Gamma-ray Burst 090814B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 14 Aug 09 01:21:42 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    5905,   Sub_Num: 0
GRB_RA:          64.7323d {+04h 18m 56s} (J2000),
                 64.9416d {+04h 19m 46s} (current),
                 63.6481d {+04h 14m 36s} (1950)
GRB_DEC:        +60.6013d {+60d 36' 05"} (J2000),
                +60.6241d {+60d 37' 27"} (current),
                +60.4801d {+60d 28' 48"} (1950)
GRB_ERROR:      3.27 [arcmin, radius, statistical only]
GRB_INTEN:      8.24 [sigma]
GRB_TIME:       4885.01 SOD {01:21:25.01} UT
GRB_DATE:       15057 TJD;   226 DOY;   09/08/14
SC_RA:           72.78 [deg] (J2000)
SC_DEC:          50.52 [deg] (J2000)
SUN_POSTN:      143.78d {+09h 35m 08s}  +14.37d {+14d 22' 01"}
SUN_DIST:        72.05 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:      51.11d {+03h 24m 27s}  +23.55d {+23d 33' 07"}
MOON_DIST:       38.29 [deg]
GAL_COORDS:     145.84,  7.33 [deg] galactic lon,lat of the burst
ECL_COORDS:      74.47, 38.52 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Possibly real GRB event

red DSS finding chart ps-file

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 14 Aug 09 01:24:42 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    5905,   Sub_Num: 1
GRB_RA:          64.7447d {+04h 18m 59s} (J2000),
                 64.9540d {+04h 19m 49s} (current),
                 63.6603d {+04h 14m 38s} (1950)
GRB_DEC:        +60.6079d {+60d 36' 29"} (J2000),
                +60.6307d {+60d 37' 51"} (current),
                +60.4868d {+60d 29' 12"} (1950)
GRB_ERROR:      3.10 [arcmin, radius, statistical only]
GRB_INTEN:      9.45 [sigma]
GRB_TIME:       4893.09 SOD {01:21:33.09} UT
GRB_DATE:       15057 TJD;   226 DOY;   09/08/14
SC_RA:           72.78 [deg] (J2000)
SC_DEC:          50.52 [deg] (J2000)
SUN_POSTN:      143.79d {+09h 35m 09s}  +14.37d {+14d 21' 58"}
SUN_DIST:        72.05 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:      51.14d {+03h 24m 34s}  +23.56d {+23d 33' 28"}
MOON_DIST:       38.29 [deg]
GAL_COORDS:     145.84,  7.34 [deg] galactic lon,lat of the burst
ECL_COORDS:      74.48, 38.52 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 14 Aug 09 02:55:58 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    5905,   Sub_Num: 2
GRB_RA:          64.7488d {+04h 19m 00s} (J2000),
                 64.9580d {+04h 19m 50s} (current),
                 63.6649d {+04h 14m 40s} (1950)
GRB_DEC:        +60.5794d {+60d 34' 46"} (J2000),
                +60.6022d {+60d 36' 08"} (current),
                +60.4583d {+60d 27' 30"} (1950)
GRB_ERROR:      2.88 [arcmin, radius, statistical only]
GRB_INTEN:      9.45 [sigma]
GRB_TIME:       4893.09 SOD {01:21:33.09} UT
GRB_DATE:       15057 TJD;   226 DOY;   09/08/14
SC_RA:           72.78 [deg] (J2000)
SC_DEC:          50.52 [deg] (J2000)
SUN_POSTN:      143.85d {+09h 35m 23s}  +14.35d {+14d 20' 48"}
SUN_DIST:        72.09 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:      52.07d {+03h 28m 16s}  +23.74d {+23d 44' 11"}
MOON_DIST:       37.93 [deg]
GAL_COORDS:     145.87,  7.32 [deg] galactic lon,lat of the burst
ECL_COORDS:      74.47, 38.49 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       refined_coordinates_after_offline_analysis

