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Lhistoire de la formation stellaire dans lunivers avec les ELT et ALMA.

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Présentation au sujet: "Lhistoire de la formation stellaire dans lunivers avec les ELT et ALMA."— Transcription de la présentation:

1 Lhistoire de la formation stellaire dans lunivers avec les ELT et ALMA

2 Un exemple de distribution spectrale dénergie GALEX-ELAIS-SWIRE nécessité de coupler UV-optique et FIR-submm

3 La contribution de lémission des poussières croît avec z Z= 0, 0.3, 0.5, 0.7 & 1.0 Plus grande evolution en FIR quen UV mais forte évolution des galaxies de faible luminosité en UV

4 Comment mesurer le SFR en UV-optique? continuum UV ou raies démission

5 Mesure du continuum: Pour d é tecter des galaxies à z=7 avec L=L * et m AB = < L/L * < 0.1 et 31.2 < m AB < 33.7

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8 Comparaison ELT/JWST JWST commence à 1 m

9 ALMA: Un exemple de détection a haut redshift As galaxies get redshifted into the ALMA bands, dimming due to distance is offset by the brighter part of the spectrum being redshifted in. Hence, galaxies remain at relatively similar brightness out to high distances. M82 from ISO, Beelen and Cox, in preparation

10 ALMA Deep Field Poor in Nearby Galaxies, Rich in Distant Galaxies Nearby galaxies in ALMA Deep Field Source: Wootten and Gallimore, NRAO Distant galaxies in ALMA Deep Field

11 Hubble Deep Field Rich in Nearby Galaxies, Poor in Distant Galaxies Nearby galaxies in HDF Source: K. Lanzetta, SUNY-SB Distant galaxies in HDF

12 ALMA Redshift Survey 4×4 Field Step 1 A continuum survey at 300 GHz, down to 0.1 mJy (5σ). This requires 140 pointings, each with 30 minutes of observation, for a total of 3 days. Such a survey should find about sources, of which sources will be brighter than 0.4 mJy. This field is twice the size of the HDF. Image 3000x3000 pixels x 1024 frequencies. Step 2 A continuum and line survey in the 3 mm band down to a sensitivity of 7.5 mJy (at 5σ). This requires 16 pointings, each with 12 hours of observation, so a total of 8 days. The survey is done with 4 tunings covering the GHz frequency range. Image 1000 x 1000 pixels x 4096 frequencies. The 300 to 100 GHz flux density ratio gives the photometric redshift distribution for redshifts z > 3-4. For expected line widths of 300 km/s, the line sensitivity of this survey is 0.02 Jy.km/s at 5σ. Using the typical SED presented earlier this should detect CO lines in all sources detected in Step 1. At least one CO line would be detected for all sources above z = 2, and two for all sources above z = 6. The only ``blind'' redshift regions are and Step 3 A continuum and line survey in the GHz band down to a sensitivity of 50 mJy (at 5σ). 8 adjacent frequency tunings would be required. On average, 90 pointings would be required, each with 1.5 hours, giving a total of 6 days. Together with Step 2, this would allow detection of at least one CO line for all redshifts, and two lines for redshifts greater than x2000 pixels by 8192 frequencies. N.B. Three data products of substantial complexity to assimilate.

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14 Comparaison avec une galaxie plus « normale » NGC 4414 (J. Braine) 0.1 mJy ne sera peut- être pas une limite assez profonde Le champ dALMA nest pas très favorable aux surveys

15 Un instrument submm (type SCUBA) sur les ELT serait plus efficace pour un survey (projet SCELT-SCOWL)

16 SCOWL sur OWL et ALMA : quelques comparaisons préliminaires Matrice pixels de 1 arcsec 2 m 0.17 mJy en 1h à 350 m Survey grande surface Survey grande surface 1 deg 2 1 deg 2, 5 = 0.1 mJy 39 nuits (1nuit = 12h) Survey profond 10 arcmin 2, 5 = 0.02 mJy 3 nuits ALMA SCOWL

17 En résumé: La mesure statistique de lhistoire de la formation stellaire nécessite des grands champs et peu de résolution spectrale ELT: SFR jusquà z 5-7 puis compétition avec JWST. ELT meilleur en NIR, couvre le visible ALMA: petit champ, difficile de faire de grands surveys, FIR-submm sur un ELT plus adapté ELT vis-NIR et ALMA très adaptés aux études détaillées et physiques cf. présentations de M. Gérin et F. Hammer

18 Un instrument submm sur un ELT sera plus efficace quALMA pour des grands relevés

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21 SPICA The Cosmic Star Formation Density : Building a Sample of 0.5 z < 3.0 Lyman Break & Star-Forming Galaxies to compute Total Star Formation Rates Véronique Buat & Denis Burgarella Obs. Astronomique Marseille Provence LAM

22 General Objectives Multi- low-to-moderate R to study galaxies and their properties (z) : Dust Content Star Formation (rate, density)

23 Instrumental Assumptions Detection limit over the band m is taken to ~ 50 Jy in 1h and at 5 ( ) )= 5 cm -1 R = Wavelength ( m) Detection Limit 5, 1h ( Jy)

24 Confusion effects Several confusions : –Cirrus emission –Extragalactic sources Latter will be dominant for large telescopes like Herschel and SPICA (Kiss, Klass & Lemke 2005 A&A 430, 343) Dole et al. (2004 ApJS 154, 93) compute total confusion limits ( ) for SPICA

25 Back to the original paper by Helou & Breichman (1990, In ESA, From Ground-Based to Space-Borne Sub-mm Astronomy p. 117) Decomposition of confusion limit into several components: 1.Telescope & Detector 2.Bright cirrus 3.Galaxies (1) valid for a 4-m passively cooled telescope in Earth orbit (not SPICA) (1) (2) (3)

26 Lets go back to Science

27 In 1h, we can detect Lyman Break z ~ 1

28 LBGs (30M sun /yr) > 2 not detected in 1h ( ) but detected in 100h ( ) and even at z = 3 for SFR IR > 30M sun /yr ( ) Takeuchi et al. (2005) ALMA

29 Proposition of Program for SPICA/ESI Title: Evaluating the Total (UV + FIR) Star Formation Density Field of view : as large as possible but about 2 x 2 seems reasonable Wavelength range : 40 to 100 m Spectral resolution : 10 to 50 Spatial resolution : diffraction limited Need for SPICA : no existing facility can observe in the FIR down to ~ 10 M sun / yr over a large field of view

30 Et voilà !


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