Gamma-ray Burst 150212A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Feb 15 10:57:34 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     630876,   Seg_Num: 0
GRB_RA:          285.521d {+19h 02m 05s} (J2000),
                 285.627d {+19h 02m 30s} (current),
                 285.172d {+19h 00m 41s} (1950)
GRB_DEC:         +47.407d {+47d 24' 27"} (J2000),
                 +47.430d {+47d 25' 48"} (current),
                 +47.334d {+47d 20' 01"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2381 [cnts]    Image_Peak=136 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   124     E_range: 25-100 keV
BKG_INTEN:       25183 [cnts]
BKG_TIME:        39426.82 SOD {10:57:06.82} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17065 TJD;    43 DOY;   15/02/12
GRB_TIME:        39439.04 SOD {10:57:19.04} UT
GRB_PHI:         -94.39 [deg]
GRB_THETA:        20.52 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     18.54 [sigma]
IMAGE_SIGNIF:    7.90 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  -2  +0  +0 -32  +0 
SUN_POSTN:       325.73d {+21h 42m 56s}  -13.72d {-13d 43' 02"}
SUN_DIST:         70.85 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.38d {+15h 41m 30s}  -15.76d {-15d 45' 41"}
MOON_DIST:        77.51 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      300.66, 69.20 [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 = 258.08,-12.53 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Feb 15 11:02:36 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     630876,   Seg_Num: 0
GRB_RA:          285.521d {+19h 02m 05s} (J2000),
                 285.627d {+19h 02m 30s} (current),
                 285.172d {+19h 00m 41s} (1950)
GRB_DEC:         +47.407d {+47d 24' 27"} (J2000),
                 +47.430d {+47d 25' 48"} (current),
                 +47.334d {+47d 20' 01"} (1950)
GRB_DATE:        17065 TJD;    43 DOY;   15/02/12
GRB_TIME:        39439.04 SOD {10:57:19.04} UT
TRIGGER_INDEX:   124
GRB_PHI:         -94.39 [deg]
GRB_THETA:        20.52 [deg]
DELTA_TIME:      320.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     18.54 [sigma]
IMAGE_SIGNIF:    7.90 [sigma]
LC_URL:          sw00630876000msb.lc
SUN_POSTN:       325.74d {+21h 42m 56s}  -13.72d {-13d 42' 58"}
SUN_DIST:         70.85 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.42d {+15h 41m 41s}  -15.77d {-15d 46' 08"}
MOON_DIST:        77.49 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      300.66, 69.20 [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 = 258.08,-12.53 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Feb 15 11:15:52 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     630876,   Seg_Num: 0
POINT_RA:        285.487d {+19h 01m 57s} (J2000)
POINT_DEC:       +47.414d {+47d 24' 52"} (J2000)
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  39792.73 SOD {11:03:12.73} UT,   353.7 [sec] since BAT Trigger Time
COUNTS:          26    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many iterations.

GCN Circular #17449
K. L. Page (U Leicester), A. Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. A. Evans (U Leicester), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester) and P. T. O'Brien (U Leicester) report on behalf of the Swift Team:
At 10:57:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150212A (trigger=630876). The Swift slew was delayed by 4.7 min due to an observing constraint. The BAT on-board calculated location is RA, Dec 285.521, +47.407 which is
```
   RA(J2000)  =  19h 02m 05s
   Dec(J2000) = +47d 24' 27"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED peak with a duration of about 10 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~1 sec after the trigger.
