astronomy) ,business ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Having completed its commissioning phase, the Advanced Rayleigh guided Ground-layer adaptive Optics System (ARGOS) facility is coming online for scientific observations at the Large Binocular Telescope (LBT). With six Rayleigh laser guide stars in two constellations and the corresponding wavefront sensing, ARGOS corrects the ground-layer distortions for both LBT 8.4m eyes with their adaptive secondary mirrors. Under regular observing conditions, this set-up delivers a point spread function (PSF) size reduction by a factor of ~2--3 compared to a seeing-limited operation. With the two LUCI infrared imaging and multi-object spectroscopy instruments receiving the corrected images, observations in the near-infrared can be performed at high spatial and spectral resolution. We discuss the final ARGOS technical set-up and the adaptive optics performance. We show that imaging cases with ground-layer adaptive optics (GLAO) are enhancing several scientific programmes, from cluster colour magnitude diagrams and Milky Way embedded star formation, to nuclei of nearby galaxies or extragalactic lensing fields. In the unique combination of ARGOS with the multi-object near-infrared spectroscopy available in LUCI over a 4x4 arcmin field of view, the first scientific observations have been performed on local and high-z objects. Those high spatial and spectral resolution observations demonstrate the capabilities now at hand with ARGOS at the LBT., 21 pages, 28 figures
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- 2018
7. LBT/ARGOS adaptive optics observations of z$\sim 2$ lensed galaxies
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Mirko Curti, Sirio Belli, Gustavo Rahmer, Iskren Y. Georgiev, Giovanni Cresci, Tommaso Mazzoni, Wolfgang Gaessler, L. Busoni, Martin Kulas, J. Ziegleder, M. Bonaglia, D. Peter, J. Borelli, Simone Esposito, M. Deysenroth, Michele Perna, Sebastian Rabien, Walfried Raab, G. Orban de Xivry, Dieter Lutz, Claudio Grillo, Hans Gemperlein, Matthias Rosensteiner, A. Contursi, F. Mannucci, Peter Buschkamp, Stefano Zibetti, ITA, and DEU
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Physics ,010308 nuclear & particles physics ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Adaptive optics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Gravitationally lensed systems allow a detailed view of galaxies at high redshift. High spatial- and spectral-resolution measurements of arc-like structures can offer unique constraints on the physical and dynamical properties of high-z systems. We present near-infrared spectra centred on the gravitational arcs of six known z ~ 2 lensed star-forming galaxies of stellar masses of 10^9-10^11 Msun and star formation rate (SFR) in the range between 10 and 400 Msun/yr. Ground layer adaptive optics (AO)-assisted observations are obtained at the Large Binocular Telescope (LBT) with the LUCI spectrographs during the commissioning of the ARGOS facility. We used MOS masks with curved slits to follow the extended arched structures and study the diagnostic emission lines. Combining spatially resolved kinematic properties across the arc-like morphologies, emission line diagnostics and archival information, we distinguish between merging and rotationally supported systems, and reveal the possible presence of ejected gas. For galaxies that have evidence for outflows, we derive outflow energetics and mass-loading factors compatible with those observed for stellar winds in local and high-z galaxies. We also use flux ratio diagnostics to derive gas-phase metallicities. The low signal-to-noise ratio in the faint H$\beta$ and nitrogen lines allows us to derive an upper limit of ~ 0.15 dex for the spatial variations in metallicity along the slit for the lensed galaxy J1038. Analysed near-infrared spectra presented here represent the first scientific demonstration of performing AO-assisted multi-object spectroscopy with narrow curved-shape slits. The increased angular and spectral resolution, combined with the binocular operation mode with the 8.4-m-wide eyes of LBT, will allow the characterisation of kinematic and chemical properties of a large sample of galaxies at high-z in the near future., Comment: 18 pages, 13 figures, accepted for publication in A&A
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- 2018
8. Resolving the host galaxy of a distant blazar with LBT/LUCI 1 + ARGOS
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Gustavo Rahmer, Iskren Y. Georgiev, G. Orban de Xivry, Tommaso Mazzoni, Martin Kulas, Matthias Rosensteiner, D. Peter, Wolfgang Gässler, Roberto Decarli, Emanuele Paolo Farina, Sebastian Rabien, M. Bonaglia, L. Busoni, Tomislav Terzić, J. Borelli, Peter Buschkamp, and J. Ziegleder
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,010504 meteorology & atmospheric sciences ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,0103 physical sciences ,Blazar ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,Luminous infrared galaxy ,Cosmic distance ladder ,Astronomy and Astrophysics ,Large Binocular Telescope ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Extragalactic background light ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Magnitude (astronomy) ,instrumentation: adaptive optics, infrared: galaxies, BL Lacertae objects: individual: HESS J1943+213 ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
BL Lac objects emitting in the Very High Energy (VHE) regime are unique tools to peer into the properties of the Extragalactic Background Light (EBL). However, due to the typical absence of features in their spectra, the determination of their redshifts has proven challenging. In this work we exploit the superb spatial resolution delivered by the new Advanced Rayleigh guided Ground layer adaptive Optics System (ARGOS) at the Large Binocular Telescope to detect the host galaxy of HESS J1943+213, a VHE emitting BL Lac shining through the Galaxy. Deep H-band imaging collected during the ARGOS commissioning allowed us to separate the contribution of the nuclear emission and to unveil the properties of the host galaxy with unprecedented detail. The host galaxy is well fitted by a S\'ersic profile with index of n~2 and total magnitude of H~16.15 mag. Under the assumption that BL Lac host galaxies are standard candles, we infer a redshift of z~0.21. In the framework of the current model for the EBL, this value is in agreement with the observed dimming of the VHE spectrum due to the scatter of energetic photons on the EBL., Comment: 6 pages, 4 figures, 1 table. If you would like to have access to the fully reduced H-band image of HESS J1943+213 please inquire the first Author or check https://github.com/EmAstro/LBT_ARGOS/. Accepted for publication in MNRAS
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- 2018
9. 4MOST: the high-resolution spectrograph
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Allar Saviauk, Walter Seifert, W. Xu, Holger Mandel, A. Quirrenbach, C. Feiz, Peter Buschkamp, and Samuel C. Barden
