This research focuses on understanding the formation and evolution of galaxies via their extended gaseous halos using the methods of quasar absorption line systems. Galaxy-absorber pairs provide direct observational constraints on competing scenarios aimed at establishing the role of gas in galaxy formation and ...

The galaxy (or system of galaxies) VV 617 has been observed with the 6-m reflector. The emission-line widths correspond to approx. =1000 km/sec, so the object is apparently a class 2 Seyfert galaxy. Although very faint in the B wavelength band, the nucleus is exceptionally bright in R. If its color excess is due to ...

emission and Ca ii H and K absorption, are expected for z > 1 galaxies. In the LRIS blue side, we used the 300 lines mm1 grating blazed at 5000 A? . ...

The spectra were collected with the LRIS on the Keck II Telescope, which has a 7.7arcmin long slit. We selected galaxies from Palomar Observatory Sky Survey prints of the centre of the Coma cluster. (2 data files).

We have directly compared Mg II halo gas kinematics to the rotation velocities derived from emission/absorption lines of the associated host galaxies. Our 0.096 <= z <= 0.148 volume-limited sample comprises 13 ~L sstarf galaxies, with impact parameters of 12-90 kpc from background quasar sight lines, associated with 11 Mg II ...

MgII QSO absorption lines detected in the spectra of background QSOs were used over a decade ago to infer that all redshift z > 0.2 galaxies have gaseous halos of radius ~ 60 kpc. The actual size of the halo was believed to be proportional to the luminosity of the galaxy. However, these conclusions are now much harder to understand ...

MgII absorption lines detected in the spectra of background quasars allow us to probe the cool metal-enriched halo gas associated with foreground galaxies. This technique allows us to directly study the complex halo gas which provides the fuel for star-forming disks. The dynamics of this gas is likely driven by one or more of the following physical ...

... near the center of the galaxy rather than to ... Descriptors : (*GALAXIES, MICROWAVE SPECTROSCOPY), (*INTERSTELLAR MATTER, HYDROGEN ...

A complete picture of galaxy formation can only be obtained by detailed study of the processes by which galaxies convert their gas into stars. One approach is to relate the H I gas and the stars in galaxies. Damped and sub-damped Lyman-? systems (DLAs), which are galaxies probed by the ...

The aim of this project is to identify low-redshift host galaxies of quasar absorption-line systems by selecting galaxies that are seen in projection onto quasar sightlines. To this end, we use the Seventh Data Release of the Sloan Digital Sky Survey to construct a parent sample of 97,489 ...

We investigate the properties of H I-rich galaxies detected in blind radio surveys within the hierarchical structure formation scenario using a semianalytic model of galaxy formation. By drawing a detailed comparison between the properties of H I-selected galaxies and H I absorption systems, we ...

We have used Galaxy IMage 2D (GIM2D) to quantify the morphological properties of 40 intermediate-redshift Mg II absorption-selected galaxies [0.03 ? Wr(2796) ? 2.9 �], imaged with WFPC-2/Hubble Space Telescope (HST), and compared them to the halo gas properties measured from HIRES/Keck and UVES/VLT quasar spectra. We find that as the ...

We have used Galaxy IMage 2D (GIM2D) to quantify the morphological properties of 40 intermediate-redshift Mg II absorption-selected galaxies [0.03 ? Wr(2796) ? 2.9 �], imaged with WFPC-2/Hubble Space Telescope (HST), and compared them to the halo gas properties measured from HIRES/Keck and UVES/VLT quasar spectra. We find that as the ...

We develop a new diagnostic method to classify galaxies into active galactic nucleus (AGN) hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/H? ratio with rest-frame U - B color. This can be used to robustly select AGNs in galaxy ...

This project involves a photometric study of galaxies seen through the bodies of several Local Group galaxies. The high resolution of WFPC2 images will be used with automated techniques to identify galaxies at various magnitude limits. For three different magnitude regimes we will use three different techniques for studying the optical ...

We propose to observe the nuclear regions of four starburst galaxies and two ULIRGs using the HET/MRS telescope and instrument. The starburst galaxies were selected from a sample Na I absorbers in which the Na I is primarily due to either interstellar absorption or circumstellar absorption. We ...

