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Over the past half century, gas outflows and winds have been observed as asymmetric emission lines in a wide range of astrophysical contexts, including galaxies and early-type stars. While P Cygni lines are modeled and understood with physically-motivated profiles under the Sobolev approximation, asymmetric nebular lines are not. Previous studies of galactic outflows using nebular emission lines have made physically unjustified assumptions about the shape of the line profile. These approaches limit assessment of outflow properties and do not connect observations to the underlying physics. The physical complexity of galactic outflows requires a more robust approach. In response to this need, we present a novel profile for modeling nebular emission lines which is generalized yet physically motivated and provides insight into the underlying mechanisms of galactic outflows. To demonstrate the usefulness of this profile, we fit it to the asymmetric nebular lines observed in the nuclear region of Mrk 462, a starburst-AGN composite galaxy. From analysis of the best-fit profile, we conclude that the observed profile arises from a dusty radiation-pressure-driven outflow with a terminal velocity of 750 km s-1. This outflow, while weak by some standards, is still sufficiently strong to regulate star formation and black hole growth in the host galaxy by removing gas from the inner few kiloparsecs. Outflows like the one we observe and characterize in Mrk 462 are crucial to our understanding of episodic gas-fueled activity in galactic nuclei, which undoubtedly plays a pivotal role in galaxy evolution., Comment: MNRAS accepted, 12 pages, 9 figures, software available at https://github.com/sflury/OutLines

The Sloan Digital Sky Survey (SDSS) has proved to be a powerful resource for understanding the physical properties and chemical composition of star-forming galaxies in the local universe. The SDSS population of active galactic nuclei (AGN) remains as of yet less explored in this capacity. To extend the rigorous study of \ion{H}{ii} regions in the SDSS to AGN, we adapt methods for computing direct-method chemical abundances for application to the narrow-line regions (NLR) of AGN. By accounting for triply-ionized oxygen, we are able to more completely estimate the total oxygen abundance. We find a strong correlation between electron temperature and oxygen abundance due to collisional cooling by metals. Furthermore, we find that nitrogen and oxygen abundances in AGN are strongly correlated. From the metal-temperature relation and the coupling of nitrogen and oxygen abundances, we develop a new, empirically and physically motivated method for determining chemical abundances from the strong emission lines commonly employed in flux-ratio diagnostic diagrams (BPT diagrams). Our approach, which for AGN reduces to a single equation based on the BPT line ratios, consistently recovers direct-method abundances over a 1.5 dex range in oxygen abundance with an rms uncertainty of 0.18 dex. We have determined metallicities for thousands of AGN in the SDSS, and in the process have discovered an ionization-related discriminator for Seyfert and LINER galaxies., Comment: 14 pages, 11 figures

SDSS J015957.64+003310.5 is an X-ray selected, $z=0.31$ AGN from the Stripe 82X survey that transitioned from a Type 1 quasar to a Type 1.9 AGN between 2000 and 2010. This is the most distant AGN, and first quasar, yet observed to have undergone such a dramatic change. We re-observed the source with the double spectrograph on the Palomar 5m telescope in July 2014 and found that the spectrum is unchanged since 2010. From fitting the optical spectra, we find that the AGN flux dropped by a factor of 6 between 2000 and 2010 while the broad H$\alpha$ emission faded and broadened. Serendipitous X-ray observations caught the source in both the bright and dim state, showing a similar 2-10 keV flux diminution as the optical while lacking signatures of obscuration. The optical and X-ray changes coincide with $g$-band magnitude variations over multiple epochs of Stripe 82 observations. We demonstrate that variable absorption, as might be expected from the simplest AGN unification paradigm, does not explain the observed photometric or spectral properties. We interpret the changing state of J0159+0033 to be caused by dimming of the AGN continuum, reducing the supply of ionizing photons available to excite gas in the immediate vicinity around the black hole. J0159+0033 provides insight into the intermittency of black hole growth in quasars, as well as an unprecedented opportunity to study quasar physics (in the bright state) and the host galaxy (in the dim state), which has been impossible to do in a single sources until now., Comment: accepted for publication in ApJ

