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二连盆地下古近系的磁性地层学研究 总被引：7，自引：0，他引：7
古地磁的测试结果表明,蒙古高原二连盆地努和廷勃尔和与呼和勃尔和地区剖面早古近纪地层共记录了5个正极性段与6个负极性段,通过与2004年标准极性年代表对比,确认其可与C21r-C26r之间的极性带对应。脑木根组以晚古新世沉积为主,同时接受了始新世最早期部分沉积及少许中古新世;阿山头组跨越了早—中始新世,持续时间较长;伊尔丁曼哈组的时代为中始新世。同时,确定了含Lambdopsalis,Prionessus及Palaeostylops的化石层的时代为晚古新世最早期;Gomphos层的年龄大致与古新世-始新世界线的年龄相当。 相似文献
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Alwyn Wootten 《Astrophysics and Space Science》2008,313(1-3):9-12
The Atacama Large Millimeter/submillimeter Array (ALMA) (The Enhanced Atacama Large Millimeter/submillimeter Array (known
as ALMA) is an international astronomy facility. ALMA is a partnership between North America, Europe, and Japan/Taiwan, in
cooperation with the Republic of Chile, and is funded in Europe by the European Southern Observatory (ESO) and Spain, in North
America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC), and
in Japan by the National Institutes of Natural Sciences (NINS) in cooperation with the Academia Sinica in Taiwan. ALMA construction
and operations are led on behalf of Japan/Taiwan by the National Astronomical Observatory of Japan (NAOJ), on behalf of North
America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI), and on
behalf of Europe by ESO) combines large collecting area and location on a high dry site to provide it with unparalleled potential
for sensitive millimeter/submillimeter spectral line observations. Its wide frequency coverage, superb receivers and flexible
spectrometer will ensure that its potential is met. Since the 1999 meeting on ALMA Science (Wootten, ASP Conf. Ser. 235, 2001), the ALMA team has substantially enhanced its capability for line observations. ALMA’s sensitivity increased when Japan
joined the project, bringing the 16 antennas of the Atacama Compcat Array (ACA), equivalent to eight additional 12 m telescopes.
The first four receiver cartridges for the baseline ALMA (Japan’s entry has brought two additional bands to ALMA’s receiver
retinue) have been accepted, with performance above the already-challenging specifications. ALMA’s flexibility has increased
with the enhancement of the baseline correlator with additional channels and flexibility, and with the addition of a separate
correlator for the ACA. As an example of the increased flexibility, ALMA is now capable of multi-spectral-region and multi-resolution
modes. With the former, one might observe e.g. four separate transitions anywhere within a 2 GHz band with a high resolution
bandwidth. With the latter, one might simultaneously observe with low spectral resolution over a wide bandwidth and with high
spectral resolution over a narrow bandwidth; this mode could be useful for observations of pressure-broadened lines with narrow
cores, for example. Several science examples illustrate ALMA’s potential for transforming millimeter and submillimeter astronomy. 相似文献
3.
T. L. Wilson 《Astrophysics and Space Science》2008,313(1-3):13-14
The Atacama Large Millimeter/submillimeter Array, ALMA, combines a large collecting area, very sensitive receivers and a location
on a high dry site. ALMA’s sensitivity for continuum measurements is increased with the added feature of an 8 GHz instantaneous
bandwidth. Taken together, these four factors provide unparalleled sensitivity in the millimeter/submillimeter wavelength
range. With its great sensitivity and angular resolution, ALMA will transform our view of mm/sub-mm astronomy. 相似文献
4.
The submillimeter (submm) extragalactic background light (EBL) traces the integrated star formation history throughout the
cosmic time. Deep blank-field 850 μm and 1.4 GHz surveys and optical follow-up have been only able to determine the redshift
of ∼20% of the submm EBL. The majority (80%) of the submm EBL is still below the confusion and sensitivity limits of current
submm and radio instruments. We break through these limits with stacking analyses on our deep 850 μm image in the GOODS-N
and find that the submm EBL mostly comes from galaxies at redshifts around 1.0. This redshift is much lower than the redshift
of z=2–3 previously implied from radio identified submm sources. This result significantly decreases the number of high redshift
galaxies that may be seen by ALMA. 相似文献
5.
Kazushi Sakamoto 《Astrophysics and Space Science》2008,313(1-3):245-251
Between gas dynamics and structure of galaxies is a two-way relation. On one hand, gas dynamics in a galaxy is largely determined
by the structure of the galaxy, and on the other hand, gas dynamics can gradually alter the galaxy structure through redistribution
of mass and angular momentum within the galaxy. The first half of this relation should mostly determine gas distribution and
regulate star formation in undisturbed spirals, and the second half has been suggested to cause secular evolution of spiral
galaxies—a slow mode of galaxy evolution in the absence of major mergers. Our knowledge on this relation is going to be greatly
deepened by the ALMA. Focusing on the galaxy evolution through gas dynamics, I briefly review what we know about the subject.
Then I try to look out what the ALMA can do to answer open questions in the field. It is pointed out that the ALMA will be
able to fully map all the spiral galaxies between 1 and 25 Mpc at 1″ resolution in 1000 hours. 相似文献
6.
Amy J. Lovell 《Astrophysics and Space Science》2008,313(1-3):191-196
Thermal observations of large asteroids at millimeter wavelengths have revealed high amplitude rotational lightcurves. Such
lightcurves are important constraints on thermophysical models of asteroids, and provide unique insight into the nature of
their surface and subsurface composition. A better understanding of asteroid surfaces provides insight into the composition,
physical structures, and processing history of these surviving remnants from the formation of our solar system. In addition,
detailed observations of the larger asteroids, accompanied by thermophysical models with appropriate temporal and spatial
resolution, promise to decrease uncertainties in their flux predictions. Of particular interest are the near-Earth objects,
which can be observed at large phase angles, permitting better assessment of the thermal response of their unilluminated surfaces.
The high sensitivity of ALMA will enable us to detect many small bodies in all the major groups, to obtain lightcurves for
a large sample of main-belt and near-Earth objects, to resolve the surfaces of some large objects, and to separate the emission
from primary and secondary objects in binary pairs. In addition to the science goals of asteroid studies, these bodies may
also prove useful operationally because those with known shapes and well-characterized lightcurves could be employed for flux
calibration by ALMA and other high frequency instruments. 相似文献
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