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12 results on '"Naslim Neelamkodan"'

1. An Unbiased CO Survey Toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. II. CO Cloud Catalog

Author

Takahiro Ohno, Kazuki Tokuda, Ayu Konishi, Takeru Matsumoto, Marta Sewiło, Hiroshi Kondo, Hidetoshi Sano, Kisetsu Tsuge, Sarolta Zahorecz, Nao Goto, Naslim Neelamkodan, Tony Wong, Hajime Fukushima, Tatsuya Takekoshi, Kazuyuki Muraoka, Akiko Kawamura, Kengo Tachihara, Yasuo Fukui, and Toshikazu Onishi

Subjects
Local Group, Small Magellanic Cloud, Molecular clouds, Star formation, Interstellar medium, Young stellar objects, Astrophysics, QB460-466
Abstract

The nature of molecular clouds and their statistical behavior in subsolar metallicity environments are not fully explored yet. We analyzed data from an unbiased CO ( J = 2–1) survey at the spatial resolution of ∼2 pc in the northern region of the Small Magellanic Cloud with the Atacama Compact Array to characterize the CO cloud properties. A cloud-decomposition analysis identified 426 spatially/velocity-independent CO clouds and their substructures. Based on the cross-matching with known infrared catalogs by Spitzer and Herschel, more than 90% CO clouds show spatial correlations with point sources. We investigated the basic properties of the CO clouds and found that the radius–velocity linewidth ( R – σ _v ) relation follows the Milky Way-like power-law exponent, but the intercept is ∼1.5 times lower than that in the Milky Way. The mass functions ( dN / dM ) of the CO luminosity and virial mass are characterized by an exponent of ∼1.7, which is consistent with previously reported values in the Large Magellanic Cloud and in the Milky Way.

Published
2023
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2. Physical and Chemical Conditions in the N113 Star-Forming Region in the Low-Metallicity Large Magellanic Cloud

Author

Jonathon Noswitz, Marta Sewilo, Molly Finn, Remy Indebetouw, Jennifer Wiseman, CH Chen, Kazuki Tokuda, Toshikazu Onishi, Joana M Oliveira, Akiko Kawamura, Yasuo Fukui, Naslim Neelamkodan, Tony Wong, and Lynn Carlson

Subjects
Astrophysics
Abstract

The Large Magellanic Cloud (LMC) is the nearest (~50 kpc) star-forming galaxy characterized by a low metallicity (Z~0.3-0.5 Z⨀) similar to galaxies during the early phases of their assembly. As a result, star formation studies in the LMC provide a stepping stone to understanding star formation at earlier epochs of the universe where these processes cannot be directly observed. N113 is one of the most prominent star-forming regions in the LMC hosting one of the most massive giant molecular clouds.N113 is small enough to be imaged in its entirety, but large enough to showcase many important phenomena such as multiple generations of stars, stellar feedback, and different environments. We present our findings from an investigation of the early stages of star formation in the N113 region using the Atacama Large Millimeter/submillimeter Array (ALMA)molecular line data probing a wide density range: 12CO, 13CO, and C18O (2-1), 13COand C18O (1-0), HCN (1-0), HCO+ (1-0), H13CN (1-0) and (3-2), H13CO+ (1-0) and (3-2), CS (2-1) and (5-4), as well as 1.3 mm and 3 mm continuum. We used the Python package quick clump to identify molecular clumps. We utilized the multiline non-LTE fitting tool based on models from RADEX developed by Finn et al. (2021, ApJ, 917, 106)to construct the CO, HCN, HCO+, and CS temperature and column density, and the H2density maps of N113. We constructed a catalog of molecular clumps including their physical properties, chemical abundances, sizes, velocities, and velocity dispersions. To establish the evolutionary status of the clumps, their positions were compared with previously identified young stellar objects (YSOs) from the Spitzer/SAGE and Herschel/HERITAGE surveys, as well as water and OH masers. We compared the properties of the clumps in N113 to those in the Galaxy and other regions in the LMC to assess the impact of the environment (e.g., metallicity, stellar feedback) on the star formation process.

