First stars and Near Infrared Extragalactic Background Light Sapporo, March 1, 2005 T. Matsumoto...
-
Upload
allison-butler -
Category
Documents
-
view
221 -
download
5
Transcript of First stars and Near Infrared Extragalactic Background Light Sapporo, March 1, 2005 T. Matsumoto...
First stars and
Near Infrared Extragalactic Background Light
Sapporo, March 1, 2005
T. Matsumoto (ISAS/JAXA)
1. Impact of WMAP 2. First stars (pop.III) ?3. Near Infrared Extragalactic Light(NIR EBL)4. Future observations
Recent topics on Cosmology WMAP(Wilkinson Microwave Anisotropy Probe)
Launched on June, 2001Orbit S-E L2
Frequency 23,33,41,61,94 GHzPolarization can be observedAngular resolution 0.2 degree
( cf. COBE:7 degree )
First data was opened on Feb.2003
Fluctuation of CMB observed by WMAP
Consistent with COBEFiner structure is detected
Power spectrum of CMB fluctuation
Positions, heights of peaks providecosmological parameters
Geometry of the UniverseLife of the UniverseBaryon, dark matter, dark energyHubble constant
Douspis et al.
~0.17 +/- 0.04z_rei ~ 20 +/- 8
-----------
Summary of WMAP resultssuggesting inflation universe
● Flat universe Ω=1.04 ± 0.04
● Life of the Universe 134±3 108 yr
● Baryon density Ωm=0.046 ± 0..02
● Dark matter density Ωdm=0.23 ± 0.04
● Hubble constant h=0.72 ± 0.05
● Dark energy ΩΛ=0.71 ± 0.07
● Optical depth for CMB τ=0.17 ± 0.04 Constraint on the re-ionization epoch: z 〜 17
Gunn-Peterson troughs -> Absorption by neutral Hydrogen
Reionization of the Universe
)/(10GP
5~ HHI nn
From Gunn-Peterson troughs in Sloan quasars: 1. Small neutral fractions at z ~ 6 (1% neutral) 2. Sharp transition at z~6 (end of reionization?)
Fan et al. 2001
Reionization epoch is earlier than previously thought
What caused reionization?
Super novae
AGNmini black holes
First stars (Pop.III stars) Integrated light of first stars can be observed
as near infrared background!
First stars (pop.III stars)?
After the recombination era, universe was neutralizedNo metal, H and He onlyCooling through hydrogen molecules
⇨ massive star formation
Luminosity (Eddington limit):4G mc2 M/T ~1.3x1038 M/M○ erg/sec
Temperature T~104.8-5 K
Life timetL~Mc2/L~3x106 yr (~0.007)
Final stage of the evolution M< 40M○ type II super nova 40M○<M< 130M○ black hole 130M○ <M<260M○ pair instability super nova M>260M○ black hole
Can we detect the signature of first stars directly?
A 300 M○
first star at z~15,K-band mag 33(unlikey to be detectable)
First proto-galaxiescan contain as many as 105 stars.(Still not detectable)
(Scherrer 2002; Bromm et al. 2002; Santos et al. 2001)
Interesting wavelength range is 1 to 3 microns!!
Infrared Extragalactic Background Light (IREBL) Cosmic Infrared Background (CIB)
integrated light of distant galaxies and stars
UV and optical radiation can be observed at nearInfrared wavelengths due to redshift
A key observation to delineate the dark age of the Universe
Complementary to galaxy deep survey
Space observation is inevitable!Several rocket flightsCOBE/DIRBEIRTS/NIRS
COBE(COsmic Background Explorer)
• FIRAS
• DMR
• DIRBE(Diffuse Infrared Background Experiment) Absolute photometry of the sky brightness at 1.25, 2.2, 3.5, 4.9, 12, 25, 60, 100, 140, 240 m beam size ~0.7 degree
COBE was launched on 1989 and attained all sky survey.
