Infrared mapping of M82 - A starburst in an edge-on barred galaxy

Telesco, C. M.; Campins, H.; Joy, M.; Dietz, Kurtis L.; Decher, R.

doi:10.1086/169744

Cited by 79 publications

(122 citation statements)

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“…The distributions observed in our PAH maps and for the PAH 3.29 µm feature by Normand et al (1995) and Satyapal et al (1995) at ≈ 1 ′′ resolution are consistent with each other. Our 15 µm continuum map and the 19.2 µm image of Telesco et al (1991) are similar. Maps of the N -band (10.8 µm) and 11.8 − 13.0 µm emission generated from the ISOCAM data cubes agree well with those of Telesco et al (1991) and Telesco & Gezari (1992) within the regions covered by the latter two images.…”

supporting

confidence: 54%

ISOCAM view of the starburst galaxies M 82, NGC 253 and NGC 1808

Schreiber

Sauvage

Charmandaris

et al. 2003

A&A

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Abstract. We present results of mid-infrared λ = 5.0 − 16.5 µm spectrophotometric imaging of the starburst galaxies M 82, NGC 253, and NGC 1808 from the ISOCAM instrument on board the Infrared Space Observatory. The mid-infrared spectra of the three galaxies are very similar in terms of features present. The λ > ∼ 11 µm continuum attributed to very small dust grains (VSGs) exhibits a large spread in intensity relative to the shortwavelength emission. We find that the 15 µm dust continuum flux density correlates well with the fine-structure [Ar ii] 6.99 µm line flux and thus provides a good quantitative indicator of the level of star formation activity. By contrast, the λ = 5 − 11 µm region dominated by emission from polycyclic aromatic hydrocarbons (PAHs) has a nearly invariant shape. Variations in the relative intensities of the PAH features are nevertheless observed, at the 20% − 100% level. We illustrate extinction effects on the shape of the mid-infrared spectrum of obscured starbursts, emphasizing the differences depending on the applicable extinction law and the consequences for the interpretation of PAH ratios and extinction estimates. The relative spatial distributions of the PAH, VSG, and [Ar ii] 6.99 µm emission between the three galaxies exhibit remarkable differences. The < ∼ 1 kpc size of the midinfrared source is much smaller than the optical extent of our sample galaxies and 70% − 100% of the IRAS 12 µm flux is recovered within the ISOCAM ≤ 1.5 arcmin 2 field of view, indicating that the nuclear starburst dominates the total mid-infrared emission while diffuse light from quiescent disk star formation contributes little.

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supporting

confidence: 54%

ISOCAM view of the starburst galaxies M 82, NGC 253 and NGC 1808

Schreiber

Sauvage

Charmandaris

et al. 2003

A&A

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“…However, there is intriguing evidence that starburst activity is closely linked to the slope of the rotation curve. For example, the starburst galaxy M82 has vigorous star formation in the rigidly rotating part and weak star formation beyond the turnover point of the rotation curve (Telesco et al 1991). Kenney et al (1993) also found that the starburst region in NGC 3504 corresponds to the linearly rising portion of the rotation curve.…”

Section: Application To Inner Galaxiesmentioning

confidence: 97%

Amplification, Saturation, andQThresholds for Runaway: Growth of Self‐Gravitating Structures in Models of Magnetized Galactic Gas Disks