Published
2022

3. A Study of Photoionized Gas in Two H װ Regions of the N44 Complex in the LMC Using MUSE Observations

Author

Susmita Barman, Naslim Neelamkodan, Suzanne C. Madden, Marta Sewilo, Francisca Kemper, Kazuki Tokuda, Soma Sanyal, and Toshikazu Onishi

Subjects
Astrophysics
Abstract

We use the optical integral field observations with Multi-Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope, together with CLOUDY photoionization models, to study ionization structure and physical conditions of two luminous H װ regions in the N44 star-forming complex of the Large Magellanic Cloud. The spectral maps of various emission lines reveal a stratified ionization geometry in N44 D1. The spatial distribution of [O ו] λ6300 emission in N44 D1 indicates a partially covered ionization front at the outer boundary of the H װ region. These observations reveal that N44 D1 is a blister H װ region. The [O ו] λ6300 emission in N44 C does not provide a well-defined ionization front at the boundary, while patches of [S װ] λ6717 and [O ו] λ6300 emission bars are found in the interior. The results of spatially resolved MUSE spectra are tested with the photoionization models for the first time in these H װ regions. A spherically symmetric ionization-bounded model with a partial covering factor, which is appropriate for a blister H װ region, can well reproduce the observed geometry and most of the diagnostic line ratios in N44 D1. Similarly, in N44 C we apply a low-density and optically thin model based on the observational signatures. Our modeling results show that the ionization structure and physical conditions of N44 D1 are mainly determined by the radiation from an O5 V star. However, local X-rays, possibly from supernovae or stellar wind, play a key role. In N44 C, the main contribution is from three ionizing stars.

Published
2022
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4. An Unbiased CO Survey toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. I. Overview: CO Cloud Distributions

Author

Kazuki Tokuda, Hiroshi Kondo, Takahiro Ohno, Ayu Konishi, Hidetoshi Sano, Kisetsu Tsuge, Sarolta Zahorecz, Nao Goto, Naslim Neelamkodan, Tony Wong, Marta Sewiło, Hajime Fukushima, Tatsuya Takekoshi, Kazuyuki Muraoka, Akiko Kawamura, Kengo Tachihara, Yasuo Fukui, and Toshikazu Onishi

Subjects
Astrophysics, Astronomy
Abstract

We have analyzed the data from a large-scale CO survey toward the northern region of the Small Magellanic Cloud (SMC) obtained with the Atacama Compact Array (ACA) stand-alone mode of ALMA. The primary aim of this study is to comprehensively understand the behavior of CO as an H2 tracer in a low-metallicity environment (Z ∼ 0.2 Zꙩ). The total number of mosaic fields is ∼8000, which results in a field coverage of 0.26 sq.deg (∼2.9 ×10^(5) sq.pc), corresponding to ∼10% of the area of the galaxy. The sensitive ∼2 pc resolution observations reveal the detailed structure of the molecular clouds previously detected in the single-dish NANTEN survey. We have detected a number of compact CO clouds within lower H2 column density (∼10^(20) per sq.cm) regions whose angular scale is similar to the ACA beam size. Most of the clouds in this survey also show peak brightness temperature as low as <1 K, which for optically thick CO emission implies an emission size much smaller than the beam size, leading to beam dilution. The comparison between an available estimation of the total molecular material traced by thermal dust emission and the present CO survey demonstrates that more than ∼90% of H(2) gas cannot be traced by the low-J CO emission. Our processed data cubes and 2D images are publicly available.

Published
2021
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5. PDRs4All: A JWST Early Release Science Program on Radiative Feedback from Massive Stars