As for the CIB,COBR team reported detections at far infrared bands
upper limits for other bands
Several authors obtained significant detections at J, K, L bands using COBE data
IRTS(Infrared Telescope in Space)
NIRS(Near Infrared Spectrometer)One of 4 focal plane instruments of IRTS
wavelength coverage 1.4-4.0 m spectral resolution 0.13 mbeam size 8 arcmin. x 8 arcmin.
Compared with COBE/DIRBEsmaller beam capability of the spectroscopysmaller spatial coverage ~7% of the sky
One of mission instruments of small space platform, SFU
launched on March 15, 1995
15cm cold telescope Optimized for diffuse Extended sources Mission life ~ 1 month
Near Infrared Sky
Foreground emission sources
• zodiacal light scattered sunlight by interplanetary dust (IPD)
• zodiacal emission thermal emission from IPD >3.5m
• Milky Way, integrated star light・ It is important to resolve and remove as faint stars as possible.・ Smaller beam is better to avoid confusion
IRTS/NIRS: 8 arcminCOBE/DIRBE: 0.7 degree
Subtraction of foreground emissionIs a critical issue to detect EBL
IRTS observations
7% of the sky was surveyed during IRTS observation period (4 weeks)The data for 5 days before liq. He ran out were used to avoid contaminationThe data at high galactic latitudes are sampled 40<b<58 degree, 10<<70 degree
spectra of 1010 blank skies where no stars are detectedeffective beam size is 8’x20’ due to scanning effect
QuickTime˛ Ç∆TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB
Integrated light of faint stars
Constructed logN/logS model based on the NIRS observation (M.Cohen)
Obtained magnitudes of stars that correspond to the noises→ cut off magnitudes for all wavelength bands cf. 10.4 mag. at 2.24 m
Calculated integrated light of stars fainter than cut off magnitudesfor b=42, b=45, b=48 and applied cosec(b) law
The result is consistent with 2MASSFor the H and K bands
10
15
20
25
30
35
40
45
50
1.3 1.35 1.4 1.45 1.5 1.55
cosec(b)
2MASS(H) and model(1.63 )m
2 (MASS K) (and model2.14 )m
Zodiacal light and emission
Apply physical model by Kelsall et al. (ApJ, 508, 44 1998) to NIRS bands.
Model is based on the annual variationof the zodiacal light observed by DIRBE/COBE.
Calculate the brightness of zodiacal light/emission for all NIRS bands andobserved points.
After subtracting the star light and zodiacal light/emission
Significant isotropic emission was detected for all bands !
-100
0
100
200
300
400
500
600
700
10 20 30 40 50 60 70 80
Ch22,1,63m
, ( )ecliptic latitude degree
_ - _observed sky star light
zodiacal light
residual emission
Residual emission shows no dependence on the galactic plane
Breakdown to emission components
10-8
10-7
10-6
2 3 4
Wavelength ( )m
Observed sky brightness at high ecliptic latitude
Zodiacal light/emission
Isotropic emission ~20 % of dark sky
Integrated light of faint stars
COBE/DIRBE and star countsComparison with other observation
J-band K-band L-band
Dwek & Arendt (1998) 9.9 ±2.9
Gorjian et al. (2000) 22.4±6 11.0 ±3.3 30.7±6 15.4 ±3.3
Wright and Reese (2000) 23.1±5.9 16.8 ± 3.2 31.4±5.9
Wright (2001) 28.9 ±16.3 20.2±6.3 61.9 ±16.3 28.5 ±6.3
Cambresy 54 ±16 27 ±6.7
IRTS/NIRS 27±5 ( 2.24 m)
In unit of nW.m-2.sr-1 Red numbers are based on "very strong no-zodi principle" (VSNZP)All observations are consistent if same zodi model is used!
Spectrum of the observed isotropic emission
Stellar like spectrum was found.
Main error is uncertainty of the zodiacal light model
Consistent with COBE/DIRBE
Significantly brighter than theintegrated light of galaxies !