Using a distance-limited portion of the Sloan Digital Sky Survey (SDSS) Data Release 7, we have identified 28 active galactic nuclei (AGNs) in nearby (d < 80 Mpc) low-mass, low-luminosity dwarf galaxies. The accreting objects at the galaxy centers are expected to be intermediate-mass black holes (IMBHs) with M_BH < 1e6 M_sun. The AGNs were selected using several optical emission-line diagnostics after careful modeling of the continuum present in the spectra. We have limited our survey to objects with spectral characteristics similar to those of Seyfert nuclei, excluding emission-line galaxies with ambiguous spectra that could be powered by stellar processes. The host galaxies in our sample are thus the least massive objects in the very local universe certain to contain central black holes. Given our focus on the nearest objects included in the SDSS, our survey is more sensitive to low-luminosity emission than previous optical searches for AGNs in low-mass galaxies. The [O III] lambda5007 luminosities of the Seyfert nuclei in our sample have a median value of L_5007 = 2e5 L_sun and extend down to 1e4 L_sun. Using published data for broad-line IMBH candidates, we have derived an [O III] bolometric correction of log (L_bol/L_5007) = 3.0 +/- 0.3, which is significantly lower than values obtained for high-luminosity AGNs. Applying this correction to our sample, we obtain minimum black-hole mass estimates that fall mainly in the 10^3 M_sun -- 10^4 M_sun range, which is roughly where the predicted mass functions for different black-hole seed formation scenarios overlap the most. In the stellar mass range that includes the bulk of the AGN host galaxies in our sample, we derive a lower limit on the AGN fraction of a few percent, indicating that active nuclei in dwarf galaxies are not as rare as previously thought., Comment: 41 pages, 10 figures, accepted for publication in The Astronomical Journal

We have discovered an extremely broad, double-peaked H-alpha emission line in the polarized flux spectrum of NGC 2110, establishing that this well-studied Seyfert 2 galaxy contains a disk-like hidden broad-line region (BLR). Several properties of NGC 2110 suggest that it is an obscured twin of Arp 102B, the prototypical double-peaked emission-line active galactic nucleus (AGN). A comparison between our data and previous spectra of NGC 2110 indicates that the double-peaked H-alpha feature is transient. The presence of a disk-like BLR in NGC 2110 has important implications for AGNs: it expands the range of properties exhibited by Seyfert 2 galaxies, and the fact that the BLR is obscured by a torus-like structure provides the first evidence that double-peaked emitters and classical Seyfert nuclei may have the same basic parsec-scale geometry., Comment: 5 pages, including 3 postscript figures. Uses emulateapj. Accepted for publication in ApJ Letters

We have compared the X-ray--to--optical flux ratios (F_x/F_opt) of absorbed active galactic nuclei (AGNs) in the Chandra Deep Field North (CDF-N) with those of nearby, optically classified Seyfert 2 galaxies. The comparison provides an opportunity to explore the extent to which the local population of absorbed AGNs can account for the properties of the distant, spectroscopically ambiguous sources that produce the hard X-ray background. Our nearby sample consists of 38 objects that well represent the local Seyfert 2 luminosity function. Integrated UBVRI photometry and broadband X-ray observations are presented. Using these data, we have simulated the F_x/F_opt ratios that local Seyfert 2s would exhibit if they were observed in the redshift range 0.2 < z < 1.3 as part of the CDF-N. In the simulations we account for the effects of redshift on flux measurements in fixed observed-frame bands, and the way the luminosity function of a given population is sampled in a flux-limited survey like the CDF-N. Overall, we find excellent agreement between our simulations and the observed distribution of F_x/F_opt ratios for absorbed AGNs in the CDF-N. Our analysis has thus failed to reveal any physical differences between the local population of Seyfert 2s and CDF-N sources with similar X-ray properties. These results support the hypothesis that the nuclear emission lines of many distant hard X-ray galaxies are hidden in ground-based spectra due to a combination of observational effects: signal-to-noise ratio, wavelength coverage, and dilution by host-galaxy light., Comment: 36 pages, including 10 figures. Accepted for publication in the Astronomical Journal

