J/ApJ/852/53 Early X-ray flares in GRBs (Ruffini+, 2018)
Early X-ray flares in GRBs.
Ruffini R., Wang Y., Aimuratov Y., de Almeida U.B., Becerra L., Bianco C.L.,
Chen Y.C., Karlica M., Kovacevic M., Li L., Fuksman J.D.M., Moradi R.,
Muccino M., Penacchioni A.V., Pisani G.B., Primorac D., Rueda J.A.,
Shakeri S., Vereshchagin G.V., Xue S.-S.
<Astrophys. J., 852, 53 (2018)>
=2018ApJ...852...53R 2018ApJ...852...53R
ADC_Keywords: GRB; X-ray sources; Redshifts
Keywords: binaries: general ; black hole physics ; gamma-ray burst: general ;
hydrodynamics ; stars: neutron ; supernovae: general
Abstract:
We analyze the early X-ray flares in the GRB "flare-plateau-afterglow"
(FPA) phase observed by Swift-XRT. The FPA occurs only in one of the
seven GRB subclasses: the binary-driven hypernovae (BdHNe). This
subclass consists of long GRBs with a carbon-oxygen core and a neutron
star (NS) binary companion as progenitors. The hypercritical accretion
of the supernova (SN) ejecta onto the NS can lead to the gravitational
collapse of the NS into a black hole. Consequently, one can observe a
GRB emission with isotropic energy Eiso≳1052erg, as well as the
associated GeV emission and the FPA phase. Previous work had shown
that gamma-ray spikes in the prompt emission occur at ∼1015-1017cm
with Lorentz Gamma factors Γ∼102-103. Using a novel data
analysis, we show that the time of occurrence, duration, luminosity,
and total energy of the X-ray flares correlate with Eiso. A crucial
feature is the observation of thermal emission in the X-ray flares
that we show occurs at radii ∼1012cm with Γ≲4. These
model-independent observations cannot be explained by the "fireball"
model, which postulates synchrotron and inverse-Compton radiation from
a single ultrarelativistic jetted emission extending from the prompt
to the late afterglow and GeV emission phases. We show that in BdHNe a
collision between the GRB and the SN ejecta occurs at ∼1010cm,
reaching transparency at ∼1012cm with Γ≲4. The agreement
between the thermal emission observations and these theoretically
derived values validates our model and opens the possibility of
testing each BdHN episode with the corresponding Lorentz Gamma factor.
Description:
The discovery of GRBs by the Vela satellites was presented at the AAAS
meeting in February 1974 in San Francisco (Gursky & Ruffini
1975ASSL...48.....G 1975ASSL...48.....G). The Vela satellites were operating in gamma-rays
in the 150-750keV energy range and only marginally in X-rays.
Since 1991, the BATSE detectors on the Compton Gamma-Ray Observatory
(CGRO) have been leading to the classification of GRBs on the basis of
their spectral hardness and of their observed T90 duration in the
50-300keV energy band.
The BeppoSAX satellite, operating since 1996, joined the expertise of
the X-ray and gamma-ray communities. Its gamma-ray burst monitor
(GRBM) operating in the 40-700keV energy band determined the trigger
of the GRB, and two wide-field cameras operating in the 2-30keV X-ray
energy band allowed the localization of the source within an arcminute
resolution.
The Swift Burst Alert Telescope (BAT), operating in the 15-150keV
energy band, can detect GRB prompt emissions and accurately determine
their position in the sky within 3 arcmin. Within 90s, Swift can
re-point the narrow-field X-ray telescope (XRT), operating in the
0.3-10keV energy range, and relay the burst position to the ground.
Thanks to the Swift satellite, the number of detected GRBs increased
rapidly to 480 sources with known redshifts.
We have used Swift-XRT data in differentiating two distinct subclasses
of long GRBs: X-ray flares (XRFs) with Eiso≲1052erg and
binary-driven hypernovae (BdHNe) with Eiso≳1052erg (see Section 3).
