J/ApJ/615/897 Chandra X-Ray sources in the γ Cyg Field (Becker+, 2004)
A multiwavelength search for a counterpart of the brightest unidentified
gamma-ray source 3EG J2020+4017 (2CG 078+2).
Becker W., Weisskopf M.C., Arzoumanian Z., Lorimer D., Camilo F.,
Elsner R.F., Kanbach G., Reimer O., Swartz D.A., Tennant A.F., O'Dell S.L.
<Astrophys. J., 615, 897-907 (2004)>
=2004ApJ...615..897B 2004ApJ...615..897B
ADC_Keywords: X-ray sources ; Gamma rays ; Radio sources ; Infrared sources
Keywords: ISM: individual (G78.2+2.1) - X-rays: individual (RX J2020.2+4026)
Abstract:
In search of the counterpart to the brightest unidentified gamma-ray
source, 3EG J2020+4017 (2CG 078+2), we report on new X-ray and radio
observations of the γ Cygni field with the Chandra X-Ray
Observatory and with the Green Bank Telescope (GBT). We also report on
reanalysis of archival ROSAT data.
Description:
Our 30ks Chandra observation (observation ID 3856) was taken on 2003
January 26 using three Advanced CCD Imaging Spectrometer (ACIS) CCDs
(S2, S3, and S4) in the faint, timed-exposure mode with a frame time
of 3.141 s.
A deep search for radio pulsations from 2CG 078+2 was carried out
using the Green Bank Telescope (GBT) on 2003 December 27.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 68 38 Chandra X-Ray sources in the γ Cygni field
table2.dat 70 34 Candidate counterparts to the X-ray sources in
the γ Cygni field
--------------------------------------------------------------------------------
See also:
J/ApJS/123/79 : Third EGRET catalog (3EG) (Hartman+, 1999)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
IX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
IX/30 : Second ROSAT PSPC Catalog (ROSAT, 2000)
IX/32 : ROSAT Bright Survey (Fischer+, 1998-2000)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [BWA2004] Name
7- 15 F9.5 deg RAdeg Right Ascension (J2000)
18- 26 F9.6 deg DEdeg Declination (J2000)
29- 33 F5.2 arcsec r1 Extraction radius
36- 38 I3 ct N Approximate vignetting-corrected number of
source counts
41- 44 F4.1 --- S/N Detection signal-to-noise ratio
47- 50 F4.2 arcsec r2 X-ray position uncertainty (1σ radius)
(1)
53- 56 F4.2 arcsec Sep1 ? Radial separation between X-ray position and
USNO position of counterpart
59- 62 F4.2 arcsec Sep2 ? Radial separation between X-ray position and
2MASS position of counterpart
65- 67 F3.1 arcsec Sep3 ? Radial separation between X-ray position and
ROSAT position of counterpart
68 A1 --- f_Sep3 Flag on Sep3 (2)
--------------------------------------------------------------------------------
Note (1): The positional uncertainty is given by
r=1.51"(σ2/N+σ02)1/2,
where σ is the size of the circular Gaussian that approximately
matches the point-spread function (PSF) at the source location, N is
the vignetting-corrected number of source counts, and σ0
represents the systematic error.
Note (2): The flag on Sep3 is defined as follows:
a = 1RXH J2020.2+4026; the positional uncertainty is 6"
b = 1RXH J202040.9+402704; the positional uncertainty is larger than the
separation (2"-3")
c = 1RXH J202057.8+402829; the positional uncertainty is 1"
d = 1RXH J202111.4+402807; the positional uncertainty is 2"
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [BWA2004] Name
7- 16 F10.6 deg RAdeg ? USNO Right Ascension (J2000)
19- 27 F9.6 deg DEdeg ? USNO Declination (J2000)
30- 34 F5.3 ct N(USNO) ? Average number of accidental coincidences
expected in the region searched (1)
37- 46 F10.6 deg RA2deg ? 2MASS Right Ascension (J2000)
49- 57 F9.6 deg DE2deg ? 2MASS Declination (J2000)
60- 64 F5.3 ct N(2MASS) ? Average number of accidental coincidences
expected in the region searched (1)
67- 70 F4.2 arcsec delta ? Angular separation between the USNO and
2MASS candidate counterpart
--------------------------------------------------------------------------------
Note (1): The probability of getting one or more matches by chance is given
by the Poisson probability 1-exp(-Nr99), which for small values
is approximately Nr99.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Marianne Brouty [CDS] 26-May-2005