Gamma-ray Burst 150211A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 11:52:27 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     630714,   Seg_Num: 0
GRB_RA:          254.856d {+16h 59m 25s} (J2000),
                 254.932d {+16h 59m 44s} (current),
                 254.605d {+16h 58m 25s} (1950)
GRB_DEC:         +55.383d {+55d 22' 59"} (J2000),
                 +55.361d {+55d 21' 40"} (current),
                 +55.456d {+55d 27' 23"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6807 [cnts]    Image_Peak=481 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   149     E_range: 25-100 keV
BKG_INTEN:       28867 [cnts]
BKG_TIME:        42714.82 SOD {11:51:54.82} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17064 TJD;    42 DOY;   15/02/11
GRB_TIME:        42731.53 SOD {11:52:11.53} UT
GRB_PHI:          13.30 [deg]
GRB_THETA:        49.55 [deg]
SOLN_STATUS:     0x403
RATE_SIGNIF:     50.52 [sigma]
IMAGE_SIGNIF:    18.82 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +6  +0  +0  +1  +0 
SUN_POSTN:       324.78d {+21h 39m 08s}  -14.04d {-14d 02' 07"}
SUN_DIST:         90.55 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.02d {+14h 52m 04s}  -13.41d {-13d 24' 41"}
MOON_DIST:        73.83 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.54, 37.78 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.82, 76.70 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 83.20,15.48 [deg].  
COMMENTS:           
COMMENTS:        This trigger occured while the StarTracker had lost lock, so it is possibly bogus.

red DSS finding chart ps-file

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 11 Feb 15 11:52:54 UT 
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    6882,   Sub_Num: 0
GRB_INTEN:      9.96 [sigma]   
GRB_TIME:       42728.18 SOD {11:52:08.18} UT
GRB_DATE:       17064 TJD;    42 DOY;   15/02/11
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=0.0500 and Time_Error=0.0250. 
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=630714).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2015-02/2015-02-11T11-52-08.0125-07483-48016-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 11:56:04 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     630714,   Seg_Num: 0
GRB_RA:          254.856d {+16h 59m 25s} (J2000),
                 254.932d {+16h 59m 44s} (current),
                 254.605d {+16h 58m 25s} (1950)
GRB_DEC:         +55.383d {+55d 22' 59"} (J2000),
                 +55.361d {+55d 21' 40"} (current),
                 +55.456d {+55d 27' 23"} (1950)
GRB_DATE:        17064 TJD;    42 DOY;   15/02/11
GRB_TIME:        42731.53 SOD {11:52:11.53} UT
TRIGGER_INDEX:   149
GRB_PHI:          13.30 [deg]
GRB_THETA:        49.55 [deg]
DELTA_TIME:      -69.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x403
RATE_SIGNIF:     50.52 [sigma]
IMAGE_SIGNIF:    18.82 [sigma]
LC_URL:          sw00630714000msb.lc
SUN_POSTN:       324.79d {+21h 39m 09s}  -14.03d {-14d 02' 04"}
SUN_DIST:         90.55 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.05d {+14h 52m 12s}  -13.42d {-13d 25' 06"}
MOON_DIST:        73.83 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.54, 37.78 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.82, 76.70 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 83.20,15.48 [deg].  
COMMENTS:           
COMMENTS:        This trigger occured while the StarTracker had lost lock, so it is possibly bogus.

GCN Circular #17433
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB150211A 39 sec after notice time and 55 sec after trigger time at 2015-02-11 11:53:08 UT in two polarizations. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (ra=16 59 25 dec=+55 22 58 r=0.050000). The 5-sigma upper limit has been about 15.5 mag The position hava a high (z~75d) zenith distance. The observation and data reductions is continued. The message may be cited.
GCN Circular #17434
R. L. C. Starling (U Leicester), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of the Swift Team:
At 11:52:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150211A (trigger=630714). Swift did not slew because of observing constraint. The BAT on-board calculated location is RA, Dec 254.856, +55.383, which is
```
   RA(J2000)  =  16h 59m 25s
   Dec(J2000) = +55d 22' 59"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks structure with a total duration of about 20 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~4 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+33.7 minutes. There will be no XRT or UVOT data until this time.
