A Hubble Space Telescope Imaging Study of Four FeLoBAL Quasar Host Galaxies

Abstract

We study the host galaxies of four Iron Low-Ionization Broad Absorption-line Quasars (FeLoBALs) using Hubble Space Telescope imaging data, investigating the possibility that they represent a transition between an obscured AGN and an ordinary optical quasar. In this scenario, the FeLoBALs represent the early stage of merger-triggered accretion, in which case their host galaxies are expected to show signs of an ongoing or recent merger. Using PSF subtraction techniques, we decompose the images into host galaxy and AGN components at rest-frame ultraviolet and optical wavelengths. The ultraviolet is sensitive to young stars, while the optical probes stellar mass. In the ultraviolet we image at the BAL absorption trough wavelengths so as to decrease the contrast between the quasar and host galaxy emission. We securely detect an extended source for two of the four FeLoBALs in the rest-frame optical; a third host galaxy is marginally detected. In the rest-frame UV we detect no host emission; this constrains the level of unobscured star formation. Thus, the host galaxies have observed properties that are consistent with those of non-BAL quasars with the same nuclear luminosity, i.e., quiescent or moderately starforming elliptical galaxies. However, we cannot exclude starbursting hosts that have the stellar UV emission obscured by modest amounts of dust reddening. Thus, our findings also allow the merger-induced young quasar scenario. For three objects, we identify possible close companion galaxies that may be gravitationally interacting with the quasar hosts.

33 pages, 15 figures. Accepted for publication in MNRAS

References in corpus (16)

• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• The bulk of the black hole growth since z~1 occurs in a secular universe: No major merger-AGN connection
• Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars
• Do the Most Massive Black Holes at $z=2$ Grow via Major Mergers?
• The rest-frame optical luminosity functions of galaxies at 2<z<3.5
• The Small-Scale Environment of Quasars
• Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars
• Decomposition of the Host Galaxies of Active Galactic Nuclei Using Hubble Space Telescope Images
• Star Formation in Luminous Quasars at 2<z<3
• The Accuracy of Morphological Decomposition of Active Galactic Nucleus Host Galaxies
• Near-Infrared Imaging of a z=6.42 Quasar Host Galaxy With the Hubble Space Telescope Wide Field Camera 3
• FERENGI: Redshifting galaxies from SDSS to GEMS, STAGES and COSMOS
• Host galaxies of bright high redshift quasars: Luminosities and colours
• Near-IR spectroscopy of luminous LoBAL quasars at 1<z<2.5
• Low redshift quasars in the SDSS Stripe 82. The local environments
• Constraining FeLoBAL outflows from absorption line variability

Cited by in corpus (5)

• The Physical Properties of Low Redshift FeLoBAL Quasars. I. Spectral Synthesis Analysis of the BAL Outflows using $SimBAL$
• The host galaxies of FeLoBAL quasars at z$\sim$0.9 are not dominated by recent major mergers
• The rapid transition from star-formation to AGN dominated rest-frame UV light at z ~ 4
• Using the Properties of Broad Absorption Line Quasars to Illuminate Quasar Structure
• The Nature of LoBAL QSOs: II. HST/WFC3 Observations Reveal Host Galaxies Dominated by Mergers