We demonstrate the power of Gibbs point process models from the spatial statistics literature when applied to studies of resolved galaxies. We conduct a rigorous analysis of the spatial distributions of objects in the star formation complexes of M33, including giant molecular clouds (GMCs) and young stellar cluster candidates (YSCCs). We choose a hierarchical model structure from GMCs to YSCCs based on the natural formation hierarchy between them. This approach circumvents the limitations of the empirical two-point correlation function analysis by naturally accounting for the inhomogeneity present in the distribution of YSCCs. We also investigate the effects of GMCs' properties on their spatial distributions. We confirm that the distribution of GMCs and YSCCs are highly correlated. We found that the spatial distributions of YSCCs reaches a peak of clustering pattern at ~250 pc scale compared to a Poisson process. This clustering mainly occurs in regions where the galactocentric distance >~4.5 kpc. Furthermore, the galactocentric distance of GMCs and their mass have strong positive effects on the correlation strength between GMCs and YSCCs. We outline some possible implications of these findings for our understanding of the cluster formation process.
{"title":"Gibbs point process model for young star clusters in M33","authors":"Dayi Li, P. Barmby","doi":"10.1093/mnras/staa3908","DOIUrl":"https://doi.org/10.1093/mnras/staa3908","url":null,"abstract":"We demonstrate the power of Gibbs point process models from the spatial statistics literature when applied to studies of resolved galaxies. We conduct a rigorous analysis of the spatial distributions of objects in the star formation complexes of M33, including giant molecular clouds (GMCs) and young stellar cluster candidates (YSCCs). We choose a hierarchical model structure from GMCs to YSCCs based on the natural formation hierarchy between them. This approach circumvents the limitations of the empirical two-point correlation function analysis by naturally accounting for the inhomogeneity present in the distribution of YSCCs. We also investigate the effects of GMCs' properties on their spatial distributions. We confirm that the distribution of GMCs and YSCCs are highly correlated. We found that the spatial distributions of YSCCs reaches a peak of clustering pattern at ~250 pc scale compared to a Poisson process. This clustering mainly occurs in regions where the galactocentric distance >~4.5 kpc. Furthermore, the galactocentric distance of GMCs and their mass have strong positive effects on the correlation strength between GMCs and YSCCs. We outline some possible implications of these findings for our understanding of the cluster formation process.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84986868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal instability (TI) plays a crucial role in the formation of multiphase structures and their dynamics in the Interstellar Medium (ISM) and is a leading theory for cold cloud creation in various astrophysical environments. In this paper we investigate thermal instability under the influence of various initial conditions and physical processes. We experiment with Gaussian random field (GRF) density perturbations of different initial power spectra. We also enroll thermal conduction and physical viscosity in isotropic hydrodynamic and anisotropic magnetohydrodynamic (MHD) simulations. We find that the initial GRF spectral index $alpha$ has a dramatic impact on the pure hydrodynamic development of thermal instability, influencing the size, number and motions of clouds. Cloud fragmentation happens due to two mechanisms: tearing and contraction rebound. In the runs with isotropic conduction and viscosity, the structures and dynamics of the clouds are dominated by evaporation and condensation flows in the non-linear regime, and the flow speed is regulated by viscosity. Cloud disruptions happen as a result of the Darrieus--Landau instability (DLI). Although at very late times, all individual clouds merge into one cold structure in all hydrodynamic runs. In the MHD case, the cloud structure is determined by both the initial perturbations and the initial magnetic field strength. In high $beta$ runs, anisotropic conduction causes dense filaments to align with the local magnetic fields and the field direction can become reoriented. Strong magnetic fields suppress cross-field contraction and cold filaments can form along or perpendicular to the initial fields.