Due to an observing constraint, Swift did not slew until T0+4.7 minutes. By this time Swift had entered the South Atlantic Anomaly, from which it will emerge at 11:26 UT. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is K. L. Page (kpa 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:     Thu 12 Feb 15 11:45:10 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     630876,   Seg_Num: 0
POINT_RA:        285.483d {+19h 01m 56s} (J2000)
POINT_DEC:       +47.416d {+47d 24' 59"} (J2000)
POINT_ROLL:      138.393d
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  41250.75 SOD {11:27:30.75} UT,   1811.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.661
N_STARS:         123
X_OFFSET:        581 [pixels]
Y_OFFSET:        386 [pixels]
X_MAX:           1540 [pixels]
Y_MAX:           1345 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00630876000msufc1811.fits
SUN_POSTN:       325.76d {+21h 43m 03s}  -13.71d {-13d 42' 22"}
SUN_DIST:         70.88 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.81d {+15h 43m 15s}  -15.83d {-15d 49' 53"}
MOON_DIST:        77.33 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      300.60, 69.22 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 12 Feb 15 11:45:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     630876,   Seg_Num: 0
POINT_RA:        285.483d {+19h 01m 56s} (J2000)
POINT_DEC:       +47.416d {+47d 24' 59"} (J2000)
POINT_ROLL:      138.393d
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  41250.75 SOD {11:27:30.75} UT,   1811.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.661
N_STARS:         123
X_OFFSET:        581 [pixels]
Y_OFFSET:        386 [pixels]
X_MAX:           1540 [pixels]
Y_MAX:           1345 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00630876000msufc1811.fits
SUN_POSTN:       325.76d {+21h 43m 04s}  -13.71d {-13d 42' 22"}
SUN_DIST:         70.88 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.82d {+15h 43m 16s}  -15.83d {-15d 49' 57"}
MOON_DIST:        77.33 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      300.60, 69.22 [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:     Thu 12 Feb 15 11:47:34 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     630876,   Seg_Num: 0
POINT_RA:        285.483d {+19h 01m 56s} (J2000)
POINT_DEC:       +47.416d {+47d 24' 59"} (J2000)
ROLL:            138.393d
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  41250.75 SOD {11:27:30.75} UT,   1811.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     445433263
X_OFFSET:        900 [pixels]
Y_OFFSET:        705 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1060
Y_GRB_POS:       865
BINNING_INDEX:   1
IM_URL:          sw00630876000msuni1825.fits
SUN_POSTN:       325.77d {+21h 43m 04s}  -13.71d {-13d 42' 20"}
SUN_DIST:         70.88 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.83d {+15h 43m 20s}  -15.84d {-15d 50' 06"}
MOON_DIST:        77.33 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      300.60, 69.22 [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:     Thu 12 Feb 15 11:47:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     630876,   Seg_Num: 0
POINT_RA:        285.483d {+19h 01m 56s} (J2000)
POINT_DEC:       +47.416d {+47d 24' 59"} (J2000)
ROLL:            138.393d
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  41250.75 SOD {11:27:30.75} UT,   1811.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     445433263
X_OFFSET:        900 [pixels]
Y_OFFSET:        705 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1060
Y_GRB_POS:       865
BINNING_INDEX:   1
IM_URL:          sw00630876000msuni1825.fits
SUN_POSTN:       325.77d {+21h 43m 04s}  -13.71d {-13d 42' 20"}
SUN_DIST:         70.88 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.84d {+15h 43m 21s}  -15.84d {-15d 50' 08"}
MOON_DIST:        77.32 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.65, 17.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      300.60, 69.22 [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:     Thu 12 Feb 15 11:48:35 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     630876,   Seg_Num: 0
GRB_RA:          285.4809d {+19h 01m 55.41s} (J2000),
                 285.5865d {+19h 02m 20.75s} (current),
                 285.1317d {+19h 00m 31.60s} (1950)
GRB_DEC:         +47.3660d {+47d 21' 57.5"} (J2000),
                 +47.3885d {+47d 23' 18.7"} (current),
                 +47.2925d {+47d 17' 33.0"} (1950)
GRB_ERROR:       4.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17065 TJD;    43 DOY;   15/02/12
IMG_START_TIME:  41259.00 SOD {11:27:39.00} UT,   1820.0 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       325.77d {+21h 43m 04s}  -13.71d {-13d 42' 20"}
SUN_DIST:         70.84 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:      235.84d {+15h 43m 22s}  -15.84d {-15d 50' 11"}
MOON_DIST:        77.29 [deg]
MOON_ILLUM:      47 [%]
GAL_COORDS:       77.60, 17.93 [deg] galactic lon,lat of the burst
ECL_COORDS:      300.56, 69.17 [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 1.1% < P(seren) < 2.8%.

GCN Circular #17451
S. B. Cenko (NASA/GSFC) reports on behalf of a larger collaboration:
We have imaged the field of the Swift GRB150212A (Page et al., GCN 17449) with the robotic Palomar 60 inch telescope. Observations were obtained in the Sloan riz filters beginning at 11:12 UT (~ 15 min after the Swift trigger). We identify a bright source in the BAT error circle not present in archival DSS imaging of the field in all 3 filters:
```
   RA: 19:01:53.92
   Dec: +47:26:10.7
```
We measure a preliminary magnitude of r = 16.8 at ~ 15 min after the Swift trigger (calibration performed with respect to nearby point sources from the APASS catalog). While we have not yet confirmed fading, we consider this source to be the likely optical afterglow of GRB150212A.
GCN Circular #17452
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
The XRT began observing the field at 11:03:12.7 UT, 353.7 seconds after the BAT trigger. Due to passage of the spacecraft through the South Atlantic Anomaly, no XRT data were collected until T0+1805 s.
Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 285.48092, 47.36602 which is equivalent to:
```
    RA(J2000)  = 19h 01m 55.42s
    Dec(J2000) = +47d 21' 57.7"
```
with an uncertainty of 4.3 arcseconds (radius, 90% containment). This location is 176 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 5.20 x 10^20 cm^-2 (Willingale et al. 2013).
This circular is an official product of the Swift-XRT team.
GCN Circular #17454
S. B. Cenko (NASA/GSFC) reports on behalf of a larger collaboration:
We have obtained further imaging of the field the Swift GRB 150212A (Page et al., 17449) with the robotic Palomar 60 inch telescope. The candidate afterglow we previously identified (GCN 17451) has remained at a constant brightness over the course of the last hour, and is well offset from the candidate XRT afterglow (Evans et al., GCN 17452). Further inspection of archival catalogs indicates this object is likely to be a high proper motion star. We apologize for any inconvenience this may have caused.
GCN Circular #17455
M. M. Chester (Penn State), K. L. Page (U Leicester), and A. Amaral-Rogers (U Leicester) report on behalf of the Swift/UVOT team:
UVOT took a finding chart exposure of 150 seconds with the White filter starting 1811 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 none of the XRT error circle. 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 0.06.
GCN Circular #17456
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 GRB150212A (Page et. al. GCN 17449) 32 sec after notice time and 47 sec after trigger time at 2015-02-12 10:58:06 UT in two polarization. Unfortunately we were unable to obtain satisfactory data on the first images due to clouds and high zenith distance (z~75 d).
In the process of further observations we do not see the optical transient and obtained the following upper limits:
```
T_start   T-Tmid Expt.   Mlimit
11:08:50  761     140      11.5
11:11:52  958     170      11.5
11:15:26  1177    180      12.5
11:26:34  1845    180 	   12.6
11:32:12  2183    180      15.0
11:32:12  3447   1800      16.7
11:35:58  2641    540      16.1
```
So weak upper limits associated with the observation through clouds and large zenith distance of the object.
GCN Circular #17457
J. R. Cummings (GSFC/UMBC), A. Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC), W. H. Baumgartner (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), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150212A (trigger #630876) (Page, et al., GCN Circ. 17449). The BAT ground-calculated position is RA, Dec = 285.497, 47.389 deg, which is
```
   RA(J2000)  =  19h 01m 59.2s 
   Dec(J2000) = +47d 23' 19.1" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 71%.
The mask-weighted light curve is FRED peak starting at ~T-1 sec, peaking at ~T+1 sec, and ending at ~T+25 sec. T90 (15-350 keV) is 11.4 +- 4.1 sec (estimated error including systematics).
The time-averaged spectrum from T-0.20 to T+19.66 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.50 +- 0.11. The fluence in the 15-150 keV band is 8.9 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.82 sec in the 15-150 keV band is 1.9 +- 0.2 ph/cm2/sec. 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/630876/BA/
GCN Circular #17458
A. Trotter, D. Reichart, A. LaCluyze, J. Haislip, A. Smith, D. Caton, L. Hawkins, K. McLin, L. Cominsky, A. Aji, T. Berger, A. Dow, A. Foster, N. Frank, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, C. Salemi, and J. A. Crain report:
Skynet observed the Swift BAT/XRT localization of GRB 150212A (Page et al., GCN 17449, Swift trigger=630876) with the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO14) in NC, USA, and with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume Observatory in CA, USA. DSO14 obtained exposures of the field starting at 2015-02-12 10:58:05 (t=46s post-trigger); GORT was delayed until 48m post-trigger due to clouds. Skynet took a total of 29 exposures ranging from 5s to 160s in the R and I bands. We do not detect any optical source at the XRT afterglow position reported by Evans (GCN 17452).
Our early-time DSO14 limiting magnitudes are:
```
==============================================
tmid    scope   band    exposures   lim mag
----------------------------------------------
48s     DSO14    I      1 x 5s      >15.2
102s    DSO14    I      2 x 10s     >16.4
108s    DSO14    R      1 x 5s      >16.0
==============================================
```
Stacked subsets of those images that maximize the S/N ratio give limiting magnitudes:
```
==============================================
tmid    scope   band    exposures   lim mag
----------------------------------------------
15.4m   DSO14    R      1 x 80s      >18.4
                        1 x 160s
16.1m   DSO14    I      1 x 80s      >18.4
                        1 x 160s                       
74m     GORT     R      4 x 160s     >17.2
84m     GORT     I      3 x 160s     >16.8
==============================================
```
Magnitudes are in the Vega System, calibrated to 10 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.051 (Schlafly & Finkbeiner 2011).
No further Skynet observations are scheduled.