GCN Circular #9795
V.Beckmann (ISDC, Versoix), D.Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), A. Neronov, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
A long GRB with duration of about 50 s has been detected by IBAS in IBIS/ISGRI data at 01:21:33 UT on August 14th.
The refined coordinates (J2000) are:
```
  RA:   64.7488 [degrees]
  DEC: +60.5796 [degrees]
```
with an uncertainty of 2.9 arcmin (90% c.l.).
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.
GCN Circular #9803
P.A. Evans (U. Leicester) and W.H. Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team:
The Swift-XRT observed the field of the INTEGRAL GRB 090814B (Beckmann et al. GCN. Circ. 9795), gathering 900-s of data in the interval T0+9 ks to T0+14 ks.
In the INTEGRAL error circle we find a single, uncatalogued X-ray source at RA,Dec=64.7546, 60.5901 which is equivalent to:
```
RA (J2000): 04h 19m 01.10s
Dec (J2000): +60d 35' 24.34"
```
with an uncertainty of 3.8 arcsec (radius, 90% confidence).
The source has a count-rate of ~0.03 count/sec, but we are unable to determine at the present time whether the source is fading.
The spectrum comprises only 24 photons, but it can be well modelled with an absorbed power-law with photon index Gamma=0.8 (+/-1.3) and a column density of 9.0 (+16.0, -5.4) x 10^21 cm^-2, in excess of the Galactic value if 3.6 x 10^21 cm^-2 (Kalberla et al. 2005).
Swift will conduct a further 4-ks observation of this source today.
This circular is an official product of the Swift-XRT team.
GCN Circular #9806
C. Guidorzi (U. Ferrara), Z. Cano (Liverpool JMU), A. Gomboc (U. Ljubljana), C.G. Mundell, I.A. Steele, A. Melandri, S. Kobayashi, C.J. Mottram, D.F. Bersier, R.J. Smith (Liverpool JMU) report on behalf of a large collaboration:
On 2009 August 14 at 02:57:31 UT the 2-m Liverpool Telescope automatically began observing the INTEGRAL GRB 090814B (Beckmann et al., GCN Circ. 9795) using the g',r' and i' filters.
We do not detect any uncatalogued source inside the Swift-XRT error circle (Evans et al. GCN Circ 9803) down to the following values:
```
Mid Time   Delay from GRB   Total Exp  Filter   Upper limit
(UT)       (hours)          (s)                 Magnitude
-----------------------------------------------------------
03:26:17    2.08            600         R         > 21.3
03:27:52    2.11            540         I         > 21.0
---------------------------------------------------------
```
Magnitudes have been calibrated from the nearby USNOB-1 star 04:19:01.476, +60:35:18.11 using R2=18.34 and I=17.14.
We note the considerable Galactic reddening along the GRB direction: E(B-V)=1.14 (Schlegel et al. 1998).
GCN Circular #9807
P.A. Curran (MSSL-UCL) and W.H. Baumgartner (GSFC/UMBC) report on behalf of the Swift/UVOT team:
Swift/UVOT observed the field of the INTEGRAL GRB 090814B (Beckmann et al. GCN. Circ. 9795), gathering 950s of data in the from interval T0+9ks to T0+14 ks.
No optical afterglow consistent with the Swift XRT position (Evans et al., GCN 9803) is detected in the UVOT exposures. Preliminary 3-sigma upper limits, using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627), are:
```
Filter   T_start(s)   T_stop(s)   Exp(s)   Mag
u        8044	      14166       506      >20.32
w2       8485	      8933        441      >20.30
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 1.10 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #9808
J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (INAF-OAB), V. Terron (IAA-CSIC), M. Fernandez (IAA-CSIC), S. Guziy (IAA-CSIC), S. Castillo (Univ. Malaga), M. Jelinek (IAA-CSIC), P. Kubanek (IAA-CSIC & IPL Univ. Valencia), A.J. Castro-Tirado (IAA-CSIC), report;
We carried out I-band observations of the INTEGRAL GRB 090814B (Beckmann et al. GCN 9795) with the 1.23m Calar Alto telescope as follows;
```
---------------------------------------------------------
    Date         Time since GRB    Exp.     Lim.
 Start - End      Start - End      Time     Mag.
    (UT)              (Sec)        (Sec)   (3 sigma)
---------------------------------------------------------
14.0606 - 14.0739   342 - 1492     5 x 180  19.8
14.0745 - 14.0865  1544 - 2583     3 x 300  19.8
14.0871 - 14.0963  2635 - 3430     2 x 360  20.0
14.0973 - 14.1912  3518 - 11631   10 x 700  20.3
---------------------------------------------------------
```
No optical object is detected in the XRT position determined by Swift (Evans et al. GCN 9803) for the upper limits given above. The combination of all the images sets an upper limit of I = 20.6 with a total exposure time of 9520s and a mean observing epoch of Aug 14.1259 UT.
GCN Circular #9810
P.A. Evans (U. Leicester) and W.H. Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team:
The Swift-XRT conducted a second observation of GRB 090814B (Beckmann et al. GCN. Circ. 9795), gathering 3.3 ks of data between T0+48 ks and T0+60 ks. The source reported by Evans & Baumgartner (GCN Circ. 9803) has faded to a level of 0.11 =C2=B1 0.03 count/sec, with a power-law decay index of alpha=3D0.7+/-0.3. This source is thus confirmed as the afterglow of GRB 090814B.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020107.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 15-Aug-2009 [Disclaimer]