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Academic literature on the topic 'Quasar absorption lines'

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Published: 4 June 2021
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Journal articles on the topic "Quasar absorption lines"

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Harutyunian, Haik A. "Are There Quasars at Non-Cosmological Distances?" Symposium - International Astronomical Union 194 (1999): 428–31. http://dx.doi.org/10.1017/s0074180900162485.

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In Dravskikh & Dravskikh (1996) the results of a statistical analysis of quasar luminosity as a function of redshift, if it is assumed to be cosmological, are given (see Fig.1). Three quasar samples were analyzed separately: •quasars with absorption lines;•quasars associated with galaxies or association-quasars not having absorption lines (from Burbidge et al. 1996);•other quasars not included in the first two groups.
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Combes, F., N. Gupta, G. I. G. Jozsa, and E. Momjian. "Discovery of CO absorption at z = 0.05 in G0248+430." Astronomy & Astrophysics 623 (March 2019): A133. http://dx.doi.org/10.1051/0004-6361/201935057.

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Absorption lines in front of distant quasars are quite rare in the millimeter domain. They can, however, bring very useful and complementary information to emission lines. We report here the detection with NOEMA of CO(1–0) and CN(1–0) lines in absorption, and the confirmation of CO emission in the quasar/galaxy pair Q0248+430/G0248+430. The system G0248+430 corresponds to two merging galaxies (a Seyfert and a LINER) at z = 0.0519 with a tidal tail just on the line of sight to the background quasar Q0248+430 at z = 1.313. Optical (CaII, NaI), H I 21 cm, and OH-1667 MHz absorption lines associated with the tidal tail of the foreground system have previously been detected toward the quasar, while four CO lines at different rotation J levels have been detected in emission from the foreground galaxies. New H I 21 cm line observations with the upgraded GMRT array are also presented. We discuss the molecular content of the merging galaxies, and the physical conditions in the absorbing interstellar medium of the tidal tail.
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Aldcroft, T., J. Bechtold, P. Smith, C. Foltz, and G. Schmidt. "Optical Polarization and Line Variability in Quasars with Associated Absorption." International Astronomical Union Colloquium 163 (1997): 681–82. http://dx.doi.org/10.1017/s0252921100043396.

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AbstractThe physical origin of associated absorption lines (zabs ≈ zqso) which are observed in radio-loud quasar is generally not well understood. Two observable properties, line variability and quasar optical polarization, can serve to constrain the possibilities. To this end, we have obtained high-resolution spectra (1 Å) and broad-band optical polarizations for over 30 radio-loud quasars with known CIV associated absorption. The quasars are at redshifts between about 1 and 2, and were previously observed spectroscopically at similar resolution between 1985 – 1986 by Foltz et al (1987). The associated CIV absorption systems include a variety of velocity profiles from weak single lines to very complex multi-component systems to the BAL-like profile of PHL 1157+0128. In this poster we show the first strong evidence for line variability in z > 1 radio-loud quasars. We find that in general the variability is less than ~ 30%. The optical polarization of CIV absorbed quasars is consistent with all radio-loud quasars.
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Capellupo, Daniel M., Fred Hamann, Joseph C. Shields, Tom A. Barlow, and Paola Rodriguez. "Variability in Quasar Broad Absorption Line Outflows." Proceedings of the International Astronomical Union 5, S267 (August 2009): 394. http://dx.doi.org/10.1017/s1743921310006782.

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Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution (e.g., Di Matteo et al. 2005). Studying the variability in these BALs can help us understand the structure, evolution, and basic physical properties of these outflows. We are investigating BAL variability in a sample of 25 luminous quasars at 1.2 < z < 2.9 with multi-epoch observations that cover time scales from less than around a month to 7.7 years in the quasar rest-frame. We investigate changes in the C iv λ1549 BALs, and we see a variety of phenomena, including some BALs that either appeared or disappeared completely and other BALs that did not change at all over the whole observation period.
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Culliton, Chris, Jane Charlton, Mike Eracleous, Rajib Ganguly, and Toru Misawa. "Probing quasar winds using intrinsic narrow absorption lines." Monthly Notices of the Royal Astronomical Society 488, no. 4 (August 7, 2019): 4690–731. http://dx.doi.org/10.1093/mnras/stz1642.

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ABSTRACT We use the spectra of 73 quasars (1.5 ≲ z ≲ 5) from the VLT UVES archive to catalogue and study narrow absorption lines (NALs) that are physically associated with (intrinsic to) the quasars. We identify 410 NAL systems containing C iv, N v, and/or Si iv doublets. Based on the assumption that only systems intrinsic to the quasar can exhibit partial coverage of the background source(s), we identify 34 reliably intrinsic NAL systems and 11 systems that are potentially intrinsic, as well as 4 mini-broad absorption lines (BALs) and 1 BAL. The minimum fraction of quasars with at least one intrinsic system is shown to be 38 per cent. We identify intrinsic NALs with a wide range of properties, including apparent ejection velocity, coverage fraction, and ionization level. There is a continuous distribution of properties, rather than discrete families, ranging from partially covered C iv systems with black Ly α and with a separate low-ionization gas phase to partially covered N v systems with partially covered Ly α and without detected low-ionization gas. Even more highly ionized associated and intrinsic absorption systems (O vi, Ne viii, and Mg x doublets) have been presented in separate studies; these may represent an extension of the above sequence. We also use the properties of the NALs in conjunction with recent models of accretion disc winds that predict the origins of the absorbing gas in order to determine the model that best characterizes our sample. Additionally, we construct a model describing the spatial distributions, geometries, and varied ionization structures of intrinsic NALs.
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Sargent, Wallace L. W. "Quasar Absorption Lines: Evolution and Clustering." Symposium - International Astronomical Union 130 (1988): 333–42. http://dx.doi.org/10.1017/s0074180900136228.

