In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements wit...In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements with theoretical stellar population synthesis models of Bruzual & Charlot. Also, we calculate the mass of these star clusters using the theoretical M/LV ratio. The results show that, these star clusters formed continuously in M33 from ~ 7 × 10<SUP>6</SUP>–10<SUP>10</SUP> years and have masses between ~ 10<SUP>3</SUP> and 2 × 10<SUP>6</SUP>M<SUB>☉</SUB>. M33 frames were observed as a part of the BATC Multicolor Survey of the sky in 13 intermediate-band filters from 3800 to 10 000?. The relation between age and mass confirms that the sample star cluster masses systematically decrease from the oldest to the youngest.展开更多
Based on the method proposed by Kong et al. and on the multi-color spectrophotometry by Ma et al., we estimate the metallicities of 16 old star clusters in the nearby spiral galaxy M33, ten of which are halo globula...Based on the method proposed by Kong et al. and on the multi-color spectrophotometry by Ma et al., we estimate the metallicities of 16 old star clusters in the nearby spiral galaxy M33, ten of which are halo globular clusters. These old clusters are all metal poor, the range of metallicity ([Fe/H]) is from-0.14 to-2.12. In general, our results are consistent with those derived by other methods, such as integrated spectra and photometry, and our study confirms the reliability of the method of Kong et al.展开更多
We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） in fields in the vicinity of M31 and M33, targeted as globular clusters（GCs） and candidates. ...We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） in fields in the vicinity of M31 and M33, targeted as globular clusters（GCs） and candidates. The targets include known GCs and candidates selected from the literature, as well as new candidates selected from the Sloan Digital Sky Survey（SDSS）. Analysis shows that 356 of them are likely GCs with various confidence levels, while the remaining ones turn out to be background galaxies and quasars, stars and H II regions in M31 or foreground Galactic stars. The 356 likely GCs include 298 bona fide GCs and 26 candidates known in the literature. Three candidates, selected from the Revised Bologna Catalog of M31 GCs and candidates（RBC） and one possible cluster from Johnson et al., are confirmed to be bona fide clusters. We search for new GCs in the halo of the M31 among the new candidates selected from the SDSS photometry. Based on radial velocities yielded by LAMOST spectra and visual examination of the SDSS images, we find 28 objects, 5bona fide and 23 likely GCs. Among the five bona fide GCs, three have been recently discovered independently by others, and the remaining 25 are our new identifications,including two bona fide ones. The newly identified objects fall at projected distances ranging from 13 to 265 kpc from M31. Of the two newly discovered bona fide GCs,one is located near M33, probably a GC belonging to M33. The other bona fide GC falls on the Giant Stream with a projected distance of 78 kpc from M31. Of the 23 newly identified likely GCs, one has a projected distance of about 265 kpc from M31 and could be an intergalactic cluster.展开更多
In this work, we report new quasars discovered in fields in the vicinity of the Andromeda（M31） and Triangulum（M33） galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST, also called t...In this work, we report new quasars discovered in fields in the vicinity of the Andromeda（M31） and Triangulum（M33） galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST, also called the Guo Shou Jing Telescope） during the 2013 observational season, the second year of the regular survey. In total, 1330 new quasars are discovered in an area of ～133 deg2 around M31and M33. With i magnitudes ranging from 14.79 to 20.0 and redshifts from 0.08 to4.85, the 1330 new quasars represent a significant increase in the number of identified quasars in fields in the vicinity of M31 and M33. Up to now, there have been a total of 1870 quasars discovered by LAMOST in this area. The much enlarged sample of known quasars in this area can potentially be utilized to construct a precise astrometric reference frame for the measurement of minute proper motions of M31, M33 and their associated substructures, which are vital for understanding the formation and evolution of M31, M33 and the Local Group of galaxies. Moreover, in the sample,there are a total of 45, 98 and 225 quasars with i magnitudes brighter than 17.0, 17.5and 18.0 respectively. In the aforementioned brightness bins, 15, 35 and 84 quasars are reported here for the first time, and 6, 21 and 81 are reported in our pervious work. In addition, 0, 1 and 6 are from the Sloan Digital Sky Survey and 24, 41 and 54 are from the NED database. These bright quasars provide an invaluable sample to study the kinematics and chemistry of the interstellar/intergalactic medium of the Local Group.展开更多
We present accurate positions and multi-color photometry for 41 star clusters detected by Melnick & D'odorico in the nearby spiral galaxy M33 as a part of the BATC Color Survey of the sky in 13 intermediate-ba...We present accurate positions and multi-color photometry for 41 star clusters detected by Melnick & D'odorico in the nearby spiral galaxy M33 as a part of the BATC Color Survey of the sky in 13 intermediate-band filters from 3800 to 10 000 A. The coordinates of the clusters are found from the HST Guide Star Catalog. By aperture photometry, we obtain the spectral energy distributions of the clusters. Using the relations between the BATC intermediate-band system and UBVRI broadband system, we derive their V magnitudes and B - V colors and find that most of them are blue, which is consistent with previous findings.展开更多
