Introduction to and methods of SPACE-based observational astronomy 1 st MAGPOP School (Budapest, Aug ) Armando Gil de Paz (Universidad Complutense de Madrid) 3 rd lecture

Scheme 1 st MAGPOP School (Budapest, Aug ) James Webb Space Telescope (JWST) IUE, IRAS, ISO data Past Missions: Future: Space-based Astronomy Tools and Science: Use of Space-based data Synergy with ground-based data (e.g. HST-Keck/VLT, JWST-ALMA) Today’s lecture

Past missions: IUE 1 st MAGPOP School (Budapest, Aug ) Partners: Joint NASA, ESA, PPARC mission. 19 years operational (from its launch in 1978 to 1996). Orbit: Geosynchronous over Atlantic. Telescope: 45-cm f/15 Ritchey-Chretien Cassegrain. Instrument: Echelle spectrograph ( ÅÅ, ÅÅ) with 3” and 10”x20” apertures and high (0.1 Å) and low-resolution (6 Å) modes. Image quality: 2” Cameras: SWP, LWP (short and long-wavelength prime), & SWR, LWR (redundant cameras). Archive: spectra extracted from IUE images. Maintained at Villafranca tracking station (spectra processed using ESA’s INES software) at A copy is also available through MAST although using an older pipeline version. IUE summary:

IUE: Archival Data 1 st MAGPOP School (Budapest, Aug )

Past missions: IRAS 1 st MAGPOP School (Budapest, Aug ) Partners: Joint project of the US, UK, and the Netherlands. Launched in January Orbit: Sun-synchronous near-polar (99 o ). Telescope: 57-cm f/9.6 Ritchey-Chretien. Instruments: Survey Array, CPC, LRS. IRAS summary: IRAS focal plane

IRAS: Archival Data 1 st MAGPOP School (Budapest, Aug )

Past missions: ISO 1 st MAGPOP School (Budapest, Aug ) Partners: ESA with the participation of ISAS & NASA. Built by Aerospatiale (now Alcatel). Launched by an Ariane IV in November Scientific observations were carried out between Feb’96- Apr’98. Orbit: 24h-period high orbit inside and outside the Van Allen belts. Detectors unusable inside the belts.

ISO: Instruments 1 st MAGPOP School (Budapest, Aug ) ISOCAM: Two imaging channels with 32×32 arrays operating between um & 4-17 um and 21 filters (11 SW+10 LW). LWS: It covered the range um with R ∼ 200 (R~10000 using Fabry-Pérot etalons). ISOPHOT: Consists of three subsystems: ISOPHOT-C, with two photometric cameras covering the range um. ISOPHOT-P, a multi-band, multi-aperture um. ISOPHOT-S, a dual grating spectro- photometer with R~90 in two simultaneous bands (2.5-5um & 6-12um). SWS: It covered the range um with R= (25000 with FP etalons). M51 (ISOCAM LW um) PHT-S SWS LWS Points: PHT-C/P

ISO: Archival Data 1 st MAGPOP School (Budapest, Aug )

Future missions: JWST 1 st MAGPOP School (Budapest, Aug ) James Webb Space Telescope: Summary Developed by an industrial consortium under NASA’s supervision in collaboration with ESA (mostly for instrument development). High orbit around the L2 Sun-Earth Lagrange point. Launch ~2013 by an Ariane V rocket.

JWST: Instruments 1 st MAGPOP School (Budapest, Aug )

SPACE-based Astronomy Tools & Science (just a few examples) 1 st MAGPOP School (Budapest, Aug )

Space-based Astronomy T&S 1 st MAGPOP School (Budapest, Aug ) PSF photometry: Critical for crowded fields, Supernova photometry, diffraction- limited images. Not for use with -even marginally- resolved sources. Procedure: Determine PSF empirically from field stars, analytically (2D Gaussian, Lorenzt, Moffat), or Hybrid. Minimize: ACS PSF NICMOS PSF MIPS PSF

1 st MAGPOP School (Budapest, Aug ) PSF-photometry software: ROMAFOT, STARMAN, DAOPHOT (Stetson 1987), DoPHOT, HSTPHOT Alternatives: Aperture photometry, Sextractor, TFIT PSF-photometry science (HST CMD of nearby galaxies): Gallart et al. (1999) daophot + addstar + daophot Space-based Astronomy T&S

1 st MAGPOP School (Budapest, Aug ) Low background (Poisson statistics): mean ≠ median ≠ mode In extreme cases (FUV) most background pixels are zero. GALEX FUV flux vs. HI (texp=100s) GALEX FUV flux vs. HI (texp=1500s) GALEX FUV flux vs. HI (texp=30000s) Space-based Astronomy T&S Braine et al. (2006, in prep.)

