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Title: KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA

Abstract

We present the ALMA Band 3 and Band 6 results of {sup 12}CO(2-1), {sup 13}CO(2-1), H30 α recombination line, free–free emission around 98 GHz, and the dust thermal emission around 230 GHz toward the N159 East Giant Molecular Cloud (N159E) in the Large Magellanic Cloud (LMC). LMC is the nearest active high-mass star-forming face-on galaxy at a distance of 50 kpc and is the best target for studing high-mass star formation. ALMA observations show that N159E is the complex of filamentary clouds with the width and length of ∼1 pc and several parsecs. The total molecular mass is 0.92 × 10{sup 5} M {sub ⊙} from the {sup 13}CO(2-1) intensity. N159E harbors the well-known Papillon Nebula, a compact high-excitation H ii region. We found that a YSO associated with the Papillon Nebula has the mass of 35 M {sub ⊙} and is located at the intersection of three filamentary clouds. It indicates that the formation of the high-mass YSO was induced by the collision of filamentary clouds. Fukui et al. reported a similar kinematic structure toward two YSOs in the N159 West region, which are the other YSOs that have the mass of ≳35 M {sub ⊙}. This suggests thatmore » the collision of filamentary clouds is a primary mechanism of high-mass star formation. We found a small molecular hole around the YSO in Papillon Nebula with a sub-parsec scale. It is filled by free–free and H30 α emission. The temperature of the molecular gas around the hole reaches ∼80 K. It indicates that this YSO has just started the distruction of parental molecular cloud.« less

Authors:
; ;  [1]; ; ;  [2]; ;  [3];  [4];  [5]; ; ; ; ;  [6];  [7];  [8]; ;  [9];  [10] more »; « less
  1. Chile Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Science, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  2. Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan)
  3. The Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States)
  4. NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)
  5. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)
  6. Department of Physics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan)
  7. Nobeyama Radio Observatory, 462-2 Nobeyama Minamimaki-mura, Minamisaku-gun, Nagano 384-1305 (Japan)
  8. Division of Theoretical Astronomy, National Astronomical Observatory (Japan)
  9. Laboratoire AIM, CEA, Universite Paris VII, IRFU/Service d’Astrophysique, Bat. 709, F-91191 Gif-sur-Yvette (France)
  10. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
Publication Date:
OSTI Identifier:
22664005
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 835; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON 12; CARBON 13; CARBON MONOXIDE; COLLISIONS; DUSTS; EMISSION; EXCITATION; FASTENERS; GHZ RANGE; MAGELLANIC CLOUDS; MASS; MOLECULES; NEBULAE; RECOMBINATION; STARS

Citation Formats

Saigo, Kazuya, Harada, Ryohei, Kawamura, Akiko, Onishi, Toshikazu, Tokuda, Kazuki, Morioka, Yuuki, Nayak, Omnarayani, Meixner, Margaret, Sewiło, Marta, Indebetouw, Remy, Torii, Kazufumi, Ohama, Akio, Hattori, Yusuke, Yamamoto, Hiroaki, Tachihara, Kengo, Minamidani, Tetsuhiro, Inoue, Tsuyoshi, Madden, Suzanne, Lebouteiller, Vianney, Galametz, Maud, and and others. KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA. United States: N. p., 2017. Web. doi:10.3847/1538-4357/835/1/108.
Saigo, Kazuya, Harada, Ryohei, Kawamura, Akiko, Onishi, Toshikazu, Tokuda, Kazuki, Morioka, Yuuki, Nayak, Omnarayani, Meixner, Margaret, Sewiło, Marta, Indebetouw, Remy, Torii, Kazufumi, Ohama, Akio, Hattori, Yusuke, Yamamoto, Hiroaki, Tachihara, Kengo, Minamidani, Tetsuhiro, Inoue, Tsuyoshi, Madden, Suzanne, Lebouteiller, Vianney, Galametz, Maud, & and others. KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA. United States. doi:10.3847/1538-4357/835/1/108.
