J/ApJS/208/25 Swift X-ray observations of 1FGL sources (Takeuchi+, 2013)
Multiband diagnostics of unidentified 1FGL sources with Suzaku and Swift X-ray
observations.
Takeuchi Y., Kataoka J., Maeda K., Takahashi Y., Nakamori T., Tahara M.
<Astrophys. J. Suppl. Ser., 208, 25 (2013)>
=2013ApJS..208...25T 2013ApJS..208...25T
ADC_Keywords: X-ray sources ; Gamma rays ; Active gal. nuclei ;
Photometry, UBV ; Photometry, ultraviolet ; Radio sources
Keywords: galaxies: active - gamma rays: general - radiation mechanisms: general
X-rays: general
Abstract:
We have analyzed all the archival X-ray data of 134 unidentified
(unID) gamma-ray sources listed in the first Fermi/LAT (1FGL) catalog
and subsequently followed up by the Swift/XRT. We constructed the
spectral energy distributions (SEDs) from radio to gamma-rays for each
X-ray source detected, and tried to pick up unique objects that
display anomalous spectral signatures. In these analyses, we target
all the 1FGL unID sources, using updated data from the second
Fermi/LAT (2FGL) catalog on the Large Area Telescope (LAT) position
and spectra. We found several potentially interesting objects,
particularly three sources, 1FGL J0022.2-1850, 1FGL J0038.0+1236, and
1FGL J0157.0-5259, which were then more deeply observed with Suzaku as
a part of an AO-7 program in 2012. We successfully detected an X-ray
counterpart for each source whose X-ray spectra were well fitted by a
single power-law function. The positional coincidence with a bright
radio counterpart (currently identified as an active galactic nucleus,
AGN) in the 2FGL error circles suggests these sources are definitely
the X-ray emission from the same AGN, but their SEDs show a wide
variety of behavior. In particular, the SED of 1FGL J0038.0+1236 is
not easily explained by conventional emission models of blazars. The
source 1FGL J0022.2-1850 may be in a transition state between a
low-frequency peaked and a high-frequency peaked BL Lac object, and
1FGL J0157.0-5259 could be a rare kind of extreme blazar.
Description:
Swift is a gamma-ray observatory launched on 2004 November 20. The
primary goal of this mission is to explore and follow-up on gamma-ray
bursts, but high mobility and sensitivity to localized sources,
especially using the X-Ray Telescope (XRT) and UVOT, also make it
viable for follow-up of unID gamma-ray objects discovered by
Fermi/LAT. Here we tried to perform a systematic and uniform analysis
of unID gamma-ray sources in 1FGL (Cat. J/ApJS/188/405) observed thus
far with Swift using archival data. We performed an analysis of UVOT
data only when the X-ray counterpart of the 1FGL source was found in
the Swift/XRT FoV.
To construct SEDs of each 1FGL source, we used not only the Swift/XRT
and Swift/UVOT flux data analyzed in this paper but also gamma-ray
fluxes listed in the 2FGL catalog (Cat. J/ApJS/199/31), and radio
fluxes mostly from the NED database and W3Browse (HEARSAC) based on a
variety of catalogs.
We observed three Fermi/LAT objects that exhibited potentially
interesting or anomalous SEDs (1FGL J0022.2-1850, J0038.0+1236 and
J0157.0-5259) with the Suzaku X-ray astronomy satellite in 2012 May
28-29 and Jun 29. See section 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 69 267 *Swift/XRT results for 112 1FGL objects
table5.dat 192 169 All radio fluxes and Swift/UVOT fluxes plotted
in SEDs (Figure 12)
table6.dat 193 168 Swift/XRT X-Ray fluxes and 2FGL gamma-ray fluxes
plotted in SEDs (Figure 12)
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Note on table4.dat: This table only shows the details of high signal-to-noise
(3σ) sources detected within the Swift/XRT FoV.
