Männerblicke

Brandt, Stefan L.

doi:10.1007/978-3-476-04285-9

Cited by 3 publications

(1 citation statement)

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“…NGC 185 has been classified as a low luminosity Seyfert type 2 galaxy, based on its optical and radio properties (Panessa et al 2006;Nagar et al 2005), although the presence of a black hole as a possible driver of this activity has not been confirmed in X-ray observations (Brandt et al 1997).…”

Section: Analysis Of the Spectramentioning

confidence: 99%

Dust Abundance and Properties in the Nearby Dwarf Galaxies NGC 147 and NGC 185

Marleau

Noriega-Crespo

Misselt

2010

ApJ

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We present new mid-to far-infrared images of the two dwarf compact elliptical galaxies that are satellites of M31, NGC 185 and NGC 147, obtained with the Spitzer Space Telescope. Spitzer's high sensitivity and spatial resolution enable us for the first time to look directly into the detailed spatial structure and properties of the dust in these systems. The images of NGC 185 at 8 and 24 micron display a mixed morphology characterized by a shell-like diffuse emission region surrounding a central concentration of more intense infrared emission. The lower resolution images at longer wavelengths show the same spatial distribution within the central 50 ′′ but beyond this radius, the 160µm emission is more extended than that at 24 and 70µm. On the other hand, the dwarf galaxy NGC 147 located only a small distance away from NGC 185 shows no significant infrared emission beyond 24 micron and therefore its diffuse infrared emission is mainly stellar in origin. For NGC 185, the derived dust mass based on the best fit to the spectral energy distribution is 1.9 × 10 3 M ⊙ , implying a gas mass of 3.0 × 10 5 M ⊙ . These values are in agreement with those previously estimated from infrared as well as CO and HI observations and are consistent with the predicted mass return from dying stars based on the last burst of star formation 1 × 10 9 yr ago. Based on the 70 to 160µm flux density ratio, we estimate a temperature for the dust of ∼ 17K. For NGC 147, we obtain an upper limit for the dust mass of 4.5 × 10 2 M ⊙ at 160µm (assuming a temperature of ∼ 20K), a value consistent with the previous upper limit derived using ISO observations of this galaxy. In the case of NGC 185, we also present full 5 − 38µm low-resolution

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Section: Analysis Of the Spectramentioning

confidence: 99%