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M. N. Rosli

Publications and source records attributed to M. N. Rosli.

2 recordsLinked to original sources

Nuclear Activity and Host Galaxy Properties of Low-Luminosity AGN Identified from VLA Observations

Low-luminosity active galactic nuclei (LLAGN; $L_{\rm bol} < 10^{42}$~erg~s$^{-1}$) may comprise a significant fraction of the local AGN population, yet their weak emission makes them difficult to detect. In this paper, we analyse 38 LLAGN identified from a 15~GHz sub-arcsecond Very Large Array survey and assess the effectiveness of X-ray, optical, and infrared wavelengths in identifying LLAGN. We found that optical emission-line diagnostics recovered $84.2^{+15.8}_{-22.9}$\% (32/38) of the sample, X-rays detected $63.2^{+25.7}_{-19.6}$\% (24/38), and infrared methods only identified $13.2^{+14.5}_{-8.0}$\% (5/38), reflecting limited X-ray sensitivity, weak or absent optical lines, and strong host galaxy contamination in the infrared. Compared to \textit{Swift}--BAT AGN, our LLAGN are $\sim$ 4.1~dex fainter in bolometric luminosity (log $L_{\mathrm{bol}} \approx$ 39.3 - 41.9 erg s$^{-1}$), host smaller black holes ($\sim$0.7~dex lower), and accrete at much lower rates (log $λ_{\text{Edd}} \approx$ -6.5 to -1.3, i.e., $\sim$ 4.2~dex lower). Host galaxies span a broad range of morphologies, from disk- to bulge-dominated, with a subset exhibiting prominent bulges, potentially representing systems where nuclear activity has faded while the bulge remains dominant. LLAGN also reside in galaxies with lower stellar masses ($\sim$0.3~dex) and suppressed star formation rates ($\sim$0.5~dex) relative to \textit{Swift}--BAT AGN. Overall, LLAGN in our sample systematically host smaller and weakly accreting black holes, residing in galaxies with diverse morphologies, but lower stellar masses and reduced star formation activity, demonstrating the connection between low-level black hole accretion and host galaxy properties in the local Universe.

astro-ph.GA

The Compton-thick AGN Population and the $N_{\rm H}$ Distribution of Low-mass AGN in our Cosmic Backyard

We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density ($N_{\rm{H}}$) distribution of AGN in our cosmic backyard using a mid-infrared selected AGN sample within 15 Mpc. The column densities are measured from broadband X-ray spectral analysis, mainly using data from $\textit{Chandra}$ and $\textit{NuSTAR}$. Our sample probes AGN with intrinsic 2-10 keV luminosities of $L_{\rm 2-10, int} = 10^{37}$-$10^{43}$ erg s$^{-1}$, reaching a parameter space inaccessible to more distant samples. We directly measure a 32$^{+30}_{-18}\%$ CT AGN fraction and obtain an $N_{\rm{H}}$ distribution that agrees with that inferred by the $\textit{Swift}$-BAT survey. Restricting the sample to the largely unexplored domain of low-luminosity AGN with $L_{\rm 2-10, int}$ $\leq$ $10^{42}$ erg s$^{-1}$, we found a CT fraction of 19$^{+30}_{-14}\%$, consistent with those observed at higher luminosities. Comparing the host-galaxy properties between the two samples, we find consistent star formation rates, though the majority of our galaxy have lower stellar masses (by $\approx 0.3$ dex). In contrast, the two samples have very different black hole mass ($M_{\rm BH}$) distributions, with our sample having $\approx$1.5 dex lower mean mass ($M_{\rm BH}$ $\sim$ 10$^{6}$ $M_\odot$). Additionally, our sample contains a significantly higher number of LINERs and H$_{\rm{II}}$-type nuclei. The Eddington ratio range probed by our sample, however, is the same as $\textit{Swift}$-BAT, although the latter dominates at higher accretion rates, and our sample is more evenly distributed. The majority of our sample with $λ_{\rm Edd} \ge$ 10$^{-3}$ tend to be CT, while those with $λ_{\rm Edd} <$ 10$^{-3}$ are mostly unobscured or mildly obscured.

astro-ph.GA