We present a catalogue of 3305 Hα emission-line point sources observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) in the vicinity fields of M31 and M33 during September 2011 and Januar...We present a catalogue of 3305 Hα emission-line point sources observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) in the vicinity fields of M31 and M33 during September 2011 and January 2016.The catalogue contains 1487 emission-line stars,532 emission-line nebulae including 377 likely planetary nebulae(PNe),83 H Ⅱ region candidates and 20 possible supernova remnants(SNRs) and 1286 unknown objects.Among them,24 PN candidates,19 H Ⅱ region candidates,10 SNR candidates and one symbiotic star candidate are new discoveries.Radial velocities and fluxes estimated from the Hα line and those quantities of seven other major emission lines including Hβ,[O Ⅲ] A4959,[O Ⅲ] A5007,[N Ⅱ] A6548,[N Ⅱ] A6583,[S Ⅱ] A6717 and [S Ⅱ] A6731 lines of all the catalogued sources yielded from the LAMOST spectra are also presented in our catalogue.Our catalogue is an ideal starting point to study the chemistry properties and kinematics of M 31 and M 33.展开更多
In this work, predictions of the spectral energy distribution from populations of single and binary stars are incorporated into a galactic chemical and color evolution model to explore the significance of the effects ...In this work, predictions of the spectral energy distribution from populations of single and binary stars are incorporated into a galactic chemical and color evolution model to explore the significance of the effects of the binary interactions on the color evolution of M33. We first constructed a model without binary interactions, and the model is able to reproduce most of the available observational constraints on the distribution of stellar parameters. We then run simulations with the same set of model parameters but with binary interactions considered. By comparing the results for the populations with and without binary interactions, we find that the inclusion of binary interactions makes the surface brightness greater (~0.1 mag arcsec 2) in FUV-band but smaller (~0.7 mag arcsec 2) in K-band, while it results in the FUV K color bluer (~0.8 mag). To reproduce the observations, a model that considers the binary interactions should make more gas fall onto the disk in the early time of the galaxy evolution, or increase the total stellar mass, or both.展开更多
作为MCU市场的后来者,要利用自己的原有优势跨界进入。例如Dialog半导体公司擅长电源管理、模拟芯片和蓝牙芯片等,不久前,该公司重磅推出了32位产品——蓝牙低功耗无线多核MCU。公司低功耗连接业务部总监Mark de Clercq接受了电子产品...作为MCU市场的后来者,要利用自己的原有优势跨界进入。例如Dialog半导体公司擅长电源管理、模拟芯片和蓝牙芯片等,不久前,该公司重磅推出了32位产品——蓝牙低功耗无线多核MCU。公司低功耗连接业务部总监Mark de Clercq接受了电子产品世界等媒体的采访。展开更多
基金Supported by the National Natural Science Foundation of China
文摘In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements with theoretical stellar population synthesis models of Bruzual & Charlot. Also, we calculate the mass of these star clusters using the theoretical M/LV ratio. The results show that, these star clusters formed continuously in M33 from ~ 7 × 10<SUP>6</SUP>–10<SUP>10</SUP> years and have masses between ~ 10<SUP>3</SUP> and 2 × 10<SUP>6</SUP>M<SUB>☉</SUB>. M33 frames were observed as a part of the BATC Multicolor Survey of the sky in 13 intermediate-band filters from 3800 to 10 000?. The relation between age and mass confirms that the sample star cluster masses systematically decrease from the oldest to the youngest.
基金the Chinese Acadeinv of Sciences,the Chinese National Naturnal Science Foundation and the Ministry of sciences and technology of ChinaThe project is also supported in part by the National Science Foundation(grant IXT 93-01805)by Arizona State University,the University of Arizona and Western Connecticut State University
文摘Based on the method proposed by Kong et al. and on the multi-color spectrophotometry by Ma et al., we estimate the metallicities of 16 old star clusters in the nearby spiral galaxy M33, ten of which are halo globular clusters. These old clusters are all metal poor, the range of metallicity ([Fe/H]) is from-0.14 to-2.12. In general, our results are consistent with those derived by other methods, such as integrated spectra and photometry, and our study confirms the reliability of the method of Kong et al.
基金supported by the National Basic Research Program of China (973 Program, 2014CB845700)the China Postdoctoral Science Foundation (2014M560843)
文摘We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） in fields in the vicinity of M31 and M33, targeted as globular clusters（GCs） and candidates. The targets include known GCs and candidates selected from the literature, as well as new candidates selected from the Sloan Digital Sky Survey（SDSS）. Analysis shows that 356 of them are likely GCs with various confidence levels, while the remaining ones turn out to be background galaxies and quasars, stars and H II regions in M31 or foreground Galactic stars. The 356 likely GCs include 298 bona fide GCs and 26 candidates known in the literature. Three candidates, selected from the Revised Bologna Catalog of M31 GCs and candidates（RBC） and one possible cluster from Johnson et al., are confirmed to be bona fide clusters. We search for new GCs in the halo of the M31 among the new candidates selected from the SDSS photometry. Based on radial velocities yielded by LAMOST spectra and visual examination of the SDSS images, we find 28 objects, 5bona fide and 23 likely GCs. Among the five bona fide GCs, three have been recently discovered independently by others, and the remaining 25 are our new identifications,including two bona fide ones. The newly identified objects fall at projected distances ranging from 13 to 265 kpc from M31. Of the two newly discovered bona fide GCs,one is located near M33, probably a GC belonging to M33. The other bona fide GC falls on the Giant Stream with a projected distance of 78 kpc from M31. Of the 23 newly identified likely GCs, one has a projected distance of about 265 kpc from M31 and could be an intergalactic cluster.
