J/AJ/153/113 The CGPS 1420 MHz catalog of compact sources (Taylor+, 2017)
A 1420 MHz catalog of compact sources in the northern Galactic plane.
Taylor A.R., Leahy D.A., Tian W.W., Sunstrum C., Kothes R., Landecker T.L.,
Ransom R.R., Higgs L.A.
<Astron. J., 153, 113-113 (2017)>
=2017AJ....153..113T 2017AJ....153..113T (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio continuum ; Radio sources
Keywords: catalogs - radio continuum: general - surveys
Abstract:
We present a catalog of compact sources of radio emission at 1420MHz
in the northern Galactic plane from the Canadian Galactic Plane
Survey. The catalog contains 72758 compact sources with an angular
size less than 3' within the Galactic longitude range
52°<l<192° down to a 5σ detection level of ∼1.2mJy.
Linear polarization properties are included for 12368 sources with
signals greater than 4σQU in the Canadian Galactic Plane
Survey (CGPS) Stokes Q and U images at the position of the total
intensity peak. We compare CGPS flux densities with cataloged flux
densities in the Northern VLA Sky Survey catalog for 10897 isolated
unresolved sources with CGPS flux density greater than 4mJy to search
for sources that show variable flux density on timescales of several
years. We identify 146 candidate variables that exhibit high
fractional variations between the two surveys. In addition, we
identify 13 candidate transient sources that have CGPS flux density
above 10mJy but are not detected in the Northern VLA Sky Survey.
Description:
The Canadian Galactic Plane Survey (CGPS) mapped the principal
constituents of the interstellar medium (ISM) with high angular
resolution, inspired by the view that understanding the ISM requires
knowledge of all its constituents. The Synthesis Telescope at the
Dominion Radio Astrophysical Observatory (the DRAO ST) provided
arcminute-resolution images of the radio continuum and atomic-hydrogen
line emission. The CGPS is presented in Taylor et al. 2003 (Cat.
VI/128), where details are also given of companion surveys that imaged
the molecular and dust constituents of the ISM.
The CGPS DRAO radio continuum observations provide images of Stokes I,
Q, and U in four 7.5MHz sub-bands spanning 35MHz, centered on 1420MHz.
The observations were carried out in three phases beginning in 1995
Apr and ending in 2009 Feb.
The CGPS DRAO image products are 5.12°*5.12° images mosaicked
from overlapping Synthesis Telescope fields. The images are available
through the Canadian Astronomy Data Centre
(www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/cgps). The complete survey is
comprised of 85 such mosaics. We constructed the radio source catalog
from these images using an automated source finding algorithm,
FINDSRC, developed as part of the DRAO export software package (Higgs
et al. 1997ASPC..125...58H 1997ASPC..125...58H).
We present the Canadian Galactic Plane Survey (CGPS) 1420MHz compact
source catalog covering 1464 square degrees and spanning a range of
140° of Galactic longitude between 52°<l<192°.
Our survey is comparable in resolution and sensitivity to the NRAO VLA
Sky Survey (NVSS; Condon et al. 1998, Cat. VIII/65); the flux density
scale and source positions of the CGPS at 1420MHz were tied to the
NVSS. From the 72758 sources in the CGPS catalog we identified 52876
that have counterparts in the NVSS within 60'' of the CGPS position.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 127 72787 Canadian Galactic Plane Survey (CGPS) 1420MHz
source catalog
table3.dat 53 146 *Variable sources detected in Canadian Galactic
Plane Survey (CGPS) and NRAO VLA Sky
Survey (NVSS)
table4.dat 53 13 *Strong Canadian Galactic Plane Survey (CGPS)
sources not detected in the NRAO VLA Sky
Survey (NVSS)
--------------------------------------------------------------------------------
Note on table3.dat: Candidate variables that exhibit high fractional variations
between the Canadian Galactic Plane Survey (CGPS; see Taylor et al. 2003,
Cat. VI/128) and the NRAO VLA Sky Survey (NVSS; Condon et al. 1998,
Cat. VIII/65).
Note on table4.dat: Candidate transient sources that have Canadian Galactic
Plane Survey (CGPS; see Taylor et al. 2003, Cat. VI/128) flux density
above 10mJy but are not detected in the NRAO VLA Sky Survey (NVSS; Condon et
al. 1998, Cat. VIII/65).
