finding the first cosmic explosions
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Finding The First Cosmic Explosions
Daniel Whalen Carnegie Mellon University
Chris Fryer, Lucy FreyLANL
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~ 200 pc
CosmologicalHalo z ~ 20
Properties of the First Stars
• form in isolation (one per halo)
• very massive (25 - 500 solar masses) due to inefficient H2 cooling
• Tsurface ~ 100,000 K
• extremely luminous sources of ionizing and LW photons (> 1050 photons s-1)
• 2 - 3 Myr lifetimes
Transformation of the HaloWhalen, Abel & Norman 2004, ApJ, 610, 14
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Primordial Ionization Front InstabilitiesWhalen & Norman 2008, ApJ, 675, 644
Final Fates of the First Stars Heger & Woosley 2002, ApJ 567, 532
Post Processing Includes Detailed LANL Opacities
but the atomic levels areassumed to be in equilibrium,a clear approximation
PISN Shock Breakout
• X-rays (> 100 eV)
• transient (a few hours in the local frame)
Spectra atBreakout
The spectra evolverapidly as the frontcools
Long-TermLight-CurveEvolution
even the lowestenergy PISN at z ~ 10 produces a large signal inthe JWST NIR camera over the first 50 days
Late Time Spectra
spectral features after breakout may enable usto distinguish betweenPISN and CC SNe
larger parameter studywith well-resolved photospheres is now inprogress
Chemical Mixing Prior to Breakout
Joggerst & Whalen 2010, ApJ in prep
PISNCore Collapse SN
Joggerst, Whalen, et al 2010, ApJ, 709, 11
Roadmap Ahead
• current models are grey FLD; next step is multigroup FLD and then multigroup IMC
• advance from 1D RTP AMR calculations to 2D cartesian AMR grids
• incorporate mixing from 2D models to simulate core-collapse SNe (15 - 40 solar mass stars, hypernovae)
• implement non-equilibrium opacities
• investigate progenitor environments on LC and spectra (LBV brightening?)
• explore asymmetric explosion mechanisms
• evolve toward 2D AMR IMC rad hydro with thousands of frequency bins -- eliminate post processing
Conclusions
• PISN will be visible to JWST out to z ~ 15; strong lensing may enable their detection out to z ~ 20 (Holz, Whalen & Fryer 2010 ApJ in prep)
• however, the redshifted initial x-ray transient will likely fall outside of the trigger wavelength of SWIFT and its envisioned successors
• as a consequence, first detection of PISN by JWST would be serendipitous
• dedicated ground-based campaigns with 30-meter class telescopes are the most probable avenue to finding the first SN explosions
• discrimination between Pop III PISN and Pop III CC SNe will be challenging but offers the first direct constraints on the Pop III IMF
• complementary detection of Pop III PISN remnants by the SZ effect may be possible (Whalen, Bhattacharya & Holz 2010, ApJ in prep)
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