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Analysis of the recent long exposure Chandra X-ray observation of the early-type O star zeta Pup shows clear variability with a period previously reported in optical photometric studies. These 813 ks of HETG observations taken over a roughly one year time span have two signals of periodic variability: a high significance period of 1.7820 +/- 0.0008 day, and a marginal detection of periodic behavior close to either 5 day or 6 day period. A BRITE-Constellation nanosatellite optical photometric monitoring, using near-contemporaneous observations to the Chandra data, confirms a 1.78060 +/- 0.00088 day period for this star. The optical period coincides with the new Chandra period within their error ranges, demonstrating a link between these two wavebands and providing a powerful lever for probing the photosphere/wind connection in this star. The phase lag of the X-ray maximum relative to the optical maximum is approximately phi=0.45, but consideration of secondary maxima in both datasets indicates possibly two hot spots on the star with an X-ray phase lag of phi=0.1 each. The details of this periodic variation of the X-rays are probed by displaying a phased and trailed X-ray spectrum and by constructing phased light curves for wavelength bands within the HETG spectral coverage, ranging down to bands encompassing groups of emission lines. We propose that the 1.78 day period is the stellar rotation period and explore how stellar bright spots and associated co-rotating interacting regions or CIRs could explain the modulation of the optical and X-ray output for this star and their phase difference., 17 pages; 10 figures

Simultaneous XMM-Newton, NuSTAR and HST observations, performed in March 2017, of the nearby ($z=0.184$) luminous quasar PDS 456 are presented. PDS 456 had a low X-ray flux compared to past observations, where the first of the two new XMM-Newton observations occurred during a pronounced dip in the X-ray lightcurve. The broad-band X-ray spectrum is highly absorbed, attenuated by a soft X-ray absorber of column density $N_{\rm H}=6\times10^{22}$ cm$^{-2}$. An increase in obscuration occurs during the dip, which may be due to an X-ray eclipse. In addition, the persistent, fast Fe K outflow is present, with velocity components of $-0.25c$ and $-0.4c$. The soft absorber is less ionized ($\log\xi=3$) compared to the iron K outflow ($\log\xi=5$) and is outflowing with a velocity of approximately $-0.2c$. A soft X-ray excess is present below 1 keV against the highly absorbed continuum and can be attributed to the re-emission from a wide angle wind. The complex X-ray absorption present in PDS 456 suggests that the wind is inhomogeneous, whereby the soft X-ray absorber originates from denser clumps or filaments which may form further out along the outflow. In contrast to the X-ray observations, the simultaneous UV spectrum of PDS 456 is largely unabsorbed, where only a very weak broad absorption trough is present bluewards of Ly$\alpha$, compared to a past observation in 2000 when the trough was significantly stronger. The relative weakness of the UV absorption may be due to the soft X-ray absorber being too highly ionized and almost transparent in the UV band., Comment: 17 pages, accepted for publication in the Astrophysical Journal

Rich complexes of associated absorption lines (AALs) in quasar spectra provide unique information about gaseous infall, outflows, and feedback processes in quasar environments. We study five quasars at redshifts 3.1 to 4.4 with AAL complexes containing from 7 to 18 CIV 1548, 1551 systems in high-resolution spectra. These complexes span velocity ranges $\lesssim$3600 km/s within $\lesssim$8200 km/s of the quasar redshifts. All are highly ionised with no measurable low-ionisation ions like SiII or CII, and all appear to form in the quasar/host galaxy environments based on evidence for line locking, partial covering of the background light source, strong NV absorption, and/or roughly solar metallicities, and on the implausibility of such complexes forming in unrelated intervening galaxies. Most of the lines in all five complexes identify high-speed quasar-driven outflows at velocity shifts $v\lesssim -1000$ km/s. Four of the complexes also have lines at smaller blueshifted velocities that might form in ambient interstellar clouds, low-speed outflows or at feedback interfaces in the host galaxies where high-speed winds impact and shred interstellar clouds. The partial covering we measure in some of the high-speed outflow lines require small absorbing clouds with characteristic sizes $\lesssim$1 pc or $\lesssim$0.01 pc. The short survival times of these clouds require locations very close to the quasars, or cloud creation in situ at larger distances perhaps via feedback/cloud-shredding processes. The AAL complex in one quasar, J1008+3623, includes unusually narrow CIV systems at redshifted velocities $350\lesssim v\lesssim640$ km/s that are excellent candidates for gaseous infall towards the quasar, e.g., ''cold-mode" accretion or a gravitationally-bound galactic fountain., 23 pages, 8 figures, 7 tables. arXiv admin note: text overlap with arXiv:1809.05433

