Solar Irradiance Observations with LYRA on PROBA2 (An Introduction) I. E. Dammasch, M. Dominique & the LYRA Team Royal Observatory of Belgium LYRA the Large-Yield Radiometer onboard PROBA2

LYRA: the Large-Yield RAdiometer 3 instrument units (redundancy) 4 spectral channels per head 3 types of detectors, Silicon + 2 types of diamond detectors (MSM, PIN): - radiation resistant - insensitive to visible light compared to Si detectors High cadence up to 100 Hz

Royal Observatory of Belgium (Brussels, B) Principal Investigator, overall design, onboard software specification, science operations PMOD/WRC (Davos, CH) Lead Co-Investigator, overall design and manufacturing Centre Spatial de Liège (B) Lead institute, project management, filters IMOMEC (Hasselt, B) Diamond detectors Max-Planck-Institut für Sonnensystemforschung (Lindau, D) calibration science Co-Is: BISA (Brussels, B), LPC2E (Orléans, F)… LYRA highlights

 4 spectral channels covering a wide emission temperature range  Redundancy (3 units) gathering three types of detectors  Rad-hard, solar-blind diamond UV sensors (PIN and MSM)  AXUV Si photodiodes  2 calibration LEDs per detector (λ = 465 nm and 390 nm)  High cadence (up to 100Hz)  Quasi-continuous acquisition during mission lifetime LyHzAlZr Unit1MSMPINMSMSi Unit2MSMPINMSM Unit3SiPINSi

SWAP and LYRA spectral intervals for solar flares, space weather, and aeronomy LYRA channel 1: the H I nm Lyman-alpha line ( nm) LYRA channel 2: the nm Herzberg continuum range (now nm) LYRA channel 3: the nm Aluminium filter range incl the He II 30.4 nm line (+ <5nm X-ray) LYRA channel 4: the 6-20 nm Zirconium filter range with highest solar variablility (+ <2nm X-ray) SWAP: the range around 17.4 nm including coronal lines like Fe IX and Fe X

LYRA pre-flight spectral responsivity (filter + detector, twelve combinations)

LYRA data products and manuals… …available at the PROBA2 Science Center:

Summary: FITS File Structure lyra_ _000000_lev1_***.fits where: *** = met, std, cal, rej, (bst, bca, bre) generally: header + binary extension table(s) extension = header + data (variable length) Lev1 met = HK, STATUS, VFC Lev1 std = uncalibr. irradiance (counts/ms) Lev2 std = calibr. irradiance (W/m²) Lev3 std = calibr. aver. irradiance (W/m²) per line: time, ch1, ch2, ch3, ch4, qual.

Product Definition (“Level 0”, telemetry from PROBA2, internal) Level 1 = full raw data (LY-EDG output) Level 2 = calibrated physical data (LY-BSDG output) Caution: preliminary status. Require versioning. Level 3 = processed products (e.g. averages) Level 4 = plots of products Level 5 = event lists (optionally with plots)

Further Data Products… …“Level 4”, “Level 5” (from preliminary to current status):

before

now

before

now

before

now

monthly overview

interval around a flare (-1h,+2h)

LY-TMR: State of the data processing pipeline LY-EDG LY-BSDG Telemetry packets “Lev0”: Raw data (in counts) Lev1: Engineering data (in counts/ms) fits Lev2,Lev3: Calibrated data (in W/m²) Other tools Higher level data products Current stateIn the future Not distributed After each contact After each contact After each contact After each contact Plots regular, Flare list irregular systematic

First results (even before opening covers)

Aurora Oval  Perturbations appearing around 75° latitude  2-3 days after a CME, flare...  Associated to geomagnetic perturbations Spacecraft maneuvers SAA

First Light acquisition (06 Jan 2010)

Aeronomy  Occultations: Study atmospheric absorption; high temporal resolution needed  Input for atmospheric models: NRT and calibrated data needed

Flares LYRA observes flares down to B1.0 LYRA flare list agrees with GOES14&15 Flares are visible in the two short-wavelength channels Exceptionally strong and impulsive flares are also visible in the Lyman- alpha channel (precursor) Example: C4.0 flare, 06 Feb 2010, 07:04 UTC

M2.0 flare, 08 Feb 2010, 13:47 UTC

Comparison with GOES flare Example: M1.8 flare, 20 Jan 2010, 10:59 UTC

Comparison with GOES flare Example: C5.4 flare, 15 Aug 2010, 18:30 UTC

LYRA flare size LYRA background-subtracted flux in Zr (channel 2-4) LYRA observes all GOES flares in both Al and Zr channels Initially also Lyman-alpha contribution for strong impulsive flares Similar onset, different peak times in different pass bands Good correlation to GOES, better temporal resolution

GOES vs. LYRA proxies (new website under construction)

Example: M1.1 flare, 28 Feb 2011 start to rise at same time parallel in impulsive phase GOES peaks earlier LYRA decreases slower linear factor in pure flare irradiance

Flare components ch2-3 = SXR+EUV “SXR”: emission with log(T)>7 “EUV residual”: emission with 6<log(T)<7 “little bump”: emission with log(T)<6 Compare with SDO/EVE:

Thermal evolution plot based on: solar spectra observed by SDO/EVE contribution functions from the CHIANTI atomic database

Sun-Moon eclipse …demonstrating the inhomogeneous distribution of EUV radiation across the solar surface

Eclipses as seen with SWAP swap_eclipse_15Jan2010.mp4 swap_eclipse_11Jul2010.mp4

And we have a fifth channel at 17.4nm called SWAP (using “SWAVINT”)

Jan - Sep 2010 SWAVINT and LYRA look quite similar LYRA shows flares in addition to EUV

SWAP and LYRA observing together _proba2_movie.mp4

July 2010: LYRA vs. ESP (SDO/EVE)

July 2010: LYRA vs. GOES

Next steps Cross-calibration (internal/external) Produce calibrated data automatically (OK, but regular updates necessary) Publish first results (in process) Advertise data products Get another extension from ESA (2012: OK)

How to be involved? Scientists are welcome to use PROBA2 data propose special observation campaigns Guest Investigator Program welcomes proposals for dedicated (joint) observations in the frame of a science project: Funds available for a stay at PROBA2 Science Center Scientist can take part in the commanding of the instruments Will gain expertise in the instrumental effects Next announcement (for ): May 2011 Proposal deadline and selection: June 2011 First visits: September 2011 onwards

Calibration 2010 according to TIMED/SEE

Calibration – Problem: 2010 according to LYRA

Solution – Start with “First Light”

… fit the degradation …

… and add it Plausibility: Artifacts in channels 1 and 2 Non-degenerated SXR in channels 3 and 4

To be continued