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The influences of convective overshooting and semiconvection on the chemical evolution of massive stars

Research in Astronomy and Astrophysics 2014年第8期14卷 979-991页

作者： Cai-Yun Ding Yan Li Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

In massive stars, convection in the interior is different from that of inter- mediate and small mass stars. In the main-sequence phase of small mass stars, there is a convective core and a radiative envelope, between which are the radiative inter- mediate layers with uneven chemical abundances. Semiconvection would occur in the intermediate layers between the convective core and the homogeneous envelope in massive stars. We treat core convective overshooting and semiconvection together as a process. We found that when decreasing overshooting, the semiconvection is more pronounced. In these two processes, we introduce one diffusive parameter D, which is different from other authors who have introduced different parameters for these two zones. The influences of the turbulent diffusion process on chemical evolution and other quantities of the stellar structure are shown in the present paper.

关键词： stars evolution -- stars abundances -- convection -- diffusion

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New estimates of scale heights and spiral structures for non-edge-on spiral galaxies

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Research in Astronomy and Astrophysics 2014年第7期14卷 869-874页

作者： Tao Hu Qiu-He Peng Department of Automation Shanghai University Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesYunnan Observatories Department of Astronomy Nanjing University

On the basis of Poisson＇s equation for the logarithmic perturbation of matter density, we provide improved estimates of scale heights and spiral structures for non-edge-on spiral galaxies by subtracting the surface brightness distributions from observed images. As examples, the non-edge-on spiral galaxies PGC 24996, which is face-on, and M31, which is inclined, are studied. The scale height, pitch angle and inclination angle of M31, our nearest neighbor, that are presented in this work, agree well with previous research.

关键词： galaxy： disk -- galaxies： fundamental parameters -- galaxies： spiral --galaxies： structure

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MILLISECOND PULSAR ORIGIN OF THE GALACTIC CENTER EXCESS AND EXTENDED GAMMA-RAY EMISSION FROM ANDROMEDA – A CLOSER LOOK

arXiv

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arXiv 2017年

作者： Eckner, Christopher Hou, Xian Serpico, Pasquale D. Winter, Miles Zaharijas, Gabrijela Martin, Pierrick di Mauro, Mattia Mirabal, Nestor Petrovic, Jovana Prodanovic, Tijana Vandenbroucke, Justin Laboratory for Astroparticle Physics University of Nova Gorica Vipavska 13 Nova GoricaSI-5000 Slovenia Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunmin650216 P China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China LAPTh Université Savoie Mont Blanc & CNRS Annecy Cedex74941 France Universit of Wisconsin Madison 500 Lincoln Drive MadisonWI53706 United States Istituto Nazionale di Fisica Nucleare - Sezione Trieste Padriciano 99 TriesteI-34149 Italy Institut de Recherche en Astrophysique et Planétologie CNRS-INSU Université Paul Sabatier 9 avenue Colonel Roche Toulouse Cedex 4BP 4434631028 France W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States CRESST/CSST Department of Physics UMBC BaltimoreMD21250 United States NASA Goddard Space Flight Center GreenbeltMD20771 United States Department of Physics Faculty of Sciences University of Novi Sad Trg Dositeja Obradovića 4 Novi Sad21000 Serbia

A new measurement of a spatially extended gamma-ray signal from the center of the Andromeda galaxy (M31) has been recently published by the Fermi-LAT collaboration, reporting that the emission broadly resembles the so-called Galactic center excess (GCE) of the Milky Way (MW). Steadily, the weight of the evidence is accumulating on a millisecond pulsar (MSPs) origin for the GCE. These elements prompt us to compare the mentioned observations with what is, perhaps, the simplest model for an MSP population, solely obtained by rescaling of the MSP luminosity function determined in the local MW disk via the respective stellar mass of the systems. Remarkably, we find that without free fitting parameters, this model can account for both the energetics and the morphology of the GCE within uncertainties. For M31, the estimated luminosity due to primordial MSPs is expected to contribute only about a quarter of the detected emission, although a stronger contribution cannot be excluded given the large uncertainties. If correct, the model predicts that the M31 disk emission due to MSPs is not far below the present upper bound. We also discuss additional refinements of this simple model. Using the correlation between globular cluster gamma-ray luminosity and stellar encounter rate, we gauge the dynamical MSP formation in the bulge. This component is expected to contribute to the GCE only at a level . 5%, but it could affect the signal’s morphology. We also comment on limitations of our model as well as on future perspectives for improved diagnostics. Subject headings: galaxies: Milky Way and dwarf spheroidal — gamma-rays: millisecond pulsars — X-rays: binaries Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

