Morphology of the nuclear region of M82 at 2.2 microns

Dietz, Richard; Smith, J.; Hackwell, J. A.; Gehrz, R. D.; Grasdalen, G. L.

doi:10.1086/114057

Cited by 33 publications

(47 citation statements)

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“…Early studies of the distribution of the molecular gas in M 82 unveiled a double-lobed circumnuclear distribution of CO which was interpreted as a molecular torus with a depletion of molecular gas in the central region (Nakai et al 1987). More recent highresolution studies by Shen &Lo (1995) using BIMA andNeininger et al (1998) using the IRAM interferometer at Plateau de Bure (PdBI) showed a third molecular peak 65 pc west of the 2.2 µm nucleus (Dietz et al 1986). Using these high-resolution CO maps Weiß et al (1999) identified an expanding superbubble in the molecular gas of M 82 which links the triple peak CO distribution and its disturbed velocity field to the prominent outflow visible in Hα and X-rays.…”

Section: Send Offprint Requests Tomentioning

confidence: 99%

The effect of violent star formation on the state of the molecular gas in M 82

Weiß

Neininger

Hüttemeister

et al. 2001

A&A

184

152

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Abstract. We present the results of a high angular resolution, multi-transition analysis of the molecular gas in M 82. The analysis is based on the two lowest transitions of 12 CO and the ground transition of the rare isotopes 13 CO and C 18 O measured with the PdBI, the BIMA array and the IRAM 30 m telescope. In order to address the question of how the intrinsic molecular cloud properties are influenced by massive star formation we have carried out radiative transfer calculations based on the observed CO line ratios. The calculations suggest that the kinetic temperature of the molecular gas is high in regions with strong star formation and drops towards the outer molecular lobes with less ongoing star formation. The location of the highest kinetic temperature is coincident with that of the mid infrared (MIR) peaks which trace emission from hot dust. The hot gas is associated with low H2 densities while the cold gas in the outer molecular lobes has high H2 densities. We find that CO intensities do not trace H2 column densities well. Most of the molecular gas is distributed in a double-lobed distribution which surrounds the starburst. A detailed analysis of the conversion factor from CO intensity to H2 column density shows that XCO depends on the excitation conditions. We find XCO ∼ T −1 kin n(H2) 1/2 , as expected for virialized clouds.

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Section: Send Offprint Requests Tomentioning

confidence: 99%

The effect of violent star formation on the state of the molecular gas in M 82

Weiß

Neininger

Hüttemeister

et al. 2001

A&A

184

152

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“…In the molecular gas images, the value for the color scale is indicated on the top of each figure; the plus sign indicates the position of the galactic nucleus determined from the peak of the strongest 2.2 mm source (Lester et al 1990). (a) X-ray image (contours; Bregman et al 1995) overlaid on the Ha image (gray scale; Shopbell & Bland-Hawthorn 1998) indicate, respectively, the central positions of the 2.2 mm secondary peak (Dietz et al 1986) and the X-ray point source observed with ROSAT (Stevens et al 1999) that corresponds to the ASCA hard X-ray variable source position (Matsumoto & Tsuru 1999). We also indicate the recently observed Chandra X-ray variable source (open circle; Matsumoto et al 2000) whose radius corresponds to its position uncertainty.…”

Section: Expanding Molecular Superbubblementioning

confidence: 99%

Formation of a Massive Black Hole at the Center of the Superbubble in M82

Matsushita

Kawabe

Matsumoto

et al. 2000

The Astrophysical Journal

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We performed CO (1-0), CO (1-0), and HCN (1-0) interferometric observations of the central region 12 13 (about 450 pc in radius) of M82 with the Nobeyama Millimeter Array and have successfully imaged a molecular superbubble and spurs. The center of the superbubble is clearly shifted from the nucleus by 140 pc. This position is close to that of the massive black hole (BH) of տ460 M and the 2.2 mm secondary peak (a luminous , supergiant-dominated cluster), which strongly suggests that these objects may be related to the formation of the superbubble. Consideration of star formation in the cluster based on the infrared data indicates that (1) the energy release from supernovae can account for the kinetic energy of the superbubble, (2) the total mass of stellar-mass BHs available for building up the massive BH may be much higher than 460 M , and (3) it is possible to form , the middle-mass BH of 10 2 -10 3 M within the timescale of the superbubble. We suggest that the massive BH , was produced and is growing in the intense starburst region.

