J/ApJ/774/114 GRB 081007 and GRB 090424 light curves (Jin+, 2013)
GRB 081007 and GRB 090424: the surrounding medium, outflows, and supernovae.
Jin Z.-P., Covino S., Della Valle M., Ferrero P., Fugazza D., Malesani D.,
Melandri A., Pian E., Salvaterra R., Bersier D., Campana S., Cano Z.,
Castro-Tirado A.J., D'Avanzo P., Fynbo J.P.U., Gomboc A., Gorosabel J.,
Guidorzi C., Haislip J.B., Hjorth J., Kobayashi S., LaCluyze A.P.,
Marconi G., Mazzali P.A., Mundell C.G., Piranomonte S., Reichart D.E.,
Sanchez-Ramirez R., Smith R.J., Steele I.A., Tagliaferri G., Tanvir N.R.,
Valenti S., Vergani S.D., Vestrand T., Walker E.S., Wozniak P.
<Astrophys. J., 774, 114 (2013)>
=2013ApJ...774..114J 2013ApJ...774..114J
ADC_Keywords: Gamma rays ; Photometry, UBVRI ; Supernovae
Keywords: gamma-ray: burst: individual (GRB 081007, GRB 090424);
ISM: jets and outflows; supernovae: individual: SN 2008hw
Abstract:
We discuss the results of the analysis of multi-wavelength data for
the afterglows of GRB 081007 and GRB 090424, two bursts detected by
Swift. One of them, GRB 081007, also shows a spectroscopically
confirmed supernova, SN 2008hw, which resembles SN 1998bw in its
absorption features, while the maximum magnitude may be fainter, up to
0.7mag, than observed in SN 1998bw. Bright optical flashes have been
detected in both events, which allows us to derive solid constraints
on the circumburst-matter density profile. This is particularly
interesting in the case of GRB 081007, whose afterglow is found to be
propagating into a constant-density medium, yielding yet another
example of a gamma-ray burst (GRB) clearly associated with a
massive-star progenitor which did not sculpt the surroundings with its
stellar wind. There is no supernova component detected in the
afterglow of GRB 090424, likely due to the brightness of the host
galaxy, comparable to the Milky Way. We show that the afterglow data
are consistent with the presence of both forward- and reverse-shock
emission powered by relativistic outflows expanding into the
interstellar medium. The absence of optical peaks due to the forward
shock strongly suggests that the reverse-shock regions should be
mildly magnetized. The initial Lorentz factor of outflow of GRB 081007
is estimated to be Γ∼200, while for GRB 090424 a lower limit of
Γ>170 is derived. We also discuss the prompt emission of
GRB 081007, which consists of just a single pulse. We argue that
neither the external forward-shock model nor the shock-breakout model
can account for the prompt emission data and suggest that the
single-pulse-like prompt emission may be due to magnetic energy
dissipation of a Poynting-flux-dominated outflow or to a dissipative
photosphere.
Description:
Many robotic telescopes reacted to the trigger from GRB 081007. RAPTOR
started observations detecting the optical counterpart after about 24s
in the R band (Wren et al. 2008GCN..8337....1W 2008GCN..8337....1W). Four of the 40cm
PROMPT telescopes at CTIO in Chile began observing after 41s (West et
al. 2008GCN..8352....1W 2008GCN..8352....1W). The 60cm Rapid Eye Mount (REM) on La Silla,
Chile, started multi-band observations of GRB 081007 after 46s in the
R, H, and Ks bands (Covino et al. 2008GCN..8331....1C 2008GCN..8331....1C). The 2m Faulkes
Telescope North (FTN; Haleakala, Hawaii) started to observe GRB 081007
about 17 minutes after the Swift trigger in the B, V, R, and I bands
(Smith et al. 2008GCN..8333....1S 2008GCN..8333....1S). The 2m Faulkes Telescope South
(Siding Spring, Australia) observed the field of GRB 081007 from ∼1.1
to ∼4.2 days after the burst in the R and I bands. Between 2008
October 24 and 2009 January 3, FORS2 at the Very Large Telescope (VLT)
was used to search for the SN associated with GRB 081007.
The 2m Liverpool Telescope (La Palma, Canary Islands, Spain) began
observing the field of GRB 090424 at 21:29:47 UT (Guidorzi et al.
