Publications (45)
Quasar Elemental Abundances at High Redshifts
M. Dietrich, F. Hamann, J. C. Shields +5
We examine rest-frame ultraviolet spectra of 70 high redshift quasars (z>3.5) to study the chemical enrichment history of the gas closely related to the quasars, and thereby estima…
The Wide-Angle Outflow of the Lensed z = 1.51 AGN HS 0810+2554
G. Chartas, M. Cappi, F. Hamann +4
We present results from X-ray observations of the gravitationally lensed z = 1.51 AGN HS 0810+2554 performed with the Chandra X-ray Observatory and XMM-Newton. Blueshifted absorpti…
A High-Velocity Narrow Absorption Line Outflow in the Quasar J212329.46-005052.9
F. Hamann, N. Kanekar, J. X. Prochaska +5
We report on a variable high-velocity narrow absorption line outflow in the redshift 2.3 quasar J2123-0050. Five distinct outflow systems are detected with velocity shifts from -97…
HST and Ground-Based Spectroscopy of Quasar Outflows: From Mini-BALs to BALs
E. A. Moravec, F. Hamann, D. M. Capellupo +3
Quasar outflows have been posited as a mechanism to couple super-massive black holes to evolution in their host galaxies. We use multi-epoch spectra from the Hubble Space Telescope…
Emergence of a Quasar Outflow
F. Hamann, K. F. Kaplan, P. Rodriguez Hidalgo +2
We report the first discovery of the emergence of a high-velocity broad-line outflow in a luminous quasar, J105400.40+034801.2 at redshift z ~ 2.1. The outflow is evident in ultrav…
Variable Unidentified Emission Near 6307 AA in Eta Carinae
J. C. Martin, K. Davidson, F. Hamann +2
We have discovered a conspicuous unidentified variable feature near 6307 AA in the spectrum of Eta Carinae which is spatially unresolved from the central star and its wind (r < 200…
Continuum and Emission Line Strength Relations for a large Active Galactic Nuclei Sample
M. Dietrich, F. Hamann, J. C. Shields +5
We report on the analysis of a large sample of 744 type 1 Active Galactic Nuclei, including quasars and Seyfert 1 galaxies across the redshift range from 0 < z < 5 and spanning nea…
XQ-100: A legacy survey of one hundred 3.5 < z < 4.5 quasars observed with VLT/XSHOOTER
S. Lopez, V. D'Odorico, S. L. Ellison +23
We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift universe…
Preliminary Analysis of STIS-HST Spectra of Compact Ejecta from Eta Carinae
F. Hamann, K. Davidson, K. Ishibashi +1
We describe some preliminary results from spatially-resolved spectroscopy of the compact ejection knots B and D in the Eta Carinae wind. We emphasize various line diagnostics of th…
ERQs are the BOSS of Quasar Samples: The Highest-Velocity [OIII] Quasar Outflows
S. Perrotta, F. Hamann, N. L. Zakamska +3
We investigate Extremely Red Quasars (ERQs), a remarkable population of heavily-reddened quasars at redshift z2 - 3 that might be caught during a short-lived 'blow-out' phase…
Partial Coverage and Time Variability of Narrow-Line Intrinsic QSO Absorption Systems
Thomas A. Barlow, F. Hamann, W. L. W. Sargent
It is possible to distinguish ``intrinsic'' absorption systems (gas clouds within the quasar environment) from ``intervening'' systems (gas clouds unrelated to the quasar phenomeno…
Chemical Abundances in Broad Emission Line Regions: The "Nitrogen-Loud" QSO 0353-383
J. A. Baldwin, F. Hamann, K. T. Korista +3
The intensity of the strong N V 1240 line relative to C IV 1549 or to He II 1640 has been proposed as an indicator of the metallicity of QSO broad emission line regions, allowing a…
Host galaxies of luminous z0.6 quasars: Major mergers are not prevalent at the highest AGN luminosities
C. Villforth, T. Hamilton, M. M. Pawlik +10
Galaxy interactions are thought to be one of the main triggers of Active Galactic Nuclei (AGN), especially at high luminosities, where the accreted gas mass during the AGN lifetime…
The host galaxies of FeLoBAL quasars at z0.9 are not dominated by recent major mergers
C. Villforth, H. Herbst, F. Hamann +4
Theoretical models have suggested an evolutionary model for quasars, in which most of luminous quasars are triggered by major mergers. It is also postulated that reddening as well…
High Velocity Outflows in Narrow Absorption Line Quasars
G. Chartas, J. Charlton, M. Eracleous +6
The current paradigm for the AGN phenomenon is a central engine that consists of an inflow of material accreting in the form of a disk onto a supermassive black hole. Observations…
The X-Rays wind connection in PG 2112+059
C. Saez, W. N. Brandt, F. Bauer +4
We study the connection between the X-ray and UV properties of the broad absorption line (BAL) wind in the highly X-ray variable quasar PG 2112+059 by comparing Chandra-ACIS data w…
