Chapter3.tex

\chapter{Study of AGN radiative mode feedback in NGC 3982\protect\footnote[2]{The contents of this chapter are published in \cite{joseph2022active}}}

\label{Chap3}
\lhead{\emph{Chapter 3: Study of AGN radiative mode feedback in NGC 3982}} % Write in your own chapter title to set the page header
\noindent
\justify

\section{Introduction}

NGC 3982 (UGC 6918) is a nearby late-type galaxy.
It is classified as a Seyfert 1.9 type galaxy based on the optical spectra \citep{veron2010catalogue}.
The galaxy hosts a heavily obscured AGN which is estimated to have an X-ray luminosity, L$_{\text{(2-10 KeV)}}$, of 10$^{42.83}$ erg s$^{-1}$ \citep{saade2022nustar}.
Very-long-baseline interferometry (VLBI) observations of NGC 3982 in 1.7 and 5 GHz reveal that there could be jet or outflow structures on milliarcsecond scales \citep{bontempi2012physical}.
The radio luminosity measured at 5 GHz, L$_{\text{(5 GHz)}}$, is $\sim$10$^{36}\ \text{erg}\ \text{s}^{-1}$.
\cite{gonzalez1993star} noted the presence of circum-nuclear star formation in the galaxy.
The galaxy has a redshift of 0.00371 \citep{accetta2022seventeenth}, and this corresponds to a distance of 15.6 Mpc \citep{wright2006cosmology}.
At this distance, one arcsecond in the sky corresponds to 0.076 kpc.

\cite{saade2022nustar} list the NGC 3982 Eddington ratio as $\sim$10\%. Therefore, it is likely that radiative mode of AGN feedback is present in the galaxy.
AGN in radiative mode can impart energy on the host galaxy and this process leaves behind observational signatures
that could be identified.
The gas around AGN will be ionised by the large energy throughput and produce excitation lines that can be spatially mapped.
Similarly, star formation can be suppressed or triggered in the galaxy, which can be observed via the absence or presence of emitted UV flux associated with star formation activity.

Integral field unit (IFU) based spectroscopy of a galaxy disk allows us to spatially resolve the excitation mechanisms present in the galaxy---this is particularly useful in identifying the extent of AGN-excited regions.
The UV imaging data directly probe recent star
formation (< 200 Myr, \citealt{kennicutt2012star}),
and any effect of AGN feedback
on the galaxy should be revealed in
UV images as reduced flux due to suppressed star formation.
Integral field unit observations from Mapping Nearby Galaxies at APO (MaNGA) and UV data from GALEX or UVIT missions can be used to check for possible spatial evidence of AGN feedback \citep{martin2005galaxy, bundy2014overview, gunn20062, drory2015manga, smee2013multi, tandon2017orbit}.

This chapter gives the study of the AGN activity impact on star
formation using MaNGA and GALEX data (UVIT data was not available at the time of study).

\section{Data and analysis}

\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/hexagon_overlay.png}
	\caption{SDSS \textit{urz} colour image of NGC 3982.
		The \textit{u} filter is shown in blue, \textit{r}
		is in green, and \textit{z} is in red.
		We note the blue regions surrounding the relatively
		redder nuclear region.
		The MaNGA IFU hexagonal aperture
		field of view is overlaid in red.
	}
	\label{fig:heaxagon}
\end{figure}

\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/bpt_classification.png}
	\caption{BPT diagram for NGC 3982 showing
		$[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
		$[\text{N\,\textsc{ii}}]/\text{H}{\alpha}$, $[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
		$[\text{S\,\textsc{ii}}]/\text{H}{\alpha}$, and $[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
		$[\text{O\,\textsc{i}}]/\text{H}{\alpha}$
		plots.
		\textit{Left}: MaNGA spaxels classified into
		star-forming (SF), AGN, composite
		(AGN + SF), and ambiguous categories.
		\textit{Middle and Right}: MaNGA spaxels
		categorised as SF, Seyfert, and LINER.
	}
	\label{fig:bpt}
\end{figure}

