Scientific role of ACA for low-mass star-formation study     

Shigehisa Takakuwa  Daisuke Iono  Baltasar Vila-Vilaro  Tomohiko Sekiguchi  Ryohei Kawabe 《Astrophysics and Space Science》2008,313(1-3):169-173

We discuss the scientific role of the Atacama Compact Array (ACA), the Japanese contribution to the ALMA project, for low-mass star-formation study. Our recent observations of several low-mass protostellar envelopes in the submillimeter CS (J=7–6) and HCN (J=4–3) lines with the SMA and ASTE have revealed that these submillimeter emissions are more extended than ∼2000 AU and show different velocity structures from those traced by millimeter lines. These results suggest the importance of taking short-spacing informations the ACA can offer. Our comprehensive imaging simulations of these protostellar envelopes, as well as prestellar cores and debris disks, unprecedentedly demonstrate the scientific importance of ACA.  相似文献   

The effect of recent climatic trends on Urticaceae pollination in two bioclimatically different areas in the Iberian Peninsula: Malaga and Vigo     

Marta Recio  F. Javier Rodríguez-Rajo  M. Victoria Jato  M. Mar Trigo  Baltasar Cabezudo 《Climatic change》2009,97(1-2):215-228

Malaga (Mediterranean coast) and Vigo (Atlantic coast) are representative of two bioclimatically different areas belonging to the Mediterranean and the Eurosiberian region, respectively. This contribution represents a study on recent trends in the principal meteorological parameters in these areas and their influence on the phenology of Urticaceae (nettle family) atmospheric pollen, one of the main causes of pollinosis in Spain. The study covers the period 1991–2006 for Malaga and 1995–2005 for Vigo, and compares the differences in climate and phenological behaviour observed at both localities. The sampling of atmospheric pollen was performed with Hirst volumetric pollen traps. The two localities present different tendencies as far as temperature is concerned: while the mean annual temperature in the Mediterranean region has increased by 0.06°C/year, the same parameter has decreased in the Atlantic area by 0.1°C/year. This tendency is even more pronounced as far as the minimum temperatures are concerned, especially during spring in Malaga and autumn in Vigo. On the other hand, wind speed has tended to increase, periods of calm have diminished and winds blowing off the sea have increased in both places. These changes in meteorological parameters have advanced the end of the pollen season in Malaga and delayed its start in Vigo. Total annual pollen counts have decreased in Vigo, while the number of pollen-free days has increased in both areas.  相似文献   

Spectroscopy of the Extended Emission Line Region in NGC 4388     

L. Tomas-Calderon  J.A. Acosta-Pulido  B. Vila-Vilaro  I. Perez-Fournon 《Astrophysics and Space Science》1998,263(1-4):123-126

We present preliminary results of long-slit spectroscopic observations of the extended emission line region (hereafter, EELR) in NGC 4388. We detect broad emission lines in the line complexes Hα+[NII] and [SII] which can be modelled by the superposition of several narrow components. Multicomponent line profiles appear at positions very close to the ionization cone axis. There is also some correspondence with the radio emission, which suggests that there is interaction between the radio jets and the ionized gas. We do not confirm the claim of a broad Hα component (FWZI=4000 km/s) by Shields and Filippenko (1996). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献