Elemental Abundances in the Broad Emission Line Region of Quasars at Redshifts larger than 4
M. Dietrich, I. Appenzeller, F. Hamann +4
We present observations of 11 high redshift quasars ($3.9 \la z \la 5.0$) observed with low spectral resolution in the restframe ultraviolet using FORS 1 at the VLT UT 1. The emiss…
The Complete Ultraviolet Spectrum of the Archetypal "Wind-Dominated" Quasar Mrk~231: Absorption and Emission from a High-Speed Dusty Nuclear Outflow
S. Veilleux, M. Melendez, T. M. Tripp +2
New near- and far-ultraviolet (NUV and FUV) HST spectra of Mrk 231, the nearest quasar known, are combined with ground-based optical spectra to study the remarkable dichotomy betwe…
Hunting for Metals Using XQ-100 Legacy Survey Composite Spectra
S. Perrotta, V. D'Odorico, F. Hamann +10
We investigate the NV absorption signal along the line of sight of background quasars, in order to test the robustness of the use of this ion as criterion to select intrinsic (i.e.…
The Mass of Quasar Broad Emission Line Regions
J. A. Baldwin, G. J. Ferland, K. T. Korista +2
We show that the mass of ionized gas in the Broad Line Regions (BLRs) of luminous QSOs is at least several hundred Msun, and probably of order 10^3-10^4 M_sun. BLR mass estimates i…
Quasar Metal Abundance and FIR Luminosity
L. E. Simon, F. Hamann
We compare the metallicities in high-redshift quasars to the star formation rates (SFR) in their host galaxies using measurements of broad emission lines and far-infrared (FIR) lum…
Hubble Space Telescope Observations of Extended [O III] λ5007 Emission in Nearby QSO2s: New Constraints On AGN / Host Galaxy Interaction
Travis C. Fischer, S. B. Kraemer, H. R. Schmitt +15
We present a Hubble Space Telescope (HST) survey of extended [O III] λ5007 emission for a sample of 12 nearby (z < 0.12), luminous Type 2 quasars (QSO2s), which we use to measure…
The Dependence of C IV Broad Absorption Line Properties on Accompanying Si IV and Al III Absorption: Relating Quasar-Wind Ionization Levels, Kinematics, and Column Densities
N. Filiz Ak, W. N. Brandt, P. B. Hall +10
We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are presen…
Quasar Elemental Abundances and Host Galaxy Evolution
F. Hamann, M. Dietrich, B. Sabra +1
High redshift quasars mark the locations where massive galaxies are rapidly being assembled and forming stars. There is growing evidence that quasar environments are metal-rich out…
Morphologies of z~0.7 AGN Host Galaxies in CANDELS: No trend of merger incidence with AGN luminosity
C. Villforth, F. Hamann, D. J. Rosario +24
The processes that trigger Active Galactic Nuclei (AGN) remain poorly understood. While lower luminosity AGN may be triggered by minor disturbances to the host galaxy, stronger dis…
Discovery of a 2 Kpc Binary Quasar
G. A. Shields, V. Junkkarinen, E. A. Beaver +4
LBQS 01032753 is a binary quasar with a separation of only 0.3 arcsec. The projected spacing of 2.3 kpc at the distance of the source (z = 0.848) is much smaller than that of an…
Ionization and Abundances in Intrinsic QSO Absorption-Line Systems
F. Hamann, T. Barlow, R. D. Cohen +2
We discuss two aspects of the ionization and abundances in QSO intrinsic absorbers. First, we use the high-ionization doublet Ne VIII 770,780 to test the relationship between the U…
Hubble Space Telescope Observations of [O~III] Emission in Nearby QSO2s: Physical Properties of the Ionised Outflows
Anna Trindade Falcao, S. B. Kraemer, T. C. Fischer +14
We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph (STIS) long-slit G430M and G750M spectra to analyse the extended [O~III] 5007A emission in a sample of twe…
The Origin of Fe II Emission in AGN
J. A. Baldwin, G. J. Ferland, K. T. Korista +2
We used a very large set of models of broad emission line (BEL) clouds in AGN to investigate the formation of the observed Fe II emission lines. We show that photoionized BEL cloud…
First results from the JWST Early Release Science Program Q3D: Benchmark Comparison of Optical and Mid-IR Tracers of a Dusty, Ionized Red Quasar Wind at z=0.435
D. S. N. Rupke, D. Wylezalek, N. L. Zakamska +27
The [OIII] 5007 A emission line is the most common tracer of warm, ionized outflows in active galactic nuclei across cosmic time. JWST newly allows us to use mid-infrared spectral…
LBQS 0103-2753: A 0.3 Arcsec Binary Quasar
V. Junkkarinen, G. A. Shields, E. A. Beaver +4
Imaging and spectroscopy with HST show that LBQS 0103-2753 (V = 17.8, z = 0.848) is a binary quasar with a separation of 0.3 arcsec or 2.3 kpc. This is by far the smallest separati…
A Change in the Physical State of Carinae?