Author

Olivier Berné, Émilie Habart, Els Peeters, Alain Abergel, Edwin A. Bergin, Jeronimo Bernard-Salas, Emeric Bron, Jan Cami, Emmanuel Dartois, Asunción Fuente, Javier R. Goicoechea, Karl D. Gordon, Yoko Okada, Takashi Onaka, Massimo Robberto, Markus Röllig, Alexander G. G. M. Tielens, Sílvia Vicente, Mark G. Wolfire, Felipe Alarcón, C. Boersma, Amélie Canin, Ryan Chown, Daniel Dicken, David Languignon, Romane Le Gal, Marc W. Pound, Boris Trahin, Thomas Simmer, Ameek Sidhu, Dries Van De Putte, Sara Cuadrado, Claire Guilloteau, Alexandros Maragkoudakis, Bethany R. Schefter, Thiébaut Schirmer, Stéphanie Cazaux, Isabel Aleman, Louis Allamandola, Rebecca Auchettl, Giuseppe Antonio Baratta, Salma Bejaoui, Partha P. Bera, Goranka Bilalbegović, John H. Black, Francois Boulanger, Jordy Bouwman, Bernhard Brandl, Philippe Brechignac, Sandra Brünken, Andrew Burkhardt, Alessandra Candian, Jose Cernicharo, Marin Chabot, Shubhadip Chakraborty, Jason Champion, Sean W. J. Colgan, Ilsa R. Cooke, Audrey Coutens, Nick L. J. Cox, Karine Demyk, Jennifer Donovan Meyer, Cécile Engrand, Sacha Foschino, Pedro García-Lario, Lisseth Gavilan, Maryvonne Gerin, Marie Godard, Carl A. Gottlieb, Pierre Guillard, Antoine Gusdorf, Patrick Hartigan, Jinhua He, Eric Herbst, Liv Hornekaer, Cornelia Jäger, Eduardo Janot-Pacheco, Christine Joblin, Michael Kaufman, Francisca Kemper, Sarah Kendrew, Maria S. Kirsanova, Pamela Klaassen, Collin Knight, Sun Kwok, Álvaro Labiano, Thomas S.-Y. Lai, Timothy J. Lee, Bertrand Lefloch, Franck Le Petit, Aigen Li, Hendrik Linz, Cameron J. Mackie, Suzanne C. Madden, Joëlle Mascetti, Brett A. McGuire, Pablo Merino, Elisabetta R. Micelotta, Karl Misselt, Jon A. Morse, Giacomo Mulas, Naslim Neelamkodan, Ryou Ohsawa, Alain Omont, Roberta Paladini, Maria Elisabetta Palumbo, Amit Pathak, Yvonne J. Pendleton, Annemieke Petrignani, Thomas Pino, Elena Puga, Naseem Rangwala, Mathias Rapacioli, Alessandra Ricca, Julia Roman-Duval, Joseph Roser, Evelyne Roueff, Gaël Rouillé, Farid Salama, Dinalva A. Sales, Karin Sandstrom, Peter Sarre, Ella Sciamma-O’Brien, Kris Sellgren, Matthew J. Shannon, Sachindev S. Shenoy, David Teyssier, Richard D. Thomas, Aditya Togi, Laurent Verstraete, Adolf N. Witt, Alwyn Wootten, Nathalie Ysard, Henning Zettergren, Yong Zhang, Ziwei E. Zhang, Junfeng Zhen, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), University of Western Ontario (UWO), Carl Sagan Center, SETI Institute, University of Michigan [Ann Arbor], University of Michigan System, Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universiteit Gent = Ghent University (UGENT), Space Telescope Science Institute (STSci), Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, Meisei University, The University of Tokyo (UTokyo), Leiden Observatory [Leiden], Universiteit Leiden, Johns Hopkins University (JHU), Instituto de Astrofísica e Ciências do Espaço (IASTRO), University of Maryland [College Park], University of Maryland System, NASA Ames Research Center (ARC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Institut National Polytechnique (Toulouse) (Toulouse INP), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Delft University of Technology (TU Delft), Universidade Federal de Itajubá, Bay Area Environmental Research Institute (BAER), Australian Synchrotron [Clayton], INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), University of Zagreb, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Colorado [Boulder], Institute for Molecules and Materials [Nijmegen], Radboud University [Nijmegen], Wellesley College, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), University of British Columbia (UBC), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Rice University [Houston], Yunnan Observatories, Chinese Academy of Sciences [Changchun Branch] (CAS), Universidad de Chile = University of Chile [Santiago] (UCHILE), University of Virginia, Aarhus University [Aarhus], Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Instituto de Astronomia, Geofísica e Ciências Atmosféricas [São