J/MNRAS/440/799 Low Ionization BALQSOs MgII and AlIII variability (Vivek+, 2014) ================================================================================ Variability in Low Ionization Broad Absorption Line outflows. Vivek M., Srianand R., Petitjean P., Mohan V., Mahabal A., Samui S. =2014MNRAS.440..799V ================================================================================ ADC_Keywords: QSOs ; Spectroscopy Keywords: galaxies: active - quasars: absorption lines - quasars: general Abstract: We present results of our time variability studies of MgII and AlIII absorption lines in a sample of 22 Low Ionization Broad Absorption Line QSOs (LoBAL QSOs) at 0.2<=z_em_<=2.1 using the 2-m telescope at IUCAA Girawali Observatory over a time-scale of 10d to 7.69years in the QSO's rest frame. Spectra are analysed in conjunction with photometric light curves from Catalina Real-Time Transient Survey. Long time-scale (i.e. >=1-year) absorption line variability is seen in eight cases (36 per cent systems) while only four of them (i.e. 18 per cent systems) show variability over short time-scales (i.e. <1-year). We notice a tendency of highly variable LoBAL QSOs to have high ejection velocity, low equivalent width and low redshift. The detection rate of variability in LoBAL QSOs showing Fe fine-structure lines (FeLoBAL QSOs) is less than that seen in non-Fe LoBAL QSOs. Absorption line variability is more frequently detected in QSOs having continuum dominated by Fe emission lines compared to rest of the QSOs. Confirming these trends with a bigger sample will give vital clues for understanding the physical distinction between different BAL QSO sub-classes. We correlate the absorption line variability with various parameters derived from continuum light curves and find no clear correlation between continuum flux and absorption line variabilities. However, sources with large absorption line variability also show large variability in their light curves. We also see appearance/disappearance of absorption components in two cases and clear indications for profile variations in four cases. The observed variability can be best explained by a combination of process driven by continuum variations and clouds transiting across the line of sight. Description: Our LoBAL QSO sample consists of 22 QSOs brighter than i=17.5mag that are accessible from IUCAA Girawali Observatory (IGO). Five of these sources show broad FeII absorption in the resonance lines and in the excited fine-structure lines. All the new observations presented here were carried out using the 2-m telescope at IUCAA Girawali Observatory (IGO). The spectra were obtained using the IUCAA Faint Object Spectrograph (IFOSC). We have been observing the sample from the year 2006 with the aim of studying the time variability in the BALs over a range of time-scales. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 110 22 Source parameters measured from the data table1.dat 83 105 Log of observations table4.dat 80 131 Equivalent width measurements -------------------------------------------------------------------------------- See also: J/ApJ/698/1095 : The FIRST-2MASS red QSO survey. II. (Urrutia+, 2009) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 A19 --- SDSS QSO SDSS name (JHHMMSS.ss+DDMMSS.s) 21- 30 A10 --- SName Short name (JHHMM+DDMM) 31- 32 A2 -- n_SName [+* ] Fe emission (1) 34- 38 F5.3 --- zem [0.5/2.0] Emission redshift (2) 40- 44 F5.3 --- zabs [0.5/2.0] Absorption redshift (3) 46- 52 F7.1 km/s Vmax [1865/20747] Maximum velocity (4) 54- 58 F5.2 0.1nm [3/33]?=- Average MgII equivalent width 59 A1 --- n_ [a] a corresponds to average AlIII equivalent width in 61- 67 E7.2 10-7W Lbol Bolometric luminosity (5) 69- 75 E7.2 Msun Mbh Black hole mass (derived from Lbol assuming Eddington accretion) 77- 81 F5.2 mag Dm ?=- Median variability {Delta}m value 83- 86 F4.2 mag e_Dm ?=- standard deviation of Dm 88- 93 F6.3 mag/yr Slope ?=- Slope of {Delta}m/{Delta}t graph 95- 99 F5.3 mag/yr e_Slope ? rms uncertainty on Slope 101-110 A10 --- Line Absorption line(s) probed in this study -------------------------------------------------------------------------------- Note (1): Note as follows: + = FeLoBAL QSO source (showing fine-structure Fe lines) * = source with strong Fe emission Note (2): zem is obtained from the fitting of SDSS composite. Note (3): zabs corresponds to the maximum optical depth. Note (4): Vmax is calculated for the MgII line from the normalized SDSS spectra. Vmax is identified as the maximum velocity at which source flux matches with the continuum. Note (5): Lbol is computed using the prescription, Lbol=7.9x{nu}F_{nu}B_, of Marconi et al. (2004MNRAS.351..169M). -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 A19 --- SDSS QSO SDSS name (JHHMMSS.ss+DDMMSS.s) 21- 30 A10 --- SName Short name 32- 42 A11 --- Inst Observatory/Instrument (2) 45- 54 A10 "date" Date Observation date 56- 60 I5 d MJD Modified Julian date 62- 63 I2 min Exp1 [5/80] Exposure time of 1 exposure 64 A1 --- --- [x] 65 I1 --- Nexp Number of exposures 67- 70 I4 0.1nm lam.min Lower value of wavelength coverage 71 A1 --- --- [-] 72- 76 I5 0.1nm lam.max Upper value of wavelength coverage 78- 80 I3 km/s Res Resolution 82- 83 I2 --- S/N [2/62] Signal-to-noise ratio (1) -------------------------------------------------------------------------------- Note (1): values quoted are mean of S/N calculated per pixel over the wavelength range 5800{AA}-6200{AA}. Note (2): IGO = IUCAA Girawali Observatory -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- --- [SDSS] 6- 15 A10 --- SName Short name 17- 27 A11 --- n_SName Note on component 29- 33 A5 --- Ion Ion 35- 41 A7 --- Epoch Epoch identification (1) 44- 48 I5 d MJD ?=- Modified Julian date 50- 55 F6.1 0.1nm lam.min Lower value of wavelength range 56 A1 --- --- [-] 57- 62 F6.1 0.1nm lam.max Upper value of wavelength range 64- 67 F4.1 0.1nm Wrest Rest-frame equivalent width 69- 71 F3.1 0.1nm e_Wrest rms uncertainty on Wrest 73- 80 A8 --- Comment "Variable" -------------------------------------------------------------------------------- Note (1): 7 and 1 in the parenthesis refer to IFOSC 7 and IFORS 1 data, respectively. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 21-Jan-2015