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A large new sample of absorption redshifts derived from the C IV doublet in the spectra of 56 QSOs has been used to study the evolution and clustering tendencies of the heavy element absorbers (thought to be galaxies). The new data have been compared with more extensive existing data for the more common Lyman α forest lines (thought to be produced by intergalactic clouds). Little or no clustering is observed in the Lyman α forest lines; moreover, there is no evidence for voids in their distribution. Clustering has been detected in the heavy element redshifts on scales Δv ≥ 200 km s−1 where relative motions of clouds within galaxies are unlikely to dominate. The degree of clustering inferred at z ≈ 2 is of the order expected on the simplest model for the evolution of galaxy clustering in cosmic time. The recent discovery of similar concentrations of absorption features extending over Δz ∼ 0.2 in the spectra of widely separated QSOs on the sky provides evidence for very large structures, probably filaments or sheets of galaxies, extending over 100 Mpc (co-moving). The Lyman α forest and heavy element redshifts evolve very differently. The Lyman lines show a rapid increase in density with increasing z, while the C IV doublets show a decrease. This result emphasizes that there are two discrete populations of absorbers. The decrease in C IV line density may be due to the effects of the onset of stellar nucleosynthesis in galaxies.
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Bechtold, Jill. "Evolution of the EUV Background from Quasar Absorption Line Studies." Symposium - International Astronomical Union 168 (1996): 237–44. http://dx.doi.org/10.1017/s0074180900110125.

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The integrated extreme ultraviolet (EUV) radiation from quasars and other high redshift sources provides an ambient ionizing radiation field which may photoionize the gas seen as quasar absorption lines. In particular, the observed evolution of the Lyα forest clouds probably results in part from the evolution of the EUV metagalactic field. Estimates of the EUV field as a function of redshift can be made from measuring the “proximity effect” in quasar spectra; uncertainties in these estimates may be large. Given the uncertainties, the estimated EUV field at z≈3 derived from the proximity effect is in reasonable agreement with the expected contribution from luminous quasars.
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Richards, Gordon T., S. A. Laurent‐Muehleisen, Robert H. Becker, and Donald G. York. "Quasar Absorption Lines as a Function of Quasar Orientation Measures." Astrophysical Journal 547, no. 2 (February 2001): 635–48. http://dx.doi.org/10.1086/318414.

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Lu, Wei-Jian, and Ying-Ru Lin. "Velocity shift of Mg ii and Al iii broad absorption lines in quasar SDSS J134444.33+315007.6." Monthly Notices of the Royal Astronomical Society: Letters 499, no. 1 (September 23, 2020): L58—L61. http://dx.doi.org/10.1093/mnrasl/slaa158.

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ABSTRACT We report, for the first time, a synchronized velocity shift of Mg ii and Al iii broad absorption lines (BALs) in quasar SDSS J134444.33+315007.6 (hereafter, J1344+3150). We found this quasar from a sample of 134 Mg ii BAL quasars with multi-epoch observations. This quasar contains three low-ionization BAL systems, the fastest of which at ${\sim} -17\, 000\, \rm km\, s^{-1}$ shows a kinematic shift of ${\sim} -1101$ and $\sim -1170\, \rm km\, s^{-1}$ in its Mg ii and Al iii ions, respectively, during a rest-frame time of about 3.21 yr. Meanwhile, this quasar also shows other various variation characteristics, including an obvious weakening in its continuum, a coordinated enhancement in multiple emission lines (Mg ii, C iii, and Al iii), and a coordinated enhancement in three Al iii absorption troughs. These variation characteristics convincingly indicate that the BAL outflows of J1344+3150 are under the influence from the background radiation energy. Thus, we infer that the velocity shift displayed in system A in the quasar J1344+3150 may indicate an actual line-of-sight acceleration of an outflow due to the radiation pressure from the central source.
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Chartas, George, and Sarah Strickland. "Wide-Angle Quasar Feedback." Proceedings of the International Astronomical Union 11, S319 (August 2015): 58. http://dx.doi.org/10.1017/s1743921315010145.

