SWCX and Properties of the Local Hot Bubble from DXL Mission W. Liu, M. Galeazzi, M. Chiao, M.R. Collier, T. Cravens, D. Koutroumpa, K.D. Kuntz, R. Lallement, S.T. Lepri, D. McCammon, K. Morgan, F.S. Porter, K. Prasai, S.L. Snowden, N.E. Thomas, Y. Uprety, E. Ursino, B.M. Walsh

OUTLINE the Local Hot Bubble and Solar Wind Charge eXchange DXL Mission and Results from DXL Fight 1 Properties of the Local Hot Bubble Summary

Diffuse X-ray Background 3

Diffuse X-ray Background Rosat All Sky Survey (RASS) R12 Band = ¼ keV 4

Diffuse X-ray Background ~40 AU ~100 pc ~2-5 kpc ~z<1 NH NH Local hot Bubble Unresolved point sources Galactic Halo WHIM 5

Solar Wind Charge Exchange IRAS 100 mm X-rays due to charge transfer of solar wind ions (Cravens 1997)

Solar Wind Charge Exchange (SWCX) IRAS 100 mm Heliospheric SWCX: Interaction of Solar Wind with the interplanetary neutrals

Solar Wind Charge Exchange/Local Hot Bubble RASS R12 Band = ¼ keV How much of the diffuse emission is then due to SWCX? Estimates 25%-50% of the emission from SWCX All of the soft emission from SWCX (No Local Hot Bubble?)

SWCX Characterization Spectral signature Temporal signature Spatial signature EBIT data (Courtesy of Greg Brown) F I R 9

SWCX Characterization Spectral signature Temporal signature Spatial signature 11-year modulation due to solar cycle + Time variation due to solar wind activity 10

SWCX Characterization Spectral signature Temporal signature Spatial signature Sun’s velocity 11

Diffuse X-rays from the Local Galaxy (DXL) Sounding rocket mission with 2 large area proportional counters for the study of SWCX and the LHB Grasp at ¾ keV ~ 150 times bigger than XMM Launched from White Sands Missile Range on December 12, 2012 Geometric measurement of the local Diffuse X-ray emission to separate SWCX from LHB

DXL Mission He Focusing Cone (HFC) High helium density region Higher SWCX flux Compare to ROSAT data Separate from LHB emission

Data reduction and analysis DXL should measure an excess emission due to SWCX from the He focusing cone Slow scan region

Data reduction and analysis Solid Lines Red: Helium, DXL Blue: Helium, ROSAT Dotted Lines Red: Hydrogen, DXL Blue: Hydrogen, ROSAT

Data reduction and analysis D12 Band (ROSAT R12, ¼ keV) Cone enhancement

Local Hot Bubble the major contributor to ¼ keV emission Results D12 Band (ROSAT R12, ¼ keV) Galactic plane: 38%±4% (±3% systematic error) Averaged over the whole sky: 27%±3% (±5% systematic error) Local Hot Bubble the major contributor to ¼ keV emission SWCX less than 40% in the ¼ keV band (Galeazzi et al., 2014)

RASS R12 Local Emission (Snowden et al. 1998) Local hot bubble/SWCX RASS R12 Local Emission (Snowden et al. 1998) IRAS 100 mm LHB + SWCX

Local Emission (R1) Local Emission (R2) SWCX (R1) SWCX (R2) LHB (R1) LHB (R2)

LHB R2/R1 Ratio The peak of R2/R1 distribution is shifted from 1.09 to 0.83

LHB Temperature The temperature is peaked at ~0.097 keV with a FWHM of 0.014 keV.

LHB Emission Measure EM range from ~0.8-6.5x10-3 cm-6 pc

LHB Pressure equilibrium Local Interstellar Cloud PT/k~3,200 cm−3 K LHB (pre-SWCX) PT/k~18,000 cm−3 K DXL + New measurements of Local Cavity (Puspitarini et al. 2014):  LHB PT/k~10,600 cm−3 K (ne = 4.68+/-0.47 x10-3 cm-3) Magnetic field outside heliosphere by Voyager 1 (Burlaga & Ness 2014) Magnetic pressure PT/k~7,000 cm−3 K  LIC Pressure PT/k~10,000 cm−3 K Snowden et al. 2014

LHB size and shape 3D model of LHB Galactic Plane Vertical Plane

LHB size and shape Lallement et al. 2014 Galactic Plane

Summary Quantified SWCX contribution LHB predominant in the ¼ keV band 38% SWCX in the ¼ keV band (on plane) Properties of the LHB R2/R1 distribution shifted to small values Temperature peaked at 0.097 keV Generate 3-D structure of LHB

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