We have searched for active galactic nuclei (AGNs) in K+A galaxies, using multiwavelength imaging and spectroscopy in the Booetes field of the NOAO Deep Wide-Field Survey. The K+A galaxies, which have had their star formation rapidly truncated, are selected via their strong Balmer absorption lines and weak Halpha ...

Studies of faint, distant galaxies have greatly advanced in recent years. It is now possible to observe hundreds of galaxies out to z=1 and in the range 3 < z < 3.5, yet galaxies in the redshift range 1 < z < 3 remain largely unexplored. Galaxies selected by MgII ...

We introduce our survey of galaxy groups at 0.85 < z < 1, as an extension of the Group Environment and Evolution Collaboration. Here we present the first results, based on Gemini GMOS-S nod-and-shuffle spectroscopy of seven galaxy groups selected from spectroscopically confirmed, extended XMM detections in COSMOS. We use ...

The metallicity of galaxies and its evolution with redshift is of paramount importance for understanding galaxy formation. Abundances in the interstellar medium {ISM} are typically determined using emission-line spectroscopy of HII regions. However, since HII regions are associated with recent SF they may not have abundances typical for the ...

We examine the properties of two galaxy ``halos'' at z~0.7 in the Ton 153 (zem=1.01) quasar field. The first absorber-galaxy pair (G1) is a z=0.672, LB=4.3L*B, E/S0 galaxy probed at D=58 kpc. G1 is associated with a remarkable five-component Ly? complex having ?LL<=0.4, Wr(Ly?)=2.8 �, and a velocity spread of ?v=1420 km s-1. We ...

The HST/ACS Coma Cluster Treasury Survey addresses many outstanding issues concerning galaxy formation, and provides a fundamental low-redshift reference, and comparison dataset for cluster studies at high redshift. We present preliminary results from our follow-up Keck/DEIMOS spectroscopic survey, which targets galaxies in the dense cluster core. Accurate ...

We report on the motivation, sample selection and first results of our VLT FORS2 Large Programme (173.A-0687), which has obtained the longest targeted spectra of distant galaxies obtained so far with the VLT. These long exposures, up to 77 hours for objects included in three masks, were required to detect spectral features of extremely faint ...

Strong Balmer absorption lines and the lack of H? and [OII] emission lines signify that E+A galaxies are post-starburst systems. Recent studies suggest that E+As may undergo the transition from the `blue cloud' to the `red sequence' and eventually migrate to red-sequence early-type galaxies. An observational validation of this scenario ...

We present some early results from a deep KECK-DEIMOS spectroscopic survey of 2000 z > 3.5 galaxies in the Cosmic Evolution Survey (COSMOS) field. The extensive COSMOS photometric data set has provided us with one of the largest samples of galaxies at 3.5 < z < 6, identified using photometric redshifts as well as Lyman Break ...

The Lyman-? (Ly?) emission line is the primary observational signature of star-forming galaxies at the highest redshifts, and has enabled the compilation of large samples of galaxies with which to study cosmic evolution. The resonant nature of the line, however, means that Ly? photons scatter in the neutral interstellar medium of their host ...

... Accession Number : AD0773573. Title : A Study of the HI Absorption in the Galaxy M82 by Radio Interferometry,. Corporate ...

Aims: The identities of the main processes triggering and quenching star-formation in galaxies remain unclear. A key stage in evolution, however, appears to be represented by post-starburst galaxies. To investigate the prevalence of these galaxies and their impact on galaxy evolution in general, we initiated a ...

We propose to obtain high resolution WFPC2 images of the field of 3C 336, a quasar with z=0.927 in whose spectrum 3 foreground MgII absorption systems with z= 0.472, 0.656, and 0.892 are known, making it the richest field in a nearly completed survey for absorption--selected galaxies which we have been conducting using ground-based ...

Unusually extended neutral gas disks have been found in both spiral and irregular galaxies. For these galaxies, the extent of the HI is unusual in the sense that "normal" galaxies have HI-to-optical diameter ratios of approximately two (Broeils & Rhee 1997), whereas these galaxies have ratios that often exceed ...

