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arXiv 2017年

作者： Prentice, S.J. Ashall, C. Mazzali, P.A. Zhang, J.-J. James, P.A. Wang, X.-F. Vinko, J. Percival, S. Short, L. Piascik, A. Huang, F. Mo, J. Rui, L.-M. Wang, J.-G. Xiang, D.-F. Xin, Y.-X. Yi, W.-M. Yu, X.-G. Zhai, Q. Zhang, T.-M. Hosseinzadeh, G. Howell, D.A. McCully, C. Valenti, S. Cseh, B. Hanyecz, O. Kriskovics, L. Pal, A. Sarneczky, K. Sodor, A. Szakats, R. Szekely, P. Varga-Verebelyi, E. Vida, K. Bradac, M. Reichart, D.E. Sand, D. Tartaglia, L. Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL35RF United Kingdom Max-Planck-Institut fur Astrophysik Karl-Schwarzschild-Str. 1 GarchingD-85748 Germany Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Tsinghua University Beijing100084 China Chinese Academy of Sciences Beijing100012 China Las Cumbres Observatory 6740 Cortona Dr. Suite 102 GoletaCA93117 United States University of California Santa Barbara Department of Physics Broida Hall Santa BarbaraCA93111 United States Konkoly Observatory Research Centre for Astronomy and Earth Sciences Konkoly-Thegeut 15-17 Budapest1121 Hungary Department of Experimental Physics University of Szeged Domter 9 Szeged6720 Hungary Department of Optics and Quantum Electronics University of Szeged Domter 9 Szeged6720 Hungary Department of Astronomy University of Texas at Austin 2515 Speedway AustinTX78712-1205 United States Department of Physics University of California DavisCA95616 United States University of North Carolina 269 Phillips Hall CB #3255 Chapel HillNC27599 United States Department of Astronomy Steward Observatory 933 North Cherry Avenue Room N204 TucsonAZ85721-0065 United States Department of Physics Florida State University TallahasseeFL32306 United States

The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp, from ∼ 2 to ∼ 450 days after explosion, are presented along with analysis of its physical properties. The SN shows the broad lines associated with SNe Ic-3/4 but with a key difference. The early spectra display a strong absorption feature at ∼ 5400 A which is not seen in other SNe Ic-3/4 at this epoch. This feature has been attributed to He i in the literature. Spectral modelling of the SN in the early photospheric phase suggests the presence of residual He in a C/O dominated shell. However, the behaviour of the He i lines is unusual when compared with He-rich SNe, showing relatively low velocities and weakening rather than strengthening over time. The SN is found to rise to peak ∼ 16 d after core-collapse reaching a bolometric luminosity of Lp ∼ 3 × 1042erg s-1. Spectral models, including the nebular epoch, show that the SN ejected 2.5-4 Mo of material, with ∼ 1.5 Mo below 5000 km s-1, and with a kinetic energy of (4.5-7) × 1051erg. The explosion synthesised ∼ 0.14 Mo of 56Ni. There are significant uncertainties in E (B-V)host and the distance however, which will affect Lp and MNi. SN 2016coi exploded in a host similar to the Large Magellanic Cloud (LMC) and away from star-forming regions. The properties of the SN and the host-galaxy suggest that the progenitor had MZAMS of 23-28 Mo and was stripped almost entirely down to its C/O core at explosion. Copyright © 2017, The Authors. All rights reserved.

关键词： Supernovae

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Ephemeris refinement of 21 hot Jupiter exoplanets with high timing uncertainties

