Gamma-ray Burst 140320B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN NOTICE

TITLE:GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 20 Mar 14 09:26:28 UT
NOTICE_TYPE:    INTEGRAL Weak 
TRIGGER_NUM:    6553,   Sub_Num: 0
GRB_RA:         145.5662d {+09h42m 16s} (J2000),
                145.8262d {+09h43m 18s} (current),
                144.6458d {+09h38m 35s} (1950)
GRB_DEC:        +60.2416d {+60d14' 30"} (J2000),
                +60.1762d {+60d 10' 34"} (current),
                +60.4699d {+60d 28' 12"} (1950)
GRB_ERROR:      3.57 [arcmin, radius, statistical only]
GRB_INTEN:      6.78 [sigma]
GRB_TIME:       33980.26 SOD {09:26:20.26} UT
GRB_DATE:       16736 TJD;    79 DOY;   14/03/20
SC_RA:          136.79 [deg] (J2000) 
SC_DEC:          67.10 [deg] (J2000) 
SUN_POSTN:      359.72d {+23h 58m 52s}   -0.12d{-00d 07' 18"}
SUN_DIST:       114.50 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:     221.10d {+14h 44m 23s}  -14.54d {-14d 32' 24"}
MOON_DIST:      95.47 [deg]
GAL_COORDS:     153.43, 44.06 [deg] galactic lon,lat ofthe burst
ECL_COORDS:     124.18, 43.22 [deg] ecliptic lon,lat ofthe burst
COMMENTS:       INTEGRAL GRB Coordinates -- this is theweak/subthreshold trigger notice.
COMMENTS:       This notice may or may not be followed by a Wakeup/Refined/Offline notice.
COMMENTS:       Time_Scale=40.0000 and Time_Error=40.0000.
COMMENTS:       Possibly real GRB event (WEAK detection)

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 20 Mar 14 09:26:57 UT 
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    6553,   Sub_Num: 1
GRB_RA:         145.5575d {+09h 42m 14s} (J2000),
                145.8176d {+09h 43m 16s} (current),
                144.6369d {+09h 38m 33s} (1950)
GRB_DEC:        +60.2602d {+60d 15' 37"} (J2000),
                +60.1948d {+60d 11' 41"} (current),
                +60.4885d {+60d 29' 19"} (1950)
GRB_ERROR:      3.30 [arcmin, radius, statistical only]
GRB_INTEN:      8.03 [sigma]   
GRB_TIME:       34008.26 SOD {09:26:48.26} UT
GRB_DATE:       16736 TJD;    79 DOY;   14/03/20
SC_RA:          136.79 [deg] (J2000)
SC_DEC:          67.10 [deg] (J2000)  
SUN_POSTN:      359.72d {+23h 58m 53s}   -0.12d{-00d 07' 18"}
SUN_DIST:       114.48 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:     221.10d{+14h 44m 24s}-14.54d{-14d 32' 27"}
MOON_DIST:      95.49 [deg]
GAL_COORDS:     153.41, 44.05 [deg] galactic lon,lat ofthe burst
ECL_COORDS:     124.16, 43.24 [deg] ecliptic lon,lat ofthe burst
COMMENTS:       INTEGRAL GRB Coordinates.
COMMENTS:       Time_Scale=20.0000 and Time_Error=20.0000.
COMMENTS:       Possibly real GRB event

