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The Environmental Impacts on the Star Formation Main Sequence Tackled by MAHALO-Subaru Campaign Yusei Koyama (NAOJ) Subaru user’s meeting (2014/1/19-21)Subaru.

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Presentation on theme: "The Environmental Impacts on the Star Formation Main Sequence Tackled by MAHALO-Subaru Campaign Yusei Koyama (NAOJ) Subaru user’s meeting (2014/1/19-21)Subaru."— Presentation transcript:

1 The Environmental Impacts on the Star Formation Main Sequence Tackled by MAHALO-Subaru Campaign Yusei Koyama (NAOJ) Subaru user’s meeting (2014/1/19-21)Subaru user’s meeting (2014/1/19-21) T. Kodama (NAOJ), M. Hayashi (ICRR/Tokyo), K. I. Tadaki (NAOJ), I. Tanaka (NAOJ), R. Shimakawa (Sokendai), M. Tanaka (NAOJ), I. Smail (Durham), J. Kurk (MPE), D. Sobral (Leiden/Lisbon), M. Swinbank (Durham), J. Geach (Hertfordshire), P. Best (Edinburgh) MAHALO-Subaru collaboration

2 Star Formation “Main Sequence” Elbaz et al. (2007) = SFR-M ★ relation for star-forming galaxies Main Sequence (normal SF) Starburst Passive log M ★ [M  ] SFR [M  /yr]

3 From NEWFIRM medium-band survey (Whitaker et al. 2012) SF main sequence out to z>2

4 Galaxy properties vs. Environment E S0 Spiral High-density “ Morphology–Density Relation” red, old, low SF activity blue, young, high SF activity Low-density (Dressler 1980)

5 Little environmental impacts ? Local star-forming galaxies from SDSS (Peng et al. 2010) low-density (z=0) log M ★ SF main sequence is “independent” of environment at z=0 high-density (z=0) log SFR [M  /yr]

6 low density Field Cluster high density Little environmental impacts ?

7 Q: How about in distant universe?

8 MAHALO-Subaru project Narrow-band H  /[OII] emission-line survey for 0.4 { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/13/3884772/slides/slide_8.jpg", "name": "MAHALO-Subaru project Narrow-band H  /[OII] emission-line survey for 0.4

9 High-z structures revealed by MAHALO (Koyama+11) (Koyama+10) (Hayashi+10, 11) (Tadaki+12) (Koyama+13) (Hayashi+12) z=0.4 z=0.8 z=1.5 z=1.6 z=2.2 z=2.5 Many strong emitters in z>1.5 cluster cores Many strong emitters in z>1.5 cluster cores

10 HiZELS: High-Z Emission-Line Survey Collaborators: I. Smail, P. Best, D. Sobral, J. Geach, M. Swinbank H  @ z=0.4 H  @ z=0.8 H  @ z=1.5 H  @ z=2.2 Total ~2 deg 2 survey in COSMOS & UDS Sobral et al. (2013) Subaru filter UKIRT filter ~500-2000 H  emitters at each redshift, providing excellent comparison sample for our MAHALO cluster samples.

11 Cluster vs. Field comparison out to z~2 Important Notes: 1)We select galaxies with EWr >30A as SF galaxies. 2)We use galaxies R c < 2 Mpc (physical) as “cluster” galaxies. zT( look-back) Cluster (MAHALO) Field (HiZELS) log M( lim) SFR(lim) 0.4 4 Gyr CL 0939 ( N gal =80) NBz ( N gal =252) 9.00.3 0.8 7Gyr RXJ1716 ( N gal =34) NB J ( N gal =424) 9.84.0 2.2 10 Gyr PKS1138 ( N gal =48) NB K ( N gal =583) 10.015.0 (Koyama et al. 2013b, MNRAS, 434, 423)

12 Cluster vs. Field comparison out to z~2 (Koyama et al. 2013b, MNRAS, 434, 423) H  emitters with EWr > 30A Main sequence is always independent of environment since z~2 !

13 Interpretation: rapid SF quenching Cluste r

14 Interpretation: rapid SF quenching rapid quenching slow quenching M★M★ SFR M★M★ : normal SF galaxy : transitional galaxy : passive galaxy ✗ ✓

15 M ★, SFR, ΔMS distribution : Field : Cluster (MAHALO) (HiZELS) Excess of massive galaxies in proto-cluster PKS1138-262 (Koyama et al. 2013b) M SFR M M

16 Our MOIRCS+NB(H  ) survey revealed red  emitters occupy the core of z=2.16 proto-cluster (PKS1138-262). Massive SF galaxies in z>2 proto-cluster (Koyama et al. 2013a) : 24um-source Red emitters are massive (M ★ >10 11 M  ), and clearly dominate dense environment at z~2. ■ : red HAE (J-K>1.4) ■ : green HAE (0.8 { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/13/3884772/slides/slide_16.jpg", "name": "Our MOIRCS+NB(H  ) survey revealed red  emitters occupy the core of z=2.16 proto-cluster (PKS1138-262).", "description": "Massive SF galaxies in z>2 proto-cluster (Koyama et al. 2013a) : 24um-source Red emitters are massive (M ★ >10 11 M  ), and clearly dominate dense environment at z~2. ■ : red HAE (J-K>1.4) ■ : green HAE (0.8

17 Dust extinction vs. environment (Koyama et al. 2013b) Dust extinction may be higher in high-density environments. z=0.4 sample A(H  ) from SFR(IR)/SFR(H  ) A(H  ) from A(H  )-M ★ relation (Garn & Best 2010) A H  -M ★ relation (z=0)

18 Conclusions (1) With MAHALO-Subaru campaign, we find that SF main sequence is independent of environment at any time in the history of universe since z~2, suggesting rapid SF quenching. (2) SF galaxies in z=2.2 proto-cluster environments tend to be more massive (and showing redder J-K colours) than the field counterparts at the same redshift. (3) SF galaxies “surviving” in high-density environments tend to be more highly obscured by dust, suggesting a different mode of SF activity in clusters/groups.  M ★ distribution “along” the MS does depend on environment.  Environment may affect dust properties (SF geometry or mode).  Cluster vs. field difference is always small (0.2 dex at maximum)


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