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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 (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) and an optical imaging camera (ROSS; see Conconi et al. 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: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 05 38 50.36 -44 05 08.9 PKS 0537-441 = QSO B0537-441 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 62 683 The quasi-simultaneous magnitudes and the corresponding colour index
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
Bytes Format Units Label Explanations
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
History: From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 11-Dec-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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