Paulo] (IAG), Universidade de São Paulo = University of São Paulo (USP), San Jose State University [San Jose] (SJSU), European Southern Observatory (ESO), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, Institute of Astronomy of the Russian Academy of Sciences (INASAN), Russian Academy of Sciences [Moscow] (RAS), UK Astronomy Technology Centre (UK ATC), Science and Technology Facilities Council (STFC), Telespazio, Services par satellites, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), University of Missouri [Columbia] (Mizzou), University of Missouri System, Max Planck Institute for Astronomy (MPIA), CAS Key Laboratory of Crust–Mantle Materials and Environments [Hefei], School of Earth and Space Sciences [Hefei], University of Science and Technology of China [Hefei] (USTC)-University of Science and Technology of China [Hefei] (USTC)-Chinese Academy of Sciences [Beijing] (CAS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), University of California [Berkeley] (UC Berkeley), University of California (UC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), Instituto de Ciencia de Materiales de Madrid (ICMM), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Steward Observatory, University of Arizona, INAF - Osservatorio Astronomico di Cagliari (OAC), United Arab Emirates University (UAEU), National Astronomical Observatory of Japan (NAOJ), Banaras Hindu University [Varanasi] (BHU), University of Amsterdam [Amsterdam] (UvA), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), University of California [San Diego] (UC San Diego), University of Nottingham, UK (UON), Ohio State University [Columbus] (OSU), Space Science Institute [Boulder] (SSI), Stockholm University, Texas State University, Ritter Astrophysical Research Center, University of Toledo, National Sun Yat-Sen University (NSYSU), Star and Planet Formation Laboratory, ITA, USA, GBR, FRA, DEU, ESP, AUS, BEL, BRA, CHL, TWN, HRV, DNK, JPN, IND, NLD, PRT, CHN, RUS, SWE, National Aeronautics and Space Administration (US), University of Maryland, University of Michigan, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Natural Sciences and Engineering Research Council of Canada, Ministerio de Ciencia e Innovación (España), German Research Foundation, Japan Society for the Promotion of Science, San José State University Research Foundation, Berné, Olivier, Habart, Émilie, Peeters, Els, Abergel, Alain, Bergin, Edwin A., Bernard-Salas, Jeronimo, Bron, Emeric, Cami, Jan, Dartois, Emmanuel, Fuente, Asunción, Goicoechea, Javier R., Gordon, Karl D., Okada, Yoko, Onaka, Takashi, Robberto, Massimo, Röllig, Markus, Tielens, Alexander G.G.M., Vicente, Sílvia, Wolfire, Mark G., Alarcón, Felipe, Boersma, C., Canin, Amélie, Chown, Ryan, Dicken, Daniel, Le Gal, Romane, Pound, Marc W., Trahin, Boris, Sidhu, Ameek, Van De Putte, Dries, Cuadrado, Sara, Guilloteau, Claire, Maragkoudakis, Alexandros, Schefter, Bethany R., Schirmer, Thiébaut, Aleman, Isabel, Allamandola, Louis, Auchettl, Rebecca, Antonio Baratta, Giuseppe, Bejaoui, Salma, Bera, Partha P., Bilalbegović, Goranka, Black, John H., Boulanger, Francois, Bouwman, Jordy, Brandl, Bernhard, Brünken, Sandra, Burkhardt, Andrew, Candian, Alessandra, Cernicharo, José, Chakraborty, Shubhadip, Champion, Jason, Colgan, Sean W.J., Cooke, Ilsa R., Coutens, Audrey, Cox, Nick L.J., Demyk, Karine, Donovan Meyer, Jennifer, Engrand, Cécile, Foschino, Sacha, Gavilan, Lisseth, Gerin, Maryvonne, Godard, Marie, Gottlieb, Carl A., Guillard, Pierre, Gusdorf, Antoine, Hartigan, Patrick, He, Jinhua, Herbst, Eric, Hornekaer, Liv, Janot-Pacheco, Eduardo, Joblin, Christine, Kaufman, Michael, Kemper, Francisca, Kendrew, Sarah, Kirsanova, Maria S., Klaassen, Pamela, Knight, Collin, Kwok, Sun, Labiano, Álvaro, Lai, Thomas S.Y., Lee, Timothy J., Lefloch, Bertrand, Le Petit, Franck, Li, Aigen, Linz, Hendrik, MacKie, Cameron J., Madden, Suzanne C., Mascetti, Joëlle, McGuire, Brett A., Merino, Pablo, Micelotta, Elisabetta R., Morse, Jon A., Molecular Spectroscopy (HIMS, FNWI), and HIMS (FNWI)

