A Giant Green Pea Identified in the Spectroscopy of Spatially Extended [OIII] Sources. (arXiv:1904.11510v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Yuma_S/0/1/0/all/0/1">Suraphong Yuma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ouchi_M/0/1/0/all/0/1">Masami Ouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fujimoto_S/0/1/0/all/0/1">Seiji Fujimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kojima_T/0/1/0/all/0/1">Takashi Kojima</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sugahara_Y/0/1/0/all/0/1">Yuma Sugahara</a>

We present the results of the deep Subaru/FOCAS and Keck/MOSFIRE spectroscopy
for four spatially extended [O III]$lambdalambda$4959,5007 sources, dubbed [O
III] blobs, at z=0.6-0.8 that are originally pinpointed by large-area Subaru
imaging surveys. The line diagnostics of the rest-frame optical lines suggests
that only one [O III] blob, OIIIB-3, presents an AGN signature, indicating that
hot gas of the rest of the [O III] blobs is heated by star formation. One of
such star-forming [O III] blobs, OIIIB-4, at z=0.838 has an [O III] equivalent
width of $845pm27$ r{A} and an [O III] to [O II]$lambdalambda$3726,3729
ratio of [O III]/[O II]= $6.5pm2.7$ that are as high as those of typical green
peas (Cardamone et al. 2009). The spatially resolved spectrum of OIIIB-4 shows
[O III]/[O II]= $5-10$ over $14$ kpc in the entire large [O III] extended
regions of OIIIB-4, unlike the known green peas whose strong [O III] emission
region is compact. Moreover, OIIIB-4 presents no high ionization emission lines
unlike green beans that have extended [O III] emission with a type-2 AGN.
OIIIB-4 is thus a giant green pea, which is a low stellar mass ($7times10^7$
$M_odot$) galaxy with a very high specific star formation rate (sSFR =
$2times10^2, {rm Gyr}^{-1}$), a high ionization parameter ($q_{ion} sim
3times10^8, {rm cm,s^{-1}}$), and a low metallicity ($12+log{rm
(O/H)}=7.7$) similar to those of green peas. Neither an AGN-light echo nor a
fast radiative shock likely takes place due to the line diagnostics for
spatially-resolved components of OIIIB-4 and no detections of He
II$lambda$4686 or [Ne V]$lambdalambda$3346,3426 lines that are
fast-radiative shock signatures. There is a possibility that the
spatially-extended [O III] emission of OIIIB-4 is originated from outflowing
gas produced by the intense star formation in a density-bounded ionization
state.

We present the results of the deep Subaru/FOCAS and Keck/MOSFIRE spectroscopy
for four spatially extended [O III]$lambdalambda$4959,5007 sources, dubbed [O
III] blobs, at z=0.6-0.8 that are originally pinpointed by large-area Subaru
imaging surveys. The line diagnostics of the rest-frame optical lines suggests
that only one [O III] blob, OIIIB-3, presents an AGN signature, indicating that
hot gas of the rest of the [O III] blobs is heated by star formation. One of
such star-forming [O III] blobs, OIIIB-4, at z=0.838 has an [O III] equivalent
width of $845pm27$ r{A} and an [O III] to [O II]$lambdalambda$3726,3729
ratio of [O III]/[O II]= $6.5pm2.7$ that are as high as those of typical green
peas (Cardamone et al. 2009). The spatially resolved spectrum of OIIIB-4 shows
[O III]/[O II]= $5-10$ over $14$ kpc in the entire large [O III] extended
regions of OIIIB-4, unlike the known green peas whose strong [O III] emission
region is compact. Moreover, OIIIB-4 presents no high ionization emission lines
unlike green beans that have extended [O III] emission with a type-2 AGN.
OIIIB-4 is thus a giant green pea, which is a low stellar mass ($7times10^7$
$M_odot$) galaxy with a very high specific star formation rate (sSFR =
$2times10^2, {rm Gyr}^{-1}$), a high ionization parameter ($q_{ion} sim
3times10^8, {rm cm,s^{-1}}$), and a low metallicity ($12+log{rm
(O/H)}=7.7$) similar to those of green peas. Neither an AGN-light echo nor a
fast radiative shock likely takes place due to the line diagnostics for
spatially-resolved components of OIIIB-4 and no detections of He
II$lambda$4686 or [Ne V]$lambdalambda$3346,3426 lines that are
fast-radiative shock signatures. There is a possibility that the
spatially-extended [O III] emission of OIIIB-4 is originated from outflowing
gas produced by the intense star formation in a density-bounded ionization
state.

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