J/ApJ/831/102 Swift and NuSTAR obs. of the BL Lac Mrk 421 (Kapanadze+, 2016)
X-ray flaring activity of Mrk 421 in the first half of 2013.
Kapanadze B., Dorner D., Vercellone S., Romano P., Aller H., Aller M.,
Hughes P., Reynolds M., Kapanadze S., Tabagari L.
<Astrophys. J., 831, 102-102 (2016)>
=2016ApJ...831..102K 2016ApJ...831..102K (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; X-ray sources ; Ultraviolet
Keywords: BL Lacertae objects: Markarian 421
Abstract:
We present the results of the Swift and NuSTAR observations of the
nearby BL Lac object Mrk 421 during 2013 January-June. The source
exhibited a strong long-term variability in the 0.3-10keV and 3-79keV
bands with the maximum-to-minimum daily-binned flux ratios of 22 and
95, respectively, in about 3 months, mainly due to unprecedented
strong X-ray outbursts by more than an order of magnitude in both
bands within 2 weeks in 2013 April when the 0.3-10keV count rate
exceeded the level of 200cts/s for the first time, and Mrk 421 became
one of the brightest sources in the X-ray sky. The source was also
very active on intra-day timescales, and it showed flux doubling and
halving timescales of 1.16-7.20hr and 1.04-3.54hr, respectively. On
some occasions, the flux varied by 4%-23% within 300-840s. During this
period, the source also exhibited some of the most extreme X-ray
spectral variability ever reported for BL Lacs-the location of the
synchrotron spectral energy distribution peak shifted from a few eV to
∼10keV, and the photon index at 1 keV and curvature parameter varied
on timescales from a few weeks down to intervals shorter than 1ks.
MAGIC and First G-APD Cherenkov Telescope observations also revealed a
very strong very high energy (VHE) flare during April 11-17. The UV
and HE γ-ray flares were much weaker compared to their X-ray
counterparts, and they generally showed significantly stronger
correlation with each other than with the X-ray fluxes.
Description:
We retrieved the Swift-XRT data from the publicly available archive,
maintained by HEASARC. We present the results of X-ray observations of
the high-energy peaked BL Lac (HBL) source Mrk421 performed by
Swift-XRT and NuSTAR during 2013 January-June.
Along with the 0.3-10keV and 3-79keV data obtained with the Swift-XRT
and NuSTAR instruments, we have processed and analyzed those obtained
with the Ultraviolet-Optical Telescope (UVOT) and Large Area Telescope
(LAT) onboard Fermi. We have also used the publicly available light
curves from the observations performed with the Burst Alert Telescope
(BAT) onboard Swift, Monitor of All Sky X-ray Image (MAXI), MAGIC,
First G-APD Cherenkov Telescope (FACT), and the OVRO 40m telescope
during the 2013 January-June period to draw conclusions about the
interband correlations.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
11 04 27.31 +38 12 31.8 Mrk 421 = SWIFT J1104.5+3812
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 132 68 Summary of the XRT and UVOT observations
table2.dat 68 23 Summary of the NuSTAR observations
table3.dat 131 47 Summary of intra-day X-ray variabilities (IDVs) from
the XRT and NuSTAR observations
table5.dat 131 93 Summary of sub-hour X-ray variability
table6.dat 136 328 Summary of the XRT spectral analysis with the
log-parabolic (LP) model
table9.dat 115 59 Summary of the XRT spectral analysis with a simple
power-law (PL) model
table10.dat 129 251 Summary of the NuSTAR spectral analysis with
the LP model
table11.dat 115 22 Summary of the NuSTAR spectral analysis with a simple
PL model
--------------------------------------------------------------------------------
See also:
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/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/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/ApJ/722/520 : Gamma-ray light curves of Fermi blazars (Abdo+, 2010)