{"title":"Thermal instability and multiphase gas in the simulated interstellar medium with conduction, viscosity, and magnetic fields","authors":"R. Jennings, Yuan Li","doi":"10.1093/mnras/stab1607","DOIUrl":"https://doi.org/10.1093/mnras/stab1607","url":null,"abstract":"Thermal instability (TI) plays a crucial role in the formation of multiphase structures and their dynamics in the Interstellar Medium (ISM) and is a leading theory for cold cloud creation in various astrophysical environments. In this paper we investigate thermal instability under the influence of various initial conditions and physical processes. We experiment with Gaussian random field (GRF) density perturbations of different initial power spectra. We also enroll thermal conduction and physical viscosity in isotropic hydrodynamic and anisotropic magnetohydrodynamic (MHD) simulations. We find that the initial GRF spectral index $alpha$ has a dramatic impact on the pure hydrodynamic development of thermal instability, influencing the size, number and motions of clouds. Cloud fragmentation happens due to two mechanisms: tearing and contraction rebound. In the runs with isotropic conduction and viscosity, the structures and dynamics of the clouds are dominated by evaporation and condensation flows in the non-linear regime, and the flow speed is regulated by viscosity. Cloud disruptions happen as a result of the Darrieus--Landau instability (DLI). Although at very late times, all individual clouds merge into one cold structure in all hydrodynamic runs. In the MHD case, the cloud structure is determined by both the initial perturbations and the initial magnetic field strength. In high $beta$ runs, anisotropic conduction causes dense filaments to align with the local magnetic fields and the field direction can become reoriented. Strong magnetic fields suppress cross-field contraction and cold filaments can form along or perpendicular to the initial fields.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79677779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Schroetter, N. Bouch'e, J. Zabl, H. Rahmani, M. Wendt, S. Muzahid, T. Contini, J. Schaye, K. Schmidt, L. Wisotzki
Using the MEGAFLOW survey, which consists of a combination of MUSE and UVES observations of 22 quasar fields selected to contain strong MgII absorbers, we measure covering fractions of CIV and MgII as a function of impact parameter $b$ using a novel Bayesian logistic regression method on unbinned data, appropriate for small samples. In the MUSE data, we found 215 z=1$-$1.5 [OII] emitters with fluxes$>$10^{-17}erg s-1 cm-2 and within 250 kpc of quasar sight-lines. Over this redshift path z=1$-$1.5, we have 19 (32) CIV (MgII) absorption systems with rest-frame equivalent width (REW) Wr$>$0.05{AA} associated with at least one [OII] emitter. The covering fractions of CIV (MgII) absorbers with mean Wr$approx$0.7{AA} (1.0{AA}), exceeds 50% within 30 (45) kpc, with a mild redshift evolution, in agreement with larger studies. For absorption systems that have CIV but not MgII, we find in 80% of the cases no [OII] counterpart. This may indicate that the CIV, in these cases, come from the intergalactic medium (IGM), i.e. beyond 250 kpc, or that it is associated with lower-mass or quiescent galaxies.
{"title":"MusE GAs FLOw and Wind (MEGAFLOW) VI. A study of C iv and Mg ii absorbing gas surrounding [O ii] emitting galaxies","authors":"I. Schroetter, N. Bouch'e, J. Zabl, H. Rahmani, M. Wendt, S. Muzahid, T. Contini, J. Schaye, K. Schmidt, L. Wisotzki","doi":"10.1093/mnras/stab1447","DOIUrl":"https://doi.org/10.1093/mnras/stab1447","url":null,"abstract":"Using the MEGAFLOW survey, which consists of a combination of MUSE and UVES observations of 22 quasar fields selected to contain strong MgII absorbers, we measure covering fractions of CIV and MgII as a function of impact parameter $b$ using a novel Bayesian logistic regression method on unbinned data, appropriate for small samples. In the MUSE data, we found 215 z=1$-$1.5 [OII] emitters with fluxes$>$10^{-17}erg s-1 cm-2 and within 250 kpc of quasar sight-lines. Over this redshift path z=1$-$1.5, we have 19 (32) CIV (MgII) absorption systems with rest-frame equivalent width (REW) Wr$>$0.05{AA} associated with at least one [OII] emitter. The covering fractions of CIV (MgII) absorbers with mean Wr$approx$0.7{AA} (1.0{AA}), exceeds 50% within 30 (45) kpc, with a mild redshift evolution, in agreement with larger studies. For absorption systems that have CIV but not MgII, we find in 80% of the cases no [OII] counterpart. This may indicate that the CIV, in these cases, come from the intergalactic medium (IGM), i.e. beyond 250 kpc, or that it is associated with lower-mass or quiescent galaxies.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85986092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-09DOI: 10.1103/PHYSREVD.103.024028
H. Desmond, Jeremy Sakstein, B. Jain
