Excess Galactic Molecular Absorption Toward the Radio Galaxy 3C 111

© 2017. The American Astronomical Society. All rights reserved. We show the combined spectral analysis of Chandra high-energy transmission grating and XMM-Newton reflection-grating spectrometer observations of the broad-line radio galaxy 3C 111. This source is known to show excess neutral absorption with respect to the one estimated from 21 cm radio surveys of atomic H i in the Galaxy. However, previous works were not able to constrain the origin of such an absorber as local to our Milky Way or intrinsic to the source (z = 0.0485). The high signal-to-noise grating spectra allow us to constrain the excess absorption as being due to intervening gas in the Milky Way, and we estimate a time-averaged total column density of NH = (7.4 ± 0.1) × 1021 cm-2, a factor of two higher than the tabulated H i value. We recommend using the total average Galactic column density estimated here when studying 3C 111. The origin of the extra Galactic absorption of NH = 4.4 × 1021 cm-2 is likely due to molecular gas associated with the Taurus molecular cloud complex toward 3C 111, which is our nearest star-forming region. We also detect a weak (EW = 16 ± 10 eV) and narrow (FWMH < 5500 km s-1, consistent with optical Hα) Fe Kα emission line at E = 6.4 keV, likely from the torus in the central regions of 3C 111, and we place an upper limit on the column density of a possible intrinsic warm absorber of N H < 2.5 ×1020 cm-2. These complexities make 3C 111 a very promising object for studying both the intrinsic properties of this active radio galaxy and the Galactic interstellar medium, if used as a background source

X-ray dips in the seyfert galaxy fairall 9: Compton-thick "cOMETS" or a failed radio galaxy?

We investigate the spectral variability of the Seyfert galaxy Fairall 9 using almost 6 years of monitoring with the Rossi X-ray Timing Explorer (RXTE) with an approximate time resolution of 4 days. We discover the existence of pronounced and sharp dips in the X-ray flux, with a rapid decline of the 2--20 keV flux of a factor 2 or more followed by a recovery to pre-dip fluxes after ~10 days . These dips skew the flux distribution away from the commonly observed log-normal distribution. Dips may result from the eclipse of the central X-ray source by broad line region (BLR) clouds, as has recently been found in NGC 1365 and Mrk 766. Unlike these other examples, however, the clouds in Fairall 9 would need to be Compton-thick, and the non-dip state is remarkably free of any absorption features. A particularly intriguing alternative is that the accretion disk is undergoing the same cycle of disruption/ejection as seen in the accretion disks of broad line radio galaxies (BLRGs) such as 3C120 but, for some reason, fails to create a relativistic jet. This suggests that a detailed comparison of Fairall 9 and 3C120 with future high-quality data may hold the key to understanding the formation of relativistic jets in AGN

THE COMPLEX CIRCUMNUCLEAR ENVIRONMENT of the BROAD-LINE RADIO GALAXY 3C 390.3 REVEALED by CHANDRA HETG

We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory. The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700–1000 eV associated with ionized Fe L transitions (Fe XVII–XX). An emission line at the energy of E sime 6.4 keV consistent with the Fe Kα is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 ± 0.1 keV; (ii) a warm absorber with ionization parameter logξ = 2.3 ± 0.5 erg s−1 cm, column density logN H = 20.7 ± 0.1 cm−2, and outflow velocity v out < 150 km s−1; and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei

Distant X-ray Galaxies: Insights from the Local Population

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 pres

Fundamental Strings, Holography, and Nonlinear Superconformal Algebras

We discuss aspects of holography in the AdS_3 \times S^p near string geometry of a collection of straight fundamental heterotic strings. We use anomalies and symmetries to determine general features of the dual CFT. The symmetries suggest the appearance of nonlinear superconformal algebras, and we show how these arise in the framework of holographic renormalization methods. The nonlinear algebras imply intricate formulas for the central charge, and we show that in the bulk these correspond to an infinite series of quantum gravity corrections. We also makes some comments on the worldsheet sigma-model for strings on AdS_3\times S^2, which is the holographic dual geometry of parallel heterotic strings in five dimensions.Comment: 25 page

The Imprint of Galaxy Formation on X-ray Clusters

It is widely believed that structure in the Universe evolves hierarchically, as primordial density fluctuations, amplified by gravity, collapse and merge to form progressively larger systems. The structure and evolution of X-ray clusters, however, seems at odds with this hierarchical scenario for structure formation. Poor clusters and groups, as well as most distant clusters detected to date, are substantially fainter than expected from the tight relations between luminosity, temperature and redshift predicted by these models. Here we show that these discrepancies arise because, near the centre, the entropy of the hot, diffuse intracluster medium (ICM) is higher tha$achievable through gravitational collapse, indicating substantial non-gravitational heating of the ICM. We estimate this excess entropy for the first time, and argue that it represents a relic of the energetic winds through which forming galaxies polluted the ICM with metals. Energetically, this is onl$ possible if the ICM is heated at modest redshift (z \ltsim 2) but prior to cluster collapse, indicating that the formation of galaxies precedes that of clusters and that most clusters have been assembled very recently.Comment: 5 pages, plus 2 postscript figures (one in colour), accepted for publication in Natur

