- GCN Circular #5076
D. Palmer, J. Cummings, M. Stamatikos, C. Markwardt, T. Sakamoto
At 06:36:01 UT Swift-BAT triggered on GRB 060505 (Trigger #208654).
The onboard imaging detected a 6.4 sigma excess.
This is below our (6.5 sigma) threshold for ground notification
and automatic slew. Subsequent ground analysis imaged a different
selection of the data and found a convincing 8.5 sigma excess at
(RA, Dec) = 331.765, -27.819 {22h 07m 04s, -27d 49' 09s} (J2000)
The light curve shows a weak burst, ~1500 cts/sec (15-350 keV) 1 sec
after the trigger. T90 is ~4 seconds.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Fri 05 May 06 20:55:04 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 208654, Seg_Num: 11
GRB_RA: 331.765d {+22h 07m 04s} (J2000),
331.855d {+22h 07m 25s} (current),
331.054d {+22h 04m 13s} (1950)
GRB_DEC: -27.819d {-27d 49' 08"} (J2000),
-27.788d {-27d 47' 16"} (current),
-28.064d {-28d 03' 48"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 4000 [cnts] Image_Peak=200 [image_cnts]
TRIGGER_DUR: 2.048 [sec]
TRIGGER_INDEX: 473 E_range: 15-25 keV
BKG_INTEN: 184025 [cnts]
BKG_TIME: 23728.00 SOD {06:35:28.00} UT
BKG_DUR: 24 [sec]
GRB_DATE: 13860 TJD; 125 DOY; 06/05/05
GRB_TIME: 23761.02 SOD {06:36:01.02} UT
GRB_PHI: 22.13 [deg]
GRB_THETA: 49.71 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 33.00 [sigma]
IMAGE_SIGNIF: 8.50 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +0 +0 +0 +0 +0 +0
SUN_POSTN: 42.75d {+02h 51m 00s} +16.40d {+16d 23' 56"}
SUN_DIST: 81.60 [deg] Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN: 145.98d {+09h 43m 56s} +17.30d {+17d 17' 59"}
MOON_DIST: 168.20 [deg]
MOON_ILLUM: 56 [%]
GAL_COORDS: 22.08,-53.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 323.84,-15.17 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 0.00,0.00 [deg].
COMMENTS: This Notice was ground-reprocessed from flight-data.
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: On-board analysis found a 6.4 sigma source
COMMENTS: Ground based analysis of downloaded data over
COMMENTS: a longer time interval found an 8.5 sigma GRB
COMMENTS: This hand-generated notice is at T+14 hours.
- red DSS finding chart
ps-file
- GCN Circular #5078
M.L. Conciatore, M. Capalbi, L. Vetere (ASDC), D. Palmer (LANL),
D. Burrows (PSU) report on behalf of the Swift/XRT team:
The Swift XRT began observing GRB 060505 field (trigger #208654,
Palmer et al., GCN 5076) at 20:58:25 UT, 14.37 h after the BAT trigger.
From the analysis of the first 4 ks data set we find a faint source at
the following coordinates:
RA(J2000) = 22h 07m 03.2s
Dec(J2000) = -27d 48' 57"
with an estimated uncertainty of 5 arcseconds (90% containment). This
position lies 13.9 arcseconds from the center of the BAT error circle
reported in GCN 5076.
This source is 6.7 arcsec from the USNO star 0621-1164653 and 4.1
arcsec from the 2df galaxy S173Z112.
Due to the small number of counts, we are unable to determine whether
the source is decaying at this time. Observations are continuing and
further analysis regarding the fading nature of this source will be
issued as the data becomes available.
This circular is an official product of the Swift XRT Team.
- GCN Circular #5081
M.L. Conciatore, M. Capalbi, L. Vetere (ASDC), L.A. Antonelli (INAF/OAR),
D. Palmer (LANL), D. Burrows (PSU) report on behalf of the Swift/XRT
team:
We analysed the first 8 ks XRT data from GRB 060505. We found two
detections whithin the BAT error circle (GCN 5076). The first source
already reported in GCN 5078 shows a constant flux of (1.1 +/- 0.1)e-2
counts/s and it is unlikely to be associated with the afterglow of GRB
060505. We also note that the 2df galaxy S173Z112 lays within the XRT
error circle (GCN 5078).
A very faint second source is located at:
RA(J2000) = 22h 07m 4.5s,
Dec(J2000) =-27d 49m 57.8s
with an uncertainty of 4.7 arcsec (90% containment). This position lies
63.2 arcseconds from the center of the BAT error circle reported in
GCN 5076. Due to the small number of counts (15 counts) we are unable
to determine whether the source is the possible afterglow candidate of
GRB 060505.
