Title: Exposing the Binary Heart of eta-Carinae

Title: Exposing the Binary Heart of eta-Carinae with Gamma-Rays

Proposal ID: 0120039
Subject category: Others
Principal investigator: Butt
Institute: Harvard-Smithsonian Center for Astrophysics (CfA)

Abstract

Our observations with ROSAT, ASCA, RXTE, Beppo-SAX, & CHANDRA, along with information from near-IR & Radio, all suggest that the super-luminous & super-massive star eta-Carinae may be, in fact, a 5.52 yr period eccentric binary system. The spatial resolution of IBIS affords us to separate gamma-rays from other sources in the rich Carina field, for the FIRST time ever, and examine directly the "heart" of eta-Carinae. Gamma-ray observations of eta-Carinae will severely test the binary hypothesis for this object, which predicts a DECREASED x-ray, but ENHANCED gamma-ray luminosity just after the putative periastron in 2003.47 (for which we will be requesting a fixed time AO2 observation). In order to correctly interpret those data, and to understand the nature of eta-Carinae in its "normal" state, we propose an unconstrained observation in this AO. The simultaneous & cross-calibrated data from the twin JEM-X's and IBIS will suit our science aims perfectly. The large 17degx17deg fully coded, dithered, IBIS field will also allow us to: 1. Identify/Verify 5 EGRET sources in the extended field.[IBIS] 2. Examine timing of the bright Anomalous X-ray Pulsar 1E1048.1-5937. [JEM-X/IBIS] 3. Twenty Radio supernova remnants (SNR's) will be in the extended IBIS field; Sixteen for JEM-X's. Eight have no identified x-ray counter-parts. Detection of hard x-ray non-thermal emission could be made. [JEM-X,IBIS] 4. The 511 keV line may be detected and mapped; cold-cloud/warm cloud shapes could be compared -- the 3.5 degree scale of the extended Carina cloud complex is well suited to SPI's 2.5deg resolution[SPI] 5. Cross-correlate our measured CO(J=4-->3) 460 GHz "hot spots", with hard x-ray/gamma-ray "hot-spots" viewed by JEM-X/IBIS/SPI. 6. Off-pointed dither fields will provide information on the soft-gamma background. 7. Off-pointed dither fields will probe the "Carina Flare" Super-shell.