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We present a multi-wavelength study of the active galactic nucleus in the nearby ($D=14.1$ Mpc) low mass galaxy IC 750, which has circumnuclear 22 GHz water maser emission. The masers trace a nearly edge-on, warped disk $\sim$0.2 pc in diameter, coincident with the compact nuclear X-ray source which lies at the base of the $\sim$kpc-scale extended X-ray emission. The position-velocity structure of the maser emission indicates the central black hole (BH) has a mass less than $1.4 \times 10^5~M_\odot$. Keplerian rotation curves fitted to these data yield enclosed masses between $4.1 \times 10^4~M_\odot$ and $1.4 \times 10^5~M_\odot$, with a mode of $7.2 \times 10^4~M_\odot$. Fitting the optical spectrum, we measure a nuclear stellar velocity dispersion $\sigma_* = 110.7^{+12.1}_{-13.4}$~{\rm km~s}$^{-1}.$ From near-infrared photometry, we fit a bulge mass of $(7.3 \pm 2.7) \times 10^8~M_\odot$ and a stellar mass of $1.4 \times 10^{10}~M_\odot$. The mass upper limit of the intermediate mass black hole in IC 750 falls roughly two orders of magnitude below the $M_{\rm BH}-\sigma_*$ relation and roughly one order of magnitude below the $M_{\rm BH}-M_{\rm Bulge}$ and $M_{\rm BH}-M_*$ relations -- larger than the relations' intrinsic scatters of (0.58 $\pm$ 0.09) dex, 0.69 dex, and (0.65 $\pm$ 0.09) dex, respectively. These offsets could be due to larger scatter at the low mass end of these relations. Alternatively, black hole growth is intrinsically inefficient in galaxies with low bulge and/or stellar masses, which causes the black holes to be under-massive relative to their hosts, as predicted by some galaxy evolution simulations., Comment: Accepted for publication in ApJ

Here we present the first results from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) which aims to investigate the physics of ~140 radio-detected southern active Galaxies with z, Comment: 6 pages, 2 figures, Invited Talk at the IAU symposium 309

Nuclear black holes in dwarf galaxies are important for understanding the low end of the supermassive black hole mass distribution and the black hole-host galaxy scaling relations. IC 750 is a rare system which hosts an AGN, found in ˜0.5% of dwarf galaxies, with circumnuclear 22 GHz water maser emission, found in ˜3–5% of Type 2 AGNs. Water masers, the only known tracer of warm, dense gas in the center parsec of AGNs resolvable in position and velocity, provide the most precise and accurate mass measurements of SMBHs outside the local group. We have mapped the maser emission in IC 750 and find that it traces a nearly edge-on warped disk, 0.2 pc in diameter. The central black hole has an upper limit mass of ˜1 × 105 M⊙ and a best fit mass of ˜8 × 104 M⊙, one to two orders of magnitude below what is expected from black hole-galaxy scaling relations. This has implications for models of black hole seed formation in the early universe, the growth of black holes, and their co-evolution with their host galaxies.

We have constructed an all-sky catalog of optical AGNs with $z < 0.09$, based on optical spectroscopy, from the parent sample of galaxies in the 2MASS Redshift Survey (2MRS), a near-complete census of the nearby universe. Our catalog consists of 1929 broad line AGNs, and 6562 narrow line AGNs which satisfy the \citet{Kauffmann03} criteria, of which 3607 also satisfy the \citet{Kewley01} criteria. We also report emission line widths, fluxes, flux errors, and signal-to-noise ratios of all the galaxies in our spectroscopic sample, allowing users to customize the selection criteria. Although we uniformly processed the spectra of galaxies from a homogeneous parent sample, inhomogeneities persist due to the differences in the quality of the obtained spectra, taken with different instruments, and the unavailability of spectra for $\sim$20\% of the galaxies. We quantify how the differences in spectral quality affect not only the AGN detection rates but also broad line to narrow line AGN ratios. We find that the inhomogeneities primarily stem from the continuum signal-to-noise (S/N) in the spectra near the emission lines of interest. We fit for the AGN fraction as a function of continuum S/N and assign AGN likelihoods to galaxies which were not identified as AGNs using the available spectra. This correction results in a catalog suitable for statistical studies. This work also paves the way for a truly homogeneous and complete nearby AGN catalog by identifying galaxies whose AGN status needs to be verified with higher quality spectra, quantifying the spectral quality necessary to do so., 30 pages, 24 figures, 5 tables

