J/ApJ/754/38 MgII absorption systems for Flat-Spectrum Radio QSOs (Chand+, 2012)
Incidence of MgII absorption systems toward flat-spectrum radio quasars.
Chand H., Gopal-Krishna
<Astrophys. J., 754, 38 (2012)>
=2012ApJ...754...38C 2012ApJ...754...38C
ADC_Keywords: QSOs ; Equivalent widths ; Redshifts ; Spectroscopy ;
Radio sources
Keywords: BL Lacertae objects: general; galaxies: jets; intergalactic medium;
quasars: absorption lines; quasars: general; techniques: spectroscopic
Abstract:
The conventional wisdom that the rate of incidence of MgII absorption
systems, dN/dz (excluding "associated systems" having a velocity
βc relative to the active galactic nucleus (AGN) of less than
∼5000km/s), is totally independent of the background AGNs has been
challenged by a recent finding that dN/dz for strong MgII absorption
systems toward distant blazars is 2.2±0.80.6 times the value
known for normal optically selected quasars (QSOs). This has led to
the suggestion that a significant fraction of even the absorption
systems with β as high as ∼0.1 may have been ejected by the
relativistic jets in the blazars, which are expected to be pointed
close to our direction. Here, we investigate this scenario using a
large sample of 115 flat-spectrum radio-loud quasars (FSRQs) that also
possess powerful jets, but are only weakly polarized. We show, for the
first time, that dN/dz toward FSRQs is, on the whole, quite similar to
that known for QSOs and that the comparative excess of strong MgII
absorption systems seen toward blazars is mainly confined to
β<0.15. The excess relative to FSRQs probably results from a
likely closer alignment of blazar jets with our direction; hence, any
gas clouds accelerated by them are more likely to be on the line of
sight to the active quasar nucleus.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 66 115 Basic properties of our sample of 115 (nonblazar)
Flat-Spectrum Radio Quasars (FSRQs)
table3.dat 61 75 MgII absorption systems and their rest-frame
equivalent widths, Wr(MgII2796)
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See also:
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
J/A+A/546/A67 : Catalog of strong MgII absorbers (Lawther+, 2012)
J/ApJ/748/131 : MgII absorbers in SDSS-DR7 quasar catalog (Shen+, 2012)
J/ApJ/732/110 : SDSS 2175Å extinction bump candidates (Jiang+, 2011)
J/ApJ/714/1521 : Spectroscopy of galaxies around distant QSOs (Chen+, 2010)
J/ApJ/698/819 : MgII and LRGs cross-correlation analysis (Lundgren+, 2009)
J/ApJ/679/239 : Associated MgII absorbers (Vanden+, 2008)
J/ApJS/171/61 : All-Sky Survey of FSRQs - CRATES (Healey+, 2007)
J/ApJ/660/1093 : Weak MgII absorbers at 0.4<z<2.4 (Narayanan+, 2007)
J/ApJ/639/766 : SDSS-DR3 strong MgII absorbers (Prochter+, 2006)
J/MNRAS/354/L25 : MgII absorbers in SDSS QSOs (Bouche+, 2004)
J/AJ/106/848 : QSO MgII absorption line systems (Drinkwater+, 1993)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Flat spectrum radio quasar (FSRQ) name
18- 25 F8.6 --- zem [0.6/3.8] NED emission redshift
27- 32 F6.3 --- alpha [-0.5/1.3] Radio spectral index α (G1)
34- 38 I5 mJy F4.8 [89/10938] The CRATES (Cat. J/ApJS/171/61)
4.8GHz flux density
40- 44 F5.2 mag mag [16/21] Veron-Cetty & Veron 2010, Cat. VII/258,
magnitude in filter F
46 A1 --- F [OPBVRI] Photometry filter (1)
48- 53 F6.4 --- Dz(w) Redshift path Δz for weak system (2)
55 I1 --- Nw Number of weak systems above 5σ (3)
57- 62 F6.4 --- Dz(s) Redshift path Δz for strong system (4)
64 I1 --- Ns Number of strong systems above 5σ (5)
66 I1 --- Ref Reference code (G2)
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Note (1): Filter as follows:
P = Photographic;
B = Blue;
V = Visible;
R = Red;
I = Infrared;
O = Photographic O/J-plates.
Note (2): Weak = 0.3Angstrom rest-frame equivalent detection threshold
above 5σ significance level.
Note (3): Weak = Rest-frame equivalent width =>0.3Angstroms and <1.0Angstroms.
Note (4): Strong = 1Angstrom rest-frame equivalent detection threshold
above 5σ significance level.
Note (5): Strong = Rest-frame equivalent width ≥1.0Angstroms.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Flat spectrum radio quasars name
18- 23 F6.4 --- zem [0.7/3.8] NED emission redshift
25- 30 F6.4 --- zabs [0.2/2.7] Absorption redshift of MgII system
32- 35 F4.2 0.1nm EW [0.3/5.4] MgII 2796 rest-frame equivalent
width; in Angstrom units
37- 40 F4.2 0.1nm e_EW Error in EW
42- 46 F5.2 --- alpha Radio spectral index α (G1)
48- 53 F6.1 mJy F4.8 [89/4135] The CRATES (Cat. J/ApJS/171/61)
4.8GHz flux density
55- 59 F5.1 --- SNR [9/303]? Signal-to-noise ratio (1)
61 I1 --- Ref Reference code (G2)
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Note (1): Per resolution element around each detected MgII systems, except
for Ellison et al. (2004ApJ...615..118E 2004ApJ...615..118E). Here spectral resolution for
all our spectra is taken to be 45000, which is around the typical
median spectral resolution of our sample in the other data sets.
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Global notes:
Note (G1): Defined by Flux Fν∝να.
Note (G2): References of the radio-selected (or ESO archive for Ref "4")
quasars as follows (see table 1 for further details):
1 = Ellison et al. 2004ApJ...615..118E 2004ApJ...615..118E (ISIS/WHT(4m), EFOSC2/ESO(3.6m) and
FORS1/VLT(UT3));
2 = Bernet et al. 2010ApJ...711..380B 2010ApJ...711..380B (UVES/VLT(U2);
3 = Jorgenson et al. 2006ApJ...646..730J 2006ApJ...646..730J (HIRES/Keck);
4 = Narayanan et al. 2007, Cat. J/ApJ/660/1093 (UVES/VLT(UT2)).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 28-Feb-2014