physics of the formation and evolution of galaxies report from the high-z working group
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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. - PowerPoint PPT PresentationTRANSCRIPT
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
Japan SKA Workshop 2010, 4-5 Nov., 2010, NAOJ, Mitaka, Japan
Part I: Galaxy Evolution with a Wideband Receiver at 1-15 GHz
1. Overview of the Working Group2. Possible Observations3. Requirement for the Instruments4. Summary of Part I
Part II: Exploring Non-Gaussianity in the Primordial Perturbation with 21-cm Line Tomography
5. Primordial non-Gaussianity 6. The 21-cm Tomography7. Summary of Part II
Outline
Twenty-two members 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.
1. Overview of the Working Group
Here we concentrate on a frequency range of 1-15 GHz, possibly contributed from Japanese instrumentation.
(1) H2O maser: 22 GHz (z > 0.5)(2) NH3 lines: 23.7 GHz (z > 0.5)(3) H I emission line: 1.4 GHz (z < 0.4)(4) CO absorption lines: z > 6.7(5) Continuum
2. Possible Observations
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 .
100 m Effelsberg z = 2.64 (lensed: factor 35)104 L☉ (lens-corrected)
Two detections so far for z > 0.5Barvainis & Antonucci (2005): SDSS J08043+3607 @ z = 0.66Violette Impellizzeri et al. (2008): MG J0414+0534 @ z = 2.64
EVLA
n(H2) > 107 cm-3
T > 300 Kassociated with AGNenvironments (accretion disk or AGN jets)
2.1 H2O maser (22 GHz; z > 0.5)
Emission is very weak ⇒ Absorption may be better.
An example for the detection of absorption for a lensed quasar at z = 0.9 (Henkel et al. 2008)
Level population of various rotational states
⇒ We can trace the excitation temperature.
Interesting viable way to explore the state of the ISM in high-z galaxies.
2.2 NH3 lines (23.7 GHz; z > 0.5)
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.
2.3 H I emission (21 cm; z < 0.4)
4VM B
The “extended” BTF (McGaugh et al. 2010)
Toward lower H I masses!
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.
2.3 H I emission (21 cm; z < 0.4)
Inoue, Omukai, & Ciardi (2007)
Probe of physical and chemical conditions in high-z ISM.1-15 GHz continuum ~ 0.1-1 mJy at tobs~10 days for z = 5-30
Molecular absorption lines in -ray burst afterglows
t vs. n, Z in protostellar clouds
expected afterglow spectra
2.4 CO absorption lines (z > 6.7)
Radio
Condon (1992)Synchrotron from supernova remnants ⇒ Related to star formation activity
> 15/(1+z) GHz is favorable to avoid f-f absorption in dense (> 103 cm-3) regions
2.5 Continuum
Synchrotron
Dust
Free-free
M82
(1) H2O maser: peak 3 mJy (z = 2.64) with lensing factor 35 (Violette Impellizzeri et al. 2008) → 0.1 mJy
(2) NH3 → determined by the continuum level and S/N. Continuum ~ Jy (quasar) and S/N = 100 → 10 mJy
(3) H I emission: down to H I mass = 103 M☉(~ baryonic mass of dSph) → at 3 Mpc; 50 Jy (M/103M☉)/(v/10 km-s) (extended)
(4) The radio SED models suggest that absorption with ~ 1 in a GRB can be observed with a Jy-level detection limit.
3. Requirement for the Instruments
(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.
(1) Lines• Can trace the evolution along redshift z• Can determine the excitation temperature and
density (e.g. CO(1-0) and CO(2-1))
(2) Continuum• Can receive a larger number of photons
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!
(1) Working group member is now composed of 22 people but should be expanded.
(2) Possible sciences for 1-15 GHz area. Lines (H2O maser, NH3 lines, H I, CO; depending on z)b. Continuum (Radio-FIR relation → collaboration with
ALMA)c. New ideas!
(3) Requirements:a. Sensitivities of m-10 nJy.b. Imaging techniques should also be developed.
4. Summary of Part I
1. Primordial Non-Gaussianity
Now the primordial non-Gaussianity is hitting the limelight of cosmologists (Komatsu & Spergel 2001, and many others!)
CMB, LSS observations ⇒ nature of primordial fluctuations ⇒ physics of the early Universe.
• amplitude ⇔ energy scale of inflation• scale-dependence ⇔ form of the potential of inflaton• statistics⇔ standard inflation scenario?
Current observations predict that the primordial fluctuation has almost Gaussian statistics as expected from the linear perturbation theory.
1.1 Basics
2Gauss
2GaussNLGauss )()( xxfxx
Non-zero fNL gives1. Higher order contribution in the power spectrum (2-point
correlation function.)2. Leading order contribution in the bispectrum (3-point
correlation function) !!
1.2 Parameterization with fNL
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
Current observational limit from WMAP 7-year data
(central value ~ 40 …??)
Future CMB observations: Planck
CL) (95% 7410 localNL f
5NL f
Theoretical predictions: • Single, slow-roll inflation model (standard inflation scenario)
( = order of slow-roll parameters ) • Non-slow-roll model, multi-scalar model
)01.0(NL Of
)11.0(NL Of
2. The 21-cm Tomography
21 cm hydrogen line: 1.4 GHz ⇒ 1.4/(1+z) GHz @redshift z
i.e.,z = 100 – 30 ⇔ 14 MHz – 47 MHz proton
electron
photon
Brightness temperature: spin temperature of H I.: optical depth for the hyperfine transition.
Fluctuation in the brightness temperature
density fluctuations of neutral gas
primordial fluctuations Loeb and Zaldarriaga (2004)
2.1 The 21-cm signal from neutral hydrogen gas
The bispectrum (Fourier transformed 3-point correlation) of the CMB brightness temperature map can be used to estimate fNL efficiently (Cooray 2006).
2.2 Bispectrum of the CMB temperature fluctuations
3D data!!
Optimistic predictionBandwidth: 1 MHzFrequency: 14 - 45 MHz
(z ~ 100-30) Multipole: lmax ~ 105 ⇒
CMB observations Planck
z1
2D data
(1) Non-Gaussianity in the primordial fluctuation is crucial to constrain the type of inflation.
(2) The nonlinearity parameter fNL is the key tool to explore the non-Gaussianity. Standard inflation model predicts fNL = O(0.01), while multi-scalar or non-slow-roll inflation scenarios predict fNL > O(0.1).
(3) The 21-cm line tomography works as a promising method to determine fNL. If we achieve DfNL ~ 0.01, we can distinguish inflation models finely and constrain plausible scenarios.
Many realistic problems remain to be solved. Integrated effort from observational and theoretical side is needed!
3. Summary of Part II