Home and Business Energy Reduction

Course Code: ENR/AEDE 4567The focus of our project is to reduce energy consumption community-wide by 20% over the next five years within the residential and commercial sectors. This 20% reduction is a goal within Green Memo III, set forth by the City of Columbus and Mayor Michael B. Coleman. Focusing on five objectives, we conducted research, gathered data on best practices from cities that have been making strides in this area, reached out to key energy providers, and provided a cost-benefit analysis on the financial feasibility of our goals. We hope to advise Columbus decision makers on how to effectively target homes and commercial buildings in order to market energy efficiency programs. We believe these programs will effectively reduce overall energy consumption and greenhouse gas (GHG) emissions for the City of Columbus.Academic Major: Environment, Economy, Development, and Sustainabilit

The Seyfert-Starburst Connection in X-rays. II. Results and Implications

We present the results of X-ray imaging and spectroscopic analysis of a sample of Seyfert 2 galaxies that contain starbursts, based on their optical and UV characteristics. These composite galaxies exhibit extended, soft, thermal X-ray emission, which we attribute to their starburst components. Comparing their X-ray and far-infrared properties with ordinary Seyfert and starburst galaxies, we identify the spectral characteristics of their various intrinsic emission sources. The observed far-infrared emission of the composite galaxies may be associated almost exclusively with star formation, rather than the active nucleus. The ratio of the hard X-ray luminosity to the far-infrared and [O III] 5007 luminosity distinguishes most of these composite galaxies from ``pure'' Seyfert 2 galaxies, while their total observed hard X-ray luminosity distinguishes them from ``pure'' starbursts. The hard nuclear X-ray source is generally heavily absorbed (N_H > 10^{23} cm^{-2}) in the composite galaxies. Based on these results, we suggest that the interstellar medium of the nuclear starburst is a significant source of absorption. The majority of the sample are located in groups or are interacting with other galaxies, which may trigger the starburst or allow rapid mass infall to the central black hole, or both. We conclude that starbursts are energetically important in a significant fraction of active galaxies, and starbursts and active galactic nuclei may be part of a common evolutionary sequence.Comment: 16 pages including 8 figures and 5 tables; to appear in the ApJ, Mar. 10, 200

A Survey for H2_2O Megamasers in Active Galactic Nuclei -- II. A Comparison of Detected and Undetected Galaxies

A survey for H2O megamaser emission from 354 active galaxies has resulted in the detection of 10 new sources, making 16 known altogether. The galaxies surveyed include a distance-limited sample (covering Seyferts and LINERs with recession velocities < 7000 km s^{-1}) and a magnitude-limited sample (covering Seyferts and LINERs with m(B) <= 14.5). In order to determine whether the H2O-detected galaxies are "typical" AGN or have special properties which facilitate the production of powerful masers, we have accumulated a database of physical, morphological, and spectroscopic properties of the observed galaxies. The most significant finding is that H2O megamasers are detected only in Seyfert 2 and LINER galaxies, not Seyfert 1s. Implications for this finding are discussed. LINERs are detected at a similar rate to Seyfert 2s, constituting a strong argument that at least some nuclear LINERs are AGN rather than starbursts, since starbursts have not been detected as H2O megamasers. We preferentially detect H2O emission from the nearer galaxies and from those which are apparently brighter at mid- and far-infrared and centimeter radio wavelengths. There is also a possible trend for the H2O-detected galaxies to be more intrinsically luminous in nuclear 6 cm radio emission than the undetected ones, though these data are incomplete. We find evidence that Seyfert 2s with very high (N(H) > 10^{24} cm^{-2}) X-ray absorbing columns of gas are more often detected as H2O maser emitters than Seyfert 2s with lower columns. It may be that the probability of detecting H2O maser emission in Seyfert galaxies increases with increasing column of cool gas to the nucleus, from Seyfert 1s through NLXGs to Seyfert 2s.Comment: 19 pages, 35 figures, 3 of the tables are contained in separate LaTeX files: Table 1-a, 1-b, and 3. Also, figure captions are contained in a separate file which must be compiled with plain TeX, not LaTe