The star tracker lost lock about 1 minute before the trigger, but the location should be good by propagating the gyros. INTEGRAL-SPIACS also saw this burst.
Burst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:27:30 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     630714,   Seg_Num: 0
POINT_RA:        254.849d {+16h 59m 24s} (J2000)
POINT_DEC:       +55.395d {+55d 23' 43"} (J2000)
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44842.51 SOD {12:27:22.51} UT,   2111.0 [sec] since BAT Trigger Time
COUNTS:          3    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:30:18 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     630714,   Seg_Num: 0
POINT_RA:        254.850d {+16h 59m 24s} (J2000)
POINT_DEC:       +55.395d {+55d 23' 43"} (J2000)
POINT_ROLL:      114.261d
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44847.28 SOD {12:27:27.28} UT,   2115.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.415
N_STARS:         47
X_OFFSET:        552 [pixels]
Y_OFFSET:        567 [pixels]
X_MAX:           1511 [pixels]
Y_MAX:           1526 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00630714000msufc2115.fits
SUN_POSTN:       324.81d {+21h 39m 15s}  -14.03d {-14d 01' 36"}
SUN_DIST:         90.56 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.35d {+14h 53m 23s}  -13.48d {-13d 28' 58"}
MOON_DIST:        73.81 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.56, 37.78 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.78, 76.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:30:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     630714,   Seg_Num: 0
POINT_RA:        254.850d {+16h 59m 24s} (J2000)
POINT_DEC:       +55.395d {+55d 23' 43"} (J2000)
POINT_ROLL:      114.261d
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44847.28 SOD {12:27:27.28} UT,   2115.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.415
N_STARS:         47
X_OFFSET:        552 [pixels]
Y_OFFSET:        567 [pixels]
X_MAX:           1511 [pixels]
Y_MAX:           1526 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00630714000msufc2115.fits
SUN_POSTN:       324.81d {+21h 39m 15s}  -14.03d {-14d 01' 35"}
SUN_DIST:         90.56 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.35d {+14h 53m 24s}  -13.48d {-13d 29' 02"}
MOON_DIST:        73.81 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.56, 37.78 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.78, 76.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:31:51 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     630714,   Seg_Num: 0
POINT_RA:        254.850d {+16h 59m 24s} (J2000)
POINT_DEC:       +55.395d {+55d 23' 43"} (J2000)
ROLL:            114.261d
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44847.28 SOD {12:27:27.28} UT,   2115.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     445350460
X_OFFSET:        871 [pixels]
Y_OFFSET:        886 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1031
Y_GRB_POS:       1046
BINNING_INDEX:   1
IM_URL:          sw00630714000msuni2129.fits
SUN_POSTN:       324.81d {+21h 39m 15s}  -14.03d {-14d 01' 34"}
SUN_DIST:         90.56 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.36d {+14h 53m 26s}  -13.49d {-13d 29' 09"}
MOON_DIST:        73.81 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.56, 37.78 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.78, 76.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:32:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     630714,   Seg_Num: 0
POINT_RA:        254.850d {+16h 59m 24s} (J2000)
POINT_DEC:       +55.395d {+55d 23' 43"} (J2000)
ROLL:            114.261d
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44847.28 SOD {12:27:27.28} UT,   2115.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     445350460
X_OFFSET:        871 [pixels]
Y_OFFSET:        886 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1031
Y_GRB_POS:       1046
BINNING_INDEX:   1
IM_URL:          sw00630714000msuni2129.fits
SUN_POSTN:       324.81d {+21h 39m 15s}  -14.03d {-14d 01' 34"}
SUN_DIST:         90.56 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.36d {+14h 53m 27s}  -13.49d {-13d 29' 10"}
MOON_DIST:        73.81 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.56, 37.78 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      229.78, 76.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 11 Feb 15 12:31:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     630714,   Seg_Num: 0
GRB_RA:          254.8585d {+16h 59m 26.03s} (J2000),
                 254.9345d {+16h 59m 44.27s} (current),
                 254.6077d {+16h 58m 25.85s} (1950)
GRB_DEC:         +55.3924d {+55d 23' 32.6"} (J2000),
                 +55.3705d {+55d 22' 13.7"} (current),
                 +55.4657d {+55d 27' 56.5"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17064 TJD;    42 DOY;   15/02/11
IMG_START_TIME:  44852.00 SOD {12:27:32.00} UT,   2120.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       324.81d {+21h 39m 15s}  -14.03d {-14d 01' 34"}
SUN_DIST:         90.56 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      223.36d {+14h 53m 27s}  -13.49d {-13d 29' 10"}
MOON_DIST:        73.81 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       83.55, 37.78 [deg] galactic lon,lat of the burst
ECL_COORDS:      229.81, 76.71 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #17435
S. Campana (INAF-OAB), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 150211A at 12:27:22.5 UT, 2111.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 254.85863, 55.39235 which is equivalent to:
```
   RA(J2000)  = 16h 59m 26.07s
   Dec(J2000) = +55d 23' 32.5"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 34 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.61 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 5.1 (+2.58/-2.25) x 10^21 cm^-2 (90% confidence).
