The nature of the nuclear sources in M82 and NGC 253

Rieke, G. H.; Lebofsky, M. J.; Thompson, Rodger I.; Low, F. J.; Tokunaga, A. T.

doi:10.1086/157954

Cited by 431 publications

(349 citation statements)

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“…The basic properties of the nuclear starburst are [24]: Bolometric luminosity > 5.0×10 10 L ⊙ , absolute K magnitude < −22.5, ionising radiation L Lyc > 10 54 photons/s, total mass in the starburst < 2.5 × 10 8 M ⊙ , CO index > 0.21 and supernova rate ≈ 0.1 yr −1 . Rieke et al [31,32] have pioneered the detailed modelling of this starburst galaxy, and have come repeatedly to the conclusion that stars with masses below a few M ⊙ form much less often in M 82 than in the solar neighbourhood. The argument for a top heavy IMF is basically that the infrared brightness -tracing the bolometric luminosity -is too high for the (dynamically measured) stellar mass, if one assumes a IMF similar to the field star IMF of Scalo [37].…”

Section: Starburst Galaxiesmentioning

confidence: 99%

Evidence in Favour of IMF Variations

Eisenhauer

2001

Starburst Galaxies: Near and Far

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Abstract. The stellar initial mass function (IMF) determines the relative number of stars born at a given mass. Despite the tremendous effort to establish a universal IMF, the astronomical literature offers a wealth of diverse evidence for IMF variations. This review was prepared for a controversial debate at the conference "Starbursts -Near and Far" at Ringberg Castle, 2000, and gives a one-sided portrayal in favour of IMF variations. I will summarise the empirical evidence that the IMF varies with time, with environment, and for all stellar masses. While I see no obvious systematic trend in most regions of our Galaxy, there is at least an indication that the IMF is biased towards more massive stars in the early universe and in starbursts.

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Section: Starburst Galaxiesmentioning

confidence: 99%

Evidence in Favour of IMF Variations

Eisenhauer

2001

Starburst Galaxies: Near and Far

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“…He also suggested that extinction corrections in M82 made by others were too high, and this made it appear like M82 had a truncated IMF when really it didn't. Satyapal (1995) indeed found low extinction in M82 from Paβ/Brγ, which gave A V = 2 − 12 mag compared to 25 mag in Rieke et al (1980). Satyapal then got a K-band luminosity 3 times lower than Rieke et al, and saw no need for IMF truncation.…”

Section: Introduction: History Of Starburst Imfsmentioning

confidence: 85%

“…The nearby starburst galaxy, M82, was one of the best cases. Rieke et al (1980Rieke et al ( , 1993 modeled M82's gas mass, luminous star mass, rotation curve mass, 2.2 µm flux, Lyman continuum flux, CO index for supergiants, and the Brα/Brγ ratio, giving an extinction A V = 25 mag. They concluded that only the usual IMF models with lower mass limits M L > 3 − 6 M ⊙ worked.…”

Section: Introduction: History Of Starburst Imfsmentioning

confidence: 99%

The Initial Mass Function in Starbursts

Elmegreen

2005

Starbursts

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The history of the IMF in starburst regions is reviewed. The IMFs are no longer believed to be top-heavy, although some superstar clusters, whether in starburst regions or not, could be. Introduction: History of Starburst IMFsEarly starburst observations suggested the luminous mass from young massive stars is comparable to the dynamical mass from the rotation curve (see reviews in Telesco 1988; Scalo 1990; Zinnecker 1996; Leitherer 1999). This implied there was a deficit in low mass stars. The nearby starburst galaxy, M82, was one of the best cases. Rieke et al. (1980Rieke et al. ( , 1993 modeled M82's gas mass, luminous star mass, rotation curve mass, 2.2 µm flux, Lyman continuum flux, CO index for supergiants, and the Brα/Brγ ratio, giving an extinction A V = 25 mag. They concluded that only the usual IMF models with lower mass limits M L > 3 − 6 M ⊙ worked. Kronberg et al. (1985) used the Lyman continuum flux from radio emission in M82 to determine the star formation rate, and used the total gas mass combined with an efficiency estimate to conclude that the IMF is top-heavy compared to the Miller & Scalo (1979) IMF. Bernlohr (1992 fit the same M82 properties as Rieke et al., plus the heavy element abundance and FIR line ratios, and concluded that either the IMF slope is shallower than the Scalo (1986) IMF by 1, or there is a lower mass cutoff greater than 1.5-2

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“…M 82 is regarded as the archetypical starburst galaxy (Rieke et al 1980). Its distance of only 3.9 Mpc (Sakai & Madore 1999) makes M 82 an excellent laboratory for studying the relevant physical processes connected with starburst activity in detail.…”

Section: Introductionmentioning

confidence: 99%

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.

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The nature of the nuclear sources in M82 and NGC 253

Cited by 431 publications

References 0 publications

Evidence in Favour of IMF Variations

Evidence in Favour of IMF Variations

The Initial Mass Function in Starbursts

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

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