Optical Spectroscopic Observations of Gamma-ray Blazar Candidates. V. TNG, KPNO, and OAN Observations of Blazar Candidates of Uncertain Type in the Northern Hemisphere

Abstract

The extragalactic $\gamma$-ray sky is dominated by emission from blazars, a peculiar class of active galactic nuclei (AGNs). Many of the $\gamma$-ray sources included in Fermi -Large Area Telescope Third Source catalog (3FGL) are classified as a blazar candidate of uncertain type (BCU) because there is no optical spectra available in the literature to confirm their nature. In 2013 we started a spectroscopic campaign to look for the optical counterparts of the BCUs and of the Unidentified $\gamma$-ray Sources. The main goal of our investigation is to confirm the blazar nature of these sources having peculiar properties as compact radio emission and/or selected on the basis of their infrared (IR) colors. Whenever possible we also determine their redshifts. Here we present the results of the observations carried out in the Northern hemisphere in 2013 and 2014 at Telescopio Nazionale Galilleo (TNG), Kitt Peak National Observatory (KPNO) and Observatorio Astronómico Nacional (OAN) in San Pedro Mártir. In this paper we describe the optical spectra of 25 sources. We confirmed that all the 15 BCUs observed in our campaign and included in our sample are blazars and we estimated the redshift for 3 of them. In addition, we present the spectra for 3 sources classified as BL Lacs in the literature but with no optical spectra available to date. We found that one of them is a quasar (QSO) at a redshift $z$ = 0.208 and the other 2 are BL Lacs. Moreover, we also present 7 new spectra for known blazars listed in the Roma-BZCAT having an uncertain redshift or being classified as BL Lac candidates. We found that one of them, 5BZB J0724+2621 is a `changing look' blazar. According to the spectrum available in the literature it was classified as a BL Lac but in our observation we clearly detected a broad emission line that lead to classify this source as a QSO at $z$=1.17.

arXiv comment21 pages, 26 figures, 3 tables, pre-proof version, published on the Astronomical Journal. arXiv admin note: text overlap with arXiv:1503.04202

References in corpus (63)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
• Fermi Large Area Telescope Second Source Catalog
• Fermi Large Area Telescope First Source Catalog
• The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Chandra Source Catalog
• The 6dF Galaxy Survey: Samples, Observational Techniques and the First Data Release
• TeV Gamma Rays from BL Lac Objects due to Synchrotron Radiation of Extremely High Energy Protons
• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• The VLA Low-frequency Sky Survey
• Roma-BZCAT: A multifrequency catalogue of Blazars
• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. V. Multi-epoch VLBA Images
• The FIRST Bright Quasar Survey. II. 60 Nights and 1200 Spectra Later
• The first XMM-Newton slew survey catalogue: XMMSL1
• A simplified view of blazars: clearing the fog around long-standing selection effects
• Spectroscopy of The Largest Ever Gamma-ray Selected BL Lac Sample
• MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VIII. Faraday rotation in parsec-scale AGN jets
• The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation
• Limits on Cosmological Models From Radio-Selected Gravitational Lenses
• Identification of the infrared non-thermal emission in Blazars
• 1SXPS: A deep Swift X-ray Telescope point source catalog with light curves and spectra
• A Sample-oriented Catalogue of BL Lacertae Objects
• Swift X-ray Telescope Monitoring of Fermi-LAT Gamma Ray Sources of Interest
• MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. XI. Spectral distributions
• An Optical View of BL Lacertae Objects
• The WISE Blazar-Like Radio-Loud Sources: An All-Sky Catalog Of Candidate Gamma-Ray Blazars
• A Statistical Approach to Recognizing Source Classes for Unassociated Sources in the First Fermi-LAT Catalog
• Infrared Colors of the gamma-ray detected blazars
• A simplified view of blazars: the gamma-ray case
• Unveiling the nature of the unidentified gamma-ray sources I: a new method for the association of gamma-ray blazars
• Parsec-Scale Blazar Monitoring: Flux and Polarization Variability
• Fermi's Sibyl: Mining the gamma-ray sky for dark matter subhaloes
• Stringent Constraints On The Dark Matter Annihilation Cross Section From Subhalo Searches With The Fermi Gamma-Ray Space Telescope
• Optical spectroscopic observations of gamma-ray blazars candidates I: preliminary results
• The First Simultaneous 3.5 and 1.3mm Polarimetric Survey of Active Galactic Nuclei in the Northern Sky
• Australia Telescope Compact Array observations of Fermi unassociated sources
• Unveiling the nature of the unidentified gamma-ray sources II: radio, infrared and optical counterparts of the gamma-ray blazar candidates
• Optical spectroscopic observations of blazars and gamma-ray blazar candidates in the Sloan Digital Sky Survey Data Release Nine
• Identification of the Early Fermi LAT Gamma-Ray Bright Objects with Extragalactic VLBI sources
• Unveiling the nature of the unidentified gamma-ray sources III: gamma-ray blazar-like counterparts at low radio frequencies
• Unveiling the nature of the unidentified gamma-ray sources IV: the $\text{Swift}$ catalog of potential X-ray counterparts
• Optical spectroscopic observations of gamma-ray blazar candidates II. The 2013 KPNO campaign in the Northern Hemisphere
• New Associations of Gamma-Ray Sources from the Fermi Second Source Catalog
• Unidentifed gamma-ray sources: hunting gamma-ray blazars
• Optical spectroscopic observations of gamma-ray blazar candidates III. The 2013/2014 campaign in the Southern Hemisphere
• Blue Fermi Flat Spectrum Radio Quasars
• Gamma-Ray Active Galactic Nucleus Type through Machine-Learning Algorithms
• Optical spectroscopic observations of gamma-ray blazar candidates IV. Results of the 2014 follow-up campaign
• Search for gamma-ray-emitting active galactic nuclei in the Fermi-LAT unassociated sample using machine learning
• Unveiling the nature of the unidentified gamma-ray sources V: analysis of the radio candidates with the kernel density estimation
• Refining the associations of the Fermi Large Area Telescope Source Catalogs
• Characteristics of EGRET Blazars in the VLBA Imaging and Polarimetry Survey (VIPS)
• The colours of BL Lac objects: a new approach to their classification
• BL Lacertae identifications in a ROSAT-selected sample of Fermi unidentified objects
• The low-frequency radio catalog of flat spectrum sources
• The XMM-Newton slew survey in the 2-10 keV band
• Multiband Diagnostics of Unidentified 1FGL Sources with Suzaku and Swift X-ray Observations
• ESO VLT Optical Spectroscopy of BL Lac Objects IV. New spectra and properties of the full sample
• Searching for gamma-ray blazar candidates among the unidentified INTEGRAL sources
• The changing look of PKS 2149-306