We have conducted a spectroscopic survey of 78 starbursting infrared-luminous galaxies at redshifts up to z=0.5. We use moderate-resolution spectroscopy of the Na I D interstellar absorption feature to directly probe the neutral phase of outflowing gas in these galaxies. Over half of our sample are ultraluminous infrared ...

Abstract. We present the results of a survey of galaxies selected by their gas cross-section which give rise to Mg ii absorption lines in the spectra of background quasars. The sample comprises 11 galaxies covering the redshift range 0.7

The metallicity of galaxies and its evolution with redshift is of paramount importance for understanding galaxy formation. Abundances in the interstellar medium (ISM) are typically determined using emission-line spectroscopy of H ii regions. However, since H ii regions are associated with recent SF they may not have abundances typical for the ...

Rest-frame UV spectral lines of star-forming galaxies are systematically offset from the galaxies' systemic redshifts, probably because of large-scale outflows. We calibrate galaxy redshifts measured from rest-frame UV lines by utilizing the fact that the mean H I Ly? absorption profiles around the ...

We present an H I 21 cm absorption survey with the Green Bank Telescope (GBT) of galaxy-quasar pairs selected by combining galaxy data from the Sloan Digital Sky Survey (SDSS) and radio sources from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. Our sample consists of 23 sight lines through ...

We show that the dependence of Ly? absorption on environment leads to significant non-gravitational features in the redshift space power spectrum of Ly? selected galaxies. We derive a physically motivated fitting formula that can be included in clustering analyses, and use this to discuss the predicted features in the Ly? ...

The small projected separations of some QSO's and low-redshift galaxies provide unique opportunities to study the extent and content of gas in galaxies through observation of absorption in the QSO spectra. Observations of these systems provide valuable in...

Aims: To investigate the dependence of the occurrence of active galactic nuclei (AGNs) on local galaxy density, we study the nuclear properties of ~5000 galaxies in the Coma supercluster whose density spans two orders of magnitude from the sparse filaments to the cores of rich clusters. Methods: We obtained optical spectra of the nuclei of 283 ...

We present new results for a sample of 33 narrow-lined UV-selected active galactic nuclei (AGNs), identified in the course of a spectroscopic survey for star-forming galaxies at z ~ 2-3. The rest-frame UV composite spectrum for our AGN sample shows several emission lines characteristic of AGNs, as well as interstellar absorption ...

We present the first results from the Complete Optical and Radio Absorption Line System (CORALS) survey for Damped Lyman Alpha (DLA) systems based on a radio-selected sample of quasars. We find that the number density and neutral gas content of CORALS DLAs is in good agreement with previous surveys. These results indicate that dust obscuration has probably ...

With their high H I column densities, the Damped Lyman-(alpha) systems (DLAs) and sub-DLAs seen in the spectra of QSOs are thought to be closely related to galaxies. As these systems are selected based on their absorption properties, followup imaging is necessary and important to study the stellar component of these systems. The DLA ...

A sample of nearly 9000 early-type galaxies, observed in the g*, r*,i*, and z* bands, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The sample spans the redshift range 0 < z < 0.3, and was used to study how early-type galaxy observables, including luminosity, effective radius, surface ...

A sample of nearly 9000 early-type galaxies, observed in the g*,r*,i*, and z* bands, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The sample spans the redshift range 0 < z < 0.3, and was used to study how early-type galaxy observables, including luminosity, effective radius, surface ...

We present absorption-line index gradients for a sample of S0 galaxies in the Fornax cluster. The sample has been selected to span a wide range in galaxy mass, and the deep FORS2 spectroscopy on the VLT allows us to explore the stellar populations all the way to the outer disc-dominated regions of these ...

Due to its short lifetime the K+A phenomenon, characterized by strong Balmer absorption with no significant emission lines, marks an important stage during the evolution of spheroidal galaxies. We have developed an efficient photometric technique for identifying K+A galaxy candidates using a combination of photometric redshifts and ...

