| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
19:46:13 UTC |
GCN_circulars,Swift Det |
| ra |
331.1438° |
Swift |
| decl |
-14.6587° |
Swift |
| pos_error |
1.94e-04° |
Swift |
| T90 |
88.3 s |
Swift |
| T90_start |
19:46:13 UTC |
Swift |
| fluence |
2.20e-06 erg/cm² |
Swift |
| T100 |
88.3 s |
|
| GBM_located |
False |
|
| mjd |
58242.82376157407 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB180504A |
| ra |
331.1417° |
| decl |
-14.6667° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB180504A |
| t_trigger |
19:46:13 UTC |
| ra |
331.1438° |
| decl |
-14.6587° |
| pos_error |
1.94e-04° |
| T90 |
88.3 s |
| fluence |
2.20e-06 erg/cm² |
| GCN 22682 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22682 |
| Detection_method |
Swift Det |
| t_trigger |
19:46:13 UTC |
| ra |
331.1340° |
| decl |
-14.6550° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22682
SUBJECT: GRB 180504A: Swift detection of a burst
DATE: 18/05/04 20:03:11 GMT
FROM: Amy Lien at GSFC
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),
A. Tohuvavohu (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 19:46:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180504A (trigger=830822). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 331.134, -14.655 which is
RA(J2000) = 22h 04m 32s
Dec(J2000) = -14d 39' 17"
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 50 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger.
Using promptly downlinked data we find a bright, uncatalogued X-ray
source located at RA, Dec 331.14235, -14.65988 which is equivalent to:
RA(J2000) = 22h 04m 34.16s
Dec(J2000) = -14d 39' 35.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). 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 consistent with the Galactic value of 3.50
x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 9.57e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 117 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
0.04.
Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov).
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 22683 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22683 |
| Detection_method |
Swift-XRT Other |
| ra |
331.1442° |
| decl |
-14.6583° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22683
SUBJECT: GRB 180504A: Prompt enhanced Swift-XRT position
DATE: 18/05/04 20:28:42 GMT
FROM: Phil Evans at U of Leicester
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 180504A, we find an
enhanced XRT position of the afterglow: RA, Dec: 331.1442, -14.6583
which is equivalent to:
RA (J2000) = 22 04 34.61
Dec (J2000) = -14 39 30.0
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/830822.
Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
|
| GCN 22684 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22684 |
| Detection_method |
Other |
| ra |
331.1442° |
| decl |
-14.6583° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22684
SUBJECT: GRB 180504A: NOT afterglow candidate
DATE: 18/05/05 07:05:30 GMT
FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst
D. Malesani (DAWN/NBI and DARK/NBI) and Illa R. Losada (NOT, Nordita,
Stockholm Univ.) report on behalf of a larger collaboration:
We observed the field of GRB 180504A (Lien et al., GCN 22682) with the
Nordic Optical Telescope equipped with the AlFOSC camera. The field has
a bad visibility from La Palma, and observations were carried out at
large airmass (~2) and straddling twilight. The average seeing was 1.5".
Coincident with the UVOT-enhanced position reported by Evans (GCN
22683), we note the presence of a faint source, at a position (J2000;
0.5" error):
RA = 22:04:34.61
Dec = -14:39:30.0
We note that the automatically reported un-enhanced XRT position
(available from http://www.swift.ac.uk/xrt_positions/) is at the time of
writing significantly different from the one quoted in the GCN, and
would not include our afterglow candidate.
Photometry of the candidate against nearby stars from the Pan-STARRS
survey yields r = 22.5 +/- 0.3 (AB) at a mean time 2018 May 5.222 UT
(9.57 hr after the trigger)
Further observations are planned.
|
| GCN 22685 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22685 |
| Detection_method |
Swift-XRT Other |
| ra |
331.1442° |
| decl |
-14.6583° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22685
SUBJECT: GRB 180504A: Swift-XRT refined Analysis
DATE: 18/05/05 08:09:42 GMT
FROM: Phil Evans at U of Leicester
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte (PSU), J.A.
Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri
(INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 180504A (Lien et al. GCN
Circ. 22682), from 98 s to 30.5 ks after the BAT trigger. The data
comprise 163 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The best available XRT position (using the promptly downlinked
event data, the XRT-UVOT alignment and matching UVOT field sources to
the USNO-B1 catalogue) is RA, Dec = 331.1442, -14.6583 which is
equivalent to:
RA (J2000): 22 04 34.61
Dec(J2000): -14 39 30.0
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.7 (+nan, -nan).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.80 (+/-0.11). The
best-fitting absorption column is 6.9 (+3.2, -2.8) x 10^20 cm^-2, in
excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.86 (+0.25, -0.23)
and a best-fitting absorption column of 1.5 (+0.8, -0.7) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.7 x 10^-11 (4.6 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.5 (+0.8, -0.7) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 2.7 sigma
Photon index: 1.86 (+0.25, -0.23)
If the light curve continues to decay with a power-law decay index of
0.7, the count rate at T+24 hours will be 7.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x
10^-13 (3.4 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/00830822.