We note that the positions of both sources are also consistent with a
previously known ROSAT source (1WGA J2207.0-2749) error box (50 arcsec).
This Circular is an official product of the Swift XRT Team.
- GCN Circular #5082
P J. Brown (Penn State) & D. Palmer (LANL)
on behalf of the Swift/UVOT team.
The Swift/UVOT began observing the field of GRB060505
(BAT Trigger=208654, Palmer et. al, GCN 5076) at
2006-05-05 20:58:30 UT, 14.37 hours after the BAT trigger.
The galaxy at the position of the first XRT source
(Conciatore et al GCN 5078) is detected in all 6 filters
but does not show significant variation, consistent with
Conciatore et al (GCN 5081).
No source is detected at the position of the second XRT
source (Conciatore et al GCN 5081) in coadded images with
any of the filters. The following 5-sigma magnitude
upper limits are not corrected for Galactic extinction.
Filter T_range(h) T_exp(s) 5sigmaUpperLimit(mag)
V 14.85-19.73 835 19.1
B 14.56-19.44 835 20.2
U 14.49-19.38 835 19.9
UVW1 14.37-19.32 1666 19.8
UVM2 14.92-19.85 1987 20.1
UVW2 14.62-19.67 3388 21.0
Where T_range is time post-trigger in hours, and T_exp
is the exposure time of the summed image in seconds.
- GCN Circular #5089
J. Haislip, M. Nysewander, D. Reichart, A. LaCluyze, J. A. Crain, K.
Ivarsen, A. Foster, C. MacLeod, J. Kirschbrown, A. Trotter, and J.
Carpenter report on behalf of the UNC team of the FUN GRB Collaboration:
Skynet observed the localization of GRB 060505 (Palmer et al., GCN 5076)
with three of the 16-inch PROMPT telescopes at CTIO beginning 23.2 hours
after the burst in Ug'r'i'z'. Two of these telescopes reobserved the field
in i'z' beginning 47.2 hours after the burst.
No new source is found to z' > 20.6 mag (3 sigma) at 25.5 hours after the
burst.
PROMPT is currently being built and commissioned.
- GCN Circular #5114
M.L. Conciatore, M. Capalbi, L. Vetere (ASDC), D. Palmer (LANL),
D. Burrows (PSU) report on behalf of the Swift/XRT team:
The Swift X-Ray Telescope observed the field of GRB 060505 (GCN 5076)
for a second time on 2006-05-10 from 00:43:58 UT for a total
exposure of 11.7 ks.
The source identified in the first observation (GCN 5078) located at:
RA(J2000) = 22h 07m 03.2s
Dec(J2000) = -27d 48' 57
has faded from (1.1 +/- 0.1)e-2 counts/s to
(8.6 +/- 4.0)e-4 cts/s.
The other source reported in GCN 5081, located at:
RA(J2000) = 22h 07m 4.5s,
Dec(J2000) =-27d 49m 57.8s
shows a constant behavior of the light curve, with a count rate of
about 2e-2 cts/s.
We conclude that the first source is the likely X-ray afterglow
of GRB 060505.
This Circular is an official product of the Swift XRT Team.
- GCN Circular #5115
M.L. Conciatore (ASDC) report on behalf of the Swift/XRT team:
In GCN 5114, we incorrectly reported that count rate of the second
source (the constant one) was 2.e-2 cts/s. The correct value is 2.e-3
cts/s.
Please, find below the corrected GCN text.
========================================================================
M.L. Conciatore, M. Capalbi, L. Vetere (ASDC), D. Palmer (LANL),
D. Burrows (PSU) report on behalf of the Swift/XRT team:
The Swift X-Ray Telescope observed the field of GRB 060505 (GCN 5076)
for a second time on 2006-05-10 from 00:43:58 UT for a total exposure
of 11.7 ks.
The source identified in the first observation (GCN 5078) located at:
RA(J2000) = 22h 07m 03.2s
Dec(J2000) = -27d 48' 57
has faded from (1.1 +/- 0.1)e-2 counts/s to
(8.6 +/- 4.0)e-4 cts/s.
The other source reported in GCN 5081, located at:
RA(J2000) = 22h 07m 4.5s,
Dec(J2000) =-27d 49m 57.8s
shows a constant behavior of the light curve,
with a count rate ofabout 2e-3 cts/s.
We conclude that the first source is the likely X-ray afterglow
of GRB 060505.
This Circular is an official product of the Swift XRT Team.