\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/BPT_main_plot.png}
	\caption{Spaxel BPT diagram classification of
		Fig.~\ref{fig:bpt}.
		The figure origin coincides
		with the galaxy centre.
		North is up, and east is towards the
		left.
		The angular offsets from the origin
		are given in the top and right
		axes.
		The angular offsets have been
		converted to kiloparsec scales, shown at the bottom and left axes.
		Star-forming (cyan), composite (green),
		ambiguous (grey), and AGN (red) categories
		are shown.}
	\label{fig:bpt_spaxel}
\end{figure}

The MaNGA survey observed galaxies
up to redshift z $\sim$ 0.03.
There are 10010 unique galaxies
in the final MaNGA data release, DR17
\citep{accetta2022seventeenth}.
The reduced MaNGA data have a median
angular resolution of
2.54 arcseconds \citep{law2016drp}.
A detailed description of the MaNGA sample design
can be found in \cite{wake2017sampledesign}.
NGC 3982 was observed
with a 127-fibre IFU of 32 arcseconds diameter
as part of the MaNGA survey (Manga-ID: 1-189584).
The SDSS \textit{urz} colour image cutout of NGC 3982
with the MaNGA IFU hexagonal aperture is shown in
Fig.~\ref{fig:heaxagon}.

GALEX observed NGC 3982 in the NUV channel
for an effective exposure time  of
$\sim$2200 seconds
(GALEX tile: GI6\_012039\_HRS74\_75).
We accessed the NUV imaging data from the
Mikulski Archive for Space Telescopes (MAST)
GALEX archive (no FUV data were available).
The MaNGA resolution corresponds to 0.193 kpc,
and the GALEX NUV resolution is 0.403 kpc at
the galaxy's distance.

We checked the nature and extent of AGN
ionisation in the central region of NGC 3982 as
described below.
The MaNGA data-analysis pipeline (DAP)
generates secondary data products derived
from MaNGA spectroscopy \citep{westfall2019dap}.
The stellar and emission-line
kinematics are derived using penalised
pixel-fitting (PPXF) software
by simultaneously fitting a modified
MILES stellar library and Gaussian emission-line
templates to the MaNGA spectra (the PPXF
software employs a maximum penalised likelihood approach
to fit templates to spectra; \citealt{cappellari2017ppxf,
	westfall2019dap,
	sanchez2006medium,
	falcon2011updated}).
MaNGA DAP products are accessible through
\texttt{Marvin} software \citep{cherinka2019marvin}.
MaNGA DAP-generated maps of
H${\alpha}$,
H${\beta}$,
$[\text{O\,\textsc{iii}}] \ \lambda5007$,
$[\text{O\,\textsc{i}}]\ \lambda6300$,
$[\text{N\,\textsc{ii}}]\ \lambda6584$, and
$[\text{S\,\textsc{ii}}]\ \lambda\lambda6717, 6731$
emission line intensities were used in our subsequent analysis.
To make a spaxel map of the present gas excitation
mechanisms,
we created a Baldwin-Phillips-Terlevich
(BPT) diagram for NGC 3982
using the \texttt{get\_bpt} function of \texttt{Marvin}
\citep{baldwin1981classification}.
\texttt{Marvin} uses the classification system
of \cite{kewley2006host}
and all three diagnostic criteria
from
$[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
$[\text{N\,\textsc{ii}}]/\text{H}{\alpha}$, $[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
$[\text{S\,\textsc{ii}}]/\text{H}{\alpha}$, and $[\text{O\,\textsc{iii}}]/\text{H}{\beta}$ versus
$[\text{O\,\textsc{i}}]/\text{H}{\alpha}$
plots.
It labels MaNGA spaxels as
star-forming (SF), AGN, or composite
(AGN + SF).
The function marks spaxels as ambiguous when it fails
to classify them into one of these three categories.
Seyfert galaxy (Seyfert) and low-ionisation narrow
emission-line region (LINER) classification is also
carried out.
A detailed explanation of the function
can be found on the \texttt{Marvin}
documentation website\footnote{\url{https://sdss-marvin.readthedocs.io/en/latest/tools/bpt.html}}.
The generated BPT diagram is shown in
Fig.~\ref{fig:bpt}, and the on-sky map of
spaxel classification in Fig.~\ref{fig:bpt_spaxel}.