The results of spectropolarimetry surveys of obscured AGNs are reviewed, paying special attention to their implications for the existence of two populations of type 2 Seyfert galaxies -- hidden Seyfert 1s and "true" Seyfert 2s. In this context, the results from our Keck spectropolarimetry survey are presented. Similar to previous work, we have detected hidden broad-line regions (HBLRs) in about half of our sample. However, owing to different selection methods, we find that differences in the properties of HBLR and non-HBLR objects are much less pronounced than prior reports have indicated. Spectropolarimetry studies continue to benefit AGN research, as illustrated by the discovery of double-peaked H-alpha emission in the polarized-flux spectrum of NGC 2110., Comment: To appear in "The Central Engine of Active Galactic Nuclei," eds. L.C. Ho and J.-M. Wang (San Francisco: ASP). 10 pages, uses asp2006.sty

We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out over two nights in 2004 April at Lick, Wise, and Kitt Peak Observatories. We obtained V-band and B-band photometry, and spectra over the range 3500-6800 Angstroms. Simultaneous Hubble Space Telescope UV and Chandra X-ray observations are presented in companion papers. Even though NGC 4395 was in an extremely low state of activity, we detect significant continuum variability of 2-10%, increasing toward shorter wavelengths. The continuum light curves, both spectroscopic and photometric, are qualitatively similar to the simultaneous UV and X-ray light curves. Inter-band cross-correlations suggest that the optical continuum emission lags behind the UV continuum emission by 24 +7/-9 min, and that the optical continuum emission lags behind the X-ray continuum emission by 44 +/- 13 min, consistent with a reprocessing model for active galactic nucleus emission. There are also hints of Balmer emission lines lagging behind the optical continuum by an amount slightly larger than the emission-line lag detected in the UV. These results are all similar to those of other Seyfert 1 nuclei. The emission-line lag yields a mass measurement of the central black hole, which although not very significant, is consistent with the value derived from the simultaneous UV data., Comment: 29 pages, 16 figures, emulateapj, accepted for publication in ApJ

We report on two Chandra observations, and a simultaneous Hubble Space Telescope ultraviolet observation, of the dwarf Seyfert 1 galaxy NGC 4395. Each Chandra observation had a duration of ~30 ks, with a separation of ~50 ks. The spectrum was observed to harden between these observations via a scaling down of the soft-band flux. The inter-observation variability is in a different sense to the observed variability within each observation and is most likely the result of increased absorption. Spectral variations were seen during the first observation suggesting that the X-ray emission is produced in more than one disconnected region. We have also re-analyzed a ~17 ks Chandra observation conducted in 2000. During the three Chandra observations the 2-10 keV flux is about a factor of 2 lower than seen during an XMM-Newton observation conducted in 2003. Moreover, the fractional variability amplitude exhibited during the XMM-Newton observation is significantly softer than seen during the Chandra observations. A power-spectral analysis of the first of the two new Chandra observations revealed a peak at 341s with a formal detection significance of 99%. A similar peak was seen previously in the 2000 Chandra data. However, the detection of this feature is tentative given that it was found in neither the second of our two new Chandra observations nor the XMM-Newton data, and it is much narrower than expected. The Hubble Space Telescope observation was conducted during part of the second Chandra visit. A zero-lag correlation between the ultraviolet and X-ray fluxes was detected with a significance of about 99.5%, consistent with the predictions of the two-phase model for the X-ray emission from active galactic nuclei., Comment: 31 pages, 10 figures, accepted for publication in ApJ