Spectral gap around 1m
In-band energy flux is ~ 35 nW.m-2.sr-1
10
100
0.2 0.4 0.6 0.8 1 3 5
IRTS/NIRS
Model by Totani et al. 2001
Totani et al. 2001
Bernstein et al. 2002
COBE/DIRBE
Wright and Reese 2000, Kelsall model Fazio et al. 2004
Madau and Pozettti 2000
Cambrecy 2001
Wavelength ( )m
Spectrum of excess emission over ILG can be explained well
by integrated light of first stars!Sarvaterra and Ferrara (MN 339, 973 (2003) zend~8.8, redshifted Ly J band f★=10 〜 50 % massive star formation -> produced metals were confined in black holesz=17 2.2x108 yrz=8.8 5.5x108 yr
10
100
0.5 0.6 0.7 0.8 0.9 1 2 3 4
Model by Salvaterra and Ferrara
NIRS/IRTS Cambresy et al. 2001
Wright and Reese 2000
Bernstein et al. 2002
Wavelength ( )m
Another evidence of NIR EBL
Inverse process of pair anihiration
~TeV) + ~eV -> e+ + e-
when E>(mc2)1/2
Cross section is maximized when the soft phton energy is
e~2(mc2)2/E=0.5(1 TeV/E) eV ~2m
Absorption of TeV- blazer!
BL Lac object H1426+428z=0.129 ■ CAT(1998-2000) ▲ Whipple(2001) ● HEGRA(2002) ○ HEGRA(2002)
lines:model byMapelli and Ferrara
QuickTime˛ Ç∆TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ
ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB
Fluctuation of the sky -1rms fluctuation
Stellar fluctuation is estimated by using the model, but consistent with 2MASS
Fluctuation of zodiacal emission at 12m is less than 1% (IRAS, COBE, ISO)!⇨ Zodiacal light can not explain observed sky fluctuation!
1
10
2 3 4
2MASS stars
b>47, observed_fluc
Read out noisephoton noise
SL_nominal
Wavelength ( )m
Fluctuation of the sky -2Correlation between wavelength bands
-4 10-8
-3 10-8
-2 10-8
-1 10-8
0
1 10-8
2 10-8
3 10-8
4 10-8
-6 10-8 -4 10-8 -2 10-8 0 2 10-8 4 10-8 6 10-8
y = 4.5368e-12 + 0.51344x R= 0.74258
Surface brightness at 2.24
( .m W m
-2.sr
-1)
1.83 Surface brightness at ( .m W m-2 .sr
-1 )
Clear correlation between wavelength bands was detected.Spectrum (color) of fluctuation component is similar to that of isotropic emission
⇨ Isotropic emission is spatially fluctuating
Spectrum of fluctuation
⇨ Excess emission is fluctuating keeping the similar spectrum!
Observed rms fluctuation: ~5% of the sky brightness, ~6% of the zodiacal light, ~20% of the isotropic emission
Nearest pop.III stars (z~8.8) are responsible for the fluctuation!1
10
1
10
2 3 4
Wavelength (
Excess skyfluctuation
Excess emission over ILG
color of flutuatingcomponent
DIRBE/COBE
What causes NIREBL fluctuation?
1. Stellar fluctuation? Model is fairly consistent with 2MASS data!
2. Zodiacal light and/or emission?IRAS, COBE, ISO
3. Faint galaxies?
4. Pop.III stars?
Zodiacal emission is very isotropic!
10-7
10-6
10-5
1 10
Wavelength ( )m
NIRS
MIRS
280Kblackbody
solar spectrum
Spectrum of the zodiacal light and emission (<10 )degree
IRAS: 0.5 degree beam at 15 and 25 mCOBE: 0.7 degree beam at 12, 25 and 60 m
Residual from smooth distribution is less than 1% of peak brightness!
ISO: 3’x3’ pixel, 45’x45’ frame5 fields at different were observed at 25 m
rms fluctuation in one field is ± 0.2% !
Observed fluctuation is 6% of ZLIt is unlikely there exists big difference between scattering and emission
Observations (DIRBE, IRTS/NIRS and NITE) and theory (Cooray et al. 2004)
z-dependence of the model brightness(Salvaterra and Ferrara 2004)
1
10
100
2 3 4
model brightness9<z<1010<z<1111<z<1212<z<1313<z<14
Wavelength ( )m
Can pop.III explain observedFluctuation?
