The spectra of IceCube neutrino candidate sources -- I. Optical spectroscopy of blazars

Abstract

There is mounting evidence that ultra-energetic neutrinos of astrophysical origin may be associated with blazars. Here we investigate a unique sample of 47 blazars, $\sim 20$ of which could be new neutrino sources. In particular, we focus on 17 objects of yet unknown redshift, for which we present optical spectroscopy secured at the Gran Telescopio Canarias and the ESO Very Large Telescope. We find all sources but one (a quasar) to be BL Lac objects. For nine targets we are able to determine the redshift (0.09~$<$~z~$<$~1.6), while for the others we set a lower limit on it, based on either the robust detection of intervening absorption systems or on an estimation derived from the absence of spectral signatures of the host galaxy. In some spectra we detect forbidden and semi-forbidden emission lines with luminosities in the range $10^{40}-10^{41}$ erg s${}^{-1}$. We also report on the spectroscopy of seven blazars possibly associated with energetic neutrinos that partially meet the criteria of our sample and are discussed in the Appendix. These results represent the starting point of our investigation into the real nature of these objects and their likelihood of being neutrino emitters.

arXiv comment18 pages, 4 figures, 9 Tables, Accepted for publication by MNRAS

References in corpus (44)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• Multi-messenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A
• Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert
• The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
• The Spectral Energy Distribution of Fermi bright blazars
• Automated data reduction workflows for astronomy
• Active Galactic Nuclei: what's in a name?
• The Connection between X-ray- and Radio-Selected BL Lacertae Objects
• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• The 5th edition of the Roma-BZCAT. A short presentation
• Near-infrared template spectra of normal galaxies: k-corrections, galaxy models and stellar populations
• Spectroscopy of The Largest Ever Gamma-ray Selected BL Lac Sample
• Imaging redshifts of BL Lac objects
• Photohadronic origin of $\gamma$-ray BL Lac emission: implications for IceCube neutrinos
• Dissecting the region around IceCube-170922A: the blazar TXS 0506+056 as the first cosmic neutrino source
• TXS 0506+056, the first cosmic neutrino source, is not a BL Lac
• The redshift of the BL Lac object TXS 0506+056
• Extreme blazars as counterparts of IceCube astrophysical neutrinos
• An Optical View of BL Lacertae Objects
• Dissecting the regions around IceCube high-energy neutrinos: growing evidence for the blazar connection
• ESO-VLT optical spectroscopy of BL Lac objects: II. New redshifts, featureless objects and classification assessments
• Progress in unveiling extreme particle acceleration in persistent astrophysical jets
• On the redshift of TeV BL Lac objects
• 3HSP J095507.9+355101: a flaring extreme blazar coincident in space and time with IceCube-200107A
• Optical spectroscopic observations of blazars and gamma-ray blazar candidates in the Sloan Digital Sky Survey Data Release Nine
• Optical spectroscopic observations of gamma-ray blazar candidates II. The 2013 KPNO campaign in the Northern Hemisphere
• Optical spectroscopic survey of a sample of Unidentified Fermi objects
• Optical Spectroscopic Observations of Gamma-Ray Blazar Candidates. VII. Follow-up Campaign in the Southern Hemisphere
• Neutrino emission from BL Lac objects: the role of radiatively inefficient accretion flows
• Comprehensive Multimessenger Modeling of the Extreme Blazar 3HSP J095507.9+355101 and Predictions for IceCube
• Optical spectroscopic survey of a sample of Unidentified Fermi objects: II
• The Parkes quarter-Jansky flat-spectrum sample 2. New Optical Spectra and Redshift Measurements
• Optical spectroscopy of BL Lac objects: TeV candidates
• Spectroscopy of 10 gamma-ray BL Lac objects at high redshift
• High redshift BL Lac objects: spectroscopy of candidates
• Spectroscopy of Optically Selected BL Lac Objects and their gamma-ray emission
• Optical spectroscopic observations of gamma-ray blazar candidates. X. Results from the 2018--2019 SOAR and OAN-SPM observations of blazar candidates of uncertain type
• AGILE detection of gamma-ray sources coincident with cosmic neutrino events
• New blazars from the cross-match of recent multi-frequency catalogs
• ZBLLAC -- A spectroscopic database of BL Lacertae objects
• The redshift and the host galaxy of the neutrino candidate 4FGL J0955.1+3551 (3HSP J095507.9+355101)
• Ongoing Star Formation in the BL Lacertae object PKS 2005-489

Cited by in corpus (5)

• The Spectra of IceCube Neutrino (SIN) candidate sources -- II. Source Characterisation
• The spectra of IceCube Neutrino (SIN) candidate sources -- III. Optical spectroscopy and source characterization of the full sample
• The Spectra of IceCube Neutrino (SIN) candidate sources -- V. Modeling and interpretation of multiwavelength and neutrino data
• The Spectra of IceCube Neutrino (SIN) candidate sources -- IV. Spectral energy distributions and multi-wavelength variability
• Search for the multiwavelength counterparts to extragalactic unassociated Fermi γ-ray sources