arXiv

引用

arXiv 2018年

作者： Mallonn, M. von Essen, C. Herrero, E. Alexoudi, X. Granzer, T. Sosa, M. Strassmeier, K.G. Bakos, G. Bayliss, D. Brahm, R. Bretton, M. Campos, F. Carone, L. Colón, K.D. Dale, H.A. Dragomir, D. Espinoza, N. Evans, P. Garcia, F. Gu, S.-H. Guerra, P. Jongen, Y. Jordán, A. Kang, W. Keles, E. Kim, T. Lendl, M. Molina, D. Salisbury, M. Scaggiante, F. Shporer, A. Siverd, R. Sokov, E. Sokova, I. Wünsche, A. Leibniz-Institut für Astrophysik Potsdam An der Sternwarte 16 PotsdamD-14482 Germany Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Ny Munkegade 120 Aarhus CDK-8000 Denmark Campus UAB Carrer de Can Magrans sn Cerdanyola del Vallès08193 Spain C/Gran Capitá 2-4 Edif. Nexus Barcelona08034 Spain Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque B1900FWA La Plata Argentina Paseo del Bosque B1900FWA La Plata Argentina Department of Astrophysical Sciences Princeton University 4 Ivy Lane PrincetonNJ08544 United States Dept. of Physics University of Warwick Gibbet Hill Road CoventryCV4 7AL United Kingdom Center of Astro-Engineering UC Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Macul Santiago7820436 Chile Instituto de Astrofísica Facultad de Física Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Macul Santiago7820436 Chile Millennium Institute of Astrophysics Av. Vicuña Mackenna 4860 Macul Santiago782-0436 Chile Observatoire des Baronnies provencales Observatoire Astronomique Moydans05150 France Observatory Puig d’Agulles Carrer Riera 1 Vallirana08759 Spain Max-Planck-Institut für Astronomie Königstuhl 17 Heidelberg69117 Germany NASA Goddard Space Flight Center Exoplanets and Stellar Astrophysics Laboratory GreenbeltMD20771 United States Emory University Department of Physics 400 Dowman Drive Suite N218 AtlantaGA30322 United States Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States Rarotonga Observatory PO Box 876 Rarotonga Cook Islands La Vara Valdes Observatory 33784 Muñas de Arriba ValdésAsturias Spain Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China University of Chinese Academy of Sciences B

Transit events of extrasolar planets offer a wealth of information for planetary characterization. However, for many known targets, the uncertainty of their predicted transit windows prohibits an accurate scheduling of follow-up observations. In this work, we refine the ephemerides of 21 hot Jupiter exoplanets with the largest timing uncertainties. We collected 120 professional and amateur transit light curves of the targets of interest, observed with a range of telescopes of 0.3m to 2.2m, and analyzed them along with the timing information of the planets discovery papers. In the case of WASP-117b, we measured a timing deviation compared to the known ephemeris of about 3.5 hours, and for HAT-P-29b and HAT-P-31b the deviation amounted to about 2 hours and more. For all targets, the new ephemeris predicts transit timings with uncertainties of less than 6 minutes in the year 2018 and less than 13 minutes until 2025. Thus, our results allow for an accurate scheduling of follow-up observations in the next decade. .EP] 4 Ja Copyright © 2018, The Authors. All rights reserved.

关键词： Satellites

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Far-UV radiation from hot subdwarf stars in early-type galaxies

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Proceedings of the International Astronomical Union 2015年第H16期10卷 124-124页

作者： Zhanwen Han Xuefei Chen Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan Observatory Kunming 650011 China email: zhanwenhan@*** cxf@***

Far-ultraviolet (FUV) excess is crucial to our understanding of early-type galaxies and it is widely believed that the FUV radiation originates mainly from hot subwarf stars. Hot subdwarf stars may form from binary interactions or from single star evolution. In the binary channel, a star near the tip of the first giant branch (FGB) may get its envelope removed by its companion via stable Roche lobe overflow or common envelope ejection, and then evolves to a hot subdwarf star (Han et al.2002, 2003, 2007). Such a process does not depend much on metallicity.

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JINGLE, a JCMT legacy survey of dust and gas for galaxy evolution studies: I. Survey overview and first results