- GCN Circular #5123
E. O. Ofek, S. B. Cenko, A. Gal-Yam (Caltech), B. Peterson, B. P.
Schmidt, (ANU), D. B. Fox (Penn State), and P. A. Price (IfA, Hawaii)
report on behalf of a larger collaboration:
We have imaged the region of the 4s-duration GRB060505 (GCNs 5076; 5078;
5114; 5115) with the GMOS instrument on the Gemini South Telescope, in g'
and r'-bands, on 2006 May 6.4 and on 2006 May 12.3.
Inspection of single g' and r'-band images from each night reveals the
presence of a variable source 4."3 from the z=0.089 galaxy 2dFGRS
S173Z112 (7kpc in projection). The afterglow coordinates are:
22:07:03.44 -27:48:51.9 (J2000.0)
relative to the USNO-A2.0 catalog.
The OT is found 6" from the nominal XRT coordinates
(which have 4."7 uncertainty, 90% confidence).
On 2006 May 6.40, the g'-band magnitude of the proposed afterglow was
g~21.5,
and on 2006 May 12.31 it was g'~22 (Compared to USNO-A2.0).
We further inspected the publicly available 2dF spectra
of the z=0.089 galaxy 2dFGRS S173Z112, found within the XRT error circle
of GRB 060505 (GCN 5078).
The spectra shows prominent emission lines of Halpha, Hbeta, OI, OII, OIII
and SII. In absorption we detect the G-band and the CaII H line (but not
the K line). The spectrum suggests this is a late type galaxy.
- GCN Circular #5142
D. Hullinger (BYU-Idaho), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/JSPS/USRA), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), on behalf of the Swift-BAT team:
Using the data set from T-2 to T+8 sec, we report further analysis
of GRB 060505 (Palmer et al. GCN 5076). The refined ground-analysis
position is RA, Dec 331.776d, -27.825d (22h 07m 06.3s, -27d 49' 31")
+- 2.1 arcmin (J2000, estimated uncertainty, 90% containment). This
position is 0.6 arcmin from the XRT refined position reported by
Conciatore et al. in GCN 5081. The partial coding was 11%. As noted
earlier, this was a ground-discovered burst that did not trigger the
BAT instrument. Thus we have only a limited set of full-resolution
data.
The mask-weighted light curve shows a single rounded peak. T90 is
4 +- 1 sec (15-350 keV, estimated error including systematics).
The BAT counting rates give no indication of extended emission.
However, Swift was approaching the SAA and BAT entered SAA mode
with even more limited data collection at T+60, so constraints on
emission are poor.
The time-averaged spectrum is well fit by a simple powerlaw with
index 1.3 +- 0.3. The energy fluence in the 15-150 keV band is
6.2 +- 1.1 x 10^-7 ergs/cm2. The 1-second peak flux, also in the
15-150 keV band, from T+2 sec is 1.9 +- 0.3 ph/cm2/s. All the
quoted errors are at the 90% confidence level.
- GCN Circular #5161
Christina C. Thoene, Johan P.U. Fynbo, Jesper Sollerman, Brian L. Jensen,
Jens Hjorth (Dark Cosmology Centre), Pall Jakobsson (Univ. of Hertfortshire),
Sylvio Klose (TLS Tautenburg) report on behalf of a larger collaboration:
We observed the OT position of GRB060505 (GCN 5123), with FORS2/VLT on May
23.28. Comparison with our FORS1/VLT images from May 5.41 shows that the
source has faded from R=21.3 on May 5.41 to R>23 on May 23.28.
At the position of the OT, we detect a bright, star-forming region in the
spiral arm of the possible host galaxy 2dFGRS S173Z112 with redshift
z=0.089 (GCN 5123). Spectroscopy with VLT/FORS2 confirms that this region
is part of the host galaxy. Therefore, it is possible that the source
reported in GCN 5123 for images taken on May 12th, might actually be the
underlying star-forming region.
The observations put a strong limit on the presence of an underlying SN
similar to SN 1998bw at redshift 0.089, which we would expect to have a
magnitude of R=18.4 at the time of our 2nd observation. Therefore, either
there is no associated SN, the SN is about 4 magnitudes fainter than SN
1998bw, it is strongly extinguished, or GRB060505 is not at z=0.089. The
strengths of the Balmer lines and the fact that the host galaxy is seen
close to face on argue against strong dust extinction.
We thank the Paranal staff, in particular Claudio Melo and Rachel Gilmour,
for excellent support.
