VLA observations of three M 33 supernova remnants at 20 cm

Goss, W. M.; Viallefond, F.

doi:10.1007/bf02714994

Cited by 16 publications

(19 citation statements)

References 12 publications

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“…Blair, Chu & Kennicutt (1988) also give di erent diameters as determined from their echelle spectroscopy. Similarly, higher resolution VLA data (Goss & Viallefond 1985) shows that DDB-7 is substantially smaller than either Long et al or Duric et al report. We also nd a smaller diameter for this source ( 3:5 00 ) from an FeII] image obtained with IRCAM3 at UKIRT.…”

Section: Correlation Of Feii] Luminosity and Snr Propertiesmentioning

confidence: 76%

Forbidden Fe+ emission from supernova remnants in M33

Lumsden¹,

Puxley²

1995

Monthly Notices of the Royal Astronomical Society

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Supernovae remnants are known to be luminous sources of infrared FeII] emission. By studying how the luminosity scales with age, environment and other relevant factors, we can construct an FeII] luminosity function for supernovae remnants. This will enable us to predict supernovae rates in starburst galaxies that are too distant for individual remnants to be resolved. First, however, we require accurate luminosities for a sample of remnants of varying ages, and in varying physical environments. As part of this project we have carried out an initial study of a small sample of evolved (ages greater than a few thousand years) remnants in M33. From these data we tentatively conclude that there is evidence for the peak luminosity in the FeII] lines of these sources to arise in a narrow range of ages. In other respects, the M33 remnants are similar to their galactic and Magellanic Cloud counterparts in the observed peak luminosity. From this, and internal evidence as to the environment present in these regions, we conclude that the luminosity of evolved remnants is only marginally dependent on density and metallicity.

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Section: Correlation Of Feii] Luminosity and Snr Propertiesmentioning

confidence: 76%

Forbidden Fe+ emission from supernova remnants in M33

Lumsden¹,

Puxley²

1995

Monthly Notices of the Royal Astronomical Society

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“…By the late 1960s, it was known that some SNRs-notably W28, W44, and IC443-had these masers (25). In the following decade, it was pointed out that 1720-MHz masers could occur in warm molecular gas without the need for pumping by a FIR radiation field (26), suggestive of shocked gas, and that they might be associated with SNR-driven shock waves (27).…”

Section: S C I E N C E ' S C O M P a S Smentioning

confidence: 99%

Supernova Remnant OH Masers: Signposts of Cosmic Collision

Wardle

Yusef‐Zadeh

2002

Science

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A supernova explosion, the final death throe of a massive star, creates an expanding bubble of hot gas that overruns up the surrounding medium. When a supernova remnant encounters a dense interstellar cloud, the compression may trigger gravitational collapse and the formation of a new generation of stars. This event can be detected through intense stimulated emission in the 1720-megahertz transition of the hydroxyl radical, OH, which yields unique insights into the physical processes and conditions occurring during the interaction.

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“…IC 443 has become an especially rich target for molecular line observations, including (Burton et al H 2 1988 ;Richter, Graham, & Wright 1995a) ; CO and HCO ( Dickman et al 1992 ;Tauber et al 1994) ; HCN, CN, SiO, CS, SO, and (Turner et al 1992 ; van Dis-H 2 CO, C 2 H hoeck, Jansen, & Phillips 1993). Weaker evidence for interaction was found in CO observations of W44 andW28 (Wootten 1977, 1981), which were earlier found to be sources of OH 1720 MHz line emission (Goss & Robinson 1968). OH 1720 MHz maser line emission has emerged as a signpost of molecular interaction with the detection of compact OH emission from eight supernova remnants (Frail et al 1996), including W44, IC 443, and 3C 391.…”

Section: Introductionmentioning

confidence: 97%

“…These observations did show CO apparently in the vicinity of the remnant, although they did not conclusively show an interaction (DeNoyer 1983). However, Claussen et al (1997) have found compact OH masers in the direction of the remnant (Ðrst discovered by Goss & Robinson 1968) and Seta et al (1998) have recently found evidence for CO clouds that are interacting with the remnant. The remnant is elongated, with radii of 11 ] 15 pc ; because the present models are spherically symmetric, I take 13 pc for the radius.…”

Section: W 44mentioning

confidence: 99%

Supernova Remnants in Molecular Clouds

Chevalier

1999

ApJ

256

325

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Massive stars may end their lives in the molecular clouds in which they were born. O-type (Z8 M _ ) stars probably have sufficient photoionizing radiation and wind power to clear a region more than 15 pc in radius of molecular material. Early B stars (B1ÈB3 on the main sequence, or 8È12 stars) are not M _ capable of this and may interact directly with molecular gas when they explode. Molecular clouds are known to be clumpy, with dense molecular clumps occupying only a few percent of the volume. A supernova remnant then evolves primarily in the interclump medium, which has a density H atoms n H \ 5È25 cm~3. The remnant becomes radiative at a radius of D6 pc, forming a shell that is magnetically supported. The structure of the shell can be described by a self-similar solution. When this shell interacts with the dense clumps, the molecular shock fronts are driven by a considerable overpressure compared to the pressure in the rest of the remnant. The expected range of clump sizes leads to a complex velocity distribution, with the possibility of molecular gas accelerated to a high velocity. Observations of the remnants W44 and IC 443 can be understood in this model. W44 has a shell expanding at D150 km s~1 into a medium with density 4È5 cm~3. The shock emission expected in such a model is consistent with the observed Ha surface brightness and the [O I] 63 km line luminosity. The clump interaction is seen in OH maser emission, which shows a magnetic Ðeld strength that is consistent with that expected in the model. IC 443 appears to be expanding at a lower velocity, 100 km s~1, into an interclump medium with a higher density, D15 cm~3. The interaction of the radiative shell with molecular clumps can produce the molecular emission that is observed from IC 443. Both remnants are shell sources of radio synchrotron emission, which can be attributed to relativistic electrons in the cool radiative shell. If ambient cosmic-ray electrons are further accelerated by the shock front and by the postshock compression, the radio Ñuxes and the Ñat spectral indices of W44 and IC 443 can be explained. The energetic electrons are in a high-density shell and their bremsstrahlung emission can approximately produce the c-ray Ñuxes observed by EGRET. Molecular clouds have a signiÐcant uniform magnetic Ðeld component so that heat conduction is likely to be important in the hot interior and can explain the isothermal X-ray emission observed from the remnants.

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VLA observations of three M 33 supernova remnants at 20 cm

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Cited by 16 publications

References 12 publications

Forbidden Fe+ emission from supernova remnants in M33

Forbidden Fe+ emission from supernova remnants in M33

Supernova Remnant OH Masers: Signposts of Cosmic Collision

Supernova Remnants in Molecular Clouds

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