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Intergalactic Medium: Discussion on Lyman-alpha Forest Quasar Emission Lines

This report discusses the Lyman-alpha forest quasar emission lines and their implications for the intergalactic medium. The importance of feedback mechanisms, metal enrichment, and the study of high-redshift sources is explored.

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Intergalactic Medium: Discussion on Lyman-alpha Forest Quasar Emission Lines

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  1. R Srianand IUCAA, Pune & Tom Theuns Institute for Computational Cosmology, Durham, UK Department of Physics, Antwerp, Belgium Intergalactic Medium: Report on discussion and presentation of parallel meeting

  2. Lyman alpha forest Quasar To Earth Emission lines from the Quasar Hydrogen absorption due to galaxy Heavy element absorption DLA Lyman limit Observed wavelength (Å) Srianand & Theuns: Intergalactic Medium Courtesy John Webb

  3. The importance of “feedback”: galaxy-wide winds? M82 Springel Srianand & Theuns: Intergalactic Medium

  4. Absorption lines of several (low-ionization state) transitions are off-set from the velocity of the stars by many 100s of km/s in cB58, a Lyman-break gal@z=3 Pettini et al Srianand & Theuns: Intergalactic Medium

  5. Adelberger et al 03 Srianand & Theuns: Intergalactic Medium

  6. Can feedback implementation explain observed metals? Simulation with metal enrichment due to galactic winds appears to reproduce the observed CIV-HI scatter Theuns et al 2001 Srianand & Theuns: Intergalactic Medium

  7. Srianand & Theuns: Intergalactic Medium

  8. Probing reionisation with the IGM Lya forest becomes very dense at z>6: end of reionisation? WMAP: zreion=15 Srianand & Theuns: Intergalactic Medium

  9. Clustering of sources means ionised bubbles large (many Mpc) Find Lya emitters in them? Tom Abel Ciardi et al. Srianand & Theuns: Intergalactic Medium

  10. IGM metal enrichment: z=3-5 and z>5 Low z < 5: can study neutral H (Lya forest) Higher z: study metals to infer ionisation state. Transitions detectable in the NIR: C IVC IIOI Si I for z< 12.5 14.7 15.1 15.7 (l <2.1m) Srianand & Theuns: Intergalactic Medium

  11. High z>7 Sources: GRB mean afterglow fluxes 1.5 to 0.05 µJy at z =10, 1 to10 days after explosion (KAB=23.6 to 27). Need high resolution R=4 104 and S/N>50 to detect individual lines. (NIR) – detection limits: 4m J limit for R=10 4& S/N=50 N(C II)min=4x10 12 cm-2 N(OI)min =1x 10 13cm-2 ! metal enriched sites only clustering signatures down to 30 km / s possible for bright sources like the brightest GRBs JB Srianand & Theuns: Intergalactic Medium

  12. High z>7 Other point sources: population III SNe (pair instability - M = 140-260 M ) : KAB= 25 at z = 10-15 Possible time lag of weeks between discovery and ELT spectroscopy QSOs too faint? / do not exist? High S/N, high R, point sources Srianand & Theuns: Intergalactic Medium

  13. High z>7 Requirements: intermediate/high resolution spectroscopy – NIR, R=2000, S/N up to 100 (CCDs), optimal with OH suppressor multiple IFUs over a total FoV of several arcmin 2 QSOs + the brighter LBGs at z > 7 (mAB= 27-28) brightest sources only observable with 30 m ELTs – NIR, R=10000, S/N up to 100 (CCDs) : single target average GRBs + population III SNe at z > 7 (mAB=25) Find sources using JWST/dedicated ground/space based telescopes Srianand & Theuns: Intergalactic Medium

  14. Integrating from log d = -0.5 - +2.0 gives (QG): Lower z<7 Absence (?) of metallicity evolution JS et al. (2003) Not all metals seen? At z<1 in clusters. Need many transitions to constrain UV shape Srianand & Theuns: Intergalactic Medium

