Physics of the Formation and Evolution of Galaxies Report from the High-z Working Group. Tsutomu T. TAKEUCHI (Nagoya University) Hiroyuki HIRASHITA (ASIAA ) Shuichiro YOKOYAMA (Nagoya University) and members of the high- z working group.
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Tsutomu T. TAKEUCHI
Hiroyuki HIRASHITA (ASIAA)
Shuichiro YOKOYAMA (Nagoya University)
and members of the high-z working group
Japan SKA Workshop 2010, 4-5 Nov., 2010, NAOJ, Mitaka, Japan
Galaxy Evolution with a Wideband Receiver at 1-15 GHz
Twenty-twomembers in the mailing list (from students to senior researchers with wide range of expertise).
Representative: Hiroyuki HIRASHITA (ASIAA,Taiwan)
Core members: Tsutomu T. TAKEUCHI (Nagoya U.)
Daisuke IONO (NAOJ)
Shinki OYABU (Nagoya U.)
The high-z working group is open to anyone.
If you would like to participate in this working group, please let us know.
Here we concentrate on a frequency range of 1-15 GHz,possibly contributed from Japanese instrumentation.
H2O maser: 22 GHz (z > 0.5)
NH3lines: 23.7 GHz (z > 0.5)
H I emission line: 1.4 GHz (z < 0.4)
CO absorption lines: z > 6.7
Possible important sciences for lower frequencies:redshifted H I: 1.4/(1 + z) GHz for cosmology (Part II)
In this talk, direct contributions from the WG members are indicated by .
2.1 H2O maser (22 GHz; z > 0.5)
Two detections so far for z > 0.5
Barvainis & Antonucci (2005): SDSS J08043+3607 @ z = 0.66
VioletteImpellizzeri et al. (2008): MG J0414+0534 @ z = 2.64
z = 2.64 (lensed: factor 35)
100 m Effelsberg
n(H2) > 107 cm-3
T > 300 K
associated with AGN
environments (accretion disk or AGN jets)
2.2 NH3 lines (23.7 GHz; z > 0.5)
Level population of various rotational states
⇒We can trace the excitationtemperature.
Interesting viable way to explore the state of the ISM in high-z galaxies.
2.3H I emission (21 cm; z < 0.4)
Baryonic Tully-Fisher relation (BTF) (McGaugh et al. 2000)
Important empirical relation connecting the halo (dynamical) mass and baryon content. Especially important for very late type galaxies (H I-dominated in baryonic content).
HIPASS result (Meyer et al. 2008):
which is steeper than luminosity TF. However, it is still too shallow.
Some recent works showed a possible downward deviation from a single power law.
2.3H I emission (21 cm; z < 0.4)
The “extended” BTF (McGaugh et al. 2010)
The slope becomes steeper from the largest to the smallest structures (clusters: violet symbols, giant galaxies: blue symbols, and dwarf spheroidals: red symbols).
⇒ Possible effect of feedback?
However, gaseous dwarfs are missing on this plot.
Toward lower H I masses!
2.4 CO absorption lines (z > 6.7)
Molecular absorption lines in -ray burst afterglows
Probe of physical and chemical conditions in high-zISM.
1-15 GHz continuum ~ 0.1-1 mJy at tobs~10 days for z = 5-30
t vs. n, Z in protostellar clouds
expected afterglow spectra
Inoue, Omukai, & Ciardi (2007)
Synchrotron from supernova remnants
⇒ Related to star formation activity
> 15/(1+z) GHz is favorable to avoid f-f absorption in dense (> 103cm-3) regions
Potentially interesting area for very young galaxies
(5) Radio continuum from galaxies
Expected observed-frame 1.4 GHz flux density for galaxies of various IR luminosities assuming the FIR–radio correlation (qIR = 2.64) is shown (Murphy 2009).
N.B. Cosmic ray electrons lose energy through inverse Compton scattering of the CMB, and nonthermal continuum is strongly suppressed at high-z.
To detect moderate LIRGs at z = 4-10, the detection limit of 10 nJy is required.
Merits of wide frequency range
N.B. a special imaging technique to deal with a large dynamic range should also be developed.
⇒ Suggestions are welcome!
Exploring Non-Gaussianity in the Primordial Perturbation with 21-cm Line Tomography
CMB, LSS observations
⇒ nature of primordial fluctuations
⇒ physics of the early Universe.
Current observations predict that the primordial fluctuation has almost Gaussian statisticsas expected from the linear perturbation theory.
Now the primordial non-Gaussianity is hitting the limelight of cosmologists (Komatsu & Spergel 2001, and many others!)
Non-Gaussianity is a very broad category and until recently no systematic way to investigate it was known , in spite of enormous theoretical effort made in 90’s.
The situation has dramatically changed by the introduction of the nonlinearity parameter, fNL. The primordial perturbation F is described as
Non-zero fNL gives
Higher order contribution in the power spectrum (2-point correlation function.)
Leading order contribution in the bispectrum (3-point correlation function) !!
Current observational limit from WMAP 7-year data
(central value ~40 …??)
Future CMB observations: Planck
2.1 The 21-cm signal from neutral hydrogen gas
21 cm hydrogen line: 1.4 GHz
⇒ 1.4/(1+z) GHz @redshift z
z = 100 – 30 ⇔ 14 MHz – 47 MHz
: spin temperature of H I.
: optical depth for the hyperfine transition.
Fluctuation in the brightness temperature
density fluctuations of neutral gas
Loeb and Zaldarriaga (2004)
2.2 Bispectrum of the CMB temperature fluctuations
The bispectrum (Fourier transformed 3-point correlation) of the CMB brightness temperature map can be used to estimate fNL efficiently (Cooray 2006).
Bandwidth: 1 MHz
Frequency: 14 - 45 MHz
(z ~ 100-30)
Multipole: lmax~ 105
TTT has been supported by Program for Improvement of Research Environment for Young Researchers from Special Coordination Funds for Promoting Science and Technology commissioned by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.