Figure 5.
Observed H-alpha
velocity field (left),
rotating disk model
(center), and residual
between the two
(right). The central cross
marks the position of
the nucleus, the white
regions are masked
locations where we
were not able to fit the
emission-line profiles,
and the dotted lines
represent the orientation
of the line of nodes. The
black contours in the
residual map are from
the 3-cm radio image
with the same flux levels
as shown in Figure 1,
and the white contours
show radio contours at
the 1.5 sigma level. The
black asterisks labeled
OH1 and OH2 mark the
position of the maser
sources.
16
σ and [N II]/H-alpha surrounding the radio
emission region, supporting interaction
between the radio plasma and ambient
gas. The two OH masers detected in IRAS
F23199E are observed in the vicinity of these
enhanced σ regions, supporting their as-
sociation with the active nucleus and its in-
teraction with the surrounding gas. The gas
velocity field can be partially reproduced by
rotation in a disk, with residuals along the
north-south direction being tentatively at-
tributed to emission from the front walls of
a bipolar outflow.
The combination of HST images, VLA line
spectroscopy, and Gemini IFU spectroscopy
strongly indicates that, in this system, the
OH megamaser sources are associated with
the AGN rather than star formation.
Analysis of the inner regions of OH mega-
maser galaxies can contribute to our under-
standing the origin of these systems and
provide insights into the star formation and
galaxy evolution processes. Further adap-
tive optics observations with Gemini’s Near-
infrared Integral Field Spectrograph, as well
as spectroscopic observations with integral
field units of next generation telescopes,
will allow a better understanding of the role
AGN play in the gas emission of OH mega-
maser galaxies.
GeminiFocus
Hekatelyne Carpes is a recent PhD graduate at
Universidade Federal de Santa Maria - UFSM,
Brazil. She can be reached at:
[email protected]
Rogemar A. Riffel is an associate professor at
Universidade Federal de Santa Maria - UFSM,
Brazil. He can be reached at [email protected]
References
Skinner, C. J., “A starburst origin of the OH-
megamaser emission from the galaxy Arp220,”
Nature, 386: 472, 1997
Lo, K. Y., “Mega-masers and Galaxies,” Annual
Review of Astronomy and Astrophysics, 43: 625,
2005
Huang,Yong, et al., “OH Megamaser: dense gas
& the infrared radiation field,” Journal of Astro-
physics and Astronomy, 39: 34, 2018
January 2019 / 2018 Year in Review