arXiv

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arXiv 2018年

作者： Saintonge, Amélie Wilson, Christine D. Xiao, Ting Lin, Lihwai Hwang, Ho Seong Tosaki, Tomoka Bureau, Martin Cigan, Phillip J. Clark, Christopher J.R. Clements, David L. de Looze, Ilse Dharmawardena, Thavisha Gao, Yang Gear, Walter K. Greenslade, Joshua Lamperti, Isabella Lee, Jong Chul Li, Cheng Michalowski, Michal J. Mok, Angus Pan, Hsi-An Sansom, Anne E. Sargent, Mark Smith, Matthew W.L. Williams, Thomas Yang, Chentao Zhu, Ming Accurso, Gioacchino Barmby, Pauline Bourne, Nathan Brinks, Elias Brown, Toby Chung, Aeree Chung, Eun Jung Cibinel, Anna Coppin, Kristen Davies, Jonathan Davis, Timothy A. Eales, Steve Fanciullo, Lapo Fang, Taotao Gao, Yu Glass, David H.W. Gomez, Haley L. Greve, Thomas He, Jinhua Ho, Luis C. Huang, Feng Jeong, Hyunjin Jiang, Xuejian Jiao, Qian Kemper, Francisca Kim, Ji Hoon Kim, Minjin Kim, Taehyun Ko, Jongwan Kong, Xu Lacaille, Kevin Lacey, Cedric G. Lee, Bumhyun Lee, Joon Hyeop Lee, Wing-Kit Masters, Karen Oh, Se-Heon Papadopoulos, Padelis Park, Changbom Park, Sung-Joon Parsons, Harriet Rowlands, Kate Scicluna, Peter Scudder, Jillian M. Sethuram, Ramya Serjeant, Stephen Shao, Yali Sheen, Yun-Kyeong Shi, Yong Shim, Hyunjin Smith, Connor M.A. Spekkens, Kristine Tsai, An-Li Urquhart, Sheona Verma, Aprajita Violino, Giulio Viti, Serena Wake, David Wang, Junfeng Wouterloot, Jan Yang, Yujin Yim, Kijeong Yuan, Fangting Zheng, Zheng Department of Physics and Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Department of Physics and Astronomy McMaster University HamiltonONL8S 4M1 Canada Department of Physics Zhejiang University HangzhouZhejiang310027 China Institute of Astronomy and Astrophysics Academia Sinica P.O. Box 23-141 Taipei10617 Taiwan School of Physics Korea Institute for Advanced Study 85 Hoegiro Dongdaemun-gu Seoul02455 Korea Republic of Joetsu University of Education Yamayashiki-machi Joetsu Niigata943-8512 Japan Department of Physics Royal Military College of Canada PO Box 17000 Station Forces KingstonONK7K 7B4 Department of Astronomy Institute of Theoretical Physics and Astrophysics Xiamen University Xiamen361005 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210008 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210008 China Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan observatories Chinese Academy of Sciences P.O. Box 110 KunmingYunnan Province650011 China Camino El Observatorio 1515 Las Condes Santiago Chile Departamento de Astronomia Universidad de Chile Casilla 36-D Santiago Chile National Astronomical Observatory of China 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei230026 China Sterrenkundig Observatorium Universiteit Gent Krijgslaan 281 S9 GentB9000 Belgium Subaru Telescope National Astronomical Observatory of Japan 650 North A’ohoku Place HiloHI96720 United States Department of Astronomy Yonsei University 50 Yonsei-ro Seodaemun-gu Seoul03722 Korea Republic of Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-gu Daejeon34055 Korea Republic of National Central University No. 300 Zhongda Rd. Zhongli District Taoyuan City32001 Taiwan Department of Physic

JINGLE is a new JCMT legacy survey designed to systematically study the cold interstellar medium of galaxies in the local Universe. As part of the survey we perform 850µm continuum measurements with SCUBA-2 for a representative sample of 193 Herschel-selected galaxies with M∗ > 109M , as well as integrated CO(2-1) line fluxes with RxA3m for a subset of 90 of these galaxies. The sample is selected from fields covered by the Herschel-ATLAS survey that are also targeted by the MaNGA optical integral-field spectroscopic survey. The new JCMT observations combined with the multi-wavelength ancillary data will allow for the robust characterization of the properties of dust in the nearby Universe, and the benchmarking of scaling relations between dust, gas, and global galaxy properties. In this paper we give an overview of the survey objectives and details about the sample selection and JCMT observations, present a consistent 30 band UV-to-FIR photometric catalog with derived properties, and introduce the JINGLE Main Data Release (MDR). Science highlights include the non-linearity of the relation between 850µm luminosity and CO line luminosity (log LCO(2−1) = 1.372 log L850-1.376), and the serendipitous discovery of candidate z > 6 galaxies. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

