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Title: The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120–5453

Abstract

We present new Atacama Large Millimeter/submillimeter Array Band 7 (∼340 GHz) observations of the dense gas tracers HCN, HCO{sup +}, and CS in the local, single-nucleus, ultraluminous infrared galaxy IRAS 13120–5453. We find centrally enhanced HCN (4–3) emission, relative to HCO{sup +} (4–3), but do not find evidence for radiative pumping of HCN. Considering the size of the starburst (0.5 kpc) and the estimated supernovae rate of ∼1.2 yr{sup −1}, the high HCN/HCO{sup +} ratio can be explained by an enhanced HCN abundance as a result of mechanical heating by the supernovae, though the active galactic nucleus and winds may also contribute additional mechanical heating. The starburst size implies a high Σ{sub IR} of 4.7 × 10{sup 12} L {sub ⊙} kpc{sup −2}, slightly below predictions of radiation-pressure limited starbursts. The HCN line profile has low-level wings, which we tentatively interpret as evidence for outflowing dense molecular gas. However, the dense molecular outflow seen in the HCN line wings is unlikely to escape the Galaxy and is destined to return to the nucleus and fuel future star formation. We also present modeling of Herschel observations of the H{sub 2}O lines and find a nuclear dust temperature of ∼40 K. IRASmore » 13120–5453 has a lower dust temperature and Σ{sub IR} than is inferred for the systems termed “compact obscured nuclei (CONs)” (such as Arp 220 and Mrk 231). If IRAS 13120–5453 has undergone a CON phase, we are likely witnessing it at a time when the feedback has already inflated the nuclear ISM and diluted star formation in the starburst/active galactic nucleus core.« less

Authors:
;  [1]; ; ; ;  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10];  [11]
  1. Instituto de Astrofśica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)
  2. Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 94 Onsala (Sweden)
  3. Universidad de Alcalá, Departamento de Física y Matemáticas, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain)
  4. Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
  5. Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA, 91125 (United States)
  6. Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States)
  7. Observatorio de Madrid, OAN-IGN, Alfonso XII, 3, E-28014-Madrid (Spain)
  8. Institute of Astronomy, School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
  9. Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, 10617, Taipei, Taiwan (China)
  10. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  11. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
Publication Date:
OSTI Identifier:
22663149
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 835; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPACTS; DUSTS; EMISSION; FEEDBACK; FORECASTING; GALAXIES; HEATING; HYDROCYANIC ACID; INTERACTIONS; NUCLEI; RADIATION PRESSURE; SIMULATION; STELLAR WINDS; SUPERNOVAE; WATER

Citation Formats

Privon, G. C., Treister, E., Aalto, S., Falstad, N., Muller, S., Costagliola, F., González-Alfonso, E., Sliwa, K., Armus, L., Evans, A. S., Garcia-Burillo, S., Izumi, T., Sakamoto, K., Werf, P. van der, and Chu, J. K.. The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120–5453. United States: N. p., 2017. Web. doi:10.3847/1538-4357/835/2/213.
Privon, G. C., Treister, E., Aalto, S., Falstad, N., Muller, S., Costagliola, F., González-Alfonso, E., Sliwa, K., Armus, L., Evans, A. S., Garcia-Burillo, S., Izumi, T., Sakamoto, K., Werf, P. van der, & Chu, J. K.. The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120–5453. United States. doi:10.3847/1538-4357/835/2/213.
Privon, G. C., Treister, E., Aalto, S., Falstad, N., Muller, S., Costagliola, F., González-Alfonso, E., Sliwa, K., Armus, L., Evans, A. S., Garcia-Burillo, S., Izumi, T., Sakamoto, K., Werf, P. van der, and Chu, J. K.. Wed . "The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120–5453". United States. doi:10.3847/1538-4357/835/2/213.
@article{osti_22663149,
title = {The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120–5453},
author = {Privon, G. C. and Treister, E. and Aalto, S. and Falstad, N. and Muller, S. and Costagliola, F. and González-Alfonso, E. and Sliwa, K. and Armus, L. and Evans, A. S. and Garcia-Burillo, S. and Izumi, T. and Sakamoto, K. and Werf, P. van der and Chu, J. K.},
abstractNote = {We present new Atacama Large Millimeter/submillimeter Array Band 7 (∼340 GHz) observations of the dense gas tracers HCN, HCO{sup +}, and CS in the local, single-nucleus, ultraluminous infrared galaxy IRAS 13120–5453. We find centrally enhanced HCN (4–3) emission, relative to HCO{sup +} (4–3), but do not find evidence for radiative pumping of HCN. Considering the size of the starburst (0.5 kpc) and the estimated supernovae rate of ∼1.2 yr{sup −1}, the high HCN/HCO{sup +} ratio can be explained by an enhanced HCN abundance as a result of mechanical heating by the supernovae, though the active galactic nucleus and winds may also contribute additional mechanical heating. The starburst size implies a high Σ{sub IR} of 4.7 × 10{sup 12} L {sub ⊙} kpc{sup −2}, slightly below predictions of radiation-pressure limited starbursts. The HCN line profile has low-level wings, which we tentatively interpret as evidence for outflowing dense molecular gas. However, the dense molecular outflow seen in the HCN line wings is unlikely to escape the Galaxy and is destined to return to the nucleus and fuel future star formation. We also present modeling of Herschel observations of the H{sub 2}O lines and find a nuclear dust temperature of ∼40 K. IRAS 13120–5453 has a lower dust temperature and Σ{sub IR} than is inferred for the systems termed “compact obscured nuclei (CONs)” (such as Arp 220 and Mrk 231). If IRAS 13120–5453 has undergone a CON phase, we are likely witnessing it at a time when the feedback has already inflated the nuclear ISM and diluted star formation in the starburst/active galactic nucleus core.},
doi = {10.3847/1538-4357/835/2/213},
journal = {Astrophysical Journal},
number = 2,
volume = 835,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}