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MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18: Gas Outflow and Energy Source

MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18: Gas Outflow and Energy Source. Yuichi Harikane (The University of Tokyo) Masami Ouchi , Suraphong Yuma, Michael Rauch, Kimihiko Nakajima, Yoshiaki Ono arXiv : 1406.7052 Accepted for publication in ApJ. Outline.

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MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18: Gas Outflow and Energy Source

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  1. MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18:Gas Outflow and Energy Source Yuichi Harikane (The University of Tokyo) Masami Ouchi, Suraphong Yuma, Michael Rauch, Kimihiko Nakajima, Yoshiaki Ono arXiv: 1406.7052 Accepted for publication in ApJ

  2. Outline • Introduction to galactic outflows and [OII]Blobs • Describing our target: [OII]Blob 10 • Observations • Results • Discussions

  3. Galactic Outflow is Important ! • Galactic outflows powered by star-formation activities and/or AGNs have been reported.

  4. Galactic Outflow is Important ! • Galactic outflows powered by star-formation activities and/or AGNs have been reported. NOAO

  5. Galactic Outflow is Important ! • Galactic outflows powered by star-formation activities and/or AGNs have been reported. • Galactic outflows play a significant role in galaxy formation and evolution. • Chemical enrichment of IGM • Regulating star formation

  6. Galactic Outflow is Important ! • Galactic outflows powered by star-formation activities or AGNs have been reported. • Galactic outflows play a significant role in galaxy formation and evolution. • Chemical enrichment of IGM • Regulating star formation + SN and AGN feedback Courtesy: Darren Croton Outflow Regulates Star Formation !

  7. [OII]Blobs Have Galactic Outflows • [OII]Blobs are galaxies with strong and spatially extended [OII] emission beyond their stellar components. • Extended metal emission → strong outflow • Yuma+13 find 12 [OII]Blobs at z~1.2 using a Subaru large-area narrowband survey.

  8. [OII]Blob1 Having an AGN Blueshifted FeII2587 absorption Outflow velocity is ~500 km/s Stellar componet [OII] emission FeII absorption ~500 km/s Yuma+13

  9. [OII]Blob4 BlueshiftedMgIIdoublet absorption Outflow velocity is ~200 km/s Stellar componet [OII] emission Yuma+13

  10. [OII]Blobs Have Galactic Outflows • [OII]Blobs are galaxies with strong and spatially extended [OII] emission beyond their stellar component. • Extended metal emission → strong outflow • Yuma+13 find 12 [OII]Blobs at z~1.2. • [OII]Blobs are expected to have outflows.

  11. Our Target: [OII]Blob 10 • One of the highest SSFR. • No signature of AGN in the available data. • The aims of our study is … • To check whether an outflow is occuring. • To check the presence of an AGN Stellar componet [OII] emission Harikane+14

  12. Observations • Keck/MOSFIRE, Y-band (9800-11000Å), 2.4h • Hβ4861, [OIII]4959,5007 • To check the presence of AGN • Magellan/LDSS3, VPH-blue (4800-6600Å), 2.5h • Metal absorption lines. • To check whether [OII]Blob10 has an outflow • Magellan/LDSS3, VPH-red (6700-8600Å), 0.5h • [OII]3726,3729

  13. Results: MOSFIRE • Hβ, [OIII] doublet lines are detected with high significance levels. • Systemic redshift is z=1.1800±0.0002 • These lines appear to have two components. Harikane+14

  14. Results: LDSS3 with VPH-blue • Blueshifted FeII2587 and MgII2796,2804 absorption lines are identified with 2.7 and 5.5 σ levels, respectively. Harikane+14 260 km/s 80 km/s

  15. Results: LDSS3 with VPH-red • [OII]3726,3729 emission lines are detected with high significance level. • The two components of each doublet line are not resolved. R~1710 (cf. R~3390 in MOSFIRE spectrum)

  16. [OII]Blob 10 Has an Outflow! • Blueshifted absorption lines indicate gas outflow. • The outflow velocity is 80-260 km/s. • Escape velocity is 250±140 km/s. • Estimated under the assumption of a singular isothermal halo potential. • Some fraction of outflowing gas would escape from [OII]Blob 10 and the star-formation activity could be suppressed. Comparable !

  17. Does [OII]Blob 10 Have an AGN?

  18. Does [OII]Blob 10 Have an AGN? It is likely that [OII]Blob 10 is a composite of an AGN and star-forming regions.

  19. Implications of Two Components. • Two strong star-forming regions. • A galaxy merger. • A combination of a galaxy and an outflow knot. None of these three possibilities can be conclusively ruled out given current results.

  20. Summary • We present the Keck/MOSFIRE and Magellan/LDSS3 spectrosopy for [OII]Blob 10. • [OII]Blob 10 has an outflow whose velocity is 80-260 km/s. • This outflow velocity is comparable to the escape velocity, implying that the some fraction of outflowing gas would escape. • [OII]Blob 10 is likely to be a composite of an AGN and star-forming regions.

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