FIRST DETECTION OF A SUBKILOPARSEC SCALE MOLECULAR OUTFLOW IN THE STARBURST GALAXY NGC 3628

Journal Article · Sun Jun 10 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/752/1/38· OSTI ID:22037103

Tsai, An-Li ^[1]; Matsushita, Satoki ^[2]; Kong, Albert K. H. ^[3]; Matsumoto, Hironori ^[4]; Kohno, Kotaro ^[5]

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1. Graduate Institute of Astronomy, National Central University, No. 300, Jhongda Rd., Jhongli, Taoyuan 32001, Taiwan (China)
2. Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)
3. Institute of Astronomy and Department of Physics, National Tsing Hua University, No. 101, Sec. , Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)
4. Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan)
5. Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)

We successfully detected a molecular outflow with a scale of 370-450 pc in the central region of the starburst galaxy NGC 3628 through deep CO(1-0) observations by using the Nobeyama Millimeter Array (NMA). The mass of the outflowing molecular gas is {approx}2.8 Multiplication-Sign 10{sup 7} M{sub Sun }, and the outflow velocity is {approx}90 {+-} 10 km s{sup -1}. The expansion timescale of the outflow is 3.3-6.8 Myr, and the molecular gas mass flow rate is 4.1-8.5 M{sub Sun} yr{sup -1}. It requires mechanical energy of (1.8-2.8) Multiplication-Sign 10{sup 54} erg to create this sub-kpc scale molecular outflow. In order to understand the evolution of the molecular outflow, we compare the physical properties between the molecular outflow observed from our NMA CO(1-0) data and the plasma gas from the soft X-ray emission of the Chandra X-ray Observatory archival data. We found that the distribution between the molecular outflow and the strong plasma outflow seems to be in a similar region. In this region, the ram pressure and the thermal pressure of the plasma outflow are 10{sup -(8-10)} dyn cm{sup -2}, and the thermal pressure of molecular outflow is 10{sup -(11-13)} dyn cm{sup -2}. This implies that the molecular outflow is still expanding outward. The molecular gas consumption timescale is estimated as 17-27 Myr, and the total starburst timescale is 20-34 Myr. The evolutionary parameter is 0.11-0.25, suggesting that the starburst activity in NGC 3628 is still in a young stage.

• OSTI ID: 22037103
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 752; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
COMPARATIVE EVALUATIONS
DETECTION
EVOLUTION
FLOW RATE
GALAXIES
MASS
PHOTON EMISSION
PLASMA
SOFT X RADIATION
SPATIAL DISTRIBUTION