Feeding and Feedback in the Powerful Radio Galaxy 3C 120

We present the spectral analysis of a 200~ks observation of the broad-line radio galaxy 3C~120 performed with the high energy transmission grating (HETG) spectrometer on board the \emph{Chandra} X-ray Observatory. We find (i) a neutral absorption component intrinsic to the source with column density of $\text{log}N_H = 20.67\pm0.05$~cm$^{-2}$, (ii) no evidence for a warm absorber with an upper limit on the column density of just $\text{log}N_H < 19.7$~cm$^{-2}$ assuming the typical ionization parameter log$\xi$$\simeq$2.5~erg~s$^{-1}$~cm, the warm absorber may instead be replaced by (iii) a hot emitting gas with temperature $kT \simeq 0.7$~keV observed as soft X-ray emission from ionized Fe L-shell lines which may originate from a kpc scale shocked bubble inflated by the AGN wind or jet with a shock velocity of about 1,000~km~s$^{-1}$ determined by the emission line width, (iv) a neutral Fe K$\alpha$ line and accompanying emission lines indicative of a Compton-thick cold reflector with low reflection fraction $R\simeq0.2$, suggesting a large opening angle of the torus, (v) a highly ionized Fe~XXV emission feature indicative of photoionized gas with ionization parameter log$\xi$$=$$3.75^{+0.27}_{-0.38}$~erg~s$^{-1}$~cm and a column density of $\text{log}N_H > 22$~cm$^{-2}$ localized within $\sim$2~pc from the X-ray source, and (vi) possible signatures for a highly ionized disk wind. Together with previous evidence for intense molecular line emission, these results indicate that 3C~120 is likely a late state merger undergoing strong AGN feedback.Comment: Accepted for publication in Ap

High Energy Neutrinos from Quasars

We review and clarify the assumptions of our basic model for neutrino production in the cores of quasars, as well as those modifications to the model subsequently made by other workers. We also present a revised estimate of the neutrino background flux and spectrum obtained using more recent empirical studies of quasars and their evolution. We compare our results with other thoeretical calculations and experimental upper limits on the AGN neutrino background flux. We also estimate possible neutrino fluxes from the jets of blazars detected recently by the EGRET experiment on the Compton Gamma Ray Observatory. We discuss the theoretical implications of these estimates.Comment: 14 pg., ps file (includes figures), To be published in Space Science Review

Breakdown of the adiabatic limit in low dimensional gapless systems

It is generally believed that a generic system can be reversibly transformed from one state into another by sufficiently slow change of parameters. A standard argument favoring this assertion is based on a possibility to expand the energy or the entropy of the system into the Taylor series in the ramp speed. Here we show that this argumentation is only valid in high enough dimensions and can break down in low-dimensional gapless systems. We identify three generic regimes of a system response to a slow ramp: (A) mean-field, (B) non-analytic, and (C) non-adiabatic. In the last regime the limits of the ramp speed going to zero and the system size going to infinity do not commute and the adiabatic process does not exist in the thermodynamic limit. We support our results by numerical simulations. Our findings can be relevant to condensed-matter, atomic physics, quantum computing, quantum optics, cosmology and others.Comment: 11 pages, 5 figures, to appear in Nature Physics (originally submitted version

BASS. XXXIV. A Catalog of the Nuclear Millimeter-wave Continuum Emission Properties of AGNs Constrained on Scales ≤ 100-200 pc

We present a catalog of the millimeter-wave (mm-wave) continuum properties of 98 nearby (z &lt; 0.05) active galactic nuclei (AGNs) selected from the 70 month Swift/BAT hard-X-ray catalog that have precisely determined X-ray spectral properties and subarcsecond-resolution Atacama Large Millimeter/submillimeter Array Band 6 (211-275 GHz) observations as of 2021 April. Due to the hard-X-ray (&gt;10 keV) selection, the sample is nearly unbiased for obscured systems at least up to Compton-thick-level obscuration, and provides the largest number of AGNs with high-physical-resolution mm-wave data (less than or similar to 100-200 pc). Our catalog reports emission peak coordinates, spectral indices, and peak fluxes and luminosities at 1.3 mm (230 GHz). Additionally, high-resolution mm-wave images are provided. Using the images and creating radial surface brightness profiles of mm-wave emission, we identify emission extending from the central sources and isolated blob-like emission. Flags indicating the presence of these emission features are tabulated. Among 90 AGNs with significant detections of nuclear emission, 37 AGNs (approximate to 41%) appear to have both or one of extended or blob-like components. We, in particular, investigate AGNs that show well-resolved mm-wave components and find that these seem to have a variety of origins (i.e., a jet, radio lobes, a secondary AGN, stellar clusters, a narrow-line region, galaxy disk, active star formation regions, or AGN-driven outflows), and some components have currently unclear origins