A reverberation-mapping program on NGC 4395, the least-luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, yields a measurement of the mass of the central black hole of 360,000 solar masses. The observations consist of two visits of 5 orbits each, in 2004 April and July. During each of these visits, the UV continuum varied by at least 10% (rms) and only C IV 1549 showed corresponding variations large enough to reliably determine the emission-line lag, which was measured to be of order one hour for both visits. The size of the C IV-emitting region is about a factor of three smaller than expected if the slope of the broad-line region radius-luminosity relationship is identical to that for the H-beta emission line. NGC 4395 is underluminous even for its small black hole mass; the Eddington ratio of 0.0012 is lower than that of any other active galactic nucleus for which a black hole mass measurement has been made by emission-line reverberation., Comment: This replacement is an erratum to be published in The Astrophysical Journal. 3 pages, with one replacement figure and one replacement table

The unique eclipsing, weak-lined T Tauri star KH 15D has been detected as an X-ray source in a 95.7 ks exposure from the Chandra X-ray Observatory archives. A maximum X-ray luminosity of 1.5 x 10^{29} erg s$^{-1}$ is derived in the 0.5--8 keV band, corresponding to L_{X}/L_bol = 7.5 x 10^{-5}. Comparison with samples of stars of similar effective temperature in NGC 2264 and in the Orion Nebula Cluster shows that this is about an order of magnitude low for a typical star of its mass and age. We argue that the relatively low luminosity cannot be attributed to absorption along the line of sight but implies a real deficiency in X-ray production. Possible causes for this are considered in the context of a recently proposed eccentric binary model for KH 15D. In particular, we note that the visible component rotates rather slowly for a weak-lined T Tauri star and has possibly been pseudosynchronized by tidal interaction with the primary near periastron.

We present the results of a 17 ks Chandra ACIS-S observation of the nearby dwarf spiral galaxy NGC 4395. Chandra affords the first high-quality, broadband X-ray detection of the active nucleus of this object that is uncontaminated by nearby sources in the field. We find the nuclear X-ray source to be unresolved and confirm the rapid, large-amplitude variability reported in previous studies. The light curve appears to show ~ 11 cycles of a quasi-periodic oscillation with a period of ~ 400 s. If associated with an orbital feature near the innermost stable orbit of the accretion disk, this period would constrain the black-hole mass to be M < 9e5 M_sun. The X-ray spectrum indicates absorption by an ionized medium, and the spectral shape appears to vary over the course of our observation. Contrary to prior reports, however, the spectral variations are uncorrelated with changes in the hard X-ray flux. It is possible that the short-term spectral variability we observe results from column density fluctuations in the ionized absorber. A power-law fit to the spectrum above 1 keV yields a photon index of Gamma ~ 0.6, much flatter than that typically observed in the spectra of Seyfert 1 galaxies. We have ruled out photon pile-up as the cause of the flat spectrum. Even when complex spectral features are considered, the photon index is constrained to be Gamma < 1.25 (90% confidence). Comparing our results with previous determinations of the photon index (Gamma = 1.46 and 1.72), we conclude that the slope of the primary continuum varies significantly on time scales of a year or less. The extreme flatness and dramatic long-term variability of the X-ray spectrum are unprecedented among active galactic nuclei., Comment: 28 pages, including 10 figures. Accepted for publication in The Astronomical Journal

A full understanding of the origin of the hard X-ray background requires a complete and accurate census of the distant galaxies that produce it. Unfortunately, distant X-ray galaxies tend to be very faint at all wavelengths, which hinders efforts to perform this census. This chapter discusses the insights that can be obtained through comparison of the distant population to local X-ray galaxies, whose properties are well characterized. Such comparisons will ultimately aid investigations into the cosmic evolution of supermassive black holes and their environments., Comment: 19 pages, 10 figures, to appear as Chapter 7 in "Supermassive Black Holes in the Distant Universe" (2004), ed. A. J. Barger, Kluwer Academic Publishers, in press