Compton-thick Active Galactic Nuclei (AGN), accreting supermassive black holes at the centers of galaxies surrounded by absorbing material with a column density (NH > 1024 cm-2), are common in the local universe. To determine an unbiased estimate of the fraction of heavily obscured AGN and to study their properties, we have analyzed two samples of Seyfert 2 ...

In this paper we present the three-dimensional dynamics of the galaxy SDSS J101345.39+011613.66, selected for its unusually strong Balmer absorption lines [W0(H?)=7.5 �]. Using the Gemini Multi-Object Spectrograph-South integral field unit (IFU) in nod+shuffle mode, we have mapped the continuum and optical ...

In this contribution we present a few selected examples of how the latest generation of space-based instrumentation --- NASA's Chandra X-ray Observatory and the Far-Ultraviolet Spectroscopic Explorer ( FUSE) --- are finally answering old questions about the influence of massive star feedback on the warm and hot phases of the ISM and IGM. In particular, we discuss the ...

We investigate the intrinsic opacity of high-redshift galaxies to outgoing ionizing photons using high-quality photometry of a sample of 27 spectroscopically identified galaxies of redshift 1.9 < z < 3.5 in the Hubble Deep Field. Our measurement is based on maximum-likelihood fitting of model galaxy spectral energy distributions ...

Current models of galaxy evolution require that galactic-scale gaseous outflows play an integral role in shaping the observed galaxy stellar mass function. The implementation of winds in these models, however, has been primarily via ad hoc prescriptions, as the physics driving such outflows is not understood. In particular, theoretical studies suggest that ...

We propose to address two of the biggest open questions in galaxy formation - how galaxies acquire their gas and how they return it to the IGM - with a concentrated COS survey of diffuse multiphase gas in the halos of SDSS galaxies at z = 0.15 - 0.35. Our chief science goal is to establish a basic set of observational facts about the ...

Optical nebular emission lines are commonly used to estimate the star formation rate of galaxies and the black hole accretion rate of their central active nuclei. The accuracy of the conversion from line strengths to physical properties depends upon the accuracy to which the lines can be corrected for dust attenuation. For studies of single galaxies with ...

NGC 3516, a low-luminosity Seyfert galaxy, is one of a small fraction of Seyfert galaxies that exhibit broad absorption in a resonance line. In order to determine whether the UV and x ray absorption in NGC 3516 are related, 5 IUE observations were obtaine...

Nov 24, 2000 ... How are the "Local Group" of galaxies selected? Are they just galaxies that are close to each other or are they connected by other means (By ...

We present wide-field, imagery and photometry of 43 selected nearby galaxies of all morphology types

Star forming galaxies represent a small yet sizable fraction of the X-ray sky (1%-20%, depending on the flux). X-ray surveys allow to derive their luminosity function and evolution, free from uncertainties due to absorption. However, much care must be put in the selection criteria to build samples clean from contamination by AGN. Here ...

Galaxies found under the Glare of Cosmic Flashlights Astronomers using ESO's Very Large Telescope have discovered in a single pass about a dozen otherwise invisible galaxies halfway across the Universe. The discovery, based on a technique that exploits a first-class instrument, represents a major breakthrough in the field of galaxy ...

Mar 5, 2007... neighbor galaxy, which we interpret as [OII], and weak Calcium H and K absorption we infer a redshift of z=0.841+/-0.001 for the galaxy. ...

This site is a collection of lecture notes for a course called the universe of galaxies. These notes discuss the integrated properties, classification, stellar and gaseous content of galxies; galaxies within, gasesous content, and the evolution of clusters of galaxies; QSOs, Seyfert nuclei, radio galaxies, and the ...

We analyze the influence of the evolution of light absorption by gray dust in the host galaxies of type Ia supernovae (SN Ia) and the evolution of the mean combined mass of close-binary carbon-oxygen white dwarfs merging due to gravitational waves (SN Ia precursors) on the interpretation of Hubble diagrams for SN Ia. A significant increase in the mean SN ...

This program is the continuation of the Q106 program on the study of the OVI phase in galactic halos. We have selected a third quasar, Q0026+1259 (Bowen & Blades, 1997). Two galaxies lie close to the quasar sightline, which could give rise to OVI absorption lines, which FUSE only would be able to detect. The quasars has a flux ...