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See also:
J/ApJS/207/4 : Unid. γ-ray sources. III. Radio (Massaro+, 2013)
J/ApJS/206/17 : New gamma-ray blazar candidates in the 3PBC (Maselli+, 2013)
J/ApJS/206/13 : Blazars with γ-ray counterparts. II. (Massaro+, 2013)
J/ApJS/206/12 : Blazars with γ-ray counterparts. I. (D'Abrusco+, 2013)
J/A+A/551/A142 : 7 year Swift-XRT point source cat. (1SWXRT) (D'Elia+, 2013)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/MNRAS/426/1750 : INTEGRAL/IBIS AGN catalogue (Malizia+, 2012)
J/A+A/541/A160 : X & gamma-ray obs. of selected blazars (Giommi+, 2012)
J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)
J/MNRAS/403/945 : Swift/XRT obs. of unidentified IBIS sources (Landi+, 2010)
J/ApJ/709/1407 : SED of the Fermi blazars (Li+, 2010)
J/ApJ/706/L7 : The Fermi LAT sky as seen by INTEGRAL/IBIS (Ubertini+, 2009)
J/ApJ/681/113 : Swift BAT survey of AGNs (Tueller+, 2008)
J/ApJ/678/102 : BAT X-ray survey. I. (Ajello+, 2008)
J/A+A/458/245 : Obs. of 2 Unid. Gamma-ray Sources (La Palombara+, 2006)
J/A+A/436/799 : X- & gamma-ray fluxes of γ-ray-loud blazars (Fan+, 2005)
J/A+A/379/755 : Radio data of X- and gamma-ray loud blazars (Venturi+, 2001)
http://heasarc.nasa.gov/W3Browse/all/radio.html : W3Browse HEARSAC master
radio catalog
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- Fig Figure number in Figure 11 (G1)
5- 8 A4 --- --- [1FGL]
10- 21 A12 --- 1FGL 1FGL source name (JHHMM.m+DDMM)
23 I1 --- XRT [1/7] XRT source number within Name
25- 32 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
34- 41 F8.4 deg DEdeg Declination in decimal degrees (J2000)
43- 46 F4.2 arcsec r90 [3.5/8.3] Radius of 90% confidence error circles
48- 55 E8.3 ct/ks CRate [0.1/81.6] Count rate in 0.3-10keV band
57- 64 E8.2 ct/ks e_CRate [0.4/21] Uncertainty in CRate
66- 69 F4.1 --- S/N [3/47.1] Signal-to-Noise ratio
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- Fig Figure number in Figure 11 (G1)
5- 16 A12 --- 1FGL 1FGL source name (JHHMM.m+DDMM)
17 A1 --- --- [_ ]
18- 37 A20 --- Name Name complement as in figure 12
39 A1 --- l_F350 Limit flag on F350
40- 45 F6.3 mJy F350 [0.3/20]? Radio 350MHz flux density
47- 51 F5.3 mJy e_F350 [0.001/0.1]? Uncertainty in F350
53 A1 --- l_F843 Limit flag on F843
54- 59 F6.1 mJy F843 [5/2820]? Radio 843MHz flux density
61- 63 F3.1 mJy e_F843 [1/4]? Uncertainty in F843
65 A1 --- l_F1.4 Limit flag on F1.4
66- 73 F8.3 mJy F1.4 [0.02/952]? Radio 1.4GHz flux density
75- 79 F5.2 mJy e_F1.4 [0.01/11]? Uncertainty in F1.4
81- 84 F4.1 mJy F4.85 [78]? Radio 4.85GHz flux density
86- 88 F3.1 mJy e_F4.85 [4/8]? Uncertainty in F4.85
90 A1 --- l_Vflx Limit flag on Vflx
91- 96 F6.3 fW/m2 Vflx [0.28/84]? Swift/UVOT V band flux
98-102 F5.3 fW/m2 e_Vflx [0.06/2]? Uncertainty in Vflx
104 A1 --- l_Bflx Limit flag on Bflx