We have made an extensive study of the UV spectrum of Eta Carinae, and find that we do not directly observe the star and its wind in the UV. Because of dust along our line of sight, the UV light that we observe arises from bound-bound scattering at large impact parameters. We obtain a reasonable fit to the UV spectrum by using only the flux that originates outside 0.033". This explains why we can still observe the primary star in the UV despite the large optical extinction -- it is due to the presence of an intrinsic coronagraph in the Eta Carinae system, and to the extension of the UV emitting region. It is not due to peculiar dust properties alone. We have computed the spectrum of the purported companion star, and show that it could only be directly detected in the UV spectrum preferentially in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectral region (912-1175 Ang.). However, we find no direct evidence for a companion star, with the properties indicated by X-ray studies and studies of the Weigelt blobs, in UV spectra. This might be due to reprocessing of the companion's light by the dense stellar wind of the primary. Broad FeII and [FeII] emission lines, which form in the stellar wind, are detected in spectra taken in the SE lobe, 0.2" from the central star. The wind spectrum shows some similarities to the spectra of the B & D Weigelt blobs, but also shows some marked differences in that high excitation lines, and lines pumped by Ly-alpha, are not seen. The detection of the broad lines lends support to our interpretation of the UV spectrum, and to our model for Eta Carinae., To appear in ApJ. 57 pages with 18 figures

We used a very large set of models of broad emission line (BEL) clouds in AGN to investigate the formation of the observed Fe II emission lines. We show that photoionized BEL clouds cannot produce both the observed shape and observed equivalent width of the 2200-2800A Fe II UV bump unless there is considerable velocity structure corresponding to a microturbulent velocity parameter v_turb > 100 km/s for the LOC models used here. This could be either microturbulence in gas that is confined by some phenomenon such as MHD waves, or a velocity shear such as in the various models of winds flowing off the surfaces of accretion disks. The alternative way that we can find to simultaneously match both the observed shape and equivalent width of the Fe II UV bump is for the Fe II emission to be the result of collisional excitation in a warm, dense gas. Such gas would emit very few lines other than Fe II. However, since the collisionally excited gas would constitute yet another component in an already complicated picture of the BELR, we prefer the model involving turbulence. In either model, the strength of Fe II emission relative to the emission lines of other ions such as Mg II depends as much on other parameters (either v_turb or the surface area of the collisionally excited gas) as it does on the iron abundance. Therefore, the measurement of the iron abundance from the FeII emission in quasars becomes a more difficult problem.

We analyze spectra for a large sample of 578 Active Galactic Nuclei to examine the relationships between broad emission line properties and central supermassive black hole (SMBH) mass. We estimate SMBH masses by applying the virial theorem to the C IV lambda 1549 broad emission line. Although the FWHMs of C IV and H beta appear nearly unrelated in individual objects, these FWHMs are well correlated when averaged over sub-samples in our database. Therefore, the lines are equally valid indicators of the average SMBH mass in quasar samples. Our sample spans five orders of magnitude in SMBH mass, six orders of magnitude in luminosity, and a redshift range from 0, 21 pages, including 11 figures and 2 tables

We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high-velocity (-56,000 km s-1) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to determine the nature of the absorbing gas. The UV and X-ray data sets were not obtained simultaneously. Nonetheless, our analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are not enough constraints to rule out multizone models. In fact, the distinct broad and narrow UV line profiles clearly indicate that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (log U = 1.6, NH = 1022.4 cm-2) overpredict the O VI λλ1032, 1038 absorption unless the X-ray absorber is also outflowing at ~56,000 km s-1, but they overpredict the Ne VIII λλ770, 780 absorption at all velocities. If we assume that the X-ray-absorbing gas is outflowing at the same velocity as the UV-absorbing wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of ≤1015 cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative acceleration.

