The Supernova Remnant Cassiopeia A at Millimeter Wavelengths

Wright, M. C. H.; Dickel, John R.; Koralesky, Barron; Rudnick, Lawrence

doi:10.1086/307270

Cited by 39 publications

(53 citation statements)

References 31 publications

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“…The 850µm image is presented in Fig. 1 and shows a ring-like morphology, similar to the X-ray and radio images 18,19 .…”

supporting

confidence: 61%

“…3, the synchrotron contribution is now only one third and emission from cold dust dominates which is why the 450 and 850µm images appear different. We can remove the synchrotron contribution from the submm maps by scaling an 83 GHz image, 19 which is the closest in frequency and resolution to our images. Fig.…”

mentioning

confidence: 99%

“…If the remnant has swept up ISM material with a uniform density 19 it has swept up about as much mass as it ejected (< 15M ⊙ )). Another hypothesis for the bright ring seen in the X-ray and radio is that it is the interaction of the supernova with a stellar wind shell swept up by the Wolf-Rayet precursor 16,22 .…”

mentioning

confidence: 99%

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Type II supernovae as a significant source of interstellar dust

Dunne

Eales

Ivison

et al. 2003

Nature

252

323

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Large amounts of dust (> 10 8 M ⊙ ) have recently been discovered in high redshifts quasars 1,2 and galaxies 3−5 , corresponding to a time when the Universe was less than one-tenth of its present age. The stellar winds produced by stars in the late stages of their evolution (on the asymptotic giant branch of the Hertzsprung-Russell diagram) are though to be the main source of dust in galaxies, but they cannot produce that dust on a short-enough timescale 6 (< 1 Gyr) to explain the results in the high-redshift galaxies.Supernova explosions of massive stars (type II) are also a potential source, with models predicting 0.2-4 M ⊙ of dust 7−10 . As massive stars evolve rapidly, on timescales of a few Myr, these supernovae could be responsible for the high-redshift dust. Observations 11−13 of supernova remnants in the Milky Way, however, have hitherto revealed only 10 −7 − 10 −3 M ⊙ of dust each, which is insufficient to explain the high-redshift data. Here we report the detection of ∼ 2 − 4 M ⊙ of cold dust in the youngest known Galactic remnant, Cassiopeia A. This observation implies that supernovae are at least as important as stellar winds in producing dust in our Galaxy and would have been the dominant source of dust at high redshifts.Over the past three decades, many searches for dust in supernova remnants (SNR) have been made in the mid and far-infrared (6-100µm). Remnants must be studied when they are young, before they have swept up large masses of interstellar material which makes it difficult to distinguish dust formed in the ejecta from that present in the ISM prior to the explosion. The handful of Galactic remnants which are both young and close enough (Cas A, Kepler and Tycho) have been studied with the Infrared Astronomical Satellite (IRAS) and the Infrared Space Observatory (ISO), but although dust at 100-200 K has been detected, the dust mass deduced is only 10 −7 − 10 −3 M ⊙ , many orders of magnitude lower than the solar mass quantities predicted. 11−13 The formation of dust in the recent supernova 1987A has been implied indirectly from the fading of the silicate line and increase in 10µm emission, 14 although the quantity is heavily dependant on the assumptions made 1

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“…The 850µm image is presented in Fig. 1 and shows a ring-like morphology, similar to the X-ray and radio images 18,19 .…”

supporting

confidence: 61%

mentioning

confidence: 99%

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Type II supernovae as a significant source of interstellar dust

Dunne

Eales

Ivison

et al. 2003

Nature

252

323

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“…The restoration process produces sub-mm emission maps at 850 and 450 µm. A map of the synchrotron emission (see e.g., Wright et al 1999), scaled in frequency, was subtracted from these images. The final 450 µm image is given in Fig.…”

Section: Qualitative Comparisonmentioning

confidence: 99%

An alternate estimate of the mass of dust in Cassiopeia A

Wilson

Batrla

2005

A&A

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Abstract. Recent observations of sub-millimeter continuum emission toward supernova remnants (SNR) have raised the question of whether such emission is caused by dust within the SNR itself or along the line-of-sight. Here we make a comparison of the image of sub-mm emission from dust with the integrated J = 1−0 line emission from interstellar 13 CO toward the SNR Cassiopeia A based on existing data. The cm and mm synchrotron emission from Cas A has a rather symmetric, ringlike structure whereas both the sub-mm continuum and interstellar 13 CO line emission are located mostly toward the south of the SNR. There is positional agreement for 3 of 6 maxima found in 13 CO line and sub-mm continuum emission, with the weakest feature near the center of Cas A and the other two features near the southeast and west edges of the SNR. For these three maxima, a comparison of masses determined from dust and 13 CO data shows good agreement if we use the 450 µm dust absorption coefficient typical for diffuse clouds. There is also good agreement between the sub-mm dust temperature and the gas kinetic temperature from CO and NH 3 . For the remaining sub-mm continuum peaks, one is outside the forward shock of the SNR. For the other two, one was not mapped in 13 CO; for the other there is no 13 CO emission. H absorption covers all of Cas A, but the H column density may be too small to account for the sub-mm dust emission. Thus it is possible that one, or perhaps two of these sub-mm continuum peaks are located inside the SNR. From lower resolution maps in CO lines, the SE and W features are the edges of extended clouds. Toward the cloud centers, the CO emission is more intense, but there appears to be less sub-mm dust emission. The differences between CO and sub-mm images may be caused a combination of the techniques used to produce the sub-mm maps and changes in cloud properties from center to edge.

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“…It was used, e.g., by Wright et al (1999) in their multifrequency analysis of Cas A by applying a bandpass filter in the Fourier plane. In terms of removing large-scale features, this is equivalent to subtracting a convolved image from the original one.…”

Section: Summary Of Spectral Index Determination Methodsmentioning

confidence: 99%

Simple Multiresolution Filtering and the Spectra of Radio Galaxies and Supernova Remnants

Rudnick

2002

PUBL ASTRON SOC PAC

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ABSTRACT.A simple method is explored for examining the structures and spectral index distributions on different scales in Galactic and extragalactic radio sources, based on a multiresolution filtering technique suggested by Starck, Murtagh, & Bijaoui. Multiresolution filtering, whether in this simple algorithm or more sophisticated ones, is also useful for a wide variety of image analysis purposes. For spectral index studies, the filtering is complementary to other methods and is especially useful in separating large-scale and small-scale features with different spectral distributions. In this paper, filtered spectral distributions are produced for several sources. In the extragalactic sources, different spectral gradients are found for narrow and broad features as a function of distance from the terminal hot spots. This complicates the standard analyses used to understand relativistic particle acceleration and losses. We show that the high-field regions can yield either flatter or steeper spectra than lowfield regions and be either brighter or fainter, depending on the particle history. In our supernova remnant example, Cas A, the spectra of the fine-scale features are found, in the mean, to be flatter than those on larger scales. In addition, a clear asymmetry is found in the spectral indices of the largest scale emission and is related to other physical properties of the remnant.

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The Supernova Remnant Cassiopeia A at Millimeter Wavelengths

Cited by 39 publications

References 31 publications

Type II supernovae as a significant source of interstellar dust

Type II supernovae as a significant source of interstellar dust

An alternate estimate of the mass of dust in Cassiopeia A

Simple Multiresolution Filtering and the Spectra of Radio Galaxies and Supernova Remnants

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