To search for low-redshift damped Ly? (DLA) and sub-DLA quasar absorbers, we have conducted a 21 cm absorption survey of radio-loud quasars at small impact parameters to foreground galaxies selected from the Sloan Digital Sky Survey (SDSS). Here we present the first results from this survey based on observations of SDSS ...

Gamma-ray bursts (GRBs) are cosmologically distributed, very energetic and very transient sources detected in the gamma-ray domain. The identification of their x-ray and optical afterglows allowed so far the redshift measurement of 150 events, from z = 0.01 to z = 6.29. For about half of them, we have some knowledge of the properties of the parent galaxy. At high redshift (z ...

Surveys of AGN taken in the optical, UV, and soft X-rays miss an important population of obscured AGN only visible in the hard X-rays and mid-IR wavelengths. The SWIFT BAT survey in the hard X-ray range (14-195 keV) has provided a uniquely unbiased sample of 246 AGN unaffected by galactic or circumnuclear absorption [1]. Most of the sources in the survey are bright, Seyfert ...

AGN exhibit a variety of spectral energy distributions whose shapes depend on the intrinsic properties of the AGN, the extinction and absorption suffered by the nuclear radiation and the contribution of the host galaxy. Here, the intrinsic AGN spectral energy distributions of a hard X-ray selected sample of AGN from the XMDS are ...

. Even without internal HI absorption, comparison of the distribution of simulated colors to the analytic HI absorption internal to the galaxies generaly diminishes the scatter in the observed colors in the expected colors of high redshift galaxies due to a range of (and variations in) LOS ...

Outline Absorption Chemical evolution STRUCTURE OF GALAXIES 8. Absorption; chemical evolution Piet Piet van der Kruit, Kapteyn Astronomical Institute Absorption; chemical evolution #12;Outline Absorption Chemical evolution Outline Absorption Holmberg's analysis Analysis of ...

We report on observations of Lyman break galaxies (LBGs) selected from the Great Observatories Origins Deep Survey at mean redshifts z ~ 4, 5, and 6 (B 435-, V 606-, and i 775-band dropouts, respectively), obtained with the red-sensitive FORS2 spectrograph at the ESO VLT. This program has yielded spectroscopic identifications for 114 ...

We study the stellar populations of 1923 elliptical galaxies at z < 0.05 selected from the Sloan Digital Sky Survey as a function of velocity dispersion, {sigma}, and environment. Our sample constitutes among the largest high-fidelity samples of elliptical galaxies with uniform imaging and optical spectroscopy assembled to date. ...

We have obtained optical spectra of 29 early-type (E/S0) galaxies that hosted Type Ia supernovae (SNe Ia). We have measured absorption-line strengths and compared them to a grid of models to extract the relations between the supernova properties and the luminosity-weighted age/composition of the host galaxies. Such a direct measurement ...

This thesis presents observational results detailing the state of the Universe ~5-9 billion years ago, focusing primarily on the spatial distribution and clustering of galaxies. We first present optical spectra, obtained with the Keck 10-m telescope, of two high-redshift type Ia supernovae (SNe Ia) at maximum light, discovered by the High-z Supernova Search Team: SN 1999ff at ...

We present a spectroscopic study of the stellar populations of LINERs and LINER/HII Transition Objects (TOs). Our main goal is to determine whether the stars who live in the innermost regions of these low luminosity active galaxies are in some way related to their emission line properties, which would imply in a link between the stellar population and the gas excitation ...

Aims:We analysed the physical properties of z �4 Lyman Break Galaxies observed in the GOODS-S survey, in order to investigate possible differences between galaxies where the Ly? is present in emission, and those where the line is absent or in absorption. Methods: The objects were selected from their optical ...

High redshift radio galaxies (HzRGs) provide unique targets for the study of the formation and evolution of massive galaxies and galaxy clusters at very high redshifts. We discuss how efficient HzRG samples ae selected, the evidence for strong morphologic...

By using cluster analysis, we select a galaxy pair sample in the Sloan Great Wall and study its various properties. We find that in the Sloan Great Wall pair sample, most galaxies are brighter and smaller, and that there is a tendency for pair galaxies to have similar luminosity and size.