The intensity of the strong N V 1240 line relative to C IV 1549 or to He II 1640 has been proposed as an indicator of the metallicity of QSO broad emission line regions, allowing abundance measurements in a large number of QSOs out to the highest redshifts. Previously, it had been shown that the (normally) much weaker lines N III] 1750 and N IV] 1486 could be used in the same way. The redshift 1.96 QSO 0353-383 has long been known to have N III] and N IV] lines that are far stronger relative to Ly-alpha or C IV than in any other QSO. Because in this particular case these intercombination lines can be easily measured, this unusual object provides an ideal opportunity for testing whether the N V line is a valid abundance indicator. Using new observations of Q0353-383 made both with HST in the ultraviolet and from the ground in the visible passband, we find that intensity ratios involving the strengths of N V, N IV] and N III] relative to lines of He, C and O all indicate that nitrogen is overabundant relative to oxygen in Q0353-383 by a factor of ~15 compared to solar ratios. This agreement among the diagnostics supports the use of these lines for measuring BLR chemical abundances. If nitrogen behaves like a secondary element, such that N/O is proportional to O/H, then the extreme nitrogen enhancement in Q0353-383 implies a metallicity of ~15 times the solar value. Even if Q0353-383 represents an extreme outlier in the N/O proportional to O/H relation, the overall metallicity should still be at least five times solar. Unusually high metallicities in Q0353-383 might imply that we caught this object just as the gas-phase metallicity in the central part of its host galaxy has peaked, at a time when the interstellar gas supply is nearly exhausted and hence the fuel source for the central QSO is ready to shut off.

We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer (FUSE). We have combined 18 STIS and five FUSE observations to obtain a high signal-to-noise ratio averaged spectrum spanning 905-1730 A. The averaged spectrum reveals absorption in O VI, N V, C IV, N III, C III, and the Lyman lines up to Ly in the three blueshifted kinematic components previously detected in the STIS spectrum (at radial velocities of -1320, -724, and -548 km s-1). The highest velocity component exhibits absorption in Si IV. We also detect metastable C III in this component, indicating a high density in this absorber. No lower ionization lines, i.e., C II and Si II, are detected. A weak, fourth absorption component is tentatively detected in the high-ionization lines and Lyα and Lyβ at a radial velocity of -1027 km s-1. The Lyman lines reveal a complex absorption geometry. The strength of the higher order lines indicates that Lyα and Lyβ are saturated over much of the resolved profiles in the three strongest absorption components and that, therefore, their observed profiles are determined by the covering factor. We separate the individual covering factors of the continuum and emission-line sources as a function of velocity in each kinematic component using the Lyα and Lyβ lines. The covering factor of the broad-line region is found to vary dramatically between the cores of the individual kinematic components, ranging from 0 to 0.84. In addition, we find that the continuum covering factor varies with velocity within the individual kinematic components, decreasing smoothly in the wings of the absorption by at least 60%. Comparison of the effective covering factors derived from the H I results with those determined directly from the doublets reveals that the covering factor of Si IV is less than half that of H I and N V in the high-velocity component. In addition, the FWHMs of N III and Si IV are narrower than those of the higher ionization lines in this component. These results indicate there is substructure within this absorber. We also find evidence for structure in the column density profiles of the high-ionization lines in this component. We derive a lower limit on the total column (NH ≥ 1019 cm-2) and ionization parameter (U ≥ 0.005) in the low-ionization subcomponent of this absorber. The metastable-to-total C III column density ratio implies ne ≈ 109 cm-3 and an upper limit on the distance of the absorber from the ionizing continuum of R ≤ 8 × 1017 cm. The decreasing covering factor found in the wings of the absorption and the extreme compactness of the C III* absorber are suggestive of a clumpy absorption gas with a low volume filling factor.

We show that the mass of ionized gas in the Broad Line Regions (BLRs) of luminous QSOs is at least several hundred Msun, and probably of order 10^3-10^4 M_sun. BLR mass estimates in several existing textbooks suggest lower values, but pertain to much less luminous Seyfert galaxies or include only a small fraction of the ionized/emitting volume of the BLR. The previous estimates also fail to include the large amounts of BLR gas that emit at low efficiency (in a given line), but that must be present based on reverberation and other studies. Very highly ionized gas, as well as partially ionized and neutral gas lying behind the ionization zones, are likely additional sources of mass within the BLR. The high masses found here imply that the chemical enrichment of the BLR cannot be controlled by mass ejection from one or a few stars. A significant stellar population in the host galaxies must be contributing. Simple scaling arguments based on normal galactic chemical enrichment and solar or higher BLR metallicities show that the minimum mass of the enriching stellar population is of order 10 times the BLR mass, or greater than 10^4-10^5 M_sun. More realistic models of the chemical and dynamical evolution in galactic nuclei suggest that much larger, bulge-size stellar populations are involved., Comment: 12 pages, including 1 table and 2 figures. Accepted for publication in ApJ

