J/ApJS/247/27 Swift obs. of Mrk 421. III. 2015 Dec-2018 Apr (Kapanadze+, 2020)
Swift observations of Mrk 421 in selected epochs.
III. Extreme X-ray timing/spectral properties and multiwavelength lognormality
during 2015 December-2018 April.
Kapanadze B., Gurchumelia A., Dorner D., Vercellone S., Romano P.,
Hughes P., Aller M., Aller H., Kharshiladze O.
<Astrophys. J. Suppl. Ser., 247, 27 (2020)>
=2020ApJS..247...27K 2020ApJS..247...27K
ADC_Keywords: Active gal. nuclei; X-ray sources; Ultraviolet; Optical;
Gamma rays
Keywords: Active galactic nuclei ; X-ray active galactic nuclei ; Galaxy jets ;
Extragalactic astronomy
Abstract:
We present the results from the timing and spectral study of Mrk 421
based mainly on the Swift data in the X-ray energy range obtained
during the time interval 2015 December-2018 April. The most extreme
X-ray flaring activity on long-term, daily, and intraday timescales
was observed during the 2 month period that started in 2017 December,
when the 0.3-10keV flux exceeded a level of 5x10-9erg/cm2/s,
recorded only twice previously. While the TeV- band and X-ray
variabilities were mostly correlated, the source often varied in a
complex manner in the MeV-GeV and radio-UV energy ranges, indicating
that the multifrequency emission of Mrk 421 could not always be
generated in a single zone. The longer-term flares at X-rays and
γ-rays showed a lognormal character, possibly indicating a
variability imprint of the accretion disk onto the jet. A vast
majority of the 0.3-10keV spectra were consistent with the
log-parabolic model, showing relatively low spectral curvature and
correlations between the different spectral parameters, predicted in
the case of the first- and second-order Fermi processes. The position
of the synchrotron spectral energy distribution peak showed an extreme
variability on diverse timescales between the energies Ep<0.1 and
>15keV, with 15% of the spectra peaking at the hard X-ray, and was
related to the peak height as Sp∝Epα with
α∼0.6, which is expected for the transition from Kraichnan-type
turbulence into the "hard sphere" one. The 0.3-300GeV spectra showed
features of the hadronic contribution, jet-star interaction, and
upscatter in the Klein-Nishina regime in different time intervals.
Description:
In this paper, we present the results of our detailed study of the
timing/spectral behavior of Mrk 421 during the 2015 December-2018
April Swift-XRT observations.
Using XRT observations, we checked correlations between the 0.3 and
10keV flux variability and those observed with different instruments:
the Ultraviolet/Optical Telescope (UVOT) and the Burst Alert Telescope
(BAT) on board Swift, the LAT on board Fermi, MAXI, the First G-APD
Cerenkov Telescope (FACT), the 40m telescope of the Owens Valley Radio
Observatory (OVRO) and the optical telescopes of Steward Observatory.
We retrieved the raw Swift-XRT data from NASA's Archive of Data on
Energetic Phenomena (HEASARC).
Objects:
------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------
11 04 27.31 +38 12 31.8 Mrk 421 = UGC 6132
------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 135 299 Summary of the XRT and UVOT observations in
the time interval 2015 December-2018 April
table4.dat 186 141 The 0.3-10keV intraday variabilities (IDVs)
during 2015 December-2018 April
table5.dat 56 44 The Optical-UV and γ-ray IDVs
during 2015 December-2018 April
table6.dat 126 886 Results of the Swift-XRT spectral analysis
with the log-parabolic model
table10.dat 99 94 Results of the XRT spectral analysis
with a simple power-law model
--------------------------------------------------------------------------------
See also:
B/swift : Swift Master Catalog (HEASARC, 2004-)
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/ApJS/197/24 : Chandra large-scale extragalactic jets. I. (Massaro+, 2011)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