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media_common.quotation_subject ,High resolution ,Field of view ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,law.invention ,010309 optics ,Telescope ,Optics ,law ,0103 physical sciences ,Mechanical design ,Astrophysics::Solar and Stellar Astrophysics ,Spectral resolution ,Spectroscopy ,010303 astronomy & astrophysics ,Spectrograph ,Astrophysics::Galaxy Astrophysics ,media_common ,Remote sensing ,Physics ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Sky ,Astrophysics::Earth and Planetary Astrophysics ,business - Abstract
4MOST (4-meter Multi-Object Spectroscopic Telescope) is a wide-field, fiber-feed, high-multiplex spectroscopic survey facility to be installed on the 4-meter ESO telescope VISTA in Chile. It consists of two identical low resolution spectrographs and one high resolution spectrograph. The instrument is presently in the preliminary design phase and expected to get operational end of 2022. The high resolution spectrograph will afford simultaneous observations of up to 812 targets - over a hexagonal field of view of ~ 4.1 sq.degrees on sky - with a spectral resolution R>18,000 covering a wavelength range from 393 to 679nm in three channels. In this paper we present the optical and mechanical design of the high resolution spectrograph (HRS) as prepared for the review at ESO, Garching. The expected performance including the highly multiplexed fiber slit concept is simulated and its impact on the optical performance given. We show the thermal and finite element analyses and the resulting stability of the spectrograph under operational conditions.
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- 2016
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10. HIGH-REDSHIFT STAR-FORMING GALAXIES: ANGULAR MOMENTUM AND BARYON FRACTION, TURBULENT PRESSURE EFFECTS, AND THE ORIGIN OF TURBULENCE
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Amiel Sternberg, K. Shapiro, R. D. Davies, Peter Buschkamp, E. K. S. Hicks, Andreas Burkert, N. Foerster-Schreiber, Reinhard Genzel, Dieter Lutz, Sadegh Khochfar, Jesper Sommer-Larsen, Giovanni Cresci, Nicolas Bouché, Linda J. Tacconi, Shy Genel, and T. Naab
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Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Cold dark matter ,Star formation ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Redshift ,Galaxy ,Gravitation ,Baryon ,Dark matter halo ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Energy source ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The structure of a sample of high-redshift (z=2), rotating galaxies with high star formation rates and turbulent gas velocities of sigma=40-80 km/s is investigated. Fitting the observed disk rotational velocities and radii with a Mo, Mao, White (1998) (MMW) model requires unusually large disk spin parameters lambda_d>0.1 and disk-to-dark halo mass fraction m_d=0.2, close to the cosmic baryon fraction. The galaxies segregate into dispersion-dominated systems with 1200 km/s, vmax/sigma>3 and rd=4-8 kpc. For the dispersion-dominated sample, radial pressure gradients partly compensate the gravitational force, reducing the rotational velocities. Including this pressure effect in the MMW model, dispersion-dominated galaxies can be fitted well with spin parameters lf lambda_d=0.03-0.05 for high disk mass fractions of m_d=0.2 and with lambda_d=0.01-0.03 for m_d=0.05. These values are in good agreement with cosmological expectations. For the rotation-dominated sample however pressure effects are small and better agreement with theoretically expected disk spin parameters can only be achieved if the dark halo mass contribution in the visible disk regime (2-3*rd) is smaller than predicted by the MMW model. We argue that these galaxies can still be embedded in standard cold dark matter halos if the halos did not contract adiabatically in response to disk formation. It is shown that the observed high turbulent gas motions of the galaxies are consistent with a Toomre instability parameter Q=1 which is equal to the critical value, expected for gravitational disk instability to be the major driver of turbulence. The dominant energy source of turbulence is then the potential energy of the gas in the disk., Comment: 23 pages, 4 figures, ApJ, in press
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- 2010
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11. The Blue Straggler Population in the Globular Cluster M53 (NGC 5024): A CombinedHST, LBT, and CFHT Study1
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C. De Santis, A. Di Paola, R. T. Rood, E. Diolaiti, Roberto Speziali, J. Farinato, F. Gasparo, F. Fusi Pecci, Nicolas Bouché, A. Grazian, Peter Buschkamp, Barbara Lanzoni, Fernando Pedichini, G. Gentile, Riccardo Smareglia, Vincenzo Testa, Fabio Pasian, M. Bellazzini, F. R. Ferraro, E. Giallongo, L. Pulone, Stefano Gallozzi, Andrea Baruffolo, Adriano Fontana, E. Vernet, Giacomo Beccari, and Roberto Ragazzoni
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Physics ,education.field_of_study ,Population ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Star count ,Radius ,Blue straggler ,Stars ,Space and Planetary Science ,Globular cluster ,Cluster (physics) ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Tidal tail ,education ,Astrophysics::Galaxy Astrophysics - Abstract
We used a proper combination of multiband high-resolution and wide field multi-wavelength observations collected at three different telescopes (HST, LBT and CFHT) to probe Blue Straggler Star (BSS) populations in the globular cluster M53. Almost 200 BSS have been identified over the entire cluster extension. The radial distribution of these stars has been found to be bimodal (similarly to that of several other clusters) with a prominent dip at ~60'' (~2 r_c) from the cluster center. This value turns out to be a factor of two smaller than the radius of avoidance (r_avoid, the radius within which all the stars of ~1.2 M_sun have sunk to the core because of dynamical friction effects in an Hubble time). While in most of the clusters with a bimodal BSS radial distribution, r_avoid has been found to be located in the region of the observed minimum, this is the second case (after NGC6388) where this discrepancy is noted. This evidence suggests that in a few clusters the dynamical friction seems to be somehow less efficient than expected. We have also used this data base to construct the radial star density profile of the cluster: this is the most extended and accurate radial profile ever published for this cluster, including detailed star counts in the very inner region. The star density profile is reproduced by a standard King Model with an extended core (~25'') and a modest value of the concentration parameter (c=1.58). A deviation from the model is noted in the most external region of the cluster (at r>6.5' from the center). This feature needs to be further investigated in order to address the possible presence of a tidal tail in this cluster.