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AbstractWe present results from the detection of relativistic winds launched near the innermost stable circular orbits of supermassive black holes. A recent detection of a powerful wind in the X-ray-bright narrow absorption line (NAL) z=1.51 quasar HS 0810+2554 strengthens the case that quasars play a significant role in feedback. In both deep Chandra and XMM-Newton observations of HS 0810 we detected blueshifted absorption lines implying outflowing velocities ranging from 0.1c and 0.4c. The presence of both an emission line at 6.8 keV and an absorption line at 7.8 keV in the spectral line profile of HS 0810 is a characteristic feature of a P-Cygni profile supporting the presence of an expanding outflowing highly ionized Fe absorber. A hard excess component is detected in the XMM-Newton observation of HS 0810 possibly originating from reflection off the disk. Modelling of the XMM-Newton spectrum constrains the inclination angle to be < 35° (68% confidence). The presence of relativistic winds in both low inclination angle NAL quasars as well as in high inclination angle BAL quasars implies that the solid angle of quasar winds may be quite large. The larger solid angle of quasar winds would also indicate that their contribution to the regulation of the host galaxy may be more important than previously thought.
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Dissertations / Theses on the topic "Quasar absorption lines"

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Crighton, Neil Physics Faculty of Science UNSW. "Cosmology with Quasar Absorption Lines." Awarded by:University of New South Wales. Physics, 2006. http://handle.unsw.edu.au/1959.4/30178.

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In this thesis we make a new measurement of the primordial deuterium abundance, and analyse five other systems selected as possible D/H candidates. We also undertake an investigation of systematic errors in a system where an existing deuterium measurement has been made. We measure the number of hydrogen components and their velocity distributions in a moderate and high redshift sample of Lyman limit systems in one Angstrom resolution spectra. We present a new measurement of the deuterium-to-hydrogen ratio, D/H, at z=3.2560 in a newly-discovered low metallicity absorption system towards the quasar PG1937-1009. We attempt to account for any systematic effects that could influence the D/H measurement. We find a 1 sigma range for D/H*1e5 of 1.6 (+0.25) (-0.30). Using high resolution spectra from the Hubble Space Telescope and the Very Large Telescope, we assess the suitability of five D/H candidate absorption systems. These systems were selected as candidates using lower resolution spectra. We measure the neutral hydrogen column density, identify metal lines and analyse the velocity structure of each system, and show them to be unsuitable for measuring D/H. We also investigate the systematic errors in the absorber at z=0.701 towards quasar PG1718-4801 that was initially thought to show a high primordial D/H value. We analyse the dependence of the putative deuterium line's parameters on wavelength calibration errors in the HST spectra and present a revised deuterium measurement. We examine the velocity widths of two samples of one Angstrom resolution quasar spectra showing Lyman limit absorption systems. The first sample is at high redshifts, taken from the Sloan quasar data release 3 catalogue. The second is at intermediate redshifts, compiled from a survey for UV quasar absorption systems taken with the Hubble Space Telescope. We use a modified version of the Voigt profile fitting program, VPFIT, to estimate the number of hydrogen velocity components and column density in the Lyman limit systems. We compare the velocity distributions of the higher and lower redshift samples. We find the distributions are consistent with other measures of the velocity spread in absorption systems, and find no compelling evidence for evolution between the redshift samples.
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Webb, J. K. "QSO absorption lines." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234000.

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The absorption lines found in the spectra of distant quasars provide a unique method of probing the physical conditions in the universe at early epochs. This thesis describes a study of the Lyman alpha forest absorption systems seen in the spectra of high redshift QSOs. The Anglo-Australian Telescope has been used to obtain high resolution spectra of several bright QSOs. Considerable effort has gone into developing statistical techniques for profile fitting to the data to objectively and reliably extract the parameters associated with each absorbing cloud. The distribution functions for these are given and discussed. Particular attention has been paid to the clustering properties of the Lyman alpha clouds and it is found that they are weakly (but significantly) clustered on small velocity scales. Possible interpretations of this result are discussed. One especially interesting aspect of QSO absorption systems concerns the potential for measuring, or obtaining limits on, the deuterium to hydrogen abundance at high redshifts. A knowledge of this quantity is important for constraining cosmological models and can also help us to understand the chemical evolution of light elements in galaxies. A series of numerical simulations has been carried out to explore the potential for such measurements and an absorption system has been analysed to obtain an upper limit to D/H at z = 3.
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Murphy, Michael T. Physics Faculty of Science UNSW. "Probing variations in the fundamental constants with quasar absorption lines." Awarded by:University of New South Wales. School of Physics, 2002. http://handle.unsw.edu.au/1959.4/19062.

