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J/ApJS/232/17   Spectral properties of magnetar bursts   (Kirmizibayrak+, 2017)

Broadband spectral investigations of magnetar bursts. Kirmizibayrak D., Sasmaz Mus S., Kaneko Y., Gogus E. <Astrophys. J. Suppl. Ser., 232, 17-17 (2017)> =2017ApJS..232...17K (SIMBAD/NED BibCode)
ADC_Keywords: Pulsars ; X-ray sources Keywords: stars: individual: (SGR J1550-5418, SGR 1900+14, SGR 1806-20); stars: magnetars; stars: neutron; X-rays: bursts Abstract: We present our broadband (2-250keV) time-averaged spectral analysis of 388 bursts from SGR J1550-5418, SGR 1900+14, and SGR 1806-20 detected with the Rossi X-ray Timing Explorer (RXTE) here and as a database in a companion web-catalog. We find that two blackbody functions (BB+BB), the sum of two modified blackbody functions (LB+LB), the sum of a blackbody function and a power-law function (BB+PO), and a power law with a high-energy exponential cutoff (COMPT) all provide acceptable fits at similar levels. We performed numerical simulations to constrain the best fitting model for each burst spectrum and found that 67.6% of burst spectra with well-constrained parameters are better described by the Comptonized model. We also found that 64.7% of these burst spectra are better described with the LB+LB model, which is employed in the spectral analysis of a soft gamma repeater (SGR) for the first time here, than with the BB+BB and BB+PO models. We found a significant positive lower bound trend on photon index, suggesting a decreasing upper bound on hardness, with respect to total flux and fluence. We compare this result with bursts observed from SGR and AXP (anomalous X-ray pulsar) sources and suggest that the relationship is a distinctive characteristic between the two. We confirm a significant anticorrelation between burst emission area and blackbody temperature, and find that it varies between the hot and cool blackbody temperatures differently than previously discussed. We expand on the interpretation of our results in the framework of a strongly magnetized neutron star. Description: For our broadband spectral investigations, we used data collected with the RXTE mission, which was operational for ∼16yr from 1995 December until the end of 2011. SGR J1550-5418 bursts included in our study were sampled from 179 pointed RXTE observations that were performed between 2008 October and 2010 April. SGR 1900+14 bursts were among 432 RXTE observations between 1998 June and 2010 December. SGR 1806-20 bursts were observed between 1996 November and 2011 June with a total of 924 pointed RXTE observations. We used data collected from the Proportional Counter Array (PCA) and High Energy X-ray Timing Experiment (HEXTE) instruments carried on board RXTE. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 62 42 Observations of bursts for SGR J1550-5418 table2.dat 62 125 Observations of bursts for SGR 1900+14 table3.dat 62 221 Observations of bursts for SGR 1806-20 table5.dat 231 125 Spectral properties of SGR 1900+14 bursts table6.dat 231 221 Spectral properties of SGR 1806-20 bursts table7.dat 231 42 Spectral properties of SGR J1550-5418 bursts table9.dat 79 5 Results of single and broken power-law fits with corresponding flux intervals
See also: B/psr : ATNF Pulsar Catalogue (Manchester+, 2005) J/ApJ/634/L89 : 4.8GHz observations of SGR 1806-20 (Gelfand+, 2005) Byte-by-byte Description of file: table[123].dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq [1/221] Burst ID 5 A1 --- f_Seq Saturated bursts are marked with asterisk 7- 19 F13.3 --- TstartMET Burst Start Time, in MET 21- 39 A19 --- TstartUT Burst Start Time, in UTC 41- 46 F6.4 s TExp [0.08/6.6] Spectrum duration, TExp (1) 48- 62 A15 --- ObsID Observation ID
Note (1): TExp refers the duration of spectral extraction interval.