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- 8 I8 --- obsID Observation identifier (1)
10- 19 A10 "Y/M/D" St.date Date of the observation start; UTC
(year 2013 added by CDS)
21- 28 A8 "h:m:s" St.time Time of the observation start; UTC
30- 39 A10 "Y/M/D" End.date Date of the observation end; UTC
(year 2013 added by CDS)
41- 48 A8 "h:m:s" End.time Time of the observation end; UTC
50- 54 I5 s Exp [84/10263] Exposure time
56- 61 F6.2 ct/s CR [7/163] Swift/XRT count rate
63- 66 F4.2 ct/s e_CR [0.04/0.8] Uncertainty in CR
68- 72 F5.2 mag uvw1mag [10.5/11.8]? De-reddened Swift/UVOT uvw1 band
magnitude
74- 77 F4.2 mag e_uvw1mag [0.03/0.08]? Uncertainty in uvw1mag
79- 83 F5.2 mJy Fuvw1 [16.9/52]? De-reddened Swift/UVOT uvw1 band
flux density
85- 88 F4.2 mJy e_Fuvw1 [0.5/3]? Uncertainty in Fuvw1
90- 94 F5.2 mag uvm2mag [10.5/12]? De-reddened Swift/UVOT uvm2 band
magnitude
96- 99 F4.2 mag e_uvm2mag [0.03/0.08]? Uncertainty in uvm2mag
101-105 F5.2 mJy Fuvm2 [15.3/47]? De-reddened Swift/UVOT uvm2 band
flux density
107-110 F4.2 mJy e_Fuvm2 [0.2/2]? Uncertainty in Fuvm2
112-116 F5.2 mag uvw2mag [10.5/12]? De-reddened Swift/UVOT uvw2 band
magnitude
118-121 F4.2 mag e_uvw2mag [0.03/0.08]? Uncertainty in uvw2mag
123-127 F5.2 mJy Fuvw2 [15/46.5]? De-reddened Swift/UVOT uvw2 band
flux density
129-132 F4.2 mJy e_Fuvw2 [0.4/3]? Uncertainty in Fuvw2
--------------------------------------------------------------------------------
Note (1): The three leading zeroes are omitted.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 I11 --- obsID Observation identifier
13- 22 A10 "Y/M/D" St.date Date of the observation start; UTC
(year 2013 added by CDS)
24- 31 A8 "h:m:s" St.time Time of the observation start; UTC
33- 42 A10 "Y/M/D" End.date Date of the observation end; UTC
(year 2013 added by CDS)
44- 51 A8 "h:m:s" End.time Time of the observation end; UTC
53- 57 I5 s Exp Exposure time
59- 63 F5.2 ct/s CR NuSTAR count rate
65- 68 F4.2 ct/s e_CR Uncertainty in CR
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table[35].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Fac Facility identifier (NuSTAR or XRT)
8- 29 A22 --- obsID Observation identifier
31- 35 F5.2 h Dur [0.4/23.5] Observed duration
37- 42 F6.2 --- chi2 [1/460] Reduced Χ2 of fit
44- 46 I3 --- DOF [4/392] Degrees of Freedom in fit
48- 50 I3 s Bin [30/120] Bin width
52- 57 F6.3 % Fvar [1/47.5] Fraction rms variability amplitude
59- 63 F5.3 % e_Fvar [0.06/5.2] Uncertainty in Fvar
65- 68 F4.2 --- Dela1 [1.6/3.2]? Range of photon index at 1keV;
first orbit
70- 73 F4.2 --- e_Dela1 [0.01/0.2]? Uncertainty in Dela1
75- 78 F4.2 --- Dela2 [0.2/3.1]? Range of photon index at 1keV;
second orbit
80- 83 F4.2 --- e_Dela2 [0.01/0.05]? Uncertainty in Dela2
85- 89 F5.2 --- Delb1 [-0.3/0.5]? Curvature parameter; first orbit
91- 95 F5.3 --- e_Delb1 [0.01/0.2]? Uncertainty in Delb1
97-100 F4.2 --- Delb2 [0.1/0.6]? Curvature parameter; second orbit
102-105 F4.2 --- e_Delb2 [0.02/0.2]? Uncertainty in Delb2
107-112 F6.3 keV DelEp1 [0.001/10]? Position of synchrotron SED;
first orbit
114-118 F5.3 keV e_DelEp1 [0.002/2.2]? Uncertainty in DelEp1
120-125 F6.3 keV DelEp2 [0.04/10]? Position of synchrotron SED;
second orbit
127-131 F5.3 keV e_DelEp2 [0.01/2.4]? Uncertainty in DelEp2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- obsID Observation identifier
26- 29 F4.2 --- a [1/2.9] Photon index at 1kev
31- 34 F4.2 --- e_a [0.01/0.05] Uncertainty in a
36- 39 F4.2 --- b [0.09/0.5] Curvature parameter
41- 44 F4.2 --- e_b [0.02/0.2] Uncertainty in b
46- 51 F6.3 keV Ep [0.003/10] Position of synchrotron SED
53- 57 F5.3 keV e_Ep [0.001/2.2] Uncertainty in Ep
59- 64 F6.4 --- K [0.01/1.1] Normalization
66- 71 F6.4 --- e_K [0.0009/0.02] Uncertainty in K
73- 79 F7.4 --- chi2 [0.8/1.4] Reduced Χ2 of fit
81- 83 I3 --- DOF [69/475] Degrees of Freedom of fit
