GRB 180914A

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long GRB 180914A (Fermi-LAT detection:
Bissaldi, Kocevski & Omodei , GCN 23225
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 ;
Fermi GBM detection: Poolakkil, Meegan & Bissaldi, GCN 23227
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 ;
IPN Triangulation: Hurley et al., GCN 23247
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 ;
AstroSat CZTI detection: Sharma at al., GCN 23248
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 )
triggered Konus-Wind at T0=45119.268 s UT (12:31:59.268).

The burst light curve shows multiple pulses
in the interval from T0 - 11 s to T0+143 s.
A total duration of the burst (T100) is ~154 s.
The emission is seen up to ~20 MeV.

As observed by Konus-Wind, the burst
had a fluence of 9.08(-0.51,+0.57)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+13.408 s,
of 6.05(-1.28,+1.29)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+147.200 s)
is best fit in the 20 keV - 20 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -0.68(-0.12,+0.13),
and Ep = 301(-25,+30) keV (chi2 = 136/98 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.43 (chi2 = 134/97 dof).

The spectrum near the peak count rate
(measured from T0+7.936 to T0+16.128 s)
is best fit in the 20 keV - 20 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -0.51(-0.13,+0.14),
and Ep = 356(-31,+37) keV (chi2 = 112/98 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.82 (chi2 = 112/97 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180914_T45119/

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

V. Sharma, T. Khanam and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 180914A, which was also detected by Fermi (LAT: Bissaldi E. et al., GCN 23225
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  and GBM: Poolakkil S. et al., GCN 23227
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 ), Swift (XRT: D'Elia V. et al., GCN 23229
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 ) and IPN Triangulation (Hurley K. et al., GCN 23247
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 ).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 12:32:08.500 UT. The measured peak count rate is 874 cts/s above the background in combined data of four quadrants, with a total of 27940 cts. The local mean background count rate was 609 cts/s. Using cumulative rates, we measure a T90 of 125.4 s. In preliminary analysis, we find that 2142 compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

The long-duration GRB 180914A (Bissaldi et al., GCN Circ.23225
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 ;
Poolakkil et al., GCN Circ. 23227
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 ) was detected by
Fermi (GBM trigger 558621112), INTEGRAL (SPI-ACS), Konus-Wind,
and Mars-Odyssey (HEND) at about 45107 s UT (12:31:47).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    53.107 (03h 32m 26s)  -5.687 ( -5d 41' 14")
  Corners:
    52.535 (03h 30m 08s)  -5.415 ( -5d 24' 53")
    53.948 (03h 35m 48s)  -8.072 ( -8d 04' 21")
    53.677 (03h 34m 42s)  -5.954 ( -5d 57' 13")
    52.197 (03h 28m 47s)  -3.090 ( -3d 05' 23")
  ---------------------------------------------
The error box area is 2.36 sq. deg, and its maximum
dimension is 5.28 deg (the minimum one is 45.48 arcmin).
The Sun distance was 119 deg.

This box may be improved.

The distance between the XRT source (D'Elia et al., GCN circ. 23229
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 ) and 
the box center is 4.1 arcmin, supporting the association of the 
transient and the GRB.

We thank Robert Wilson for noticing this.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180914_T45107/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.

Eleonora Troja (GSFC), Alan M. Watson (UNAM), Nat Butler (ASU),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),
Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jesus Gonzalez (UNAM), Carlos Roman-Zuniga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.),
and Vicki Toy (UMD) report:

We observed the field of the LAT GRB 180914A (Bissaldi, et al., GCN
23225
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 ) with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astronomico Nacional on Sierra San Pedro Martir from 2018/09 15.29 to
2018/09 15.50 UTC (18.54 to 23.57 hours after the Fermi trigger),
obtaining a total of 3.00 hours exposure in the r and i bands and
1.24 hours exposure in the Z, Y, J, and H bands.

For a source within the Swift-XRT error circle (D'Elia, et al.,
GCN 23229
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 ), in comparison with the SDSS DR9 and 2MASS catalogs, we
obtain the following upper limits (3-sigma):

   r    > 24.2
   i    > 24.1
   Z    > 22.7
   Y    > 22.5
   J    > 22.0
   H    > 21.6

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 Astronomico Nacional in San Pedro
Martir.

V. Lipunov, E. Gorbovskoy, D. Vlasenko, N.Tiurina,
V.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov,
Lomonosov Moscow State University,SAI

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

D.Svinkin (Ioffe Institute, Sankt Petersburg)

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located near 
Bykal Lake (Irkutsk University Astrophysical Center) was starting survey
on the FERMI  GRB180914.52  error-box  (Poolakkil et al., GCN #23227
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 ).

17768 sec after trigger time at 
2018-09-14 17:27:55 UT. The 5-sigma upper limit on our first (180s 
exposure)  set is about 16.0 mag

No OT found.

