| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
4:16:03 UTC |
GCN_circulars,Swift Det |
| ra |
12.0386° |
Swift |
| decl |
-15.6305° |
Swift |
| pos_error |
5.57e-05° |
Swift |
| T90 |
40.9 s |
Swift |
| T90_start |
4:16:03 UTC |
Swift |
| fluence |
7.60e-07 erg/cm² |
Swift |
| redshift |
2.4870 |
GCN_circulars,Other |
| T100 |
40.9 s |
|
| GBM_located |
False |
|
| mjd |
58133.1778125 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB180115A |
| ra |
12.0750° |
| decl |
-15.6000° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB180115A |
| t_trigger |
4:16:03 UTC |
| ra |
12.0386° |
| decl |
-15.6305° |
| pos_error |
5.57e-05° |
| T90 |
40.9 s |
| fluence |
7.60e-07 erg/cm² |
| redshift |
2.4870 |
| GCN 22335 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22335 |
| Detection_method |
Swift Det |
| t_trigger |
4:16:03 UTC |
| ra |
12.0730° |
| decl |
-15.6080° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22335
SUBJECT: GRB 180115A: Swift detection of a burst with an optical counterpart.
DATE: 18/01/15 04:27:22 GMT
FROM: David Palmer at LANL
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (NASA/UMBC),
A. D'Ai (INAF-IASFPA), V. D'Elia (ASDC), A. Deich (PSU),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 04:16:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180115A (trigger=805318). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 12.073, -15.608 which is
RA(J2000) = 00h 48m 18s
Dec(J2000) = -15d 36' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is usual for an image trigger, the
immediately available light curve shows no obvious variation.
The XRT began observing the field at 04:18:14.7 UT, 131.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 12.03953, -15.62924 which
is equivalent to:
RA(J2000) = 00h 48m 09.49s
Dec(J2000) = -15d 37' 45.3"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 138 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 3.57e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 140 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 00:48:09.25 = 12.03856
DEC(J2000) = -15:37:49.8 = -15.63051
with a 90%-confidence error radius of about 0.75 arc sec. This position is 5.6
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.54 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02.
Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.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 22337 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22337 |
| Detection_method |
Swift-XRT Det |
| ra |
12.0388° |
| decl |
-15.6306° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22337
SUBJECT: GRB 180115A: Enhanced Swift-XRT position
DATE: 18/01/15 10:45:08 GMT
FROM: Phil Evans at U of Leicester
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 3943 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 180115A, 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 = 12.03876, -15.63065 which is equivalent
to:
RA (J2000): 00h 48m 9.30s
Dec (J2000): -15d 37' 50.3"
with an uncertainty of 1.7 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 22338 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22338 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22338
SUBJECT: GRB 180115A: Swift-XRT refined Analysis
DATE: 18/01/15 11:09:44 GMT
FROM: Phil Evans at U of Leicester
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), P.A. Evans (U.
Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), V.
D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), D.N.
Burrows (PSU) and J.K. Cannizzo report on behalf of the Swift-XRT team:
We have analysed 6.6 ks of XRT data for GRB 180115A (Cannizzo et al.
GCN Circ. 22335), from 137 s to 13.1 ks after the BAT trigger. The
data comprise 86 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. 22337).
The light curve can be modelled with an initial power-law decay with an
index of alpha=3.6 (+0.6, -0.5), followed by a break at T+269 s to an
alpha of 0.71 (+/-0.04).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.26 (+0.13, -0.12). The
best-fitting absorption column is consistent with the Galactic value
of 1.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.94 (+0.12, -0.11) and a best-fitting absorption
column of 3.6 (+2.4, -2.0) x 10^20 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.3 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 3.6 (+2.4, -2.0) x 10^20 cm^-2
Galactic foreground: 1.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.94 (+0.12, -0.11)
If the light curve continues to decay with a power-law decay index of
0.71, the count rate at T+24 hours will be 0.025 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x
10^-13 (9.0 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/00805318.
This circular is an official product of the Swift-XRT team.
|
| GCN 22340 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22340 |
| Detection_method |
MITSuME |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22340
SUBJECT: GRB 180115A: MITSuME Akeno optical upper limits
DATE: 18/01/15 11:42:54 GMT
FROM: Katsuhiro L. Murata at Nagoya U
K. L. Murata, R. Itoh,T. Yoshii, Y. Tachibana, S. Harita, K. Morita, T.
Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180115A (Cannizzo et al.,
GCN Circular #22335) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.
The observation started on 2018-01-15 09:25:40 UT. We did not find the
previously reported candidate afterglow (Cannizzo et al., GCN Circular
#22335) in all three bands.
We obtained following limits for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~5.16 10:06:44 4320 >19.8 >19.6 >19.0
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
|
| GCN 22345 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22345 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22345
SUBJECT: GRB 180115A: NOT detection of optical counterpart
DATE: 18/01/15 22:47:53 GMT
FROM: Zach Cano at U of Iceland
Z. Cano (HETH/IAA-CSIC), K. E. Heintz (Univ. Iceland & DARK/NBI), A. de
Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), I. Marquez & S. Cazzoli
(IAA-CSIC) report on behalf of a larger collaboration:
We observed the field of GRB 180115A (Cannizzo et al.; GCN Circ. 22335)
with the 2.5-m Nordic Optical Telescope equipped with ALFOSC, starting at
19:40:26 UT on 15 January 2017. We obtained 3x300 s in the r-band. In our
co-added image a faint, new object is detected in the enhanced XRT error
circle (Goad et al.; GCN Circ. 22337), with an apparent magnitude of r =
21.3 +- 0.1, at a mean post-explosion epoch of +15.53 hours. The
calibration was performed using local Pan-STARRS standards in the GRB
field. This apparent magnitude is not corrected for foreground extinction.