84- 84 A1 --- u_DOF [?] Uncertainty flag in DOF
86- 91 F6.3 [mW/m2] logFS [-10/-8.5] Log unabsorbed soft (0.3-2keV)
flux (in units of erg/s/cm2)
93- 97 F5.3 [mW/m2] e_logFS [0.002/0.05] Uncertainty in logFS
99-105 F7.3 [mW/m2] logFH [-10.6/9] Log unabsorbed hard (2-10keV)
flux (in units of erg/s/cm2)
107-111 F5.3 [mW/m2] e_logFH [0.005/0.2] Uncertainty in logFH
113-118 F6.3 [mW/m2] logFT [-9.9/-8.2] Log unabsorbed total (0.3-10keV)
flux (in units of erg/s/cm2)
120-124 F5.3 [mW/m2] e_logFT [0.002/0.09] Uncertainty in logFT
126-130 F5.3 --- HR [0.1/1.3] Hardness ratio (1)
132-136 F5.3 --- e_HR [0.005/0.04] Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): Where HR is the ratio of the unabsorbed 2-10keV to 0.3-2keV fluxes.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 28 A28 --- obsID Observation identifier
30- 33 F4.2 --- Gamma Photon index
35- 39 F5.3 --- e_Gamma Uncertainty in Gamma
41- 45 F5.3 --- K Normalization
47- 51 F5.3 --- e_K Uncertainty in K
53- 57 F5.3 --- chi2 Reduced Χ2 of fit
59- 61 I3 --- DOF Degrees of Freedom of fit
63- 69 F7.3 [mW/m2] logFS Log unabsorbed soft (0.3-2 keV) flux (1)
71- 75 F5.3 [mW/m2] e_logFS Uncertainty in logFS
77- 83 F7.3 [mW/m2] logFH Log unabsorbed hard (2-10 keV) flux (1)
85- 89 F5.3 [mW/m2] e_logFH Uncertainty in logFH
91- 97 F7.3 [mW/m2] logFT Log unabsorbed total (0.3-10 keV) flux (1)
99-103 F5.3 [mW/m2] e_logFT Uncertainty in logFT
105-109 F5.3 --- HR Hardness ratio (2)
111-115 F5.3 --- e_HR Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): In units of erg/s/cm2.
Note (2): Where HR is the ratio of the unabsorbed 2-10keV to 0.3-2keV fluxes.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- obsID Observation identifier
21- 24 F4.2 --- a [2.2/3.2] Photon index at 1kev
26- 30 F5.3 --- e_a [0.006/0.06] Uncertainty in a
32- 35 F4.2 --- b [0.1/0.6] Curvature parameter
37- 40 F4.2 --- e_b [0/0.2] Uncertainty in b
42- 46 F5.3 keV Ep [0.001/4.4] Position of synchrotron SED
48- 52 F5.3 keV e_Ep [0.002/0.9]? Uncertainty in Ep
54- 59 F6.3 --- K [0.03/11] Normalization
61- 64 F4.2 --- e_K [0.01/0.4] Uncertainty in K
66- 71 F6.3 --- chi2 [0.8/11] Reduced Χ2 of fit
73- 75 I3 --- DOF [158/952] Degrees of Freedom of fit
77- 83 F7.3 [mW/m2] logFS [-10.2/10.1] Log unabsorbed soft (3-10keV)
flux (in units of erg/s/cm2)
85- 89 F5.3 [mW/m2] e_logFS [0.001/0.04] Uncertainty in logFS
91- 97 F7.3 [mW/m2] logFH [-10.8/-8.6] Log unabsorbed hard (10-79keV)
flux (in units of erg/s/cm2)
99-103 F5.3 [mW/m2] e_logFH [0.004/0.04] Uncertainty in logFH
105-111 F7.3 [mW/m2] logFT [-10.1/-8.3] Log unabsorbed total (3-79keV)
flux (in units of erg/s/cm2)
113-117 F5.3 [mW/m2] e_logFT [0.002/0.02] Uncertainty in logFT
119-123 F5.3 --- HR [0.2/1.1] Hardness ratio (1)
125-129 F5.3 --- e_HR [0.006/0.06] Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): Where HR is the ratio of the unabsorbed 10-79keV to 3-10keV fluxes.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 28 A28 --- obsID Observation identifier
30- 33 F4.2 --- Gamma Photon index
35- 39 F5.3 --- e_Gamma Uncertainty in Gamma
41- 45 F5.3 --- K Normalization
47- 51 F5.3 --- e_K Uncertainty in K
53- 57 F5.3 --- chi2 Reduced Χ2 of fit
59- 61 I3 --- DOF Degrees of Freedom of fit
63- 69 F7.3 [mW/m2] logFS Log unabsorbed soft (3-10 keV) flux (1)
71- 75 F5.3 [mW/m2] e_logFS Uncertainty in logFS
77- 83 F7.3 [mW/m2] logFH Log unabsorbed hard (10-79) keV flux (1)
85- 89 F5.3 [mW/m2] e_logFH Uncertainty in logFH
91- 97 F7.3 [mW/m2] logFT Log unabsorbed total (3-79 keV) flux (1)
99-103 F5.3 [mW/m2] e_logFT Uncertainty in logFT
105-109 F5.3 --- HR Hardness ratio (2)
111-115 F5.3 --- e_HR Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): In units of erg/s/cm2.
Note (2): Where HR is the ratio of the unabsorbed 10-79keV to 3-10keV fluxes.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 31-Jan-2017