Studies of stationary features in jets: BL Lacertae - II. Trajectory reversals and superluminal speeds on sub-parsec scales

Open Access

Table 1.

Characteristics of reverse motion.

Reversals				Combo reversals
	Type	Epoch	cw/		Type	Epoch	cw/
		(yr)	ccw			(yr)	ccw
1	R	1999.41	cw
2	RL	2001.50	cw
3	R	2002.52	cw
4	R	2002.60	ccw	1	RC	2002.81 ^(c)	ccw
5	R	2002.81	ccw
6	RA ^(a)	–	ccw
7	R	2008.48	cw
8	R	2009.73	cw
9	RL	2010.65	cw	2	RO	2011.14 ^(d)	cw
10	R	2011.14	cw
11	R	2012.48	ccw
12	R	2013.61	cw
13	R	2013.64	cw	3	RC	2013.61 ^(c)	cw
14	R	2013.96	ccw
15	R	2014.66	cw
16	R	2015.46	cw
17	R	2016.42	cw
18	RA	2016.85 ^(b)	ccw
19	R	2017.31	cw
20	RL	2018.31	ccw
21	R	2018.52	ccw	4	RO	2018.31 ^(d)	ccw
22	R	2018.86	ccw

Notes. Two main columns separate the characteristics of reversals and combination of reversals. The columns for reversals are as follows: Reversal type and direction of reverse motion. The columns for the combination of reversals are the type, epoch, and direction of reverse motion.

^(a)

The type of reversal is questionable because of the proximity of the smoothed trajectory to the gap in the observational data.

^(b)

The epoch 2016.85 (blue circle in Fig. 5) of the C7 position at the maximum distance from the starting position of the reversal at epoch 2016.61 (see Fig. 5 and Table 2) is taken as the epoch of the turning point for the RA-type reversal.

^(c)

The epoch of the C7 position at the maximum distance from the starting position of the reversal (see Table 2) is taken as the epoch of the turning point for the RC-type reversal.

^(d)

The epoch of the turning point of the quasi-oscillatory reversal is taken as the epoch of the top of the reversal, which is closest to the epoch corresponding to t_s + (t_e − t_s)/2.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.