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- 2008
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12. Evidence for Wide-spread Active Galactic Nucleus-driven Outflows in the Most Massive z 1-2 Star-forming Galaxies
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Philipp Lang, Frank Eisenhauer, C. M. Carollo, Alvio Renzini, E. Wuyts, Stijn Wuyts, Jeffrey C. C. Chan, Linda J. Tacconi, Mariska Kriek, Erica J. Nelson, Peter Buschkamp, Amiel Sternberg, R. P. Saglia, G. B. Brammer, Matteo Fossati, Richard Davies, Alessandra Beifiori, Jaron Kurk, P. G. van Dokkum, David J. Wilman, David J. Rosario, Andreas Burkert, Dieter Lutz, Sandro Tacchella, K. Bandara, Ivelina Momcheva, S. Berta, Reinhard Genzel, Simon J. Lilly, T. Naab, Chiara Mancini, M. H. Fabricius, N. M. Förster Schreiber, Ray M. Sharples, Ralf Bender, Emily Wisnioski, Sandesh K. Kulkarni, J. T. Mendel, Genzel, R, Forster Schreiber, N, Rosario, D, Lang, P, Lutz, D, Wisnioski, E, Wuyts, E, Wuyts, S, Bandara, K, Bender, R, Berta, S, Kurk, J, Mendel, J, Tacconi, L, Wilman, D, Beifiori, A, Brammer, G, Burkert, A, Buschkamp, P, Chan, J, Carollo, C, Davies, R, Eisenhauer, F, Fabricius, M, Fossati, M, Kriek, M, Kulkarni, S, Lilly, S, Mancini, C, Momcheva, I, Naab, T, Nelson, E, Renzini, A, Saglia, R, Sharples, R, Sternberg, A, Tacchella, S, and Van Dokkum, P
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Physics ,Luminous infrared galaxy ,Active galactic nucleus ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,galaxies [infrared] ,Galaxy ,infrared: galaxies ,Stars ,galaxies. [Infrared] ,Space and Planetary Science ,galaxies: high-redshift ,kinematics and dynamics [galaxies] ,Galaxy formation and evolution ,galaxies: kinematics and dynamic ,galaxies: evolution ,Stellar evolution ,Astrophysics::Galaxy Astrophysics ,evolution [galaxies] ,high-redshift [galaxies] ,Line (formation) - Abstract
In this paper, we follow up on our previous detection of nuclear ionized outflows in the most massive (log(M */M ☉) ≥ 10.9) z ~ 1-3 star-forming galaxies by increasing the sample size by a factor of six (to 44 galaxies above log(M */M ☉) ≥ 10.9) from a combination of the SINS/zC-SINF, LUCI, GNIRS, and KMOS3Dspectroscopic surveys. We find a fairly sharp onset of the incidence of broad nuclear emission (FWHM in the Hα, [N II], and [S II] lines ~450-5300 km s–1), with large [N II]/Hα ratios, above log(M */M ☉) ~ 10.9, with about two-thirds of the galaxies in this mass range exhibiting this component. Broad nuclear components near and above the Schechter mass are similarly prevalent above and below the main sequence of star-forming galaxies, and at z ~ 1 and ~2. The line ratios of the nuclear component are fit by excitation from active galactic nuclei (AGNs), or by a combination of shocks and photoionization. The incidence of the most massive galaxies with broad nuclear components is at least as large as that of AGNs identified by X-ray, optical, infrared, or radio indicators. The mass loading of the nuclear outflows is near unity. Our findings provide compelling evidence for powerful, high-duty cycle, AGN-driven outflows near the Schechter mass, and acting across the peak of cosmic galaxy formation.