We perform a novel test of General Relativity by measuring the gravitational constant in the Large Magellanic Cloud (LMC). The LMC contains six well-studied Cepheid variable stars in detached eclipsing binaries. Radial velocity and photometric observations enable a complete orbital solution, and precise measurements of the Cepheids' periods permit detailed stellar modelling. Both are sensitive to the strength of gravity, the former via Kepler's third law and the latter through the gravitational free-fall time. We jointly fit the observables for stellar parameters and the gravitational constant. Performing a full Markov Chain Monte Carlo analysis of the parameter space including all relevant nuisance parameters, we constrain the gravitational constant in the Large Magellanic Cloud relative to the Solar System to be $G_text{LMC}/G_text{SS} = 0.93^{+0.05}_{-0.04}$. We discuss the implications of this 5% measurement of Newton's constant in another galaxy for dark energy and modified gravity theories. This result excludes one Cepheid, CEP-1812, which is an outlier and needs further study: it is either a highly unusual system to which our model does not apply, or it prefers $G_text{LMC}
我们通过测量大麦哲伦星云(LMC)的引力常数，对广义相对论进行了新的检验。LMC包含六颗被充分研究过的造父变星，它们是分离的食双星。视向速度和光度观测可以得到完整的轨道解，对造父变星周期的精确测量可以建立详细的恒星模型。两者都对重力强度敏感，前者通过开普勒第三定律，后者通过重力自由落体时间。我们共同拟合了恒星参数和引力常数的观测值。对包含所有相关干扰参数的参数空间进行完整的马尔可夫链蒙特卡罗分析，我们约束大麦哲伦星云相对于太阳系的引力常数为$G_text{LMC}/G_text{SS} = 0.93^{+0.05}_{-0.04}$。我们讨论这5条的含义% measurement of Newton's constant in another galaxy for dark energy and modified gravity theories. This result excludes one Cepheid, CEP-1812, which is an outlier and needs further study: it is either a highly unusual system to which our model does not apply, or it prefers $G_text{LMC}
{"title":"Five percent measurement of the gravitational constant in the Large Magellanic Cloud","authors":"H. Desmond, Jeremy Sakstein, B. Jain","doi":"10.1103/PHYSREVD.103.024028","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.024028","url":null,"abstract":"We perform a novel test of General Relativity by measuring the gravitational constant in the Large Magellanic Cloud (LMC). The LMC contains six well-studied Cepheid variable stars in detached eclipsing binaries. Radial velocity and photometric observations enable a complete orbital solution, and precise measurements of the Cepheids' periods permit detailed stellar modelling. Both are sensitive to the strength of gravity, the former via Kepler's third law and the latter through the gravitational free-fall time. We jointly fit the observables for stellar parameters and the gravitational constant. Performing a full Markov Chain Monte Carlo analysis of the parameter space including all relevant nuisance parameters, we constrain the gravitational constant in the Large Magellanic Cloud relative to the Solar System to be $G_text{LMC}/G_text{SS} = 0.93^{+0.05}_{-0.04}$. We discuss the implications of this 5% measurement of Newton's constant in another galaxy for dark energy and modified gravity theories. This result excludes one Cepheid, CEP-1812, which is an outlier and needs further study: it is either a highly unusual system to which our model does not apply, or it prefers $G_text{LMC}<G_text{SS}$ at $2.6sigma$. We also obtain new bounds on critical parameters that appear in semi-analytic descriptions of stellar processes. In particular, we measure the mixing length parameter to be $alpha=0.90^{+0.36}_{-0.26}$ (when assumed to be constant across our sample), and obtain constraints on the parameters describing turbulent dissipation and convective flux.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76386967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. B. Ngoc, P. Diep, H. Parsons, K. Pattle, Thiem C. Hoang, D. Ward-Thompson, L. Tram, C. Hull, M. Tahani, R. Furuya, P. Bastien, K. Qiu, T. Hasegawa, W. Kwon, Y. Doi, S. Lai, S. Coudé, D. Berry, T. Ching, J. Hwang, A. Soam, Jia‐Wei Wang, D. Arzoumanian, T. Bourke, D. Byun, H. Chen, Zhiwei Chen, W. Chen, Mike Chen, Jungyeon Cho, Yunhee Choi, Minho Choi, A. Chrysostomou, E. Chung, S. Dai, J. Francesco, Y. Duan, H. Duan, D. Eden, C. Eswaraiah, L. Fanciullo, J. Fiege, L. Fissel, E. Franzmann, P. Friberg, R. Friesen, G. Fuller, T. Gledhill, S. Graves, J. Greaves, M. Griffin, Q. Gu, I. Han, J. Hatchell, S. Hayashi, M. Houde, T. Inoue, S. Inutsuka, K. Iwasaki, Il-Gyo Jeong, D. Johnstone, Ji-hyun Kang, Sung-ju Kang, Miju Kang, A. Kataoka, K. Kawabata, F. Kemper, Kee-Tae Kim, Jongsoo Kim, T. Pyo, L. Qian, R. Rao, M. Rawlings, J. Rawlings, B. Retter, J. Richer, A. Rigby, S. Sadavoy, H. Saito, G. Savini, A. Scaife, M. Seta, Gwanjeong Kim, Shinyoung Kim, K. Kim, Mi-Ryang Kim, F. Kirchschlager, J. Kirk, Masato I. N.
We report the first high spatial resolution measurement of magnetic fields surrounding LkH$alpha$ 101, a part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 $mu$m is found to be mostly associated with the red-shifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of $B_{rm POS}sim 115$ $mathrm{mu}$G. The mass-to-magnetic-flux ratio in critical value units, $lambdasim0.3$, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkH$alpha$ 101 region is sub-critical and the magnetic field is strong enough to prevent gravitational collapse. The inferred $delta B/B_0sim 0.3$ implies that the large scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power-law with an index of $alpha=0.82pm0.03$, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkH$alpha$ 101) in the region. The magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques are potential of explaining such a decreasing trend.