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The kepler program for observing interesting CVs 3

The kepler program for observing interesting CVs

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3rd Conference on Golden Age of Cataclysmic Variables and Related objects, Golden 2015

作者： Dai, Zhibin Szkody, Paula Garnavich, Peter M. Kennedy, Mark Yunnan Observatories Chinese Academy of Sciences P. O. Box 110 Kunming650011 China University of Washington SeattleWA98195 United States University of Notre Dame Notre DameIN46556 United States Department of Physics University College Cork Cork Ireland Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences China

Kepler K2 space telescope observations of cataclysmic variables (CVs) were used to search for periodic behavior and identify possible pseudo periods due to the satellite artefacts from periodic thrusters. Detailed period analyses were carried out for the dwarf nova UV Gem observed in the long cadence (LC) of the K2 campaign 0 (K2-C0) and seven CVs, comprised of four faint CVs and three known dwarf novae QZ Vir, RZ Leo and TW Vir observed in the long and short cadences (LC and SC) of the K2 campaign 1 (K2-C1), respectively. All 23 signals including harmonics and beat periods were identified from the periodograms of the four faint CVs in K2-C1. Among these 23 periods, there were eight signals distinctly detected from the periodogram of J1125-0016 due to a possible resonance between its orbital period and the common 5.9-hr satellite thruster period. A series of periodic dips with varying profiles obeying a period of 3.9256 day were found in all three SC light curves of K2-C1, which were extracted from the original K2 data files. This period is due to a periodic short-timescale resetting of the thruster. A two-dimensional power spectrum of the dwarf nova UV Gem observed in K2-C0 with a moving window of 4.7 day was derived for demonstrating the variations of the two significant modulations at the periods of 2.07 hr and 2.12 hr during the outburst and quiescent phases. In addition, the other two newly detected weak but consistent signals at the periods of 1.06hr and 0.91 hr were seen, likely due to the first harmonic of the 2.12 hr period and the fifth harmonic of the 6-hr thruster event of the satellite, respectively. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Satellites

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Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole

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Physical Review Letters 2020年第14期125卷 141104-141104页