2-point correlation function
Correlation amplitude,
, Angular distanceθ [ ]degree
-20-100102030 IRTS / NIRS
-20-100102030 2MASS
-20-100102030
0 2 4 6 8 10
Random simulation
40
45
50
55
60
60 80 100 120 140 160 180 200
l (galactic longitude, degre)
Å™
Observed sky
Analysis is made for wide band brightness (integrated brightness for 1.43-2.14m)Read out noise is negligibleFluctuation is celestial origin
Data points lie along the belt↓
One dimensional analysis
Power spectrum
1
10
100
0.1 1
IRTS / NIRS2MASSRandom simulation1 upper limit
Angular frequency, q [1/deg]
Specific feature at 1 〜 2 deg.
This scale is,
20 Mpc at z=8.8200 Mps at present
First peak of CMB (l~220, 0.8 deg) corresponds to1.45 deg. at z~8.8
Power spectrum
for subsections
1
10
0.1 1
A (l < 134)
B (l > 134)
Spatial frequency, q [1/deg]
Expected fluctuation and detection capability of IRC/ASTRO-F(Cooray et al. 2004, Ap.J, 606, 611)
⌒Theory:Based on the fluctuation of dark matter.
Observation:Much larger fluctuationSharp peak at 2 deg.
Radiation of pop.III stars do not follow dark matter?
Underlying fluctuation may exists.
Future observations:Subtraction of foreground galaxies is essentail.ASTRO-F is powerful
Theoretical estimation of fluctuation
Kashlinsky et al. 2004
Future observationsIssues to be observed
• Spectral shape Confirmation of the spectral gap at ~1m real? Other spectral features?
• Fluctuation Spatial correlation over the wide range of angular scale Confirmation of 2 degree feature in 2 dimensional imageObserve underlying large scale structure
• Absolute measurements Observation free from ambiguity of the model ZL
ASTRO-F: image at K and L
CIBER (Rocket experiment): spectral observation, image at I and H
Out of zodiacal cloud mission: zodi free observation
10
100
0.2 0.4 0.6 0.8 1 3 5
Wavelength ( )m
1
10
2 3 4
2MASS starsb>47, observed_flucRead out noisePhoton noiseStar light, model
Wavelength ( )m
1
10
100
0.1 1
IRTS / NIRS2MASSRandom simulation1 upper limit
Angular frequency, q [1/deg]
ASTRO-F Formation and evolution of galaxies, stars, and
planets
First dedicated infrared mission of ISAS 70cm cooled infrared telescope Advanced Infrared Survey 50 times higher sensitivity, 10 times better spatial resolution, has longer wavelength band,
than IRAS Instruments IRC(Infrared Camera)
512x412 InSb array camera, 1.5”/pixel band imaging: K, L, and M bands low resolution spectroscopy: R-30 slit 2x50 pixel, R-15 4x50 pixel256x256 SiAs array
FIS(Far Infrared Surveyor)Launch target : January, 2006Orbit : sun synchronous orbit, 750km altitudeMission life: ~1.5 year (liq. He holding time) + 2 years (dedicated to NIR Observations)
Observation of NIREBL with ASTRO-F
Advantages of IRC/ASTRO-F observation
• Point-source rejection by high-resolution imaging observation Limiting magnitude at the K band is ~20 mag. for one pointing observation (~10 min.) This corresponds to ~30 nW m-2 sr-1 for 1 pixel (5) Almost all galactic stars and faint galaxies can be identified
• Discrimination of the fluctuation of the zodiacal light Observation of the same field at the different time epoch
• Spitzer does not have K band
Observation plans
1. Detection of the NIREBLfluctuation over the wide range of angular scale Wide area survey towards north ecliptic pole (NEP) is being proposed. Coordination with galaxy deep survey group
2. Detailed study of the spectrum of IREBL Low resolution spectroscopy at different ecliptic latitudes (2~5m) Spectrum without contamination of stars and galaxies can be obtained
“NEP-Deep & Wide” : SummaryNEP-Deep Field, 50 pointing/FOV 0.5 deg2
2.8 deg
NEP-Wide Field, 4 pointing/ FOV
Area: 2.8 deg2
N2 N3 or N4
2 2
S7 S11
2 2
L15 L24
2 2
Revised on 28th Oct. 2004
ASTRO-F detection limit
Wide(1pixel) 5
Deep(1pixel) 5
Wide(100pixels) 5
• IRC imaging observations at NEP are enough sensitive to detect the CNIRB fluctuation seen by IRTS• Spectroscopic measurement of the CNIRB mean level avoiding the contamination by normal galaxies
Spectroscopy (100pixels x 10sky) 5
K >20mag Integrated flux of galaxies
Expected fluctuation and detection capability of IRC/ASTRO-F
(Cooray et al., submitted to Ap.J.)