{"title":"Observations of magnetic fields surrounding LkH$alpha$ 101 taken by the BISTRO survey with JCMT-POL-2","authors":"N. B. Ngoc, P. Diep, H. Parsons, K. Pattle, Thiem C. Hoang, D. Ward-Thompson, L. Tram, C. Hull, M. Tahani, R. Furuya, P. Bastien, K. Qiu, T. Hasegawa, W. Kwon, Y. Doi, S. Lai, S. Coudé, D. Berry, T. Ching, J. Hwang, A. Soam, Jia‐Wei Wang, D. Arzoumanian, T. Bourke, D. Byun, H. Chen, Zhiwei Chen, W. Chen, Mike Chen, Jungyeon Cho, Yunhee Choi, Minho Choi, A. Chrysostomou, E. Chung, S. Dai, J. Francesco, Y. Duan, H. Duan, D. Eden, C. Eswaraiah, L. Fanciullo, J. Fiege, L. Fissel, E. Franzmann, P. Friberg, R. Friesen, G. Fuller, T. Gledhill, S. Graves, J. Greaves, M. Griffin, Q. Gu, I. Han, J. Hatchell, S. Hayashi, M. Houde, T. Inoue, S. Inutsuka, K. Iwasaki, Il-Gyo Jeong, D. Johnstone, Ji-hyun Kang, Sung-ju Kang, Miju Kang, A. Kataoka, K. Kawabata, F. Kemper, Kee-Tae Kim, Jongsoo Kim, T. Pyo, L. Qian, R. Rao, M. Rawlings, J. Rawlings, B. Retter, J. Richer, A. Rigby, S. Sadavoy, H. Saito, G. Savini, A. Scaife, M. Seta, Gwanjeong Kim, Shinyoung Kim, K. Kim, Mi-Ryang Kim, F. Kirchschlager, J. Kirk, Masato I. N. ","doi":"10.11570/20.0011","DOIUrl":"https://doi.org/10.11570/20.0011","url":null,"abstract":"We report the first high spatial resolution measurement of magnetic fields surrounding LkH$alpha$ 101, a part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 $mu$m is found to be mostly associated with the red-shifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of $B_{rm POS}sim 115$ $mathrm{mu}$G. The mass-to-magnetic-flux ratio in critical value units, $lambdasim0.3$, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkH$alpha$ 101 region is sub-critical and the magnetic field is strong enough to prevent gravitational collapse. The inferred $delta B/B_0sim 0.3$ implies that the large scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power-law with an index of $alpha=0.82pm0.03$, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkH$alpha$ 101) in the region. The magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques are potential of explaining such a decreasing trend.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82570140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1051/0004-6361/202039270
C. Circosta, V. Mainieri, I. Lamperti, P. Padovani, M. Bischetti, C. Harrison, D. Kakkad, A. Zanella, G. Vietri, G. Lanzuisi, M. Salvato, M. Brusa, S. Carniani, C. Cicone, G. Cresci, C. Feruglio, B. Husemann, F. Mannucci, A. Marconi, M. Perna, E. Piconcelli, A. Puglisi, A. Saintonge, M. Schramm, C. Vignali, L. Zappacosta
Feedback from AGN is thought to be key in shaping the life cycle of their host galaxies by regulating star-formation activity. Therefore, to understand the impact of AGN on star formation, it is essential to trace the molecular gas out of which stars form. In this paper we present the first systematic study of the CO properties of AGN hosts at z~2 for a sample of 27 X-ray selected AGN spanning two orders of magnitude in AGN bolometric luminosity (Lbol= 10^44.7-10^46.9 erg/s) by using ALMA Band 3 observations of the CO(3-2) transition (~1" angular resolution). To search for evidence of AGN feedback on the CO properties of the host galaxies, we compared our AGN with a sample of inactive (i.e., non-AGN) galaxies from the PHIBSS survey with similar redshift, stellar masses, and SFRs. We used the same CO transition as a consistent proxy for the gas mass for the two samples in order to avoid systematics involved when assuming conversion factors. By adopting a Bayesian approach to take upper limits into account, we analyzed CO luminosities as a function of stellar masses and SFRs, as well as the ratio LCO(3-2)/M* (proxy for the gas fraction). The two samples show statistically consistent trends in the LCO(3-2)-Lfir and LCO(3-2)-M* planes. However, there are indications that AGN feature lower CO(3-2) luminosities (0.4-0.7 dex) than inactive galaxies at the 2-3sigma level when we focus on the subset of parameters where the results are better constrained and on the distribution of the mean LCO(3-2)/M*. Therefore, even by conservatively assuming the same excitation factor r31, we would find lower molecular gas masses in AGN, and assuming higher r31 would exacerbate this difference. We interpret our result as a hint of the potential effect of AGN activity (e.g., radiation and outflows), which may be able to heat, excite, dissociate, and/or deplete the gas reservoir of the host galaxies. (abridged)