Saigo, Kazuya, Harada, Ryohei, Kawamura, Akiko, Onishi, Toshikazu, Tokuda, Kazuki, Morioka, Yuuki, Nayak, Omnarayani, Meixner, Margaret, Sewiło, Marta, Indebetouw, Remy, Torii, Kazufumi, Ohama, Akio, Hattori, Yusuke, Yamamoto, Hiroaki, Tachihara, Kengo, Minamidani, Tetsuhiro, Inoue, Tsuyoshi, Madden, Suzanne, Lebouteiller, Vianney, Galametz, Maud, and and others. Fri . "KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA". United States. doi:10.3847/1538-4357/835/1/108.
@article{osti_22664005,
title = {KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA},
author = {Saigo, Kazuya and Harada, Ryohei and Kawamura, Akiko and Onishi, Toshikazu and Tokuda, Kazuki and Morioka, Yuuki and Nayak, Omnarayani and Meixner, Margaret and Sewiło, Marta and Indebetouw, Remy and Torii, Kazufumi and Ohama, Akio and Hattori, Yusuke and Yamamoto, Hiroaki and Tachihara, Kengo and Minamidani, Tetsuhiro and Inoue, Tsuyoshi and Madden, Suzanne and Lebouteiller, Vianney and Galametz, Maud and and others},
abstractNote = {We present the ALMA Band 3 and Band 6 results of {sup 12}CO(2-1), {sup 13}CO(2-1), H30 α recombination line, free–free emission around 98 GHz, and the dust thermal emission around 230 GHz toward the N159 East Giant Molecular Cloud (N159E) in the Large Magellanic Cloud (LMC). LMC is the nearest active high-mass star-forming face-on galaxy at a distance of 50 kpc and is the best target for studing high-mass star formation. ALMA observations show that N159E is the complex of filamentary clouds with the width and length of ∼1 pc and several parsecs. The total molecular mass is 0.92 × 10{sup 5} M {sub ⊙} from the {sup 13}CO(2-1) intensity. N159E harbors the well-known Papillon Nebula, a compact high-excitation H ii region. We found that a YSO associated with the Papillon Nebula has the mass of 35 M {sub ⊙} and is located at the intersection of three filamentary clouds. It indicates that the formation of the high-mass YSO was induced by the collision of filamentary clouds. Fukui et al. reported a similar kinematic structure toward two YSOs in the N159 West region, which are the other YSOs that have the mass of ≳35 M {sub ⊙}. This suggests that the collision of filamentary clouds is a primary mechanism of high-mass star formation. We found a small molecular hole around the YSO in Papillon Nebula with a sub-parsec scale. It is filled by free–free and H30 α emission. The temperature of the molecular gas around the hole reaches ∼80 K. It indicates that this YSO has just started the distruction of parental molecular cloud.},
doi = {10.3847/1538-4357/835/1/108},
journal = {Astrophysical Journal},
number = 1,
volume = 835,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2017},
month = {Fri Jan 20 00:00:00 EST 2017}
}
  • We report the first detection of a hot molecular core outside our Galaxy based on radio observations with ALMA toward a high-mass young stellar object (YSO) in a nearby low metallicity galaxy, the Large Magellanic Cloud (LMC). Molecular emission lines of CO, C{sup 17}O, HCO{sup +}, H{sup 13}CO{sup +}, H{sub 2}CO, NO, SiO, H{sub 2}CS, {sup 33}SO, {sup 32}SO{sub 2}, {sup 34}SO{sub 2}, and {sup 33}SO{sub 2} are detected from a compact region (∼0.1 pc) associated with a high-mass YSO, ST11. The temperature of molecular gas is estimated to be higher than 100 K based on rotation diagram analysis ofmore » SO{sub 2} and {sup 34}SO{sub 2} lines. The compact source size, warm gas temperature, high density, and rich molecular lines around a high-mass protostar suggest that ST11 is associated with a hot molecular core. We find that the molecular abundances of the LMC hot core are significantly different from those of Galactic hot cores. The abundances of CH{sub 3}OH, H{sub 2}CO, and HNCO are remarkably lower compared to Galactic hot cores by at least 1–3 orders of magnitude. We suggest that these abundances are characterized by the deficiency of molecules whose formation requires the hydrogenation of CO on grain surfaces. In contrast, NO shows a high abundance in ST11 despite the notably low abundance of nitrogen in the LMC. A multitude of SO{sub 2} and its isotopologue line detections in ST11 imply that SO{sub 2} can be a key molecular tracer of hot core chemistry in metal-poor environments. Furthermore, we find molecular outflows around the hot core, which is the second detection of an extragalactic protostellar outflow. In this paper, we discuss the physical and chemical characteristics of a hot molecular core in the low metallicity environment.« less