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“…The central pointing was centred on the 2.2µm nucleus at α = 09 h 55 m 51 s .94, δ = 69 • 40 47.14 (J2000.0) (Dietz et al 1986). The other pointings were shifted with respect to the central position by (α, δ) = (−30 , −8 ), (−20 , −6 ), (−10 , −4 ), (10 , 4 ), (20 , 8 ), (30 , 10 ) which ensured sufficient overlap of the observed fields at 230 GHz.…”

Section: Pdbi Observationsmentioning

confidence: 99%

“…The overall morphology of both images is very similar to the 12 CO(J = 1 → 0) distribution published by Shen & Lo (1995) and the 13 CO(J = 1 → 0) distribution published by Neininger et al (1998). It shows a triple peak morphology of which the two outer lobes have been interpreted as the edge of a central molecular toroid (Nakai et al 1987, Shen & Lo 1995 and a weaker central peak located 65 pc west of the M 82's centre (2.2µm peak; Dietz et al 1986). The two outer lobes have a projected separation of 410 pc (26 ).…”

Section: Co Morphology and Kinematicsmentioning

confidence: 99%

“…Early studies of the distribution of the molecular gas in M 82 unveiled a double-lobed circumnuclear distribution of CO which was interpreted as a molecular torus with a depletion of molecular gas in the central region (Nakai et al 1987). More recent highresolution studies by Shen & Lo (1995) using BIMA and Neininger et al (1998) using the IRAM interferometer at Plateau de Bure (PdBI) showed a third molecular peak 65 pc west of the 2.2µm nucleus (Dietz et al 1986). Using these high-resolution CO maps Weiß et al (1999) identified an expanding superbubble in the molecular gas of M 82 which linked the triple peak CO distribution and its disturbed velocity field to the prominent outflow visible in Hα and X-rays.…”

Section: Introductionmentioning

confidence: 96%

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The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

Weiß

Neininger

Hüttemeister

et al. 2001

The Evolution of Galaxies

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Abstract. We present the results of a high angular resolution, multi-transition analysis of the molecular gas in M 82. The analysis is based on the two lowest transitions of 12 CO and the ground transition of the rare isotopes 13 CO and C 18 O measured with the PdBI, the BIMA array and the IRAM 30m telescope. In order to address the question of how the intrinsic molecular cloud properties are influenced by massive star formation we have carried out radiative transfer calculations based on the observed CO line ratios. The calculations suggest that the kinetic temperature of the molecular gas is high in regions with strong star formation and drops towards the outer molecular lobes with less ongoing star formation. The location of the highest kinetic temperature is coincident with that of the mid infrared (MIR) peaks which trace emission from hot dust. The hot gas is associated with low H 2 densities while the cold gas in the outer molecular lobes has high H 2 densities. We find that CO intensities do not trace H 2 column densities well. Most of the molecular gas is distributed in a double-lobed distribution which surrounds the starburst. A detailed analysis of the conversion factor from CO intensity to H 2 column density shows that X CO depends on the excitation conditions. We find X CO ∼ T −1 kin n(H 2 ) 1/2 , as expected for virialized clouds.

show abstract

Morphology of the nuclear region of M82 at 2.2 microns

Cited by 33 publications

References 0 publications

The effect of violent star formation on the state of the molecular gas in M 82

The effect of violent star formation on the state of the molecular gas in M 82

Formation of a Massive Black Hole at the Center of the Superbubble in M82

The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

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