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Extremely Rapid, ~2 mag Brightening of the AGN 4C +40.01

PostPosted: Fri Oct 12, 2018 7:01 pm
by Michel Verlinden
ASASSN-18xx: Discovery of an Unprecedented, Extremely Rapid, ~2 mag Brightening of the AGN 4C +40.01

In ASAS-SN data, 4C +40.01 rapidly brightened to g~15.4 on UT 2018-10-12.19, while it was fainter than g~17.3 just a day before, UT 2018-10-11.17 (see its full ASAS-SN Sky Patrol light curve here). Such high brightness is unprecedented for this object, which is classified on NED as "Flat-Spectrum Radio Source" and "Seyfert 1.9".

This transient has been named "ASASSN-18xx" and has been posted to TNS ( ( In general, such behavior is very rarely seen for AGN or quasars (e.g, ATel #11110, #12082), so rapid multi-wavelength follow-up observations are strongly encouraged.

We would like to thank Las Cumbres Observatory and its staff for their continued support of ASAS-SN. ASAS-SN is funded in part by the Gordon and Betty Moore Foundation through grant GBMF5490 to the Ohio State University, NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of Sciences South America Center for Astronomy (CASSACA), and the Villum Fonden (Denmark).

Re: Extremely Rapid, ~2 mag Brightening of the AGN 4C +40.01

PostPosted: Wed Oct 17, 2018 11:55 am
by etienne bertrand
Pour avoir essayer de tenter cette cible hier, je ne l'ai pas observer même avec des poses de 40s bin3x3 dans la caméra de guidage... Il a dû regagner sa magnitude de 17.3...