We present a study of the X-ray properties of a volume-limited sample of optically selected emission-line galaxies. The sample is derived from a correlation between the KPNO International Spectroscopic Survey (KISS), an H-alpha-selected objective-prism survey of AGNs and starbursting galaxies, and the ROSAT All-Sky Survey (RASS). After elimination of all spurious matches, we identify 18 ROSAT-detected X-ray sources within the KISS sample in the 0.1-2.4 keV band. Due to soft X-ray selection effects, the majority of the ROSAT sources are Seyfert 1 galaxies. The majority (54%) of the ROSAT-KISS Seyferts are classified as narrow-line Seyfert 1 objects, a relatively high percentage compared to previous objective-prism-selected Seyfert galaxy samples. We estimate the X-ray luminosities of the ROSAT-detected KISS objects and derive volume emissivities of 6.63 x 10^38 ergs/s/Mpc^3 and 1.45 x 10^38 ergs/s/Mpc^3 for the 30 deg and 43 deg survey strips, respectively. For those KISS AGNs not detected by RASS, we use the median L_X/L_H-alpha ratio derived from a previous study to estimate L_X. The total 0.5-2 keV volume emissivity we predict for the overall KISS AGN sample is sufficient to account for 22.1 +/- 8.9% of the soft X-ray background (XRB), averaged over both survey strips. The KISS AGN sample is made up predominantly of intermediate-luminosity Seyfert 2's and LINERs, which tend to be weak soft X-ray sources. They may, however, represent a much more significant contribution to the hard XRB., Comment: 15 pages, including 5 figures and 2 tables. Accepted for publication in December 2002 AJ

We report on observations of a TypeII quasar at redshift z=3.288, identified as a hard X-ray source in a 185 ks observation with the Chandra X-ray Observatory and as a high-redshift photometric candidate from deep, multiband optical imaging. CXOJ084837.9+445352 (hereinafter CXO52) shows an unusually hard X-ray spectrum from which we infer an absorbing column density N(H) = (4.8+/-2.1)e23 / cm2 (90% confidence) and an implied unabsorbed 2-10 keV rest-frame luminosity of L(2-10) = 3.3e44 ergs/s, well within the quasar regime. Hubble Space Telescope imaging shows CXO52 to be elongated with slight morphological differences between the WFPC2 F814W and NICMOS F160W bands. Optical and near-infrared spectroscopy of CXO52 show high-ionization emission lines with velocity widths ~1000 km/s and flux ratios similar to a Seyfert2 galaxy or radio galaxy. The latter are the only class of high-redshift TypeII luminous AGN which have been extensively studied to date. Unlike radio galaxies, however, CXO52 is radio quiet, remaining undetected at radio wavelengths to fairly deep limits, f(4.8GHz) < 40 microJy. High-redshift TypeII quasars, expected from unification models of active galaxies and long-thought necessary to explain the X-ray background, are poorly constrained observationally with few such systems known. We discuss recent observations of similar TypeII quasars and detail search techniques for such systems: namely (1) X-ray selection, (2) radio selection, (3) multi-color imaging selection, and (4) narrow-band imaging selection. Such studies are likely to begin identifying luminous, high-redshift TypeII systems in large numbers. We discuss the prospects for these studies and their implications to our understanding of the X-ray background., Comment: 28 pages, 5 figures; to appear in The Astrophysical Journal

We present a composite 1-10 keV Seyfert 2 X-ray spectrum, derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected. Above ~3 keV, the composite spectrum is inverted, confirming that Seyfert 2 galaxies as a class have the spectral properties necessary to explain the flat shape of the cosmic X-ray background spectrum. Integrating the composite spectrum over redshift, we find that the total emission from Seyfert 2 galaxies, combined with the expected contribution from unabsorbed type 1 objects, provides an excellent match to the spectrum and intensity of the hard X-ray background. The principal uncertainty in this procedure is the cosmic evolution of the Seyfert 2 X-ray luminosity function. Separate composite spectra for objects in our sample with and without polarized broad optical emission lines are also presented., Comment: 11 pages (AASTeX), including 3 figures. Accepted for publication in ApJ Letters

