The STAGES view of red spirals and dusty red galaxies: mass-dependent quenching of star formation in cluster infall     

Christian Wolf  Alfonso Aragón-Salamanca  Michael Balogh  Marco Barden  Eric F. Bell  Meghan E. Gray  Chien Y. Peng  David Bacon  Fabio D. Barazza  Asmus Böhm  John A. R. Caldwell  Anna Gallazzi  Boris Häußler  Catherine Heymans  Knud Jahnke  Shardha Jogee  Eelco van Kampen  Kyle Lane  Daniel H. McIntosh  Klaus Meisenheimer  Casey Papovich  Sebastian F. Sánchez  y Taylor  Lutz Wisotzki  Xianzhong Zheng 《Monthly notices of the Royal Astronomical Society》2009,393(4):1302-1323

We investigate the properties of optically passive spirals and dusty red galaxies in the A901/2 cluster complex at redshift ∼0.17 using rest-frame near-ultraviolet–optical spectral energy distributions, 24-μm infrared data and Hubble Space Telescope morphologies from the STAGES data set. The cluster sample is based on COMBO-17 redshifts with an rms precision of  σ _cz ≈ 2000 km s⁻¹  . We find that 'dusty red galaxies' and 'optically passive spirals' in A901/2 are largely the same phenomenon, and that they form stars at a substantial rate, which is only four times lower than that in blue spirals at fixed mass. This star formation is more obscured than in blue galaxies and its optical signatures are weak. They appear predominantly in the stellar mass range of  log  M _*/M_⊙=[10, 11]  where they constitute over half of the star-forming galaxies in the cluster; they are thus a vital ingredient for understanding the overall picture of star formation quenching in clusters. We find that the mean specific star formation rate (SFR) of star-forming galaxies in the cluster is clearly lower than in the field, in contrast to the specific SFR properties of blue galaxies alone, which appear similar in cluster and field. Such a rich red spiral population is best explained if quenching is a slow process and morphological transformation is delayed even more. At  log  M _*/M_⊙ < 10  , such galaxies are rare, suggesting that their quenching is fast and accompanied by morphological change. We note that edge-on spirals play a minor role; despite being dust reddened they form only a small fraction of spirals independent of environment.  相似文献   

The rise and fall of galaxy activity in dark matter haloes     

Anna Pasquali  Frank C. van den Bosch  H. J. Mo  Xiaohu Yang  Rachel Somerville 《Monthly notices of the Royal Astronomical Society》2009,394(1):38-50

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Pedogenetic processes coeval with Neogene faults evolution in the Barcelona's Plain,NE Spain     

Irene Cantarero  Anna Travé  Gemma Alías 《Journal of Geochemical Exploration》2009

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The Method of Measurements of Celestial Coordinates in Wide-Field TV-Frames     

Anna P. Kartashova 《Earth, Moon, and Planets》2012,108(3-4):165-173

We present a method for calculations of equatorial coordinates of any point in the single frame of the wide-field TV systems. This method can be applying for the different television systems [wide-field cameras, all-sky cameras, the cameras with the hybrid TV-system (the system with coupled of the Image Intensifier) et al.]. In that system the calculations of distortions are difficult. Therefore, we devised this method which helps decrease errors (due to distortion and the electro-optical system).The method can be used for measuring of equatorial coordinates of meteor tracks under difficult conditions during the observations such as partial cloudiness, small number of stars and large distortions of the coordinate grid in the frame. These restrictions cannot be overcome by other methods. In the case of the small number of stars the present method using of the reference stars received on a series of frames during the observation period. The accuracy of the method has been estimated to be 4′–8′ (for cameras with fov 50°?×?40° at the CCD 720?×?576 pixels) for maximum number of reference points in the frame. The method used 3 reference points for calculation of the equatorial coordinates of the object. One can use this method if the camera was re-oriented as well. We use this method for our wide field of view cameras.  相似文献   

