Supernovae in molecular clouds

Wheeler, J. C.; Mazurek, T. J.; Sivaramakrishnan, A.

doi:10.1086/157925

Cited by 65 publications

(54 citation statements)

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“…Note that this is different from the distance assumed in previous papers describing X-ray and radio observations (Fabian & Terlevich 1996;Aretxaga et al 1999;Shull 1980;Wheeler et al 1980;Williams et al 2002;see Table 1). …”

Section: Introductioncontrasting

confidence: 58%

AChandraACIS Observation of the X‐Ray–luminous SN 1988Z

Schlegel

Petre

2006

ApJ

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SN 1988Z is the most luminous X-ray-emitting supernova, initially detected in 1995 using the ROSAT HRI with a luminosity of $8 ; 10 40 ergs s À1 (Fabian & Terlevich 1996). Its high luminosity was ascribed to expansion of the blast wave into an especially dense circumstellar medium. In this paper, we describe a recent observation of SN 1988Z using the ACIS detector on Chandra. We readily detect SN 1988Z, obtaining $30 net counts, which corresponds to a 0.2-2.0 keV luminosity of $3:2 ; 10 39 ergs s À1 . The calculated quantiles for the extracted counts allow a broad range of temperatures but require a temperature hotter than 5 keV if there is no intrinsic absorption. The long-term light curve (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) declines as t À2:6AE0:6 . This is one of the steepest X-ray light curves. The X-ray luminosity indicates that the emitting region has a high density (>10 5 cm À3 ) and that the density profile is not consistent with a constant mass-loss stellar wind during the $5000 yr before the explosion. If the circumstellar medium is due to progenitor mass loss, then the mass-loss rate is extremely high ($10 À3 M yr À1 [v w /10 km s À1 ]). The X-ray results are compared with the predictions of models of SN 1988Z. Subject headingg : supernovae: individual (SN 1988Z) Online material: color figure

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Section: Introductioncontrasting

confidence: 58%

AChandraACIS Observation of the X‐Ray–luminous SN 1988Z

Schlegel

Petre

2006

ApJ

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“…Despite this the sharpness of the observed minimum cutoff in size suggests that the observed Arp220 SNRs are not embedded in densities > 10 5 cm −3 . This is either because such high-density gas has low volume filling factor in Arp220 or because SNRs become inefficient radio sources (Wheeler et al 1980) when embedded in such high-density regions.…”

Section: Comparison Of Sne and Snrs Sizesmentioning

confidence: 99%

RESOLUTION OF THE COMPACT RADIO CONTINUUM SOURCES IN Arp220

Batejat

Conway

Hurley

et al. 2011

ApJ

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We present 2 cm and 3.6 cm wavelength very long baseline interferometry images of the compact radio continuum sources in the nearby ultra-luminous infrared galaxy Arp220. Based on their radio spectra and variability properties, we confirm these sources to be a mixture of supernovae (SNe) and supernova remnants (SNRs). Of the 17 detected sources we resolve 7 at both wavelengths. The SNe generally only have upper size limits. In contrast all the SNRs are resolved with diameters 0.27 pc. This size limit is consistent with them having just entered their Sedov phase while embedded in an interstellar medium (ISM) of density 10 4 cm −3 . These objects lie on the diameter-luminosity correlation for SNRs (and so also on the diameter-surface brightness relation) and extend these correlations to very small sources. The data are consistent with the relation L ∝ D −9/4 . Revised equipartition arguments adjusted to a magnetic field to a relativistic particle energy density ratio of 1% combined with a reasonable synchrotron-emitting volume filling factor of 10% give estimated magnetic field strengths in the SNR shells of ∼15-50 mG. The SNR shell magnetic fields are unlikely to come from compression of ambient ISM fields and must instead be internally generated. We set an upper limit of 7 mG for the ISM magnetic field. The estimated energy in relativistic particles, 2%-20% of the explosion kinetic energy, is consistent with estimates from models that fit the IR-radio correlation in compact starburst galaxies.

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“…Not all of this energy goes into the mechanical feedback, as part of the energy is radiated away in thin, dense shells surrounding the bubbles created by the supernovae, that are unresolved in our simulations. We assume that 10% of the total supernova energy goes into mechanical feedback on the gas (Wheeler et al 1980;Silich et al 1996). The feedback is incorporated in the code with the use of pressure particles (Pelupessy et al 2004;Pelupessy 2005).…”

Section: Star Formation and Feedbackmentioning

confidence: 99%

The escape of ionising radiation from high-redshift dwarf galaxies

Paardekooper

Pelupessy

Altay³

et al. 2011

A&A

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Context. The UV escape fraction from high-redshift galaxies plays a key role in models of cosmic reionisation. Because it is currently not possible to deduce the escape fractions during the epoch of reionisation from observations, we have to rely on numerical simulations. Aims. We aim to better constrain the escape fraction from high-redshift dwarf galaxies, as these are the most likely sources responsible for reionising the Universe. Methods. We employ a N-body/SPH method that includes realistic prescriptions for the physical processes that are important for the evolution of dwarf galaxies. These models are post-processed with radiative transfer to determine the escape fraction of ionising radiation. We perform a parameter study to assess the influence of the spin parameter, gas fraction and formation redshift of the galaxy and study the importance of numerical parameters as resolution, source distribution and local gas clearing. Results. We find that the UV escape fraction from high-redshift dwarf galaxies that have formed a rotationally supported disc lie between 10 −5 and 0.1. The mass and angular momentum of the galaxy are the most important parameters that determine the escape fraction. We compare our results to previous work and discuss the uncertainties of our models. Conclusions. The low escape fraction we find for high-redshift dwarf galaxies is balanced by their high stellar content, resulting in an efficiency parameter for stars that is only marginally lower than the values found by semi-analytic models of reionisation. We therefore conclude that dwarf galaxies play an important role in cosmic reionisation also after the initial starburst phase, when the gas has settled into a disc.

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Supernovae in molecular clouds

Cited by 65 publications

References 0 publications

AChandraACIS Observation of the X‐Ray–luminous SN 1988Z

AChandraACIS Observation of the X‐Ray–luminous SN 1988Z

RESOLUTION OF THE COMPACT RADIO CONTINUUM SOURCES IN Arp220

The escape of ionising radiation from high-redshift dwarf galaxies

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