  • We analyze the conditions for detection of CO(1-0) emission in the Large Magellanic Cloud, using the recently completed second NANTEN CO survey. In particular, we investigate correlations between CO integrated intensity and H I integrated intensity, peak brightness temperature, and line width at a resolution of 2.'6 ({approx}40 pc). We find that significant H I column density (exceeding {approx}10{sup 21} cm{sup -2}) and peak brightness temperature (exceeding {approx}20 K) are necessary but not sufficient conditions for CO detection, with many regions of strong H I emission not associated with molecular clouds. The large scatter in CO intensities for a givenmore » H I intensity persists even when averaging on scales of >200 pc, indicating that the scatter is not solely due to local conversion of H I into H{sub 2} near GMCs. We focus on two possibilities to account for this scatter: either there exist spatial variations in the I(CO) to N(H{sub 2}) conversion factor, or a significant fraction of the atomic gas is not involved in molecular cloud formation. A weak tendency for CO emission to be suppressed for large H I linewidths supports the second hypothesis, insofar as large linewidths may be indicative of warm H I, and calls into question the likelihood of forming molecular clouds from colliding H I flows. We also find that the ratio of molecular to atomic gas shows no significant correlation (or anticorrelation) with the stellar surface density, though a correlation with midplane hydrostatic pressure P{sub h} is found when the data are binned in P{sub h} . The latter correlation largely reflects the increasing likelihood of CO detection at high H I column density.« less
  • We compare the CO (J = 1-0) and H I emission in the Large Magellanic Cloud in three dimensions, i.e., including a velocity axis in addition to the two spatial axes, with the aim of elucidating the physical connection between giant molecular clouds (GMCs) and their surrounding H I gas. The CO J = 1-0 data set is from the second NANTEN CO survey and the H I data set is from the merged Australia Telescope Compact Array (ATCA) and Parkes Telescope surveys. The major findings of our analysis are as follows: (1) GMCs are associated with an envelope ofmore » H I emission, (2) in GMCs [average CO intensity] propor to [average H I intensity]{sup 1.1+}-{sup 0.1}, and (3) the H I intensity tends to increase with the star formation activity within GMCs, from Type I to Type III. An analysis of the H I envelopes associated with GMCs shows that their average line width is 14 km s{sup -1} and the mean density in the envelope is 10 cm{sup -3}. We argue that the H I envelopes are gravitationally bound by GMCs. These findings are consistent with a continual increase in the mass of GMCs via H I accretion at an accretion rate of 0.05 M{sub sun} yr{sup -1} over a timescale of 10 Myr. The growth of GMCs is terminated via dissipative ionization and/or stellar-wind disruption in the final stage of GMC evolution.« less
  • We present the properties of an extensive sample of molecular clouds in the Large Magellanic Cloud (LMC) mapped at 11 pc resolution in the CO(1-0) line. Targets were chosen based on a limiting CO flux and peak brightness as measured by the NANTEN survey. The observations were conducted with the ATNF Mopra Telescope as part of the Magellanic Mopra Assessment. We identify clouds as regions of connected CO emission and find that the distributions of cloud sizes, fluxes, and masses are sensitive to the choice of decomposition parameters. In all cases, however, the luminosity function of CO clouds is steepermore » than dN/dL{proportional_to}L{sup -2}, suggesting that a substantial fraction of mass is in low-mass clouds. A correlation