K. Davidson, J. C. Martin, R. M. Humphreys +8
During Car's spectroscopic event in mid-2003, the stellar wind's bright H and H emission lines temporarily had a distinctive shape unlike that reported on any previous…
The Host Galaxies and Narrow Line Regions of Four Double-Peaked [OIII] AGN
C. Villforth, F. Hamann
Major gas-rich mergers of galaxies are expected to play an important role in triggering and fuelling luminous AGN. We present deep multi-band (u/r/z) imaging and long slit spectros…
Broad Absorption Line Variability on Multi-Year Timescales in a Large Quasar Sample
N. Filiz Ak, W. N. Brandt, P. B. Hall +10
We present a detailed investigation of the variability of 428 C IV and 235 Si IV Broad Absorption Line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sl…
The Surprising Absence of Absorption in the Far-Ultraviolet Spectrum of Mrk 231
S. Veilleux, M. Trippe, F. Hamann +11
Mrk 231, the nearest (z = 0.0422) quasar, hosts both a galactic-scale wind and a nuclear-scale iron low-ionization broad absorption line (FeLoBAL) outflow. We recently obtained a f…
Thomson Thick X-ray Absorption in a Broad Absorption Line Quasar PG0946+301
S. Mathur, P. J. Green, N. Arav +14
We present a deep ASCA observation of a Broad Absorption Line Quasar (BALQSO) PG0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any ot…
The Quasar-frame Velocity Distribution of Narrow CIV Absorbers
D. Nestor, F. Hamann, P. Rodriguez Hidalgo
We report on a survey for narrow (FWHM < 600 km/s) CIV absorption lines in a sample of bright quasars at redshifts in the Sloan Digital Sky Survey. Our main goal…
Elemental Abundances from Intrinsic QSO Emission and Absorption Lines
F. Hamann
Several studies have shown that the column densities inferred from broad absorption lines (BALs) require extremely high metallicities and phosphorus overabundances -- apparently in…
FeII/MgII Emission Line Ratio in High Redshift Quasars
M. Dietrich, F. Hamann, I. Appenzeller +1
We present results of the analysis of near infrared spectroscopic observations of 6 high-redshift quasars (z > 4), emphasizing the measurement of the ultraviolet FeII/MgII emission…
HST UV and Keck HIRES Spectra of BAL Quasars
V. Junkkarinen, R. D. Cohen, T. A. Barlow +1
In the analysis of broad absorption line (BAL) quasar spectra, Keck HIRES spectra are a useful complement to lower resolution HST and ground based spectra. The HIRES spectra provid…
How Massive Are BALQSO Winds?
F. Hamann, B. Sabra, V. Junkkarinen +2
We are involved in a program to derive properties of broad absorption line (BAL) winds in quasars using combined UV and X-ray observations. A major obstacle is large uncertainties…
Magnified Views of the Ultrafast Outflow of the z = 1.51 AGN HS 0810+2554
G. Chartas, F. Hamann, M. Eracleous +5
We present results from an observation of the gravitationally lensed z=1.51 narrow absorption line AGN HS 0810+2554 performed with the Chandra X-ray Observatory. The factor of ~100…
High-Velocity Narrow-Line Absorbers in QSOs
F. Hamann, T. Barlow, R. D. Cohen +2
We discuss the identification and kinematics of intrinsic narrow-line absorbers in three QSOs. The line-of-sight ejection velocities in the confirmed intrinsic systems range from 1…
Hubble Space Telescope [O III] Emission-Line Kinematics in Two Nearby QSO2s: A Case for X-ray Feedback
Anna Trindade Falcão, S. B. Kraemer, T. C. Fischer +15
We present a dynamical study of the narrow-line regions in two nearby QSO2s. We construct dynamical models based on detailed photoionization models of the emission-line gas, includ…
X-Ray Absorption Associated with High-Velocity UV Absorbers
B. M. Sabra, F. Hamann, J. C. Shields +2
We present Chandra observations of two radio-quiet QSOs, PG 2302+029 and PG 1254+047. PG 2302+029 has an ultra high-velocity UV absorption system -56,000 km/s, while PG 1254+047 is…