The Intrinsically X-ray Weak Quasar PHL 1811. II. Optical and UV Spectra and Analysis

Abstract

This is the second of two papers reporting observations and analysis of the unusually bright (m_b=14.4), luminous (M_B=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray weak, and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong FeII and FeIII, and unusual low-ionization lines such as NaID and CaII H&K are observed. High-ionization lines are very weak; CIV has an equivalent width of 6.6A, a factor of ~5 smaller than measured from quasar composite spectra. An unusual feature near 1200A can be deblended in terms of Lyα, NV, SiII, and CIII* using the blueshifted CIV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys are generally biased against finding similar objects.

Accepted for publication in ApJS. Full resolution figures available here: http://www.nhn.ou.edu/~leighly/phl1811_paper1.pdf

References in corpus (5)

• The X-ray-to-Optical Properties of Optically-Selected Active Galaxies Over Wide Luminosity and Redshift Ranges
• Chandra Observations of the Highest Redshift Quasars from the Sloan Digital Sky Survey
• The Intrinsically X-ray Weak Quasar PHL 1811. I. X-ray Observations and Spectral Energy Distribution
• The emission spectrum of the strong Fe II emitter BAL Seyfert 1 galaxy IRAS 07598+6508
• Quasars with Super Metal Rich Emission Line Regions

Cited by in corpus (79)

