The star formation rate at redshift one: Hα spectroscopy with CIRPASS     

Michelle Doherty  rew Bunker  Robert Sharp  Gavin Dalton  Ian Parry  Ian Lewis 《Monthly notices of the Royal Astronomical Society》2006,370(1):331-342

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Star formation through gravitational collapse and competitive accretion     

Ian A. Bonnell  Matthew R. Bate 《Monthly notices of the Royal Astronomical Society》2006,370(1):488-494

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Rest-frame optical and far-infrared observations of extremely bright Lyman-break galaxy candidates at z∼ 2.5     

R. J. Ivison  Ian Smail  Misty Bentz  J. A. Stevens  K. Menéndez-Delmestre  S. C. Chapman  A. W. Blain 《Monthly notices of the Royal Astronomical Society》2005,362(2):535-541

We have investigated the rest-frame optical and far-infrared properties of a sample of extremely bright candidate Lyman-break galaxies (LBGs) identified in the Sloan Digital Sky Survey. Their high ultraviolet luminosities and lack of strong ultraviolet emission lines are suggestive of massive starbursts, although it is possible that they are more typical luminosity LBGs which have been highly magnified by strong gravitational lensing. Alternatively, they may be an unusual class of weak-lined quasars. If the ultraviolet and submillimetre (submm) properties of these objects mirror those of less luminous, starburst LBGs, then they should have detectable rest-frame far-infrared emission. However, our submm photometry fails to detect such emission, indicating that these systems are not merely scaled-up (either intrinsically or as a result of lensing) examples of typical LBGs. In addition we have searched for the morphological signatures of strong lensing, using high-resolution, near-infrared imaging, but we find none. Instead, near-infrared spectroscopy reveals that these systems are, in fact, a rare class of broad absorption line quasars.  相似文献   

Traditional Pastoral Life In Romania*     

Ian M. Matley 《The Professional geographer》1970,22(6):311-316

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Architecture and evolution of a fjord‐head delta,western Vancouver Island,British Columbia     

Jeffrey E. Gutsell  John J. Clague  Melvyn E. Best  Peter T. Bobrowsky  Ian Hutchinson 《第四纪科学杂志》2004,19(5):497-511

The architectural framework and Holocene evolution of the Zeballos fjord‐head delta on west‐central Vancouver Island was established through a multidisciplinary field‐based study. The Zeballos delta is a composite feature, consisting of an elevated, incised, late Pleistocene delta and an inset Holocene delta graded to present sea level. Both deltas have a classic Gilbert‐type tripartite architecture, with nearly flat topset and bottomset units and an inclined foreset unit. Time domain electromagnetic (TDEM) and ground‐penetrating radar (GPR) surveys, borehole data, and gravel pit exposures provided information on the internal form, lithologies and substrate of both deltas. Both sets of deltaic deposits coarsen upward from silt in the bottomset unit to gravel in the topset unit. The TDEM survey revealed a highly irregular, buried bedrock surface, ranging from 20 m to 190 m in depth, and it delineated saltwater intrusion into the deltaic sediments. Late Quaternary sea‐level change at Zeballos was inferred from delta morphology and the GPR survey. The elevated, late Pleistocene delta was constructed when the sea was about 21 m higher relative to the land than it is today. It was dissected when sea‐level fell rapidly as a result of glacio‐isostatic rebound. Relative sea‐level reached a position about 20 m below the present datum during the early Holocene. Foreset beds that overlap and progressively climb in a seaward direction and topset beds that thicken to 26 m landward imply that the delta aggraded and prograded into Zeballos Inlet during the middle and late Holocene transgression. Sea‐level may have risen above the present datum during the middle Holocene, creating a delta plain at about 4 m a.s.l. Remnants of this surface are preserved along the valley margins. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Correlation of atmospheric opacity measurements by SCUBA and an infrared radiometer     

Ian M. Chapman  David A. Naylor  Robin R. Phillips 《Monthly notices of the Royal Astronomical Society》2004,354(2):621-628

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Galaxy groups in the 2dFGRS: the group-finding algorithm and the 2PIGG catalogue     

V. R. Eke  Carlton M. Baugh  Shaun Cole  Carlos S. Frenk  Peder Norberg  John A. Peacock  Ivan K. Baldry  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Karl Glazebrook  Carole Jackson  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren Madgwick  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,348(3):866-878