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Detection and characterisation of oscillating red giants: first results from the TESS satellite

arXiv

引用

arXiv 2019年

作者： Aguirre, Víctor Silva Stello, Dennis Stokholm, Amalie Mosumgaard, Jakob R. Ball, Warrick H. Basu, Sarbani Bossini, Diego Bugnet, Lisa Buzasi, Derek Campante, Tiago L. Carboneau, Lindsey Chaplin, William J. Corsaro, Enrico Davies, Guy R. Elsworth, Yvonne García, Rafael A. Gaulme, Patrick Hall, Oliver J. Handberg, Rasmus Hon, Marc Kallinger, Thomas Kang, Liu Lund, Mikkel N. Mathur, Savita Mints, Alexey Mosser, Benoit Orhan, Zeynep Çelik Rodrigues, Thaíse S. Vrard, Mathieu Yıldız, Mutlu Zinn, Joel C. Örtel, Sibel Beck, Paul G. Bell, Keaton J. Guo, Zhao Jiang, Chen Kuszlewicz, James S. Kuehn, Charles A. Li, Tanda Lundkvist, Mia S. Pinsonneault, Marc Tayar, Jamie Cunha, Margarida S. Hekker, Saskia Huber, Daniel Miglio, Andrea Monteiro, Mario J.P.F.G. Slumstrup, Ditte Winther, Mark L. Angelou, George Benomar, Othman Bódi, Attila de Moura, Bruno L. Deheuvels, Sébastien Derekas, Aliz Di Mauro, Maria Pia Dupret, Marc-Antoine Jiménez, Antonio Lebreton, Yveline Matthews, Jaymie Nardetto, Nicolas do Nascimento, Jose D. Pereira, Filipe Rodríguez Díaz, Luisa F. Serenelli, Aldo M. Spitoni, Emanuele Stonkutė, Edita Suárez, Juan Carlos Szabó, Robert van Eylen, Vincent Ventura, Rita Verma, Kuldeep Weiss, Achim Wu, Tao Barclay, Thomas Christensen-Dalsgaard, Jørgen Jenkins, Jon M. Kjeldsen, Hans Ricker, George R. Seager, Sara Vanderspek, Roland Department of Physics and Astronomy Aarhus University Ny Munkegade 120 Aarhus C8000 Denmark School of Physics University of New South Wales SydneyNSW2052 Australia School of Physics University of Sydney NSW2006 Australia School of Physics and Astronomy University of Birmingham BirminghamB15 2TT United Kingdom Department of Astronomy Yale University New HaveCT06520 United States Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Rua das Estrelas Porto4150-762 Portugal IRFU CEA Université Paris-Saclay Gif-sur-YvetteF-91191 France AIM CEA CNRS Université Paris-Saclay Université Paris Diderot Sorbonne Paris Cité Gif-sur-YvetteF-91191 France Dept. of Chemistry and Physics Florida Gulf Coast University 10501 FGCU Blvd. S. Fort MyersFL33965 United States Departamento de Física e Astronomia Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre s/n Porto4169-007 Portugal INAF Osservatorio Astrofisico di Catania Via S. Sofia 78 Catania95123 Italy Max Planck Institute for Solar System Research Justus-von-Liebig Weg 3 GöttingenD-37077 Germany Department of Astronomy New Mexico State University P.O. Box 30001 MSC 4500 Las CrucesNM88003-8001 United States Institut für Astrophysik Universität Wien Türkenschanzstrasse 17 Vienna1180 Austria Department of Astronomy Beijing Normal University Beijing100875 China Instituto de Astrofísica de Canarias E-38200 La Laguna Tenerife Spain Departamento de Astrofísica Universidad de La Laguna La Laguna TenerifeE-38206 Spain An der Sternwarte 16 Potsdam14482 Germany LESIA Observatoire de Paris Université PSL CNRS Sorbonne Université Université de Paris Meudon92195 France Department of Astronomy and Space Sciences Science Faculty Ege University Bornova Izmir35100 Turkey Osservatorio Astronomico di Padova – INAF Vicolo dell’Osservatorio 5 PadovaI-35122 Italy Department of Astronomy Ohio State University 140 West 18th Avenue ColumbusOH43210 United S