作者： Dimitrios Psaltis Lia Medeiros Pierre Christian Feryal Özel Kazunori Akiyama Antxon Alberdi Walter Alef Keiichi Asada Rebecca Azulay David Ball Mislav Baloković John Barrett Dan Bintley Lindy Blackburn Wilfred Boland Geoffrey C. Bower Michael Bremer Christiaan D. Brinkerink Roger Brissenden Silke Britzen Dominique Broguiere Thomas Bronzwaer Do-Young Byun John E. Carlstrom Andrew Chael Chi-kwan Chan Shami Chatterjee Koushik Chatterjee Ming-Tang Chen Yongjun Chen Ilje Cho John E. Conway James M. Cordes Geoffrey B. Crew Yuzhu Cui Jordy Davelaar Mariafelicia De Laurentis Roger Deane Jessica Dempsey Gregory Desvignes Jason Dexter Ralph P. Eatough Heino Falcke Vincent L. Fish Ed Fomalont Raquel Fraga-Encinas Per Friberg Christian M. Fromm Charles F. Gammie Roberto García Olivier Gentaz Ciriaco Goddi José L. Gómez Minfeng Gu Mark Gurwell Kazuhiro Hada Ronald Hesper Luis C. Ho Paul Ho Mareki Honma Chih-Wei L. Huang Lei Huang David H. Hughes Makoto Inoue Sara Issaoun David J. James Buell T. Jannuzi Michael Janssen Wu Jiang Alejandra Jimenez-Rosales Michael D. Johnson Svetlana Jorstad Taehyun Jung Mansour Karami Ramesh Karuppusamy Tomohisa Kawashima Garrett K. Keating Mark Kettenis Jae-Young Kim Junhan Kim Jongsoo Kim Motoki Kino Jun Yi Koay Patrick M. Koch Shoko Koyama Michael Kramer Carsten Kramer Thomas P. Krichbaum Cheng-Yu Kuo Tod R. Lauer Sang-Sung Lee Yan-Rong Li Zhiyuan Li Michael Lindqvist Rocco Lico Jun Liu Kuo Liu Elisabetta Liuzzo Wen-Ping Lo Andrei P. Lobanov Colin Lonsdale Ru-Sen Lu Jirong Mao Sera Markoff Daniel P. Marrone Alan P. Marscher Iván Martí-Vidal Satoki Matsushita Yosuke Mizuno Izumi Mizuno James M. Moran Kotaro Moriyama Monika Moscibrodzka Cornelia Müller Gibwa Musoke Alejandro Mus Mejías Hiroshi Nagai Neil M. Nagar Ramesh Narayan Gopal Narayanan Iniyan Natarajan Roberto Neri Aristeidis Noutsos Hiroki Okino Héctor Olivares Tomoaki Oyama Daniel C. M. Palumbo Jongho Park Nimesh Patel Ue-Li Pen Vincent Piétu Richard Plambeck Aleksandar PopStefanija Ben Prather Jorge A. Preciado-López Venkatessh Ramak Steward Observatory and Department of Astronomy University of Arizona 933 North Cherry Avenue Tucson Arizona 85721 USA School of Natural Sciences Institute for Advanced Study 1 Einstein Drive Princeton New Jersey 08540 USA National Radio Astronomy Observatory 520 Edgemont Road Charlottesville Virginia 22903 USA Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road Westford Massachusetts 01886 USA National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo 181-8588 Japan Black Hole Initiative at Harvard University 20 Garden Street Cambridge Massachusetts 02138 USA Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n E-18008 Granada Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 D-53121 Bonn Germany Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. IV Roosevelt Road Taipei 10617 Taiwan Republic of China Departament d’Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 E-46100 Burjassot València Spain Observatori Astronmic Universitat de València C. Catedrático José Beltrán 2 E-46980 Paterna València Spain Center for Astrophysics–Harvard & Smithsonian 60 Garden Street Cambridge Massachusetts 02138 USA East Asian Observatory 660 North A’ohoku Place Hilo Hawaii 96720 USA Nederlandse Onderzoekschool voor Astronomie (NOVA) P.O. Box 9513 2300 RA Leiden Netherlands Institute of Astronomy and Astrophysics Academia Sinica 645 North A’ohoku Place Hilo Hawaii 96720 USA Institut de Radioastronomie Millimétrique 300 rue de la Piscine F-38406 Saint Martin d’Hères France Department of Astrophysics Institute for Mathematics Astrophysics and Particle Physics (IMAPP) Radboud University P.O. Box 9010 6500 GL Nijmegen Netherlands Korea Astronomy and Space Science Institute Daedeok-daero 776 Yuseong-gu Daejeon 34055 Republic of Korea University of Science and Technology Gajeong-ro 217 Yuseong-gu Daejeon 34113 Re

The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. We use numerical calculations of regular, parametric, non-Kerr metrics to identify the common characteristic among these different parametrizations that control the predicted shadow size. We show that the shadow-size measurements place significant constraints on deviation parameters that control the second post-Newtonian and higher orders of each metric and are, therefore, inaccessible to weak-field tests. The new constraints are complementary to those imposed by observations of gravitational waves from stellar-mass sources.

关键词： Astrophysical studies of gravity Classical black holes Experimental studies of gravity Astronomical black holes

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Constraints on black-hole charges with the 2017 EHT observations of M87*

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Physical Review D 2021年第10期103卷 104047-104047页