We estimate the metallicity in the broad emission-line region of the redshift z=4.16 quasar, BR2248-1242, by comparing line ratios involving nitrogen to theoretical predictions. BR2248-1242 has unusually narrow emission lines with large equivalent widths, thus providing a rare opportunity to measure several line-ratio abundance diagnostics. The combined diagnostics indicate a metallicity of ~2 times solar. This result suggests that an episode of vigorous star formation occurred near BR2248-1242 prior to the observed z=4.16 epoch. The time available for this enrichment episode is only ~1.5 Gyr at z=4.16 (for H_{0}=65 km s^-1 Mpc^-1, Omega_{m}=0.3 and Omega_Lambda ~< 1). This evidence for high metallicities and rapid star formation is consistent with the expected early-epoch evolution of dense galactic nuclei., 8 pages, 3 figures. Prepared in AAStex. Submitted to the Astrophysical Journal Revised version: added 1 reference

We present results of a program of high signal-to-noise spectroscopy for 44 QSOs at redshifts > 4 using the MMT and Keck observatories. The quasar spectra cover 1100 -- 1700 A in the rest frame for sources spanning a luminosity range of approximately 2 orders of magnitude. Comparisons between these data and spectra of lower redshift quasars reveal a high degree of similarity, although differences are present in the profiles and the strengths of some emission features. An examination of the luminosity dependence of the emission lines reveals evidence for a weak or absent Baldwin effect among z > 4 QSOs. We compare measurements for objects in our sample with results from other high redshift surveys characterized by different selection techniques. Distributions of equivalent widths for these different ensembles are consistent with a common parent population, suggesting that our sample is not strongly biased, or in any case, subject to selection effects that are not significantly different from other surveys, including the Sloan Digital Sky Survey. Based on this comparison, we tentatively conclude that the trends identified here are representative of high z QSOs. In particular, the data bolster indications of supersolar metallicities in these luminous, high-z sources, which support scenarios that assume substantial star formation at epochs preceding or concurrent with the QSO phenomena., Comment: 26 pages (incl. 9 figures), AASTeX v5.0, to appear in The Astrophysical Journal

The broad emission lines (BELs) of quasars and active galactic nuclei (AGNs) are important diagnostics of the relative abundances and overall metallicity in the gas. Here we present new theoretical predictions for several UV BELs. We focus specifically on the relative nitrogen abundance as a metallicity indicator, based on the expected secondary enrichment of nitrogen at metallicities Z > 0.2 Z_o. Among the lines we consider, N III] 1750/O III] 1664, N V 1240/(C IV 1549 + O VI 1034) and N V/He II 1640 are the most robust diagnostics. We argue, in particular, that the average N V BEL is not dominated by scattered Ly-alpha photons from a broad absorption line wind. We then compare our calculated line ratios with observations from the literature. The results support earlier claims that the gas-phase metallicities near quasars are typically near or several times above the solar value. We conclude that quasar activity is preceded by, or coeval with, an episode of rapid and extensive star formation in the surrounding galactic (or proto-galactic) nuclei. Chemical evolution models of these environments suggest that, to reach Z > Z_o in well-mixed interstellar gas, the star formation must have begun > 10^8 yr before the observed quasar activity., 15 pages, 5 figures in 6 files, in press with ApJ. This version fixes some minor glitches and includes previously omitted references

We present Chandra observations of the radio-quiet broad absorption line (BAL) quasar PG 1254+047. We find that it is a weak X-ray source, with a total of 44 ± 7 photons measured in 36 ks across the observed energy range 0.7-6.0 keV. Its X-ray weakness is consistent with the known correlation between αox and the strength of the UV absorption lines. The spectral energy distribution suggests that PG 1254+047 is intrinsically X-ray weak, in addition to being heavily X-ray absorbed. The X-ray absorption column density is NH > 1023 cm-2 for neutral gas, while the intrinsic (unabsorbed) emission spectrum has αox > 2. The data are best fit by including an ionized (rather than neutral) absorber with column density NH 2 × 1023 cm-2. The degree of ionization is consistent with the UV BALs, as is the total column density if the strongest UV lines are saturated. If the X-ray absorber forms in a wind that is radiatively accelerated to the BAL velocities, then the wind must be launched from a radius of about 1016 cm with a mass-loss rate of ~1Q M☉ yr-1.