{"title":"SUPER IV. CO(J=3-2) properties of active galactic nucleus hosts at cosmic noon revealed by ALMA","authors":"C. Circosta, V. Mainieri, I. Lamperti, P. Padovani, M. Bischetti, C. Harrison, D. Kakkad, A. Zanella, G. Vietri, G. Lanzuisi, M. Salvato, M. Brusa, S. Carniani, C. Cicone, G. Cresci, C. Feruglio, B. Husemann, F. Mannucci, A. Marconi, M. Perna, E. Piconcelli, A. Puglisi, A. Saintonge, M. Schramm, C. Vignali, L. Zappacosta","doi":"10.1051/0004-6361/202039270","DOIUrl":"https://doi.org/10.1051/0004-6361/202039270","url":null,"abstract":"Feedback from AGN is thought to be key in shaping the life cycle of their host galaxies by regulating star-formation activity. Therefore, to understand the impact of AGN on star formation, it is essential to trace the molecular gas out of which stars form. In this paper we present the first systematic study of the CO properties of AGN hosts at z~2 for a sample of 27 X-ray selected AGN spanning two orders of magnitude in AGN bolometric luminosity (Lbol= 10^44.7-10^46.9 erg/s) by using ALMA Band 3 observations of the CO(3-2) transition (~1\" angular resolution). To search for evidence of AGN feedback on the CO properties of the host galaxies, we compared our AGN with a sample of inactive (i.e., non-AGN) galaxies from the PHIBSS survey with similar redshift, stellar masses, and SFRs. We used the same CO transition as a consistent proxy for the gas mass for the two samples in order to avoid systematics involved when assuming conversion factors. By adopting a Bayesian approach to take upper limits into account, we analyzed CO luminosities as a function of stellar masses and SFRs, as well as the ratio LCO(3-2)/M* (proxy for the gas fraction). The two samples show statistically consistent trends in the LCO(3-2)-Lfir and LCO(3-2)-M* planes. However, there are indications that AGN feature lower CO(3-2) luminosities (0.4-0.7 dex) than inactive galaxies at the 2-3sigma level when we focus on the subset of parameters where the results are better constrained and on the distribution of the mean LCO(3-2)/M*. Therefore, even by conservatively assuming the same excitation factor r31, we would find lower molecular gas masses in AGN, and assuming higher r31 would exacerbate this difference. We interpret our result as a hint of the potential effect of AGN activity (e.g., radiation and outflows), which may be able to heat, excite, dissociate, and/or deplete the gas reservoir of the host galaxies. (abridged)","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85986637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zeleke Beyoro-Amado, M. S'anchez-Portal, Á. Bongiovanni, M. Povi'c, S. B. Tessema, R. Pérez-Martínez, Ana María Pérez García, M. Cerviño, J. Nadolny, J. Cepa, J. I. Gonz'alez-Serrano, I. Pintos-Castro
Although ZwCl0024+1652 galaxy cluster at $zsim0.4$ has been thoroughly analysed, it lacks a comprehensive study of star formation and nuclear activity of its members. With GaLAxy Cluster Evolution (GLACE) survey, a total of 174 H$alpha$ emission-line galaxies (ELGs) were detected, most of them having [NII}]. We reduced and analysed a set of [OIII] and H$beta$ tunable filter (TF) observations within GLACE survey. Using H$alpha$ priors, we identified [OIII] and H$beta$ in 35 ($sim$20%) and 59 ($sim$34%) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [NII]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40% star-forming (SF), 55% composites, and 5% LINERs. Star formation rate (SFR) measured through extinction corrected H$alpha$ fluxes increases with stellar mass ($mathrm{M}_{*}$), attaining its peak at $mathrm{M}_{*}sim10^{9.8}mathrm{M}_odot$. We observed that the cluster centre to $sim$1.3Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high $mathrm{M}_*$, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with $mathrm{M}_*$ while specific SFR (sSFR) anti-correlates with $mathrm{M}_*$, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H$beta$ and/or [OIII] lines in ZwCl0024+1652 cluster.
虽然已经对位于$zsim0.4$的ZwCl0024+1652星系团进行了彻底的分析，但它缺乏对恒星形成和其成员核活动的全面研究。星系团演化(GLACE)巡天共探测到174个H $alpha$发射线星系(elg)，其中大多数具有[NII｝]。我们减少并分析了GLACE调查中的一组[OIII]和H $beta$可调滤波器(TF)观测结果。利用H $alpha$先验，我们在35 ($sim$ 20)中识别出[OIII]和H $beta$%) and 59 ($sim$34%) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [NII]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40% star-forming (SF), 55% composites, and 5% LINERs. Star formation rate (SFR) measured through extinction corrected H$alpha$ fluxes increases with stellar mass ($mathrm{M}_{*}$), attaining its peak at $mathrm{M}_{*}sim10^{9.8}mathrm{M}_odot$. We observed that the cluster centre to $sim$1.3Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high $mathrm{M}_*$, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with $mathrm{M}_*$ while specific SFR (sSFR) anti-correlates with $mathrm{M}_*$, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H$beta$ and/or [OIII] lines in ZwCl0024+1652 cluster.