Subjects
Gaseous Nebulae, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, FELIX Infrared and Terahertz Spectroscopy, Star Forming Regions, Astrophysics - Astrophysics of Galaxies, Infrared Telescopes, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, [INFO]Computer Science [cs], Photodissociation Regions, Astrophysics::Earth and Planetary Astrophysics, Polycyclic Aromatic Hydrocarbons, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], James Webb Space Telescope (JWST), Photo-Dissociation Regions (PDRs), Massive stars, Orion Bar, MIRI, NIRSpec, NIRCam, Astrophysics::Galaxy Astrophysics
Abstract

22 pags., 8 figs., 1 tab., Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1-3 to the present day. The dominant feedback processes can be probed by observations of the Photo-Dissociation Regions (PDRs) where the far-ultraviolet photons of massive stars create warm regions of gas and dust in the neutral atomic and molecular gas. PDR emission provides a unique tool to study in detail the physical and chemical processes that are relevant for most of the mass in inter-and circumstellar media including diffuse clouds, proto-planetary disks, and molecular cloud surfaces, globules, planetary nebulae, and star-forming regions. PDR emission dominates the infrared (IR) spectra of star-forming galaxies. Most of the Galactic and extragalactic observations obtained with the James Webb Space Telescope (JWST) will therefore arise in PDR emission. In this paper we present an Early Release Science program using the MIRI, NIRSpec, and NIRCam instruments dedicated to the observations of an emblematic and nearby PDR: the Orion Bar. These early JWST observations will provide template data sets designed to identify key PDR characteristics in JWST observations. These data will serve to benchmark PDR models and extend them into the JWST era. We also present the Science-Enabling products that we will provide to the community. These template data sets and Science-Enabling products will guide the preparation of future proposals on star-forming regions in our Galaxy and beyond and will facilitate data analysis and interpretation of forthcoming JWST observations., Support for JWST-ERS program ID 1288 was provided through grants from the STScI under NASA contract NAS5-03127 to STScI (K.G., D.V.D.P., M.R.), Univ. of Maryland (M.W., M.P.), Univ. of Michigan (E.B., F.A.), and Univ. of Toledo (T.S.-Y.L.). O.B. and E.H. are supported by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES, and through APR grants 6315 and 6410 provided by CNES. E. P. and J.C. acknowledge support from the National Science and Engineering Council of Canada (NSERC) Discovery Grant program (RGPIN-2020-06434 and RGPIN-2021-04197 respectively). E.P. acknowledges support from a Western Strategic Support Accelerator Grant (ROLA ID 0000050636). J.R.G. and S.C. thank the Spanish MCINN for funding support under grant PID2019-106110GB-I00. Work by M.R. and Y.O. is carried out within the Collaborative Research Centre 956, subproject C1, funded by the Deutsche Forschungsgemeinschaft (DFG)—project ID 184018867. T.O. acknowledges support from JSPS Bilateral Program, grant No. 120219939. M.P. and M.W. acknowledge support from NASA Astrophysics Data Analysis Program award #80NSSC19K0573. C.B. is grateful for an appointment at NASA Ames Research Center through the San José State University Research Foundation (NNX17AJ88A) and acknowledges support from the Internal Scientist Funding Model (ISFM) Directed Work Package at NASA Ames titled: “Laboratory Astrophysics—The NASA Ames PAH IR Spectroscopic Database.”

Published
2022

6. A study of photoionized gas in two HII regions of the N44 complex in the LMC using MUSE observations

Author

Susmita Barman, Naslim Neelamkodan, Suzanne C. Madden, Marta Sewilo, Francisca Kemper, Kazuki Tokuda, Soma Sanyal, and Toshikazu Onishi

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We use the optical integral field observations with Multi-Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope, together with CLOUDY photoionization models to study ionization structure and physical conditions of two luminous HII regions in N44 star-forming complex of the Large Magellanic Cloud. The spectral maps of various emission lines reveal a stratified ionization geometry in N44 D1. The spatial distribution of [O I] 6300A emission in N44 D1 indicates a partially covered ionization front at the outer boundary of the H II region. These observations reveal that N44 D1 is a Blister HII region. The [O I] 6300A emission in N44 C does not provide a well-defined ionization front at the boundary, while patches of [S II] 6717 A and [O I] 6300A emission bars are found in the interior. The results of spatially resolved MUSE spectra are tested with the photoionization models for the first time in these HII regions. A spherically symmetric ionization-bounded model with a partial covering factor, which is appropriate for a Blister HII region can well reproduce the observed geometry and most of the diagnostic line ratios in N44 D1. Similarly, in N44 C we apply a low density and optically thin model based on the observational signatures. Our modeling results show that the ionization structure and physical conditions of N44 D1 are mainly determined by the radiation from an O5 V star. However, local X-rays, possibly from supernovae or stellar wind, play a key role. In N44 C, the main contribution is from three ionizing stars., Accepted for publication in ApJ