- astro-ph/0703192 from 8 Mar 2007
Ofek: GRB 060505: A possible short-duration gamma-ray burst in a star forming region at redshift of 0.09
On 2006 May 5, a four second duration, low energy, ~10^49 erg, Gamma-Ray
Burst (GRB) was observed, spatially associated with a z=0.0894 galaxy. Here, we
report the discovery of the GRB optical afterglow and observations of its
environment using Gemini-south, Hubble Space Telescope (HST), Chandra, Swift
and the Very Large Array. The optical afterglow of this GRB is spatially
associated with a prominent star forming region in the Sc-type galaxy 2dFGRS
S173Z112. Its proximity to a star forming region suggests that the progenitor
delay time, from birth to explosion, is smaller than about 10 Myr. Our HST deep
imaging rules out the presence of a supernova brighter than an absolute
magnitude of about -11 (or -12.6 in case of ``maximal'' extinction) at about
two weeks after the burst, and limits the ejected mass of radioactive Nickel 56
to be less than about 2x10^-4 solar mass (assuming no extinction). Although it
was suggested that GRB 060505 may belong to a new class of long-duration GRBs
with no supernova, we argue that the simplest interpretation is that the
physical mechanism responsible for this burst is the same as for short-duration
GRBs.
- astro-ph/0703407 from
Thoene: Spatially resolved properties of the GRB 060505 host: implications for the nature of the progenitor
GRB 060505 was the first well-observed nearby long-duration GRB that had no
associated supernova. Here we present spatially resolved spectra of the host
galaxy of GRB 060505, an Sbc spiral, at redshift z=0.0889. The GRB occurred
inside a star-forming region in the northern spiral arm at 6.5 kpc from the
center. From the position of the emission lines, we determine a maximum
rotational velocity for the galaxy of v ~ 212 km/s corresponding to a mass of
1.3x10^11 M_solar within 24 kpc. The Halpha equivalent width at the GRB site
gives a very young age of <~ 7 Myr. By fitting single-age spectral synthesis
models to the stellar continuum, we derive ages for the dominant stellar
populations in different parts of the galaxy resulting in ~ 800 Myr for the
bulge an only ~ 47 Myr for the GRB site. The metallicity derived from the R_23
parameter is lowest at the GRB site with 0.14 Z_solar but roughly solar in the
rest of the galaxy. The extinction in the galaxy is overall low with A_V < 0.40
mag in the bulge and A_V < 0.09 mag at the GRB site. Using the 2dF galaxy
redshift survey we can locate the host galaxy in its large scale (~Mpc)
environment. The galaxy lies in the foreground of a filamentary overdensity
extending south west from the galaxy cluster Abell 3837 at z=0.0896. The
properties of the GRB site are similar to those found for other long-duration
GRBs with high specific star formation rate and low metallicity, which is an
indication that GRB 060505 originated from a young massive star that died
without making a supernova.
- 0706.0674from 5 Jun 2007
Thoene: The spatially resolved host of GRB 060505 and implications for the nature of the progenitor
Abstract: We present a study of the host galaxy of the Gamma-Ray Burst (GRB) of May 5
2006 (GRB 060505). The host is spatially resolved in both imaging data and in a
long slit spectrum including the GRB site. We find the galaxy to be a Sbc
spiral, which is unusual for a long GRB host galaxy. The site of the GRB is
considerably different from the rest of the galaxy with intense star formation,
low metallicity and a young age. This suggest a massive stellar progenitor
rather than a merger of compact objects which has been suggested based on the
the relatively short duration of T_90=4s for the prompt emission.
- 0708.0833from 6 Aug 2007
Levesque: The Host Galaxy of GRB 060505: Host ISM Properties
Abstract: We investigate the ISM environment of GRB 060505. Using optical emission-line
diagnostic ratios, we compare the ISM properties of the GRB 060505 host region
with the hosts of unambiguous long- and short-duration GRBs. We show that the
metallicity, ionization state, and star formation rate of the GRB 060505
environment are more consistent with short-duration GRBs than with
long-duration GRBs. We compare the metallicity and star formation rates of the
GRB 060505 region with four other star-forming regions within the GRB 060505
host galaxy. We find no significant change in metallicity or star formation
rate between the GRB 060505 region and the other four host regions. Our results
are consistent with a compact-object-merger progenitor for GRB 060505.
