QSO Absorption Lines from QSOs

Abstract

We present the results of a search for metal absorption lines in the spectra of background QSOs whose sightlines pass close to foreground QSOs. We detect MgII(2796,2803) absorption in Sloan Digital Sky Survey (SDSS) spectra of four z>1.5 QSOs whose lines of sight pass within 26-98 kpc of lower redshift (z~0.5-1.5) QSOs. The 100% [4/4 pairs] detection of MgII in the background QSOs is clearly at odds with the incidence of associated (z_abs ~ z_em) systems -- absorbers which exist towards only a few percent of QSOs. Although the quality of our foreground QSO spectra is not as high as the SDSS data, absorption seen towards one of the background QSOs clearly does not show up at the same strength in the spectrum of the corresponding foreground QSO. This implies that the absorbing gas is distributed inhomogeneously around the QSO, presumably as a direct consequence of the anisotropic emission from the central AGN. We discuss possible origins for the MgII lines, including: absorption by gas from the foreground QSO host galaxy; companion galaxies fuelling the QSO through gravitational interactions; and tidal debris left by galaxy mergers or interactions which initiated the QSO activity. No single explanation is entirely satisfactory, and we may well be seeing a mixture of phenomena.

Accepted for publication in ApJ Letters. 5 pages

References in corpus (3)

• The host galaxies of luminous quasars
• The Small-Scale Environment of Quasars
• High Metallicity, Photoionised Gas in Intergalactic Large-Scale Filaments

Cited by in corpus (51)

• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• Quasars Probing Quasars I: Optically Thick Absorbers Near Luminous Quasars
• The Sloan Digital Sky Survey Quasar Lens Search. V. Final Catalog from the Seventh Data Release
• Quasars Probing Quasars VI. Excess HI Absorption Within One Proper Mpc of z~2 Quasars
• Quasars Probing Quasars II: The Anisotropic Clustering of Optically Thick Absorbers around Quasars
• Photometric redshifts and quasar probabilities from a single, data-driven generative model
• Optical properties and spatial distribution of MgII absorbers from SDSS image stacking
• Quasars Probing Quasars III: New Clues to Feedback, Quenching, and the Physics of Massive Galaxy Formation
• Quasars Probing Quasars VII. The Pinnacle of the Cool Circumgalactic Medium Surrounds Massive z~2 Galaxies
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• Quasars Probing Quasars IV: Joint Constraints on the Circumgalactic Medium from Absorption and Emission
• Narrow associated QSO absorbers: clustering, outflows and the line-of-sight proximity effect
• Lensing, reddening and extinction effects of MgII absorbers from z=0.4 to z=2
• MUSE Analysis of Gas around Galaxies (MAGG) -- III: The gas and galaxy environment of z = 3-4.5 quasars
• Quasars Probing Quasars VIII. The Physical Properties of the Cool Circumgalactic Medium Surrounding z ~ 2-3 Massive Galaxies Hosting Quasars
• Detection of the Transverse Proximity Effect: Radiative Feedback from Bright QSOs
• The nature of proximate damped Lyman alpha systems
• The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 Myr
• The Pittsburgh Sloan Digital Sky Survey MgII Quasar Absorption-Line Survey Catalog
• The Stacked Lyman-Alpha Emission Profile from the Circum-Galactic Medium of z~2 Quasars
• Mapping the Lyman-Alpha Emission Around a z~6.6 QSO with MUSE: Extended Emission and a Companion at Close Separation
• The incidence of cool gas in ~ 1e13 Msun halos
• On the origin of excess cool gas in quasar host halos
• Galaxy and Quasar Fueling Caught in the Act from the Intragroup to the Interstellar Medium
• A Deep Narrowband Imaging Search for CIV and He II Emission from Ly$\alpha$ Blobs
• The Sloan Digital Sky Survey Quasar Lens Search. IV. Statistical Lens Sample from the Fifth Data Release
• Average Properties of a Large Sample of z_abs ~ z_em associated Mg II Absorption Line Systems
• The MgII Cross-section of Luminous Red Galaxies
• The extent of the MgII absorbing circum-galactic medium of quasars
• On the cool gaseous haloes of quasars
• Testing the Evolutionary Link between Type 1 and Type 2 Quasars with Measurements of the Interstellar Medium
• Quasar Sightline and Galaxy Evolution (QSAGE) Survey - I. The Galaxy Environment of OVI Absorbers up to z=1.4 around PKS 0232-04
• On the Connection Between Metal Absorbers and Quasar Nebulae
• Cool circumgalactic gas of passive galaxies from cosmological inflow
• Metal Absorption Systems in Spectra of Pairs of QSOs
• Simba: The average properties of the circumgalactic medium of $2\le z\le 3$ quasars are determined primarily by stellar feedback
• The COS-AGN survey: Revealing the nature of circum-galactic gas around hosts of active galactic nuclei
• A Fundamental Test for Galaxy Formation Models: Matching the Lyman-$\alpha$ Absorption Profiles of Galactic Halos over Three Decades in Distance
• Galaxies with Background QSOs, I: A Search for Strong Galactic H-alpha Lines
• The correlated variations of C IV narrow absorption lines and quasar continuum
• Hunting for Metals Using XQ-100 Legacy Survey Composite Spectra
• Probing the environment of high-z quasars using the proximity effect in projected quasar pairs
• Observations of the Gas Reservoir around a Star Forming Galaxy in the Early Universe
• MUSE view of PDS 456: kpc-scale wind, extended ionized gas and close environment
• Astrophysics in 2006
• The Study of Circumgalactic Medium with Quasar Pairs
• The Circumgalactic Medium in Massive Halos
• A new apparent quasar pair: Q2225-403A,B
• Probing the circumgalactic medium of active galactic nuclei with background quasars
• Environment or Outflows? New insight into the origin of narrow associated QSO absorbers
• Circumgalactic medium of quasar host galaxies at 0.4<z<0.8 probed by strong Mg II absorption