We used the GALEX NUV band image to find the
spatial distribution of recent star formation.
The GALEX NUV image pixel units are in
counts per second (CPS), which we converted
to flux using the unit conversion factor given in \citet{morrissey2007calibration}:
\begin{equation}
	\text{F}_{\text{NUV}} =  2.06 \times 10^{-16} \times \text{CPS}
	,\end{equation}
where $\text{F}_{\text{NUV}}$ is the NUV flux
in erg s$^{-1}$ cm$^{-2}$ \AA$^{-1}$.
The image in CPS units was subtracted
for background before flux conversion.
The NUV flux was corrected for Galactic extinction
by adopting a \cite{cardelli1989relationship} law
with A$_{\text{V}}$ = 0.0437 \citep{schlegel1998maps}
and R$_{\text{V}}$ = 3.1.
The dust present in NGC 3982 can attenuate
the observed NUV band fluxes, leading
to inaccurate interpretation.
Therefore, we need to understand the spatial
variation of dust attenuation levels, especially
in the galaxy's central regions.
We used the Balmer decrement, the ratio between two
H$\alpha$ and H$\beta$ emission line flux values,
to estimate the dust attenuation.
We created the observed Balmer decrement map
by calculating the ratio between observed
$\text{H}{\alpha}$ and $\text{H}{\beta}$
emission line maps,
$(\text{H}{\alpha} / \text{H}{\beta})_{\text{obs}}$.
Equation 4 from \cite{dominguez2013dust}
was then used to convert the Balmer decrement
to a colour excess map:
\begin{equation}
	E(B-V) = 1.97\ \text{log}_{10} \left[ \frac{(\text{H}{\alpha} /
			\text{H}{\beta})_{\text{obs}}}
		{(\text{H}{\alpha} /
			\text{H}{\beta})_{\text{int}}} \right]
	,\end{equation}
where $E(B-V)$ is the colour excess map and
$(\text{H}{\alpha} / \text{H}{\beta})_{\text{int}}$
is the expected Balmer decrement map without dust
attenuation.
We used
$(\text{H}{\alpha} /
	\text{H}{\beta})_{\text{int}}$ = 3.1
for spaxels falling inside
the AGN region of Fig.~\ref{fig:bpt_spaxel}
and 2.86 for the remaining ones \citep{groves2012balmer}.
Finally, we converted the colour excess map
to an A$_{\text{NUV}}$ map (NUV band
attenuation in magnitude) using a
Calzetti attenuation law \citep{calzetti2000dust}:
\begin{equation}
	\text{A}_{\text{NUV}} = k_{\text{NUV}} \times E(B-V)
	,\end{equation}
where $k_{\text{NUV}}$ is the value on the
Calzetti reddening curve evaluated at
the NUV effective wavelength (2315.7 $\angstrom$).
We find from the A$_{\text{NUV}}$ map
(see Fig.~\ref{fig:A_NUV}) that
the outer and central regions have comparable
attenuation levels, with a median A$_{\text{NUV}}$
value of 2.04 in the central AGN ionised regions
and 2.15 in the galaxy disk.