Since the onset of the ‘space revolution’ of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archaeology investigations. The launch of the NASA TESS mission has enabled seismic-based inferences to go full sky – providing a clear advantage for large ensemble studies of the different Milky Way components. Here we demonstrate its potential for investigating the Galaxy by carrying out the first asteroseismic ensemble study of red giant stars observed by TESS. We use a sample of 25 stars for which we measure their global asteroseimic observables and estimate their fundamental stellar properties, such as radius, mass, and age. Significant improvements are seen in the uncertainties of our estimates when combining seismic observables from TESS with astrometric measurements from the Gaia mission compared to when the seismology and astrometry are applied separately. Specifically, when combined we show that stellar radii can be determined to a precision of a few percent, masses to 5-10% and ages to the 20% level. This is comparable to the precision typically obtained using end-of-mission Kepler data. Copyright © 2019, The Authors. All rights reserved.

关键词： Seismology

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¹²CO J=2-1 and J=3-2 line observations of molecular clouds toward the directions of 59 EGOs in the northern sky

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Chinese Astronomy and Astrophysics 2014年第3期38卷 265-293页

作者： Li, Zhi-Guang He, Jin-Hua Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China University of Chinese Academy of Sciences Beijing 100049 China

In order to investigate the differences between the molecular clouds which are associated with the massive star forming regions and those which are not, we have performed the single-dish simultaneous observations of ¹²CO J=2-1 and J=3-2 lines toward a sample of 59 Spitzer Extended Green objects (EGOs) as the massive star forming regions in the northern sky. Combining our results with the data of the ¹²CO J=1-0 observations toward the same sample EGOs in the literature, we have made the statistical comparisons on the intensities and linewidths of multiple ¹²CO lines between the molecular clouds associated with EGOs (EGO molecular clouds, in brief) and other non-EGO molecular clouds. On this basis, we have discussed the effects of the gas temperature, density, and velocity field distributions on the statistical characteristics of the two kinds of molecular clouds. It is found that both the EGO molecular clouds and non-EGO molecular clouds have similar mass ranges, hence we conclude that for the formation of massive stars, the key-important factor is probably not the total mass of a giant molecular cloud (GMC), but the volume filling factor of the molecular clumps in the GMC (or the compression extent of the molecular gas in the cloud). © 2014.

关键词： Clouds-ISM Formation-ISM ISM Molecules-submillimeter Spectral lines and bands-ISM Stars

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Study on properties of the k - ω model for stellar convection

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Chinese Astronomy and Astrophysics 2014年第4期38卷 413-426页

作者： Zhi-Liang, Guo Yan, Li Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China University of Chinese Academy of Sciences Beijing 100049 China

For applying the k - ω model proposed by Li to the general stellar environment, it is necessary to study the physical meanings of the parameters in this model, in order to set a limit for the range of their values. It is indicated by the study that the variation of the parameter c^l_μ impacts all the Péclet number, kinetic energy, characteristic timescale and characteristic length of turbulent flows. Besides, as the model parameter c^l_μ increases, the damping rate of turbulent kinetic energy in the bottom convective overshoot region can be accelerated evidently. Both the model parameter c^l_μ and the equivalent mixing length parameter α are proportional to the effciency of convective heat transfer in the convection zone, and their logarithms have a linear relation. There is also a linear relation between the logarithms of the model parameter c^l_μ and the damping index θ of turbulent kinetic energy in the convective overshoot region. For the Sun, a group of appropriate model parameters are obtained to be: c^l_μ = 0.004, and α = 1.7. © 2014.

关键词： Convection Methods: numerical Stars: late-type

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The MALATANG Survey: the Lgas − LIR correlation on sub-kiloparsec scale in six nearby star-forming galaxies as traced by HCN J = 4 → 3 and HCO+ J = 4 → 3