between size and linewidth, while apparent for the largest emission structures, breaks down when those structures are decomposed into smaller structures. We argue that the correlation between virial mass and CO luminosity is the result of comparing two covariant quantities, with the correlation appearing tighter on larger scales where a size-linewidth relation holds. The virial parameter (the ratio of a cloud's kinetic to self-gravitational energy) shows a wide range of values and exhibits no clear trends with the CO luminosity or the likelihood of hosting young stellar object (YSO) candidates, casting further doubt on the assumption of virialization for molecular clouds in the LMC. Higher CO luminosity increases the likelihood of a cloud harboring a YSO candidate, and more luminous YSOs are more likely to be coincident with detectable CO emission, confirming the close link between giant molecular clouds and massive star formation.« less
  • Archival Spitzer Infrared Array Camera (IRAC) and MIPS observations of the Large Magellanic Cloud (LMC) have been used to search for young stellar objects (YSOs). We have carried out independent aperture photometry of these data and merged the results from different passbands to produce a photometric catalog. To verify our methodology we have also analyzed the data from the SAGE and SWIRE Legacy programs; our photometric measurements are in general agreement with the photometry released by these programs. A detailed completeness analysis for our photometric catalog of the LMC shows that the 90% completeness limits are, on average, 16.0, 15.0,more » 14.3, 13.1, and 9.2 mag at 3.6, 4.5, 5.8, 8.0, and 24 {mu}m, respectively. Using our mid-infrared photometric catalogs and two simple selection criteria, [4.5]-[8.0]>2.0 to exclude normal and evolved stars and [8.0]>14-([4.5]-[8.0]) to exclude background galaxies, we have identified a sample of 2910 sources in the LMC that could potentially be YSOs. We then used the Spitzer observations complemented by optical and near-infrared data to carefully assess the nature of each source. To do so we simultaneously considered multiwavelength images and photometry to assess the source morphology, spectral energy distribution (SED) from the optical through the mid-infrared wavelengths, and the surrounding interstellar environment to determine the most likely nature of each source. From this examination of the initial sample, we suggest that 1172 sources are most likely YSOs. We have also identified 1075 probable background galaxies, consistent with the expected number estimated from the SWIRE survey. Spitzer IRS observations of 269 of the brightest YSOs from our sample have confirmed that {approx}>95% are indeed YSOs. An examination of color-color and color-magnitude diagrams shows no simple criteria in color-magnitude space that can unambiguously separate the LMC YSOs from all asymptotic giant branch (AGB)/post-AGB stars, planetary nebulae, and background galaxies. A comprehensive search for YSOs in the LMC has also been carried out by the SAGE team and reported by Whitney et al. There are three major differences between these two searches. (1) In the common region of color-magnitude space, {approx}850 of our 1172 probable YSOs are missed in the SAGE YSO catalog because their conservative point-source identification criteria have excluded YSOs superposed on complex stellar and interstellar environments. (2) About 20%-30% of the YSOs identified by the SAGE team are sources we classify as background galaxies. (3) The SAGE YSO catalog identifies YSO in parts of color-magnitude space that we excluded and thus contains more evolved or fainter YSOs missed by our analysis. The shortcomings and strengths of both these YSO catalogs should be considered prior to statistical studies of star formation in the LMC. Finally, the mid-infrared luminosity functions in the IRAC bands of our most likely YSO candidates in the LMC can be well described by N(L) {proportional_to} L {sup -1}, which is consistent with the Salpeter initial mass function if a mass-luminosity relation of L {proportional_to} M {sup 2.4} is adopted.« less