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Precision cosmology challenges many aspects of fundamental physics. In particular, quasar absorption lines test the assumed constancy of fundamental constants over cosmological time-scales and distances. Until recently, the most reliable technique was the alkali doublet (AD) method where the measured doublet separation probes variations in the fine-structure constant, ???? e2/??c. However, the recently introduced many-multiplet (MM) method provides several advantages, including a demonstrated ???10-fold precision gain. This thesis presents detailed MM analyses of 3 independent Keck/HIRES samples containing 128 absorption systems with 0.2 > zabs > 3.7. We find 5.6 ?? statistical evidence for a smaller ?? in the absorption clouds: ????/?? = (-0.574 ?? 0.102) x 10-5. All three samples separately yield consistent, significant ????/??. The data marginally prefer constant d??/dt rather than constant ????/??. The two-point correlation function for ?? and the angular distribution of ????/?? give no evidence for spatial variations. We also analyse 21 Keck/HIRES Si iv doublets, obtaining a 3-fold relative precision gain over previous AD studies: ????/?? = (-0.5 ?? 1.3) x 10-5 for 2.0 > zabs > 3.1. Our statistical evidence for varying ?? requires careful consideration of systematic errors. Modelling demonstrates that atmospheric dispersion is potentially important. However, the quasar spectra suggest a negligible effect on ????/??. Cosmological variation in Mg isotopic abundances may affect ????/?? at zabs > 1.8. Galactic observations and theory suggest diminished 25;26Mg abundances in the low metallicity quasar absorbers. Removing 25;26Mg isotopes yields more negative ????/?? values. Overall, known systematic errors can not explain our results. We also constrain variations in y ?? ?? 2gp, comparing H i 21-cm and millimetrewave molecular absorption in 2 systems. Fitting both the H i and molecular lines yields the tightest, most reliable current constraints: ??y/y = (-0.20??0.44)x10-5 and (-0.16??0.54)x10-5 at zabs = 0.2467 and 0.6847 respectively. Possible line-ofsight velocity differences between the H i and molecular absorbing regions dominate these 1 ?? errors. A larger sample of mm/H i comparisons is required to reliably quantify this uncertainty and provide a potentially crucial check on the MM result.
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BECHTOLD, JILL ELEANOR. "HIGH RESOLUTION SPECTROSCOPY OF QUASAR ABSORPTION LINES (INTERGALACTIC MEDIUM, EXTRAGALACTIC, GALAXIES)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188085.

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This dissertation investigates the properties of the metal-containing absorption lines seen in quasar spectra which have Z(abs) < < Z(em). These systems, which probably originate in the halos of galaxies at high redshift, are then compared to observations of the halo and interstellar medium of the Milky Way. We obtained echelle spectra at the Multiple Mirror Telescope (MMT) of the Z = 1.79 absorption system of the quasar B2 1225+317. The velocity profiles showed complex structure which varied from ion to ion, with ionization and column densities varying from component to component. The relative colums were consistent with the expectations for approximately interstellar abundance, low density material, in equilibrium with the ultraviolet radiation field of a spiral galaxy for λ > 912 A, and the integrated light from QSOs at Z = 1.79 for λ < 912 A. The aggregate C IV profile has a width of about 450 km/sec, larger than that expected for a single galaxy halo, however. With the MMT spectrograph and echellette grating, and MMT echelle, we studied the properties of three other redshift systems of B2 1225+317, which are optically thin at the Lyman limit, but have saturated Lyman alpha, and unlike material in the Milky Way, have strong C IV and no detectable C II. In some cases Si III and Si IV are weakly detected. Constructing photoionization models, we derive low total densities, cloud diameters on the order of a few kiloparsecs, and abundances which are consistent with the interstellar values. We calculated the contribution of quasars to the UV radiation field as a function of redshift. The calculated field depends on a number of uncertain assumptions, which were varied in order to estimate their effect on the result. Finally, we discuss an important input into these calculations, the continuum spectral energy distribution for quasars, with particular attention to the extreme ultraviolet.
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Morrison, Sean Stephen. "Using quasar absorption to study inhomogeneities in the UV background." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0501.

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L'étude du fond UV (UVB) est importante pour comprendre l'évolution de l'Univers. Le UVB évolue et est inhomogène. Cette thèse se concentre sur l'étude des inhomogénéités à grande échelle dans le UVB extragalactique, et les modifications des métaux du fait de proximité des quasars. Nous commençons par explorer les échelles dominante de ces inhomogénéités dans le UVB en combinant l'absorption intergalactique par l'hydrogène, l'hélium (HeII) et l'oxygène dans les lignes de visée du 2 quasars. Elle a révélé des inhomogénéités sur des échelles de ~10cMpc et \gtrsim 200cMpc à \bar{z}\approx 2.6. Cette analyse a également été appliquée au «HeII Gunn-Peterson trough» et n'a montré aucun signe de réionisation de HeII par rapport aux données de la «forêt» de HeII. Nous poursuivons par l'exploration de la relation directe entre les quasars et l'ionisation des métaux, en regroupant les absorbeurs de l'IGM par proximité aux quasars les plus proches dans SDSS eBOSS. Bien qu’une tendance à une absorption plus faible par des espèces caracterisées par l’ionisation élevée et par une plus grande séparation soit observée, les échantillons actuels des quasars sont incomplets, limitent donc l'interprétation détaillée de ces resultats. Cependant, nous démontrons que la contribution des quasars à le UVB peut être explorée à l'aide des métaux IGM. Finalement, nous discutons ma contribution pour atteindre échantillon complet de quasar, à l'effort de validation des outils de réduction WEAVE, ainsi qu'à la compréhension de la population des quasars et de la qualité spectrale attendues pour cet sondage. Nous terminons par un évaluation de l'impact potentiel de cet échantillon sur notre analyse
The study of the background radiation in the UV band is important for understanding the evolution of the Universe. The UV background (UVB) evolves and is inhomogeneous. It arises by virtue of quasars and star-forming galaxies, modifies the matter of the Universe by ionizing and heating gas. The focus of this thesis is the study of large-scale inhomogeneities in the extragalactic UVB and the modifications of metals by quasar proximity. We begin with the exploration of the dominant scales of inhomogeneities in the UVB by combining intergalactic absorption by hydrogen, helium (HeII), and oxygen in 2 quasar lines-of-sight. This combination was studied on various filtering scales and by comparing the lines-of-sight. It revealed inhomogeneities on scales of ~10cMpc and \gtrsim 200cMpc at \bar{z}\approx 2.6. This analysis was also applied to the HeII Gunn-Peterson trough, which showed no evidence of HeII reionization when compared to HeII forest data. We continue with an exploration of the direct relationship of quasars and metal ionization, by grouping intergalactic medium (IGM) absorbers by their proximity to their closest quasars in SDSS-IV/eBOSS. While this shows sensitivity to large-scale 3D quasar proximity, the current incomplete quasar samples limit detailed interpretation. It does demonstrate that the quasar contribution to the UVB can be explored by examining the metal absorption in the IGM. Finally, we discuss my contributions towards a complete quasar sample through validating the WEAVE reduction pipeline, as well assessing the expected quasar population and spectral quality. We close by discussing the potential impact of this sample on our analysis
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Pieri, Matthew Michael. "Probing the metal enrichment of the intergalactic medium with quasar absorption lines." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416065.