Studies discerning whether there is a significant correlation between UHECR arrival directions and optical AGN are hampered by the lack of a uniformly selected and complete all-sky optical AGN catalog. To remedy this, we are preparing such a catalog based on the 2MASS Redshift Survey (2MRS), a spectroscopic sample of $\sim 44,500$ galaxies complete to a K magnitude of 11.75 over 91% of the sky. We have analyzed the available optical spectra of these 2MRS galaxies ($\sim 80$% of the galaxies), in order to identify the AGN amongst them with uniform criteria. We present a first-stage release of the AGN catalog for the southern sky, based on spectra from the 6dF Galaxy survey and CTIO telescope. Providing a comparably uniform and complete catalog for the northern sky is more challenging because the spectra for the northern galaxies were taken with different instruments., 8 pages, 5 figures, Proceedings of The 34th International Cosmic Ray Conference

We have conducted a study to quantify the systematic differences resulting from using different stellar population models in optical spectroscopic identification of type II AGN. We examined the different AGN detection fractions of 7069 nearby galaxies (z = 10^40 erg s-1 and increasing to ~ 50% for L[OIII]5007, 21 pages, 20 figures, 1 table; accepted for publication in The Astrophysical Journal

We confirm the UHECR horizon established by the Pierre Auger Observatory using the heterogeneous Veron-Cetty Veron (VCV) catalog of AGNs, by performing a redshift-angle-IR luminosity scan using PSCz galaxies having infrared luminosity greater than 10^{10}L_sun. The strongest correlation -- for z < 0.016, psi = 2.1 deg, and L_ir > 10^{10.5}L_sun -- arises in fewer than 0.3% of scans with isotropic source directions. When we apply a penalty for using the UHECR energy threshold that was tuned to maximize the correlation with VCV, the significance degrades to 1.1%. Since the PSCz catalog is complete and volume-limited for these parameters, this suggests that the UHECR horizon discovered by the Pierre Auger Observatory is not an artifact of the incompleteness and other idiosyncrasies of the VCV catalog. The strength of the correlation between UHECRs and the nearby highest-IR-luminosity PSCz galaxies is stronger than in about 90% percent of trials with scrambled luminosity assignments for the PSCz galaxies. If confirmed by future data, this result would indicate that the sources of UHECRs are more strongly associated with luminous IR galaxies than with ordinary, lower IR luminosity galaxies., 4 pages, 3 figures. Replaced with accepted version

The Pierre Auger Observatory reports that 20 of the 27 highest energy cosmic rays have arrival directions within 3.2 deg of a nearby galaxy in the Veron-Cetty & Veron Catalog of Quasars and Active Galactic Nuclei (12th Ed.), with ~5 of the correlations expected by chance. In this paper we examine the correlated galaxies to gain insight into the possible UHECR sources. We find that 14 of the 21 correlated VCV galaxies are AGNs and we determine their bolometric luminosities. The remaining 7 are primarily star-forming galaxies. The bolometric luminosities of the correlated AGNs are all greater than 5 x 10^{42} erg/s, which may explain the absence of UHECRs from the Virgo region in spite of the large number of VCV galaxies in Virgo, since most of the VCV galaxies in the Virgo region are low luminosity AGNs. Interestingly, the bolometric luminosities of most of the AGNs are significantly lower than required to satisfy the minimum condition for UHECR acceleration in a continuous jet. If a UHECR-AGN correlation is substantiated with further statistics, our results lend support to the recently proposed ``giant AGN flare" mechanism for UHECR acceleration., 13 pages, 3 figures, to be submitted to ApJ

We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3m telescope to obtain spectra with a spectral resolution of R = 7000 in the red (540 - 700 nm) and R = 3000 in the blue (350 - 570 nm), over an integral field of 25x38 arcsec^2 with 1x1 arcsec^2 spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [FeVII]6087 is shown to be correlated with [OIII]/Hbeta. Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects., 37 pages, 18 figures, 4 tables. Accepted for ApJSS. Data release available at: https://datacentral.aao.gov.au/asvo/surveys/s7/

We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-AGN mixing curves on standard emission line diagnostic diagrams which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ~ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ~ 0 to -3.4, 9 pages, 4 figures, accepted for publication in ApJ