GCN Circular #17459
E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I.Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of 150212A (Page et al., GCN 17449) with ORI-40 telescope of Khureltogot observatory on Feb., 12 starting on (UT) 11:32:28. We obtained 24 unfiltered images of 15 s exposure. We did not detect any optical counterpart in XRT error circle (Evans et al. GCN 17452). Details of the photometry are following:
```
Date        UT start  t-T0    Filter Exp.  uplim (3 sigma)
                       (mid, days) (s)

2015-02-12  11:32:28  0.02739 none  24*15  15.8
```
The star mentioned by Cenko et al. (GCNs 17451, 17454) is visible in our combined image and have a brightness of 15.85 +/- 0.25.
The photometry is based on R magnitudes of nearby USNO-B1.0 stars
```
USNO-B1_id    R2
1374-0373548  15.39
1374-0373502  14.41
```
GCN Circular #17460
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m 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), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 150212A (Page, et al., GCN 17449) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2015/02 12.51 to 2015/02 12.55 UTC (1.29 to 2.31 hours after the BAT trigger), obtaining a total of 0.89 hours exposure in the r, i, and z bands.
We find one uncatalogued source within the Swift XRT error circle (Evans, et al., GCN 17452) at a position RA, Dec =3D 285.48273, 47.36637 (+/- 0.5", J2000) with magnitudes r =3D 23.1 +/- 0.4 and i =3D 21.4 +/- 0.1. This source does not appear to fade in time during our observation. For other potential sources within the XRT error circle, in comparison with USNO-B1 and 2MASS, we obtain the following upper limits (3-sigma):
```
  r > 23.1
  i > 23.3
  z > 19.6
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #17462
A. Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU), J.A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of the Swift-XRT team:
We have analysed 4.1 ks of XRT data for GRB 150212A (Page et al. GCN Circ. 17449), from 1.8 ks to 54.6 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 285.4799, +47.3656 which is equivalent to:
```
RA (J2000): 19 01 55.16
Dec(J2000): +47 21 56.3
```
with an uncertainty of 3.7 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.56 (+0.15, -0.14).
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). The best-fitting absorption column is 1.7 (+1.2, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 5.2 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 3.0 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.7 (+1.2, -1.0) x 10^21 cm^-2
Galactic foreground: 5.2 x 10^20 cm^-2
Excess significance: 2.0 sigma
Photon index:	     2.3 (+/-0.4)
```
If the light curve continues to decay with a power-law decay index of 0.56, the count rate at T+24 hours will be 0.012 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.5 x 10^-13 (5.2 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00630876.
This circular is an official product of the Swift-XRT team.
GCN Circular #17466
M. H. Siegel, M. M. Chester (PSU), A. Amaral-Rogers (U Leicester) and D. Malesani (DARK/NBI) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150212A 1812 s after the BAT trigger (Page et al. GCN Circ. 17449; Chester et al. GCN Circ. 17455). A cataloged optical source is detected within the XRT error circle (Evans GCN Circ. 17452). The measured magnitudes are consistent with the cataloged values and no fading is evident.
GCN Circular #17473
V.V. Golovnya (Main Astro Obs., Kyiv) report:=20 We have undertaken the review of the sky area of GRB 150212A (P.A. Evans GCN Circ. 17452) on astronegatives, collected in Ukrainian plate archive (1976-1996). All the plates with the possible object appearance are digitized using Epson Expression 10000XL flatbed scanner and the images have been placed into Golosiiv Plate Archive database DBGPA with open access to them. The list of plates is given in the table:
```
yyyymmdd/TimeUT   ---Plates----- Exp. -Mag- --USNO-B1--
19840720/21:19:40 GUA040C000430A 22.5 15.93 1373-0374987
19770622/22:14:06 GUA040C000535B 60.0 17.17 1374-0373547
19860716/21:18:54 GUA040C000961  16.0 17.42 1373-0374984
19870701/22:16:16 GUA040C001064  16.0 17.42 1373-0374984
19870822/19:11:46 GUA040C001078A 16.0 16.33 1373-0374866
```
Plates:=E2=80=93the plates archive identifier of DWA D/F=3D400/2000, M= 103"/mm (Marsden's number - 83) the plate number [1]. Exp. - Duration of the maximum exposures (minutes). Mag - Limited Bmag, derived in the 7 minutes area around the location given in Evans GCN Circ. 17452: RA(J2000): 19h 01m 55.27s, Dec(J2000): +47d 21' 57.6". USNO-B1 - Comparison star. The preview images of 5 areas together with the 7 min. of arc area from Aladin can be found in "http://gua.db.ukr-vo.org/img/grb/150212A/index.html". The images with full resolution are available via e-mail on demand.
References: 1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0), "http://gua.db.ukr-vo.org".

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Jochen Greiner, last update: 14-Feb-2015 [Disclaimer]