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Zou, Siwei. "Using quasar absorption lines to probe cold gas in high redshift galaxies." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS181/document.

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Les raies d'absorption de quasars sont des outils efficaces pour étudier le milieu interstellaire dans les galaxies. Dans ce travail, nous étudions un échantillon de soixante-six systèmes absorbants à z<1.5 sélectionnés pour la présence de raies d'absorption de CI intenses dans leurs spectres SDSS. Ils sont observés par les spectrographes X-shooter et UVES du VLT de l'ESO. Nous étudions en tout 17 systèmes observés par X-shooter. Nous déduisons la métallicité, la déplétion par la poussière, le taux d'extinction par la poussière et le taux d'absorption des raies de MgII, MgI, CaII et NaI décalées dans l'infrarouge proche. Nous détectons neuf raies d'absorption de CaII avec W(CaII λ3934)>0.23Å. Nous détectons dix raies d'absorption de NaI dans quatorze systèmes susceptibles d'en montrer. La largeur équivalente médiane de W(NaI λ5891)=0.68Å est plus grande que celles observées dans des nuages proches ayant des densités-colonnes de HI similaires ou dans des systèmes CaII à z<0.7 détectés par le SDSS. La présence systématique de raies d'absorption de NaI dans ces systèmes CI suggère fortement que le gaz environnant est neutre et froid, et donc peut faire partie du gaz moléculaire diffus dans le milieu interstellaire de galaxies à fort décalage vers le rouge. Les raies d'absorption de MgII s'étalent sur plus de 400km/s en Δv pour la moitié de l'échantillon; trois systèmes ont un Δv supérieur à 500 km/s. Tout ceci suggère qu'une fraction importante du gaz froid à fort décalage vers le rouge émane d'environnements perturbés. Nous détectons de l'hydrogène moléculaire dans tous les systèmes dans la limite de détection
Quasar absorption lines are a powerful tool to study the interstellar medium(ISM) in the galaxies. We study a sample of 66 z >1.5 absorbers selected based on the presence of strong CI absorption lines in SDSS spectra and observed with the ESO-VLT spectrograph X-shooter/UVES. I study 17 systems that are re-observed by X-shooter. I derive metallicities, depletion onto dust, extinction by dust and analyse the absorption from MgII, MgI, CaII and NaI that are redshifted into the near infrared wavelength range. I detect 9 CaII absorptions with W(CaII λ3934) > 0.23 Å out of 14 systems. I detect 10 NaI absorptions in the 11 systems where we could observe this absorption. The median equivalent width (W(NaI λ5891) = 0.68 Å) is larger than what is observed in local clouds with similar HI column densities but also in z<0.7 CaII systems detected in the SDSS. The systematic presence of NaI absorption in these CI systems strongly suggests that the gas is neutral and cold, maybe part of the diffuse molecular gas in the ISM of high-redshift galaxies. The MgII absorptions are spread over more than Δv ~ 400 km/s for half of the systems; three absorbers have Δv > 500 km/s. The kinematics is strongly perturbed for most of these systems which probably do not arise in quiet disks and must be close to regions with intense star formation activity. All this suggests that a large fraction of the cold gas at high redshift arises in disturbed environments. We detect molecular hydrogen in all the systems within the detection limit
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Xu, Xinfeng. "How Do Quasars Impact Their Host Galaxies? From the Studies of Quasar Outflows in Absorption and Emission." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/98572.