Subarctic catchment water storage and carbon cycling – Leading the way for future studies using integrated datasets at Pallas,Finland     

Hannu Marttila  Annalea Lohila  Pertti Ala-Aho  Kashif Noor  Jeffrey M. Welker  Danny Croghan  Kaisa Mustonen  Leo-Juhani Meriö  Anna Autio  Filip Muhic  Hannah Bailey  Mika Aurela  Jussi Vuorenmaa  Timo Penttilä  Valtteri Hyöky  Eric Klein  Anton Kuzmin  Pasi Korpelainen  Timo Kumpula  Anssi Rauhala  Bjørn Kløve 《水文研究》2021,35(9):e14350

Subarctic ecohydrological processes are changing rapidly, but detailed and integrated ecohydrological investigations are not as widespread as necessary. We introduce an integrated research catchment site (Pallas) for atmosphere, ecosystems, and ecohydrology studies in subarctic conditions in Finland that can be used for a new set of comparative catchment investigations. The Pallas site provides unique observational data and high-intensity field measurement datasets over long periods. The infrastructure for atmosphere- to landscape-scale research in ecosystem processes in a subarctic landscape has recently been complemented with detailed ecohydrological measurements. We identify three dominant processes in subarctic ecohydrology: (a) strong seasonality drives ecohydrological regimes, (b) limited dynamic storage causes rapid stream response to water inputs (snowmelt and intensive storms), and (c) hydrological state of the system regulates catchment-scale dissolved carbon dynamics and greenhouse (GHG) fluxes. Surface water and groundwater interactions play an important role in regulating catchment-scale carbon balances and ecosystem respiration within subarctic peatlands, particularly their spatial variability in the landscape. Based on our observations from Pallas, we highlight key research gaps in subarctic ecohydrology and propose several ways forward. We also demonstrate that the Pallas catchment meets the need for sustaining and pushing the boundaries of critical long-term integrated ecohydrological research in high-latitude environments.  相似文献   

Lensing, reddening and extinction effects of Mg ii absorbers from z= 0.4 to 2     

Brice Ménard  Daniel Nestor  David Turnshek  Anna Quider  Gordon Richards  Doron Chelouche  Sandhya Rao 《Monthly notices of the Royal Astronomical Society》2008,385(2):1053-1066

Using a sample of almost 7000 strong Mg  ii absorbers with   W ₀ > 1 Å  and  0.4 < z < 2.2  detected in the SDSS DR4 data set, we investigate the gravitational lensing and dust extinction effects they induce on background quasars. After carefully quantifying several selection biases, we isolate the reddening effects as a function of redshift and absorber rest equivalent width, W ₀. We find the amount of dust to increase with cosmic time as  τ( z ) ∝ (1 + z )^−1.1±0.4  , following the evolution of cosmic star density or integrated star formation rate. We measure the reddening effects over a factor of 30 in E ( B − V ) and we find that  τ∝ ( W ₀)^1.9±0.1  , providing us with an important scaling for theoretical modelling of metal absorbers. We also measure the dust-to-metal ratio and find it similar to that of the Milky Way. In contrast to previous studies, we do not detect any gravitational magnification by Mg  ii systems. We measure the upper limit  μ < 1.10  and discuss the origin of the discrepancy. Finally, we estimate the fraction of absorbers missed due to extinction effects and show that it rises from 1 to 50 per cent in the range  1 < W ₀ < 6 Å  . We parametrize this effect and provide a correction for recovering the intrinsic  ∂ N /∂ W ₀  distribution.  相似文献   

Mantle source heterogeneity in subduction zones: constraints from elemental and isotope (Sr,Nd, and Pb) data on Vulcano Island,Aeolian Archipelago,Italy     

Pinarelli  Laura  Gioncada  Anna  Capaccioni  Bruno  Vaselli  Orlando  Downes  Hilary 《Mineralogy and Petrology》2019,113(1):39-60

