Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-02-19
Publ.Astron.Soc.Pac. 114 (2002) L587
Astronomy and Astrophysics
Astrophysics
14 pages, 5 figures, AASTEX 5.0.2, slight modifications following referee's report, PASP, in press
Scientific paper
10.1086/341687
The optically variable source SDSS J124602.54+011318.8 first appears in Sloan Digital Sky Survey (SDSS) data as a bright point source with nonstellar colors. Subsequent SDSS imaging and spectroscopy showed that the point source declined or disappeared, revealing an underlying host galaxy at redshift 0.385. Based on these properties, the source was suggested to be a candidate ``orphan afterglow'': a moderately beamed optical transient, associated with a gamma-ray burst (GRB) whose highly beamed radiation cone does not include our line of sight. We present new imaging and spectroscopic observations of this source. When combined with a careful re-analysis of archival optical and radio data, the observations prove that SDSS J124602.54+011318.8 is in fact an unusual radio-loud AGN, probably in the BL Lac class. The object displays strong photometric variability on time scales of weeks to years, including several bright flares, similar to the one initially reported. The SDSS observations are therefore almost certainly not related to a GRB. The optical spectrum of this object dramatically changes in correlation with its optical brightness. At the bright phase, weak, narrow oxygen emission lines and probably a broader H$\alpha$ line are superposed on a blue continuum. As the flux decreases, the spectrum becomes dominated by the host galaxy light, with emerging stellar absorption lines, while both the narrow and broad emission lines have larger equivalent widths. We briefly discuss the implications of this discovery on the study of AGNs and other optically variable or transient phenomena.
Chornock Ryan
Filippenko Alexei V.
Gal-Yam Avishay
Li Weidong
Ofek Eran O.
No associations
LandOfFree
SDSS J124602.54+011318.8: A Highly Variable AGN, Not an Orphan GRB Afterglow does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with SDSS J124602.54+011318.8: A Highly Variable AGN, Not an Orphan GRB Afterglow, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and SDSS J124602.54+011318.8: A Highly Variable AGN, Not an Orphan GRB Afterglow will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-303129