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``Quasar-mode feedback'' occurs when momentum and energy from the environment of accreting supermassive black hole couple to the host galaxy. One mechanism for such a coupling is by high-velocity (up to $sim$ 0.2c) quasar-driven ionized outflows, appearing as blue-shifted absorption and emission lines in quasar spectra. Given enough energy and momentum, these outflows are capable of affecting the evolution of their host galaxies. This dissertation presents the studies of emission and absorption quasar outflows from different perspectives. (1). By conducting large broad absorption line (BAL) quasar surveys in both Sloan Digital Sky Survey and Very Large Telescopes (VLT), we determined various physics properties of quasar absorption outflows, e.g., the electron number density (ne), the distance of outflows to the central quasar ($R$), and the kinetic energy carried by the outflow ($dot{E}_{k}$). We demonstrated that half of the typical BAL outflows are situated at $R$ $>$ 100 pc, i.e., having the potential to affect the host galaxies. (2). Our group carried out a Hubble Space Telescope program (PI: Arav) for studying the outflows in the Extreme-UV, collaborating with Dr. Gerard Kriss from Space Telescope Science Institute (STScI). We developed a novel method to fit the multitude of quasar absorption troughs efficiently and accurately. We have identified the most energetic quasar-driven outflows on record and discovered the largest acceleration and velocity-shift for a quasar absorption outflow. (3). By using the VLT data, Xu led the project to study the relationships between BAL outflows and emission line outflows. We found possible connections between these two types of quasar outflows, e.g., the luminosity of the [oiii] ly 5007 emission profile decreases with increasing ne derived from the BAL outflow in the same quasar. These findings are consistent with BAL and emission outflows being different manifestations of the same wind, and the observed relationships are likely a reflection of the outflow density distribution.
Doctor of Philosophy
Super massive black holes (SMBHs) are believed to exist in the center of almost all massive galaxies, where the brightest accreting ones are named ``quasars''. ``Quasar-mode feedback'' occurs when momentum and energy from the environment of accreting SMBHs couple to the host galaxy. One mechanism for such a coupling is by high-velocity (up to $sim$ 0.2c) quasar-driven ionized outflows, appearing as blue-shifted absorption and emission lines in quasar spectra. Given enough energy and momentum, these outflows are capable of affecting the evolution of their host galaxies. Such quasar outflows are invoked to explain a variety of observations, e.g., the chemical enrichment of the intergalactic medium (IGM), the shape of the observed quasar luminosity function, and the self-regulation of the growth of the SMBHs. In this dissertation, I focus on studying the emission and absorption outflows observed in quasars spectra, collected with the largest telescopes and most powerful instruments in the world. (1). By conducting large broad absorption line (BAL) quasar surveys in both Sloan Digital Sky Survey and Very Large Telescopes (VLT), we determined various physics properties of quasar absorption outflows, e.g., the electron number density (ne), the distance of outflows to the central quasar ($R$), and the kinetic energy carried by the outflow ($dot{E}_{k}$). We demonstrated that half of the typical BAL outflows are situated at $R$ $>$ 100 pc, i.e., having the potential to affect the host galaxies. (2). Our group carried out a Hubble Space Telescope program (PI: Arav) for studying the outflows in the Extreme-UV, collaborating with Dr. Gerard Kriss from Space Telescope Science Institute (STScI). We developed a novel method to fit the multitude of quasar absorption troughs efficiently and accurately. We have identified the most energetic quasar-driven outflows on record and discovered the largest acceleration and velocity-shift for a quasar absorption outflow. (3). By using the VLT data, Xu led the project to study the relationships between BAL outflows and emission line outflows. We found possible connections between these two types of quasar outflows, e.g., the luminosity of the [oiii] ly 5007 emission profile decreases with increasing ne derived from the BAL outflow in the same quasar. These findings are consistent with BAL and emission outflows being different manifestations of the same wind, and the observed relationships are likely a reflection of the outflow density distribution.
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Krogager, J. K., J. P. U. Fynbo, K. E. Heintz, S. Geier, C. Ledoux, P. Møller, P. Noterdaeme, B. P. Venemans, and M. Vestergaard. "THE EXTENDED HIGH A(V) QUASAR SURVEY: SEARCHING FOR DUSTY ABSORBERS TOWARD MID-INFRARED-SELECTED QUASARS." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/624064.

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We present the results of a new spectroscopic survey for dusty intervening absorption systems, particularly damped Ly alpha absorbers (DLAs), toward reddened quasars. The candidate quasars are selected from mid-infrared photometry from the Wide-field Infrared Survey Explorer combined with optical and near-infrared photometry. Out of 1073 candidates, we secure low-resolution spectra for 108 using the Nordic Optical Telescope on La Palma, Spain. Based on the spectra, we are able to classify 100 of the 108 targets as quasars. A large fraction (50%) is observed to have broad absorption lines (BALs). Moreover, we find six quasars with strange breaks in their spectra, which are not consistent with regular dust reddening. Using template fitting, we infer the amount of reddening along each line of sight ranging from A(V). approximate to. 0.1 to 1.2 mag (assuming a Small Magellanic Cloud extinction curve). In four cases, the reddening is consistent with dust exhibiting the 2175 angstrom feature caused by an intervening absorber, and for two of these, an Mg II absorption system is observed at the best-fit absorption redshift. In the rest of the cases, the reddening is most likely intrinsic to the quasar. We observe no evidence for dusty DLAs in this survey. However, the large fraction of BAL quasars hampers the detection of absorption systems. Out of the 50 non-BAL quasars, only 28 have sufficiently high redshift to detect Ly alpha in absorption.
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10

Liu, Wen-Juan, Hong-Yan Zhou, Ning Jiang, Xufen Wu, Jianwei Lyu, Xiheng Shi, Xinwen Shu, et al. "SDSS J163459.82+204936.0: A RINGED INFRARED-LUMINOUS QUASAR WITH OUTFLOWS IN BOTH ABSORPTION AND EMISSION LINES." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621240.