arXiv

引用

arXiv 2018年

作者： Tan, Qing-Hua Gao, Yu Zhang, Zhi-Yu Greve, Thomas R. Jiang, Xue-Jian Wilson, Christine D. Yang, Chen-Tao Bemis, Ashley Chung, Aeree Matsushita, Satoki Shi, Yong Ao, Yi-Ping Brinks, Elias Currie, Malcolm J. Davis, Timothy A. de Grijs, Richard Ho, Luis C. Imanishi, Masatoshi Kohno, Kotaro Lee, Bumhyun Parsons, Harriet Rawlings, Mark G. Rigopoulou, Dimitra Rosolowsky, Erik Bulger, Joanna Chen, Hao Chapman, Scott C. Eden, David Gear, Walter K. Gu, Qiu-Sheng He, Jin-Hua Jiao, Qian Liu, Dai-Zhong Liu, Li-Jie Li, Xiao-Hu Michalowski, Michal J. Nguyen-Luong, Quang Qiu, Jian-Jie Smith, Matthew W.L. Violino, Giulio Wang, Jian-Fa Wang, Jun-Feng Wang, Jun-Zhi Yeh, Sherry Zhao, Ying-He Zhu, Ming Purple Mountain Observatory Key Laboratory for Radio Astronomy Chinese Academy of Sciences 8 Yuanhua Road Nanjing210034 China Institute for Astronomy University of Edinburgh Royal Observatory Blackford Hill EdinburghEH9 3HJ United Kingdom ESO Karl-Schwarzschild-Str.2 GarchingD-85748 Germany Department of Physics and Astronomy University College London Gower Street LondonWC1E6BT United Kingdom Department of Physics and Astronomy McMaster University HamiltonONL8S 4M1 Canada Institut d’Astrophysique Spatiale CNRS Univ. Paris-Sud Université Paris-Saclay Bât. 121 Orsay Cedex91405 France European Southern Observatory Alonso de Córdova 3107 Casilla 19001 Vitacura Santiago Chile Department of Astronomy Yonsei University 50 Yonsei-ro Seodaemun-gu Seoul03722 Korea Republic of Academia Sinica Institute of Astronomy and Astrophysics P.O. Box 23-141 Taipei10617 Taiwan School of Astronomy and Space Science Nanjing University Nanjing210093 China National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Centre for Astrophysics Research University of Hertfordshire College Lane HatfieldAL10 9AB United Kingdom RAL Space Rutherford Appleton Laboratory Harwell Campus Didcot OxfordshireOX11 0QX United Kingdom School of Physics and Astronomy Cardiff University Queen’s Buildings The Parade CardiffCF24 3AA United Kingdom Kavli Institute for Astronomy & Astrophysics Department of Astronomy Peking University Yi He Yuan Lu 5 Hai Dian District Beijing100871 China Department of Physics and Astronomy Macquarie University Balaclava Road North RydeNSW2109 Australia International Space Science Institute–Beijing 1 Nanertiao Zhongguancun Hai Dian District Beijing100190 China Institute of Astronomy Graduate School of Science University of Tokyo Osawa Mitaka Tokyo181-0015 Japan Research Center for the Early Universe Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan East Asian Obse

We present HCN J = 4 → 3 and HCO+ J = 4 → 3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2′ × 2′ region at 14′′ (FWHM) resolution (corresponding to linear scales of ∼ 0.2 − 1.0 kpc). The LIR − L′dense relation, where the dense gas is traced by the HCN J = 4 → 3 and the HCO+ J = 4 → 3 emission, measured in our sample of spatially-resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, LIR/L′dense, shows systematic variations with LIR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between LIR/L′dense ratio and the warm-dust temperature gauged by the 70 µm/100 µm flux ratio. We find the luminosity ratios of IR/HCN(4-3) and IR/HCO+(4-3), which can be taken as a proxy for the efficiency of star formation in the dense molecular gas (SFEdense), appears to be nearly independent of the dense-gas fraction (fdense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with fdense when combining our data with that on local (ultra)luminous infrared galaxies and high-z quasars. The mean L′HCN(4−3)/L′HCO+(4−3) line ratio measured for the six targeted galaxies is 0.9±0.6. No significant correlation is found for the L′HCN(4−3)/L′HCO+(4−3) ratio with the SFR as traced by LIR, nor with the warm-dust temperature, for the different populations of galaxies. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

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Mass-transfer in close binary and their companions

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Journal of Physics: Conference Series 2016年第7期728卷

