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Some Preliminary Results from AKARI’s NEP Survey and Clusters of Galaxies Program. Hyung Mok Lee (Seoul National University) with Myungshin Im. Hyunjin Shim. Seong Jin Kim, Myung Gyoon Lee, Narae Hwang, H. Matsuhara, K. Wada, S. Oyabu & AKARI NEP and Cluster of Galaxies Survey Team. - PowerPoint PPT Presentation
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Some Preliminary Results from AKARI’s NEP Survey and Clusters of Galaxies Pro-gram
Hyung Mok Lee(Seoul National University)
with Myungshin Im. Hyunjin Shim. Seong Jin Kim, Myung Gy-oon Lee, Narae Hwang, H. Matsuhara, K. Wada, S. Oyabu & AKARI NEP and Cluster of Galaxies Survey Team
February 19, 2008 1SDSS-KSG 동계워크샵
The AKARI (ASTRO-F) Project
IR Space Mission by Japan Aerospace Exploration In-stitutes (JAXA)/Institute for Space and Aeronautical Science (ISAS) with ESA support
Collaborative Institutes in Japan: - University of Tokyo - Nagoya University - Communications Research lab. - National Astronomical Observatory (NAOJ) International Collaboration - Seoul National University (Pre- and post-flight simula-
tions/data reduction) - European Consortium (Imperial, Open Univ., Sussex,
Groningen: data reduction)
February 19, 2008 2SDSS-KSG 동계워크샵
Telescope
Mirror 68 cm, F/6 SiC
• Cryogenic System– 170 liter LHe + Stirling Cooler– T(tel) = 5.8 K,
T(detector) = 1.8 K (st. Ge:Ga), 15 K (InSb)February 19, 2008 3SDSS-KSG 동계워크샵
Focal Plane Instruments
IRC: Near- and Mid-IR Camera
FIS: Far-IR Surveyor
February 19, 2008 4SDSS-KSG 동계워크샵
February 19, 2008 SDSS-KSG 동계워크샵
Orbit and Observing Modes
Sun Syncrhonous Orbit with a=7081.093 km e=0.002102013
Altitude ~ 750 km Orbital Period
~100 minutes Max Pointings
3 / revol. Pointing Obs. < 10 min per pointing
5
Features Main purpose: all sky survey in mid to far infrared +
pointing observations Higher resolution compared to IRAS (e.g., 0.5-0.8’
compared to 6’ at far IR) Wide field of view (10’ x 10’ for IRC) Wide and continuous wavelength coverage from near
to far IR (2-170 microns) for both wide-band imaging and spectroscopy
Scientific programs include all sky survey, large area surveys (NEP, SEP), Mission Programs, and open time programs
February 19, 2008 6SDSS-KSG 동계워크샵
AKARI Sensitivity (pre-flight esti-mates) Spitzer cannot
cover this range
February 19, 2008 7SDSS-KSG 동계워크샵
Timeline of AKARI Launched on February 21, 2006, 9:28
am (UT) Due to some problems in AOCS,
aperture lid jettison was delayed by about a month (April 13, 2006)
Started all sky survey on May 8, 2006 (Phase 1)
Phase 2 observation started in No-vember, 2006
Helium boiled out on August 26, 2007 (550 days after launch)
Phase-3 observation will begin early April, 2004 with NIR channel only
February 19, 2008 8SDSS-KSG 동계워크샵
AKARI NEP Survey One of the Large Area Surveys of AKARI because of high
visibility Consists of Deep (0.38 sq. deg) + Wide area (5.8 sq. deg.)
surveys (Matsuhara et al. 2006) Other wavelength data: - Optical surveys that include the NEP Deep area are done with
CFHT (Hwang et al. 2007) and Subaru telescope - Optical survey for the entire NEP Wide survey area has been
carried out using 1.5 m Telescope at Maidanak Observatory by SNU team
- Radio survey with WSRT at 20 cm has been carried out by Open Univ. team .
February 19, 2008 9SDSS-KSG 동계워크샵
North Ecliptic Pole (NEP) Survey
A wide area, multi-wavelength blank field sur-vey
February 19, 2008 10SDSS-KSG 동계워크샵
NEP Survey AreaGreen: WidePink: DeepYellow: CFHT Optical Sur-vey
February 19, 2008 11SDSS-KSG 동계워크샵
NEP publications (PASJ special issue, October 2007) Nature of Infrared Sources in 11 mm Selected Sample from
Early Data of the AKARI North Ecliptic Pole Deep Survey (Lee et al. )
Optical Identification of 15mm Sources in the AKARI Per-formance Verification Field toward the North Ecliptic Pole (Matsuhara et al.)
Multi-Wavelength Analysis of 18mm-Selected Galaxies in the AKARI/Infrared-Camera monitor field towards the North Ecliptic Pole (Takagi et al.)
February 19, 2008 12SDSS-KSG 동계워크샵
Nature of 11 mm Selected Sample Partial data of NEP-
Deep survey carried out during the PV phase (May 2006)
The field lies within CFHT NEP-W field, where g’, r’, i’, z’-band data are available.