1 st MAGPOP School (Budapest, Aug ) New windows: UV IRX-  law: Since the intrinsic UV slope is approx. constant for continuous SF or smoothly-evolving SF histories, the measured UV slope provides a good estimate of the UV extinction. Good for not heavily extincted objects. In highly attenuated objects the UV-to-TIR flux ratio can be used. Space-based Astronomy T&S SFR: The UV luminosity (once corrected for extinction) is a good Star Formation Rate tracer (via IMF). Sensitive to very low-levels of SF at low metal abundances (e.g. extended UV). UV upturn: Unexpected FUV rising flux in evolved stellar populations. First discovered in the nucleus of M31 by the OAO. Emission from BHB stars is suspected. The slope of the integrated CMD is opposite to that seen in the optical. M83 NGC1512 GALEXOpticalHI 21cm GALEXOpticalHI 21cm Gil de Paz et al. (2006); IRX-beta (Meurer et al. 1995, 1999) Favored extinction law Gil de Paz et al. (2006) E/S0 Boselli et al. (2005) Z Roussel et al. (2005)

1 st MAGPOP School (Budapest, Aug ) New windows: IR UV-to-TIR ratio: The best estimate of the UV extinction. It is almost independent of dust properties, geometry, and SFH (Buat et al. 2005). Space-based Astronomy T&S SFR: FIR emission due to dust heated by young hot stars: Good measure of the SFR. Advantage: It is extinction free. Disadvantage: Dust also heated by optical photons, especially a longer wavelengths (cooler dust). Thus, the 24 um luminosity provides the best correlation with extinction-corrected H  -based SFRs (Calzetti et al. 2006: Pérez- Gonzalez et al. 2006). MIR diagnostics: The study of the MIR provides important clues on:(1) Formation and excitation conditions of PAHs (2) The relevance of stochastically-heated VSGs (3) The chemical composition of evolved stellar populations (e.g. Silicates feature).

1 st MAGPOP School (Budapest, Aug ) Synergy with ground-based astronomy Nearby Galaxies: Spitzer + GALEX imaging combined with ground-based corollary data. Some examples: Roussel et al. (2005) on NGC300 Dale et al. (2006) on 75 SINGS objects. Perez-Gonzalez et al. (2006) on M81 Thilker et al. (2006) on NGC7331. Radial and small-scale properties of extinction, dust temperature, SFR; multi-wavelength SEDs for local templates. Dependence of dust attenuation properties with the clusters’ evolutionary stage. NGC300 Roussel et al. (2005)

1 st MAGPOP School (Budapest, Aug ) Synergy with ground-based astronomy Cosmological redshift surveys (HST-Keck/VLT): HST is not optimized for measuring redshifts of faint distant galaxies (just a 2.5m!) Redshifts have traditionally come from 8-10m telescopes such as Keck, VLT, Gemini… Unfortunately, most sources in deep imaging surveys with HST (HDF, UDF) are well beyond the spectroscopic limit (I AB ~25- 26). Objective of new 30-m class telescopes (TMT,GMT,OWL). photo-z 6m

1 st MAGPOP School (Budapest, Aug ) Synergy with ground-based astronomy Future surveys (JWST- ALMA-30m synergy): ALMA will provide an unprecedented sample of very distant galaxies thanks to the negative K-correction. Targeted JWST programs will allow deriving rest-frame optical properties with superb resolution. 30m-class telescopes should provide redshifts for ALMA sources with faint molecular-line emission. … and (in some cases) in 3D using IFUs!

1 st MAGPOP School (Budapest, Aug ) The End Some notes on the CD-ROM content & Proposal-making practical session