2009GCN..9238....1G 2009GCN..9238....1G), ∼7hr after the burst. The optical counterpart
was clearly detected in the r and i filters. Later observations were
made by the FTN at 17.66 and 333.89 days after the trigger in the R
filter only. Between 2009 May 1 and July 5, FORS2 at the VLT was also
used to observe the GRB 090424 field for nine runs. Three years later,
this field was observed again between 2012 May 1 to 3 with the 3.5m
telescope at the Calar Alto Observatory.
Our dataset also includes Swift/UVOT data and we have retrieved and
analyzed public Gemini archival data of GRB 081007 and GRB 090424,
confirming results reported by Berger et al. (2008GCN..8335....1B 2008GCN..8335....1B) and
Chornock et al. (2009GCN..9243....1C 2009GCN..9243....1C).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 110 2 Properties of GRB 081007 and GRB 090424
table2.dat 42 192 Optical observations of GRB 081007
table3.dat 42 136 Optical observations of GRB 090424
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See also:
J/A+A/565/A72 : Opt. & X-ray light curves of BAT6 sample (Melandri+, 2014)
J/A+A/557/A12 : Optical light curves of γ-ray bursts (Zaninoni+, 2013)
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/763/15 : Fermi GRB analysis. III. T90 distributions (Qin+, 2013)
J/PASP/124/297 : GRB spectral lags (Li+, 2012)
J/ApJ/756/112 : Fermi/GBM GRB time-resolved spectral analysis (Lu+, 2012)
J/ApJ/746/170 : Follow-up resources for high-redshift GRBs (Morgan+, 2012)
J/A+A/538/A120 : A unified supernova catalogue (Lennarz+, 2012)
J/ApJS/195/2 : The second Swift BAT GRB catalog (BAT2) (Sakamoto+, 2011)
J/ApJ/720/1513 : The afterglows of Swift-era GRBs. I. (Kann+, 2010)
J/ApJ/711/495 : Durations of Swift/BAT GRBs (Butler+, 2010)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [GRB]
4- 9 I06 --- GRB GRB identifier (YYMMDD)
11- 12 I2 s T90 T90 duration
14 I1 s e_T90 ? T90 uncertainty
16 I1 --- r_T90 T90 reference (1)
18- 23 F6.4 --- z [0.52/0.55] Redshift
25- 30 F6.4 --- e_z ? z uncertainty
32- 34 I3 keV Epk Energy peak
36- 38 I3 keV E_Epk Positive error on Epk
40- 41 I2 keV e_Epk Negative error on Epk
43 I1 --- r_Epk Epk reference (1)
45- 51 E7.2 10-7J Eiso Isotropic-equivalent energy of the prompt
gamma-ray emission (Eγ,iso) in erg
53- 59 E7.2 10-7J E_Eiso Positive error on Eiso
61- 67 E7.2 10-7J e_Eiso Negative error on Eiso
69 I1 --- r_Eiso Eiso reference (1)
71 A1 --- l_gamma [~>] Limit flag on gamma
72- 74 I3 --- gamma [170/200] Outflow Lorentz factor (Γ,
see equation 3)
76 A1 --- l_RB [~>] Limit flag on RB
77- 89 A13 --- RB Fraction of the reverse (forward) shock energy
given to the magnetic field (see section 3.4)
91- 92 A2 --- --- [SN]
93- 98 A6 --- SN SN detection
100 A1 --- l_Rgal Limit flag on Rgal
101-105 F5.2 mag Rgal [22/25] R-band host galaxy magnitude
107-110 F4.2 mag e_Rgal ? Rgal uncertainty
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Note (1): Reference as follows:
1 = de Ugarte Postigo et al. 2011A&A...525A.109D 2011A&A...525A.109D;
2 = Sakamoto et al. 2009GCN..9231....1S 2009GCN..9231....1S;
3 = Sakamoto et al. 2011, J/ApJS/195/2
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Byte-by-byte Description of file: table[23].dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Inst Instrument used in the observation
8- 12 A5 --- Filt Filter used in the observation (UVW1, UVM2,
UVW2, White, ubv, BVRcIc, g'i'r'z', JHKs)
14- 23 F10.2 min Tmid Time of mid-exposure (1)
25- 30 F6.2 min Exp [0.01/212] Exposure time
32 A1 --- l_mag Limit flag on mag
33- 37 F5.2 mag mag [13.8/25] Observed AB magnitude in Filt (2)
39- 42 F4.2 mag e_mag [0.02/1.4]? Error in mag
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Note (1): Since trigger time: 2008 October 7 at 05:23:52 UT for GRB 081007 or
Since trigger time: 2009 April 24 at 14:12:09 UT for GRB 090424.
Note (2): Galactic extinction has not been removed.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Mar-2015