CIBER: Cosmic Background Explorer
ObjectivesSounding rocket observations at the wavelengths below the K band!NASA’s Black Brandt rocket
1. Spectrometer: Confirmation of spectral gap at ~1m low resolution spectroscopy, 0.8m<<2.0m
2. Imager: Observation of sky fluctuations at the I and H bands 2-dimension analysis
10
100
0.2 0.4 0.6 0.8 1 3 5
Wavelength ( )m
1
10
100
0.1 1
IRTS / NIRS2MASSRandom simulation1 upper limit
Angular frequency, q [1/deg]
Instrumentation of CIBER
Spectrometer7.3 cm dia. Telescope1 arcmin./pixel, 4 degree frame low resolution spectroscopy
0.8-2.0m, R~10
Imager15 cm dia. Telescope x210 arcsec/pixel, 2.8 degree frame I and H
Optical design of the spectrometer
Optics 13 lenses & 1 prism
linear dispersion
multiple slits (4 apertures)
Aperture 73.3 mmφ-F number /2F
FOV 4 4x degrees
Pixel FOV 1 1x arcmin
Slit size 1 256x arcmin
Wavelength = 0.85~2.00 m
Spectral resolution /Δ = 21~23 Optical efficiency 0.8
Focal plane array 256 256 x HgCdTe
Operating temperature 77 K
Quantum efficiency 0.5 Dark current < 0.1 -/e s
( )Readout noise CDS 10 -e
( )Photo current dark sky 10~20 -/e s
(Photon noise=15 )s 12~17 -e
(15 , 3Limiting mag s) = 15.0J
Imager Optics
Aperture 15 cm
Pixel size 10 arcsec
FOV 2.8 x 2.8 degrees
0 .95 ( )I 1 .6 ( )H m
Δ/ 0 .5 0 .5
Optical
efficiency
0 .3 0 .5
Photo
current
23 32 -/e s
Dark current < 0 .03 < 0 .03 -/e s
RN (CD )S < 10 < 10 -e
νIν (sky) 800 390 nW m-2 sr-1
δνIν in .st 18/p ix (1 ) 7/p ix (1 ) nW m-2 sr-1
δνIν conf. 8/p ix (1 ) 5/p ix (1) nW m-2 sr-1
δνIν total 20/p ix (1 ) 9/p ix (1 ) nW m-2 sr-1
galaxy cut 1 3e
0 .8 %
6 3e
5 %
# / sq degree
pixe l loss
δFν total 140 (5)
18 .0 (5)
120 (5)
17 .5 (5)
J y
Mag
Detection limit of the spectrometer
1
10
100
0.5 0.6 0.7 0.8 0.9 1 2 3 4
Wavelength [ ]m
1 , 15 , 1pixel s
HST
IREB brightness
ZL
ZE
1σ fluctuation
4 x 4 pixels, 50s, 1σ
400 pixels, 15s, 1σ
Simulated spectrum of the sky
0 100
2 102
4 102
6 102
8 102
1 103
1.2 103
1.4 103
0.8 1 1.2 1.4 1.6 1.8 2
EBL fit
ZL(10)+EBL
ZL(90)+EBL
IRTS
HST
Wavelength [um]
=10
=90
Expected performance of the imager
Spatial power spectrum of Pop III fluctuations (red curves), local galaxy fluctuations (correlations term light blue curves, shot term dashed curves) for 3 different cutoff magnitudes, and the total signal (solid blue curves). The 18.5 mag cutoff is for the rejection level from the NAME images alone; the faintest cutoff (I = 25.5 and H = 21) comes from ground-based measurements overlapping our images. The data points show the errors from NAME in a 100 s observation, including both instrument noise and sample variance. We assume there are no Pop III fluctuations detectable at I-band, following the IRB star spectrum in Fig. 3. NAME can easily detect the optimistic Pop III signal (this model produces a cumulative background of 25 nW m-2 sr-1, consistent with the missing amount in Figs. 1 and 3), clearly distinguished by its different power spectrum from local galaxies at H-band. NAME has sufficient sensitivity to detect the pessimistic Pop III signal (this model produces a background of 3 nW m -2 sr-1), although it is obscured by local galaxy fluctuations at a limiting magnitude of H = 21. Reducing the cut-off magnitude further is possible, and would allow us to positively extract even the signal of the pessimistic model.