Byte-by-byte Description of file: table[567].dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq [1/221] Burst ID 5- 7 F3.1 keV bbkt1 [0.5/4]? BB+BB kT 1 (1) 9- 12 F4.2 keV E_bbkt1 ? BB+BB kT 1 upper bound error (2) 14- 17 F4.2 keV e_bbkt1 ? BB+BB kT 1 lower bound error (2) 19- 22 F4.1 keV bbkt2 [3.2/60]? BB+BB kT 2 (1) 24- 27 F4.1 keV E_bbkt2 ? BB+BB kT 2 upper bound error (2) 29- 32 F4.1 keV e_bbkt2 ? BB+BB kT 2 lower bound error (2) 34- 39 F6.2 --- bbchi [0.01/251]? BB+BB chi-squared statistic (1) 41- 43 I3 --- bbdof [1/131]? BB+BB DOF (3) 45- 52 F8.4 keV bpkt [0.0001/200]? BB+PO kT (1) 54- 58 F5.1 keV E_bpkt ? BB+PO kT upper bound error (2) 60- 67 F8.4 keV e_bpkt ? BB+PO kT lower bound error (2) 69- 73 F5.2 --- bppho [-3/4.5]? BB+PO power law photon index (1) 75- 78 F4.2 --- E_bppho ? BB+PO power law photon index upper bound error (2) 80- 83 F4.2 --- e_bppho ? BB+PO power law photon index lower bound error (2) 85- 90 F6.2 --- bpchi [0.1/236]? BB+PO chi-squared statistic (1) 92- 94 I3 --- bpdof [1/131]? BB+PO DOF (3) 96- 98 F3.1 keV lbkt1 [0.5/5]? LB+LB kT 1 (1) 100-102 F3.1 keV E_lbkt1 ? LB+LB kT 1 upper bound error (2) 104-106 F3.1 keV e_lbkt1 ? LB+LB kT 1 lower bound error (2) 108-111 F4.1 keV lbkt2 [3.5/60]? LB+LB kT 2 (1) 113-116 F4.1 keV E_lbkt2 ? LB+LB kT 2 upper bound error (2) 118-121 F4.1 keV e_lbkt2 ? LB+LB kT 2 lower bound error (2) 123-128 F6.2 --- lbchi [0.02/157]? LB+LB chi-squared statistic (1) 130-132 I3 --- lbdof [1/131]? LB+LB DOF (3) 134-138 F5.1 keV cpthcut [2/500]? COMPT cut-off energy (1) 140-144 F5.1 keV E_cpthcut ? COMPT cut-off energy upper bound error (2) 146-150 F5.1 keV e_cpthcut ? COMPT cut-off energy lower bound error (2) 152-156 F5.2 --- cptpho [-2/2]? COMPT power law photon index (1) 158-161 F4.2 --- E_cptpho ? COMPT power law photon index upper bound error (2) 163-166 F4.2 --- e_cptpho ? COMPT power law photon index lower bound error (2) 168-173 F6.2 --- cptchi [0.1/229]? COMPT chi-squared statistic (1) 175-177 I3 --- cptdof [3/133]? COMPT DOF (3) 179-186 E8.5 mW/m2 cptpcaflux ? COMPT PCA Flux (4) 188-195 E8.5 mW/m2 E_cptpcaflux ? COMPT PCA Flux Upper bound error (2) 197-204 E8.5 mW/m2 e_cptpcaflux ? COMPT PCA Flux Lower bound error (2) 206-213 E8.5 mW/m2 cpthxtflux ? COMPT HEXTE Flux (5) 215-222 E8.5 mW/m2 E_cpthxtflux ? COMPT HEXTE Flux Upper bound error (2) 224-231 E8.5 mW/m2 e_cpthxtflux ? COMPT HEXTE Flux Lower bound error (2)
Note (1): In our broadband spectral analysis, we used four models, three of which have been commonly used in describing short magnetar bursts in previous studies: the sum of two blackbody functions (BB+BB), the sum of a blackbody model and a power-law model (BB+PO), and a Comptonized model (COMPT). Additionally, we employed the sum of two modified blackbody functions (LB+LB) as set forth by Lyubarsky (2002MNRAS.332..199L). See section 3. Note (2): All errors are reported at 1 sigma Note (3): The number of free parameters are the same for BB+BB, BB+PO and LB+LB models and is 4 for each model and 6 for PCA and HEXTE joint spectral analysis. The number of free parameters is 3 for the COMPT model and is 4 in joint spectral analysis. See Section 3 for a list of free model parameters. Note (4): PCA Flux Energy Range: 2-30 keV Note (5): HEXTE Flux Energy Range: 15-250 keV
Byte-by-byte Description of file: table9.dat
Bytes Format Units Label Explanations
1- 14 A14 --- Name Soft gamma repeater (SGR) name 16- 27 A12 [10-3W/m2] logFlux log10 flux interval in erg/cm2/s 29- 33 F5.2 keV loEnergy [-7.6/-3.5] Low-energy index, broken power law 35- 38 F4.2 keV e_loEnergy loEnergy uncertainty 40- 44 F5.2 keV hiEnergy [-5.6/-3.4] High-energy index, broken power law 46- 49 F4.2 keV e_hiEnergy HiEnergy uncertainty 51- 54 F4.2 keV kTbk [5.2/8.1] The break index in kT 56- 59 F4.2 --- Chi2 [0.4/2.2] χ2/DOF; broken power law 61- 65 F5.2 --- Index [-3.6/-3.2] Single power law index 67- 70 F4.2 --- e_Index Index uncertainty 72- 75 F4.2 --- Chi2s [0.5/3] χ2/DOF; single power law 77- 79 I3 --- Nb Number of bursts; column added by CDS
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Oct-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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