World Cup of VHE Gamma Rays J-Dog, for the SNR/PWN Pack

SNR Types/Evolution Type Ia: result from accretion in a binary; explosion typically into ~uniform medium. Type II: core collapse of a ~8-15 M  star; explosion into slow (~10 km/s) wind; neutron star left behind. Type Ib: core collapse of a >~15 M  star; explosion into fast (~1000 km/s) wind; black hole left behind. All yield ~0.5 – 2.0 · erg initial ejecta kinetic energy. –Rate of ~3/century  need ~16% energy converted to CRs to maintain galactic CR flux. Sedov phase begins – mass of swept-up material = ejecta energy. –Usually takes few 100 – few 1000 years to reach. –SN energy now split roughly evenly between bulk kinetic, thermal, and relativistic particles. –Beginning of Sedov phase is when gamma-ray emission from CR-proton interactions (pion decay) is expected to peak. –SNR expands adiabatically for ~100 kyr until gas cools enough to radiate efficiently, starting a phase of rapid cooling.

PWN Overview Evolution of a PWN Expansion Phase nebula expands into cold gas medium Interaction with reverse shock compression and transition to hot gas medium possible distortion of nebula by asymmetric reverse shock arrival Sedov Phase pulsar exits the original relic nebula and generates a new smaller nebula. At ~2/3 distance to the forward shock becomes supersonic and generates a bow shock Interstellar Gas Phase – “the pulsar has left the building” Gaensler & Slane, 2006

SNR/PWN Science: Morphology Resolve locations of maximum particle acceleration in nearby remnants in SNR shells (RXJ 1713, Vela Jr) to distinguish nebula emission from shell (e.g. G ) to resolve jets in jet-dominated PWN (MSH 15-52) PWN evolution indicators pulsar/X-ray/TeV nebula offsets  inhomogeneous interaction with reverse shock (Vela X, G , Kookaburra, Rabbit) TeV vs X-ray size  differing synchrotron lifetimes (G ) RXJ MSH Vela X G (contours VLA)

Utility of MWL Information (from Aharonian, etal., arXiv:astro-ph/ ) Radio + X-ray + TeV: Constrain species of emitting particles X-ray + TeV:Constrain history of nebula’s magnetic field Constrain shell magnetic field Morphology  effect of reverse shock, medium homogeniety X-ray + GeV + TeV:Study nebula’s synchrotron cooling GeV + TeV:Study effect of CRs on shell dynamics

Key Project Justification I Science Motivation: Understand the role of SNRs in cosmic-ray acceleration. Study particle acceleration (ion and electron) mechanisms. –Maximum energy achievable in shock acceleration. –Resolution of jet structure, pulsar and X-ray nebula offsets, Doppler boosting. Use the spectral shape, morphology, and MWL information to discriminate between acceleration models. –Even upper limits can place important constraints on models. –What are the conditions that lead to efficient cosmic-ray acceleration? –Extending spectrum to GeV with GLAST, study modification of shock dynamics by cosmic rays. Study shell/nebula structure and evolution. –Constrain shell, nebula magnetic fields. –Reverse shock compression/asymmetries in surrounding medium. –Measure synch. cooling break, particularly in combination with GLAST. –TeV provides integrated history of injected electron population while X-ray indicates recent history. –Expansion rate and age of nebula. Probe interstellar medium. –Indirect measure of local photon densities.

Key Project Justification II Discovery Potential: The largest class of objects that HESS has detected is SNRs/PWNe. Most of the HESS sources are in a region of the galactic plane at a distance of ~4-10 kpc, whereas the region of the plane visible to VERITAS (~30 o < l < ~220 o ) contains spiral arms at ~2-4 kpc. SNRs and PWNe are steady sources and have fairly hard spectra (index ~ ), making them more readily detectable with a new instrument. Why VERITAS? Cas A, Tycho, 3C 58, and J2021 are unobservable by HESS/CANGAROO. VERITAS has better sensitivity than MAGIC for extended sources and at higher energies. Why a Key Project? These objects form a set of the best known candidates of different classes of SNRs/PWNe; synergy between them maximizes their science reach.

Proposal I Year I: Observe a number of SNRs/PWNe with sensitivity to detect or set limits at few % Crab level. Year II: We anticipate a request of ~ hours. –Follow up of sources detected in the first year. –Follow up of Sky Survey and GLAST detections. MonthPrimary TargetsSecondary OctJ2021Cas A3C 58 NovCas ATychoJ2021 DecCas ATycho3C 58 JanIC 443Monoceros FebIC 443Monoceros

Proposal II ObjectJ2021Cas ATycho3C 58IC 443Mono Shell PWN Progenitor TypeCC IaCC ? Cloud Interaction MonthsOct- Nov Oct- Dec Nov- Dec Oct- Dec Jan- Feb Hours1025 *CC: Core collapse

SNR/PWN Observability ( > 55 deg) Hours per Year (Jul, Aug, Sept excluded) ~ Sky survey region Midi W49B Mono IC443 Crab J1930 Cygnus Loop W44 CTB80 CTB87  Cygni J2021 Tycho Cas A 3C58 R5 DA530 J2229

Summary Is that the end?

Additional Info

3C 58 (G ) Powered by 3 rd most energetic pulsar in the galaxy, J (after Crab and G ). Relatively nearby at 3.2 kpc. Possible association with SN 1181 but observations imply an older object. –age important for X-ray constraints on neutron star cooling. Crab-like morphology (jet/torus). Low magnetic field  e - producing TeV emit synchrotron in the UV band. –TeV probes otherwise unobservable section of e - spectrum. –Similar nebula of PSR B detected in TeV.

IC 443

J