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- 2014
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13. Status of the ARGOS project
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Joar Brynnel, M. Deysenroth, Martin Kulas, Hans Gemperlein, E. Nussbaum, Marco Bonaglia, Michael Lefebvre, Lorenzo Busoni, Andreas Quirrenbach, L. Barl, Sebastian Rabien, Walfried Raab, Gilles Orban de Xivry, Udo Beckmann, Gustavo Rahmer, Simone Esposito, C. Connot, J. Borelli, Wolfgang Gässler, D. Peter, Peter Buschkamp, Julian C. Christou, Tommaso Mazzoni, Richard Davies, Jesper Storm, M. Lehmitz, J. Ziegleder, and Michael Hart
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Wavefront ,Physics ,business.industry ,media_common.quotation_subject ,Large Binocular Telescope ,Laser ,Encircled energy ,law.invention ,Telescope ,Laser guide star ,Optics ,Sky ,law ,Adaptive optics ,business ,media_common ,Remote sensing - Abstract
ARGOS is the Laser Guide Star and Wavefront sensing facility for the Large Binocular Telescope. With first laser light on sky in 2013, the system is currently undergoing commissioning at the telescope. We present the overall status and design, as well as first results on sky. Aiming for a wide field ground layer correction, ARGOS is designed as a multi- Rayleigh beacon adaptive optics system. A total of six powerful pulsed lasers are creating the laser guide stars in constellations above each of the LBTs primary mirrors. With a range gated detection in the wavefront sensors, and the adaptive correction by the deformable secondary’s, we expect ARGOS to enhance the image quality over a large range of seeing conditions. With the two wide field imaging and spectroscopic instruments LUCI1 and LUCI2 as receivers, a wide range of scientific programs will benefit from ARGOS. With an increased resolution, higher encircled energy, both imaging and MOS spectroscopy will be boosted in signal to noise by a large amount. Apart from the wide field correction ARGOS delivers in its ground layer mode, we already foresee the implementation of a hybrid Sodium with Rayleigh beacon combination for a diffraction limited AO performance.
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- 2014
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14. Nebular Excitation in z 2 Star-forming Galaxies from the SINS and LUCI Surveys: The Influence of Shocks and Active Galactic Nuclei
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R. D. Davies, Alvio Renzini, N. M. Förster Schreiber, Reinhard Genzel, A. Burkert, T. Naab, Frank Eisenhauer, Amiel Sternberg, Dieter Lutz, Linda J. Tacconi, Ben Weiner, Y. Peng, Shy Genel, Orly Gnat, S. J. Lilly, K. Shapiro Griffin, G. Zamorani, J. D. Kurk, Peter Buschkamp, E. K. S. Hicks, Chiara Mancini, D. Vergani, Giovanni Cresci, David J. Rosario, Stijn Wuyts, C. M. Carollo, and S. Newman
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Physics ,Active galactic nucleus ,Stellar mass ,Astrophysics::High Energy Astrophysical Phenomena ,Metallicity ,Astronomy and Astrophysics ,Astrophysics ,Photoionization ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxy ,Redshift ,Space and Planetary Science ,Ionization ,Emission spectrum ,Astrophysics::Galaxy Astrophysics - Abstract
Based on high-resolution, spatially resolved data of 10 z ~ 2 star-forming galaxies from the SINS/zC-SINF survey and LUCI data for 12 additional galaxies, we probe the excitation properties of high-z galaxies and the impact of active galactic nuclei (AGNs), shocks, and photoionization. We explore how these spatially resolved line ratios can inform our interpretation of integrated emission line ratios obtained at high redshift. Many of our galaxies fall in the "composite" region of the z ~ 0 [N II]/Hα versus [O III]/Hβ diagnostic (BPT) diagram, between star-forming galaxies and those with AGNs. Based on our resolved measurements, we find that some of these galaxies likely host an AGN, while others appear to be affected by the presence of shocks possibly caused by an outflow or from an enhanced ionization parameter as compared with H II regions in normal, local star-forming galaxies. We find that the Mass-Excitation (MEx) diagnostic, which separates purely star-forming and AGN hosting local galaxies in the [O III]/Hβ versus stellar mass plane, does not properly separate z ~ 2 galaxies classified according to the BPT diagram. However, if we shift the galaxies based on the offset between the local and z ~ 2 mass-metallicity relation (i.e., to the mass they would have at z ~ 0 with the same metallicity), we find better agreement between the MEx and BPT diagnostics. Finally, we find that metallicity calibrations based on [N II]/Hα are more biased by shocks and AGNs at high-z than the [O III]/Hβ/[N II]/Hα calibration.
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- 2014
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15. LUCI in the sky: performance and lessons learned in the first two years of near-infrared multi-object spectroscopy at the LBT
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Walter Seifert, R. Lederer, Sebastian Rabien, M. Honsberg, Hans Gemperlein, Nancy Ageorges, Reiner Hofmann, Jaron Kurk, Frank Eisenhauer, Peter Buschkamp, Vianak Naranjo, Kai Lars Polsterer, Reinhard Genzel, and M. Lehmitz
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Physics ,Upgrade ,Optics ,Sky ,business.industry ,media_common.quotation_subject ,Near-infrared spectroscopy ,Detector ,Spectroscopy ,business ,Spectrograph ,media_common ,Remote sensing - Abstract
LUCI (former LUCIFER) is the full cryogenic near-infrared multi-object spectrograph and imager at the LBT. It presently allows for seeing limited imaging and multi-object spectroscopy at R~2000-4000 in a 4x4arcmin 2 FOV from 0.9 to 2.5 micron. We report on the instrument performance and the lessons learned during the first two years on sky from a technical and operational point of view. We present the upcoming detector upgrade to Hawaii-2 RG arrays and the operating modes to utilize the binocular mode, the LBT facility AO system for diffraction limited imaging as well as to use the wide-field AO correction afforded by the multi-laser GLAO System ARGOS in multi-object spectroscopy.