We have examined ROSAT soft X-ray observations of a complete, distance-limited sample of Seyfert and LINER galaxies. X-ray data are available for 46 out of 60 such objects which lie within a hemisphere of radius 18 Mpc. We have constructed radial profiles of the nuclear sources in order to characterize their spatial extent and, in some cases, to help constrain the amount of flux associated with a nuclear point source. PSPC data from ROSAT have been used to explore the spectral characteristics of the objects with sufficient numbers of detected counts. Based on the typical spectral parameters of these sources, we have estimated the luminosities of the weaker sources in the sample. We then explore the relationship between the soft X-ray and H alpha luminosities of the observed objects; these quantities are correlated for higher-luminosity AGNs. We find a weak correlation at low luminosities as well, and have used this relationship to predict L_X for the 14 objects in our sample that lack X-ray data. Using the results of the spatial and spectral analyses, we have compared the X-ray properties of Seyferts and LINERs, finding no striking differences between the two classes of objects. However, both types of objects often exhibit significant amounts of extended emission, which could minimize the appearance of differences in their nuclear properties. The soft X-ray characteristics of the type 1 and type 2 active galaxies in the sample are also discussed. We then compute the local X-ray volume emissivity of low-luminosity Seyferts and LINERs and investigate their contribution to the cosmic X-ray background. The 0.5-2.0 keV volume emissivity of 2.2e38 ergs/s/Mpc^3 we obtain for our sample suggests that low-luminosity AGNs produce at least 9% of the soft X-ray background., Comment: 39 pages (AASTeX), including 8 figures. Accepted for publication in the Astronomical Journal, August 2001

We present an empirical analysis of the integrated X-ray luminosity arising from populations of OB stars. In particular, we utilize results from the All-Sky Monitor on RXTE, along with archival data from previous missions, to assess the mean integrated output of X-rays in the 2-10 keV band from accreting early-type binaries within 3 kpc of the Sun. Using a recent OB star census of the Solar neighborhood, we then calculate the specific X-ray luminosity per O star from accretion-powered systems. We also assess the contribution to the total X-ray luminosity of an OB population from associated T Tauri stars, stellar winds, and supernovae. We repeat this exercise for the major Local Group galaxies, concluding that the total X-ray luminosity per O star spans a broad range from 2 to 20e34 erg/s. Contrary to previous results, we do not find a consistent trend with metallicity; in fact, the specific luminosities for M31 and the SMC are equal, despite having metallicities which differ by an order of magnitude. In light of these results, we assess the fraction of the observed 2-10 keV emission from starburst galaxies that arises directly from their OB star populations, concluding that, while binaries can explain most of the hard X-ray emission in many local starbursts, a significant additional component or components must be present in some systems. A discussion of the nature of this additional emission, along with its implications for the contribution of starbursts to the cosmic X-ray background, concludes our report., Comment: aastex, 30 pages including 2 tables and 1 figure. To appear in ApJ

While NLS1s have been studied intensively at X-ray and optical wavelengths, comparatively little is known about their characteristics in the radio band. Therefore, we have carried out an investigation of the radio luminosities, source sizes, spectral index distribution, and variability of a large, uniformly selected sample of NLS1s. Our results indicate that, in some respects, the radio properties of NLS1s differ significantly from those of classical Seyfert galaxies. Radio observations of NLS1s may thus provide important clues regarding the nature of their nuclear activity., Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-workshop