--------------------------------------------------------------------------------
See also:
VI/128 : Log of CGPS exposures (Taylor+, 2003-)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/ApJ/702/1230 : Rotation measure image of the sky (Taylor+, 2009)
J/ApJS/145/213 : Rotation measures of compact sources in CGPS (Brown+, 2003)
www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/cgps : Canadian Galactic Plane Survey
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [CGPS]
6- 19 A14 --- CGPS Canadian Galactic Plane Survey (CGPS)
identifier (JHHMMSS+DDMMSS)
21- 29 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
31- 35 F5.2 deg e_RAdeg The 1σ uncertainty in RAdeg
37- 44 F8.5 deg DEdeg Declination in decimal degrees (J2000)
46- 49 F4.1 deg e_DEdeg The 1σ uncertainty in DEdeg
51- 56 F6.1 mJy SI [1/9516.5] Integrated Stokes I flux density
(SI)
58- 64 F7.2 mJy e_SI [0.2/2613.2] The 1σ uncertainty in SI
66- 71 F6.1 mJy/beam SP [1/6228.7] Peak Stokes I intensity (SP)
73- 79 F7.2 mJy/beam e_SP [0.2/2613.2] The 1σ uncertainty in SP
81- 85 F5.2 mJy sigma [0/48.3]?=0 Average rms (σQU) (1)
87- 91 F5.1 mJy/beam P [0/295.9] Bias corrected polarized
intensity (2)
93- 97 F5.2 mJy/beam e_P [0.11/19]?=0 The 1σ uncertainty in P
99-101 I3 deg PA1 [-90/89] Polarization position angle
103-107 F5.1 arcsec MajAxis [0.4/179.9]?=0 Deconvolved major axis
(σmaj) (3)
109-112 F4.1 arcsec e_MajAxis [0.1/36.6]?=0 The 1σ uncertainty in
MajAxis
114-118 F5.1 arcsec MinAxis [0.3/151.2]?=0 Deconvolved minor axis
(σmin) (3)
120-123 F4.1 arcsec e_MinAxis [0.1/29.2]?=0 The 1σ uncertainty in
MinAxis
125-127 I3 deg PA2 [1/180]?=0 Deconvolved major axis position
angle with respect to North (J2000)
--------------------------------------------------------------------------------
Note (1): Around the position of the source in the Q and U images.
Note (2): In the case of detected polarized emission.
Note (3):
Of the Stokes I emission. The deconvolved source dimensions are listed
as zero if the source is classed as unresolved. The beam dimensions at the
location of the source can be calculated using Equation (1):
bmajor*bminor=49''cosecδ*49'',
where bmajor and bminor are respectively in the decl. and R.A.
directions.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [CGPS]
6- 19 A14 --- CGPS Canadian Galactic Plane Survey (CGPS)
identifier (JHHMMSS+DDMMSS)
21- 25 F5.1 mJy SCGPS [4.3/736.6] CGPS integrated Stokes I flux
density (SCGPS)
27- 30 F4.1 mJy e_SCGPS [0.3/21.5] Uncertainty in SCGPS
32- 36 F5.1 mJy SNVSS [2.2/495] NRAO VLA Sky Survey (NVSS)
integrated Stokes I flux density (SNVSS)
38- 41 F4.1 mJy e_SNVSS [0.4/14.9] Uncertainty in SNVSS
43- 47 F5.2 --- F [-0.8/1.4] Change in flux density between
CGPS & NVSS (1)
49- 53 F5.2 --- V [-5.6/10.5] Variability index (2)
--------------------------------------------------------------------------------
Note (1):
As a fraction of the mean flux density measured between the two surveys,
F=2[(SCGPS-SNVSS)/(SCGPS+SNVSS)].
A change in flux density by a factor of 2 results in F=±0.67.
Note (2):
We identify as variables sources those for which:
V=(F-FMED)/e_F>4,
where FMED is the median value of F for population.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [CGPS]
6- 19 A14 --- CGPS Canadian Galactic Plane Survey (CGPS)
identifier (JHHMMSS+DDMMSS)
21- 24 F4.1 mJy SCGPS [10/24.8] CGPS integrated Stokes I intensity
(SCGPS)
26- 28 F3.1 mJy e_SCGPS [0.4/1.5] Uncertainty in SCGPS
30- 53 A24 --- Com Comment
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 10-Jul-2017