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. =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 {gamma}-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: -------------------------------------------------------------------------------- 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 {Chi}^2^ 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 {Chi}^2^ 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/cm^2^) 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/cm^2^) 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/cm^2^) 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 {Chi}^2^ 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/cm^2^. 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 {Chi}^2^ 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/cm^2^) 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/cm^2^) 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/cm^2^) 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 {Chi}^2^ 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/cm^2^. 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