A Newborn AGN in a Starforming Galaxy

Abstract

We report on the finding of a newborn AGN, i.e. current AGN activity in a galaxy previously classified as non-active, and characterize its evolution. Black hole ignition event candidates were selected from a parent sample of spectrally classified non-active galaxies (2.394.312 objects), that currently show optical flux variability indicative of a type I AGN, according to the ALeRCE light curve classifier. A second epoch spectrum for a sample of candidate newborn AGN were obtained with the SOAR telescope to search for new AGN features. We present spectral results for the most convincing case of new AGN activity, for a galaxy with a previous star-forming optical classification, where the second epoch spectrum shows the appearance of prominent, broad Balmer lines without significant changes in the narrow line flux ratios. Long term optical lightcurves show a steady increase in luminosity starting 1.5 years after the SDSS spectrum was taken and continuing for at least 7 years. MIR colors from the WISE catalog have also evolved from typical non active galaxy colors to AGN-like colors and recent X-ray flux detections confirm its AGN nature.

Accepted for publication in A&A Letters

References in corpus (35)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Theoretical Modeling of Starburst Galaxies
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• The Host Galaxies and Classification of 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
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• First Results from the Catalina Real-time Transient Survey
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• The eROSITA X-ray telescope on SRG
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• An updated MILES stellar library and stellar population models
• Observational evidence for AGN feedback in early-type galaxies
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Dwarf Galaxies with Optical Signatures of Active Massive Black Holes
• Biases in Virial Black Hole Masses: An SDSS Perspective
• The SRG/eROSITA all-sky survey: First X-ray catalogues and data release of the western Galactic hemisphere
• The eROSITA Final Equatorial Depth Survey (eFEDS): The X-ray catalog
• Black hole variability and the star formation-AGN connection: Do all star-forming galaxies host an AGN?
• Universal bolometric corrections for AGN over 7 luminosity decades
• Accretion-Driven Evolution of Black Holes: Eddington Ratios, Duty Cycles, and Active Galaxy Fractions
• A universal ultraviolet-optical colour-colour-magnitude relation of galaxies
• The Automatic Learning for the Rapid Classification of Events (ALeRCE) Alert Broker
• Low redshift AGN in the Hamburg/ESO Survey: II. The active black hole mass function and the distribution function of Eddington ratios
• Alert Classification for the ALeRCE Broker System: The Light Curve Classifier
• Size and properties of the narrow-line region in Seyfert-2 galaxies from spatially-resolved optical spectroscopy
• The effect of nuclear gas distribution on the mass determination of supermassive black holes
• Multi-epoch Spectroscopy of Dwarf Galaxies with AGN Signatures: Identifying Sources with Persistent Broad H-alpha Emission
• Evolution in the Black Hole - Galaxy Scaling Relations and the Duty Cycle of Nuclear Activity in Star-Forming Galaxies
• RCSED - A Value-Added Reference Catalog of Spectral Energy Distributions of 800,299 Galaxies in 11 Ultraviolet, Optical, and Near-Infrared Bands: Morphologies, Colors, Ionized Gas and Stellar Populations Properties
• The QUEST-La Silla AGN variability survey: connection between AGN variability and black hole physical properties
• unTimely: a Full-sky, Time-Domain unWISE Catalog
• The final SDSS-IV/SPIDERS X-ray point source spectroscopic catalogue
• Discovery of Dying Active Galactic Nucleus in Arp 187: Experience of Drastic Luminosity Decline within $10^4$ years
• The Type 1 and Type 2 AGN dichotomy according to their ZTF optical variability
• Still alive and kicking: A significant outburst in changing-look AGN Mrk 1018

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