N2, N3, N4, S7, S9, S11 bands, 3 exposures each
Total exposure time: 10 – 20 minutes per filter
February 19, 2008 13SDSS-KSG 동계워크샵
S11 Flux Limited Sample Why 11 mm sample? - 6.3 & 7.7 mm PAH feature can be
redshifted to S11 band for z=0.2-0.7 objects
5-s detection =19.5 m(AB), or 60 mJy
Total number of detected sources ~ 180
Complete test: >90% at 18.5 mag. (72 sources)
Source distribution n(m) ~ m0.6
February 19, 2008 14SDSS-KSG 동계워크샵
Classification of sources Optical morphology + optical-IR SED- Stars (13 [18%])- Star forming disk galaxies (51 [70%])- Early type galaxies (4 [6%])- AGNs (4 [6%])
February 19, 2008 15SDSS-KSG 동계워크샵
8
7
175607+661245
175609+661509
Optical-IR Atlases
z=0.64 X-ray source
15 175708+661431 star
AGN?CFHT N2 N3 N4 S5 S9W S11
February 19, 2008 16SDSS-KSG 동계워크샵
4
5
3
175648+661159
175648+661242
175651+661307
Disk galaxy
Disk galaxy
Disk galaxy
February 19, 2008 17SDSS-KSG 동계워크샵
Optical to Mid-IR SEDs: Disk galaxies
Broad peak in near IR (redshifted 1.6 micron bump) + brightening at mid-IR
Majority of (~70 % ) the S(<18.5) sample
February 19, 2008 18SDSS-KSG 동계워크샵
SEDs of AGN 4 out of 72 (6%) sources
are classified as AGNs Two X-ray sources with
measured redshifts (z=0.64, 1.43)
Well fitted by power-law SED
February 19, 2008 19SDSS-KSG 동계워크샵
SEDs of stars
Well fitted by black-bodies13 sources (18%)
February 19, 2008 20SDSS-KSG 동계워크샵
SED fitting to disk galaxies: redshift and LIR
SED templates by Chary & Elbaz (2001)
PAH features allow us to determine the redshift
0.2<z<0.7, LIR ~ 1010 – 1012 Lsun
February 19, 2008 21SDSS-KSG 동계워크샵
Other interesting sources with S11>18.5
Teff ~ 2500 K BB with IR excess?
A candidate for brown dwarf
February 19, 2008 22SDSS-KSG 동계워크샵
A Very Red Object
• No optical detection but seen at all IRC bands
1. Power-law with n-2.8 (dust obscured AGN)
2. Dust extinct star forming galaxy at z>5
3. A few hundred Myr object at z~9.5 (too massive)?
February 19, 2008 23SDSS-KSG 동계워크샵
A flat spectrum Object
• Very flat spectrum (not an AGN)• A galaxy at z~3.5?
February 19, 2008 24SDSS-KSG 동계워크샵
Summary of 11 micron sources We have looked at the properties of s11 selected sources in
the early data of NEP survey- Mostly star forming disk galaxies at moderate redshifts
(0.2<z<0.7)- Stars- AGNs at various redshifts- A number of interesting objects: brown dwarf, dusty AGN,
flat spectrum- few interesting objects must be looked at more carefully The depth of the current data set is similar to that of NEP-
Wide useful for the study of star forming galaxies in moderate redshifts
February 19, 2008 25SDSS-KSG 동계워크샵
NEP -Wide Data Consists of 446 frames Mosaic images have been pro-
duced for N2, N3, N4, S7, S9, S11, L15, L18 bands
A band-merged image has been produced
Sources are detected in band-merged image
Photometry has been done on single band images catalogue has been produced
February 19, 2008 26SDSS-KSG 동계워크샵
Band merged mage : N2+N3+N4+S7+S9+S11+L15+L18
97060 sourcesare detected
February 19, 2008 27SDSS-KSG 동계워크샵
Some Preliminary Numbers Area coverage: 5.8 sq. deg.
= 20,880 sq. arc. Min > 200 times larger area than the analized area
Total number of sources ~100,000
11 micron sources ~20,000 (<18.5 mag)
* If 70% are spirals, total number of S-galaxies will be ~14,000
February 19, 2008 28SDSS-KSG 동계워크샵
Clusters of Galaxies Mission Pro-gram
February 19, 2008 SDSS-KSG 동계워크샵 29
Purposes:- Study the evolution of galaxies in cluster environments Divided into 3 subprograms depending on z: - Low-z (z<0.3) + how star formation activities are affected by the cluster merging? + 10 clusters of galaxies with different merging stages: quiescent, minor merger, major
merger - Mid-z (0.4<z<1.3) + Sources selected from Subaru/S-cam imaging data + Deep MIR imaging of selected clusters to detect hidden star formation, stellar mass,
etc. - High-z (z>1.3) + Try to find overdensity around the High-z Radio Galaxies. + Deep imaging in NIR and MIR
Outline of the program
February 19, 2008 30SDSS-KSG 동계워크샵
Low-z example:Abell 2065
Data reduction by Hyun Jong SEO
-Redshift : 0.072
February 19, 2008 31SDSS-KSG 동계워크샵
A2065
Model fitting
■ Chary & Elbaz (2001)
■ Piovan et al. (2003)
February 19, 2008 32SDSS-KSG 동계워크샵
A2065
Distribution of E and S galaxies: effects of ram pressure stripping? [very preliminary]
February 19, 2008 33SDSS-KSG 동계워크샵
Summary AKARI’s survey of NEP region provides a wealth of data
for galactic and extragalactic sources 11 micron sample is composed of mostly star forming gal-
axies at z=0.2~0.7 Other wavelength selected samples probe different redshift
ranges (i.e., 15 micron and 18 micron for z~1) Studies of clusters of galaxies should provide important
clues to the environmental effects Complementary observations during warm mission is now
being planned
February 19, 2008 34SDSS-KSG 동계워크샵
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