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Basaltic diversity at the Apollo 12 landing site: Inferences from petrologic examinations of the soil sample 12003     

Joshua F. Snape  Katherine H. Joy  Ian A. Crawford  Louise Alexander 《Meteoritics & planetary science》2014,49(5):842-871

A detailed petrologic survey has been made of 17 basaltic chips (sized between 1 and 10 mm) from the 12003 soil sample as part of an ongoing study of basaltic diversity at the Apollo 12 landing site. An attempt has been made to classify these samples according to the well‐established grouping of olivine, pigeonite, ilmenite, and feldspathic basalts. Particular attention has been paid to variations in major, minor, and trace element mineral chemistry (determined by electron microprobe analysis and laser ablation ICP‐MS), which may be indicative of particular basaltic suites and less susceptible to sampling bias than bulk sample characteristics. Examples of all three main (olivine, pigeonite, and ilmenite) basaltic suites have been identified within the 12003 soil. One sample is identified as a possible new addition to the feldspathic suite, which currently consists of only one other confirmed sample. Identification of additional feldspathic basalts strengthens the argument that they represent a poorly sampled basaltic flow local to the Apollo 12 site, rather than exotic material introduced to the site by impact mixing processes. Three samples are identified as representing members of one or two previously unrecognized basaltic suites.  相似文献   

Validation of synoptic circulation patterns simulated by the Canadian climate centre general circulation model for western north America: Research note     

Ian G. McKendry  Douw G. Steyn  Gordon McBean 《大气与海洋》2013,51(4):809-825

Abstract

In order to assess the ability of a GCM to simulate regional to synoptic scale atmospheric structures, a correlation‐based computer‐assisted gridded map typing procedure is used to compare daily pressure (MSL) and geopotential height fields (500 hPa) from a GCM simulation of the present climate to a decade of NMC analyses. The model is able to reproduce the entire range of synoptic circulation types. However, statistically significant differences in the seasonal frequencies and variances of the main circulation types are evident. These differences, which are most pronounced in the winter (at 500 hPa) and in spring and autumn in the MSL fields, are consistent with subtle errors in the predicted fields at the hemispheric scale. The lack of agreement between the NMC climatology and the “control” simulation precludes extension of this approach to investigation of climate change impacts in western north America, and to more meteorologically dynamic extra‐tropical regions. The map‐typing procedure is shown to be an appropriate GCM synoptic‐scale validation tool that permits direct comparison of GCM output and observed fields. As such, it has the potential to elucidate the regional‐scale impacts of global climatic change through established synoptic circulation environment relationships.  相似文献   

Climate change simulated by full and mixed-layer ocean versions of CSIRO Mk3.5 and Mk3.0: Large-scale sensitivity   总被引：1，自引：0，他引：1  

Ian G. Watterson  Siobhan P. O’Farrell 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(3):375-387

The CSIRO Mk3.5 coupled atmosphere-ocean model includes upgrades to atmospheric and oceanic processes that remove a cold bias of the earlier Mk3.0. The global mean warming over the 21st century from Mk3.5 is 3.1 K under the CMIP3 A1B scenario, some 25% larger than that from Mk3.0. Two mixed-layer ocean versions of Mk3.5 were constructed, and these are also more sensitive than Mk3.0. To elucidate these differences, a simple feedback analysis is extended to Mk3.5, using changes for doubled CO₂ in each model version. The net feedback for the low-mid latitude region is the main driver of the sensitivity contrast. The clear-sky component is consistently larger in Mk3.5, as is the increase in specific humidity, even after standardizing by the global warming. Cloud forcing provides a small positive feedback, which is stronger in cases that had larger declines in low-layer cloud. The net positive feedback for the higher-latitude region is larger in the coupled Mk3.5 than Mk3.0, which had more stable Arctic sea ice. However, some contrasts differed among the versions. As for Mk3.0, the surface warming in the coupled Mk3.5 is suppressed over that from the MLO case. Over the ocean, the pattern of suppression is similar to the change in energy flux into the surface in the coupled model. There is also a gradient of equatorial warming in the Asia-Pacific region that relates to the change in net convergence of heat transport by ocean currents. The effect of this pattern on regional rainfall is a focus of Part 2 of the study.  相似文献