  15. Lower z<7 • IGM at z=2-5(10) : very high resolution spectroscopy : single target – optical: R=40000, S/N=1000 up to 10000 brightest GRBs (S/N=100) at z > 7 (lag=1 day, mAB= 20) and bright QSOs at z=2-5 (mAB= 16-17) Blue sensitive, and large wavelength coverage OVI(l1030) CVI (l1550) observed wavelength range 3030 – 9300 to constrain ionisation corrections Srianand & Theuns: Intergalactic Medium

  16. Science at z<5: IGM/galaxy interactions Srianand & Theuns: Intergalactic Medium

  17. Science at z<5: IGM/galaxy interactions Probing the spatial correlation of galaxies and metals using multiple sightlines Srianand & Theuns: Intergalactic Medium

  18. Probe IGM with multiple sightlines, including fainter sources Current: mean CIV foreground galaxy absorption as function of impact parameter 0.2” 1-5” 5-10” Srianand & Theuns: Intergalactic Medium

  19. Future: • Detect CIV in individual galaxies with good redshifts • Use bright LBGs, and fainter QSOs as beacons too. Srianand & Theuns: Intergalactic Medium

  20. Lower z=[2,5] • Requirements: intermediate and high resolution spectroscopy • – Optical/NIR R=2000-5000, S/N up to 100 for z-determination of 0.01L* LBGs (MOS). Multiple IFUs over a total FoV of several arcmin 2 around L* LBGs and QSOs. • Optical high R=50000, S/N=100 for IGM spectroscopy of brighter LBGs faint QSOs. See TMT science priorities Srianand & Theuns: Intergalactic Medium

  21. Molecules at High z Srianand & Theuns: Intergalactic Medium

  22. Molecules at High z • H2 allows one to probe starformation in Galaxies. • S/N= 500-1000, R = 45,000 and l>3400, M<22 QSOS will allow • -the detection of CO and HD. CO/H2 ratio. • -Omega_baryon from HD/H2. • -Tcmb (z) • -variation of dm/m. (m=me/mp) Srianand & Theuns: Intergalactic Medium

  23. Fine-structure excitation of C I: CMB ex CI* / CI Temperature Srianand & Theuns: Intergalactic Medium

  24. Summary of discussion • Priorities • Major Technical Constraints: • Spatial Resolution • Contrast Ratio • Wavelength Range • Field of View • Atmospheric Turbulence Compensation • Wind Forces • Instrumentation and Telescope Srianand & Theuns: Intergalactic Medium

  25. Summary of discussion Reionisation: metals at z>7, Ly a emitters – NIR, R=2000, S/N up to 100 – NIR, R=10000, S/N up to 100 (CCDs) : single target Galaxy/IGM correlations at z<5. UV-escape from LBGs - optical/NIR: R=2000-5000, S/N=100 MOS (faint QSOs, LBGs) - optical: R=40000, S/N=1000 up to 10000 Blue sensitive, l = 3030 – 9300 A (single bright source) Many small progs, can be started early stages of construction 8m class telescopes to find LBGs, Ly a emitters Srianand & Theuns: Intergalactic Medium Find sources using JWST/dedicated ground/space based telescopes

  26. Fundamental Physics Kinematics of the expansion of the Universe: CODEX, variation Tcmb(z) using CI. Variation of a: CODEX, but with larger l range to probe same transitions at different redshifts SKA will measure 21cm in DLAs, l21 depends on a2m/G p, H2 will probe m, other transitions a. Srianand & Theuns: Intergalactic Medium

  27. Summary: – NIR, R=2000, S/N up to 100 (MOS) – NIR, R=10000, S/N up to 100: single target - optical/NIR: R=2000-5000, S/N=100 MOS - optical: R=40000, S/N=1000 up to 10000: single targer Blue sensitive, l = 3030 – 9300 A (large l range Codex) Flexible instruments Srianand & Theuns: Intergalactic Medium

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