GRB 190511A
GCN Circular 24587
Subject
GRB 190511A: Swift/UVOT further analysis
Date
2019-05-17T20:15:07Z (7 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and M. G. Bernardini (INAF-OAB)
report on behalf of the Swift/UVOT team:
In GCN Circ. 24494 (Kuin and Bernardini) we described how we detect
the afterglow of the GRB, but that the photometry was affected by
an object located at a distance of 1.3 arcsec. Further Swift
observations show that the uv-optical afterglow was no longer
detected in white beyond 26ks after the trigger. Data that were taken
after that time are considered template observations that
provide the background contribution to the photometry.
The template net corrected count rates, with instrumental effects
removed, are found to be as follows for a 3" radius circular aperture
at the location of the GRB as reported in GCN 24494:
White = 1.066 +/- 0.031 c/s; u = 0.149 +/- 0.016 c/s;
b = 0.509 +/- 0.061 c/s; uvw2 = 0.011 +/- 0.011 c/s;
v = 0.272 +/- 0.042 c/s; while uvm2 and uvw1 were not observed
until after the afterglow became too faint.
After removal of the template contribution, the following preliminary
detections and 3-sigma upper limits were determined from the count rates
using the zeropoints in the UVOT photometric system (Poole et al. 2008,
MNRAS 383, 627; Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for
the image mode exposures:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 131 281 147 15.96 +/- 0.05
u 290 385 93 19.62 +/- 0.42
b 5684 5884 197 > 20.13
white 5888 6088 197 20.61 +/- 0.37
uvw2 6094 11850 518 > 17.81
v 17150 17450 300 > 19.35
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 24534
Subject
Konus-Wind observation of GRB 190511A
Date
2019-05-14T10:00:01Z (7 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 190511A
(Swift-BAT detection: Bernardini et al., GCN Circ. 24472,
Barthelmy et al., GCN Circ. 24502;
Fermi-GBM observation: Kienlin et al., GCN Circ. 24482;
Fermi-LAT detection: Axelsson et al., GCN Circ. 24483)
triggered Konus-Wind at T0=26067.524 s UT (07:14:27.524).
The burst light curve shows a multipeaked structure
which started at ~T0-2.6 s and had a total duration of ~31.8 s.
The emission is seen up to ~2 MeV.
As observed by Konus-Wind, the burst
had a fluence of 1.93(-0.11,+0.12)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+21.936 s,
of 3.81(-0.90,+0.91)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+33.024 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.69(-0.16,+0.17)
and Ep = 185(-15,+18) keV (chi2 = 49/58 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.4
(chi2 = 48/57 dof)
The spectrum near the maximum count rate
(measured from T0+16.640 to T0+24.832 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model
with alpha = -0.52(-0.23,+0.26)
and Ep = 193(-20,+26) keV (chi2 = 53/58 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 53/57 dof)
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190511_T26067/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 24502
Subject
GRB 190511A: Swift-BAT refined analysis
Date
2019-05-12T16:15:20Z (7 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 190511Atrigger #903158)
(Bernardini, et al., GCN Circ. 24472). The BAT ground-calculated position is
RA, Dec = 126.443, -20.252 deg which is
RA(J2000) = 08h 25m 46.2s
Dec(J2000) = -20d 15' 05.6"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 9%.
The mask-weighted light curve shows a complex, multi-peaked structure,
starting at about T-25 sec, peaking at T+0 sec and declining to background
by T+10 sec. The spacecraft slewed away from the burst position by
T+475 sec. T90 (15-350 keV) is 27.7 +- 2.4 sec (estimated error including
systematics).
The time-averaged spectrum from T-24.27 to T+6.88 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.19 +- 0.10. The fluence in the 15-150 keV band is 7.4 +- 0.5 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.36 sec in the 15-150 keV band
is 6.2 +- 1.2 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/903158/BA/
GCN Circular 24498
Subject
GRB 190511A: Swift-XRT refined Analysis
Date
2019-05-12T07:42:36Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernadini
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU),
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U.
Leicester) and M.G. Bernardini report on behalf of the Swift-XRT team:
We have analysed 4.0 ks of XRT data for GRB 190511A (Bernardini et al.
GCN Circ. 24472), from 129 s to 46.3 ks after the BAT trigger. The
data comprise 188 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 24481).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.177 (+0.031, -0.028).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.07 (+0.08, -0.07). The
best-fitting absorption column is consistent with the Galactic value
of 1.1 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 2.12 (+0.24, -0.23) and a best-fitting absorption
column of 1.6 (+0.7, -0.5) x 10^21 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.2 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.6 (+0.7, -0.5) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.12 (+0.24, -0.23)
If the light curve continues to decay with a power-law decay index of
1.177, the count rate at T+24 hours will be 9.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x
10^-13 (4.2 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/00903158.
This circular is an official product of the Swift-XRT team.
GCN Circular 24494
Subject
GRB 190511A: Swift/UVOT Detection
Date
2019-05-11T23:50:25Z (7 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL), M. de Pasquale (U. of Istanbul) and
M. G. Bernardini (INAF-OAB) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190511A
131 s after the BAT trigger (Bernardini et al., GCN Circ. 24472).
A source consistent with the XRT position
(Goad et al. GCN Circ. 24481)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 08:25:46.44 = 126.44350 (deg.)