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- 2012
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16. Status of the ARGOS ground layer adaptive optics system
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Matt Rademacher, Sebastian Ihle, Andreas Quirrenbach, Richard F. Green, Peter Buschkamp, Walfried Raab, Joar Brynnel, E. Nussbaum, Lorenzo Busoni, Udo Beckmann, Michael Lloyd-Hart, P. Hubbard, J. Borelli, Richard Davies, Luca Carbonaro, Victor Gasho, L. Barl, C. Connot, Christina Loose, Jamison Noenickx, Jesper Storm, Christian Schwab, D. Peter, M. Lehmitz, Martin Kulas, Marcus Haug, Marco Bonaglia, J. Ziegleder, Olivier Durney, Jason Lewis, Vidhya Vaitheeswaran, Thomas Bluemchen, Gilles Orban de Xivry, Guido Brusa, M. Deysenroth, Hans Gemperlein, Sebastian Rabien, Simone Esposito, Wolfgang Gässler, and R. Lederer
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Physics ,business.industry ,Large Binocular Telescope ,Wavefront sensor ,law.invention ,Telescope ,Primary mirror ,Laser guide star ,Optics ,law ,Adaptive optics ,business ,Secondary mirror ,Spectrograph ,Computer hardware - Abstract
ARGOS the Advanced Rayleigh guided Ground layer adaptive Optics System for the LBT (Large Binocular Telescope) is built by a German-Italian-American consortium. It will be a seeing reducer correcting the turbulence in the lower atmosphere over a field of 2' radius. In such way we expect to improve the spatial resolution over the seeing of about a factor of two and more and to increase the throughput for spectroscopy accordingly. In its initial implementation, ARGOS will feed the two near-infrared spectrograph and imager - LUCI I and LUCI II. The system consist of six Rayleigh lasers - three per eye of the LBT. The lasers are launched from the back of the adaptive secondary mirror of the LBT. ARGOS has one wavefront sensor unit per primary mirror of the LBT, each of the units with three Shack-Hartmann sensors, which are imaged on one detector. In 2010 and 2011, we already mounted parts of the instrument at the telescope to provide an environment for the main sub-systems. The commissioning of the instrument will start in 2012 in a staged approach. We will give an overview of ARGOS and its goals and report about the status and new challenges we encountered during the building phase. Finally we will give an outlook of the upcoming work, how we will operate it and further possibilities the system enables by design.
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- 2012
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17. Black Hole Mass Estimates Based on C IV are Consistent With Those Based on the Balmer Lines
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Vianak Naranjo, S. Mathur, Rainer Lenzen, R. Lederer, Ulrich Mall, Dong Zhang, J. van Saders, Hans Gemperlein, Christopher S. Kochanek, Anna Pasquali, M. Dietrich, Roberto J. Assef, Walter Seifert, Bradley M. Peterson, Mukremin Kilic, C. Feiz, Reiner Hofmann, M. Lehmitz, Peter Buschkamp, Clemens Storz, Werner Laun, P. Mueller, Marcus Juette, Holger Mandel, Rubab Khan, Catherine J. Grier, E. E. Falco, R. W. Pogge, K. K. Madsen, P. Weiser, A. Quirrenbach, K. Mogren, B. J. Shappee, S. Kozłowski, Kelly D. Denney, A. Germeroth, D. Stern, Volker Knierim, Kai Lars Polsterer, Nancy Ageorges, Paul Martini, and R. S. Barrows
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Physics ,Supermassive black hole ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Balmer series ,Sigma ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,medicine.disease_cause ,Spectral line ,symbols.namesake ,Full width at half maximum ,Space and Planetary Science ,medicine ,symbols ,Astrophysics::Solar and Stellar Astrophysics ,Emission spectrum ,Ultraviolet ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on the CIV, Halpha and Hbeta broad emission lines. Our sample is based upon that of Greene, Peng & Ludwig, expanded with new near-IR spectroscopic observations, consistently analyzed high S/N optical spectra, and consistent continuum luminosity estimates at 5100A. We find that BH mass estimates based on the FWHM of CIV show a systematic offset with respect to those obtained from the line dispersion, sigma_l, of the same emission line, but not with those obtained from the FWHM of Halpha and Hbeta. The magnitude of the offset depends on the treatment of the HeII and FeII emission blended with CIV, but there is little scatter for any fixed measurement prescription. While we otherwise find no systematic offsets between CIV and Balmer line mass estimates, we do find that the residuals between them are strongly correlated with the ratio of the UV and optical continuum luminosities. Removing this dependency reduces the scatter between the UV- and optical-based BH mass estimates by a factor of approximately 2, from roughly 0.35 to 0.18 dex. The dispersion is smallest when comparing the CIV sigma_l mass estimate, after removing the offset from the FWHM estimates, and either Balmer line mass estimate. The correlation with the continuum slope is likely due to a combination of reddening, host contamination and object-dependent SED shapes. When we add additional heterogeneous measurements from the literature, the results are unchanged., Accepted for publication in The Astrophysical Journal. 37 text pages + 8 tables + 23 figures. Updated with comments by the referee and with a expanded discussion on literature data including new observations
- Published
- 2011
18. LUCIFER1 commissioning at the LBT
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L. Schäffner, Peter Buschkamp, Werner Laun, Peter Müller, Marcus Jütte, Clemens Storz, Hans Gemperlein, C. Feiz, Anna Pasquali, John M. Hill, Walter Seifert, M. Lehmitz, Holger Mandel, A. Quirrenbach, Ulrich Mall, Kai Lars Polsterer, A. Germeroth, P. Weiser, Nancy Ageorges, Volker Knierim, Rainer Lenzen, R. Lederer, Vianak Naranjo, and Reiner Hofmann
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Physics ,Pixel ,biology ,business.industry ,Near-infrared spectroscopy ,Large Binocular Telescope ,biology.organism_classification ,law.invention ,Telescope ,Narrow band ,Optics ,law ,business ,Lucifer - Abstract
LUCIFER 1 is the rst of two identical camera-spectrograph units installed at the LBT (Large Binocular Telescope) on Mount Graham in Arizona. Its commissioning took place between September 2008 and November 2009 and has immediately been followed by science operations since December 2009. LUCIFER has a 4x4 arcminute eld of view. It is equipped with a 2048x2048 pixel HAWAII-2 array, suitable lters (broad-band z, J, H, K & Ks plus 12 medium and narrow band near-infrared lters) and three gratings for spectroscopy for a resolution of up to 15000. LUCIFER has 3 cameras: two specic for seeing limited imaging (the N3.75 camera, with 0.12"/pixel) and spectroscopy (the N1.8 camera, with 0.25"/pixel) and one for diraction limited observations (the N30 camera). We report here about the completed seeing-limited commissioning, thus using only two of the cameras.