The infrared-luminous galaxy NGC3256 is a classic example of a merger induced nuclear starburst system. We find here that it is the most X-ray luminous star-forming galaxy yet detected (~10^42 ergs/s). Long-slit optical spectroscopy and a deep, high-resolution ROSAT X-ray image show that the starburst is driving a "superwind" which accounts for ~20% of the observed soft (kT~0.3 keV) X-ray emission. Our model for the broadband X-ray emission of NGC3256 contains two additional components: a warm thermal plasma (kT~0.8 keV) associated with the central starburst, and a hard power-law component with an energy index of ~0.7. We find that the input of mechanical energy from the starburst is more than sufficient to sustain the observed level of emission. We also examine possible origins for the power-law component, concluding that neither a buried AGN nor the expected population of high-mass X-ray binaries can account for this emission. Inverse-Compton scattering, involving the galaxy's copious flux of infrared photons and the relativistic electrons produced by supernovae, is likely to make a substantial contribution to the hard X-ray flux. Such a model is consistent with the observed radio and IR fluxes and the radio and X-ray spectral indices. We explore the role of X-ray-luminous starbursts in the production of the cosmic X-ray background radiation. The number counts and spectral index distribution of the faint radio source population, thought to be dominated by star-forming galaxies, suggest that a significant fraction of the hard X-ray background could arise from starbursts at moderate redshift., Comment: 31 pages (tex, epsf), 8 figures (postscript files), accepted for publication in Part 1 of The Astrophysical Journal

We have detected a broad H alpha emission line in the polarized flux spectrum of the Seyfert 2 galaxy NGC 788, indicating that it contains an obscured Seyfert 1 nucleus. While such features have been observed in ~15 other Seyfert 2s, this example is unusual because it has a higher fraction of galaxy starlight in its spectrum, a lower average measured polarization, and a significantly lower radio luminosity than other hidden Seyfert 1s discovered to date. This demonstrates that polarized broad-line regions can be detected in relatively weak classical Seyfert 2s, and illustrates why well-defined, reasonably complete spectropolarimetric surveys at H alpha are necessary in order to assess whether or not all Seyfert 2s are obscured Seyfert 1s., Comment: 10 pages using (AASTEX) aaspp4.sty and 4 postscript figures. Publications of the Astronomical Society of the Pacific, Research Notes, in press

We present a high-quality X-ray spectrum in the 3--53 keV rest-frame band of the radio-loud quasar 1508+5714, by far the brightest known X-ray source at z > 4. A simple power-law model with an absorption column density equal to the Galactic value in the direction of the source provides an excellent and fully adequate fit to the data; the measured power-law photon index Gamma = 1.42 (+0.13,-0.10). Upper limits to Fe K alpha line emission and Compton-reflection components are derived. We offer evidence for both X-ray and radio variability in this object and provide the first contemporaneous radio spectrum (alpha = -0.25). The data are all consistent with a picture in which the emission from this source is dominated by a relativistically beamed component in both the X-ray and radio bands., Comment: 8 pages, TeX, 2 postscript figures; to appear in ApJ Letters

The broadband X-ray spectrum of the prototypical starburst galaxy M82 is very complex. At least three spectral components are required to fit the combined ROSAT and ASCA spectrum in the 0.1--10 keV range. The observed X-ray flux in this band is dominated by a hard Gamma = 1.7, heavily absorbed power law component which originates in the nucleus and near-nuclear disk of the galaxy. Among the candidates for the origin of this hard X-ray emission, the most plausible appears to be inverse-Compton scattered emission from the interaction of M82's copious infrared photon flux with supernova-generated relativistic electrons. The measured intrinsic luminosity of the power law component agrees closely with calculations of the expected inverse-Compton luminosity. Moreover, the radio and X-ray emission in the nucleus of M82 have the same spectral slope, which should be the case if both types of emission are non- thermal and are associated with a common population of electrons. The other two spectral components, thermal plasmas with characteristic temperatures kT = 0.6 and 0.3 keV, are associated with the star formation and starburst-driven wind in M82. The warmer thermal component is heavily absorbed as well and must also originate in the central region of the galaxy. The softer thermal component, however, is not absorbed, and is likely to represent the X-ray emission which extends along M82's minor axis. The amount of absorption required in the three-component model suggests that the intrinsic luminosity of M82 in the 0.1--10 keV band is about four times greater than its observed luminosity of 4 x 10(40) ergs/s., Comment: 23 pages, TeX, seven postscript figures, three tables Accepted for the March 20, 1997 issue of ApJ