J/ApJ/848/103 ∼1.5yr Swift observations of Mrk 421 (Kapanadze+, 2017)
Mrk 421 after the giant X-ray outburst in 2013.
Kapanadze B., Dorner D., Romano P., Vercellone S., Kapanadze S.,
Tabagari L.
<Astrophys. J., 848, 103-103 (2017)>
=2017ApJ...848..103K 2017ApJ...848..103K (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects; X-ray sources ; Ultraviolet
Keywords: BL Lacertae objects: Mrk 421
Abstract:
We present the results of the Swift observations of the nearby BL Lac
object Mrk421 during 2013 November-2015 June. The source exhibited a
strong long-term variability in the 0.3-10keV band, with a
maximum-to-minimum flux ratio of 13, and underwent X-ray flares by a
factor of 1.8-5.2 on timescales of a few weeks or shorter. The source
showed 48 instances of intraday flux variability in this period, which
sometimes was observed within the 1 ks observational run. It was
characterized by fractional amplitudes of 1.5(0.3)%-38.6(0.4)% and
flux doubling/halving times of 2.6-20.1hr. The X-ray flux showed a
lack of correlation with the TeV flux on some occasions (strong TeV
flares were not accompanied by comparable X-ray activity and vice
versa), indicating that the high-energy emission in Mrk421 was
generated from an emission region more complex than a single zone. The
best fits of the 0.3-10keV spectra were mainly obtained using the
log-parabola model, showing a strong spectral variability that
generally followed a "harder-when-brighter" trend. The position of the
synchrotron spectral energy distribution peak showed an extreme range
from a few eV to ∼10keV that happens rarely in blazars.
Description:
In this paper, we present the results related to the X-ray timing and
spectral behavior of the nearby high-frequency-peaked object (HBL)
source Mrk 421 (z=0.031) during 2013November-2015 June, after its
giant X-ray outburst in 2013 April (e.g. Papre I: Kapanadze+ 2016,
J/ApJ/831/102).
We concentrate on the 0.3-10keV band observations performed with the
X-ray Telescope (XRT) on board Swift.
Along with these data, we have analyzed observations performed with
the Ultraviolet/Optical Telescope (UVOT) and the Burst Alert Telescope
(BAT) on board Swift. We also constructed light curves using the
publicly available TeV (FACT), high-energy (HE, E>1MeV; Large Area
Telescope (LAT) on board Fermi), optical (R and V bands of
Johnson-Cousins system; different Earth-based telescopes), and radio
(the Owens Valley Radio Observatory (OVRO) 40m telescope)
observations.
Objects:
-------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------
11 04 27.31 +38 12 31.8 Mrk 421 = 2MAXI J1104+382
-------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 144 161 The summary of the XRT and UVOT observations in
2013 November - 2015 June
table3.dat 204 67 Summary of the intraday 0.3-10keV variabilities
in 2013 November - 2015 June
table4.dat 131 540 The results of the XRT spectral analysis with
the logparabolic model
table7.dat 109 28 The results of the XRT spectral analysis with
a simple PL model
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See also:
IX/43 : 1SXPS Swift X-ray telescope point source catalogue (Evans+ 2014)
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
J/ApJS/232/7 : 8yr R-band photopolarimetric data of Mrk 421 (Fraija+, 2017)
J/ApJ/831/102 : Swift and NuSTAR obs. of the BL Lac Mrk 421 (Kapanadze+, 2016)
J/A+A/593/A91 : Mrk 421 multi-wavelength variability, 2007-2009 (Ahnen+, 2016)
J/ApJS/222/6 : 4.5yr obs. of Mrk421 with ARGO-YBJ + Fermi (Bartoli+, 2016)
J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
J/A+A/578/A22 : Mrk421 in March 2010 (Aleksic+, 2015)
J/A+A/576/A126 : The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)
J/MNRAS/439/690 : Optical/γ-ray variability in blazars (Hovatta+, 2014)
J/MNRAS/438/3058 : 15GHz variability of γ-ray blazars (Richards+, 2014)
J/A+A/563/A57 : Long-term variability of AGN at hard X-rays (Soldi+, 2014)
J/ApJS/209/14 : The Swift/BAT hard X-ray transient monitor (Krimm+, 2013)
J/A+A/559/A75 : 43GHz observation of the blazar Mrk 421 (Blasi+, 2013)