|
| GCN 22346 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22346 |
| Detection_method |
Other |
| redshift |
2.4870 |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22346
SUBJECT: GRB 180115A: Redshift from OSIRIS/GTC
DATE: 18/01/15 22:57:40 GMT
FROM: Antonio de Ugarte Postigo at IAA-CSIC
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), Z. Cano, L. Izzo,
C.C. Thoene, D.A. Kann (HETH/IAA-CSIC), N. Castro-Rodriguez
(Grantecan, IAC, ULL), D. Perez Valladares (Grantecan) report on
behalf of a larger collaboration:
We observed the afterglow of GRB 180115A (Cannizzo et al. GCN 22335,
Cano et al. GCN 22345) with OSIRIS at the 10.4m GTC telescope. The
observation consisted of 3x900s exposure with grism R1000B, covering
the range between 3700 and 7800 Angstrom and was performed under
bad seeing conditions.
The observation started at 20:32 UT (16.28 hr after the burst), and the
acquisition image shows the afterglow at r=21.2+/-0.2. The spectrum
shows a weak continuum over all the spectral range. The low signal to
noise ratio of the spectrum only allows us to detect a single broad spectral
feature that we identify as Lyman alpha at a redshift of 2.487.
|
| GCN 22348 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22348 |
| Detection_method |
Swift-BAT Det |
| ra |
12.0400° |
| decl |
-15.6320° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22348
SUBJECT: GRB 180115A: Swift-BAT refined analysis
DATE: 18/01/16 02:02:07 GMT
FROM: Amy Lien at GSFC
S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC),
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+446 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180115A (trigger #805318)
(Cannizzo et al., GCN Circ. 22335). The BAT ground-calculated position is
RA, Dec = 12.040, -15.632 deg which is
RA(J2000) = 00h 48m 09.6s
Dec(J2000) = -15d 37' 55.0"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~ T+25 s and ends at ~T+70 s. The main peak occurs at ~T+66 s.
T90 (15-350 keV) is 40.9 +- 3.0 sec (estimated error including systematics).
The time-averaged spectrum from T+26.49 to T+70.28 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.66 +- 0.22. The fluence in the 15-150 keV band is 7.6 +- 1.1 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+65.96 sec in the 15-150 keV band
is 0.6 +- 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/805318/BA/
|
| GCN 22357 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22357 |
| Detection_method |
Swift-UVOT Det |
| ra |
12.0386° |
| decl |
-15.6305° |
| redshift |
2.4870 |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22357
SUBJECT: GRB 180115A: Swift/UVOT Detection
DATE: 18/01/16 20:26:27 GMT
FROM: Frank Marshall at Swift/UVOT
F. E. Marshall (NASA/GSFC) and J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift/UVOT team:
Additional observations of the optical afterglow of GRB 180115A
discovered with Swift/UVOT (Cannizzo et al., GCN Circ. 22335)
reveal an initially brightening and then fading source.
The source is not detected in any of the UV filters, consistent
with the redshift of 2.487 reported by de Ugarte Postigo et al. (GCN Circ. 22346).
The preliminary UVOT position is:
RA (J2000) = 00:48:09.27 = 12.03862 (deg.)
Dec (J2000) = -15:37:49.9 = -15.63054 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
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 140 290 147 17.61 +/- 0.04
white 753 773 20 16.95 +/- 0.07
white 5663 5863 197 19.18 +/- 0.08
v 628 648 20 16.50 +/- 0.16
b 554 574 20 16.93 +/- 0.11
u 299 548 246 16.32 +/- 0.04
w1 1109 13068 1165 >20.7
m2 4743 12296 1279 >21.8
w2 5769 7329 318 >20.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
|
| GCN 22362 table |
|---|
| GRB_name |
GRB180115A |
| GCN_number |
22362 |
| Detection_method |
Swift-BAT Det |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 22362
SUBJECT: GRB 180115A: SEDM Observations
DATE: 18/01/18 20:21:52 GMT
FROM: Virginia Cunningham at U of MD
V. Cunningham, J. D. Neill, S. B. Cenko, and R. Walters report on
behalf of the SEDM team:
We obtained a spectrum of the optical afterglow of GRB181105A
(Cannizzo et al., GCN 22335; Cano et al., GCN 22345; de Ugarte
Postigo et al., GCN 22346; Marshall et al., GCN 22357) with the
Spectral Energy Distribution Machine (SEDM) on the 60 inch
telescope at Palomar Observatory. The SEDM is a low resolution
(R ~ 100) integral field unit spectrometer with a multi-band (ugri)
“rainbow†camera imager (see Blagorodnova et al., 2017,
astro-ph/1710.02917).
Observations began at 4:30 UTC on January 15 (14 minutes after
the Swift BAT trigger) and covered the wavelength range from
3800-9200 A with an exposure time of 2700 s. Continuum emission
is clearly seen at wavelengths redder than 4500 A and is well fit by
a relatively steep power-law spectrum with index alpha = 1.93
(f_nu ~ nu^-alpha). No obvious emission or absorption features are
clearly detected in the spectrum; due to the low SNR at wavelengths
shorter than 4500 A we cannot confirm the detection of Ly-alpha at
z = 2.487 reported by de Ugarte Postigo et al. (GCN 22346).
[GCN OPS NOTE(07sep19): Per author's request, in the last paragraph
the "alpha = 1.93" was changed to "alpha = 0.93".]
|