{"title":"GLACE survey: Galaxy activity in ZwCl0024+1652 cluster from strong optical emission lines","authors":"Zeleke Beyoro-Amado, M. S'anchez-Portal, Á. Bongiovanni, M. Povi'c, S. B. Tessema, R. Pérez-Martínez, Ana María Pérez García, M. Cerviño, J. Nadolny, J. Cepa, J. I. Gonz'alez-Serrano, I. Pintos-Castro","doi":"10.1093/mnras/staa3812","DOIUrl":"https://doi.org/10.1093/mnras/staa3812","url":null,"abstract":"Although ZwCl0024+1652 galaxy cluster at $zsim0.4$ has been thoroughly analysed, it lacks a comprehensive study of star formation and nuclear activity of its members. With GaLAxy Cluster Evolution (GLACE) survey, a total of 174 H$alpha$ emission-line galaxies (ELGs) were detected, most of them having [NII}]. We reduced and analysed a set of [OIII] and H$beta$ tunable filter (TF) observations within GLACE survey. Using H$alpha$ priors, we identified [OIII] and H$beta$ in 35 ($sim$20%) and 59 ($sim$34%) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [NII]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40% star-forming (SF), 55% composites, and 5% LINERs. Star formation rate (SFR) measured through extinction corrected H$alpha$ fluxes increases with stellar mass ($mathrm{M}_{*}$), attaining its peak at $mathrm{M}_{*}sim10^{9.8}mathrm{M}_odot$. We observed that the cluster centre to $sim$1.3Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high $mathrm{M}_*$, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with $mathrm{M}_*$ while specific SFR (sSFR) anti-correlates with $mathrm{M}_*$, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H$beta$ and/or [OIII] lines in ZwCl0024+1652 cluster.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86578313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1051/0004-6361/202039341
E. L. Hunt, S. Reffert
The census of open clusters in the Milky Way is in a never-before seen state of flux. Recent works have reported hundreds of new open clusters thanks to the incredible astrometric quality of the Gaia satellite, but other works have also reported that many open clusters discovered in the pre Gaia era may be associations. We aim to conduct a comparison of clustering algorithms used to detect open clusters, attempting to statistically quantify their strengths and weaknesses by deriving the sensitivity, specificity, and precision of each as well as their true positive rate against a larger sample. We selected DBSCAN, HDBSCAN, and Gaussian mixture models for further study, owing to their speed and appropriateness for use with Gaia data. We developed a preprocessing pipeline for Gaia data and developed the algorithms further for the specific application to open clusters. We derived detection rates for all 1385 open clusters in the fields in our study as well as more detailed performance statistics for 100 of these open clusters. DBSCAN was sensitive to 50% to 62% of the true positive open clusters in our sample, with generally very good specificity and precision. HDBSCAN traded precision for a higher sensitivity of up to 82%, especially across different distances and scales of open clusters. Gaussian mixture models were slow and only sensitive to 33% of open clusters in our sample, which tended to be larger objects. Additionally, we report on 41 new open cluster candidates detected by HDBSCAN, three of which are closer than 500 pc. When used with additional post-processing to mitigate its false positives, we have found that HDBSCAN is the most sensitive and effective algorithm for recovering open clusters in Gaia data. Our results suggest that many more new and already reported open clusters have yet to be detected in Gaia data.
{"title":"Improving the open cluster census","authors":"E. L. Hunt, S. Reffert","doi":"10.1051/0004-6361/202039341","DOIUrl":"https://doi.org/10.1051/0004-6361/202039341","url":null,"abstract":"The census of open clusters in the Milky Way is in a never-before seen state of flux. Recent works have reported hundreds of new open clusters thanks to the incredible astrometric quality of the Gaia satellite, but other works have also reported that many open clusters discovered in the pre Gaia era may be associations. We aim to conduct a comparison of clustering algorithms used to detect open clusters, attempting to statistically quantify their strengths and weaknesses by deriving the sensitivity, specificity, and precision of each as well as their true positive rate against a larger sample. We selected DBSCAN, HDBSCAN, and Gaussian mixture models for further study, owing to their speed and appropriateness for use with Gaia data. We developed a preprocessing pipeline for Gaia data and developed the algorithms further for the specific application to open clusters. We derived detection rates for all 1385 open clusters in the fields in our study as well as more detailed performance statistics for 100 of these open clusters. DBSCAN was sensitive to 50% to 62% of the true positive open clusters in our sample, with generally very good specificity and precision. HDBSCAN traded precision for a higher sensitivity of up to 82%, especially across different distances and scales of open clusters. Gaussian mixture models were slow and only sensitive to 33% of open clusters in our sample, which tended to be larger objects. Additionally, we report on 41 new open cluster candidates detected by HDBSCAN, three of which are closer than 500 pc. When used with additional post-processing to mitigate its false positives, we have found that HDBSCAN is the most sensitive and effective algorithm for recovering open clusters in Gaia data. Our results suggest that many more new and already reported open clusters have yet to be detected in Gaia data.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73875005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Kielty, K. Venn, F. Sestito, E. Starkenburg, N. Martin, D. Aguado, A. Arentsen, S. Fabbro, J. I. González Hernández, V. Hill, P. Jablonka, C. Lardo, L. Mashonkina, J. Navarro, C. Sneden, G. Thomas, K. Youakim, Spencer Bialek, R. Sánchez-Janssen
High-resolution optical spectra of 30 metal-poor stars selected from the textit{Pristine} survey are presented, based on observations taken with the Gemini Observatory GRACES spectrograph. Stellar parameters T$_{rm eff}$ and $log g$ are determined using Gaia DR2 parallaxes and MIST/MESA metal-poor isochrones. GRACES spectra are used to determine chemical abundances (or upper-limits) for 20 elements (Li, O, Na, Mg, K, Ca, Ti, Sc, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Ba, La, Nd, Eu). These stars are confirmed to be metal-poor ([Fe/H]$<-2.5$), with higher precision than from earlier medium-resolution analyses. The chemistry for most targets is similar to that of other extremely metal-poor stars in the Galactic halo. Two stars near [Fe/H]$=-3.0$ have unusually low Ca and high Mg, suggestive of contributions from few SN~II, where alpha-element formation through hydrostatic nucleosynthesis was more efficient. Three new carbon-enhanced metal-poor stars are also identified (two CEMP-s and one potential CEMP-no star), when our chemical abundances are combined with carbon from previous medium-resolution analyses. The GRACES spectra also provide precision radial velocities ($sigma_{rm RV}le0.2$ km s$^{-1}$) for dynamical orbit calculations with the Gaia DR2 proper motions. Most of our targets are dynamically associated with the Galactic halo; however, five stars with [Fe/H]$<-3$ have planar-like orbits, including one retrograde planar star. Another five stars are dynamically consistent with the Gaia-Sequoia accretion event; three have typical high [$alpha$/Fe] ratios for their metallicities, whereas two are [Mg/Fe]-deficient, and one is a new CEMP-s candidate. These results are discussed in terms of the formation and early chemical evolution of the Galaxy.