Mineralogy and Petrology - Vulcano is part of the Aeolian volcanic arc in the southern Tyrrhenian Sea. Its products were emplaced through multiple episodes of edifice building and collapse since...  相似文献   

High-Nb hawaiite–mugearite and high-Mg calc-alkaline lavas from northeastern Iran: Oligo-Miocene melts from modified mantle wedge     

Parham Ahmadi  Massimo Coltorti  Takeshi Kuritani  Yue Cai  Anna Maria Fioretti 《International Geology Review》2019,61(2):150-174

Tertiary volcanic rocks in northwestern Firoozeh, Iran (the Meshkan triangular structural unit), constitute vast outcrops (up to 250 km²) of high-Mg basaltic andesites to dacites that are associated with high-Nb hawaiites and mugearites. Whole-rock ⁴⁰Ar/³⁹Ar ages show a restricted range of 24.1 ± 0.4–22.9 ± 0.5 Ma for the volcanic rocks. The initial ratios of ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd vary from 0.703800 to 0.704256 and 0.512681 to 0.512877, respectively, in the high-Mg basaltic andesites–dacites. High-Th contents (up to 11 ppm) and Sr/Y values (27–100) and the isotopic composition of the subalkaline high-Mg basaltic andesites–dacites indicate derivation from a mantle modified by slab and sediment partial melts. Evidence such as reverse zoning and resorbed textures and high Ni and Cr contents in the evolved samples indicate that magma mixing with mafic melts and concurrent fractional crystallization lead to the compositional evolution of this series. The high-Nb hawaiites and mugearites, by contrast, have a sodic alkaline affinity and are silica undersaturated; they are also enriched in Nb (up to 47 ppm) and a wide range of incompatible trace elements, including LILE, LREE, and HFSE. Geochemistry and Sr–Nd isotopic compositions of the high-Nb hawaiites and mugearites suggest derivation from a mantle source affected by lower degrees of slab melts. Post-orogenic slab break-off is suggested to have prompted the asthenospheric upwelling that triggered partial melting in mantle metasomatized by slab-derived melts.  相似文献   

Mechanical interpretation of dry granular masses impacting on rigid obstacles     

Calvetti  Francesco  di Prisco  Claudio  Redaelli  Irene  Sganzerla  Anna  Vairaktaris  Emmanouil 《Acta Geotechnica》2019,14(5):1289-1305

Acta Geotechnica - The evaluation of impact forces exerted by flowing granular masses on rigid obstacles is of fundamental importance for the assessment of the associated risk and for the design of...  相似文献   

Late Pleistocene and Early Holocene lake‐level fluctuations in the Lahontan Basin,Nevada: Implications for the distribution of archaeological sites     

Kenneth D. Adams  Ted Goebel  Kelly Graf  Geoffrey M. Smith  Anna J. Camp  Richard W. Briggs  David Rhode 《Geoarchaeology》2008,23(5):608-643

The Great Basin of the western U.S. contains a rich record of Late Pleistocene and Holocene lake‐level fluctuations as well as an extensive record of human occupation during the same time frame. We compare spatial‐temporal relationships between these records in the Lahontan basin to consider whether lake‐level fluctuations across the Pleistocene‐Holocene transition controlled distribution of archaeological sites. We use the reasonably well‐dated archaeological record from caves and rockshelters as well as results from new pedestrian surveys to investigate this problem. Although lake levels probably reached maximum elevations of about 1230–1235 m in the different subbasins of Lahontan during the Younger Dryas (YD) period, the duration that the lakes occupied the highest levels was brief. Paleoindian and Early Archaic archaeological sites are concentrated on somewhat lower and slightly younger shorelines (_1220–1225 m) that also date from the Younger Dryas period. This study suggests that Paleoindians often concentrated their activities adjacent to large lakes and wetland resources soon after they first entered the Great Basin. © 2008 Wiley Periodicals, Inc.  相似文献