This circular is an official product of the Swift-XRT team.
|
| GCN 22686 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22686 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22686
SUBJECT: Correction to Swift-XRT light curve fit for GRB 180504A in GCN 22685
DATE: 18/05/05 08:20:13 GMT
FROM: Kim Page at U.of Leicester
K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
The fit results to the Swift-XRT light curve provided in GCN 22685 were
incomplete. The correct fit is as follows:
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha= 1.47 (+0.16, -0.17). At T+222 s the decay
steepens to an alpha of 2.81 (+0.20, -0.14) before breaking again at
T+1078 s to a final decay with index alpha=0.83 (+/- 0.13).
If the light curve continues to decay with a power-law decay index of 0.83
, the count rate at T+24 hours will be 2.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x 10^-13
(1.3 x 10^-13) erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
[GCN OPS NOTE(05may18): Per author's request, the GRB name
was added to the Subject-line.]
|
| GCN 22687 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22687 |
| Detection_method |
Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22687
SUBJECT: GRB 180504A: ePESSTO NTT NIR observations
DATE: 18/05/05 15:09:36 GMT
FROM: Paolo D'Avanzo at INAF-OAB
P. Clark (QUB), O. McBrien (QUB), D. Malesani (DAWN, DARK), P. D'Avanzo (INAF-OAB), E. Kankare (QUB),
M. T. Botticella (INAF Capodimonte), K. Maguire (QUB), M. Dennefeld (IAP, Paris), C. Inserra (Southampton),
S. J. Smartt (QUB), O. Yaron (Weizmann), D. R. Young (QUB), I. Manulis (Weizmann) report:
We observed the field of GRB 180504A (Lien et al., GCN Circ. 22682) under the extended Public ESO Spectroscopic
Survey for Transient Objects (ePESSTO; see Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org ). The observations
were performed on the ESO New Technology Telescope at La Silla with the SofI instrument in imaging mode starting from
2018-05-05 at 08:37:49 UT (i.e. about 12.9 hours from the burst) and consisted of 15 images obtained with the J filter,
each one lasting 90s.
The afterglow candidate reported by Malesani et al. (GCN Circ. 22684) is clearly detected. From preliminary photometry,
we estimate a magnitude of J ~ 21.3 (Vega, calibrated against the 2MASS catalogue).
|
| GCN 22690 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22690 |
| Detection_method |
Swift-BAT Det |
| ra |
331.1440° |
| decl |
-14.6650° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22690
SUBJECT: GRB 180504A: Swift-BAT refined analysis
DATE: 18/05/05 23:31:08 GMT
FROM: Hans Krimm at NASA-GSFC/NSF
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), 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), 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 180504A (trigger #830822)
(Lien, et al., GCN Circ. 22682). The BAT ground-calculated position is
RA, Dec = 331.144, -14.665 deg which is
RA(J2000) = 22h 04m 34.7s
Dec(J2000) = -14d 39' 53.6"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
The mask-weighted light curve shows a triangular shaped profile,
beginning at
~T-60 sec, peaking at ~T+20 sec, and decaying by T+80 sec.
T90 (15-350 keV) is 88.3 +- 44.4 sec (estimated error including
systematics).
The time-averaged spectrum from T-25.03 to T+113.85 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.50 +- 0.13. The fluence in the 15-150 keV band is 2.2 +- 0.2 x
10^-6erg/cm2.
The 1-sec peak photon flux measured from T+16.80 sec in the 15-150 keV band
is 0.8 +- 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/830822/BA/
|
| GCN 22691 table |
|---|
| GRB_name |
GRB180504A |
| GCN_number |
22691 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22691
SUBJECT: GRB 180504A: Swift/UVOT Upper Limits
DATE: 18/05/07 14:52:23 GMT
FROM: Jeffrey Gropp at PSU
J. D. Gropp (PSU), S. J. LaPorte (PSU), and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180504A
118 s after the BAT trigger (Lien et al., GCN Circ. 22682).
No optical afterglow consistent with the enhanced XRT position
(Evans GCN Circ. 22683)
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
b 5159 6793 116 >19.04
uvm2 5978 7606 136 >18.81
u_FC 302 6588 688 >19.53
u 705 1869 381 >19.47
v 631 651 136 >18.20
uvw1 6183 6383 136 >18.58
uvw2 5569 7204 136 >18.87
white_FC 143 6998 557 >20.67
white 582 1746 393 >20.46
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).
|