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: 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 star- formation activities and/or AGNs have been reported.

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

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

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 Outflow Regulates Star Formation ! + SN and AGN feedback Courtesy: Darren Croton

[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 Yuma+13 [OII] emission Stellar componet ~500 km/s FeII absorption

[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. The aims of our study is … –To check whether an outflow is occuring. –To check the presence of an AGN [OII] emission Stellar componet Harikane+14

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

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

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

Estimating Escape Velocity We assume singular isothermal halo truncated at r=r h. (r h /r=10-100) Relation between escape velocity v esc and circular velocity v c Circular velocity is estimated from [OII] line width (Rix+97)

The difference of the velocities MgII absorption → 260±40 km/s FeII absortption → 80±50 km/s There are three possibilities explaing this difference. –Emission filling in MgII absorption –Difference in oscillator strengths –FeII absorption in foreground galaxy

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.

Outflow Rate and Mass Loading Factor Mass outflow rate We estimate N(H) using MgII doublet ratio. → Mass loading factor Relatively higher than mass loading factors of galaxies of Arribas+14 and Rupke+05.

Summary We present the Keck/MOSFIRE and Magellan/LDSS3 spectrosopy for [OII]Blob 10. [OII]Blob 10 has an outflow whose velocity is 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.