105-110 F6.3 fW/m2 Bflx [0.25/57.9]? Swift/UVOT B band flux
112-116 F5.3 fW/m2 e_Bflx [0.04/1.1]? Uncertainty in Bflx
118 A1 --- l_Uflx Limit flag on Uflx
119-126 F8.4 fW/m2 Uflx [0.02/193]? Swift/UVOT U band flux
128-132 F5.3 fW/m2 e_Uflx [0.01/4]? Uncertainty in Uflx
134 A1 --- l_W1flx Limit flag on W1flx
135-143 F9.4 fW/m2 W1flx [0.09/2615]? Swift/UVOT W1 band
(lambda0=2600Å) flux
145-152 F8.3 fW/m2 e_W1flx [0.01/2550]? Uncertainty in W1flx
154 A1 --- l_M2flx Limit flag on M2flx
155-163 F9.4 fW/m2 M2flx [0.046/4886]? Swift/UVOT M2 band
(lambda0=2246Å) flux
165-173 F9.4 fW/m2 e_M2flx [0.006/4874]? Uncertainty in M2flx
175 A1 --- l_W2flx Limit flag on W2flx
176-184 F9.5 fW/m2 W2flx [0.03/108]? Swift/UVOT W2 band
(lambda0=1928Å) flux
186-192 F7.5 fW/m2 e_W2flx [0.01/2]? Uncertainty in W2flx
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I03 --- Fig Figure number in Figure 11 (G1)
5- 16 A12 --- 1FGL 1FGL source name
17 A1 --- --- [_ ]
18- 37 A20 --- Name Name complement as in Figure 12
39- 46 F8.3 10-17W/m2 F0.3-0.6k [0.7/1151]? Swift/XRT 0.32-0.64keV flux
48- 54 F7.3 10-17W/m2 e_F0.3-0.6k [0.2/386]? Uncertainty in F0.3-0.6k
56- 62 F7.3 10-17W/m2 F0.6-1k [0.7/872]? Swift/XRT 0.64-1.28keV flux
64- 70 F7.3 10-17W/m2 e_F0.6-1k [0.6/157]? Uncertainty in F0.6-1k
72- 77 F6.2 10-17W/m2 F1-2k [1.1/737]? Swift/XRT 1.28-2.56keV flux
79- 84 F6.2 10-17W/m2 e_F1-2k [0.7/117]? Uncertainty in F1-2k
86- 92 F7.3 10-17W/m2 F2-5k [0.6/825]? Swift/XRT 2.56-5.12keV flux
94-100 F7.3 10-17W/m2 e_F2-5k [1.3/201]? Uncertainty in F2-5k
102-108 F7.2 10-17W/m2 F5-10k [9.5/1510]? Swift/XRT 5.12-10.24keV flux
110-115 F6.2 10-17W/m2 e_F5-10k [9.1/134]? Uncertainty in F5-10k
117 A1 --- l_UL0.5-8k Upper limit on UL0.5-8k
118-124 F7.2 10-17W/m2 UL0.5-8k [4.8/480]? Upper limit on Swift/XRT
0.5-8keV flux
126 A1 --- l_F0.1-0.3G Upper limit on F0.1-0.3G
127-134 F8.4 fW/m2 F0.1-0.3G [0.8/13] 2FGL catalog 100-300 MeV flux
136-139 F4.2 fW/m2 e_F0.1-0.3G [0.6/2]? Uncertainty in F0.1-0.3G
141 A1 --- l_F0.3-1G Upper limit on F0.3-1G
142-147 F6.3 fW/m2 F0.3-1G [0.7/16] 2FGL catalog 0.3-1GeV flux
149-152 F4.2 fW/m2 e_F0.3-1G [0.3/1]? Uncertainty in F0.3-1G
154 A1 --- l_F1-3G Upper limit on F1-3G
155-160 F6.3 fW/m2 F1-3G [0.7/15.2] 2FGL catalog 1-3GeV flux
162-166 F5.3 fW/m2 e_F1-3G [0.2/1]? Uncertainty in F1-3G
168 A1 --- l_F3-10G Upper limit on F3-10G
169-174 F6.3 fW/m2 F3-10G [0.5/8.8] 2FGL catalog 3-10GeV flux
176-180 F5.3 fW/m2 e_F3-10G [0.3/1.1]? Uncertainty in F3-10G
182 A1 --- l_F10-100G Upper limit on F10-100G
183-188 F6.3 fW/m2 F10-100G [0.6/5.2] 2FGL catalog 10-100GeV flux
190-193 F4.2 fW/m2 e_F10-100G [0.6/1.3]? Uncertainty in F10-100G
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Global note:
Note (G1): Column added by CDS: the 134 numbers corresponding to 1FGL names
given in Figure 11.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 31-Oct-2013