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SDSS J163459.82+204936.0 is a local (z = 0.1293) infrared-luminous quasar with L-IR = 10(11.91) L-circle dot. We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy, appearing as an early-type galaxy in the optical images and spectra, demonstrates violent, obscured star formation activities with SFR approximate to 140 M-circle dot yr(-1), estimated from either the polycyclic aromatic hydrocarbon emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in H beta, He I lambda lambda 5876, 10830, and other emission lines consistently with an offset velocity of approximate to 900 km s(-1), as well as additional blueshifting phenomena in high-ionization lines (e.g., a blueshifted broad component of He I lambda 10830 and the bulk blueshifting of [O III].5007), while there exist blueshifted broad absorption lines (BALs) in Na I. D and He I lambda lambda 3889, 10830, indicative of the active galactic nucleus outflows producing BALs and emission lines. Constrained mutually by the several BALs in the photoionization simulations with Cloudy, the physical properties of the absorption line outflow are derived as follows: density 10(4) < n(H) less than or similar to 10(5) cm(-3), ionization parameter 10(-1.3) less than or similar to U 10(-0.7), and column density 10(22.5) less than or similar to N-H less than or similar to 10(22.9) cm(-2), which are similar to those derived for the emission line outflows. This similarity suggests a common origin. Taking advantages of both the absorption lines and outflowing emission lines, we find that the outflow gas is located at a distance of similar to 48-65 pc from the nucleus and that the kinetic luminosity of the outflow is 10(44)-10(46) erg s(-1). J1634+2049 has a off-centered galactic ring on the scale of similar to 30. kpc that is proved to be formed by a recent head-on collision by a nearby galaxy for which we spectroscopically measure the redshift. Thus, this quasar is a valuable object in the transitional phase emerging out of dust enshrouding as depicted by the coevolution scenario invoking galaxy merger (or violent interaction) and quasar feedback. Its proximity enables our further observational investigations in detail (or tests) of the co-evolution paradigm.
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Books on the topic "Quasar absorption lines"

1

Colloquium, International Astronomical Union. Probing galaxies through quasar absorption lines: Proceedings of the 199th colloquium of the International Astronomical Union held in Shanghai, People's Republic of China, March 14-18, 2005. Cambridge: Cambridge University Press, 2005.

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Chris, Blades J., Turnshek David Alvin, Norman Colin A, and Space Telescope Science Institute (U.S.), eds. QSO absorption lines: Probing the universe : proceedings of the QSO Absorption Line Meeting, Baltimore, 1987, May 19-21. Cambridge: Cambridge University Press, 1988.

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Quasar Absorption Lines. Cambridge University Press, 2008.

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(Editor), Peter Williams, Cheng-Gang Shu (Editor), and Brice Menard (Editor), eds. Probing Galaxies through Quasar Absorption Lines (IAU C199) (Proceedings of the International Astronomical Union Symposia and Colloquia). Cambridge University Press, 2005.

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QSO Absorption Lines: Probing the Universe (Space Telescope Science Institute Symposium Series). Cambridge University Press, 1988.

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G, Meylan, and European Southern Observatory, eds. QSO absorption lines: Proceedings of the ESO workshop held at Garching, Germany, 21-24 November 1994. Berlin: Springer, 1995.

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European Southern Observatory (Corporate Author) and Georges Meylan (Editor), eds. Qso Absorption Lines: Proceedings of the Eso Workshop Held at Garching, Germany, 21-24 November 1994 (Eso Astrophysics Symposia). Springer, 1995.

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Radiation pressure-driven magnetic disk winds in broad absorption line quasi-stellar objects. [Washington, DC: National Aeronautics and Space Administration, 1995.

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C, Begelman Mitchell, and United States. National Aeronautics and Space Administration., eds. Radiation pressure-driven magnetic disk winds in broad absorption line quasi-stellar objects. [Washington, DC: National Aeronautics and Space Administration, 1995.

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Radiation pressure-driven magnetic disk winds in broad absorption line quasi-stellar objects. [Washington, DC: National Aeronautics and Space Administration, 1995.

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Book chapters on the topic "Quasar absorption lines"

1

Smette, Alain. "Gravitational Lenses and Quasar Absorption Lines." In QSO Absorption Lines, 275–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_56.

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Dinshaw, N., C. D. Impey, C. B. Foltz, R. J. Weymann, and F. H. Chaffee. "Common Lyα Absorption Toward the Quasar Pair Q1343+2640A,B." In QSO Absorption Lines, 329–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_65.

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de la Fuente, A., Rodríguez-Pascual, J. L. Sanz, M. C. Recondo, J. Clavel, M. Santos-Lleó, and W. Wamsteker. "High-Resolution Spectroscopy of the Bright Quasar HS 1946+7658." In QSO Absorption Lines, 333–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_67.

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Bergvall, N., G. Östlin, K. G. Karlsson, E. Örndahl, and J. Rönnback. "Limits on Star Formation Rates in Four Quasar Metal-Line Absorbers." In QSO Absorption Lines, 205–6. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_42.

