A COOL DUST FACTORY IN THE CRAB NEBULA: AHERSCHELSTUDY OF THE FILAMENTS

Abstract

Whether supernovae are major sources of dust in galaxies is a long-standing debate. We present infrared and submillimeter photometry and spectroscopy from the Herschel Space Observatory of the Crab Nebula between 51 and 670 µm as part of the Mass Loss from Evolved StarS program. We compare the emission detected with Herschel with multiwavelength data including millimeter, radio, mid-infrared and archive optical images. We carefully remove the synchrotron component using the Herschel and Planck fluxes measured in the same epoch. The contribution from line emission is removed using Herschel spectroscopy combined with Infrared Space Observatory archive data. Several forbidden lines of carbon, oxygen and nitrogen are detected where multiple velocity components are resolved, deduced to be from the nitrogen-depleted, carbon-rich ejecta. No spectral lines are detected in the SPIRE wavebands; in the PACS bands, the line contribution is 5% and 10% at 70 and 100 µm and negligible at 160 µm. After subtracting the synchrotron and line emission, the remaining farinfrared continuum can be fit with two dust components. Assuming standard interstellar silicates, the mass of the cooler component is 0.24 +0.32 −0.08 M ⊙ for T = 28.1 +5.5 −3.2 K. Amorphous carbon grains require 0.11 ± 0.01 M ⊙ of dust with T = 33.8 +2.3 −1.8 K. A single temperature modified blackbody with 0.14 M ⊙ and 0.08 M ⊙ for silicate and carbon dust respectively, provides an adequate fit to the farinfrared region of the spectral energy distribution but is a poor fit at 24-500 µm. The Crab Nebula has condensed most of the relevant refractory elements into dust, suggesting the formation of dust in core-collapse supernova ejecta is efficient.

Dust production 680–850 million years after the Big Bang

“…remnants of Cassiopeia A ) and Kepler Gomez et al 2009) Matsuura et al 2011;Indebetouw et al 2014), and the Crab Nebula (∼0.02-0.2 M Gomez et al 2012;Temim & Dwek 2013). However, the high dust yields for Cassiopeia A and Kepler are still controversial (Dwek 2004;Krause et al 2004;Gomez et al 2005;Wilson & Batrla 2005;Blair et al 2007;Sibthorpe et al 2010;Barlow et al 2010), and dust masses for other SN remnants are typically much lower, of the order of 10 −3 -10 −2 M (Green et al 2004;Borkowski et al 2006;Sugerman et al 2006;Ercolano et al 2007;Meikle et al 2007;Rho et al 2008Rho et al , 2009Kotak et al 2009;Lee et al 2009;Sakon et al 2009;Sandstrom et al 2009;Wesson et al 2009;Gallagher et al 2012;Temim et al 2012).…”

Dust input from AGB stars in the Large Magellanic Cloud

“…However, many recent studies derive low efficiencies of dust condensation in SN ejecta from mid-and far-IR observations (e.g., Ercolano et al 2007;Rho et al 2008Rho et al , 2009Temim et al 2012), theoretical modelling of dust formation and survival in SN ejecta (Bianchi & Schneider 2007;Kozasa et al 2009;Cherchneff & Dwek 2009, and analysis of presolar grains with different origins found in meteorites . Recently, far-IR and submillimeter observations with the Herschel Space Observatory permitted the detection of larger masses of newly formed dust in SN ejecta (Matsuura et al 2011;Gomez et al 2012; see also Lakicevic et al 2011, for ground-based sub-mm observations), but it is still unclear what fraction of these grains will survive destruction in the reverse shocks of SN remnants (e.g., Silvia et al 2010Silvia et al , 2012. Given the controversies with dust input from SNe, AGB stars may be a dominant stellar source of dust production.…”

Dusty Supernovae Running the Thermodynamics of the Matter Reinserted Within Young and Massive Super Stellar Clusters

“…Notable cases are those of the SN 1987A (see Moseley et al 1989;Matsuura et al 2011), the Crab Nebula (Gomez et al 2012), Cas A (Hines et al 2004), as well as the undecided type Kepler SN (see Reynolds et al 2007;, leading in all cases to dust masses, M d , of the order of several tenths to a few solar masses. The implication is that the condensation of refractory elements into dust is very efficient in the ejecta of core-collapse SNe.…”