Low Surface Brightness (LSB) galaxies are an important but often neglected part of the galaxy content of the universe. Their importance stems both from the selection effects which cause them to be under-represented in galaxy catalogs, and from what they c...

We explore the properties of 24 field early-type galaxies in the redshift range 0.20 < z < 0.75 down to MB <= -19.30 in a sample extracted from the FORS Deep Field and the William Herschel Deep Field. Target galaxies were selected on the basis of a combination of luminosity, spectrophotometric type, morphology and photometric ...

The environments of luminous radio-loud quasars (RLQs) evolve rapidly with redshift: at z=0.6 they are often as rich as Abell class 1 clusters, but at z<0.5 they are never so rich. This rapid, unexplained evolution indicates that the evolution of quasars is tied to their environments. The outstanding feature of quasar evolution is the huge decline in space density from z=2 to z=0, but almost ...

We investigate the optical morphologies of candidate active galaxies identified at radio, X-ray, and mid-infrared wavelengths. We use the Advanced Camera for Surveys General Catalog (ACS-GC) to identify 372, 1360, and 1238 active galactic nucleus (AGN) host galaxies from Very Large Array, XMM-Newton, and Spitzer Space Telescope observations of the COSMOS ...

We present the results from our 21-cm absorption survey of a sample of five quasar-galaxy pairs (QGPs), with the redshift of the galaxies in the range 0.03 <= zg <= 0.18, selected from the Sloan Digital Sky Survey (SDSS). The HI 21-cm absorption was searched towards the nine sightlines ...

Five X-ray selected Seyfert galaxies were examined via near-simultaneous far-ultraviolet and optical

We present the results of a mini-survey for associated H I 21-cm absorption at z? 0.42 with the Giant Metrewave Radio Telescope. Our targets are radio galaxies, selected on the basis that the ?? 1216 � luminosities are below LUV� 1023 W Hz-1, above which there has never been a detection of 21-cm absorption. Of ...

The X-ray absorption model can be computed for various metallicities by sim- ple scaling of the Solar abundances by a constant factor. ...

The stronger resonant X-ray lines from the intracluster gas should be observable as absorption lines

The controversy over whether the absorption spectrum in QSOs is intrinsic or extrinsic is approached

(1977), the authors reexamine the possibility multiple absorption spectra of QSOs are due to gas in the disks, coronae, or halos of intervening galaxies. ...

The hypothesis that the population of strong H I absorption systems is responsible for a significant

photoelectric absorption model such as phabs. The extinction curve contains no spectral features and is characterized by a powerlaw slope over spectral ...

We report the spectroscopic confirmation of two Lyman break galaxies at redshift >7. The galaxies were observed as part of an ultra-deep spectroscopic campaign with FORS2 at the ESO/VLT for the confirmation of z ~= 7 "z-band dropout" candidates selected from our VLT/Hawk-I imaging survey. Both galaxies show a ...

We study X-ray to K-band luminosity ratios (LX/LK) of late-type galaxies in the 0.3-0.7 keV energy range. From the Chandra archive, we selected nine spiral and three irregular galaxies with point source detection sensitivity better than 5 � 1036 erg s-1 in order to minimize the contribution of unresolved X-ray binaries. In late-type ...

Virtually all of our current knowledge of black hole demographics, both in nearby inactive galaxies and in AGNs, comes from observations of black holes with masses between a few million and a few billion solar masses in host galaxies with stellar velocity dispersions between about 70 and 400 km/sec. Searching for smaller black holes in low-mass ...

We investigate the role of host galaxy classification and black hole mass (MBH) in a heterogeneous sample of 276 mostly nearby (z < 0.1) X-ray and IR-selected active galactic nuclei (AGN). Around 90 per cent of Seyfert 1 AGN in bulge-dominated host galaxies (without disc contamination) span a very narrow range in the observed 12?m ...

We have carried out a spectropolarimetric search for hidden broad-line quasars in three ultraluminous infrared galaxies (ULIRGs) discovered in the positional correlations between sources detected in deep radio surveys and the {ital IRAS} Faint Source Catalog. Only the high-ionization Seyfert 2 galaxy TF J1736{plus}1122 is highly polarized, displaying a ...