Associated absorption lines (AALs) are valuable probes of the gaseous environments near quasars. Here we discuss high-resolution (6.7 km/s) spectra of the AALs in the radio-loud quasar 3C 191 (redshift z=1.956). The measured AALs have ionizations ranging from Mg I to N V, and multi-component profiles that are blueshifted by ~400 to ~1400 km/s relative to the quasar's broad emission lines. These data yield the following new results. 1) The density based on Si II*/Si II lines is ~300 cm-3, implying a distance of ~28 kpc from the quasar if the gas is photoionized. 2) The characteristic flow time is thus \~3 x 10^7 yr. 3) Strong Mg I AALs identify neutral gas with very low ionization parameter and high density. We estimate n_H > 5 x 10^4 cm-3 in this region, compared to ~15 cm-3 where the N V lines form. 4) The total column density is N_H < 4 x 10^18 cm-2 in the neutral gas and N_H ~ 2 x 10^20 cm-2 in the moderately ionized regions. 5) The total mass in the AAL outflow is M ~ 2 x 10^9 Mo, assuming a global covering factor (as viewed from the quasar) of ~10% >. 6) The absorbing gas only partially covers the background light source(s) along our line(s) of sight, requiring absorption in small clouds or filaments, 15 pages text plus 6 figures, in press with ApJ

Infrared spectrophotometric observations from 0.8 to 2.5 μm are presented for the narrow-line, type 1 Seyfert galaxy I Zw 1. The data clearly reveal Fe II λ9997, λ10501, λ10863, and λ11126—the so-called "1 μm Fe II lines." These features are by far the strongest Fe II transitions in the entire 0.8-2.5 μm spectral region and, relative to the hydrogen lines, are equal or stronger in I Zw 1 than in any of the Galactic sources in which they have been detected previously. The 1 μm Fe II lines, which share a common upper term, are probably emitted by the broad line regions of many active galaxies but have escaped identification because of blending with nearby features of hydrogen and helium. A mechanism for their excitation through fluorescence by Lyα has been suggested previously in the literature, but the crucial cascade lines that feed the upper term in this process are not seen in I Zw 1. The low energy of the upper term indicates that the 1 μm Fe II lines are collisionally excited.

We discuss new Hubble Space Telescope spectroscopy of the radio-loud quasar, 3C 288.1. The data cover ~590 A to ~1610 A in the quasar rest frame. They reveal a wealth of associated absorption lines (AALs) with no accompanying Lyman-limit absorption. The metallic AALs range in ionization from C III and N III to Ne VIII and Mg X. We use these data and photoionization models to derive the following properties of the AAL gas: 1) There are multiple ionization zones within the AAL region, spanning a factor of at least ~50 in ionization parameter. 2) The overall ionization is consistent with the ``warm'' X-ray continuum absorbers measured in Seyfert 1 nuclei and other QSOs. However, 3) the column densities implied by the AALs in 3C 288.1 are too low to produce significant bound-free absorption at any UV-X-ray wavelengths. Substantial X-ray absorption would require yet another zone, having a much higher ionization or a much lower velocity dispersion than the main AAL region. 4) The total hydrogen column density in the AAL gas is log N_H (cm-2)= 20.2. 5) The metallicity is roughly half solar. 6) The AALs have deconvolved widths of ~900 km/s and their centroids are consistent with no shift from the quasar systemic velocity (conservatively within +/-1000 km/s). 7) There are no direct indicators of the absorber's location in our data, but the high ionization and high metallicity both suggest a close physical relationship to the quasar/host galaxy environment. Finally, the UV continuum shape gives no indication of a ``blue bump'' at higher energies. There is a distinct break of unknown origin at ~1030 A, and the decline toward higher energies (with spectral index alpha = -1.73, for f_nu ~ nu^alpha) is even steeper than a single power-law interpolation from 1030 A to soft X-rays.