根据双子座天文台GRACES光谱仪的观测结果，展示了从textit{原始}调查中选择的30颗金属贫乏恒星的高分辨率光谱。恒星参数T $_{rm eff}$和$log g$是使用盖亚DR2视差和MIST/MESA等时线确定的。grace光谱用于确定20种元素(Li, O, Na, Mg, K, Ca, Ti, Sc, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Ba, La, Nd, Eu)的化学丰度(或上限)。这些恒星被证实是金属贫乏的([Fe/H] $<-2.5$)，比早期的中等分辨率分析精度更高。大多数目标的化学性质与银河晕中其他极度缺乏金属的恒星相似。在[Fe/H] $=-3.0$附近的两颗恒星有异常低的Ca和高的Mg，暗示了SN II的贡献，其中通过流体静力核合成的α元素形成更有效。当我们的化学丰度与之前中等分辨率分析的碳相结合时，还发现了三颗新的碳增强金属贫星(两颗cmp -s星和一颗潜在的cmp -无星)。GRACES光谱还提供了精确的径向速度($sigma_{rm RV}le0.2$ km s $^{-1}$)，用于盖亚DR2固有运动的动态轨道计算。我们的大多数目标都与银河晕动态地联系在一起;然而，有五颗[Fe/H] $<-3$的恒星有类似平面的轨道，包括一颗逆行的平面恒星。另外5颗恒星与Gaia-Sequoia吸积事件动态一致;三种金属丰度具有典型的高[$alpha$ /Fe]比率，而两种是[Mg/Fe]缺乏，一种是新的cmp -s候选者。这些结果将从银河系的形成和早期化学演化的角度进行讨论。
{"title":"The Pristine survey – XII. Gemini-GRACES chemo-dynamical study of newly discovered extremely metal-poor stars in the Galaxy","authors":"C. Kielty, K. Venn, F. Sestito, E. Starkenburg, N. Martin, D. Aguado, A. Arentsen, S. Fabbro, J. I. González Hernández, V. Hill, P. Jablonka, C. Lardo, L. Mashonkina, J. Navarro, C. Sneden, G. Thomas, K. Youakim, Spencer Bialek, R. Sánchez-Janssen","doi":"10.1093/mnras/stab1783","DOIUrl":"https://doi.org/10.1093/mnras/stab1783","url":null,"abstract":"High-resolution optical spectra of 30 metal-poor stars selected from the textit{Pristine} survey are presented, based on observations taken with the Gemini Observatory GRACES spectrograph. Stellar parameters T$_{rm eff}$ and $log g$ are determined using Gaia DR2 parallaxes and MIST/MESA metal-poor isochrones. GRACES spectra are used to determine chemical abundances (or upper-limits) for 20 elements (Li, O, Na, Mg, K, Ca, Ti, Sc, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Ba, La, Nd, Eu). These stars are confirmed to be metal-poor ([Fe/H]$<-2.5$), with higher precision than from earlier medium-resolution analyses. The chemistry for most targets is similar to that of other extremely metal-poor stars in the Galactic halo. Two stars near [Fe/H]$=-3.0$ have unusually low Ca and high Mg, suggestive of contributions from few SN~II, where alpha-element formation through hydrostatic nucleosynthesis was more efficient. Three new carbon-enhanced metal-poor stars are also identified (two CEMP-s and one potential CEMP-no star), when our chemical abundances are combined with carbon from previous medium-resolution analyses. The GRACES spectra also provide precision radial velocities ($sigma_{rm RV}le0.2$ km s$^{-1}$) for dynamical orbit calculations with the Gaia DR2 proper motions. Most of our targets are dynamically associated with the Galactic halo; however, five stars with [Fe/H]$<-3$ have planar-like orbits, including one retrograde planar star. Another five stars are dynamically consistent with the Gaia-Sequoia accretion event; three have typical high [$alpha$/Fe] ratios for their metallicities, whereas two are [Mg/Fe]-deficient, and one is a new CEMP-s candidate. These results are discussed in terms of the formation and early chemical evolution of the Galaxy.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91497821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Dharmawardena, M. Barlow, J. Drew, A. Seales, S. Sale, David Jones, A. Mampaso, Q. Parker, L. Sabin, R. Wesson
