GRB 220412B

J.D. Gropp (PSU), S. Dichiara (PSU), J. A. Kennea (PSU),
N. J. Klingler (GSFC/UMBC/CRESSTII), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), T. M. Parsotan (GSFC/UMBC/CRESSTII),
B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 17:06:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220412B (trigger=1102329).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 320.794, -0.223 which is 
   RA(J2000) = 21h 23m 11s
   Dec(J2000) = -00d 13' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 0.5 sec.  The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 17:08:13.7 UT, 85.0 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 130 seconds with the White filter
starting 89 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 25% of
the BAT 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
BAT 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
0.060. 

Shortly after the BAT trigger, Swift entered the South Atlantic Anomaly which 
limited data collection for the first orbit. We are awaiting further observations. 

Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 
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/)

K. L. Murata, M. Niwano, Y. Imai, N. Ito, Y. Takamatsu, S. Sato, R.
Hosokawa, M. Sasada, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 220412B (Gropp et al. GCN Circular #31886
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 )
with the optical three color (g', Rc, and Ic) CCD cameras attached to the
MITSuME 50 cm telescope Akeno. The observation with a series of 60 sec
exposures started at 2022-04-12 18:28:16 UT (82 minutes after the Swift/BAT
trigger). We stacked the images with good conditions. We did not detect any
uncatalogued sources within the BAT error region (Gropp et al. GCN Circular
#31886
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 ). We obtained the 5-sigma limits of the stacked images as follows.

T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
82 2022-04-12 18:55:21 2820 g'>17.9, Rc>19.0, Ic>18.5
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration. The magnitudes are expressed
in the AB system. The images were processed in real-time through the
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1,
Pages 4-24; https://github.com/MNiwano/Eclaire).

H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), G. C. Anupama (IIA), V.
Bhalerao (IITB), S. Barway (IIA) report on behalf of the GIT team:

We observed the short GRB 220412B detected by Swift-BAT (J.D. Gropp et al.,
GCN #31886
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 ) with the 0.7m *GROWTH-India Telescope* (GIT). We obtained multiple
300-sec exposures in the r' filter. We did not detect any new source in our
stacked image within the BAT uncertainty region of 3 arcmin circle, around
R.A.= 320.794, DEC.= -0.223. The obtained upper limit follows as:

-------------------------------------------------------------------------

 JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |

-------------------------------------------------------------------------

2459682.452891 | 5.75 | 300 x 6 (stacked) | r' | > 20.25 |

-------------------------------------------------------------------------

Our upper limit is consistent with results from K. L. Murata et al. (GCN
#31889
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 ). The magnitudes are calibrated against Pan-STARRS DR1 (Chambers et
al., 2016) and not corrected for Galactic extinction.

The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics (IIA) and the
Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and
IUSSTF. It is located at the Indian Astronomical Observatory (Hanle),
operated by IIA. We acknowledge funding by the IITB alumni batch of 1994,
which partially supports operations of the telescope. Telescope technical
details are available at https://sites.google.com/view/growthindia/.

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) was pointed to the Swift GRB 220412B ( J.D. Gropp et al., GCN 31886
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 ) errorbox  61446 sec after notice time and 61475 sec after trigger time at 2022-04-13 10:11:24 UT, with upper limit up to  17.5 mag. The observations began at zenith distance = 77 deg. The sun  altitude  is -32.6 deg. 

The galactic latitude b = -34 deg., longitude l = 53 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1940975

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   61505 |         MASTER-OAGH |   C |    60 | 17.5 |        
   61505 |         MASTER-OAGH |   C |    60 | 17.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), J. D. Gropp (PSU),
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB) and
J.D. Gropp (PSU) report on behalf of the Swift-XRT team:

We have analysed 7.8 ks of Photon Counting (PC) mode XRT data for the
Swift-BAT-detected burst GRB 220412B (Gropp et al. GCN Circ. 31886
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 ),
collected between T0+4.7 ks and T0+29.1 ks. 

No X-ray sources have been detected consistent with being within 296
arcsec of the Swift-BAT position. The 3-sigma upper limit in the field
is 0.001 ct  s^-1, corresponding to a 0.3-10 keV observed flux of
4.2e-14 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

Four uncatalogued sources were detected too far from the GRB position
to be likely afterglow candidates.

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/01102329.

This circular is an official product of the Swift-XRT team.

Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC),  C. Perez del Pulgar,  A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:

Following the detection of short GRB 220412B by Swift (Gropp et al., GCNC 31886), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst on Apr 13 at 03:46 UT (~10.7 hours after trigger). In the co-added frame (45 x 60 s, clear filter), no source is detected within the BAT error box (Gropp et al., GCNC 31886) down to 18.8 mag, which is consistent with the non-detections reported by UVOT (Gropp et al., GCNC 31886), MITSuME (Murata et al. GCNC 31889), GIT (Kumar et al. GCNC 31892) and MASTER (Lipunov et al., GCNC 31894).

We thank the staff at INTA-CEDEA for their excellent support.

P. D'Avanzo (INAF-OAB), S. Piranomonte (INAF-OAR), L. Di Fabrizio, H. Stoev (INAF-TNG) on behalf of the CIBO collaboration report:

We observed the field of the short GRB 220412B (Gropp et al. GCN Circ. 31886
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 ) with the Italian 3.6m TNG telescope equipped with the 
optical camera DOLORES. A series of images were obtained with the r-sdss filter on 2022-04-13 from 04:42:48 UT to 05:26:37 UT 
(i.e. at a mid time of about 12 hours after the burst).  

No clear afterglow candidate is detected within the BAT error (Gropp et al. GCN Circ. 31886
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 ). The typical 3sigma limiting magnitude of 
our co-added image for isolated objects is r ~ 24.2 mag (AB; calibrated against the SDSS catalogue).

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 17:06:49.04 UT on 12 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220412B (trigger 671476014 / 220412713)
which was also detected by the Swift/BAT (Gropp et al., GCN 31886
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 ).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 20 degrees.


The GBM light curve consists of a single pulse
with a duration (T90) of about 0.16 s (50-300 keV).
The time-averaged spectrum from T0-32 ms to T0+96 ms is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.70 +/-0.14 and
the cutoff energy, parameterized as Epeak, is 499 +/- 116 keV.

The event fluence (10-1000 keV) in this time interval is
(4.44 +/- 0.40)E-7 erg/cm^2. The 64-ms peak photon flux measured
starting from T0 in the 10-1000 keV band
is 17.2 +/- 1.2 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko,
A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report:

The short-duration GRB 220412B
(Swift-BAT detection: Gropp et al., GCN Circ. 31886
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 ;
Fermi-GBM observation: Veres and Meegan, GCN Circ. 31908
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 )
triggered Konus-Wind at T0=26885.231 s UT (07:28:05.231).

The burst light curve shows a single pulse
with a total duration of ~86 ms.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220412_T61606/

As observed by Konus-Wind, the burst
had a fluence of 3.2(-0.1,+1.2)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-42 ms,
of 1.1(-0.1,+0.4)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-52 ms to T0+34 ms)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.03(-0.47,+0.59) and Ep = 283(-52,+68) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), 

H. A. Krimm (NSF), S. Laha (GSFC/UMBC),

A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),

D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),

M. Stamatikos (OSU) (i.e. the Swift-BAT team):

 

Using the data set from T-240 to T+40 sec sec from the recent telemetry downlink,

we report further analysis of BAT GRB 220412B (trigger #1102329)

(Gropp et al. GCN Circ. 31886
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 ).  The BAT ground-calculated position is

RA, Dec = 320.758, -0.261 deg which is 

   RA(J2000)  =  21h 23m 01.9s 

   Dec(J2000) = -00d 15' 38.5" 

with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 75%.

 

The BAT light curve showed a single-peaked

structure. T90 (15-350 keV) is 0.14 +- 0.04 sec 

(estimated error including systematics).

 

The time-averaged spectrum from T-0.03 to T+0.16 sec is best fit by a simple

power-law model.  The power law index of the time-averaged spectrum is

1.17 +- 0.20.  The fluence in the 15-150 keV band is 8.9 +- 1.2 x 10^-08 erg/cm2.

The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band

is 1.0 +- 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/1102329/BA/

M. H. Siegel and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220412B
89 s after the BAT trigger (Gropp et al., GCN Circ. 31886
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 ).
No optical afterglow consistent with the BAT position
(Sakamoto et al., GCN Circ. 31910
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 ) 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 (fc)          89          217          128         >20.0
white             4378         4577          197         >20.3
b                 4173         4373          197         >19.8
u                 3968         4167          197         >19.4
w2                4584         4663           78         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.060 in the direction of the burst
(Schlegel et al. 1998).