Optical Spectroscopy of SDSS J004054.65-0915268: Three Possible Scenarios for the Classification. A z ̃ 5 BL Lacertae, a Blue FSRQ, or a Weak Emission Line Quasar

Journal
Date Issued
2016
Author(s)
•
•
•
•
•
DOI
Abstract
The haunt of high-redshift BL Lacerate objects is day by day more compelling to firmly understand their intrinsic nature and evolution. SDSS J004054.65-0915268 is, at the moment, one of the most distant BL Lac candidates, at z ̃ 5. We present a new optical-near-IR spectrum obtained with ALFOSC-NOT with a new, custom designed dispersive grating aimed to detect broad emission lines that could disprove this classification. In the obtained spectra, we do not detect any emission features and we provide an upper limit to the luminosity of the C IV broad emission line. Therefore, the nature of the object is then discussed, building the overall spectral energy distribution (SED) and fitting it with three different models. Our fits, based on SED modeling with different possible scenarios, cannot rule out the possibility that this source is indeed a BL Lac object, though the absence of optical variability and the lack of strong radio flux seem to suggest that the observed optical emission originates from a thermalized accretion disk.
Volume
151
Issue
2
Start page
35
Uri
Url
Issn Identifier
0004-6256
Ads BibCode
2016AJ....151...35L
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Landoni_2016_AJ_151_35.pdf

Description
Pdf editoriale
Size

787.58 KB

Format

Adobe PDF

Checksum (MD5)

07098b629195fdc9976d3844572f6f2c