We report H$alpha$ filter photometry for 197 northern hemisphere planetary nebulae (PNe) obtained using imaging data from the IPHAS survey. H$alpha$+[N II] fluxes were measured for 46 confirmed or possible PNe discovered by the IPHAS survey and for 151 previously catalogued PNe that fell within the area of the northern Galactic Plane surveyed by IPHAS. After correcting for [N II] emission admitted by the IPHAS H$alpha$ filter, the resulting H$alpha$ fluxes were combined with published radio free-free fluxes and H$beta$ fluxes, in order to estimate mean optical extinctions to 143 PNe using ratios involving their integrated Balmer line fluxes and their extinction-free radio fluxes. Distances to the PNe were then estimated using three different 3D interstellar dust extinction mapping methods, including the IPHAS-based H-MEAD algorithm of Sale (2014). These methods were used to plot dust extinction versus distance relationships for the lines of sight to the PNe; the intercepts with the derived dust optical extinctions allowed distances to the PNe to be inferred. For 17 of the PNe in our sample reliable Gaia DR2 distances were available and these have been compared with the distances derived using three different extinction mapping algorithms as well as with distances from the nebular radius vs. H$alpha$ surface brightness relation of Frew et al. (2016). That relation and the H-MEAD extinction mapping algorithm yielded the closest agreement with the Gaia DR2 distances.
我们报告了利用IPHAS调查的成像数据获得的197个北半球行星状星云(PNe)的H $alpha$滤光器光度测定。对IPHAS调查发现的46个已确认或可能发现的PNe以及IPHAS调查的位于北银道面区域内的151个先前编目的PNe测量了H $alpha$ +[N II]通量。在对IPHAS H $alpha$滤波器接收的[N II]发射进行校正后，将得到的H $alpha$通量与公布的射电自由通量和H $beta$通量结合起来，利用它们的综合巴尔默线通量和它们的无消光射电通量的比值来估计平均光学消光到143 PNe。然后使用三种不同的3D星际尘埃消光映射方法估计到海王星的距离，包括Sale(2014)基于iphasus的H-MEAD算法。这些方法用于绘制尘埃消退与PNe视线距离的关系;通过对尘埃光学消光的截取，可以推断出星云ne的距离。对于我们样本中的17个PNe，可以获得可靠的Gaia DR2距离，并将这些距离与使用三种不同消光映射算法获得的距离以及距离星云半径与H $alpha$表面亮度关系(Frew et al.， 2016)进行了比较。这种关系和H-MEAD消光映射算法得出了与盖亚DR2距离最接近的结果。
{"title":"H α fluxes and extinction distances for planetary nebulae in the IPHAS survey of the northern galactic plane","authors":"T. Dharmawardena, M. Barlow, J. Drew, A. Seales, S. Sale, David Jones, A. Mampaso, Q. Parker, L. Sabin, R. Wesson","doi":"10.1093/mnras/staa3820","DOIUrl":"https://doi.org/10.1093/mnras/staa3820","url":null,"abstract":"We report H$alpha$ filter photometry for 197 northern hemisphere planetary nebulae (PNe) obtained using imaging data from the IPHAS survey. H$alpha$+[N II] fluxes were measured for 46 confirmed or possible PNe discovered by the IPHAS survey and for 151 previously catalogued PNe that fell within the area of the northern Galactic Plane surveyed by IPHAS. After correcting for [N II] emission admitted by the IPHAS H$alpha$ filter, the resulting H$alpha$ fluxes were combined with published radio free-free fluxes and H$beta$ fluxes, in order to estimate mean optical extinctions to 143 PNe using ratios involving their integrated Balmer line fluxes and their extinction-free radio fluxes. Distances to the PNe were then estimated using three different 3D interstellar dust extinction mapping methods, including the IPHAS-based H-MEAD algorithm of Sale (2014). These methods were used to plot dust extinction versus distance relationships for the lines of sight to the PNe; the intercepts with the derived dust optical extinctions allowed distances to the PNe to be inferred. For 17 of the PNe in our sample reliable Gaia DR2 distances were available and these have been compared with the distances derived using three different extinction mapping algorithms as well as with distances from the nebular radius vs. H$alpha$ surface brightness relation of Frew et al. (2016). That relation and the H-MEAD extinction mapping algorithm yielded the closest agreement with the Gaia DR2 distances.","PeriodicalId":8452,"journal":{"name":"arXiv: Astrophysics of Galaxies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73811202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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