J/MNRAS/449/2750 V and R lightcurves of BL Lac object PKS 0537-441 (Li+, 2015)
Colour variation of the BL Lacertae object PKS 0537-441.
Li X., Zhang L., Luo Y., Wang L., Zhou L.
<Mon. Not. R. Astron. Soc., 449, 2750-2758 (2015)>
=2015MNRAS.449.2750L 2015MNRAS.449.2750L (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Photometry, VRI ; Colors ; QSOs
Keywords: galaxies: active - BL Lacertae objects: general -
BL Lacertae objects: individual: PKS 0537-441 -
galaxies: fundamental parameters
Abstract:
We present the colour indices V-R of BL Lacertae object PKS 0537-441
on the basis of the photometric data monitored by the Rapid Eye
Mounting (REM) telescope located at the ESO Cerro La Silla observatory
(Chile). Nearly 700 quasi-simultaneous data groups were collected
during the period from 2004 to 2010. Our colour analysis shows the
existence of at least two variability mechanisms: one is the long-term
chromatic mechanism in which the variation traces a 0.04±0.01 slope
in the V-R versus V plot, the other is the chromatic mechanism
implying the spectral changes during the flares and on intraday
time-scales. A general bluer-when-brighter trend is confirmed in both
ascent and descent states during the flares and in the 2010 February
flare interval, while a much stronger bluer-when-brighter chromatism
is observed in both faint and bright states on intraday time-scales.
The discrete correlation function analysis reveals the existence of
a time-lag of 13+5.8-1.2 d between colour indices and magnitudes
during the period MJD 54404-54453, whereas no measurable time-lag
during other periods is found. Our results suggest that geometric
effects may be responsible for the long-term achromatic mechanism,
while the intrinsic shock-in-jet mechanism may produce the chromatic
variability during the flares and on intraday time-scales.
Description:
We have collected the long-term optical photometric data of PKS 0537-441
during the period 2004-2010 from the NIR/optical photometric data
collection presented by Impiombato et al. (2011, J/ApJS/192/12). These
data were obtained from the REM telescope located at the ESO Cerro La Silla
observatory (Chile). The telescope has a Ritchey-Chretien configuration
with a 60 cm f/2.2 primary and two stable Nasmyth f/8 focal stations.
By means of a dichroic placed before telescope focal plane, the
telescope simultaneously feeds two instruments: an NIR camera (REMIR;
see Tosti et al. 2004SPIE.5492..689T 2004SPIE.5492..689T) and an optical imaging camera
(ROSS; see Conconi et al. 2004SPIE.5492.1602C 2004SPIE.5492.1602C). The REMIR camera works
with a NIR(z', J, H and K) filter set and a Rockwell Hawaii I 512x512 CCD,
while the ROSS camera is equipped with a Johnson-Cousins VRI filters
and hosts a back-illuminated 1024x1024 Marconi 47-10 CCD.
Objects:
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RA (ICRS) DE Designation(s)
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05 38 50.36 -44 05 08.9 PKS 0537-441 = QSO B0537-441
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 683 The quasi-simultaneous magnitudes and
the corresponding colour index
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See also:
J/MNRAS/277/1477 : A catalogue of BL Lacertae objects (Padovani+ 1995)
J/ApJS/192/12 : Photometry of the blazar PKS 0537-441 (Impiombato+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.5 d MJD-V Modified Julian Date of the observation
in the V-band
13- 18 F6.3 mag Vmag Observed magnitude in the Johnson V-band
20- 24 F5.3 mag e_Vmag Uncertainty in Vmag
26- 36 F11.5 d MJD-R Modified Julian Date of the observation
in the R-band
38- 43 F6.3 mag Rmag Observed magnitude in the Cousins R-band
45- 49 F5.3 mag e_Rmag Uncertainty in Rmag
51- 56 F6.3 mag V-R Corresponding colour index V-R
58- 62 F5.3 mag e_V-R Uncertainty in V-R
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 11-Dec-2017