2MASS(Two Micron All Sky Survey)以相当高的内部一致性和精确度在近红外波段对整个天空进行了巡天观测,并通过数据处理把原始数据转变为对天文学有用的图像、星等和位置的列表。较详细介绍了2MASS的科学意义、巡天成果、数据特征以及...2MASS(Two Micron All Sky Survey)以相当高的内部一致性和精确度在近红外波段对整个天空进行了巡天观测,并通过数据处理把原始数据转变为对天文学有用的图像、星等和位置的列表。较详细介绍了2MASS的科学意义、巡天成果、数据特征以及利用2MASS观测数据所开展的部分工作。展开更多
IRAS low-resolution spectra are presented for 36 HAEBE stars. It is found that silicate dust in amorphous or glassy form is common material in the circumstellar disks or/and shells of HAEBE stars. It is also found tha...IRAS low-resolution spectra are presented for 36 HAEBE stars. It is found that silicate dust in amorphous or glassy form is common material in the circumstellar disks or/and shells of HAEBE stars. It is also found that the PAH feature is often appeared as well.展开更多
The high-resolution absorption spectra of the （2,0）,（3,1）,and （8,5） bands of the A^2Π^u-X^2∑g^＋ system of ^15N2^＋ have been recorded by using velocity modulation spectroscopy technique in the near infrared r...The high-resolution absorption spectra of the （2,0）,（3,1）,and （8,5） bands of the A^2Π^u-X^2∑g^＋ system of ^15N2^＋ have been recorded by using velocity modulation spectroscopy technique in the near infrared region.The rotational constants of the X^2∑g^＋ and A^2Πu states of ^15N2^＋ were derived from the spectroscopic data.The isotope shifts of these bands of the A^2Πu-X^2∑g^＋ system of ^14N2^＋ and ^15N2^＋ were also analyzed and discussed.展开更多
We performed a multiwavelength study towards the infrared dark cloud （IRDC） G31.23＋0.05 with new CO observations from Purple Mountain Observatory and archival data （the GLIMPSE, MIPSGAL, HERSCHEL, ATLASGAL, BGPS a...We performed a multiwavelength study towards the infrared dark cloud （IRDC） G31.23＋0.05 with new CO observations from Purple Mountain Observatory and archival data （the GLIMPSE, MIPSGAL, HERSCHEL, ATLASGAL, BGPS and NVSS surveys）. From these observations, we iden- tified three IRDCs with systemic velocities of 108.36 ± 0.06 （cloud A）, 104.22 ± 0.11 （cloud B） and 75.73 ± 0.07 km s-1 （cloud C） in the line of sight towards IRDC G31.23. Analyses of the molecular and dust emission suggest that cloud A is a filamentary structure containing a young stellar object; clouds B and C both include a starless core. Clouds A and B are gravitationally bound and have a chance to form stars. In addition, the velocity information and the position-velocity diagram suggest that clouds A and B are adjacent in space and provide a clue hinting at a possible cloud-cloud collision. Additionally, the distribution of dust temperature shows a temperature bubble. The compact core in cloud A is associated with an UCHII region, an IRAS source, H20 masers, CH3OH masers and OH masers, suggesting that massive star formation is active there. We estimate the age of the HII region to be （0.03-0.09）Myr, indicating that the star inside is young.展开更多
We present a study of the origin of infrared (IR) emission in the opticallynormal, infrared luminous galaxy NGC 4418. By decomposing the stellar absorption features andcontinua in the range of 3600-8000 A from the Slo...We present a study of the origin of infrared (IR) emission in the opticallynormal, infrared luminous galaxy NGC 4418. By decomposing the stellar absorption features andcontinua in the range of 3600-8000 A from the Sloan Digital Sky Survey into a set of simple stellarpopulations, we derive the stellar properties for the nuclear region of NGC 4418. We compare theobserved infrared luminosity with the one derived from the starburst model, and find thatstar-forming activity contributes only 7% to the total IR emission, that as the IR emission regionis spatially very compact, the most possible source for the greater part of the IR emission is adeeply embedded AGN, though an AGN component is found to be unnecessary for fitting the opticalspectrum.展开更多
We observed the nearby galaxy M31 in the 〔C II〕158 μm emission line. An extended component was detected over the central 1 5 kpc region with a line-to-continuum ratio of 〔C II〕/〔40-120μm〕6×10 -3 . This ra...We observed the nearby galaxy M31 in the 〔C II〕158 μm emission line. An extended component was detected over the central 1 5 kpc region with a line-to-continuum ratio of 〔C II〕/〔40-120μm〕6×10 -3 . This ratio is 3 times larger than that of the Galactic counterpart and is comparable to that in the general Galactic Plane. We expect that the difference between the two central regions are due to different gas densities; the self-shielding of CO molecules decreases the C + abundance at the higher density in the Galactic case.展开更多
文摘IRAS low-resolution spectra are presented for 36 HAEBE stars. It is found that silicate dust in amorphous or glassy form is common material in the circumstellar disks or/and shells of HAEBE stars. It is also found that the PAH feature is often appeared as well.