To correct attenuation by dust in NGC 3982,
we used the A$_{\text{NUV}}$ map.
The extinction- and attenuation-corrected
NUV flux was calculated using
\begin{equation}
	\text{F}_{\text{NUV, corrected}} =
	\text{F}_{\text{NUV}}\times
	10^{0.4(\text{A}_{\text{NUV, Galactic}}\
	+\ \text{A}_{\text{NUV}})}
	,\end{equation}
where $\text{F}_{\text{NUV}}$ is the NUV flux,
$\text{A}_{\text{NUV, Galactic}}$ is the Galactic
extinction in the NUV band, and
$\text{F}_{\text{NUV, corrected}}$ is the
extinction- and attenuation-corrected NUV flux.
The A$_{\text{NUV}}$ map created from the
MaNGA data only covers the footprint shown in
Fig.~\ref{fig:heaxagon},
which we need to extrapolate to the full galaxy
to get the integrated extinction.
Therefore, we used the median value of
the A$_{\text{NUV}}$ map for the full
extent of the NUV image of the galaxy.
We note that this estimate should be
considered a lower limit.
The median value suggests that the flux could be attenuated by at least a factor of 7.2.

The NUV band luminosity, $\text{L}_\text{NUV}$,
was calculated using\begin{equation}
	\text{L}_\text{NUV} = 4\pi\ \text{D}^2\ \text{F}_{\text{NUV, corrected}}
	,\end{equation}
where D is the distance and $\text{F}_{\text{NUV, corrected}}$ is the attenuation-corrected flux.
The NUV band luminosity is in erg s$^{-1}$.
The NUV luminosity was converted to the star
formation rate (SFR), assuming constant
star formation for 10$^8$ yr.
Equation 4 from \cite{cortese2008ultraviolet}
was used to derive the SFR from $\text{L}_{\text{NUV}}$:
\begin{equation}
	\text{SFR}\ (\text{M}_{\odot}\text{yr}^{-1}) =
	\frac{\text{L}_\text{NUV}} {3.83 \times 10^{33}} \times 10^{-9.33}
	.\end{equation}
Figure~\ref{fig:nuv} shows the NUV-derived
SFR surface map of the galaxy.
A boundary contour encompassing the composite
and AGN regions from Fig.~\ref{fig:bpt_spaxel}
is overlaid on the figure.
Also shown in the figure is the hexagonal
aperture footprint of the MaNGA IFU.
The cavity region in the centre matches
the composite and AGN photoionised region.
We estimated the median SFR density observed
in the cavity and the ring-shaped
region---there is a factor of $\sim$2 reduction
in the SFR density of the cavity region compared
to the ring-shaped region.

To check whether the lack of a full
disk attenuation map of the galaxy affects our
interpretation of the observed cavity region
in the centre, we created an azimuthally
averaged flux profile of the galaxy using
the NUV image as follows.
The axis ratio and position angle
of NGC 3982 were found on the
NASA/IPAC Extragalactic Database (NED) website\footnote{\url{https://ned.ipac.caltech.edu/byname?objname=ngc+3982}}.
Multiple elliptical apertures were defined
centred on NGC 3982 with an axis ratio
of 0.901 and a position angle of 14.5$\degree$,
each separated by 1.5 arcseconds along
the minor axis.
The apertures were placed at up to $\sim$0.4 arcminutes (2 kpc),
and NUV fluxes were estimated.
Then the differences between the aperture fluxes
were found to get the annuli fluxes.
Finally, annuli average fluxes were found by
dividing by the annuli area.
The annuli average flux is plotted as a function
of distance from the galaxy centre in
Fig.~\ref{fig:annuli_average}.
Similarly, elliptical apertures were used
on the A$_{\text{NUV}}$ map to estimate the
annuli average attenuation levels.
These levels were then used
to correct the annuli average flux values.
Attenuation-corrected annuli average fluxes are
also plotted in Fig.~\ref{fig:annuli_average}.
We note that the A$_{\text{NUV}}$ map only covers
the central region of the NUV image.
Therefore, we can correct NUV fluxes
for attenuation  up to $\sim$0.2 arcminutes.
We stress that attenuation does not
affect the NUV profile of the galaxy's
central region, as demonstrated in
Fig.~\ref{fig:annuli_average}.