GCN NOTICE

 
 TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 20 Mar 14 09:29:53 UT 
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    6553,   Sub_Num: 2
GRB_RA:         145.5655d {+09h 42m 16s} (J2000),
                145.8256d {+09h 43m 18s} (current),
                144.6450d {+09h 38m 35s} (1950)
GRB_DEC:        +60.2550d {+60d 15' 18"} (J2000),
                +60.1896d {+60d 11' 23"} (current),
                +60.4833d {+60d 28' 60"} (1950)
GRB_ERROR:      3.20 [arcmin, radius, statistical only]
GRB_INTEN:      8.70 [sigma]
GRB_TIME:       34020.26 SOD {09:27:00.26} UT
GRB_DATE:       16736 TJD;    79 DOY;   14/03/20
SC_RA:          136.79 [deg] (J2000)
SC_DEC:          67.10 [deg] (J2000)  
SUN_POSTN:      359.72d {+23h 58m 53s}   -0.12d{-00d 07' 15"}
SUN_DIST:       114.49 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:     221.13d{+14h 44m 31s}-14.55d{-14d 32' 48"}
MOON_DIST:      95.50 [deg]
GAL_COORDS:     153.42, 44.06 [deg] galactic lon,lat ofthe burst
ECL_COORDS:     124.17, 43.24 [deg] ecliptic lon,lat ofthe burst
COMMENTS:       INTEGRAL GRB Coordinates.
COMMENTS:       Time_Scale=40.0000 and Time_Error=40.0000.
COMMENTS:       Possibly real GRB event

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 20 Mar 14 10:06:43 UT 
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    6553,   Sub_Num: 3
GRB_RA:         145.5408d {+09h 42m 10s} (J2000),
                145.8010d {+09h 43m 12s} (current),
                144.6198d {+09h 38m 29s} (1950)
GRB_DEC:        +60.2794d {+60d 16' 46"} (J2000),
                +60.2140d {+60d 12' 50"} (current),
                +60.5076d {+60d 30' 28"} (1950)
GRB_ERROR:      2.00 [arcmin, radius, statistical only]
GRB_INTEN:      8.70 [sigma]   
GRB_TIME:       34020.26 SOD {09:27:00.26} UT
GRB_DATE:       16736 TJD;    79 DOY;   14/03/20
SC_RA:          136.79 [deg] (J2000)
SC_DEC:          67.10 [deg] (J2000)  
SUN_POSTN:      359.74d {+23h 58m 59s}   -0.11d{-00d 06' 38"}
SUN_DIST:       114.44 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:221.47d{+14h 45m 52s}-14.62d{-14d 37' 05"}
MOON_DIST: 95.74 [deg]
GAL_COORDS:     153.39, 44.04 [deg] galactic lon,lat ofthe burst
ECL_COORDS:     124.14, 43.25 [deg] ecliptic lon,lat ofthe burst
COMMENTS:       INTEGRAL GRB Coordinates.
COMMENTS:       Time_Scale=40.0000 and Time_Error=40.0000.
COMMENTS:       refined_coordinates_after_offline_analysis

