The observations of the Aquila Rift cloud complex at 23.708 and 115.271 GHz made using the Nanshan 26 m radio telescope and the 13.7 m millimeter-wavelength telescope are presented.We find that the CO(1-0)gas distribu...The observations of the Aquila Rift cloud complex at 23.708 and 115.271 GHz made using the Nanshan 26 m radio telescope and the 13.7 m millimeter-wavelength telescope are presented.We find that the CO(1-0)gas distribution is similar to the NH_(3)gas distribution in the Aquila Rift cloud complex.In some diffusion regions characterized by CO,we identified several dense clumps based on the distribution of detected ammonia molecular emission.Through the comparison of spectral line parameters for NH_(3),^(13)CO,and C^(18)O,our study reveals that the line center velocities of the NH_(3),^(13)CO,and C^(18)O lines are comparable and positively correlated,indicating that they originate from the same emission region.No significant correlation was identified for other parameters,including integrated intensity,line widths,main beam brightness temperature,as well as the column densities of NH_(3),^(13)CO,and C^(18)O.The absolute difference in line-center velocities between the^(13)CO and NH_(3)lines is less than both the average line width of NH_(3)and that of^(13)CO.This suggests that there are no significant movements of NH_(3)clumps in relation to their envelopes.The velocity deviation is likely due to turbulent activity within the clumps.展开更多
We present an analysis of 288 young stellar objects(YSOs)in the Perseus molecular cloud that have well defined g and r-band lightcurves from the Zwicky Transient Facility.Of the 288 YSOs,238 sources(83%of our working ...We present an analysis of 288 young stellar objects(YSOs)in the Perseus molecular cloud that have well defined g and r-band lightcurves from the Zwicky Transient Facility.Of the 288 YSOs,238 sources(83%of our working sample)are identified as variables based on the normalized peak-to-peak variability metric,with variability fraction of 92%for stars with disks and 77%for the diskless populations.These variables are classified into different categories using the quasiperiodicity(Q)and flux asymmetry(M)metrics.Fifty-three variables are classified as strictly periodic objects that are well phased and can be attributed to spot modulated stellar rotation.We also identify 22 bursters and 25 dippers,which can be attributed to accretion burst and variable extinction,respectively.YSOs with disks tend to have asymmetric and non-repeatable lightcurves,while the YSOs without disks tend to have(quasi)periodic lightcurves.The periodic variables have the steepest change in g versus g-r,while bursters have much flatter changes than dippers in g versus g-r.Periodic and quasiperiodic variables display the lowest variability amplitude.Simple models suggest that the variability amplitudes of periodic variables correspond to changes of the spot coverage of 30%-40%,burster variables are attributed to accretion luminosity changes in the range of L_(acc)/L_(*)=0.1-0.3,and dippers are due to variable extinction with A_(V)changes in the range of 0.5-1.3 mag.展开更多
基金supported by the National Key R&D Programs of China(Nos.2023YFA1608002,and 2022YFA1603103)the regional Collaborative Innovation Project of Xinjiang Uyghur Autonomous Region(No.2022E01050)+6 种基金the Tianshan Talent Program of Xinjiang Uyghur Autonomous Region(No.2022TSYCLJ0005)the Tianchi Talent Project of Xinjiang Uyghur Autonomous Region,the Natural Science Foundation of Xinjiang Uyghur Autonomous Region(No.2022D01E06)the Chinese Academy of Sciences(CAS)“Light of West China”Program(Nos.xbzgzdsys-202212,2020-XBQNXZ-017,and 2021-XBQNXZ-028)the National Natural Science Foundation of China(Nos.12173075,11973076,and 12103082)the Xinjiang Key Laboratory of Radio Astrophysics(No.2022D04033)the Chinese Academy of Sciences President's International Fellowship Initiative(Nos.2022VMA0019,and 2023VMA0030)the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan(No.AP13067768)。
文摘The observations of the Aquila Rift cloud complex at 23.708 and 115.271 GHz made using the Nanshan 26 m radio telescope and the 13.7 m millimeter-wavelength telescope are presented.We find that the CO(1-0)gas distribution is similar to the NH_(3)gas distribution in the Aquila Rift cloud complex.In some diffusion regions characterized by CO,we identified several dense clumps based on the distribution of detected ammonia molecular emission.Through the comparison of spectral line parameters for NH_(3),^(13)CO,and C^(18)O,our study reveals that the line center velocities of the NH_(3),^(13)CO,and C^(18)O lines are comparable and positively correlated,indicating that they originate from the same emission region.No significant correlation was identified for other parameters,including integrated intensity,line widths,main beam brightness temperature,as well as the column densities of NH_(3),^(13)CO,and C^(18)O.The absolute difference in line-center velocities between the^(13)CO and NH_(3)lines is less than both the average line width of NH_(3)and that of^(13)CO.This suggests that there are no significant movements of NH_(3)clumps in relation to their envelopes.The velocity deviation is likely due to turbulent activity within the clumps.
基金the support of the CAS International Cooperation Program(Grant No.114332KYSB20190009)the National Natural Science Foundation of China(NSFC)Grant No.12033004+2 种基金supported by grant 12173003 from the NSFCFunding for the project has been provided by the National Development and Reform Commissionsupported by the National Science Foundation under grant Nos.AST1440341 and AST-2034437。
文摘We present an analysis of 288 young stellar objects(YSOs)in the Perseus molecular cloud that have well defined g and r-band lightcurves from the Zwicky Transient Facility.Of the 288 YSOs,238 sources(83%of our working sample)are identified as variables based on the normalized peak-to-peak variability metric,with variability fraction of 92%for stars with disks and 77%for the diskless populations.These variables are classified into different categories using the quasiperiodicity(Q)and flux asymmetry(M)metrics.Fifty-three variables are classified as strictly periodic objects that are well phased and can be attributed to spot modulated stellar rotation.We also identify 22 bursters and 25 dippers,which can be attributed to accretion burst and variable extinction,respectively.YSOs with disks tend to have asymmetric and non-repeatable lightcurves,while the YSOs without disks tend to have(quasi)periodic lightcurves.The periodic variables have the steepest change in g versus g-r,while bursters have much flatter changes than dippers in g versus g-r.Periodic and quasiperiodic variables display the lowest variability amplitude.Simple models suggest that the variability amplitudes of periodic variables correspond to changes of the spot coverage of 30%-40%,burster variables are attributed to accretion luminosity changes in the range of L_(acc)/L_(*)=0.1-0.3,and dippers are due to variable extinction with A_(V)changes in the range of 0.5-1.3 mag.