Dec (J2000) = -20:15:33.6 = -20.25933 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
There is a catalogued star at a distance of 1.3 arcsec. The extrapolated
brightness using the SED from the Vizier photometry tool
(
http://cdsportal.u-strasbg.fr/gadgets/ifr?url=http://cdsportal.unistra.fr/widgets/SED_plotter.xml&SED_plot_object=126.442680%2C%20-20.259685&SED_plot_radius=2
)
shows a brightness consistent with that of the white count rate seen at
several
ks after the trigger. We subtract here therefore the late time count rate
in the
following preliminary UVOT photometry of this GRB, knowing that this has to
be
refined using truely late time data. Where we did not have a late time
measurement yet available, the photometry will be reported in due time.
Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 131 281 147 16.0 +/- 0.1
b 5684 5884 197 21.6 +/- 0.3
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).
The afterglow was also discovered by NOT (Malasani et al. GCN Circ. 24492).
GCN Circular 24492
Subject
GRB 190511A: NOT optical afterglow
Date
2019-05-11T22:13:23Z (7 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
Daniele B. Malesani (DAWN/NBI and DARK/NBI), Dong Xu (NAOC/CAS), Joonas
Viuho (NOT and DAWN/NBI) report on behalf of a larger collaboration:
We observed the field of the Swift and Fermi GRB 190511A (Bernardini et
al., GCN 24472; von Kienlin, GCN 24482; Axelsson et al., GCN 24483)
using the Nordic Optical Telescope (NOT) equipped with the AlFOSC
camera. Observations started in twilight and were carried out at high
airmass due to the poor target visibility.
Just outside the enhanced XRT error position (Goad et al., GCN 24481),
we clearly detect a source not visible in the archival Pan-STARRS images
of the same area, which we suggest to be the optical afterglow of GRB
190511A. Its coordinates are (J2000):
RA = 08:25:46.46
Dec = -20:15:33.4
Using nearby stars from the Pan-STARRS survey as calibrators, we measure
for the afterglow a magnitude r = 20.89 +- 0.09 AB, at a mean epoch May
11.8648 UT (13.51 hr after the trigger).
GCN Circular 24483
Subject
GRB 190511A: Fermi-LAT detection
Date
2019-05-11T13:15:11Z (7 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
M. Axelsson (KTH and Stockholm Univ.), F. Longo (Univ. and INFN Trieste), M. Arimoto (Kanazawa Univ.) and F. Dirirsa (Univ. of Johannesburg) report on behalf of the Fermi-LAT team:
On May 11, 2019, Fermi-LAT detected high-energy emission from GRB 190511A, which was also detected by Fermi-GBM (trigger 579251669 / 190511302; GCN 24482) and Swift (GCNs 24472 and 24481).
The best LAT on-ground location is found to be
RA, Dec 126.36, -20.25 (degrees, J2000)
with an error radius of 0.2 deg (90% containment, statistical error only).
This was 24 deg from the LAT boresight at the time of the GBM trigger:
T0 = 07:14:24.36 UT.
The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially correlated with the GBM emission with high significance and consistent with the Swift location.
The photon flux above 100 MeV in the time interval 0-1400s after the GBM trigger is 3.6e-6 ph/cm2/s.
The estimated photon index above 100 MeV is -2.0 +/- 0.2.
The Fermi-LAT point of contact for this burst is Feraol Dirirsa (fdirirsa@uj.ac.za<mailto:fdirirsa@uj.ac.za>).
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.
GCN Circular 24482
Subject
GRB 190511A: Fermi GBM observation
Date
2019-05-11T12:43:21Z (7 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 07:14:24.36 UT on 11 May 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190511A (trigger 579251669 / 190511302),
which was also detected by the Swift/BAT (Bernardiniet al. 2019, GCN 24472)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 23.7 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of a multipeaked emission episode with
a duration (T90) of about 28 s (50-300 keV).
The time-averaged spectrum from T0-2.048 s to T0+31.745 s is
best fit by a Band function with Epeak = 147.8 +/- 7.2 keV,
alpha = -0.58 +/- 0.05, and beta = -2.4 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is
(2.21 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+24.1924 s in the 10-1000 keV band
is 14.2 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 24481
Subject
GRB 190511A: Enhanced Swift-XRT position
Date
2019-05-11T12:08:39Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 411 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 190511A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 126.44426, -20.25935 which is equivalent
to:
RA (J2000): 08h 25m 46.62s
Dec (J2000): -20d 15' 33.7"
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 24472
Subject
GRB 190511A: Swift detection of a burst
Date
2019-05-11T07:42:00Z (7 years ago)
From
Boris Sbarufatti at PSU <bxs60@psu.edu>
M. G. Bernardini (INAF-OAB), H. A. Krimm (NSF/USRA),
N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester),
B. Sbarufatti (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 07:14:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190511A (trigger=903158). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 126.436, -20.242 which is
RA(J2000) = 08h 25m 45s
Dec(J2000) = -20d 14' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec. The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 07:16:51.2 UT, 122.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 126.44482, -20.25978 which
is equivalent to:
RA(J2000) = 08h 25m 46.76s
Dec(J2000) = -20d 15' 35.2"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 70 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
The initial flux in the 2.5 s image was 9.43e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 95 seconds with the U filter starting
290 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.09.
Burst Advocate for this burst is M. G. Bernardini (grazia.bernardini AT brera.inaf.it).
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/)
GCN Circular 24471
Subject
GRB 190511A: Fermi GBM Final Real-time Localization
Date
2019-05-11T07:25:58Z (7 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 07:14:24 UT on 11 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190511A (trigger 579251669.35821 / 190511302).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 123.8, Dec = -24.3 (J2000 degrees, equivalent to J2000 08h 15m, -24d 18'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 19.0 degrees.
The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_skymap_all_bn190511302.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_healpix_all_bn190511302.fit
The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_lc_medres34_bn190511302.gif