Some Preliminary Results from AKARI’s NEP Survey and Clusters of Galaxies Program

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)


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 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


AKARI Sensitivity (pre-flight esti-mates) Spitzer cannot

cover this range


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


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 .


North Ecliptic Pole (NEP) Survey

A wide area, multi-wavelength blank field sur-vey


NEP Survey AreaGreen: WidePink: DeepYellow: CFHT Optical Sur-vey


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.)


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


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


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%])


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


4

5

3

175648+661159

175648+661242

175651+661307

Disk galaxy

Disk galaxy

Disk galaxy


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


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


SEDs of stars

Well fitted by black-bodies13 sources (18%)


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


Other interesting sources with S11>18.5

Teff ~ 2500 K BB with IR excess?

A candidate for brown dwarf


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)?


A flat spectrum Object

• Very flat spectrum (not an AGN)• A galaxy at z~3.5?


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


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


Band merged mage : N2+N3+N4+S7+S9+S11+L15+L18

97060 sourcesare detected


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


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


Low-z example:Abell 2065

Data reduction by Hyun Jong SEO

-Redshift : 0.072


A2065

Model fitting

■ Chary & Elbaz (2001)

■ Piovan et al. (2003)


A2065

Distribution of E and S galaxies: effects of ram pressure stripping? [very preliminary]


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


Documents

Some Preliminary Results from AKARI’s NEP Survey and Clusters of Galaxies Program