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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 • Introduction to galactic outflows and [OII]Blobs • Describing our target: [OII]Blob 10 • Observations • Results • Discussions Galactic Outflow is Important ! • Galactic outflows powered by starformation activities and/or AGNs have been reported. Galactic Outflow is Important ! • Galactic outflows powered by starformation activities and/or AGNs have been reported. NOAO Galactic Outflow is Important ! • Galactic outflows powered by starformation 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 Galactic Outflow is Important ! • Galactic outflows powered by starformation activities or AGNs have been reported. + SN and AGN • Galactic outflows play a significant role in feedback galaxy formation and evolution. – Chemical enrichment of IGM – Regulating star formation Courtesy: Darren Croton Outflow Regulates Star Formation ! [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. [OII]Blob1 Having an AGN Blueshifted FeII2587 absorption Outflow velocity is ~500 km/s [OII] emission Stellar componet FeII absorption ~500 km/s Yuma+13 [OII]Blob4 Blueshifted MgII doublet absorption Outflow velocity is ~200 km/s [OII] emission Stellar componet Yuma+13 [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. Our Target: [OII]Blob 10 • One of the highest SSFR. • No signature of AGN in the available data. [OII] emission Stellar componet Harikane+14 • The aims of our study is … – To check whether an outflow is occuring. – To check the presence of an AGN 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 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 Harikane+14 components. 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 80 km/s 260 km/s 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) [OII]Blob 10 Has an Outflow! • Blueshifted absorption lines indicate gas outflow. • The outflow velocity is 80-260 km/s. Comparable ! • 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 starformation activity could be suppressed. Does [OII]Blob 10 Have an AGN? Does [OII]Blob 10 Have an AGN? It is likely that [OII]Blob 10 is a composite of an AGN and star-forming regions. 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. 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.