Molecular Gas in M82: Resolving the Outflow and Streamers

By F. Walter, A. Weiss, N. Scoville. 2002

232 citations recorded by the source corpus.

We present a high-resolution (3.″6, 70 pc) 12CO (J = 1 → 0) mosaic of the molecular gas in M82 covering an area of 2.′5 × 3.′5 (2.8 × 3.9 kpc) obtained with the Owens Valley Radio Observatory millimeter interferometer. The observations reveal the presence of huge amounts of molecular gas (>70% of the total molecular mass, Mtot ≈ 1.3 × 109 M☉) outside the central 1 kpc disk. Molecular streamers are detected in and below M82's disk out to distances from the center of ~1.7 kpc. Some of these streamers are well correlated with optical absorption features; they form the basis of some of the prominent tidal H I features around M82. This provides evidence that the molecular gas within M82's optical disk is disrupted by the interaction with M81. Molecular gas is found in M82's outflow/halo, reaching distances up to 1.2 kpc below the plane; CO line splitting has been detected for the first time in the outflow. The maximum outflow velocity is ~230 km s-1; we derive an opening angle of ~55° for the molecular outflow cone. The total amount of gas in the outflow is greater than 3 × 108 M☉, and its kinetic energy is of order 1055 ergs, about 1% of the estimated total mechanical energy input of M82's starburst. Our study implies that extreme starburst environments can move significant amounts of molecular gas into a galaxy's halo (and even to the intergalactic medium).

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/4746e116e4278bcdfe165d545542bca24ccb8552

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Citations in the corpus

• Massive molecular outflows and evidence for AGN feedback from CO observations (2013, methodology): “We adopt the CO integrated flux of S CO = 7240 Jy km s−1, estimated by Walter et al. (2002) for the outflow north and south of the molecular disk.”
• The Spectral Energy Distribution of CO lines in M82 (2005, background): “1), close to the value determined by us for the central molecular disk (Walter et al. 2002).”
• Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind (2011, background): “In the past years, few studies have targeted outflowing molecular gas (e.g. Nakai et al. 1987; Garcı́a-Burillo et al. 2001; Walter et al. 2002; Sakamoto et al. 2006) but recently evidence is mounting for massive molecular outflows in AGNs and starburst galaxies (Sakamoto et al. 2010; Feruglio et…”
• The mass function of young star clusters in spiral galaxies (2008, background): “The starburst in M 82 is driving a superwind with outflow velocities in excess of 100 km s−1, carrying a significant fraction of the molecular gas in the system (Walter et al. 2002), again showing that a large amount of energy is being injected into the interstellar gas.”
• THE INTERSTELLAR MEDIUM IN DISTANT STAR-FORMING GALAXIES: TURBULENT PRESSURE, FRAGMENTATION, AND CLOUD SCALING RELATIONS IN A DENSE GAS DISK AT z = 2.3 (2011, background): “…emission compared to highJ lines has recently been reported for a number of high-redshift sub-millimetre galaxies (Ivison et al. 2011; Riechers et al. 2011a,b) in addition to low redshift starbursts (e.g. Papadopoulos & Seaquist 1998; Mao et al. 2000; Weiß et al. 2001, 2005; Walter et al. 2002).”
• MASSIVE MOLECULAR OUTFLOWS AND NEGATIVE FEEDBACK IN ULIRGs OBSERVED BY HERSCHEL-PACS (2011, background): “Few detections of molecular outflows have been reported so far (e.g. Baan et al. 1989, Walter et al. 2002, Sakamoto et al. 2009).”
• Cool Gas in High-Redshift Galaxies (2013, background): “Direct evidence for feedback has been seen in nearby galaxies, including outflows seen in OH far– IR lines, molecular emission lines, optical lines, and atomic fine structure lines (e.g., in the case of M 82: Strickland & Heckman 2009, Walter et al. 2002, Martin et al. 1998).”
• EVIDENCE FOR UBIQUITOUS COLLIMATED GALACTIC-SCALE OUTFLOWS ALONG THE STAR-FORMING SEQUENCE AT z ∼ 0.5 (2013, background): “…provided unequivocal evidence for a collimated (and specifically bipolar) outflow morphology around starburst galaxies in the local universe (e.g., Walter et al. 2002; Westmoquette et al. 2008; Strickland & Heckman 2009), and the detection of higher-velocity Na I absorption toward more face-on…”
• Highly-excited CO emission in APM 08279+5255 at z = 3.9 (2007, result): “E.g. a molecular reservoir similar to that seen around M 82’s starburst disk (Walter et al. 2002) or the spiral arms surrounding the nucleus of NGC 1068 (e.g. Schinnerer et al. 2000) would remain undetected as its contribution to the observed CO line intensities would be negligible.”
• DISCOVERY OF AN ACTIVE GALACTIC NUCLEUS DRIVEN MOLECULAR OUTFLOW IN THE LOCAL EARLY-TYPE GALAXY NGC 1266 (2011, methodology): “There is a small sample of galaxies that have been shown to exhibit molecular outflows: M82, Arp 220, Mrk 231 and M51.”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, background): “…with optical emission lines, soft and hard X-ray emission, blueshifted interstellar absorption lines, outflowing molecular gas, or a nonthermal radio continuum halo (Heckman et al. 1990; Lehnert & Heckman 1996; Walter et al. 2002; Heckman 2003; Veilleux et al. 2005; Strickland & Heckman 2009).”
• TRACING OUTFLOWS AND ACCRETION: A BIMODAL AZIMUTHAL DEPENDENCE OF Mg ii ABSORPTION (2012, unknown): “Our estimated outflow opening angle is consistent with other published values determined using different techniques (e.g., Walter et al. 2002; Martin et al. 2012).”