We used Very Large Array Sky Survey (VLASS2.1)
2-4 GHz radio sky survey data with an angular
resolution of $\sim$2.5 arcseconds
\citep{lacy2020karl} to
probe AGN activity in
NGC 3982.
We accessed the Quick Look images
from the VLASS archive\footnote{\url{https://archive-new.nrao.edu/vlass/quicklook/}}.
The VLASS contours are overlaid on the
NUV image in Fig.~\ref{fig:nuv}.
The contours show an elongated structure
lying in a south-east to north-west direction.
Interestingly, VLBI observations of NGC 3982
in 1.7 and 5 GHz using the European VLBI Network reveal that there could be jet or outflow structures on
milliarcsecond scales \citep{bontempi2012physical}.
The VLBI-detected features are also oriented
in a south-east to north-west direction.

$[\text{O\,\textsc{iii}}]$ is a forbidden optical
emission line that is more excited by strong
ionising sources, such as AGN, than star-forming
regions.
Spatially resolved $[\text{O\,\textsc{iii}}]$ flux
and kinematics maps have been used in AGN
feedback studies to trace ionised gas outflows
(e.g., \citealt{shin2019positive, ruschel2021agnifs}).
The $[\text{O\,\textsc{iii}}]$ velocity dispersion in
AGN host galaxies is mostly due to AGN activity
\citep{rakshit2018census, woo2016prevalence}.
The MaNGA DAP maps of $[\text{O\,\textsc{iii}}]$
flux and $[\text{O\,\textsc{iii}}]$-traced ionised gas
velocity dispersion are shown in Fig.~\ref{fig:oiii}.
The velocity dispersion map has been corrected for
instrumental dispersion.


\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/A_NUV.png}
	\caption{ MaNGA A$_{\text{NUV}}$ map
		of NGC 3982.
		The black contour represents the area
		encompassing the composite and AGN regions
		in Fig.~\ref{fig:bpt_spaxel}.
	}
	\label{fig:A_NUV}
\end{figure}

\begin{figure}
	\centering
	\includegraphics[width=0.8\columnwidth]{NGC_3982/NGC_3982_NUV_image_with_BPT_contours.png}
	\caption{ GALEX NUV image of NGC 3982.
		The NUV image pixels in count rates
		have been converted to SFR surface densities
		in $\text{M}_{\odot}\text{yr}^{-1}\text{kpc}^{-2}$.
		The red contour represents the area
		encompassing the composite and AGN regions
		in Fig.~\ref{fig:bpt_spaxel}. The dashed black hexagon is the MaNGA IFU
		field of view.
		VLASS2.1 radio contours (green) with contour levels
		0.0007, 0.0012, 0.0018, and 0.0024 Jy/beam
		and a beamwidth of $\sim$2.5 arcseconds
		are overlaid on the figure.
		The radio data reveal an elongated structure
		lying in the south-east to north-west direction.
		The VLBI-detected jet or outflow direction is
		shown as a vector (white) for comparison.
		The vector has an origin at the flat spectrum core
		profile detected by \protect\cite{bontempi2012physical},
		and it points in the direction of
		their detected steep spectrum feature.
	}
	\label{fig:nuv}
\end{figure}

\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/annuli_averaged_values.png}
	\caption{Azimuthally averaged NUV flux profile
		of the galaxy.
		Both attenuation-corrected and uncorrected
		flux profiles are shown.
	}
	\label{fig:annuli_average}
\end{figure}

\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/3D_plot.png}
	\caption{Snapshot from the interactive
		3D visualisation of the SFR surface
		density profile of NGC 3982.
		The visualisation is hosted at
		\url{https://prajwel.github.io/NGC3982/}.
	}
	\label{fig:3dplot}
\end{figure}


\section{Discussion}

The NUV band directly traces stars formed over the last 200 Myr and, therefore, probes recent star formation \citep{kennicutt2012star}.
The GALEX NUV-derived profile of SFR surface density shows recent star formation in a ring-like region around the centre of NGC 3982 (see Fig.~\ref{fig:nuv}).
We also created an interactive 3D visualisation\footnote{The visualisation is hosted at \url{https://prajwel.github.io/NGC3982/}} of the SFR surface density profile.
A snapshot from the interactive plot is shown in Fig.~\ref{fig:3dplot}.
The 3D visualisation clearly shows the suppression of star formation in the central region of NGC 3982.