GCN Circular #16003
C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB), D. Kopac, A. Gomboc (U. Ljubljana), C.G. Mundell, F. Virgili (LJMU) on behalf of a larger collaboration report:
The 2-m Faulkes Telescope North automatically began observing INTEGRAL GRB 140320B on March 20 at 09:31:27 UT (~4.6 min after the burst trigger).
We find a fading uncatalogued object at coordinates
```
RA(2000.0)=   09:42:14.17
Dec(2000.0)=  +60:16:05.7  (error 1.0")
```
with i=19.7 +- 0.1 mag at 16 minutes after the GRB, calibrated against nearby SDSS-I stars.
GCN Circular #16004
S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, E.Filippova (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
a gamma ray burst lasting about 100 s has been detected by IBAS in the IBIS/ISGRI data at 09:26:00 UT of March 20.
The refined coordinates (J2000) are:
```
R.A.=  145.5409 deg
DEC.=  +60.2794 deg
```
with an uncertainty of 2 arcmin (90% c.l.).
A preliminary analysis gives a peak flux of 0.2 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 5e-7 erg/cmq.
A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular #16005
L. Elenin (KIAM), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko=20 (IKI) report on behalf of larger GRB follow-up collaboration:
We observed of the field of the INTEGRAL GRB 140320B (Mereghetti et=20 al., GCN 16004) with 0.4-m telescope of ISON-NM observatory starting=20 on Mar., 20 (UT) 09:35:41. We took unfiltered images of 30 s=20 exposures. We detect a fading optical afterglow of GRB 140320B=20 (Guidorzi et al., GCN 16003) in a stacked image of total exposure 300=20 s and do not detect it in the next stacked image of the same exposure.=20 Coordinates of the optical afterglow (J2000) 09 42 13.96 +60 16 05.9=20 (uncertainties of 1 arcsec) coincide with OT coordinates (Guidorzi et=20 al., GCN 16003). Preliminary photometry of first stacked images is=20 based on nearby USNO-B1.0 stars:
```
UT mid,      T0+      Filter  Exposure,  OT,    err OT
                  mid          s
09:38:39      0.00878 none    10=D1=8530     19.1    0.2
09:44:40      0.03102 none    10=D1=8530   > 19.3    UpperlLimit
```
GCN Circular #16006
L. P. Xin, J. Y. Wei, T. M. Zhang, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han and C. Wu on behalf of EAFON report:
We began to observe GRB 140320B (Mereghetti et al., GCN 16004) with Xinglong 0.8-m TNT telescope at 12:15:47(UT) , 2.83 hrs after the burst.
We do not detect the reported afterglow counterpart (Guidorzi et al., GCN 16003,Elenin et al., GCN 16005). in our combined images down to the upper limit of 21.8 mag in R band, calibrated by nearby USNO B1.0 R2 mag, at the mean time of 3.22 hrs after the burst.
GCN Circular #16013
C. Pagani, K.L. Page, R.L.C. Starling, (U. Leicester) report on behalf of the Swift-XRT team:
We have analysed 4 ks of XRT data for the INTEGRAL detected GRB 140320B (Mereghetti et al. GCN Circ. 16004), from 11.6 s to 23.1 ks after the trigger. The data are entirely in Photon Counting (PC) mode. An uncatalogued, fading X-ray source is detected inside the INTEGRAL error circle.
Using 3683 s of XRT PC data and 4 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 145.55932, 60.26822 which is equivalent to:
```
RA (J2000):  09 42 14.24
Dec (J2000): +60 16 05.6
```
with an uncertainty of 1.7 arcsec (radius, 90% confidence). This is consistent with the optical position reported by Guidorzi et al. (GCN 16003) and Elenin et al. (GCN 16005).
The light curve can be modelled with a power-law decay with an index of alpha=1.12 (+1.21, -0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.4, -0.3). The best-fitting absorption column is 6 (+8, -6) x 10^20 cm^-2, consistent with the Galactic value of 2.4 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.8 x 10^-11 (3.0 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 1.12, the count rate at T+24 hours will be 7.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x 10^-14 (2.3 x 10^-14) erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular #16019
S. R. Oates (UCL-MSSL) and R. L. C. Starling, (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140320B 11975 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 16004). No optical afterglow consistent with the XRT position (Pagani et al., GCN Circ. 16013) and the FTN optical position (Guidorzi et al., GCN Circ. 16003) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white            11975        29408         5864         >23.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #16024
D. A. Perley (Caltech) and S. B. Cenko (NASA-GSFC) report:
The Palomar 60-inch telescope automatically responded to the INTEGRAL trigger for GRB 130420B (Mereghetti et al. GCN 16004) and began taking a series of 60-second exposures in the r, i, and z filters starting at 2014-03-20 09:31:41.744 (7.12 minutes after the trigger).
The afterglow candidate reported by Guidorzi et al. (GCN 16003) is well-detected in the initial z-band exposure, weakly detected in the initial i-band exposure, and not detected in the initial r-band exposure. However, a weak r-band detection is recovered by stacking several images.
The light curve (in the i- and z-band filters) shows a rise to a peak at around 15 minutes post-trigger, followed by a decline up until the end of our sequence at 1.3 hours after the GRB.
Stacking the first 7 exposures in each filter, we estimate magnitudes of:
```
r = 21.29 +/- 0.24
i = 20.07 +/- 0.09
z = 17.97 +/- 0.03
```
At a mid-UT time of approximately 09:46 in each filter (20 minutes after the trigger).
The redder apparent color in i-z compared to r-i may suggest a highly reddened afterglow with host contribution to the r-band, or a reddened afterglow with a very strong 2175 dust feature at z~2.5, or a Lyman break in the i-band with some Lyman-alpha forest blueward (z~5). We encourage further observations, particularly in the NIR.

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Jochen Greiner, last update: 21-Mar-2014 [Disclaimer]