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Bergeron, Jacqueline, Blair Savage, and Richard F. Green. "Quasar Absorption Lines and Galaxy Halos." In Astrophysics and Space Science Library, 703–25. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3753-6_33.

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Sargent, Wallace L. W. "Quasar Absorption Lines: Evolution and Clustering." In Large Scale Structures of the Universe, 333–42. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2995-1_47.

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Boksenberg, Alec. "Observations of Lyman-α and Lyman-Limit Systems from the HST Quasar Absorption Line Key Project." In QSO Absorption Lines, 253–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_53.

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Dinshaw, N., C. B. Foltz, C. D. Impey, R. J. Weymann, and S. L. Morris. "Evidence for Large, Quiescent Lyman-Alpha Clouds from HST UV Spectroscopy of the Quasar Pair Q0107-025A,B." In QSO Absorption Lines, 323–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49458-4_63.

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Müller, V., J. P. Mücket, H. J. Haubold, and S. Gottlöber. "Analysis of Absorption Lines in Quasar Spectra." In Data Analysis in Astronomy III, 179–85. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-5646-2_20.

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Crotts, Arlin P. S. "Quasar Absorption Lines and High Redshift Galaxies." In Astrophysics and Space Science Library, 305–11. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2919-7_36.

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Conference papers on the topic "Quasar absorption lines"

1

Misawa, Toru. "Time-Variable Complex Metal Absorption Lines in the Quasar HS1603+3820." In ORIGIN OF MATTER AND EVOLUTION OF GALAXIES: International Symposium on Origin of Matter and Evolution of Galaxies 2005: New Horizon of Nuclear Astrophysics and Cosmology. AIP, 2006. http://dx.doi.org/10.1063/1.2234449.

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Chartas, George, Luka Č Popović, and Milan S. Dimitrijević. "X-ray Absorption Line Diagnostics of Quasar Outflows." In SPECTRAL LINE SHAPES IN ASTROPHYSICS: VI Serbi an Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA). AIP, 2007. http://dx.doi.org/10.1063/1.2800150.

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Scaringi, Simone, Christopher E. Cottis, Christian Knigge, Michael R. Goad, and Coryn A. L. Bailer-Jones. "Broad Absorption Line Quasar catalogues with Supervised Neural Networks." In CLASSIFICATION AND DISCOVERY IN LARGE ASTRONOMICAL SURVEYS: Proceedings of the International Conference: “Classification and Discovery in Large Astronomical Surveys”. AIP, 2008. http://dx.doi.org/10.1063/1.3059042.

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Danezis, E., E. Lyratzi, L. Č Popović, M. S. Dimitrijević, A. Antoniou, Marco Antonio Gigosos, and Manuel Ángel González. "Similarity Between DACs∕SACs Phenomena in Hot Emission Stars and Quasars Absorption Lines." In SPECTRAL LINE SHAPES: Volume 15–19th International Conference on Spectral Line Shapes. AIP, 2008. http://dx.doi.org/10.1063/1.3026466.

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Gawronski, Marcin. "High resolution studies of Broad Absorption Lines radio-loud quasars." In 10th European VLBI Network Symposium and EVN Users Meeting: VLBI and the new generation of radio arrays. Trieste, Italy: Sissa Medialab, 2011. http://dx.doi.org/10.22323/1.125.0037.

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Ceglowski, M., Magdalena Kunert-Bajraszewska, B. Pazderska, and Marcin Gawronski. "30 GHz monitoring of broad absorption line (BAL) quasars." In 11th European VLBI Network Symposium & Users Meeting. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.178.0080.

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Storrie-Lombardi, Lisa J. "Quasar absorption line studies of galaxies and the intergalactic medium at." In AFTER THE DARK AGES. ASCE, 1999. http://dx.doi.org/10.1063/1.58638.

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Bruni, Gabriele. "Morphology and orientation of radio-loud Broad Absorption Line quasars." In 10th European VLBI Network Symposium and EVN Users Meeting: VLBI and the new generation of radio arrays. Trieste, Italy: Sissa Medialab, 2011. http://dx.doi.org/10.22323/1.125.0036.

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Kunert-Bajraszewska, Magdalena. "Broad absorption line (BAL) quasars as a class of low luminosity AGNs." In 12th European VLBI Network Symposium and Users Meeting. Trieste, Italy: Sissa Medialab, 2015. http://dx.doi.org/10.22323/1.230.0008.

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Xie, Ruikang, Jianmin Li, and Yan Chen. "The Graded Origami Structures." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46081.

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There are many excellent graded structures existing in nature to optimize the mechanical properties in various load situations by adjusting the distribution of materials. In this research, rigid origami and graded structure concept are combined together to form the graded origami structures. Seven methods are proposed, including changing the length of crease lines, changing the sector angle, changing the number of units, and the combinations of them. Two rigid origami patterns, Miura-ori and Arc-Miura, are chosen to generate the graded origami structures, and the geometric parameters of each pattern are studied. For engineering application, quasi-static three-point bending response of sandwich beams with graded Miura-ori core based on changing the number of units and changing both the length of crease lines and the sector angle is explored. The investigation reveals that sandwich beams with graded Miura-ori core have preferable energy absorption capability in this load situation compared with the normal Miura-ori core.
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