Finally, the Fermi satellite, launched in 2008, detects ultrahigh
energy photons from 20MeV to 300GeV with the Large Area Telescope
(LAT) and detects photons from 8keV to 30MeV with the Gamma-ray Burst
Monitor (GBM). For the purposes of this article addressing long GRBs,
the Fermi observations have been prominent in further distinguishing
between XRFs and BdHNe.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 99 16 GRB sample properties of the prompt and flare phases
table5.dat 46 16 GRB sample properties of the prompt and
"flare-plateau-afterglow" (FPA) phases
table7.dat 45 16 Radii and temperatures of the thermal components
detected within the flare duration Δt
table9.dat 67 345 *List of the binary-driven hypernovae (BdHNe)
considered in this work
refs.dat 38 9 References
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Note on table9.dat: It is composed of 345 sources spanning 12 years of
Swift/XRT observation activity.
Out of the 345 BdHNe, there are 211 that have complete Swift-XRT observations,
and among them, there are 16 BdHNe with a well-determined early X-ray flare
structure.
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See also:
B/swift : Swift Master Catalog (HEASARC, 2004-)
IX/51 : GRB list (1990-2014) (Ruggeri+, 2016)
J/A+A/427/87 : List of GRBs (Gorosabel+, 2004)
J/A+A/448/L9 : Position catalogue of Swift XRT afterglows (Moretti+, 2006)
J/A+A/455/813 : BeppoSAX cat. of GRB X-ray afterglows (De Pasquale+, 2006)
J/AJ/133/1027 : Positions for 179 Swift X-ray afterglows (Butler+, 2007)
J/ApJ/690/163 : The first Swift UV-Opt GRB afterglow catalog (Roming+, 2009)
J/ApJ/701/824 : Afterglows of short & long-duration GRBs (Nysewander+, 2009)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/PAZh/35/10 : Gamma-ray bursts with known redshifts (Badjin+, 2009)
J/A+A/528/A122 : SwiftFT catalog (Puccetti+, 2011)
J/ApJ/746/156 : Radio afterglow observations of GRBs (Chandra+, 2012)
J/MNRAS/428/729 : GRB Swift X-ray light curves analysis (Margutti+, 2013)
J/ApJS/209/20 : Swift GRB catalog with X-ray data (Grupe+, 2013)
J/ApJ/787/66 : Burst duration measurements for a GRB sample (Zhang+, 2014)
J/ApJ/788/30 : Gamma-ray burst flares: X-ray flaring (Swenson+, 2014)
J/ApJ/807/76 : 373 GRBs between 0.008<z<6.7 (Li+, 2015)
J/A+A/581/A125 : UV/Optical/NIR spectroscopy GRB hosts (Kruehler+, 2015)
J/A+A/582/A111 : List of 389 GRBs (Li+, 2015)
J/A+A/584/A48 : New redshifts of 357 GBBs (Horvath+, 2015)
J/A+A/589/A97 : GRBs Ep and Fourier PDS slope correlation (Dichiara+, 2016)
J/ApJ/826/45 : GRB X-ray afterglows light curves analysis (Racusin+, 2016)
J/ApJS/227/7 : Long + short GRBs with host galaxies data (Li+, 2016)
J/ApJS/224/20 : 10yr of Swift/XRT obs. of GRBs (Yi+, 2016)
J/MNRAS/464/4545 : GRBs detected by Swift (2004-2015) (Buchner+, 2017)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB GRB identifier
9- 14 F6.4 --- z [0.8/4.2] Cosmological redshift z
16- 20 F5.2 s T90 [7.2/68.6] T90 in the rest frame
22- 28 E7.3 10-7J Eiso [9.5e+51/1.9e+54] GRB isotropic energy Eiso
30- 36 E7.3 10-7J e_Eiso [1.7e+51/7.7e+53] Eiso uncertainty
38- 43 F6.2 s Tp [37/277] Flare peak time tp in the rest frame
45- 49 F5.2 s e_Tp [2/17] Tp uncertainty
51- 57 E7.3 10-7W Lp [5.1e+48/1.2e+51] Flare peak luminosity Lp
59- 65 E7.3 10-7W e_Lp [1.3e+48/2.7e+50] Lp uncertainty
67- 72 F6.2 s Delt [10/164] Flare duration Δt (1)
74- 78 F5.2 s e_Delt [2/31] Delt uncertainty
