J/ApJ/590/109 Gamma-ray blazar in northern sky (Sowards-Emmerd+, 2003)
The gamma-ray blazar content of the northern sky.
Sowards-Emmerd D., Romani R.W., Michelson P.F.
<Astrophys. J., 590, 109-122 (2003)>
=2003ApJ...590..109S 2003ApJ...590..109S
ADC_Keywords: Surveys ; BL Lac objects ; Radio sources ; Gamma rays
Keywords: BL Lacertae objects: general - galaxies: active -
gamma rays: observations - surveys
Abstract:
Using survey data, we have re-evaluated the correlation of
flat-spectrum radio sources with EGRET sources in the northern sky.
An analysis incorporating the radio and X-ray properties and the
gamma-ray source localization is used to gauge the reliability of
associations and to search for counterparts of previously unidentified
EGRET sources. Above |b|=10°, where the classification is
complete, we find that 70% of the northern EGRET sources have
counterparts similar to the bright EGRET blazars. For several of these
we identify known blazar counterparts more likely than the earlier
proposed 3EG association; for ∼20 we have new identifications.
Spectroscopic confirmation of these candidates is in progress, and we
have found flat-spectrum radio quasars and BL Lacertae counterparts
with redshifts as high as 4. We also find strong evidence for a set of
28 objects with no plausible counterpart like the known EGRET blazars.
These thus represent either a new extragalactic population or a
population of Galactic objects with a large scale height. The survey
has been extended into the plane, where we find several new blazar
candidates; the bulk of the sources are, however, Galactic. Looking
ahead to the GLAST era, we predict that several of the present 3EG
sources are composite and that higher resolution data will break these
into multiple blazar identifications.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 158 Northern 3EG Objects
notes.dat 80 143 Individual notes on 3EG Objects
table2.dat 64 45 New 3EG Counterpart Candidates with
Spectroscopic Identification
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See also:
J/ApJS/123/79 : Third EGRET catalog (3EG) (Hartman+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- 3EG The 3rd EGRET Catalog blazar source name
11 A1 --- f_3EG [:] J1824+3440 modified into J1824+3441
12- 39 A28 --- Names Object identifications
41 A1 --- u_Names [ibl] Flag on Names (1)
43- 47 I5 mJy S8.4GHz ? The 8.4GHz flux density
49- 53 F5.2 --- SpIndex ? Spectral index (2)
55- 59 F5.2 --- FoM ? Figure of Merit (G1)
61- 64 F4.2 --- z ? Redshift
66- 67 A2 --- Note Association and/or redshift note (3)
69 A1 --- MBlaz [±] Blazar probability from Mattox et al.
(2001, Cat. J/ApJS/135/155) (4)
71 A1 --- EBlaz [Aa] Blazar confidence from 3EG (5)
73- 75 A3 --- Class Classification (G2)
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Note (1): Note on Names as follows:
l = a lower confidence association;
b = a high confidence association;
i = previously claimed AGN association not supported by the analysis.
Note (2): Where Sν ∝ ν{-SpIndex}.
Note (3): Note as follows:
* = new spectral identification
dg = redshift from NED, 10th QSO Catalog, etc.
Note (4): Mattox et al. (2001, Cat. J/ApJS/135/155) blazar flag:
+ = High probability;
- = Plausible.
Note (5): 3rd EGRET Catalog (J/ApJS/123/79) blazar flag:
A = High confidence;
a = lower confidence.
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [3EG]
5- 14 A10 --- 3EG 3EG source designation
16- 90 A75 --- Note Text of the note
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Object identification (JHHMM+DDMM)
12- 15 F4.2 --- FoM Figure of Merit (G1)
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 28 F6.3 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 41 F5.2 arcsec DEs Declination (J2000)
43- 47 F5.2 mag R2mag ?=- USNO B1.0 R2 magnitude
49- 53 F5.2 mag B2mag ?=- USNO B1.0 B2 magnitude
55- 59 F5.3 --- z ? Redshift
60 A1 --- u_z Uncertainty flag on z
61 A1 --- n_z [*] indicates new redshifts
(other archival ones)
63- 64 A2 --- Class Classification (G2)
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Globla notes:
Note (G1): We combine the fractional excesses for each of the counterpart
candidate's properties with the estimate of the positional probability
to compute a total "figure of merit" (FoM) for the source as a
radio/X-ray counterpart:
FoM = n(8.4GHz) x n(RA) x n(X-ray) x L(RA,DE).
Note that this product of excess source fraction and positional
uncertainty is not a normalized probability of source identification.
It is, however, an unbiased ranking of the counterpart likelihood that
can be compared across the entire (high-latitude) 3EG population. To
avoid confusion, we multiply by 100 in the quoted FoM values.
Note (G2): Classification is defined as follows:
f = FSRQ
b = BL Lac
R = narrow-line radio galaxy
G = Likely galactic
N = Non-blazar
p = Pulsar candidate/plerion
P = confirmed pulsar
S = Solar flare
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 19-Sep-2005