An early-time infrared and optical study of the Type Ia Supernova 1998bu in M96     

M. Hernandez  W. P. S. Meikle  A. Aparicio  C. R. Benn  M. R. Burleigh  A. C. Chrysostomou  A. J. L. Fernandes  T. R. Geballe  P. L. Hammersley  J. Iglesias-Paramo  D. J. James  P. A. James  S. N. Kemp  T. A. Lister  D. Martinez-Delgado  A. Oscoz  D. L. Pollacco  M. Rozas  S. J. Smartt  P. Sorensen  R. A. Swaters  J. H. Telting  W. D. Vacca  N. A. Walton  M. R. Zapatero-Osorio 《Monthly notices of the Royal Astronomical Society》2000,319(1):223-234

We present first-season infrared (IR) and optical photometry and spectroscopy of the Type Ia Supernova 1998bu in M96. We also report optical polarimetry of this event. SN 1998bu is one of the closest type Ia supernovae of modern times, and the distance of its host galaxy is well determined. We find that SN 1998bu is both photometrically and spectroscopically normal. However, the extinction to this event is unusually high, with     We find that SN 1998bu peaked at an intrinsic     Adopting a distance modulus of 30.25 (Tanvir et al.) and using Phillips et al.'s relations for the Hubble constant, we obtain     Combination of our IR photometry with those of Jha et al. provides one of the most complete early-phase IR light curves for a SN Ia published so far. In particular, SN 1998bu is the first normal SN Ia for which good pre- t _{B max} IR coverage has been obtained. It reveals that the J , H and K light curves peak about 5 days earlier than the flux in the B -band curve.  相似文献   

Highly retentive core domains in K-feldspar and their implications for 40Ar/39Ar thermochronology illustrated by determining the cooling curve for the Capoas Granite,Palawan, The Philippines     

M. A. Forster  R. Armstrong  B. Kohn  G. S. Lister  M. A. Cottam  S. Suggate 《Australian Journal of Earth Sciences》2013,60(7):883-902

K-feldspar from the late Miocene Capoas Granite on Palawan in The Philippines appears to contain highly retentive diffusion domains that are closed to argon diffusion at near-solidus temperatures during cooling of this ～7 km-diameter pluton. This is an important result, for K-feldspar is commonly considered not retentive in terms of its ability to retain argon. Closure temperatures for argon diffusion in K-feldspars are routinely claimed to be in the range ～150–400°C but the release of ³⁹Ar from irradiated K-feldspar during furnace step-heating experiments in vacuo yields Arrhenius data that imply the existence of highly retentive core domains, with inferred closure temperatures that can exceed ～500–700°C. These high closure temperatures from the Capoas Granite K-feldspar are consistent with the coincidence of ⁴⁰Ar/³⁹Ar ages with U–Pb zircon ages at ca 13.5 ± 0.2 Ma. The cooling rate then accelerated, but the rate of change had considerably slowed by ca 12 Ma. Low-temperature (U–Th)/He thermochronology shows that the cooling rate once again accelerated at ca 11 Ma, perhaps owing to renewed tectonic activity.  相似文献   

Structure of the Mt Isa region from seismic ambient noise tomography     

E. Saygin  H. McQUEEN  L. J. Hutton  B. L. N. Kennett  G. Lister 《Australian Journal of Earth Sciences》2013,60(6-7):707-718

We use seismic tomography, exploiting group velocities derived from ambient noise, to delineate the crustal structure beneath Mt Isa and the surrounding blocks and basins. The depth extent of the blocks can be traced into the mid-crust and the spatial extent of the associated velocity anomalies mapped over an area of approximately 500 km by 500 km. The Proterozoic Mt Isa block is imaged as a region of elevated seismic velocities comparable to the Yilgarn craton in Western Australia, while the surrounding basins have relatively low velocities. Seismic velocity anomalies display correlations with the regional Bouguer gravity data and with high crustal temperatures in the region. There are a number of isolated low-velocity anomalies under the Millungera basin that suggest either previously unknown thermal anomalies or zones with high permeability, which can also produce lowered velocities.  相似文献   

Woolly mammoth (Mammuthus primigenius Blum.) and its environment in northern Europe during the last glaciation     

P. Ukkonen  K. Aaris-Sørensen  L. Arppe  P.U. Clark  L. Daugnora  A.M. Lister  L. Lõugas  H. Seppä  R.S. Sommer  A.J. Stuart  P. Wojtal  I. Zupiņš 《Quaternary Science Reviews》2011,30(5-6):693-712