The intrinsic UV flux from star-forming
regions can be modified due to dust attenuation.
Even if the central region has the same
levels of intrinsic NUV emission as the
ring-like region, a large attenuation in
the central region can produce the presently
observed NUV profile.
However, the A$_{\text{NUV}}$ map shown
in Fig.~\ref{fig:A_NUV} has comparable
dust attenuation levels in the central
and outer regions, with a median A$_{\text{NUV}}$
value of 2.04 in the central AGN ionised regions
and 2.15 in the galaxy disk.
We do not see large attenuation levels
in the central region.
Also, the $\text{F}_{\text{NUV, corrected}}$
profile of the galaxy closely matches the
$\text{F}_{\text{NUV}}$ profile
(see Fig.~\ref{fig:annuli_average}).
Therefore, dust attenuation of NUV flux
in the galaxy cannot explain the cavity.

%{\bf A comparison of the A$_{\text{NUV}}$ 
%map with the NUV image suggests that it appropriately 
%depicts the attenuation in the NUV band. 
%For example, high levels of NUV emission are 
%observed in the Southeast region, and the 
%corresponding region in A$_{\text{NUV}}$ map 
%has low attenuation levels. 
%A reversed scenario can be seen in the 
%Northeast region. 
%Large attenuation levels are found 
%near the Northeast region, and the same 
%location shows low emission levels
%in the NUV image. 
%The central region does not show high 
%attenuation levels, but the NUV 
%flux in this location is at an even lower 
%level than the highly attenuated 
%Northeast region. 
%Note that the $\text{F}_{\text{NUV, corrected}}$
%profile of the galaxy closely matches the
%$\text{F}_{\text{NUV}}$ profile 
%(see Fig.~\ref{fig:annuli_average}).}

The observed suppression of star formation
should be a real feature, not an artefact
of attenuation.
This suggests that processes in the central
region prevented star formation in the last
200 Myr.
The observed NUV cavity is approximately
shaped like an elongated ellipse.
We estimate that it has major
and minor axis lengths of $\sim$17 and $\sim$8 arcseconds,
respectively
($\sim$1.3/0.6 kpc).
The two distinct observational features
that require explanation are the ring-like
star-forming and star-formation-suppressed
central regions.

The first possible explanation we considered
is the presence of a bar.
Bars are observed to induce star formation
along the co-rotation radius and suppress star
formation inside it \citep{george2020more}.
If present, a bar may produce the observed
NUV profile in the galaxy.
However, \cite{regan1999using} studied the central
region of NGC 3982 using the \textit{Hubble} Space Telescope and ruled out
the presence of even a weak bar.
NGC 3982 hosts an AGN, and the cavity region
is covered by composite and AGN emissions.
% which requires a hot ionising source. 
The boundary contour encompassing
the composite and AGN regions
overlaid in Fig.~\ref{fig:nuv} shows the
extent of AGN ionisation in the galaxy
estimated using a BPT diagram.
AGN are known to suppress star formation
and can also be associated with positive
feedback.
Therefore, the likely mechanism for
star formation suppression in NGC 3982
is a jet or outflow associated with the AGN activity.


