A Uniformly Selected, All-Sky, Optical AGN Catalog. (arXiv:1902.03799v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zaw_I/0/1/0/all/0/1">Ingyin Zaw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_Y/0/1/0/all/0/1">Yan-Ping Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Farrar_G/0/1/0/all/0/1">Glennys R Farrar</a>
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.
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.
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