Configuration of the telescope system
QuickTime˛ Ç∆TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ
ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅBQuickTime˛ Ç∆
TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB
Payload configuration
Observation plan
Fig. 17. Proposed sequence of observations superposed on the trajectory of the NITE payload. Separation from the rocket engine occurs at 85 s, followed by despin, opening of the vacuum shutter door at 95 s, and slewing the payload to the first science target. The instrument observes 5 science fields before closing the shutter door, reentry into the atmosphere, and recovery operations
Organization and scheduleOrganization
Japan: ISAS(Matsumoto, Matsuura, Wada, Matsuhara) Nagoya U. (Kawada, Watabe)
US: Caltech/JPL(J.Bock)UCSD (B.Keating)
Korea: KAO (S. Pak, D-H. Lee)
ScheduleJune, 2004 Proposal to NASA
Now approved!No-funded launch!
Spring, 2007 First launch at White SandsSpring, 2008 Second launch
Funding?
The life of an IR rocket (Jamie’s previous experiment)
Solar sail mission
Out of zodiacal cloud mission
● Free from ZL and IPD emission
● Accurate absolute measurement of E
BL
without IPD model ambiguity is possi
ble
● Observation of the mid-infrared
background is possible
Free from zodiacal light/emission
provides decisive result for the NIREBL!
Possible mission concept of out of zodiacal cloud mission!
Scientific objectives Accurate measurement of spectrum and fluctuation of IREBL
InstrumentationTelescope 5cm dia. lens systemWavelength range 0.8-2.2mPixel FOV ~10’Detector HgCdTeCooling system radiation coolingWeight 3 kg
Summary
1. CMB polarization observed by WMAP indicates that the Universe was reionized at z~17 by the first massive stars (pop.III stars).
2. Independent observations by COBE and IRTS provide detections of significant near infrared extragalactic background light. Recent observations of Tev- Blazers support its cosmological origin.
3. The near infrared extragalactic background observed by IRTS and COBE could be consistent with pop.III star scenario.
4. Spectrum observed by IRTS suggests the redshift at the end of pop.III era is ~9.
5. Fluctuation of the sky was detected (~20% of EBL) by IRTS and COBE which is too large to be explained with the standard model.
6. Near infrared background is a unique tool to investigate the pop.III stars. ASTRO-F, CIBER(Rocket experiment) and Solar-Sail missions will provide valuable information on the pop.III era.
NIREBL is a unique tool to investigate the first stars!
QuickTime˛ Ç∆TIFFÅià≥èkǻǵÅj êLí£ÉvÉçÉOÉâÉÄ
ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB
CMB
z=1,000 3x105 year
?Near infrared background
z~10 5x108 year
Cosmic Microwave Background(CMB)
Most distant observable object
The Universe ~4x105 years after big bangFossil photons
COBE(COsmic Background Explorer) CMB Map(launched on 1989 by NASA)
CMB is very uniform
But
Fluctuation of ~10-5 is detected ⇨
Present Universe Extremely non uniform!Large scale structure, Cluster of galaxies, galaxies, starsplanets, -------
Evolution from uniform and isotropic Universe to extremely non uniform Universe?How first stars and galaxies formed?