- Published
- 2010
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19. The LUCIFER MOS: a full cryogenic mask handling unit for a near-infrared multi-object spectrograph
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M. Honsberg, Marcus Haug, Nancy Ageorges, Frank Eisenhauer, Kai Lars Polsterer, Reinhard Genzel, Walter Seifert, Hans Gemperlein, Peter Buschkamp, Reiner Hofmann, Johann Eibl, and R. Lederer
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Physics ,Cryostat ,business.industry ,System of measurement ,Near-infrared spectroscopy ,Large Binocular Telescope ,law.invention ,Telescope ,Cardinal point ,Optics ,law ,Thermal ,business ,Spectrograph - Abstract
The LUCIFER-MOS unit is the full cryogenic mask-exchange unit for the near-infrared multi-object spectrograph LUCIFER at the Large Binocular Telescope. We present the design and functionality of this unique device. In LUCIFER the masks are stored, handled, and placed in the focal plane under cryogenic conditions at all times, resulting in very low thermal background emission from the masks during observations. All mask manipulations are done by a novel cryogenic mask handling robot that can individually address up to 33 fixed and user-provided masks and place them in the focal plane with high accuracy. A complete mask exchange cycle is done in less than five minutes and can be run in every instrument position and state reducing instrument setup time during science observations to a minimum. Exchange of old and new MOS masks is likewise done under cryogenic conditions using a unique exchange drive mechanism and two auxiliary cryostats that attach to the main instrument cryostat.
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- 2010
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20. LUCIFER1: performance results
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Marcus Jütte, Rainer Lenzen, Holger Mandel, Clemens Storz, A. Germeroth, Ulrich Mall, Anna Pasquali, C. Feiz, Hans Gemperlein, Peter Buschkamp, P. Weiser, Peter Müller, Walter Seifert, L. Schäffner, Kai Lars Polsterer, Werner Laun, Andreas Quirrenbach, M. Lehmitz, Reiner Hofmann, R. Lederer, Volker Knierim, Nancy Ageorges, and Vianak Naranjo
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Physics ,business.industry ,System of measurement ,Optical instrument ,Near-infrared spectroscopy ,Large Binocular Telescope ,law.invention ,Telescope ,Optics ,Software ,law ,Calibration ,business ,Spectrograph - Abstract
LUCIFER1 is a NIR camera and spectrograph installed at the Large Binocular Telescope (LBT). Working in the wavelength range of 0.9-2.5micron, the instrument is designed for direct imaging and spectroscopy with 3 different cameras. A set of longslit masks as well as up to 23 user defined (MOS) masks are available. The set of user defined masks can be exchanged while the instrument is at operating temperature. Extensive tests have been done on the electro-mechanical functions, image motion due to flexure, optical quality, instrument software, calibration and especially on the multi-object spectroscopy. Also a detailed characterization of the instrument's properties in the different observing modes has been carried out. Results are presented and compared to the specifications.