- 0803.1919from 13 Mar 2008
McBreen: The Spectral Lag of GRB060505: A Likely Member of the Long Duration Class
Abstract: Two long gamma-ray bursts, GRB 060505 and GRB 060614, occurred in nearby
galaxies at redshifts of 0.089 and 0.125 respectively. Due to their proximity
and durations, deep follow-up campaigns to search for supernovae (SNe) were
initiated. However none were found in either case, to limits more than two
orders of magnitude fainter than the prototypical GRB-associated SN, 1998bw. It
was suggested that the bursts, in spite of their durations (4 and 102 s),
belonged to the population of short GRBs which has been shown to be unrelated
to SNe. In the case of GRB 060614 this argument was based on a number of
indicators, including the negligible spectral lag, which is consistent with
that of short bursts. GRB 060505 has a shorter duration, but no spectral lag
was measured. We present the spectral lag measurements of GRB 060505 using
Suzakus Wide Area Monitor and the Swift Burst Alert Telescope. We find that the
lag is 0.36+/- 0.05 s, inconsistent with the lags of short bursts and
consistent with the properties of long bursts and SN-GRBs. These results
support the association of GRB 060505 with other low-luminosity GRBs also found
in star-forming galaxies and indicates that at least some massive stars may die
without bright SNe.
- 1206.4151 from 20 Jun 12
E. J. Howell et al.: A redshift -- observation-time relation for gamma-ray bursts: evidence of a distinct sub-luminous population
We show how the redshift and peak-flux distributions of gamma-ray bursts (GRBs) have an observation time dependence that can be used to
discriminate between different burst populations. We demonstrate how observation time relations can be derived from the standard integral
distributions and that they can differentiate between GRB populations detected by both the BATSE and \emph{Swift} satellites. Using
\emph{Swift} data we show that a redshift--observation-time relation (log\,$Z$\,--\,log\,$T$) is consistent with both a
peak-flux\,--\,observation time relation (log\,$P$\,--\,log\,$T$) and a standard log\,$N$\,--\,log\,$P$ brightness distribution. As the method
depends only on rarer small-$z$ events, it is invariant to high-$z$ selection effects. We use the log\,$Z$\,--\,log\,$T$ relation to show that
sub-luminous GRBs are a distinct population occurring at a higher rate of order $150^{+180}_{-90} \mathrm{Gpc}^{-3}\mathrm{yr}^{-1}$. Our
analysis suggests that GRB 060505 -- a relatively nearby GRB observed without any associated supernova -- is consistent with a sub-luminous
population of bursts. Finally, we suggest that our relations can be used as a consistency test for some of the proposed GRB spectral energy
correlations.
- 1601.00180 from 5 Jan 16
Xiang Li et al.: Long-short GRBs within the horizon of the advanced LIGO/VIRGO network and Time lag between compact object coalescence and GRB onset
Short duration GRBs (SGRBs) are widely believed to be powered by the mergers of compact binaries, like binary neutron stars or possibly neutron
star-black hole binaries. Though the prospect of detecting SGRBs with gravitational wave (GW) signals by the advanced LIGO/VIRGO network is
promising, no known SGRB has been found within the expected advanced LIGO/VIRGO sensitivity range. We argue, however, that the two long-short
GRBs (GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors. In the upcoming era of GW astronomy, the merger origin of
some long-short GRBs, as favored by the macronova signature displayed in GRB 060614, can be unambiguously tested. The model-dependent time-lags
between the merger and the onset of the prompt emission of GRB are estimated. The comparison of such time-lags between model prediction to the
real data expected in the era of the GW astronomy would be helpful in revealing the physical processes taking place at the central engine
(including the launch of the relativistic outflow, the emergence of the outflow from the dense material ejected during the merger and the
radiation of gamma-rays). The achievable accuracy of measuring the speed of GW in the advanced LIGO/VIRGO era is also examined.
- 1603.07869 from 28 Mar 16
Zhi-Ping Jin et al.: The 050709 macronova and the GRB/macronova connection
We reanalyzed the publicly-available optical/near-infrared afterglow observations of GRB 050709, the first short GRB from which an optical
afterglow was detected. The $I$-band/F814W-band light curve is significantly shallower than the $R$-band light curve. This additional
low-luminosity soft component can be a signature of a Li-Paczy\'{n}ski macronova (also known as kilonova) arising from $\sim 0.05~M_\odot$
r-process material launched by a compact binary merger. As macronovae are relatively weak and soft they can be identified only within the
afterglows of relatively nearby ($z<0.4$) bursts that have sufficient near-infrared/optical data. There are five such events: GRBs 050709,
060505, 060614, 061201 and 130603B. However, the redshift of 061201 is unclear and there is doubt concerning the origin of GRB 060505.
Remarkably, evidence for a macronova signature is found in the afterglow of each one of the remaining three events. This demonstrates that
macronovae are ubiquitous. The significant mass ejection supports the suggestion that these events are significant and possible main sites of
heavy r-process nucleosynthesis. The identification of two of the three macronova candidates in the $I$-band implies a more promising detection
prospect for the ground-based survey.
Previous IAU Circulars 