• X-ray Insights into the Nature of PHL 1811 Analogs and Weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk?
• High-Redshift SDSS Quasars with Weak Emission Lines
• Are Optically-Selected Quasars Universally X-Ray Luminous? X-Ray/UV Relations in Sloan Digital Sky Survey Quasars
• Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven
• Extremely Red Quasars in BOSS
• Self-shadowing Effects of Slim Accretion Disks in Active Galactic Nuclei: Diverse Appearance of the Broad-line Region
• {\it NuSTAR} Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231
• A Population of X-ray Weak Quasars: PHL 1811 Analogs at High Redshift
• Emergence of a Broad-Absorption-Line Outflow in the Narrow-line Seyfert 1 Galaxy WPVS 007
• Cold Accretion Disks and Lineless Quasars
• Weak Hard X-ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-ray Weakness
• X-ray and Multiwavelength Insights into the Nature of Weak Emission-Line Quasars at Low Redshift
• X-ray Properties of Intermediate-mass Black Holes in Active Galaxies. III. Spectral Energy Distribution and Possible Evidence for Intrinsically X-ray-weak AGNs
• Mining for Dust in Type 1 Quasars
• The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
• Weak Hard X-ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-ray Weakness?
• Weak-Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-Line Regions?
• Detection of Rest-frame Optical Lines from X-shooter Spectroscopy of Weak Emission Line Quasars
• Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?
• The NuSTAR Serendipitous Survey: The 40 month Catalog and the Properties of the Distant High Energy X-ray Source Population
• Evidence for AGN Feedback in the Broad Absorption Lines and Reddening of Mrk 231
• Weak Emission Line Quasars in the Context of a Modified Baldwin Effect
• Observable Consequences of Merger-Driven Gaps and Holes in Black Hole Accretion Disks
• On the structure and energetics of quasar broad absorption-line outflows
• X-ray Insights into the Nature of Weak Emission-Line Quasars at High Redshift
• Constraints on the black hole spin in the quasar SDSS J094533.99+100950.1
• The Complete Ultraviolet Spectrum of the Archetypal "Wind-Dominated" Quasar Mrk~231: Absorption and Emission from a High-Speed Dusty Nuclear Outflow
• Multiwavelength Observations of Radio-quiet Quasars with Weak Emission Lines
• Tracing the Outflow of a z=0.334 FeLoBAL: New Constraints from Low-Ionization Absorbers in FBQS J1151+3822
• Unusual quasars from the Sloan Digital Sky Survey selected by means of Kohonen self-organising maps
• Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092
• SDSS J094533.99+100950.1 - the remarkable weak emission line quasar
• Super-Eddington QSO RX J0439.6-5311. II. Multi-wavelength Constraints on the Global Structure of the Accretion Flow
• Testing AGN outflow and accretion models with CIV and HeII emission line demographics in z=2 quasars
• Improved Fe II emission line models for AGN using new atomic datasets
• The Surprising Absence of Absorption in the Far-Ultraviolet Spectrum of Mrk 231
• The z=0.54 LoBAL Quasar SDSS J085053.12+445122.5: I. Spectral Synthesis Analysis Reveals a Massive Outflow
• Probing the Nature of High Redshift Weak Emission Line Quasars: A Young Quasar with a Starburst Host Galaxy
• Multi-Epoch Observations of Extremely High-Velocity Emergent Broad Absorption
• X-ray spectral variability in PG1535+547: the changing-look of a 'soft X-ray weak' AGN
• A large sample of Kohonen-selected SDSS quasars with weak emission lines: selection effects and statistical properties
• The Sloan Digital Sky Survey Reverberation Mapping Project: the CIV Blueshift, Its Variability, and Its Dependence Upon Quasar Properties
• Anomalously Steep Reddening Law in Quasars: An Exceptional Example Observed in IRAS14026+4341
• Supermassive Black-Hole Growth Over Cosmic Time: Active Galaxy Demography, Physics, and Ecology from Chandra Surveys
• Fe II Emission in AGN: The Role of Total and Gas-Phase Iron Abundance
• Steep Hard-X-ray Spectra Indicate Extremely High Accretion Rates in Weak Emission-Line Quasars
• The Ultraviolet-to-Mid-Infrared Spectral Energy Distribution of Weak Emission Line Quasars
• A long hard look at the minimum state of PG 2112+059 with XMM-Newton
• PHL 1092 as a transient extreme X-ray weak quasar
• Strong UV and X-ray variability of the Narrow Line Seyfert 1 Galaxy WPVS 007 -- on the nature of the X-ray low state
• NuSTAR Observations of Intrinsically X-ray Weak Quasar Candidates: An Obscuration-Only Scenario
• Intranight Optical Variability of Radio-Quiet Weak Emission Line Quasars-III
• The environment of weak emission-line quasars
• On the Emergence of Thousands of Absorption Lines in the Quasar PG1411+442: A Clumpy High-Column Density Outflow from the Broad Emission-Line Region?
• The Binary Black Hole Model for Mrk 231 Bites the Dust
• The Frequency of Intrinsic X-ray Weakness Among Broad Absorption Line Quasars
• The Extreme Super-Eddington NLS1 RX J0134.2-4258 -- II. A Weak-Line Seyfert Linking to the Weak-Line Quasar
• The z=0.54 LoBAL Quasar SDSS J085053.12+445122.5: II. The Nature of Partial Covering in the Broad-Absorption-Line Outflow
• The Properties of Low-Redshift FeLoBAL Quasars: III. The Location and Geometry of the Outflows
• The most luminous blue quasars at 3.0<z<3.3. II. CIV/X-ray emission and accretion disc physics
• Intranight Optical Variability of Radio-Quiet Weak Emission Line Quasars
• Connecting Low- and High-Redshift Weak Emission-Line Quasars via HST Spectroscopy of Ly$\alpha$ Emission
• Exploratory Chandra observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.30
• The X-ray Properties of Million Solar Mass Black Holes
• XMM-Newton observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.326
• Shedding New Light on Weak Emission-Line Quasars in the C${}_{\mathrm{IV}}$-H$\beta$ Parameter Space
• Strong and Rapid X-ray Variability of the Super-Eddington Accreting Quasar SDSS J081456.10+532533.5
• Black hole masses of weak emission line quasars based on continuum fit method
• Ultraviolet emission lines of Si II in quasars --- investigating the "Si II disaster"
• Composite spectra of quasars with different UV spectral index
• Insights into Quasar UV Spectra Using Unsupervised Clustering Analysis
• Optical monitoring of the z=4.40 quasar Q 2203+292
• Evidence of under-developed torus and broad-line region of weak emission line quasars based on their spectral energy distribution
• Radio Scrutiny of the X-ray-Weak Tail of Low-Mass Active Galactic Nuclei: A Novel Signature of High-Eddington Accretion?
• XMM-Newton, Swift and ROSAT observations of LBQS 0102-2713
• Rarefied Broad-Line Regions in Active Galactic Nuclei: Anomalous Responses in Reverberation Mapping and Implications for Weak Emission-Line Quasars
• Shedding the envelope: JWST reveals a kiloparsec-scale [OIII]-weak Balmer shell around a z=7.64 quasar
• The unusual spectral energy distribution of LBQS 0102-2713
• Strong X-ray Variability of I Zwicky 1: Obscuration from Clumpy Accretion-Disk Winds