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/A+A/593/A91 : Mrk 421 multi-wavelength variability, 2007-2009 (Ahnen+, 2016)
J/ApJ/831/102 : Swift and NuSTAR obs. of the BL Lac Mrk 421 (Kapanadze+, 2016)
J/ApJ/848/103 : ∼1.5yr Swift observations of Mrk 421 (Kapanadze+, 2017)
J/ApJ/854/66 : Swift observations of Mrk 421. I. 2005-2008 (Kapanadze+, 2018)
J/ApJ/858/68 : Mrk 421 Swift obs. in selected epochs. II. (Kapanadze+, 2018)
J/ApJS/238/13 : Spectral and timing results of 1ES 1959+650 (Kapanadze+, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- obsID [10474002/93249013] Swift observation
identifier
10- 19 A10 "Y/D/M" st.date UTC date of observation start
21- 28 A8 "h:m:s" st.time UTC time of observation start
30- 37 A8 "h:m:s" UTEnd UTC time of observation end
39- 40 I2 d UTOff [1]? Offset in days if UTEnd is
on a different UT Date
42- 50 F9.3 d MJD Modified Julian Date, observation start
52- 55 I4 s Exp [45/6021]? Exposure time
57- 62 F6.2 ct/s XRT [7/163]? Observation-binned
0.3-10keV count rate
64- 69 F6.2 ct/s e_XRT [0.08/1.5]? Uncertainty in XRT
71- 75 F5.2 mag uvw1mag [11/12.6]? De-reddened Swift/UVOT
uvw1 band magnitude
77- 80 F4.2 mag e_uvw1mag [0.03/0.2]? Uncertainty in uvw1mag
82- 86 F5.2 mJy Fuvw1 [8.4/30]? De-reddened Swift/UVOT
uvw1 band flux density
88- 91 F4.2 mJy e_Fuvw1 [0.04/1.3]? Uncertainty in Fuvw1
93- 97 F5.2 mag uvm2mag [11.2/13.1]? De-reddened Swift/UVOT
uvm2 band magnitude
99-102 F4.2 mag e_uvm2mag [0.03/0.2]? Uncertainty in uvm2mag
104-108 F5.2 mJy Fuvm2 [4.4/23.3]? De-reddened Swift/UVOT
uvm2 band flux density
110-113 F4.2 mJy e_Fuvm2 [0.09/0.5]? Uncertainty in Fuvm2
115-119 F5.2 mag uvw2mag [11/12.5]? De-reddened Swift/UVOT
uvw2 band magnitude
121-124 F4.2 mag e_uvw2mag [0.03/0.4]? Uncertainty in uvw2mag
126-130 F5.2 mJy Fuvw2 [7.6/26.3]? De-reddened Swift/UVOT
uvw2 band flux density
132-135 F4.2 mJy e_Fuvw2 [0.18/0.9]? Uncertainty in Fuvw2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 27 A27 --- obsID Observation identifier(s) (1)
29- 37 F9.3 d MJD Modified Julian Date, observation start
(JD-2400000.5)
39- 43 F5.2 h dt [0.1/24] Total length of the particular
observation (2)
45- 52 F8.2 --- chi2 [2.4/18089]? Reduced χ2 parameter
54- 55 I2 --- dof [1/18]? Fit degrees of freedom
57- 61 A5 --- Bin Orbit segment
63- 66 F4.1 % Fvar [1.5/57.2]? Fractional variability amplitude
68- 71 F4.1 % e_Fvar [0.2/4]? Uncertainty in Fvar
73- 76 F4.2 --- a-min [1.6/3]? Min log-parabolic parameter, a
78- 81 F4.2 --- e_a-min [0.01/0.04]? Uncertainty in a-min
83- 86 F4.2 --- a-max [1.7/2.9]? Max log-parabolic parameter, a
88- 91 F4.2 --- e_a-max [0.01/0.04]? Uncertainty in a-max
93- 96 F4.2 --- alpha-min [1.0/3]? Min power-law parameter, alpha
98-101 F4.2 --- e_alpha-min [0.01/0.03]? Uncertainty in alpha-min
103-106 F4.2 --- alpha-max [1.8/2.4]? Max power-law parameter, alpha
108-111 F4.2 --- e_alpha-max [0.01/0.08]? Uncertainty in alpha-max
113-116 F4.2 --- b-min [0.07/0.4]? Min curvature parameter
118-121 F4.2 --- e_b-min [0.04/0.09]? Uncertainty in b-min
123-126 F4.2 --- b-max [0.09/0.5]? Max curvature parameter
128-131 F4.2 --- e_b-max [0.03/0.2]? Uncertainty in b-max
133-137 F5.3 keV Ep-min [0.002/6.5]? Min position of the SED peak
139-145 F7.3 keV e_Ep-min [0.001/2]? Uncertainty in Ep-min
147-151 F5.2 keV Ep-max [0.02/14.7]? Max position of the SED peak
153-156 F4.2 keV e_Ep-max [0.01/1.7]? Uncertainty in Ep-max
158-161 F4.2 --- HR-min [0.1/1.1]? Minimum hardness ratio
163-166 F4.2 --- e_HR-min [0.01/0.03]? Uncertainty in HR-min
168-171 F4.2 --- HR-max [0.1/1.3]? Maximum hardness ratio
173-176 F4.2 --- e_HR-max [0.01/0.05]? Uncertainty in HR-max
178-186 A9 --- Remarks Remarks (3)
--------------------------------------------------------------------------------
Note (1): This column includes a range of obsIDs, and specific "orbit" (Or#)
subset(s).
Note (2): The total length of the particular observation includes the intervals
between the separate orbits.
