Gamma-ray Burst 140623A
(All information courtesy of the instrument teams.)
Previous IAU Circulars
Results of Observations
- GCN Circular #16444
V. B. Bhalerao (IUCAA), L. P. Singer (Caltech), M. M. Kasliwal
(Carnegie Observatories/Princeton), S. B. Cenko (NASA/GSFC), A. Horesh
(Weizmann Institute) and D. A. Perley (Caltech) report on behalf of
the intermediate Palomar Transient Factory (iPTF) collaboration:
Fermi GBM reported trigger 425193729 at 2014-06-23 05:22:06.600 UT.
Starting 2014-06-23 05:33:07.776 UT (JD 2456831.73134, 11 min after
trigger), we began our search for optical counterparts using the
Palomar 48-inch Oschin telescope (P48). Based on the automated Fermi
ground localization, we selected 10 fields covering an area of 74
The final Fermi localization, available 2.6 hours after the trigger,
differed in position by 13.4 deg. Based on the final localization and
an empirical description of the systematic errors of the GBM
localization (Paciesas et al. 2012,
http://dx.doi.org/10.1088/0067-0049/199/1/18), we estimate a 4% chance
that these fields contain the true location of the source.
Sifting through candidate transient sources using image subtraction
and standard intermediate Palomar Transient Factory vetting
procedures, we detected several optical transients. The fastest fading
transient was iPTF14cyb, at the coordinates:
RA(J2000) = 15h 01m 53.42s (225.472574 deg)
Dec(J2000) = +81d 11' 29.1" (+81.191410 deg)
We note that the position of 1PTF 14cyb is consistent with both the
iniital ground and final localizations.
Measured R magnitudes of iPTF14cyb are
These are consistent with a power-law decay with index -0.93 +- 0.17.
We observed iPTF14cyb with the Gemini Multi-Object Spectrograph
mounted on the 8m Gemini North telescope beginning at 08:10 UT on 2014
June 23 (~ 2.8 hr after the GBM trigger). Two 900 s spectra were
obtained, covering the wavelength range from 4000-9300 A.
Super-imposed on a relatively flat continuum, we detect a number of
strong absorption features, including Mg II, Fe II, Al II, Si II, Al
III, C I, and C IV, at a common redshift of z = 1.92. The lack of
Ly-alpha absorption in the spectrum suggests that this is the redshift
of the Fermi GBM GRB. In addition, we detect strong absorption
features (Mg II, Fe II) from an intervening system at a redshift of z
http://www.its.caltech.edu/~lsinger/iptf/Fermi425193729.pdf shows the
locations of the afterglow and the 10 P48 fields in relation to the
Fermi GBM 1- and 2-sigma statistical+systematic contours.
We have triggered follow-up observations with Swift, EVLA and CARMA.
We encourage follow-up observations to confirm the nature of the
We thank GoGo Inflight Wifi for internet at 10,000 feet.
- GCN Circular #16450
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 05:22:06.60 UT on 23 June 2014, the Fermi Gamma-Ray Burst Monitor
and located GRB 140623A (trigger 425193729 / 140623224), which was observed
by the intermediate Palomar Transient Factory beginning 11 minutes after
trigger time, and was reported in GCN 16425 (Bhalerao et al. 2014) as
The on-ground calculated location, using the GBM trigger
data, is RA = 202.8, DEC = 75.8 (J2000 degrees,
equivalent to 13h 31m, 75d 48'), with an uncertainty
of 5.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 32 degrees.
The GBM light curve shows a multiple-peak structure
with a duration (T90) of about 110 s (50-300 keV).
The time-averaged spectrum from T0-49.2 s to T0+73.7 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.46 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 350(+220/-100) keV
The event fluence (10-1000 keV) in this time interval is
(6.8 +/- 0.6)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0-3.65 s in the 10-1000 keV band
is 1.9 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #16451
V. D'Elia (ASDC), F. E. Marshall (NASA/GSFC), L. Izzo (URoma/ICRA) &
D. Malesani (DARK/NBI) report on behalf of the Swift team:
Following the report of a potential optical afterglow iPTF14cyb
(Bhalerao et al., GCN Circ. 16442) to the Fermi/GBM-detected burst GRB
140623A (von Kienlin, GCN Circ. 16450), Swift began a follow-up
observation of the iPTF field.
We have analyzed all the 3.0 ks of XRT data for GRB 140623A, from
38.7 ks to 49.6 ks after the Fermi/GBM trigger. The data are entirely
in Photon Counting (PC) mode. An X-ray source is detected at a
position consistent with the candidate optical afterglow (Bhalerao et
al., GCN Circ. 16442) within the Fermi/GBM error circle.
Using 1153 s of PC mode data and 1 UVOT images, we find an enhanced
XRT position (using the XRT-UVOT alignment and matching UVOT field
sources to the USNO-B1 catalogue): RA, Dec = 225.47927, +81.19049
which is equivalent to:
RA (J2000): 15h 01m 55.02s
Dec(J2000): +81d 11' 25.7"
with an uncertainty of 5.8 arcsec (radius, 90% confidence). This
position is 5.0 arcsec from the the optical counterpart iPTF14cyb, and
consistent with it. We cannot determine at the present time whether
the source is fading.
The results of the XRT-team automatic analysis are available at
The Swift/UVOT began settled observations of the field of GRB 140423A
38708 s after the GBM trigger. No optical afterglow consistent with
the optical position (Bhalerao et al. GCN Circ. 16442) 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,
Filter T_start(s) T_stop(s) Exp(s) Mag
u 38708 44173 925 >22.0
white 38926 44863 851 >21.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.037 in the direction of the burst
(Schlegel et al. 1998).
This circular is an official product of the Swift team.
- GCN Circular #16464
V. D'Elia (ASDC), L. Izzo (URoma/ICRA) report on behalf of the Swift-XRT team:
We report further Swift-XRT observations of GRB 140623A (A. von
Kienlin, GCN Circ 16450; Bhalerao et al., GCN Circ. 16442). A new
exposure of 5 ks has been secured 285 ks after the Fermi/GBM
detection. The X-ray counterpart detected by D'Elia et al. (GCN Circ.
16451) is no longer present down to a three sigma upper limit of
We thus conclude that the source reported in D'Elia et al. (GCN Circ.
16451) is the X-ray afterglow of GRB 140623A.
This circular is an official product of the Swift-XRT team.
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Jochen Greiner, last update: 29-Jun-2014