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Supernovae and Their Interaction with Their Surroundings. Roger Chevalier University of Virginia. X-ray, Chandra. Strongly interacting supernovae. Mass loss processes in years to up to 1000’s of years leading up to the supernova Shock physics at high density Constraints on explosion energy.
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Supernovae and Their Interactionwith Their Surroundings Roger Chevalier University of Virginia X-ray, Chandra
Strongly interacting supernovae Mass loss processes in years to up to 1000’s of years leading up to the supernova Shock physics at high density Constraints on explosion energy
Circumstellar interaction at low density (e.g. IIP) X-ray and radio emission
Superluminous IIn’s Ia IIP Zhang+ 12
SN 2010jl Smith et al 2008 SN 2010jl Ha narrow P Cygni line 100 km/s el. scatt. wing Broad Ha formed by electron scattering in the wind (Chugai 2001 on SN 1998S) Requires Thomson optical depth of > 1 in the wind
SN 2010jl 6000 K 1900 K 6 Fransson+ 13
SN 2010jlX-Rays (Chandra) Dec 2010 (t=2 mnth), 7e41 ergs/s (unabs), NH~1e24 cm-2, T≥10 keV Oct 2011, 7e41 ergs/s, NH~3e23 cm-2, T≥10 keV Jun 2012, 5e41 ergs/s, NH~5e22 cm-2, T≥10 keV P. Chandra, RAC,…
Optically thick (in optical) X-ray emission (radio absorbed at high Mdot) X-ray photoionized region At high densities, the hard, forward shock X-ray emission dominates
SN 2006gy SN 2010jl D*=1 0.1 M/yr at 100 km/s RAC + Irwin 2012
Asymmetry Substantial (2%) continuum polarization seen in SN 2010jl and other SN IIn (1997eg, 1998S). Not in Ha core Column density to X-ray source smaller than that needed for optical line wings Dust extinction smaller than if emitting dust were on line of sight SN 2010jl Patat et al. 11
He at ~5000 km/s He I Pg Pd Pb Borish, RAC,…
Categories of Type IIn (Taddia et al.) • SN 1994W-like (or IIn-P) • Plateau 100-150 days, followed by drop • SN 1998S-like • Steeper light curve • n characteristics observed only early • SN 1988Z-like • Long lived • Often accompanied by radio, X-ray, infrared
SN 1994W-like Drop in light curve at ~ 120 days Mauerhan+ 13
SN 2011ht (IIn) A likely case of shock breakout in csm with t > c/vs The temperature reaches a maximum at the same time as the luminosity Roming et al. 12
Another possible breakout event High mass loss in year(s) leading to explosion Low energy likely Taddia+ 2013
1998S-like IIn characteristics only in first week Later development of broad lines and Ha emission Likely at low end of mass loss for a IIn (2×10-4 M/yr)
Superluminous IIn’s Ia IIP Zhang+ 12
1.5 x 1039 erg/s SN2006gy X-rays 1.5 x 1039 erg/s soft (Smith et al. 2007) < 1 x 1040 erg/s (Ofek et al. 2007) L(optical) ~ 2 x 1044 erg/s
Breakout X-rays decreased by • Inverse Compton cooling by photospheric photons more important than bremsstrahlung • Comptonization in the cool wind reduces energy of the highest energy photons • down to ~me c2/τ2 = 511/τ2 keV • Photoelectric absorption in the cool wind • Photoionization can be a factor
SN 2010gx and related objectsSuperluminous Type I (not n) Pastorello et al. 2010
Possible power sources Radioactivity Circumstellar interaction Millisecond magnetar
SNe with dense surroundings What are they? Up to several M lost in yrs to 1000s of years before the explosion Velocity of circumstellar matter typically 100s km/s
Often associated with very massive stars • Analogy to Eta Carinae • Progenitor observations (Gal-Yam/Leonard, Smith) • SN 2005gl 60 M, SN 1961V 100-150 M, SN 2009ip 50-80 M, SN 2010jl >30 M BUT High luminosity from precursor interactions Population studies of IIn imply lower mass
SNe IIn not associated with blue light any more than SN II. SNe IIb and Ic-BL are. Also, positions in host galaxies like SN II. Kelly & Kirshner 2012
Proposals for dense surroundings Mass loss driven by gravity-waves from convection in late burning phases (Quataert & Shiode 12, SQ 13) Pulsational pair instability (Woosley+ 07) Binaries (RAC 12, Barkov & Komissarov 11, Thone et al 12, Soker 12)
Massive star binary Supernova Neutron star Common envelope Mass loss Inspiral stops outside core Inspiral continues (closer binary) NS/BH He star SN BH TZO SN Inspiral M loss + TZO SN BH
SN IIn observations Binary scenario Outflow velocity related to escape velocity: 100’s of km/s Up to solar masses in <1000 yr before explosion Rate estimated from # of HMXBs >2e-4 yr-1 in Galaxy (Podsiadlowski…) Asymmetric mass loss • Narrow emission and absorption lines give 100 to 1000 km/s • Up to solar masses in 10’s to 100’s of yr before explosion • Rate is 4-7% of CCSN rate, so (8-13)e-4 yr-1 in Galaxy (W. Li,….) • Asymmetry
Rest+ 2011 SN 2003ma Radiated ~4e51 ergs over 4.7 yr Estimate >1052 ergs explosion energy
Conclusions • Most core collapse supernovae have low density surroundings, consistent with the progenitor star wind • Some supernovae have dense surroundings • An extended, optically thick medium gives IIn characteristics • They can be optically highly luminous, although X-ray faint • Superluminous supernovae without “n” characteristics may also be powered by dense interaction • Reason for the dense mass loss uncertain – common envelope evolution is a suggestion