作者： Prashant Kocherlakota Luciano Rezzolla Heino Falcke Christian M. Fromm Michael Kramer Yosuke Mizuno Antonios Nathanail Héctor Olivares Ziri Younsi Kazunori Akiyama Antxon Alberdi Walter Alef Juan Carlos Algaba Richard Anantua Keiichi Asada Rebecca Azulay Anne-Kathrin Baczko David Ball Mislav Baloković John Barrett Bradford A. Benson Dan Bintley Lindy Blackburn Raymond Blundell Wilfred Boland Katherine L. Bouman Geoffrey C. Bower Hope Boyce Michael Bremer Christiaan D. Brinkerink Roger Brissenden Silke Britzen Avery E. Broderick Dominique Broguiere Thomas Bronzwaer Do-Young Byun John E. Carlstrom Andrew Chael Chi-kwan Chan Shami Chatterjee Koushik Chatterjee Ming-Tang Chen Yongjun Chen (陈永军) Paul M. Chesler Ilje Cho Pierre Christian John E. Conway James M. Cordes Thomas M. Crawford Geoffrey B. Crew Alejandro Cruz-Osorio Yuzhu Cui Jordy Davelaar Mariafelicia De Laurentis Roger Deane Jessica Dempsey Gregory Desvignes Sheperd S. Doeleman Ralph P. Eatough Joseph Farah Vincent L. Fish Ed Fomalont Raquel Fraga-Encinas Per Friberg H. Alyson Ford Antonio Fuentes Peter Galison Charles F. Gammie Roberto García Olivier Gentaz Boris Georgiev Ciriaco Goddi Roman Gold José L. Gómez Arturo I. Gómez-Ruiz Minfeng Gu (顾敏峰) Mark Gurwell Kazuhiro Hada Daryl Haggard Michael H. Hecht Ronald Hesper Luis C. Ho (何子山) Paul Ho Mareki Honma Chih-Wei L. Huang Lei Huang (黄磊) David H. Hughes Shiro Ikeda Makoto Inoue Sara Issaoun David J. James Buell T. Jannuzi Michael Janssen Britton Jeter Wu Jiang (江悟) Alejandra Jimenez-Rosales Michael D. Johnson Svetlana Jorstad Taehyun Jung Mansour Karami Ramesh Karuppusamy Tomohisa Kawashima Garrett K. Keating Mark Kettenis Dong-Jin Kim Jae-Young Kim Jongsoo Kim Junhan Kim Motoki Kino Jun Yi Koay Yutaro Kofuji Patrick M. Koch Shoko Koyama Carsten Kramer Thomas P. Krichbaum Cheng-Yu Kuo Tod R. Lauer Sang-Sung Lee Aviad Levis Yan-Rong Li (李彦荣) Zhiyuan Li (李志远) Michael Lindqvist Rocco Lico Greg Lindahl Jun Liu (刘俊) Kuo Liu Elisabetta Liuzzo Wen-Ping Lo Andrei P. Lobanov Laurent Loinard Colin Lonsdale Ru-Sen Lu Institut für Theoretische Physik Goethe-Universität Max-von-Laue-Strasse 1 60438 Frankfurt Germany Frankfurt Institute for Advanced Studies Ruth-Moufang-Strasse 1 60438 Frankfurt Germany School of Mathematics Trinity College Dublin 2 Ireland Department of Astrophysics Institute for Mathematics Astrophysics and Particle Physics (IMAPP) Radboud University P.O. Box 9010 6500 GL Nijmegen Netherlands Black Hole Initiative at Harvard University 20 Garden Street Cambridge Massachusetts 02138 USA Center for Astrophysics—Harvard & Smithsonian 60 Garden Street Cambridge Massachusetts 02138 USA Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 D-53121 Bonn Germany Tsung-Dao Lee Institute and School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Institut für Theoretische Physik Goethe-Universität Frankfurt Max-von-Laue-Straße 1 D-60438 Frankfurt am Main Germany Department of Physics National and Kapodistrian University of Athens Panepistimiopolis GR 15783 Zografos Greece Mullard Space Science Laboratory University College London Holmbury St. Mary Dorking Surrey RH5 6NT United Kingdom Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road Westford Massachusetts 01886 USA National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo 181-8588 Japan Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n E-18008 Granada Spain Department of Physics Faculty of Science University of Malaya 50603 Kuala Lumpur Malaysia Center for Computational Astrophysics Flatiron Institute 162 Fifth Avenue New York New York 10010 USA Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd Taipei 10617 Taiwan R.O.C. Departament d’Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 E-46100 Burjassot València Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 E-46980 Paterna

Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M87* shadow size to infer constraints on the physical charges of a large variety of nonrotating or rotating black holes. For example, we show that the quality of the measurements is already sufficient to rule out that M87* is a highly charged dilaton black hole. Similarly, when considering black holes with two physical and independent charges, we are able to exclude considerable regions of the space of parameters for the doubly-charged dilaton and the Sen black holes.