J/A+A/548/A79 : INTEGRAL-OMC opt. variable sources (Alfonso-Garzon+, 2012)
J/A+A/545/A117 : Monitoring of Mrk 421 at 15 and 24 GHz (Lico+, 2012)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
J/AJ/137/5022 : Variability of radio-bright BL Lac objects (Nieppola+, 2009)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 I11 --- obsID [31202141/92204008] Observation identifier
13- 22 A10 "Y/M/D" st.date UTC date of observation start
24- 31 A8 "h:m:s" st.time UTC time of observation start
33- 42 A10 "Y/M/D" end.date UTC date of observation end
44- 51 A8 "h:m:s" end.time UTC time of observation end
53- 57 I5 s Exp [22/10000] Exposure time
59- 67 F9.3 d MJD Modified Julian date of the observation start
69- 73 F5.2 ct/s XRT [7/100] Observation-binned 0.3-10keV
count rate
75- 78 F4.2 ct/s e_XRT [0.08/1.2] Uncertainty in XRT
80- 84 F5.2 mag uvw1mag [11/12.1]? De-reddened Swift/UVOT uvw1 band
magnitude
86- 89 F4.2 mag e_uvw1mag [0.03/0.2]? Uncertainty in uvw1mag
91- 95 F5.2 mJy Fuvw1 [13.2/33.4]? De-reddened Swift/UVOT uvw1 band
flux density
97-100 F4.2 mJy e_Fuvw1 [0.05/1.3]? Uncertainty in Fuvw1
102-106 F5.2 mag uvm2mag [11/12.2]? De-reddened Swift/UVOT uvm2 band
magnitude
108-111 F4.2 mag e_uvm2mag [0.03/0.2]? Uncertainty in uvm2mag
113-117 F5.2 mJy Fuvm2 [10.8/29.1]? De-reddened Swift/UVOT uvm2 band
flux density
119-122 F4.2 mJy e_Fuvm2 [0.1/0.5]? Uncertainty in Fuvm2
124-128 F5.2 mag uvw2mag [11/12]? De-reddened Swift/UVOT uvw2 band
magnitude
130-133 F4.2 mag e_uvw2mag [0.03/0.2]? Uncertainty in uvw2mag
135-139 F5.2 mJy Fuvw2 [11.7/28]? De-reddened Swift/UVOT uvw2 band
flux density
141-144 F4.2 mJy e_Fuvw2 [0.1/1.2]? Uncertainty in Fuvw2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.1 --- Sig [99.5/99.9] Intra-day Variability
Significance (1)
6- 16 I11 --- obsID1 [31202142/92204003] First observation
identifier (2)
18- 28 I11 --- obsID2 [35014107/92204004]? Last observation
identifier (2)
30- 32 A3 --- Orbit Orbit of obsID1, Or# (2)
34- 43 A10 "Y/M/D" Date1 UT Date of observation 1 (2)
45- 54 A10 "Y/M/D" Date2 UT Date of observation 2 (2)
56- 60 F5.2 h Exp [0.1/24] Total length of the particular
observation (2)
62- 69 F8.3 --- chi2 [1.9/3325.6] Reduced χ2 parameter
71- 72 I2 --- DOF [1/24] Fit degrees of freedom
74- 78 A5 --- ORS Orbit segment (2)
80- 84 F5.2 % Fvar [1.4/38.6] Fractional variability amplitude
86- 88 F3.1 % e_Fvar [0.2/1.4] Uncertainty in Fvar
90- 93 F4.2 --- aMin [1.7/2.6]? Min photon index at the energy E1
in LP model (3)
95-100 F6.2 --- e_aMin [0.01/0.3]? Uncertainty in aMin
102-105 F4.2 --- aMax [1.8/2.7]? Max photon index at the energy E1
in LP model (3)
107-110 F4.2 --- e_aMax [0.01/0.03]? Uncertainty in aMax
112-115 F4.2 --- GamMin [1.8/2.5]? Min photon index in PL model (3)
117-120 F4.2 --- e_GamMin [0.01/0.02]? Uncertainty in GammaMin
122-125 F4.2 --- GamMax [2/2.4]? Max photon index in PL model (3)
127-130 F4.2 --- e_GamMax [0.02]? Uncertainty in GammaMax
132-135 F4.2 --- bMin [0.08/0.4]? Min curvature parameter in LP model
137-140 F4.2 --- e_bMin [0.02/0.07]? Uncertainty in bMin
142-145 F4.2 --- bMax [0.1/0.5]? Max curvature parameter in LP model
147-150 F4.2 --- e_bMax [0.03/0.08]? Uncertainty in bMax
152-156 F5.3 keV EpMin [0.009/7.3]? Min position of the SED peak
in LP model
158-162 F5.3 keV e_EpMin [0.004/0.5]? Uncertainty in EpMin
164-167 F4.2 keV EpMax [0.09/9.2]? Max position of the SED peak
in LP model
169-172 F4.2 keV e_EpMax [0.03/0.7]? Uncertainty in EpMax
174-181 F8.3 --- HRMin [0.2/1.1]? Minimum hardness ratio
183-190 F8.3 --- e_HRMin [0.01/0.04]? Uncertainty in HRMin
192-198 F7.3 --- HRMax [0.2/1.2]? Maximum hardness ratio
200-204 F5.3 --- e_HRMax [0.009/0.2]? Uncertainty in HRMax
--------------------------------------------------------------------------------
Note (1): Intra-day 0.3-10keV variability (IDV), defined as a flux change with
99.9% confidence within a day (the threshold generally used for this
purpose; see, e.g., Andruchow+ 2005A&A...442...97A 2005A&A...442...97A) using the
χ2-statistics.