Woolly mammoths were large, herbivorous, cold-adapted mammals of the Late Pleistocene. The diet and habitat requirements of the species set certain constraints on the palaeoenvironments it could occupy. The relationship between the mammoth’s shifting range and changing environments can be explored using independent data on ice sheet configuration, temperature, and vegetation, provided the locality and age of the fossil remains can be validated. Here we present a comprehensive record of occurrence of the woolly mammoth in the circum-Baltic region of northern Europe during the last glaciation, based on a compilation of radiocarbon-dated remains. The record shows that the mammoth was widespread in northern and north-eastern Europe during Marine Isotope Stage 3 (MIS 3), at 50,000–30,000 calibrated years ago (50–30 ka). The presence of the species up to 65°N latitude supports the restriction of the Scandinavian Ice Sheet (SIS) during MIS 3. The widest distribution range round 30 ka was followed by a decline that led to the disappearance of mammoths from the area during the maximum extent of the SIS, from 22 to 18 ka. The woolly mammoth re-colonized the Baltic region and southern Scandinavia after the onset of the late-glacial deglaciation at 17 ka. The late-glacial record suggests a markedly fluctuating population changing its range in tune with the rapid environmental changes. The last appearance of mammoth in our study region was in Estonia during the Younger Dryas (Greenland Stadial 1; GS1) at about 12 ka. The two major periods of occurrence during MIS 3 and the late-glacial stadial suggest that mammoth had a wide tolerance of open to semi-open tundra and steppe-tundra habitats with intermediately cold climate, whereas the 22–18 ka disappearance suggests a major southward and/or eastward retreat in response to extremely cold, glacial conditions near the SIS margin. The final regional extinction correlates with the re-forestation during the rapid warming at the Younger Dryas–Holocene boundary.  相似文献   

Efficient identification of exoplanetary transit candidates from SuperWASP light curves     

A. Collier Cameron  D. M. Wilson  R. G. West  L. Hebb  X.-B. Wang  S. Aigrain  F. Bouchy  D. J. Christian  W. I. Clarkson  B. Enoch  M. Esposito  E. Guenther  C. A. Haswell  G. Hébrard  C. Hellier  K. Horne  J. Irwin  S. R. Kane  B. Loeillet  T. A. Lister  P. Maxted  M. Mayor  C. Moutou  N. Parley  D. Pollacco  F. Pont  D. Queloz  R. Ryans  I. Skillen  R. A. Street  S. Udry  P. J. Wheatley 《Monthly notices of the Royal Astronomical Society》2007,380(3):1230-1244

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LO Peg in 1998: star-spot patterns and differential rotation     

J. R. Barnes  A. Collier Cameron  T. A. Lister  G. R. Pointer  M. D. Still 《Monthly notices of the Royal Astronomical Society》2005,356(4):1501-1508

We present Doppler images of the young K5V–K7V rapid rotator LO Peg from seven nights of continuous spectroscopy obtained in 1998 from July 04 to July 10. The images reveal the presence of a strong polar cap with appendages extending to mid-latitudes, but no star-spots are seen below 15°. We briefly discuss the distribution of spots in light of recent flux transport simulations, which are able to reproduce the observed latitude dependence. With the full time series of spectra, of which 314 are useful, many phases are observed three times over the seven nights of observations. Using star-spots as tracers of a solar-like latitudinal differential rotation in our image reconstructions, we find that the equatorial regions complete one more rotation than the polar regions every  181 ± 35 d  . LO Peg is the second coolest star for which such a measurement has been made using indirect imaging methods. The degree of latitudinal shear is less than that seen in G and early K dwarfs, suggesting a trend in which differential rotation decreases with stellar mass in (pre-)main-sequence objects.  相似文献   

Discovery of a precessing jet nozzle in BL Lacertae     

A. M. Stirling  T. V. Cawthorne  J. A. Stevens  S. G. Jorstad  A. P. Marscher  M. L. Lister  J. L. Gómez  P. S. Smith  I. Agudo  D. C. Gabuzda  E. I. Robson  W. K. Gear 《Monthly notices of the Royal Astronomical Society》2003,341(2):405-422

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The column density distribution function at z= 0 from H i selected galaxies     

Emma V. Ryan-Weber  Rachel L. Webster  Lister Staveley-Smith 《Monthly notices of the Royal Astronomical Society》2003,343(4):1195-1206

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Interacting supergiant shells in the Large Magellanic Cloud     

Martin Cohen  Lister Staveley-Smith  Anne Green 《Monthly notices of the Royal Astronomical Society》2003,340(1):275-283

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The SuperWASP wide-field exoplanetary transit survey: candidates from fields 23 h < RA < 03 h     

D. J. Christian  D. L. Pollacco  I. Skillen  R. A. Street  F. P. Keenan  W. I. Clarkson  A. Collier Cameron  S. R. Kane  T. A. Lister  R. G. West  B. Enoch  A. Evans  A. Fitzsimmons  C. A. Haswell  C. Hellier  S. T. Hodgkin  K. Horne  J. Irwin  A. J. Norton  J. Osborne  R. Ryans  P. J. Wheatley  D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2006,372(3):1117-1128

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