Intra-night optical variability study of a non-jetted narrow-line Seyfert 1 galaxy: SDSS J163401.94+480940.1

TL;DR

This study reports the first intra-night optical variability detection in a non-jetted narrow-line Seyfert 1 galaxy, revealing a rapid flare suggesting relativistic jets, with implications for understanding jet formation in such galaxies.

Contribution

First characterization of intra-night optical variability in SDSS J163401.94+480940.2, revealing rapid flaring indicative of relativistic jets in a non-jetted NLSy1 galaxy.

Findings

Detected a rapid flare with a doubling time of ~22 minutes.

Indicated the possible presence of relativistic jets.

Discussed the non-detection of jets in VLBA observations.

Abstract

SDSS J163401.94$+$480940.2 is a non-jetted radio-loud narrow-line Seyfert 1 (NLSy1) galaxy. Optical monitoring of this object was carried out in two intra-night sessions each $\geq$ 3 hrs with 3.6m DOT. Intra-night optical variability (INOV) characterization is presented for the first time for this source. We have detected an unexpected remarkable flare in one of two monitoring sessions of SDSS J163401.94$+$480940.2, whose rapid brightening phase implied a minute like doubling time of $\sim$ 22 minutes, thereby approaching to the extremely fast minute like variability, observed from FSRQ PKS 1222$+$21 at 400 GeV. The detection of a minute-like variability suggests the existence of relativistic jets with a small viewing angle. We briefly discuss the possible mechanisms for the non-detection of relativistic jets in its Very Long Baseline Array (VLBA) observations.