Age = Gyr dependent on the detail physics.

Transcription

1 Jiasheng Huang SAO

2 Age = Gyr dependent on the detail physics.

3 Z=1 == D=10.8 x 10^9 light year, 5.9 Gyr since BB Z=3 == D=21.0 x 10^9 light year, 2.2 Gyr Z=5 == D=25.9 x 10^9 ly, 1.2 Gyr Z=7 == D=28.8 x 10^9 ly, 0.8 Gyr Which means that, if its current age is equivalent to 40 years old, we are studying the 4 year old universe at z~5.

4 What does a galaxy look like in the present day Universe?

5 What did a galaxy look like back then?

6 A young one is hot, so appears to be blue. An old galaxy is cold, looks red.

7 The Lyman break technique consists of a set of color criteria to identify star forming galaxies at high redshift through multi band imaging across the 912 Å Lyman continuum discontinuity.

8 Most of Galaxies at 4<z<6 are UV selected, known as LBG (V, R, I dropout): The IRAC photometry permits determining their stellar mass. Z=5.43, V band Dropout Age=400Myr Stellar Mass=10^10 M_solar Mclure et al. (2009)

9 Z=5.7 in GOODS North Mass=10^9~10^10 M_solar Lai et al. (2007)

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13 Marchesini et al. (2010)

14 PI: Dr. Giovanni Fazio, SAO and 49 Co Is The Spitzer Extended Deep Survey (SEDS) is an Exploration Science Program, one of the large scale science programs that were selected to be executed during the Spitzer Space Telescope's Warm Mission. The total time awarded was 2108h. SEDS will provide a unique opportunity to obtain the first complete census of the assembly of stellar mass and black holes as a function of cosmic time back to the era of reionization, yielding unique information on galaxy formation in the early Universe. The survey will also measure galaxy clustering over a wide redshift range, which will provide the critical link between galaxies and their dark matter halos and critical tests of models of early star formation.

15 Co-PIs: Sandra Faber University of California Santa Cruz Harry Ferguson Space Telescope Science Institute

16 Red J K color Red Galaxies at z~2 Red H [3.6] color> Red Galaxies at z~3 J K=2.3 (vega) J K=1.4(AB) at z~2 H [3.6]=1.4 (AB) at z~3 But we did not expect that 4 IRAC sources in GOODS south are not detected in the deep H band images up to H=28 mag. and they have H [3.6]>4.5

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18 [3.6] [4.5]>1 for BDs due to the Methane absorption at 3.6 micron band Our sources have [3.6] [4.5]<0.5, so they are not BDs.

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20 The CO spectroscopy identified this source at z=4.06 Daddi et al. (2010) Wang et al. (2009)

21 We did SED fitting with very wide ranges of extinction parameters, and found: 1. 1 Gyr SSP at z=5.7 with Av=2(Calzetti) 2. Any SP at z~1 with Av=14 (Calzetti) 3. Any SP at z~2 with Av=7 (SMC)

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25 ERS 1 is an X ray source, L(2 8kev)=1.6x10^44 erg/s HR~1 and f_x/f_r>60 Type II QSO ERS 3 is marginally detected at 24, 100, and 250 micron, also at 1.4gHz L_IR=10^13 L_solar and q=2.26 HyperLIRG L_IR<10^13 L_solar for the remaining 3 sources

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28 Implying that they are very massive, ~10^11 M_sol Is it possible to have such a massive galaxy at z~6?

29 The theoretical study (Li et al. 2007) suggested that the host galaxies for these QSOs can have stellar mass of 10^11 M_sol.

30 SMGs are progenitors of these massive galaxies?

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32 We see galaxies having very intensive star formation, We see galaxies being big and old, But theorists still don t believe it!!! In their theory, a galaxy cannot grow that fast To solve this problem, we need a larger space telescope, James Webb Space Telescope, better theory on galaxy formation theory, and most important, young and promising people like YOU!

33 There are red galaxies with H [3.6]>4.5 and H>28 mag. Three possible models can produce such a red color: 1. an old stellar population with Av<2 at z~6. 2. a SED with Calzetti reddening of Av~14 at z~1. 3. a SED with the SMC reddening of Av~7 at z~2 Weak/absent MIR/FIR detection does not support the last two solutions. The 8 micron emission from these galaxies indicates that they are massive, ~10^11 M_sol at z~6. X ray and FIR emission imply their formation mechanism: the merging scenario.

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