- Published
- 2010
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21. The SINS Survey: Broad Emission Lines in High-Redshift Star-Forming Galaxies
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Shy Genel, Dieter Lutz, Erin K. S. Hicks, Nicolas Bouché, Richard I. Davies, Linda J. Tacconi, Emanuele Daddi, Alice E. Shapley, Eliot Quataert, Alvio Renzini, Charles C. Steidel, Andrea Cimatti, Simon J. Lilly, Amiel Sternberg, Dawn K. Erb, Frank Eisenhauer, Peter Buschkamp, Lee Armus, Natascha M. Förster Schreiber, Reinhard Genzel, Giovanni Cresci, Kristen L. Shapiro, Shapiro Kristen L., Genzel Reinhard, Quataert Eliot, Förster Schreiber Natascha M., Davies Richard, Tacconi Linda, Armus Lee, Bouché Nicola, Buschkamp Peter, Cimatti Andrea, Cresci Giovanni, Daddi Emanuele, Eisenhauer Frank, Erb Dawn K., Genel Shy, Hicks Erin K. S., Lilly Simon J., Lutz Dieter, Renzini Alvio, Shapley Alice, Steidel Charles C., and Sternberg Amiel
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Physics ,Supermassive black hole ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxy ,Redshift ,Spectral line ,Luminosity ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Emission spectrum ,Astrophysics::Galaxy Astrophysics ,Line (formation) ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
High signal-to-noise, representative spectra of star-forming galaxies at z~2, obtained via stacking, reveal a high-velocity component underneath the narrow H-alpha and [NII] emission lines. When modeled as a single Gaussian, this broad component has FWHM > 1500 km/s; when modeled as broad wings on the H-alpha and [NII] features, it has FWHM > 500 km/s. This feature is preferentially found in the more massive and more rapidly star-forming systems, which also tend to be older and larger galaxies. We interpret this emission as evidence of either powerful starburst-driven galactic winds or active supermassive black holes. If galactic winds are responsible for the broad emission, the observed luminosity and velocity of this gas imply mass outflow rates comparable to the star formation rate. On the other hand, if the broad line regions of active black holes account for the broad feature, the corresponding black holes masses are estimated to be an order of magnitude lower than those predicted by local scaling relations, suggesting a delayed assembly of supermassive black holes with respect to their host bulges., 11 pages, 5 figures. Accepted version, incorporating referee comments, including changes to title, abstract, figures, and discussion section
- Published
- 2009
22. LUCIFER status report: summer 2008
- Author
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Jochen Heidt, Dominik J. Bomans, Holger Mandel, Andreas Quirrenbach, Harald Weisz, Rainer Lenzen, P. Weiser, Ralf-Jürgen Dettmar, Volker Knierim, Reiner Hofmann, Hans Gemperlein, Florian Schwind, Lutz Geuer, Walter Seifert, Nancy Ageorges, Kai Lars Polsterer, Vianac Naranjo, Ulrich Mall, C. Feiz, Peter Müller, A. Germeroth, Marcus Jütte, L. Schäffner, Peter Buschkamp, Werner Laun, and M. Lehmitz
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Physics ,Cryostat ,biology ,business.industry ,Instrumentation ,Near-infrared spectroscopy ,biology.organism_classification ,law.invention ,Telescope ,Optics ,law ,business ,Spectroscopy ,Secondary mirror ,Spectrograph ,Lucifer ,Remote sensing - Abstract
LUCIFER is a NIR spectrograph and imager (wavelength range 0.9 to 2.5 micron) for the Large BinocularTelescope (LBT) on Mt. Graham, Arizona, working at cryogenic temperatures of less than 70K. Two instrumentsare built by a consortium of ve German institutes and will be mounted at the bent Gregorian foci of the twoindividual telescope mirrors. Three exchangable cameras are available for imaging and spectroscopy: two ofthem are optimized for seeing-limited conditions, a third camera for the diraction limited case will be used withthe LBT adaptive secondary mirror working. Up to 33 exchangeable masks are available for longslit or multi-object spectroscopy (MOS) over the full eld of vie w (FOV). Both MOS-units (LUCIFER 1 and LUCIFER2) and the auxiliary cryostats together with the control electronics have been completed. The observationalsoftware-package is in its nal stage of preparation.After the total integration of LUCIFER 1 extensive tes ts were done for all electro-mechanical functions andthe verication of the instrument started. The results of the tests are presented in detail and are compared withthe specications.Keywords: Instrumentation, Infrared, Testing, Multi-Object Spectroscopy, Cryogenic Mechanisms
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- 2008
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23. Mergers and Mass Accretion Rates in Galaxy Assembly: The Millennium Simulation Compared to Observations of z~2 Galaxies
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N. M. Förster Schreiber, Reinhard Genzel, Amiel Sternberg, K. Shapiro, Linda J. Tacconi, Giovanni Cresci, Peter Buschkamp, Shy Genel, Dieter Lutz, E. K. S. Hicks, T. Naab, Nicolas Bouché, and Ric Davies
- Subjects
Physics ,Star formation ,Astrophysics (astro-ph) ,Secular evolution ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Accretion (astrophysics) ,Galaxy ,Baryon ,Observational evidence ,Space and Planetary Science ,Elliptical galaxy ,Halo ,Astrophysics::Galaxy Astrophysics - Abstract
Recent observations of UV-/optically selected, massive star forming galaxies at z~2 indicate that the baryonic mass assembly and star formation history is dominated by continuous rapid accretion of gas and internal secular evolution, rather than by major mergers. We use the Millennium Simulation to build new halo merger trees, and extract halo merger fractions and mass accretion rates. We find that even for halos not undergoing major mergers the mass accretion rates are plausibly sufficient to account for the high star formation rates observed in z~2 disks. On the other hand, the fraction of major mergers in the Millennium Simulation is sufficient to account for the number counts of submillimeter galaxies (SMGs), in support of observational evidence that these are major mergers. When following the fate of these two populations in the Millennium Simulation to z=0, we find that subsequent mergers are not frequent enough to convert all z~2 turbulent disks into elliptical galaxies at z=0. Similarly, mergers cannot transform the compact SMGs/red sequence galaxies at z~2 into observed massive cluster ellipticals at z=0. We argue therefore, that secular and internal evolution must play an important role in the evolution of a significant fraction of z~2 UV-/optically and submillimeter selected galaxy populations., Comment: 5 pages, 4 figures, Accepted for publication in ApJ
