Basic Feasibility for the LXO Jenny Carter jac

Basic Feasibility for the LXO Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Basis for this study � Base on model of Robertson and Cravens, Geo. Phys Res. Letters, Vol. 30, No. 8, 1439, X-ray emission from the terrestrial magnetosheath � Max – 8. 8 ke. V cm-2 s-1 sr-1 � MCP optic plus MOS type CCD cameras at focal plane � Plan to model this instrument concept using Xspec to find expected count rates, signal-to-noise etc. Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Selected areas � Select various FOV and calculate flux within the relevant solid angle FOV (º) 5 x 5 Solid Angle (str) 0. 007 Flux ke. V s-1 cm-2 / ergs s-1 cm-2 0. 049 / 7. 90× 10 -11 9 x 9 0. 024 0. 144 / 2. 31× 10 -10 20 x 20 0. 123 0. 551 / 8. 83× 10 -10 30 x 30 0. 284 1. 06 / 1. 70× 10 -9 Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Effective area � Create arf using LOBSTER bkg effective area curve (Simon Vaughan, www. star. le. ac. uk/lwft/poster. pdf) � (Improvement on previous work, adapting MOS arf for MCP optic, lack of RGA etc. ) Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Model basis � Snowden et al. , HDFN and SWCX, Ap. J, 610, 1182, 2004 � Use Snowden response matrix initially � SWCX lines, plus use background components � Relative normalisations taken from Snowden paper. Line C VI O VIII Ne IX Mg XI Energy (ke. V) 0. 37 0. 46 0. 56 0. 65 0. 81 0. 91 1. 34 Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Spectra and Bkg � Fake spectra, sky bkg and particle background separately � Use MOS response matrix and lobster effective area � Scale each spectrum to match the flux in Robertson and Cravens model between 0. 2 and 2 ke. V � Sky background assumed to be 10 photons cm-2 s-1 sr-1 at 1 ke. V, approx. value from Lumb et al. , 389, 93, 2002, scale accordingly � Scale particle background so that crosses sky background at 5 ke. V Sky: MW-halo, local halo, cosmic bkg, local hot bubble wabs * (raymond + powerlaw + raymond) + vapec + raymond PB: particle induced background powerlaw Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Limitations, extra bkg � No lunar background considered � Instrumental lines, depending on instrument used etc. � Local and temporal variations in the sky background � Specifics of particle induced background dependent on instrumental set up etc. Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Results – using MOS response Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Results – response matrix adapted Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Results – off centre selection Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Results Summary FOV (º) 9 x 9 30 x 30 9 x 9 Pos C C C O O O Time (ks) 10 1000 1000 CR – Sky CR – PB (ct s-1) 2. 96 5. 60 0. 06 21. 8 66. 2 0. 75 1. 39 5. 59 0. 06 Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007 S/N 103 319 1009 231 732 2317 52 165 522

Simulated images of fov � Andy Read; based on predicted count rates and distribution of model, distribute photons for different exposure times 1 ks, magnetosheath, sky bkg Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

More images 1 ks, resultant, smoothed Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

More images (2) 10 ks 100 ks Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007

LOBSTER optic designed for primary science goal as an ASM so optimises telescope grasp (fov x effective area) Eff. Area of nickelcoated glass MCP optic of varying focal lengths For LXO we would enhance soft X-ray sensitivity: f = 50 cm gives useful 90 x 90 fov in a compact form. Jenny Carter (jac 48@star. le. ac. uk) LXO Basic Feasibility 15 July 2007