Confidences of 99.9 and 99.5 are given in the table.
Note (2): The total exposure used for intra-day 0.3-10keV variability (IDV)
calculations can segment a single obsID or span multiple obsIDs.
The columns that define the exposure for calculating IDVs are:
obsID1 = The first observation identifier;
obsID2 = The last observation identifier;
Or1 = Which orbit of obsID1 used for IDV;
Date1 = Min range of observation UT date;
Date2 = Max range of observation UT date;
Exp = Total exposure length in hours, including intervals between obsIDs;
ORS = That segment, in seconds, of Orbit or obsID1 used for IDV. If the
entire orbit was used then ORS = Orbit.
Note (3): When only one spectrum is available for the particular observation,
only a single value is provided for each spectral parameters instead
of a range.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 I11 --- obsID [31202141/94204006] Observation identifier
13- 25 A13 --- ORS Orbit/Segment code for model fit (G1)
27- 30 F4.2 --- a [1.7/2.7] Model parameter, photon index
at the energy E1
32- 35 F4.2 --- e_a [0.01/0.03] Uncertainty in a
37- 40 F4.2 --- b [0.08/0.5] Model parameter, curvature parameter
42- 45 F4.2 --- e_b [0.03/0.08] Uncertainty in b
47- 51 F5.3 keV Ep [0.005/9.2] Model parameter, position
of the SED peak
53- 57 F5.3 keV e_Ep [0.003/0.7] Uncertainty in Ep
59- 63 F5.3 --- K [0.06/1.8] Model parameter, normalization factor
65- 69 F5.3 --- e_K [0.001/0.04] Uncertainty in K
71- 75 F5.3 --- chi2 [0.8/1.2] Reduced χ^2 parameter
77- 79 I3 --- DOF [12/276] Fit degrees of freedom
81- 86 F6.3 [mW/m2] logFS [-9.7/-8.7] Log unabsorbed 0.3-2 keV Flux
88- 92 F5.3 [mW/m2] e_logFS [0.004/0.009] Uncertainty in logFS
94-100 F7.3 [mW/m2] logFH [-10.3/-0.1] Log unabsorbed 2-10 keV Flux
102-106 F5.3 [mW/m2] e_logFH [0.002/0.03] Uncertainty in logFH
108-113 F6.3 [mW/m2] logFT [-9.9/-8.5] Log unabsorbed 0.3-10 keV Flux
115-119 F5.3 [mW/m2] e_logFT [0.004/0.07] Uncertainty in logFH
121-125 F5.3 --- HR [0.2/1.2] Hardness ratio (G2)
127-131 F5.3 --- e_HR [0.008/0.2] Uncertainty in HR
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 I11 --- obsID [35014092/35014210] Observation identifier
13- 25 A13 --- ORS Orbit/Segment code for model fit (G1)
27- 30 F4.2 --- Gamma [1.8/2.8] Photon index in PL model
32- 35 F4.2 --- e_Gamma [0.01/0.02] Uncertainty in Gamma
37- 41 F5.3 --- K [0.04/0.5] Normalization
43- 47 F5.3 --- e_K [0.001/0.02] Uncertainty in K
49- 53 F5.3 --- chi2 [0.8/1.2] Reduced χ2 parameter
55- 57 I3 --- DOF [106/276] Fit degrees of freedom
59- 64 F6.3 [mW/m2] logFS [-9.8/-8.9] Log unabsorbed 0.3-2 keV Flux
66- 70 F5.3 [mW/m2] e_logFS [0.004/0.008] Uncertainty in logFS
72- 78 F7.3 [mW/m2] logFH [-10.4/-8.9] Log unabsorbed 2-10 keV Flux
80- 84 F5.3 [mW/m2] e_logFH [0.009/0.02] Uncertainty in logFH
86- 91 F6.3 [mW/m2] logFT [-9.7/-8.6] Log unabsorbed 0.3-10 keV Flux
93- 97 F5.3 [mW/m2] e_logFT [0.005/0.007] Uncertainty in logFH
99-103 F5.3 --- HR [0.2/1.1] Hardness ratio (G2)
105-109 F5.3 --- e_HR [0.009/0.04] Uncertainty in HR
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Global notes:
Note (G1): This column contains the "orbit" (Or#) and "segment" (S#) in seconds
(#s) of that orbit used in the fit.
Note (G2): Hardness ratio is calculated as a ratio of unabsorbed 2-10keV to
0.3-2keV fluxes.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-Jun-2018