关键词： Alternative gravity theories Experimental studies of gravity General relativity Radio, microwave, & sub-mm astronomy Accretion disk & black-hole plasma Classical black holes Galaxies Electromagnetic radiation astronomy

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On the non-synchronous rotation of binary systems

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Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1194-1200页

作者： LI ZhiXiong HUANG RunQian WANG ShuMin Department of Physics Yunnan University Yunnan Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

During the evolution of the binary system, many physical processes occur, which can influence the orbital angular velocity and the spin angular velocities of the two components, and influence the non-synchronous or synchronous rotation of the system. These processes include the transfer of masses and angular momentums between the component stars, the loss of mass and angular momentum via stellar winds, and the deformation of the structure of component stars. A study of these processes indicates that they are closely related to the combined effects of tide and rotation. This means, to study the synchronous or non-synchronous rotation of binary systems, one has to consider the contributions of different physical processes simultaneously, instead of the tidal effect alone. A way to know whether the rotation of a binary system is synchronous or non-synchronous is to calculate the orbital angular velocity and the spin angular velocities of the component stars. If all of these angular velocities are equal, the rotation of the system is synchronous. If not, the rotation of the system is non-synchronous. For this aim, a series of equations are developed to calculate the orbital and spin angular velocities. The evolutionary calculation of a binary system with masses of 10M~ ＋ 6Me shows that the transfer of masses and angular momentums between the two components, and the deformation of the components structure in the semidetached or in the contact phase can change the rotation of the system from synchronous into non-synchronous rotation.

关键词： stars： rotation stars： evolution stars： binaries

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Alma maps of dust and warm dense gas emission in the starburst galaxy ic 5179

arXiv

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arXiv 2017年

作者： Zhao, Yinghe Lu, Nanyao Diaz-Santos, Tanio Kevin Xu, C. Gao, Yu Charmandaris, Vassilis Van der Werf, Paul Zhang, Zhi-Yu Cao, Chen Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Center for Astronomical Mega-Science CAS 20A Datun Road Chaoyang District Beijing100012 China National Astronomical Observatories of China Chinese Academy of Sciences Beijing100012 China China-Chile Joint Center for Astronomy Chinese Academy of Sciences Camino El Observatorio 1515 Las Condes Santiago Chile Núcleo de Astronomia de la Facultad de Ingenieria Universidad Diego Portales Av. Ejército Libertador 441 Santiago Chile PurpleMountain Observatory Chinese Academy of Sciences Nanjing210008 China Department of Physics University of Crete HeraklionGR-71003 Greece IAASARS National Observatory of Athens PenteliGR-15236 Greece Leiden Observatory Leiden University P.O. Box 9513 Leiden2300 RA Netherlands Institute for Astronomy University of Edinburgh Royal Observatory Blackford Hill EdinburghEH9 3HJ United Kingdom 11 ESO Karl Schwarzschild Strasse 2 Garching MunichD-85748 Germany School of Space Science and Physics Shandong University at Weihai Weihai Shandong264209 China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Weihai Shandong264209 China

We present our high-resolution (0".15 × 0".13, ∼34 pc) observations of the CO (6-5) line emission, which probes the warm and dense molecular gas, and the 434 μm dust continuum emission in the nuclear region of the starburst galaxy IC 5179, conducted with the Atacama Large Millimeter Array (ALMA). The CO (6-5) emission is spatially distributed in filamentary structures with many dense cores and shows a velocity field that is characteristic of a circum-nuclear rotating gas disk, with 90% of the rotation speed arising within a radius of . 150 pc. At the scale of our spatial resolution, the CO (6-5) and dust emission peaks do not always coincide, with their surface brightness ratio varying by a factor of ∼10. This result suggests that their excitation mechanisms are likely different, as further evidenced by the Southwest to Northeast spatial gradient of both CO-to-dust continuum ratio and Pa-α equivalent width. Within the nuclear region (radius∼300 pc) and with a resolution of ∼34 pc, the CO line flux (dust flux density) detected in our ALMA observations is 180±18 Jy kms-1 (71 ± 7mJy), which account for 22% (2.4%) of the total value measured by Herschel. Copyright © 2017, The Authors. All rights reserved.