基金supported by the National Key Basic Research Program of China (2014CB845705)the National Natural Science Foundation of China (NSFC, Grant No. 11403038)
文摘In this work, we report new quasars discovered in fields in the vicinity of the Andromeda（M31） and Triangulum（M33） galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST, also called the Guo Shou Jing Telescope） during the 2013 observational season, the second year of the regular survey. In total, 1330 new quasars are discovered in an area of ～133 deg2 around M31and M33. With i magnitudes ranging from 14.79 to 20.0 and redshifts from 0.08 to4.85, the 1330 new quasars represent a significant increase in the number of identified quasars in fields in the vicinity of M31 and M33. Up to now, there have been a total of 1870 quasars discovered by LAMOST in this area. The much enlarged sample of known quasars in this area can potentially be utilized to construct a precise astrometric reference frame for the measurement of minute proper motions of M31, M33 and their associated substructures, which are vital for understanding the formation and evolution of M31, M33 and the Local Group of galaxies. Moreover, in the sample,there are a total of 45, 98 and 225 quasars with i magnitudes brighter than 17.0, 17.5and 18.0 respectively. In the aforementioned brightness bins, 15, 35 and 84 quasars are reported here for the first time, and 6, 21 and 81 are reported in our pervious work. In addition, 0, 1 and 6 are from the Sloan Digital Sky Survey and 24, 41 and 54 are from the NED database. These bright quasars provide an invaluable sample to study the kinematics and chemistry of the interstellar/intergalactic medium of the Local Group.
基金the Chinese Academy of Sciencesthe,the Chinese National Natural Science Foundation and the Ministry of Sciences and Technology of ChinaThe project is also supported partly by the National Science Foundation (grant INT 93-01805)+1 种基金 by Arizona State Universitythe University of Arizona and Western ConetiutState Universitv.
文摘We present accurate positions and multi-color photometry for 41 star clusters detected by Melnick & D'odorico in the nearby spiral galaxy M33 as a part of the BATC Color Survey of the sky in 13 intermediate-band filters from 3800 to 10 000 A. The coordinates of the clusters are found from the HST Guide Star Catalog. By aperture photometry, we obtain the spectral energy distributions of the clusters. Using the relations between the BATC intermediate-band system and UBVRI broadband system, we derive their V magnitudes and B - V colors and find that most of them are blue, which is consistent with previous findings.
基金funded by the National Natural Science Foundation of China (NSFC, Grant Nos.11080922,11803029,11973001,U1531244, 11833006 and U1731308)the National Key R&D Program of China (No.2019YFA0405500)。
文摘We present a catalogue of 3305 Hα emission-line point sources observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) in the vicinity fields of M31 and M33 during September 2011 and January 2016.The catalogue contains 1487 emission-line stars,532 emission-line nebulae including 377 likely planetary nebulae(PNe),83 H Ⅱ region candidates and 20 possible supernova remnants(SNRs) and 1286 unknown objects.Among them,24 PN candidates,19 H Ⅱ region candidates,10 SNR candidates and one symbiotic star candidate are new discoveries.Radial velocities and fluxes estimated from the Hα line and those quantities of seven other major emission lines including Hβ,[O Ⅲ] A4959,[O Ⅲ] A5007,[N Ⅱ] A6548,[N Ⅱ] A6583,[S Ⅱ] A6717 and [S Ⅱ] A6731 lines of all the catalogued sources yielded from the LAMOST spectra are also presented in our catalogue.Our catalogue is an ideal starting point to study the chemistry properties and kinematics of M 31 and M 33.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11033008 and 10821061)the Chinese Academy of Sciences (Grant No. KJCX2-YW-T24)
文摘In this work, predictions of the spectral energy distribution from populations of single and binary stars are incorporated into a galactic chemical and color evolution model to explore the significance of the effects of the binary interactions on the color evolution of M33. We first constructed a model without binary interactions, and the model is able to reproduce most of the available observational constraints on the distribution of stellar parameters. We then run simulations with the same set of model parameters but with binary interactions considered. By comparing the results for the populations with and without binary interactions, we find that the inclusion of binary interactions makes the surface brightness greater (~0.1 mag arcsec 2) in FUV-band but smaller (~0.7 mag arcsec 2) in K-band, while it results in the FUV K color bluer (~0.8 mag). To reproduce the observations, a model that considers the binary interactions should make more gas fall onto the disk in the early time of the galaxy evolution, or increase the total stellar mass, or both.