We have carried out a spectropolarimetric search for hidden broad-line quasars in three ultraluminous infrared galaxies (ULIRGs) discovered in the positional correlations between sources detected in deep radio surveys and the IRAS Faint Source Catalog. Only the high-ionization Seyfert 2 galaxy TF J1736+1122 is highly polarized, displaying a broad-line ...

The spectral FIR appearance of galaxies with nuclear starbursts or an active nuclear engine is investigated. The modeling results are compared with the FIR colors of a sample of superluminous galaxies and edge-on galaxies which display OH absorption and emission, and with the colors of a large sample of bright IRAS ...

The aim of this work is to estimate the number of Seyfert nuclei missing in catalogs due to obscuration by the dust disc in host spiral galaxies. We compared the distribution of inclinations of host galaxies of Sy1s and Sy2s with that of in control sample of spiral galaxies, and found that the relative number of Seyferts is higher in ...

We present five serendipitous spectroscopic interacting Lyman break galaxy (LBG) pairs and six candidate pairs from our z 3 Keck survey. All galaxies in the pairs exhibit Ly? in emission and we show that this is not a selection effect. A complete investigation of all LBG spectroscopic-photometric pairs with at least one ...

We present a search for intrinsic HI 21 cm and OH 18 cm absorption within the host galaxies of 143 compact radio sources in the redshift range 0.02 < z < 3.8. We use our results on 105 interference-free sources to test two hypotheses: (1) roughly half of compact radio sources show intrinsic 21 cm absorption, and (2) 21 cm ...

We present XMM-Newton observations of four low-redshift Seyfert galaxies selected to have low host luminosities (M{sub g} > - 20 mag) and small stellar velocity dispersions (sigma{sub *} <45 km s{sup -1}), which are among the smallest stellar velocity dispersions found in any active galaxies. These ...

We present new spectra of dominant galaxies in X-ray-selected clusters of galaxies, which combine with our previously published spectra to form a sample of 256 dominant galaxies in 215 clusters. 177 of the clusters are members of the ROSAT Brightest Cluster Sample (BCS; Ebeling et al.), and 17 have no previous ...

We have imaged a 45' x 45' area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to the limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2, respectively. The principal goals of the survey are to identify quasi-stellar objects (QSOs) and to map structure traced by luminous galaxies and QSO absorption line ...

Preliminary results are presented from a radio survey of galaxies detected by the IRAS minisurvey. It was found that the main difference between galaxies selected in the far infrared and those selected in the optical is that the former have higher radio l...

Multifiber optical spectroscopy has been performed on galaxies in the vicinity of strong, nearby radio galaxies. These radio galaxies were selected from the, 3CR and B2 catalogs based on their exclusion from the Abell catalog, which is puzzling given the ...

We present the first active galactic nuclei (AGN) census in a sample of 61 galaxies selected at 70?m, a wavelength which should strongly favour the detection of star-forming systems. For the purpose of this study, we take advantage of deep Chandra X-ray and Spitzer infrared (3.6-160?m) data, as well as optical spectroscopy and photometry from the Deep ...

The Lyman-alpha (Lyalpha) emission line is the primary observational signature of star-forming galaxies at the highest redshifts, and has enabled the compilation of large samples of galaxies with which to study cosmic evolution. The resonant nature of the line, however, means that Lyalpha photons scatter in the neutral interstellar medium of their host ...

This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, ...

A fundamental astrophysical question is the role of gas in galaxy evolution. Mg II absorption as observed in quasar spectra is found to arise in a broad range of gaseous galactic environments. But the overall relationship between the distribution of Mg II absorbers, their host galaxies, and the larger scale galactic structure is not ...

We have performed a spectroscopic study of seven Type 2 QSOs using the mid-infrared spectrometer IRS on board the Spitzer Space Telescope. These are (to our knowledge) the first mid-IR spectra of X-ray-selected QSO2s taken. The objects have been selected according to their high intrinsic luminosities and column densities in X-rays. Their spectra strongly ...