Kim

Ostriker

2001

ApJ

129

152

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We investigate the susceptibility of gaseous, magnetized galactic disks to the formation of selfgravitating condensations using two-dimensional, local models. We focus on two issues : (1) determining the threshold condition for gravitational runaway, taking into account nonlinear e †ects ; and (2) distinguishing the magneto-Jeans instability (MJI) that arises under inner galaxy rotation curves from the modiÐed swing ampliÐcation (MSA) that arises under outer galaxy rotation curves. For axisymmetric density Ñuctuations, instability is known to require a Toomre parameter Q \ 1. For nonaxisymmetric Ñuctuations, any nonzero shear q 4 [d ln )/d ln R winds up wave fronts such that in linear theory ampliÐcation saturates. Any Q threshold for nonaxisymmetric gravitational runaway must originate from nonlinear e †ects. We use numerical magnetohydrodynamic simulations to demonstrate the anticipated threshold phenomenon, to analyze the nonlinear processes involved, and to evaluate the critical value Q c for stabilization. We Ðnd for a wide variety of conditions, with the largest values corre-Q c D 1.2È1.4 sponding to nonzero but subthermal mean magnetic Ðelds. Our Ðndings for are similar to those Q c inferred from thresholds for active star formation in the outer regions of spiral galaxies. MJI is distinct from MSA in that opposition to Coriolis forces by magnetic tension, rather than cooperation of epicyclic motion with kinematic shear, enables nonaxisymmetric density perturbations to grow. We suggest that under low-shear inner disk conditions, will be larger than that in outer disks by a factor Q c D(v A /qc s )1@2, where and are the respective and sound speeds. v A c s Alfven

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“…The nuclear emission of the prototypical starburst galaxy M82 was derived using the data of Telesco et al (1991). From their Figure 5, we estimate that the upper limit to the contribution of the nucleus is 200 mJy, which corresponds to one contour spacing in their Ðgure.…”

Section: Appendix Amentioning

confidence: 99%

“…From their Figure 5, we estimate that the upper limit to the contribution of the nucleus is 200 mJy, which corresponds to one contour spacing in their Ðgure. The foreground extinction was estimated using Telesco et al (1991) and Satyapal et al (1995). M82 shows variable hard X-ray Ñux (Ptak & Griffiths 1999 ;Matsumoto & Tsuru 1999), which led these authors to speculate about whether M82 might be harboring an AGN.…”

Section: Appendix Amentioning

confidence: 99%

N‐Band Imaging of Seyfert Nuclei and the Mid‐Infrared–X‐Ray Correlation

Krabbe¹,

Maiolino²

2001

ApJ

111

118

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We present new mid-infrared (N-band) images of a sample of eight nearby Seyfert galaxies. In all of our targets, we detect a central unresolved source, which in some cases has been identiÐed for the Ðrst time. In particular, we have detected the mid-infrared emission from the active nucleus of NGC 4945, which previously remained undetected at any wavelength but hard X-rays. We also detect circumnuclear extended emission in the Circinus galaxy along its major axis and Ðnd marginal evidence for extended circumnuclear emission in NGC 3281. The high spatial resolution of our data allows us to separate (1A .7) the Ñux of the nuclear point sources from the extended circumnuclear starburst (if present). We complement our sample with literature data for a number of nonactive starburst galaxies and relate the nuclear N-band Ñux to published hard (2È10 keV) X-ray Ñuxes. We Ðnd tight and well-separated correlations between the nuclear N-band Ñux and X-ray Ñux for both Seyfert and starburst nuclei that span over 3 orders of magnitude in luminosity. We demonstrate that these correlations can be used as a powerful classiÐcation tool for galactic nuclei. For example, we Ðnd strong evidence against NGC 1808 currently harboring an active Seyfert nucleus based on its position in the mid-infraredÈX-ray diagram. On the other hand, we conÐrm that NGC 4945 is in fact a Seyfert 2 galaxy.

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Infrared mapping of M82 - A starburst in an edge-on barred galaxy

Cited by 79 publications

References 0 publications

ISOCAM view of the starburst galaxies M 82, NGC 253 and NGC 1808

ISOCAM view of the starburst galaxies M 82, NGC 253 and NGC 1808

Amplification, Saturation, andQThresholds for Runaway: Growth of Self‐Gravitating Structures in Models of Magnetized Galactic Gas Disks

N‐Band Imaging of Seyfert Nuclei and the Mid‐Infrared–X‐Ray Correlation

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