Published
2022

7. The First Detection of a Protostellar CO Outflow in the Small Magellanic Cloud with ALMA

Author

Kazuki Tokuda, Sarolta Zahorecz, Yuri Kunitoshi, Kosuke Higashino, Kei E. I. Tanaka, Ayu Konishi, Taisei Suzuki, Naoya Kitano, Naoto Harada, Takashi Shimonishi, Naslim Neelamkodan, Yasuo Fukui, Akiko Kawamura, Toshikazu Onishi, and Masahiro N. Machida

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

Protostellar outflows are one of the most outstanding features of star formation. Observational studies over the last several decades have successfully demonstrated that outflows are ubiquitously associated with low- and high-mass protostars in the solar-metallicity Galactic conditions. However, the environmental dependence of protostellar outflow properties is still poorly understood, particularly in the low-metallicity regime. Here we report the first detection of a molecular outflow in the Small Magellanic Cloud with 0.2 $Z_{\odot}$, using Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of 0.1 pc toward the massive protostar Y246. The bipolar outflow is nicely illustrated by high-velocity wings of CO(3-2) emission at $\gtrsim$15 km s$^{-1}$. The evaluated properties of the outflow (momentum, mechanical force, etc.) are consistent with those of the Galactic counterparts. Our results suggest that the molecular outflows, i.e., the guidepost of the disk accretion at the small scale, might be universally associated with protostars across the metallicity range of $\sim$0.2-1 $Z_{\odot}$., Comment: 7 pages, 2 figures, Accepted for publication in ApJL

Published
2022

8. RADIO OBSERVATIONS OF THE NEUTRON STAR X-RAY BINARY CIRCINUS X-1: CLUES ON THE ONSET OF RADIO EMISSION AND JET FORMATION

Author

Dr. Aquib Moin, Dr. Naslim Neelamkodan, Saleh Ilyasi, Batool Ahmad Essa, Dr. Aquib Moin, Dr. Naslim Neelamkodan, and Saleh Ilyasi, Batool Ahmad Essa

Abstract

Circinus X-1 is a Neutron-Star X-ray Binary System which features strong and variable radio emission. This emission is triggered as a result of the interaction between neutron star and its companion as they approach periastron. Radio observations of Circinus X-1 have not been carried out over the past 7 years. Here are the results of the radio observation and monitoring campaign on Circinus X-1 with the Australia Telescope Compact Array (ATCA) – Australia, at centimeter wavelengths (5.5 and 9 GHz). The radio behavior of Circinus X-1 has been monitored over two of its orbits (16.6 days each) to probe its current radio brightness as a function of its orbit. An investigation on whether there is any correlation between the observed radio emission and the estimated accretion rates, and what difference do the orbital phases make in terms of the system’s observed behavior has been made.

Published
2020

9. An Unbiased CO Survey toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. I. Overview: CO Cloud Distributions

Author

Ayu Konishi, Hidetoshi Sano, Nao Goto, Tony Wong, Kisetsu Tsuge, Toshikazu Onishi, Kazuki Tokuda, Yasuo Fukui, Akiko Kawamura, Takahiro Ohno, Hajime Fukushima, Sarolta Zahorecz, Hiroshi Kondo, Tatsuya Takekoshi, Naslim Neelamkodan, Marta Sewilo, Kengo Tachihara, and Kazuyuki Muraoka

Subjects
Physics, Field (physics), Molecular cloud, Resolution (electron density), FOS: Physical sciences, Astronomy and Astrophysics, Scale (descriptive set theory), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Brightness temperature, Thermal, Small Magellanic Cloud, Astrophysics::Galaxy Astrophysics
Abstract

We have analyzed the data from a large-scale CO survey toward the northern region of the Small Magellanic Cloud (SMC) obtained with the Atacama Compact Array (ACA) stand-alone mode of ALMA. The primary aim of this study is to comprehensively understand the behavior of CO as an H$_2$ tracer in a low-metallicity environment ($Z\sim0.2~Z_{\odot}$). The total number of mosaic fields is $\sim$8000, which results in a field coverage of 0.26$~$degree$^{2}$ ($\sim$2.9 $\times$10$^{5}$$~$pc$^2$), corresponding to $\sim$10$\%$ area of the galaxy. The sensitive $\sim$2$~$pc resolution observations reveal the detailed structure of the molecular clouds previously detected in the single-dish NANTEN survey. We have detected a number of compact CO clouds within lower H$_2$ column density ($\sim$10$^{20}$$~$cm$^{-2}$) regions whose angular scale is similar to the ACA beam size. Most of the clouds in this survey also show peak brightness temperature as low as $, Comment: 20 pages, 13 figures, 2 tables (including appendix). Accepted for publication in ApJ