Cited by in corpus (44)

• Fermi Large Area Telescope Fourth Source Catalog
• The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• 3FHL: The Third Catalog of Hard Fermi-LAT Sources
• The Central Engines of Fermi Blazars
• On the redshift of TeV BL Lac objects
• Two new catalogs of blazar candidates in the WISE infrared sky
• Optical spectroscopic observations of $\gamma$-ray blazar candidates VI. Further observations from TNG, WHT, OAN, SOAR and Magellan telescopes
• Blazar Flaring Patterns (B-FlaP): Classifying Blazar Candidates of Uncertain type in the third Fermi-LAT catalog by Artificial Neural Networks
• The Gamma-ray Blazar Quest: new optical spectra, state of art and future perspectives
• Optical spectroscopic survey of a sample of Unidentified Fermi objects
• The Infrared-Gamma-Ray Connection: A WISE View of the Extragalactic Gamma-Ray Sky
• Research and characterisation of blazar candidates among the Fermi/LAT 3FGL catalogue using multivariate classifications
• Optical Spectroscopic Observations of Gamma-Ray Blazar Candidates. VII. Follow-up Campaign in the Southern Hemisphere
• 3FGLzoo. Classifying 3FGL Unassociated Fermi-LAT Gamma-ray Sources by Artificial Neural Networks
• Optical archival spectra of blazar candidates of uncertain type in the 3${}^{rd}$ Fermi Large Area Telescope Catalog
• Optical spectroscopy of BL Lac objects: TeV candidates
• Optical spectroscopic observations of gamma-ray blazar candidates VIII: the 2016-2017 follow up campaign carried out at SPM, NOT, KPNO and SOAR telescopes
• An optical overview of blazars with LAMOST I: Hunting changing-look blazars and new redshift estimates
• Radio Weak BL Lac objects in the Fermi era
• Optical spectroscopy of Blazars for the Cherenkov Telescope Array
• The Changing Look Blazar B2 1420+32
• Classification of New X-ray Counterparts for Fermi Unassociated Gamma Ray Sources Using the Swift X-Ray Telescope
• A new method to unveil blazars among multi-wavelength counterparts of Unassociated Fermi gamma-ray Sources
• Optical spectroscopic observations of gamma-ray blazar candidates. IX. Optical archival spectra and further observations from SOAR and OAGH
• Identifying the 3FHL catalog: I. Results of the KOSMOS optical spectroscopy campaign
• Identifying the 3FHL catalog: CTIO results
• Optical characterization of WISE selected blazar candidates
• Optical spectroscopic observations of low-energy counterparts of Fermi-LAT gamma-ray sources
• The $\gamma$-ray sky seen at X-ray energies I. Searching for the connection between X-rays and $\gamma$-rays in Fermi BL Lac objects
• ZBLLAC -- A spectroscopic database of BL Lacertae objects
• The $\gamma$-ray sky seen at X-ray energies II: the Swift hunt of Fermi BL Lac objects among unidentified gamma-ray sources
• Optical Spectroscopy of Blazars for the Cherenkov Telescope Array -- II
• The Physical Properties of Changing-look Blazars
• Identifying the 3FHL catalog: V. Results of the CTIO-COSMOS optical spectroscopy campaign 2019
• Evaluating Optical Classification for {\em Fermi} Blazar Candidates with a Statistical method using Broadband Spectral Indices
• On the physical association of Fermi-LAT blazars with their low-energy counterparts
• The Fermi-LAT view of the changing-look blazar OQ 334
• A New Multi-Wavelength Census of Blazars
• Identifying the 3FHL Catalog. VI. Swift Observations of 3FHL Unassociated Objects with Source Classification via Machine Learning
• Powerful Radio Sources in the Southern Sky. I. Optical Identifications
• Relativistic plasmas in AGN jets - From synchrotron radiation to $\gamma$-ray emission
• Classifying blazar candidates from the 3FGL unassociated catalog into BL Lacs and FSRQs using Swift and WISE data
• Identifying the 3FHL catalog: VI. Results of the 2019 Gemini optical spectroscopy campaign
• An empirical "high-confidence" candidate zone for $Fermi$ BL Lacertae objects