80- 86 E7.3 10-7J Ef [3e+50/3.2e+52] Flare energy Ef within the
time interval
88- 94 E7.3 10-7J e_Ef [2.2e+49/5.7e+51] Ef uncertainty
96- 99 F4.2 --- alpf [1.2/3.7] Power-law index αf from the
fitting of the flare's spectrum
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Note (1): The flare duration where the starting and ending time correspond to
half of the peak luminosity.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- GRB GRB identifier
9- 14 F6.4 --- z [0.8/4.2] Redshift
16- 22 E7.3 10-7J Eiso [9.5e+51/2e+54] GRB isotropic energy (Eiso)
24- 30 E7.3 10-7J e_Eiso [1.7e+51/7.7e+53] Eiso uncertainty
32- 38 E7.3 10-7J Efpa [1.4e+50/7e+52] Flare-Plateau-Afterglow energy
(EFPA) from the flare until 109s
40- 46 E7.3 10-7J e_Efpa [1.4e+49/9.6e+51] Efpa uncertainty
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- GRB GRB identifier
9 A1 --- f_GRB [b] Flag on GRB (2)
11- 17 E7.3 cm Rad [1e+11/3.7e+12]? Radius (3)
19- 25 E7.3 cm e_Rad [1e+11/3e+12]? Rad 1σ uncertainty
27 A1 --- f_Rad [u] u: unconstrained
29- 32 F4.2 keV kTobs [0.2/1.8]? Observed temperature kTobs (4)
34- 37 F4.2 keV e_kTobs [0.03/1.3]? kTobs 1σ uncertainty
39 A1 --- f_kTobs [u] u: unconstrained
41- 45 F5.3 --- Sig [0/1] Significance (5)
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Note (2):
b = These GRBs have prominent blackbodies, with radii of the order of
∼1011-1012cm.
Note (3): The radii are calculated assuming mildly relativistic motion
(β=0.8) and isotropic radiation.
Note (4): The observed temperatures kTobs are inferred from fitting with
a power-law plus blackbody spectral model.
Note (5): The significance of a blackbody is computed by the maximum likelihood
ratio for comparing nested models and its addition improves a fit
when the significance is >0.95.
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- GRB GRB identifier (1)
9- 14 F6.4 --- z [0.1/9.3] Redshift
16- 21 F6.2 10+45J Eiso [0.7/438] Isotropic energy; 1e+52ergs
23- 29 F7.4 10+45J e_Eiso [0.02/86] Uncertainty in Eiso
31- 32 A2 --- LX Swift/XRT data flag (2)
34 A1 --- E/C Early flare flag (C=confirmed) (3)
36- 37 A2 --- UL Ultra-long flag (UL: a source with T90≥1000s)
39- 46 F8.2 s T90 [2/11900] Duration (4)
48- 57 A10 --- Inst Initial detection instrument (5)
59- 67 A9 --- Ref Reference (see refs.dat file)
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Note (1): GRB 090404A is very likely GRB 090404; same thing for
GRB 070802A, GRB 090201A, GRB 090205A, GRB 090313A, GRB 090726A,
GRB 090812A and GRB 091029A which have been updated for the same name
without the "A" component by CDS.
Note (2): "LX" sources have Swift/XRT data observed up to times larger than
1e+4s in the rest-frame after the initial explosion.
Note (3): Sources showed an early an early flare in the Swift/XRT data.
C = Confirmed. These 16 sources compose the sample in the paper.
E = excluded.
Note (4): When 90% of the total energy has been emitted.
Note (5): Instrument as follows:
B-SAX = Beppo-SAX/GRBM (40-700keV);
BATSE = Compton-GRO/BATSE (50-300keV);
Ulysses = Ulysses/GRB;
KW = Konus-WIND (50-200keV);
HETE = HETE-2/FREGATE;
Swift = Swift/BAT (15-150keV);
Fermi = Fermi/GBM (8keV-30MeV).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- Ref Reference code
3- 21 A19 --- BibCode Bibcode of the reference
23- 38 A16 --- Auth First author's name
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Sep-2018