GCN Circular #17436
M. M. Chester (Penn State) and R. L. C. Starling (U. Leicester) report on behalf of the Swift/UVOT team:
UVOT took a finding chart exposure of 150 seconds with the White filter starting 2115 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02.
GCN Circular #17437
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=C3=A9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=C3=BAs Gonz=C3=A1lez (UNAM), Carlos Rom=C3=A1= n-Z=C3=BA=C3=B1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 150211A (Starling, et al., GCN 17434) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=C3=B3mico Nacional on Sierra San Pedro M=C3=A1rtir from 2015/02 11.50 to 2015/02 11.53 UTC (0.05 to 1.29 hours after the BAT trigger), obtaining a total of 1.07 hours exposure in the r, i and z bands.
For a source within the Swift-XRT error circle (Campana, et al., GCN 17435), in comparison with USNO-B1 and 2MASS, we obtain the following upper limits (3-sigma):
```
  r     > 23.34
  i     > 23.71
  z     > 20.21
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. These upper limits are consistent with observations by the Swift-UVOT (Chester, et al, GCN 17436) and MASTER II robotic telescope (Ivanov, et al, GCN 17433).
We thank the staff of the Observatorio Astron=C3=B3mico Nacional in San Pedro M=C3=A1rtir.
GCN Circular #17442
R. L. C. Starling (U Leicester) reports on behalf of the Swift-XRT team:
We have analysed 837 s of XRT data for GRB 150211A (Starling et al. GCN Circ. 17434), from 2.1 ks to 3.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 254.8581, +55.3927 which is equivalent to:
```
RA (J2000): 16 59 25.94
Dec(J2000): +55 23 33.5
```
with an uncertainty of 3.6 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.0 (+/-0.9).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.83 (+0.21, -0.20). The best-fitting absorption column is 6.2 (+1.6, -1.4) x 10^21 cm^-2, in excess of the Galactic value of 1.6 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (7.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.2 (+1.6, -1.4) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 7.1 sigma
Photon index:	     1.83 (+0.21, -0.20)
```
If the light curve continues to decay with a power-law decay index of 1.0, the count rate at T+24 hours will be 0.029 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-12 (2.1 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00630714.
This circular is an official product of the Swift-XRT team.
GCN Circular #17443
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150211A (Starling, et al., GCN 17434) with AZT-33IK telescope of Sayan observatory (Mondy). We obtained several images in R-filter on Feb., 11, starting (UT) 12:02:35. Within XRT error cirvle (Campana, et al.,GCN 17435) we do not detect any optical source. Upper limit is following
```
Date       UT start   t-T0     Filter   Exp.  UL(3sigma)
                       (mid, days)       (s)

2015-02-11 12:02:35   0.03091  R       1800   21.9
```
The photometry is based on nearby USNO-B1.0 stars:
```
USNO-B1.0_id     R2
1453-0255559    18.45
1453-0255560    18.27
1453-0255536    18.49
```
GCN Circular #17444
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 150211A (Starling al., GCN 17434) starting at 11:54:12 UT, 121 s after the burst. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. We do not detect any new source in our images within the refined XRT error circle (Starling et al., GCN 17442). The typical limiting magnitude of our single clear image is about 18.0 calibrated to USNO B1.0.
