Damped Random Walk Parameters for Southern Sample: File Format

The reference for these variability parameters is MacLeod et al. 2010.

The following table describes the format of the data files s82drw_*.dat:

Field (Column)	Format	Units	Label	Explanations
1	I5	---	SDR5ID	Row of Schneider catalog (out of 77429) corresponding to that QSO (1)
2	F10.6	deg	ra	Median Right Ascension in decimal degrees (J2000)
3	F10.6	deg	dec	Median Declination in decimal degrees (J2000)
4	F6.4	---	redshift	Redshift
5	F7.3	mag	M_i	K-corrected absolute i band magnitude (9)
6	F7.3	log(M/Msun)	mass_BH(log(M/M_sun))	Black hole mass ('0.000' means none could be found) (2)
7	D	---	chi^2_pdf	χ2 per degree of freedom of damped random walk fit (2)
8	D	log days	log10(tau [days])	Best-fit damping time scale (τ) (3)
9	D	log[mag/sqrt(yr)]	log10(sigma [mag/sqrt(yr)])	Best-fit driving amplitude of short-term fluctuations (σ̂) (3) (4)
10	D	log days	log10(tau_lim_lo)	1-sigma lower limit on τ (Bayesian) (3)
11	D	log days	log10(tau_lim_hi)	1-sigma upper limit on τ (Bayesian) (3)
12	D	log[mag/sqrt(yr)]	log10(sig_lim_lo)	1-sigma lower limit on σ̂ (Bayesian) (3)
13	D	log[mag/sqrt(yr)]	log10(sig_lim_hi)	1-sigma upper limit on σ̂ (Bayesian) (3)
14	I1	---	edge	Edge flag: '1' if on edge of grid, '2' if too close to edge to properly centroid peak (5)
15	D	---	Plike	Log likelihood of damped random walk solution (ln LBest) (5)
16	D	---	Pnoise	Log likelihood of noise solution (ln LNoise) (5)
17	D	---	Pinf	Log likekihood of τ→∞ (ln L∞) (5)
18	D	mag	mu	Best-fit mean of light curve (μ)
19	I3	---	Npts	Number of light curve data points used in model (6)

Note (1): A value of '-1' indicates a newly confirmed DR7 quasar
Note (2): Taken from the Shen et al. (2008) catalog. A value of '-1' indicates a
newly confirmed DR7 quasar, and thus is not present in Shen et al.(2008)
(although it will likely be present in the latest catalog in Shen et al. 2011).
Note (3): If less than 10 observations, the value is set to '-10'. These objects should be rejected during analysis.
Note (4): Equivalent to σ̂ in Kozlowski et al. 2010, and σ [but in mag/sqrt(yr) rather than mag/sqrt(day)] in Kelly et al. 2009. Related to SF_∞ (the asymptotic value of the structure function) as SF_∞ = σ̂ * sqrt(τ).
Note (5): To ensure that the time scale and driving amplitude are well-constrained for the damped random walk fit, we suggest including only those objects with edge = 0, Plike-Pnoise > 2, and Plike-Pinf > 0.05, as in MacLeod et al. 2010.
Note (6): Only observations with 5<g≤30 mag and separated by at least 0.5 days from previous observation are accepted.
Note (9): For H_o = 70.0, {Omega}_M = 0.300, {Omega}_L = 0.700, {alpha}_Q = -0.50.

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