基金supported by the National Natural Science Foundation of China(Grant No.11674096)
文摘The high-resolution absorption spectra of the （2,0）,（3,1）,and （8,5） bands of the A^2Π^u-X^2∑g^＋ system of ^15N2^＋ have been recorded by using velocity modulation spectroscopy technique in the near infrared region.The rotational constants of the X^2∑g^＋ and A^2Πu states of ^15N2^＋ were derived from the spectroscopic data.The isotope shifts of these bands of the A^2Πu-X^2∑g^＋ system of ^14N2^＋ and ^15N2^＋ were also analyzed and discussed.
基金supported by the National Key Basic Research Program of China(No.2015CB857100)the National Natural Science Foundation of China(Grant Nos.11403052,11363004 and 11403042)
文摘We performed a multiwavelength study towards the infrared dark cloud （IRDC） G31.23＋0.05 with new CO observations from Purple Mountain Observatory and archival data （the GLIMPSE, MIPSGAL, HERSCHEL, ATLASGAL, BGPS and NVSS surveys）. From these observations, we iden- tified three IRDCs with systemic velocities of 108.36 ± 0.06 （cloud A）, 104.22 ± 0.11 （cloud B） and 75.73 ± 0.07 km s-1 （cloud C） in the line of sight towards IRDC G31.23. Analyses of the molecular and dust emission suggest that cloud A is a filamentary structure containing a young stellar object; clouds B and C both include a starless core. Clouds A and B are gravitationally bound and have a chance to form stars. In addition, the velocity information and the position-velocity diagram suggest that clouds A and B are adjacent in space and provide a clue hinting at a possible cloud-cloud collision. Additionally, the distribution of dust temperature shows a temperature bubble. The compact core in cloud A is associated with an UCHII region, an IRAS source, H20 masers, CH3OH masers and OH masers, suggesting that massive star formation is active there. We estimate the age of the HII region to be （0.03-0.09）Myr, indicating that the star inside is young.
基金the National Natural Science Foundation of China.
文摘We present a study of the origin of infrared (IR) emission in the opticallynormal, infrared luminous galaxy NGC 4418. By decomposing the stellar absorption features andcontinua in the range of 3600-8000 A from the Sloan Digital Sky Survey into a set of simple stellarpopulations, we derive the stellar properties for the nuclear region of NGC 4418. We compare theobserved infrared luminosity with the one derived from the starburst model, and find thatstar-forming activity contributes only 7% to the total IR emission, that as the IR emission regionis spatially very compact, the most possible source for the greater part of the IR emission is adeeply embedded AGN, though an AGN component is found to be unnecessary for fitting the opticalspectrum.
文摘We observed the nearby galaxy M31 in the 〔C II〕158 μm emission line. An extended component was detected over the central 1 5 kpc region with a line-to-continuum ratio of 〔C II〕/〔40-120μm〕6×10 -3 . This ratio is 3 times larger than that of the Galactic counterpart and is comparable to that in the general Galactic Plane. We expect that the difference between the two central regions are due to different gas densities; the self-shielding of CO molecules decreases the C + abundance at the higher density in the Galactic case.