GCN Circular #17445
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), R. L. C. Starling (U Leicester), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150211A (trigger #630714) (Starling, et al., GCN Circ. 17434). The BAT ground-calculated position is RA, Dec = 254.846, 55.390 deg, which is
```
   RA(J2000)  =  16h 59m 23.0s 
   Dec(J2000) = +55d 23' 23.2" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%.
The mask-weighted light curve shows several overlapping peaks starting at ~T-10 sec, peaking at ~T+5 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 13.6 +- 2.0 sec (estimated error including systematics).
The time-averaged spectrum from T-11.24 to T+9.18 sec is best fit by a Double Blackbody. This fit gives a kT1 = 7.99 +2.8/-2.1 keV, kT2 = 24.7 +7.5/-3.2 keV, and (R1/D10)^2 = 6.0 +9.1/-3.3 and R2/D10)^2 = 0.22 +0.11/-0.15. (chi squared 74.8 for 59 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.9 +- 1.2 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+4.36 sec in the 15-150 keV band is 12 +- 1 ph/cm2/sec. A Cutoff PL has an Epeak of 123.4 +- 27.5 keV (chi squared 81.8 for 56 d.o.f.). And for completeness, the fit to a simple power law gives a photon index of 1.28 +- 0.05 (chi squared 107 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/630714/BA/
GCN Circular #17447
M. M. Chester (Penn State) 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 150211A 2116 s after the BAT trigger (Starling et al., GCN Circ. 17434). No optical afterglow consistent with the XRT position (Starling GCN Circ. 17442) 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 first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC          2116         2266          147         >21.3
white             2116         3123          383         >21.8
v                 2272         8220          255         >20.4
b                 2371         2918          236         >20.1
u                 2346         2713           58         >19.7
w1                2321         2688           58         >19.4
m2                8225         8421          193         >20.4
w2                3129         3243          112         >19.9
```
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 #17448
D. Kawamura, T. Sakamoto, A. Yoshida (AGU)
We observed the field of GRB 150211A detected by Swift (trigger #630714; Starling et al., GCN Circ. 17434) with the iTelescope.Net (http://www.itelescope.net) T11 (0.50 m Plane Wave) telescope located at the New Mexico Skies Observatory (NM, USA). 20 images of 60 sec exposures were taken in the R filter starting from February 11 12:06:11 (UT) about 14.3 minutes after the trigger and stopped on February 11 12:32:17 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the enhanced X-ray afterglow position (Starling et al., GCN Circ. 17442). The estimated five sigma upper limit of the combined image (total exposure of 1200 sec) is ~19.1 using the USNO-B1 catalog.
GCN Circular #17450
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 150211A (Swift-BAT trigger #630714: Starling et al., GCN 17434) triggered Konus-Wind at T0=42728.740 s UT (11:52:08.740).
The KW light curve shows a single multi-peaked emission episode with a duration of ~13 s. The emission is visible up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150211_T42728/
As observed by Konus-Wind, the burst had a fluence of 2.4(-0.3,+0.3)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+7.808 s, of 5.6(-0.7,+0.7)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+16.128 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.62 (-0.20,+0.25), the high energy photon index beta = -2.07 (-0.15,+0.10), the peak energy Ep = 145 (-24,+30) keV, chi2 = 114/97 dof.
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #17461
F. V. Ferrante (SMU), T. Guver (Istanbul U), G. Dhungana (SMU), R. Staten (SMU)
and R. Kehoe (SMU) report on behalf of the ROTSE GRB team:
The 0.45-m ROTSE-IIIb telescope, located at McDonald Observatory, Texas,
responded to GRB 150211A (Swift trigger 630714; Starling, et al.,GCN 17434) with
imaging beginning 3.8 s after the GCN notice time. An automated response recorded
the first image at 11:52:43.8 UT, 30.7 s after the burst, under fair observing conditions.
The unfiltered images are calibrated relative to USNO A2.0 (R). We do not detect an
optical source within the refined Swift-XRT error circle (Starling et al., GCN 17442).
We set the following upper limit:
```
start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
-----------------------------------------------------------------------------------------------
11:52:43.8   11:53:43.8      60       17.6           30.7               N
```

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Jochen Greiner, last update: 12-Feb-2015 [Disclaimer]