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was starting survey 
on the LAT  GRB180914.52  error-box (ra=03 30 
57 dec=-05 15 35 r=0.4, (Bissaldi et al., GCN #23225
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 )). 
15521 sec after notice time and 38331 sec after trigger time at 2018-09-14 
23:10:38 UT. The 5-sigma upper limit on our first (180s exposure)  set is 
about 18.5 mag

The cover map is available at 
http://observ.pereplet.ru/images/GRB180914A.png

No new objects brighter than 18.5 mag  were found after the human analysis 
of automatic candidates.


====================================================================


The galacitc latitude b =  0 deg.

The observations made on zenit distance = 54 deg.The moon (31 % bright 
part) below the horizon (The altitude of the Moon is -19 deg. ).
The sun  altitude  is -59.4 deg.
The object can be observed till sunrise at 2018-09-15 04:35:52



THIS BLOCK FOR MASTER-Team USERS ONLY.

Link to GRB180914.52 page: 
https://196.21.94.34//master2/grb.php?not=2018-09-14+18%3A51%3A56.63329&sat=LAT&gcrd=%2852.7375d%2C-5.25972d%29&eb=0.4&trig=2018-09-14+12%3A31%3A47.25&n=GRB180914.52
Long     transients in E.B. 
https://196.21.94.34//master2/trans.php?wh=transients.coord2000@%27%3C%2852.7375d%2C-5.25972d%29%2C0.8d%3E%27%3A%3Ascircle+and+transients.datetime%3E%3D%272018-09-14+12%3A31%3A47.25%27&class=9&t2=LAT+GRB180914.52+optical+counterpart+candidate
Short    transients in E.B. 
https://196.21.94.34//master2/trans3.php?wh=transients3.coord2000@%27%3C%2852.7375d%2C-5.25972d%29%2C0.8d%3E%27%3A%3Ascircle+and+transients3.datetime%3E%3D%272018-09-14+12%3A31%3A47.25%27&class=-1&t2=LAT+GRB180914.52+optical+counterpart+candidate
Two tube transients in E.B. 
https://196.21.94.34//master2/trans2.php?wh=transients2.coord2000@%27%3C%2852.7375d%2C-5.25972d%29%2C0.8d%3E%27%3A%3Ascircle+and+transients2.datetime%3E%3D%272018-09-14+12%3A31%3A47.25%27&class=0&t2=LAT+GRB180914.52+optical+counterpart+candidate
Undef. objects 1 image 
https://196.21.94.34//master2/aobj.php?wh=stars.coord2000@%27%3C%2852.7375d%2C-5.25972d%29%2C0.8d%3E%27%3A%3Ascircle+and+stars.class=0+and+stars.status+and+stars.proc_id=578290&t2=LAT+GRB180914.52+1+image+optical+counterpart+candidate

This message can be cited

V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), A.
Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), S.L. Gibson
(U. Leicester), Z. Liu (NAOC / U. Leicester) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 180914A (Bissaldi et al. GCN Circ. 23225
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 )
in a series of observations tiled on the sky. The total exposure time
is 1.8 ks, distributed over 7 tiles; the maximum exposure at a single
sky location was 546 s. The data were collected between T0+40.9 ks and
T0+43.0 ks, and are entirely in Photon Counting (PC) mode. 

One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:

Source 1:
  RA (J2000.0):  53.0804  =  03:32:19.29
  Dec (J2000.0): -5.6243  =  -05:37:27.5
  Error: 5.0 arcsec (radius, 90% conf.)
  Count-rate: 0.162 [+0.048, -0.040] ct s^-1   
  Distance: 1791 arcsec from Fermi/LAT position.
  Flux: (7.7 [+2.3, -1.9])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

We note the presence of a bright star (with magnitude R~12.7, as
reported in the USNOB1 catalogue) about 14" away from Source 1.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00074.

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

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
Fermi/LAT GRB 180914A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00074

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Fermi/LAT event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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

S.Poolakkil(UAH), C. Meegan (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 12:31:47.25 UT on 14 September 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180914A (trigger 558621112/ 180914522),
which was also detected by the Fermi LAT (E. Bissaldi et al. 2018, GCN
23225
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 ).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 86 degrees.

The GBM light curve shows multiple peaks
with a duration (T90) of about 122.4 s (50-300 keV).
The time-averaged spectrum from T0+1.0 s to T0+156.7 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.70 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 296 +/- 7 keV.

The event fluence (10-1000 keV) in this time interval is
(9.152 +/- 0.128)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+21.37 s in the 10-1000 keV band
is 12.73 +/- 0.36 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

E. Bissaldi (Politecnico & INFN Bari), D. Kocevski (NASA/MSFC),
and N. Omodei (Stanford Univ) report on behalf of the Fermi-LAT team:


At 12:31:47.25 UT on September 14, 2018 Fermi-LAT detected
high-energy emission from GRB 180914A, which was also detected by
Fermi-GBM (trigger 558621112 / 180914522).

The best LAT on-ground location is found to be

RA, Dec = 52.74, -5.26 (J2000)

with an error radius of 0.40 deg (90 % containment,
statistical error only). This was 87 deg from the LAT boresight
at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event
rate that is spatially correlated with the trigger with high significance.
The highest-energy photon is a 5.1 GeV event which is
observed 630 s after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).


The Fermi-LAT is a pair conversion telescope designed to cover
the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between
NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.