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J/ApJ/843/30  MgII line vs 3000Å continuum analysis in 68 QSOs  (Zhu+, 2017)

Relation between the variations in the MgIIλ2798 emission line and 3000Å continuum. Zhu D., Sun M., Wang T. <Astrophys. J., 843, 30 (2017)> =2017ApJ...843...30Z
ADC_Keywords: QSOs ; Spectra, optical ; Equivalent widths ; Redshifts Keywords: black hole physics; galaxies: active; quasars: emission lines; quasars: general ; surveys Abstract: We investigate the relationship between the MgIIλ2798 emission line and the 3000Å continuum variations using a sample of 68 intermediate-redshift (z∼0.65-1.50) broad-line quasars spanning a bolometric luminosity range of 44.49erg/s≤logLbol≤46.31erg/s (Eddington ratio from ∼0.026 to 0.862). This sample is constructed from SDSS-DR7Q and BOSS-DR12Q, each with at least two spectroscopic epochs in SDSS-I/II/III surveys. In addition, we adopt the following signal-to-noise ratio (S/N) selection criteria: (a) for MgII and the 3000Å continuum, S/N≥10; and (b) for narrow lines, S/N≥5. All our quasar spectra are recalibrated based on the assumption of constant narrow emission- line fluxes. In an analysis of spectrum-to-spectrum variations, we find a fairly close correlation (Spearman ρ=0.593) between the variations in broad MgII and in the continuum. This is consistent with the idea that MgII is varying in response to the continuum emission variations. Adopting the modified weighted least squares regression method, we statistically constrain the slopes (i.e., the responsivity α of the broad MgII) between the variations in both components for the sources in different luminosity bins after eliminating intrinsic biases introduced by the rescaling process itself. It is shown that the responsivity is quite small (average {bar}α∼0.464) and anti- correlates with the quasar luminosity. Our results indicate that high signal- to-noise flux measurements are required to robustly detect the intrinsic variability and the time lag of the MgII line. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 96 2420 *Sample data qsos.dat 24 69 List of unique quasars; table added by CDS
Note on table1.dat: Table 1 summarizes part of the final 1210 data pairs, consisting of 68 quasars that passed all the selection criteria and were used for the analysis of the spectroscopic variations in the MgIIλ2798 emission line and in the 3000Å continuum.
See also: II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007) VI/64 : Recombination line intensities for hydrogenic ions (Storey+, 1995) VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010) VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017) J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004) J/ApJ/633/638 : Variable quasar sample from SDSS (Wilhite+, 2005) J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006) J/ApJ/705/L76 : AGNs with double-peaked [OIII] lines (Wang+, 2009) J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010) J/ApJ/732/121 : V-band and Hβ monitoring of Z299-15 (Barth+, 2011) J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011) J/ApJ/755/60 : Reverberation mapping for 5 Seyfert 1 galaxies (Grier+, 2012) J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012) J/ApJ/818/30 : Lag measurements for z<0.8 QSOs from the SDSS-RM (Shen+, 2016) Byte-by-byte Description of file: qsos.dat
Bytes Format Units Label Explanations
1- 19 A19 --- SDSS SDSS object name ( 21- 24 F4.2 --- z [0.6/1.5] Improved quasar redshift from SDSS DR7Q and DR12Q (as in table 1)
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ID Identification number of our data pairs in this paper 6- 24 A19 --- SDSS SDSS object name ( 26- 29 I4 --- Plate SDSS Plate number 31- 34 I4 --- Fiber SDSS Fiber number 36- 40 I5 d MJD Modified Julian Date of observation 42- 47 F6.2 --- EW [18.4/195.5] Broad Mg II equivalent width (1) 49- 53 F5.2 [10-7W] logMg2 [36.8/42.5] log narrow MgII line luminosity (2) 55- 59 F5.2 [10-7W] logNe4 [0/42.3] log Ne IV (3426Å) line luminosity (2) 61- 65 F5.2 [10-7W] logO2 [40.4/45.1] log O II (3726, 3729Å) line luminosity (2) 67- 71 F5.2 [10-7W] logNe3 [40.4/42.4] log NeIII (3869Å) line luminosity (2) 73- 77 F5.2 [10-7W] logO3 [0/43.4] log OIII (5008Å) line luminosity (2) 79- 82 F4.2 --- z [0.6/1.5] Improved quasar redshift from DR7Q and DR12Q 84- 88 F5.2 [10-7W] log3000 [43.7/45.7] log 3000Å continuum luminosity (2) 90- 94 A5 --- Cat Quasar catalog observation is included in 96 I1 --- Nr [1/5] Number or narrow-lines used in final flux recalibration
Note (1): relative to the underlying continuum at 3000Å. Note (2): In units of erg/s.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 05-Feb-2018
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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