关键词： Dust

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The evolution of the spiral galaxy M51a

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Proceedings of the International Astronomical Union 2016年第S319期11卷 129-129页

作者： Xiaoyu Kang Fenghui Zhang Ruixiang Chang Yunnan Observatories CAS Kunming 650011 China email: kxyysl@*** Key Laboratory for the Structure and Evolution of Celestial Objects CAS China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory CAS 80 Nandan Road Shanghai 200030 China

A simple model for M51a is constructed to explore its evolutionary history by assuming its disk grows from continuous gas infall, which is shaped by a free parameter-the infall-peak time tp. By adopting a constant infall-peak time tp = 7.0Gyr, our model predictions can reproduce most of the observed constraints and still show that the disk of M51a forms inside-out. Our results also show that the current molecular gas surface density, the star-formation rate and the UV-band surface brightness are important quantities to trace the effect of recent interactions on galactic star-formation process.

关键词： galaxies: abundance galaxies: evolution galaxies: individual: M51a galaxies: spiral

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ALMA [N ii] 205 µm imaging spectroscopy of the interacting galaxy system BRI 1202-0725 at redshift 4.7

arXiv

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arXiv 2017年

作者： Lu, Nanyao Zhao, Yinghe Díaz-Santos, Tanio Xu, C. Kevin Charmandaris, Vassilis Gao, Yu van der Werf, Paul P. Privon, George C. Inami, Hanae Rigopoulou, Dimitra Sanders, David B. Zhu, Lei Beijing100012 China China-Chile Joint Center for Astronomy Camino El Observatorio 1515 Las Condes Santiago Chile Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Center for Astronomical Mega-Science CAS 20A Datun Road Chaoyang District Beijing100012 China Nucleo de Astronomia de la Facultad de Ingenieria Universidad Diego Portales Av. Ejercito Libertador 441 Santiago Chile Department of Physics University of Crete HeraklionGR-71003 Greece IAASARS National Observatory of Athens PenteliGR-15236 Greece Purple Mountain Observatory CAS Nanjing210008 China Leiden Observatory Leiden University PO Box 9513 Leiden2300 RA Netherlands Departamento de Astronomía Universidad de Concepción Casilla 160-C Concepción Chile Pontificia Universidad Católica de Chile Instituto de Astrofisica Casilla 306 Santiago 22 Chile Observatoire de Lyon CNRS UMR5574 Saint-Genis-LavalF-69230 France Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom University of Hawaii Institute for Astronomy 2680 Wood-lawn Drive HonoluluHI96822 United States

We present the results from Atacama Large Millimeter/submillimeter Array (ALMA) imaging in the [N ii] 205 µm fine-structure line (hereafter [N ii]) and the underlying continuum of BRI 1202-0725, an interacting galaxy system at z = 4.7, consisting of an optical QSO, a sub-millimeter galaxy (SMG) and two Lyman-α emitters (LAEs), all within ∼25 kpc of the QSO. We detect the QSO and SMG in both [N ii] and continuum. At the ∼1′′ (or 6.6 kpc) resolution, both QSO and SMG are resolved in [N ii], with the de-convolved major axes of ∼9 and ∼14 kpc, respectively. In contrast, their continuum emissions are much more compact and unresolved even at an enhanced resolution of ∼0.7′′. The ratio of the [N ii] flux to the existing CO (7−6) flux is used to constrain the dust temperature (Tdust) for a more accurate determination of the FIR luminosity LFIR. Our best estimated Tdust equals 43 (±2) K for both galaxies (assuming an emissivity index β = 1.8). The resulting LCO(7−6)/LFIR ratios are statistically consistent with that of local luminous infrared galaxies, confirming that LCO(7−6) traces the star formation (SF) rate (SFR) in these galaxies. We estimate that the on-going SF of the QSO (SMG) has a SFR of 5.1 (6.9) × 103 M๏ yr−1 (± 30%) assuming Chabrier initial mass function, takes place within a diameter (at half maximum) of 1.3 (1.5) kpc, and shall consume the existing 5 (5) × 1011 M๏ of molecular gas in 10 (7) × 107 years. Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

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