作者： Wenping Liao Shengbang Qian Liying Zhu Linjia Li Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 650216 Kunming P.R. China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O. Box 110 650216 Kunming P. R. China University of the Chinese Academy of Sciences Yuquan Road 19# Shijingshan Block 100049 Beijing P. R. China

Secular and/or cyclical orbital period variations of close binaries can be derived by analyzing the (O-C) diagram. The secular variations are usually explained as mass transfer between components, while the most plausible explanation of the cyclic period changes is the light-travel time effect (LTTE) through the presence of a third body. Mass transfer and additional companions in close binary systems are important for understanding the formation and evolution of the systems. Here, UV light curves of several close binaries based on the Lunar-based Ultraviolet Telescope (LUT) observations are presented and analyzed with the Wilson-Devinney (W-D) method. Then, based on those light-curve solutions and new analysis of the orbital period variations, the multiplicity, geometrical structure and evolution state of targets are discussed.

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A tale of two transients: GW170104 and GRB170105A

arXiv

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arXiv 2017年

作者： Bhalerao, V. Kasliwal, M.M. Bhattacharya, D. Corsi, A. Aarthy, E. Adams, S.M. Blagorodnova, N. Cantwell, T. Cenko, S.B. Fender, R. Frail, D. Itoh, R. Jencson, J. Kawai, N. Kong, A.K.H. Kupfer, T. Kutyrev, A. Mao, J. Mate, S. Mithun, N.P.S. Mooley, K. Perley, D.A. Perrott, Y.C. Quimby, R.M. Rao, A.R. Singer, L.P. Sharma, V. Titterington, D.J. Troja, E. Vadawale, S.V. Vibhute, A. Vedantham, H. Veilleux, S. Department of Physics Indian Institute of Technology Bombay Mumbai400076 India Cahill Center for Astronomy and Astrophysics California Institute of Technology PasadenaCA91125 United States Inter-University Centre for Astronomy and Astrophysics P. O. Bag 4 Ganeshkhind Pune411007 India Department of Physics and Astronomy Texas Tech University Box 1051 LubbockTX79409-1051 United States Physical Research Laboratory Ahmedabad India University of Manchester Alan Turing Building Oxford Road ManchesterM13 9PL United Kingdom Astrophysics Science Division NASA Goddard Space Flight Center 8800 Greenbelt Road GreenbeltMD20771 United States Joint Space-Science Institute University of Maryland College ParkMD20742 United States Centre for Astrophysical Surveys University of Oxford Denys Wilkinson Building Keble Road OxfordOX1 3RH United Kingdom National Radio Astronomy Observatory P.O. Box O SocorroNM87801 United States Department of Physics Tokyo Institute of Technology 2-12-1 Ookayama Meguro-ku Tokyo152-8551 Japan Institute of Astronomy Department of Physics National Tsing Hua University Hsinchu30013 Taiwan Astrophysics Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom Department of Astronomy University of Maryland College ParkMD20742 United States Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan Province650011 China Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Dark Cosmology Centre Niels Bohr Institute University of Copenhagen Juliane Maries Vej 30 København Ø2100 Denmark Department of Astronomy San Diego State University Tata Institute of Fundamental Research Homi Bhabha Road Mumbai India Astrophysics Group Cavendish Laboratory 19 J. J. Thomson Avenue CambridgeCB3 0HE United Kingdom Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Bei

We present multi-wavelength follow-up campaigns by the AstroSat-CZTI and GROWTH collaborations to search for an electromagnetic counterpart to the gravitational wave event GW170104. At the time of the GW170104 trigger, the AstroSat CZTI field-of-view covered 50.3% of the sky localization. We do not detect any hard X-ray (>100 keV) signal at this time, and place an upper limit of ≈ 4.5×10−7 erg cm−2 s−1 for a 1 s timescale. Separately, the ATLAS survey reported a rapidly fading optical source dubbed ATLAS17aeu in the error circle of GW170104. Our panchromatic investigation of ATLAS17aeu shows that it is the afterglow of an unrelated long, soft GRB 170105A, with only a fortuitous spatial coincidence with GW170104. We then discuss the properties of this transient in the context of standard long GRB afterglow models. Copyright © 2017, The Authors. All rights reserved.

关键词： Gravitational effects

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