Note (3): Remark related to the variable spectral parameter making the basic
contribution in the observed IDV. Code as follows:
1 = photon index;
2 = curvature;
3 = Ep;
4 = Sp;
5 = change in the particles' energy distribution from the log-parabolic
functional shape into the power-law one or vice versa.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 d MJDst MJD start date of observation
10 A1 --- --- [-]
11- 19 A9 d MJDEnd MJD end date of observation
21- 30 A10 --- Band Filter or energy range
32- 36 F5.2 h dt [3.2/23.6] Length of the observation ΔT
38- 42 F5.2 --- chi2 Rediced χ2 parameter
43 A1 --- --- [/]
44- 45 I2 --- dof Degree of freedom
47- 51 F5.2 % Fvar [3.5/57.6] Fractional variability amplitude
53- 56 F4.1 % e_Fvar [0.7/12.8] Uncertainty in Fvar
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- obsID [3422805/93249013] Observation identifier
10- 26 A17 --- ORS Orbit/Segment code for model fit (1)
27- 30 F4.2 --- a [1.6/3] Model parameter, photon index
at the energy E1
32- 35 F4.2 --- e_a [0.01/0.06] Uncertainty in a
37- 40 F4.2 --- b [0.07/0.5] Model parameter, curvature parameter
42- 45 F4.2 --- e_b [0.03/0.3] Uncertainty in b
47- 52 F6.3 keV Ep [0.002/14.7] Model parameter,
position of the SED peak
54- 58 F5.3 keV e_Ep [0.001/1.7] Uncertainty in Ep
60- 63 F4.2 --- 10K [0.3/9.4] Model parameter,
normalization factor, x10
65- 68 F4.2 --- e_10K [0.01/0.2] Uncertainty in K
70- 76 F7.3 --- chi2 [0.8/1.2] Reduced χ2 parameter
78- 80 I3 --- dof [59/292] Fit degrees of freedom
82- 87 F6.2 [mW/m2] logFS [12.9/269] Log unabsorbed 0.3-2keV flux
89- 92 F4.2 [mW/m2] e_logFS [0.2/3.8] Uncertainty in logFS
94- 99 F6.2 [mW/m2] logFH [2.3/291] Log unabsorbed 2-10keV flux
101-104 F4.2 [mW/m2] e_logFH [0.09/8] Uncertainty in logFH
106-111 F6.2 [mW/m2] logFT [15.4/536] Log unabsorbed 0.3-10keV flux
113-116 F4.2 [mW/m2] e_logFT [0.3/8.6] Uncertainty in logFH
118-121 F4.2 --- HR [0.1/1.3] Hardness ratio (2)
123-126 F4.2 --- e_HR [0.01/0.05] Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): This column contains the "orbit" (Or#) and "segment" (S#) in seconds
[#s] of that orbit used in the fit.
Note (2): Hardness ratio is calculated as a ratio of unabsorbed 2-10 keV to
0.3-2 keV fluxes.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- obsID [31202143/93249013] Observation identifier
10- 24 A15 --- ORS Orbit/Segment code for model (1)
26- 29 F4.2 --- Gamma [1.7/3] Photon index in PL model
31- 34 F4.2 --- e_Gamma [0.01/0.05] Uncertainty in Gamma
36- 39 F4.2 --- K [0.4/10] Normalization
41- 44 F4.2 --- e_K [0.01/0.09] Uncertainty in K
46- 49 F4.2 --- chi2 [0.8/1.2] Reduced χ2 parameter
51- 53 I3 --- dof [68/272] Fit degrees of freedom
55- 60 F6.2 [mW/m2] logFS [16.8/250] Log unabsorbed 0.3-2keV Flux
62- 65 F4.2 [mW/m2] e_logFS [0.2/3.3] Uncertainty in logFS
67- 72 F6.2 [mW/m2] logFH [4/267] Log unabsorbed 2-10keV Flux
74- 77 F4.2 [mW/m2] e_logFH [0.1/6] Uncertainty in logFH
79- 84 F6.2 [mW/m2] logFT [10/506] Log unabsorbed 0.3-10keV Flux
86- 89 F4.2 [mW/m2] e_logFT [0.3/7] Uncertainty in logFH
91- 94 F4.2 --- HR [0.1/1.3] Hardness ratio (2)
96- 99 F4.2 --- e_HR [0.01/0.05] Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): This column contains the "orbit" (Or#) and "segment" (S#) in seconds
[#s] of that orbit used in the fit.
Note (2): Hardness ratio is calculated as a ratio of unabsorbed 2-10 keV to
0.3-2 keV fluxes.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Kapanadze et al. Paper I. 2018ApJ...854...66K 2018ApJ...854...66K Cat. J/ApJ/854/66
Kapanadze et al. Paper II. 2018ApJ...858...68K 2018ApJ...858...68K Cat. J/ApJ/858/68
Kapanadze et al. Paper III. 2020ApJS..247...27K 2020ApJS..247...27K This Catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Jun-2020