Surveys of AGN taken in the optical, UV, and soft X-rays miss an important population of obscured AGN only visible in the hard X-rays and mid-IR wavelengths. The SWIFT BAT survey in the hard X-ray range (14-195 keV) has provided a uniquely unbiased sample of 258 AGN unaffected by galactic or circumnuclear absorption. Optical imaging of this unbiased sample provides a new ...

Observations of the radio galaxy MRC 0316-257 at z = 3.13 and the surrounding field are presented. Using narrow- and broad-band imaging obtained with the VLT*, 92 candidate Ly{alpha} emitters with a rest-frame equivalent width of > 15 AngstromS were selected in a {approx} 7{prime} x 7{prime} field around the radio galaxy. ...

Using a sample of 92 UV continuum-selected, spectroscopically identified galaxies with langzrang = 2.65, all of which have been imaged in the Ly? line with extremely deep narrow-band imaging, we examine galaxy Ly? emission profiles to very faint surface brightness limits. The galaxy sample is representative of ...

We present ISO, VLA and BIMA observations of the CO and HI content in two collisional Seyfert galaxies-NGC 985 and NGC 1144 (Arp 118). Both systems exhibit signs that their molecular and atomic gas are in a highly transient state. Both appear to have a huge overabundance of molecular gas relative to atomic, only moderate far-IR luminosities, and both show highly disturbed ...

We report the discovery of a new gravitationally lensed quasar, SDSS J131339.98+515128.3, at a redshift of 1:875 with an image separation of 1: 0024. The lensing galaxy is clearly detected in visible-light follow-up observations. We also identify three absorption-line doublets in the spectra of the lensed quasar images, from which we measure the lens ...

The Medium Sensitivity Survey (MSS) quasar sample is being used more and more to study quasar properties in general and to analyze the relationship between X-ray-selected and optically selected quasars in particular. These studies have recently shown that current knowledge of the properties of optically selected quasars (luminosity ...

Spatially resolved spectroscopy has been obtained for a sample of 27 star-forming (SF) galaxies selected from our deep H? survey of the Hercules cluster. We have applied spectral synthesis models to all emission-line spectra of this sample using the population synthesis code STARLIGHT and have obtained fundamental parameters of stellar components such as ...

Aims: We study the influence of the environment on the evolution of galaxies by investigating the luminosity function (LF) of galaxies of different morphological types and colours at different environmental density levels. Methods: We construct the LFs separately for galaxies of different morphology (spiral and elliptical) and of ...

We examine a sample of 45 Mg II absorption-selected systems over the redshift range 0.4-1.4 in order to better understand the range of physical conditions present in the interstellar and halo gas associated with intermediate redshift galaxies. Mg II and Fe II absorption profiles were observed at a resolution of ~=6 km s-1 with ...

We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, ...

... of this systematic investigation is to gain further understanding of the details of various absorption features in the vicinity of the K absorption edge of ...

The chemical evolution of the high redshift intergalactic and interstellar media of galaxies is studied using QSO absorption lines. The redshift evolution of damped Lyman alpha (DLA) system metallicity is studied down to z=0.5, and no significant increase in metals is found. The CIV/HI ratio in the Lyman alpha forest is investigated at z approximately 3 ...

... Title : Scattering Coefficients and the Absorption Edge of Longitudinal Coherent Sound Waves in Selected Inhomogeneous Materials. ...

The cosmological evolution and the X-ray luminosity function of quasars and Seyfert galaxies (active

The X-ray and optical properties of a selection of compact nucleus, emission line Markarian galaxies

The large-scale distribution of groups of galaxies selected from complete slices of the CfA redshift

Lyman-break galaxies selected at visible wavelengths at z ~ 3 are thought to ... sensitive to detecting typical dusty galaxies at z ~ 3 and a comparison ...

Aug 11, 2010 ... Rings and arcs of ultraviolet light around a selection of galaxies imaged by Hubble Astronomers have found unexpected rings and arcs of ...

Jun 11, 2010 ... The properties of galaxy clusters and groups. ... and investigate the properties of an x-ray selected sample of galaxy clusters out to high ...