The spectral energy distribution of the central parsecs of the nearest AGN

Spectral energy distributions (SEDs) of the central few tens of parsec region of some of the nearest, most well studied, active galactic nuclei (AGN) are presented. These genuine AGN-core SEDs, mostly from Seyfert galaxies, are characterised by two main features: an IR bump with the maximum in the 2-10 micron range, and an increasing X-ray spectrum in the 1 to ~200 keV region. These dominant features are common to Seyfert type 1 and 2 objects alike. Type 2 AGN exhibit a sharp drop shortward of 2 micron, with the optical to UV region being fully absorbed, while type 1s show instead a gentle 2 micron drop ensued by a secondary, partially-absorbed optical to UV emission bump. Assuming the bulk of optical to UV photons generated in these AGN are reprocessed by dust and re-emitted in the IR in an isotropic manner, the IR bump luminosity represents >70% of the total energy output in these objects while the high energies above 20 keV are the second energetically important contribution. Galaxies selected by their warm IR colours, i.e. presenting a relatively-flat flux distribution in the 12 to 60 micron range have often being classified as AGN. The results from these high spatial resolution SEDs question this criterion as a general rule. It is found that the intrinsic shape of the IR SED of an AGN and inferred bolometric luminosity largely depart from those derived from large aperture data. AGN luminosities can be overestimated by up to two orders of magnitude if relying on IR satellite data. We find these differences to be critical for AGN luminosities below or about 10^{44} erg/s. Above this limit, AGNs tend to dominate the light of their host galaxy regardless of the aperture size used. We tentatively mark this luminosity as a threshold to identify galaxy-light- vs AGN- dominated objects.Comment: 50 pages, 14 figures. Accepted for publication in MNRA

A Survey of Kiloparsec-Scale Radio Outflows in Radio-Quiet Active Galactic Nuclei

Seyfert galaxies commonly host compact jets spanning 10-100 pc scales, but larger structures (KSRs) are resolved out in long baseline, aperture synthesis surveys. We report a new, short baseline Very Large Array (VLA) survey of a complete sample of Seyfert and LINER galaxies. Out of all of the surveyed radio-quiet sources, we find that 44% (19 / 43) show extended radio structures at least 1 kpc in total extent that do not match the morphology of the disk or its associated star-forming regions. The KSR Seyferts stand out by deviating significantly from the far-infrared - radio correlation for star-forming galaxies, and they are more likely to have a relatively luminous, compact radio source in the nucleus; these results argue that KSRs are powered by the AGN rather than starburst. KSRs probably originate from jet plasma that has been decelerated by interaction with the nuclear ISM. We demonstrate the jet loses virtually all of its power to the ISM within the inner kiloparsec to form the slow KSRs.Comment: to appear in the Astronomical Journal, Vol 132 (projected

Interview with Kathy & Matt Unger, Unger Farms, 2007 (audio)

Interview of Kathy and Matt Unger by Alix Lefler at Cornelius, Oregon on July 25th, 2007. The interview index is available for download

Neutral Hydrogen (21 Centimeter) Absorption in Seyfert Galaxies: Evidence for Free-Free Absorption and Subkiloparsec Gaseous Disks

Original article can be found at: http://www.journals.uchicago.edu/ApJ/front.html--Copyright American Astronomical SocietyActive galaxies are thought to be both fueled and obscured by neutral gas removed from the host galaxy and funneled into a central accretion disk. We performed a VLA imaging survey of 21 cm absorption in Seyfert and starburst nuclei to study the neutral gas in the near-nuclear environment. With the exception of NGC 4151, the absorbing gas traces 100 pcÈscale, rotating disks aligned with the outer galaxy disk. These disks appear to be rich in atomic gas relative to nuclear disks in nonactive spirals. We Ðnd no strong evidence for rapid infall or outÑow of neutral hydrogen, but our limits on the mass infall rates are compatible with that required to feed a Seyfert nucleus. Among the galaxies surveyed here, neutral hydrogen absorption traces parsec-scale gas only in NGC 4151. Based on the kinematics of the absorption line, the disk symmetry axis appears to align with the radio jet axis rather than the outer galaxy axis. The most surprising result is that we detect no 21 cm absorption toward the central radio sources of the hidden Seyfert 1 nuclei Mrk 3, Mrk 348, and NGC 1068. Moreover, 21 cm absorption is commonly observed toward extended radio jet structure but appears to avoid central, compact radio sources in Seyfert nuclei. To explain these results, we propose that 21 cm absorption toward the nucleus is suppressed by either free-free absorption, excitation e ects (i.e., enhanced spin temperature), or rapid motion in the obscuring gas. Ironically, the implications of these e ects is that the obscuring disks must be small, typically not larger than a few tens of parsecs.Peer reviewe