J/ApJ/767/14 MASIV survey III. Optical identifications (Pursimo+, 2013)
The Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey.
III. Optical identifications and new redshifts.
Pursimo T., Ojha R., Jauncey D.L., Rickett B.J., Dutka M.S., Koay J.Y.,
Lovell J.E.J., Bignall H.E., Kedziora-Chudczer L., Macquart J.-P.
<Astrophys. J., 767, 14 (2013)>
=2013ApJ...767...14P 2013ApJ...767...14P
ADC_Keywords: Active gal. nuclei ; Radio sources ; Redshifts ; Photometry, RI
Keywords: BL Lacertae objects: general; galaxies: distances and redshifts;
galaxies: ISM; intergalactic medium; quasars: general
Abstract:
Intraday variability (IDV) of the radio emission from active galactic
nuclei is now known to be predominantly due to interstellar
scintillation (ISS). The MASIV (The Micro-Arcsecond
Scintillation-Induced Variability) survey of 443 flat spectrum sources
revealed that the IDV is related to the radio flux density and
redshift. A study of the physical properties of these sources has been
severely handicapped by the absence of reliable redshift measurements
for many of these objects. This paper presents 79 new redshifts and a
critical evaluation of 233 redshifts obtained from the literature. We
classify spectroscopic identifications based on emission line
properties, finding that 78% of the sources have broad emission lines
and are mainly FSRQs. About 16% are weak lined objects, chiefly BL
Lacs, and the remaining 6% are narrow line objects. The gross
properties (redshift, spectroscopic class) of the MASIV sample are
similar to those of other blazar surveys. However, the extreme
compactness implied by ISS favors FSRQs and BL Lacs in the MASIV
sample as these are the most compact object classes. We confirm that
the level of IDV depends on the 5GHz flux density for all optical
spectral types. We find that BL Lac objects tend to be more variable
than broad line quasars. The level of ISS decreases substantially
above a redshift of about two. The decrease is found to be generally
consistent with ISS expected for beamed emission from a jet that is
limited to a fixed maximum brightness temperature in the source rest
frame.
Description:
The new redshifts reported in this paper were obtained using the 2.56m
Nordic Optical Telescope (NOT) which is located at Roque de los
Muchachos, La Palma, Canary Islands, Spain and the 5 m Hale Telescope
at Mount Palomar, California, USA. Most of the NOT data were obtained
during two observing runs (2005 July 3-7 and 2006 July 22-28)
supplemented by a few additional nights between 2004 January and 2007
July. The Mount Palomar data were obtained during an observing run
from 2007 August 9 to 10.
For optical identification we used the CDS client database to access
three large area surveys, the Sloan Digital Sky Survey (SDSS), the
Guide Star Catalog 2.3 (GSC) and the USNO-B1 Catalog. See section 3.2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 133 347 MASIV data
refs.dat 114 145 References
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See also:
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
VIII/72 : CLASS survey of radio sources (Myers+, 2003)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
III/175 : Optical spectroscopy of radio sources (Stickel+, 1989-94)
J/ApJ/756/29 : Scintillation of AGNs observed with the VLA (Koay+, 2012)
J/AJ/142/108 : Radio variability of compact flat-spectrum AGNs (Koay+, 2011)
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/ApJ/689/108 : MASIV survey. II. First four epochs (Lovell+, 2008)
J/ApJS/175/97 : CGRaBS: γ-ray blazar candidates survey (Healey+, 2008)
J/A+A/463/97 : Optical observations of GPS radio sources (Labiano+, 2007)
J/ApJS/171/61 : All-Sky Survey of Flat-Spectrum Radio Sources (Healey+, 2007)
J/ApJS/165/439 : Interstellar scintillation at 2 and 8GHz (Rickett+, 2006)
J/ApJ/626/95 : Gamma-ray blazar candidates (Sowards-Emmerd+, 2005)
J/ApJ/609/564 : Blazar counterparts for 3EG sources (Sowards-Emmerd+, 2004)
J/MNRAS/351/83 : Blazars equivalent widths and radio luminosity (Landt+, 2004)
J/MNRAS/348/937 : The CLASS blazar survey. III. (Caccianiga+, 2004)
J/MNRAS/323/757 : Deep X-Ray Radio Blazar Survey (DXRBS). II. (Landt+, 2001)
J/ApJS/126/133 : The FIRST bright quasar survey. II. (White+, 2000)
J/A+A/342/378 : 6 and 20cm flux densities of radio galaxies (Gurvits+ 1999)
J/AJ/115/1253 : Deep X-Ray Radio Blazar Survey (DXRBS). I. (Perlman+ 1998)
J/ApJS/117/319 : Northern RASS X-ray sources catalog (Appenzeller+ 1998)
J/ApJS/98/477 : Optical spectral atlas of Seyfert nuclei (Ho+ 1995)
J/A+AS/103/349 : Optical identification of S4 sources (Stickel+ 1994)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- MASIV Source name (JHHMM+DDMM)
12- 13 I2 h RAh Hour of Right Ascension (J2000)
15- 16 I2 min RAm Minute of Right Ascension (J2000)
18- 24 F7.4 s RAs Second of Right Ascension (J2000)
26 A1 --- DE- [+] Sign of Declination (J2000)
27- 28 I2 deg DEd Degree of Declination (J2000)
30- 31 I2 arcmin DEm Arcminute of Declination (J2000)
33- 38 F6.3 arcsec DEs Arcsecond of Declination (J2000)
40- 44 F5.2 Jy S5 [0.06/18.1] MASIV first epoch 5GHz flux density
46 I1 --- Nep [0/4] Number of epochs of variability based on
visual classification from L08 (1)
47 A1 --- n_MASIV [C] C = secondary calibrators
49- 57 E9.3 --- D2 [0/0.3] Structure function D(2days) from L08 (1)
59- 62 F4.2 mag E(B-V) [0/1] Galactic extinction
64- 68 F5.2 mag Rmag [0/23.1] Galactic extinction corrected R band
magnitude
70- 72 A3 --- r_Rmag Reference for Rmag (see refs.dat file)
74- 81 F8.6 --- z [0/4.1] Redshift
84- 85 A2 --- EmLT Emission line type (T0, T1 or T2) (2)
88- 98 A11 --- Class Spectroscopic identification (3)
100-109 A10 --- Ref Reference(s) for z and Class (see refs.dat file)
111-133 A23 --- Comm Additional comments
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Note (1): L08 = Lovell et al. 2008, J/ApJ/689/108 (Paper II).
Note (2): On the basis of the optical spectrum the sources have been divided
into three main groups (see sections 4.1 and 4.3 for further explanations):
T0 = objects with weak emission lines (mainly BL Lacs),
T1 = objects with strong and broad emission lines (mainly FSRQ) and
T2 = objects with strong and narrow emission lines (mainly Seyfert 2's).
Note (3): Spectroscopic identifications are:
bll = BL Lac (bll? are BL Lac candidates)
peg = passive elliptical galaxies
fsrq = Flat spectrum radio quasar
sy = Seyfert galaxy (types 1 and 2)
nl = narrow lines (nlqso, NLSy1, nlrg=narrow-line radio galaxy)
galaxy = Galaxy
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Ref Reference code
5- 23 A19 --- BibCode Bibcode
25- 90 A66 --- Aut Author's name(s)
92-114 A23 --- Comm comment
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History:
From electronic version of the journal
References:
Lovell et al. Paper I. 2003AJ....126.1699L 2003AJ....126.1699L
Lovell et al. Paper II. 2008ApJ...689..108L 2008ApJ...689..108L Cat. J/ApJ/689/108
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Nov-2014