Evolution of the Universe
Dark age of the Universe
Prepared by N. Fujishiro
Proposed Survey Field
IRC background measurements around NEP
Spectral resolution
/
Survey area [sq.degree]
Exposure time per frame
[# of pointings]
Single pixel detection limit (5) *
[nW/m2/sr]
Number of galaxies per camera frame**
Number of dark pixels per frame ***
Ultra-Wide
(Phase-3)
3 100 TBD ~ 10
(pixel binning)
- -
Wide 3 2.8 2 (500 s) 10 - -
Deep 3 0.5 25 (1.4 hrs) 3 3000 >10^5
Ultra-Deep 3 - - - - -
* in unit of surface brightness (I
** FOV of the IRC camera frame is 10’x10’*** number of pixels available for the background analysis = total number of pixels – (confusion factor) x (number of galaxies)
= 1.7x10^5 – (3pics x 3pics) x (number of galaxies)
Spectral resolution /
Survey area Exposure time Detection limit (5)
[nW/m2/sr]
Number of galaxies
Number of dark pixels
Spectroscopy 30
( 2 – 5 m)
3” x 73”
x 100 directions
(various b and )
1 pointing (500 s)
x 100 directions
30 (pixel binning)
~10 (10 sky average)
2 90
1. Wide-band deep imaging in K, L and / or M bands
2. Spectroscopy
0.9
1
1.1
1.2
1.3
1.4
1 1.5 2 2.5 3 3.5 4 4.5
Wavelength (
Lensed galaxy at z~10?
Pello et al. 2004, A&A 416, L35-L40.
SED and spectrum
IRC SURVEY STRATEGIESIRC SURVEY STRATEGIES
0.02 1 10100
1000 ?
Area (sq. deg.)
Num
ber o
f Poi
ntin
gs
100
10
1
Depth and Area
Theory to Reality: Near-IR wide-field surveys
5-sigmapoint sourcedetection(planned)
(experiments at this end are preferred)
IRC background measurements around NEP
1. Wide-band deep imaging in K, L and M bands
* in unit of surface brightness (I
** FOV of the IRC camera frame is 10’x10’*** number of pixels available for the background analysis = total number of pixels – (confusion factor) x (number of galaxies)
= 1.7x10^5 – (3pics x 3pics) x (number of galaxies)
Spectral resolution /
Survey area Exposure time Detection limit (5)
[nW/cm2/sr]
Number of galaxies
Number of dark pixels
Spectroscopy 30
( 2.0 – 5 m)
3” x 73”
x 100 directions
(various b and )
1 pointing (500 s)
x 100 directions
30 (pixel binning)
~10 (10 sky average)
2 90
2. Spectroscopy
Spectral resolution
/
Survey area [sq.degree]
Exposure time per frame
[# of pointings]
Single pixel detection limit (5) *
[nW/cm2/sr]
Number of galaxies per camera frame**
Number of dark pixels per frame ***
Wide-field Shallow( phase-3)
3 100 1 (500 s) 30 2x10^3 >1.5x10^5
Shallow (Phase-1,2) 3 10 1 (500 s) 30 2x10^3 >1.5x10^5
Deep (Phase1,-2) 3 1 10 (1.4 hrs) 10 (3-4)x10^3 >1.3x10^5
Ultra Deep
(Phase-1, 2)
3 0.02 100 (14 hrs) 3 (0.5-1)x10^4 >8x10^4
Fluctuation of the sky-4Detection of fluctuation with 2MASS dataKashlinsky et al. ApJ 279, L53 (2002), Odenwald et al. ApJ 283, 535 (2003)
Interpretation of the 2MASS fluctuation with pop.III stars
Theoretical estimation of fluctuation I.Magliocchetti, Salvaterra and Ferrara MN, 342, L25 (20
03)
Sharp drop at ~200 arcsec 8.6 Mpc at zend=8.8
Fluctuation is dominant at the J band