- Published
- 2008
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24. Go Long, Go Deep: Finding Optical Jet Breaks for Swift-Era GRBs with the LBT
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Xiaohui Fan, Peter Buschkamp, Krzysztof Z. Stanek, E. Giallongo, Linhua Jiang, David R. Thompson, Roberto Ragazzoni, Riccardo Smareglia, John M. Hill, J. L. Prieto, Nicolas Bouché, Xinyu Dai, Christopher S. Kochanek, Roland Gredel, Fernando Pedichini, Peter M. Garnavich, Robert Wagner, Peter Milne, James E. Rhoads, Jill Bechtold, Richard W. Pogge, E. Diolaiti, and C. McClellend
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Physics ,Jet (fluid) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Large Binocular Telescope ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Light curve ,Galaxy ,Collimated light ,Afterglow ,Supernova ,Space and Planetary Science ,Gamma-ray burst - Abstract
Using the 8.4m Large Binocular Telescope, we observed six GRB afterglows from 2.8 hours to 30.8 days after the burst triggers to systematically probe the late time behaviors of afterglows including jet breaks, flares, and supernova bumps. We detected five afterglows with Sloan r' magnitudes ranging from 23.0-26.3 mag. The depth of our observations allows us to extend the temporal baseline for measuring jet breaks by another decade in time scale. We detected two jet breaks and a third candidate, all of which are not detectable without deep, late time optical observations. In the other three cases, we do not detect the jet breaks either because of contamination from the host galaxy light, the presence of a supernova bump, or the intrinsic faintness of the optical afterglow. This suggests that the basic picture that GRBs are collimated is still valid and that the apparent lack of Swift jet breaks is due to poorly sampled afterglow light curves, particularly at late times., Accepted by ApJ Letters, 14 pages, 2 figures
- Published
- 2007
25. INFRARED NARROWBAND TOMOGRAPHY OF THE LOCAL STARBURST NGC 1569 WITH THE LARGE BINOCULAR TELESCOPE/LUCIFER
- Author
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L. Schaeffner, Kai Lars Polsterer, Anna Pasquali, H. W. Rix, Ulrich Mall, R. Lederer, C. Feiz, A. Germeroth, Arjan Bik, Hans Gemperlein, Nancy Ageorges, M. Lehmitz, Holger Mandel, Clemens Storz, A. Quirrenbach, Wolfgang Brandner, Peter Buschkamp, Stefano Zibetti, R. Hoffmann, Volker Knierim, Werner Laun, Marcus Juette, P. Mueller, Vianak Naranjo, P. Weiser, Walter Seifert, and Rainer Lenzen
- Subjects
Physics ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,Extinction (astronomy) ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Luminosity ,Interstellar medium ,Stars ,Supernova ,Star cluster ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We used the near-IR imager/spectrograph LUCIFER mounted on the Large Binocular Telescope (LBT) to image, with sub-arcsec seeing, the local dwarf starburst NGC 1569 in the JHK bands and HeI 1.08 micron, [FeII] 1.64 micron and Brgamma narrow-band filters. We obtained high-quality spatial maps of HeI, [FeII] and Brgamma emission across the galaxy, and used them together with HST/ACS images of NGC 1569 in the Halpha filter to derive the two-dimensional spatial map of the dust extinction and surface star formation rate density. We show that dust extinction is rather patchy and, on average, higher in the North-West (NW) portion of the galaxy [E_g(B-V) = 0.71 mag] than in the South-East [E_g(B-V) = 0.57 mag]. Similarly, the surface density of star formation rate peaks in the NW region of NGC 1569, reaching a value of about 4 x 10^-6 M_sun yr^-1 pc^-2. The total star formation rate as estimated from the integrated, dereddened Halpha luminosity is about 0.4 M_sun yr^-1, and the total supernova rate from the integrated, dereddened [FeII] luminosity is about 0.005 yr^-1 (assuming a distance of 3.36 Mpc). The azimuthally averaged [FeII]/Brgamma flux ratio is larger at the edges of the central, gas-deficient cavities (encompassing the super star clusters A and B) and in the galaxy outskirts. If we interpret this line ratio as the ratio between the average past star formation (as traced by supernovae) and on-going activity (represented by OB stars able to ionize the interstellar medium), it would then indicate that star formation has been quenched within the central cavities and lately triggered in a ring around them. The number of ionizing hydrogen and helium photons as computed from the integrated, dereddened Halpha and HeI luminosities suggests that the latest burst of star formation occurred about 4 Myr ago and produced new stars with a total mass of ~1.8 x 10^6 M_sun. [Abridged]
- Published
- 2011
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26. Multicolor Single-Molecule Spectroscopy with Alternating Laser Excitation for the Investigation of Interactions and Dynamics.
- Author
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Joachim Ross, Peter Buschkamp, Daniel Fetting, Achim Donnermeyer, Christian M. Roth, and Philip Tinnefeld
- Subjects
- *
NUCLEIC acids , *SPECTRUM analysis , *ENERGY storage , *ENERGY transfer - Abstract
We have developed confocal multicolor single-molecule spectroscopy with optimized detection sensitivity on three spectrally distinct channels for the study of biomolecular interactions and FRET between more than two molecules. Using programmable acousto-optical devices as beamsplitter and excitation filter, we overcome some of the limitations of conventional multichroic beamsplitters and implement rapid alternation between three laser lines. This enables to visualize the synthesis of DNA three-way junctions on a single-molecule basis and to resolve seven stoichiometric subpopulations as well as to quantify FRET in the presence of competing energy transfer pathways. Furthermore, the ability to study correlated molecular movements by monitoring several distances within a biomolecular complex simultaneously is demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
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