Published
2021

10. Subaru and Salt Spectroscopy of Chemically Peculiar Hot Subdwarfs

Author

Roy Ostensen, C. Simon Jeffery, Naslim Neelamkodan, Steven M. Crawford, and Vincent M. Woolf

Subjects
chemistry.chemical_classification, 010308 nuclear & particles physics, Chemistry, Astronomy, Inorganic chemistry, Salt (chemistry), Astronomy and Astrophysics, QB1-991, 01 natural sciences, stars: chemically peculiar, stars: subdwarfs, Space and Planetary Science, 0103 physical sciences, Spectroscopy, 010303 astronomy & astrophysics
Abstract

The majority of hot subdwarfs lie on or close to the helium main-sequence. Many have hydrogen-rich surfaces, but a substantial fraction of the hotter subdwarfs have hydrogen-depleted or hydrogen-deficient surfaces. Amongst the former, three were known to show extraordinary overabundances of heavy elements including zirconium and lead. Using Subaru/HDS,we commenced a high-resolution survey of hydrogen-depleted subdwarfs to discover new members of the class. UVO 0825+15, was found to exhibit strong lead lines, to be an intrinsic variable in K2 field 5, and to have a relatively high space motion. Two other lead-rich subdwarfs have been found in the Subaru sample. A much wider survey is in progress using SALT/HRS. Discoveries so far include one extreme helium star similar to V652 Her, and an intermediate helium star with possible comparison to HD144941. Analyses of the hotter and more compact members of the sample are continuing.

Published
2017

11. ALMA Reveals a Cloud–Cloud Collision that Triggers Star Formation in the Small Magellanic Cloud

Author

Hiroshi Kondo, Hidetoshi Sano, Naslim Neelamkodan, Kazuki Tokuda, Susmita Barman, and Toshikazu Onishi

Subjects
Interstellar medium, Physics, Space and Planetary Science, business.industry, Star formation, Astronomy, Astronomy and Astrophysics, Cloud computing, Small Magellanic Cloud, business, Collision
Abstract

We present the results of Atacama Large Millimeter/submillimeter Array observations in 12CO(1–0) emission at 0.58 × 0.52 pc2 resolution toward the brightest H ii region N66 of the Small Magellanic Cloud (SMC). The 12CO(1–0) emission toward the north of N66 reveals clumpy filaments with multiple velocity components. Our analysis shows that a blueshifted filament at a velocity range of 154.4–158.6 km s−1 interacts with a redshifted filament at a velocity of 158.0–161.8 km s−1. A third velocity component at a velocity range of 161–165.0 km s−1 constitutes hub-filaments. An intermediate-mass young stellar object (YSO) and a young pre-main-sequence star cluster have hitherto been reported in the intersection of these filaments. We find a V-shape distribution in the position–velocity diagram at the intersection of two filaments. This indicates the physical association of those filaments due to a cloud–cloud collision. We determine the collision timescale ∼0.2 Myr using the relative velocity (∼5.1 km s−1) and displacement (∼1.1 pc) of those interacting filaments. These results suggest that the event occurred about 0.2 Myr ago and triggered the star formation, possibly an intermediate-mass YSO. We report the first observational evidence for a cloud–cloud collision that triggers star formation in N66N of the low metallicity ∼0.2 Z ⊙ galaxy, the SMC, with similar kinematics as in N159W-South and N159E of the Large Magellanic Cloud.

Published
2021

12. Dust and Gas in diffuse interstellar medium of the Large Magellanic Cloud

Author

Sacha Hony, Naslim Neelamkodan, Ji Yeon Seok, Karl D. Gordon, Caroline Bot, Hiroyuki Hirashita, Yao-Lun Yang, Oscar Morata, Jean-Philippe Bernard, Annie Hughes, Ciska Kemper, William T. Reach, and Suzanne C. Madden

Subjects
Physics, Interstellar medium, Astronomy, Large Magellanic Cloud
Published
2014

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