% \kg {We now investigate the possibility of finding signatures of past jet activity from radio data}.
The radio observations and $[\text{O\,\textsc{iii}}]$
flux and velocity dispersion maps provide clues
regarding AGN activity.
The VLASS2.1 observations reveal an extended structure
with elongation in the south-east to north-west
direction (see Fig.~\ref{fig:nuv}).
While the $[\text{O\,\textsc{iii}}]$ flux map shows
a symmetrically distributed high
emission at the central region, the velocity
dispersion map shows signs of perturbations
in the gas (see Fig.~\ref{fig:oiii}).
The perturbations are most prominently observed
in the south-east ($\sim$130 km s$^{-1}$) and north-east
($\sim$120 km s$^{-1}$) regions.
The perturbed gas  in the south-east is aligned with the
elongated VLASS radio structure, and the
perturbed gas  in the north-east runs parallel to it.
% These observations indicate
% AGN jet/outflow being present in the 
% galaxy.
These observations clearly show that
the ionised gas is perturbed in the
AGN-dominated region and that such perturbation
may be driven by an AGN jet or outflow.
\cite{brum2017dusty}, who analysed the
ionised gas kinematics, noted that a
mild nuclear outflow could be present in the galaxy.
But compared to other local galaxies hosting
outflows, ionised gas outflow signatures in
NGC 3982 are not prominent \citep{ruschel2021agnifs}.
% Similar to NGC 3982, many galaxies hosting
% outflows may yet to be detected.

The AGN hosted in NGC3982 is classified
as Seyfert 1.9 and has an Eddington ratio of $\sim$10\%.
Therefore, the AGN likely belongs to the radiative-mode population.
Therefore, the galaxy may have an outflow
driven by radiation.
We note that the AGN X-ray luminosity
is $\sim$7 orders of magnitude greater than the
radio luminosity \citep{saade2022nustar, bontempi2012physical}.
Nevertheless, the AGN luminosities in different bands
may vary within a short time span (for example,
3C 273; \citealt{soldi2008multiwavelength}).
A jet may produce outflows with features
similar to that generated by radiation
\citep{cielo2018agn}.
Regardless of the nature of the AGN activity,
NGC 3982 is perhaps one of the best
examples of a nearby low-mass AGN
that affects star formation in the disk.

It is interesting to compare
the NGC 3982 case with other observations
of AGN feedback.
Although the activity is presently not detectable,
the AGN in NGC 7252 could have been active
until recently \citep{schweizer2013iii}
and suppressed star formation in the central
region of the galaxy \citep{ngc7252george2018uvit}.
In NGC 5728, a star-forming
ring with a radius of $\sim$1 kpc  and a cavity is observed, and AGN
outflow is found to be responsible
\citep{shin2019positive}.
Surprisingly, ring-like star formation is
also observed in NGC 7252 and NGC 3982
at a radius of $\sim$1 kpc from the centre.
While all three galaxies may host a ring-like star-forming
region with a radius of
$\sim$1 kpc attributed to AGN feedback,
they differ in galaxy morphology and AGN
activity.


\begin{figure}
	\centering
	\includegraphics[width=\columnwidth]{NGC_3982/oiii_intensity_and_dispersion.png}
	\caption{ MaNGA derived maps of $[\text{O\,\textsc{iii}}]$
		emission line intensity and $[\text{O\,\textsc{iii}}]$ traced
		ionised gas velocity dispersion.
		VLASS2.1 radio contours with contour levels
		0.0007, 0.0012, 0.0018, and 0.0024 Jy/beam
		and a beamwidth of $\sim$2.5 arcseconds
		are overlaid on the second panel in dashed
		black lines.}
	\label{fig:oiii}
\end{figure}

\section{Summary}

In this chapter, we examine the impact of AGN radiative mode feedback on star formation within the Seyfert spiral galaxy NGC 3982.
Our multi-wavelength analysis, incorporating UV imaging, IFU observations, and radio data, provides compelling evidence for star formation suppression due to AGN feedback in the galaxy's central region.
The UV imaging clearly indicates suppressed star formation in this area.
Line diagnostic analysis reveals that the central region, characterized by reduced star formation, is dominated by AGN and composite emission.
This finding is further corroborated by the presence of an AGN jet or outflow, as indicated by radio data and gas velocity dispersion map.
The most plausible explanation for this observed scenario is the suppression of star formation in the central regions due to recent AGN activity feedback.
The ring-like profile of star formation in NGC 3982 adds to the evidence that AGN feedback can generate such profiles, in addition to bars.