Examples of AGN Variability


Longterm
OJ 287

AO 0235+164

B2 1215+303

B2 1308+326

PG 0804+762

PG 1001+054

PG 1626+554

PG 1704+608

PKS 0754+100

 

Intraday

BL Lac

PKS 0735+178

S5 0716+714

 

Microvariability

Mrk 421

Mrk 501

 

References

 


Longterm Variability

 

OJ 287

This is one of the most extensively studied blazars. Photographic objervations extend back into the late 1800s. Superimposed on slow undulating variations lasting several decades, there are rapid outbursts of 4 magnitudes or more. There is some weak indication of periodicity for the outbursts with an 11 year cycle. The outbursts themselves often appear double. It has been suggested that the central supermassive blackhole driving the activity may be a binary. Takalo and Sillanpaa (1999)

 

AO 0235+164

The B light curve for AO 0235+164 in terms of the modified JD. This is an extensively studied object which exhibits short-term outbursts and declines. Fan and Lin (2000)

 

 

B2 1215+303 (ON 325)

The B light curve for B2 1215+303 with respect to the modified JD. This object appears to be mostly in a "high" state that is occasionally interrupted by episodes of generally lower activity. Fan and Lin (2000)

 

 

B2 1308+326 (OP 313)

The B light curve for B2 1308+326 with respect to the modified JD. This source seems to exhibit primarily short-term outbursts. Fan and Lin (2000)

 

 

PG 0804+762

The R (filled) and B (open) lightcurves for PG 0804+762 over a period of approximately 7 years. The horizontal axis is in days. This source does not seem to exhibit violent outbursts or declines, but merely slow, irregular variations. Giveon et al. (1999)

 

 

PG 1001+054

The R (filled) and B (open) lightcurves for PG 1001+054 over a period of approximately 7 years. The horizontal axis is in days. This source does not seem to exhibit violent outbursts or declines. This sources was undergoing a slow decline that was interrupted by a modest outburst that lasted for approximately 600 days. Giveon et al. (1999)

 

 

 

PG 1626+554

The R (filled) and B (open) lightcurves for PG 1626+554 over a period of approximately 7 years. The horizontal axis is in days. This source does not seem to exhibit violent outbursts or declines. This source exhibited a modest, but steady rise throughout this interval. Giveon et al. (1999)

 

 

PG 1704+608

The R (filled) and B (open) lightcurves for PG 1704+608 over a period of approximately 7 years. The horizontal axis is in days. This source does not seem to exhibit violent outbursts or declines. This source exhibited only an extremely modest decline over this interval of time... except for the last observation which seems to indicate that a modest outburst had taken place. Giveon et al. (1999)

 

 

PKS 0754+100 (OI 090.4)

The B light curve for PKS 0754+100 with respect to the modified JD. This source exhibits moderate, irregular fluctuations of about 1 magnitude that seem to last less than a year. Occasional large, longer declines can approach 2 magnitudes. Fan and Lin (2000)

 

 

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Intraday Variability

 

 

BL Lac

The V light curve for BL Lac over a period of about 1 year. In addition to the slow irregular variation of 2 magnitudes over this period, irregular outbursts and declines of more than 1 magnitude can be seen to occur over periods of several days. Tosti et al. (1999)

 

 

PKS 0735+178

The R lightcurve fpr PKS 0735+178 over a period of about 6 years. During periods of coverage, significant variation of nearly 2 magnitudes can be seen over periods of several months. Significant variations over several days are clearly evident in the data. Tosti et al. (1999)

 

 

S5 0716+714

This light curve corresponds to almost 6 years of surveillance. This source has a high enough declination that it can be observed nearly year round from many northern hemisphere locations. This source exhibits slow irregular variations on which are superimposed outbursts of various intensities. Outbursts of 1 magnitude seem to reoccur about once every 2 years and last about 3 months. The one 2 magnitude outburst that was recorded lasted nearly 6 months. This source is a gamma-ray loud source. Massaro et al. (1999)

 

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Microvariability

 

 

BL Lac

The R light curve for BL Lac over a period of about 6 hours. The total range of variation is nearly 0.5 magnitude. During one episode the source systematically brightened 0.4 magnitude in about 1 hour. During this night of observations at least three mini-outbursts were detected. Tosti et al. (1999)

 

 

Mrk 421

The magnitude variation (unspecified band) for Mrk 421 on 13 March 1981. The x-axis is the UT in hours (200 = 2h UT). Superimposed on a slow decline, three irregular mini-outbursts of about 0.1 magnitude were recorded. Mrk 421 has been detected as a source of TeV gamma-rays. Miller et al. (1999)

 

 

Mrk 501

The magnitude variation (unspecified band) for Mrk 501 on 5 June 1998. The x-axis is in days and covers approximately 3 hours. The average level remained constant during this interval, but a 0.1 magnitude mini-outburst was recorded that lasted approximately one hour. A second mini-outburst had apparently begun near the end of the observations. Mrk 501 has been detected as a source of TeV gamma-rays. Miller et al. (1999)

 

 

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References

 

Takalo, L. O. and Sillanpaa, A., BL Lac Phenomenon, ASP Conference Series volume 159 (1999) The illustration is on the cover of this book.

Miller , H. R. et al., BL Lac Phenomenon, ASP Conference Series, volume 159, 75 (1999)

Massaro, E. et al., BL Lac Phenomenon, ASP Conference Series, volume 159, 139 (1999)

Tosti, G. et al., BL Lac Phenomenon, ASP Conference Series volume 159 (1999)

Giveon, U. et al. Mon. Not. R. Astron. Soc. 306, 637 (1999)

Fan, J. H. and Lin, R. G. The Astrophysical Journal 537, 101 (2000)

 

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ggs
June 2001