- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Jun 07 02:40:00 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 282066, Seg_Num: 0
GRB_RA: 121.385d {+08h 05m 32s} (J2000),
121.507d {+08h 06m 02s} (current),
120.562d {+08h 02m 15s} (1950)
GRB_DEC: +37.266d {+37d 15' 56"} (J2000),
+37.244d {+37d 14' 38"} (current),
+37.409d {+37d 24' 32"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 0 [cnts] Image_Peak=1928 [image_cnts]
TRIGGER_DUR: 64.000 [sec]
TRIGGER_INDEX: 20000 E_range: 15-50 keV
BKG_INTEN: 0 [cnts]
BKG_TIME: 0.00 SOD {00:00:00.00} UT
BKG_DUR: 0 [sec]
GRB_DATE: 14263 TJD; 163 DOY; 07/06/12
GRB_TIME: 9525.98 SOD {02:38:45.98} UT
GRB_PHI: -108.52 [deg]
GRB_THETA: 39.94 [deg]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 14.22 [sigma]
MERIT_PARAMS: +1 +0 +0 +6 +1 +3 -100 +0 -78 +1
SUN_POSTN: 79.97d {+05h 19m 54s} +23.12d {+23d 07' 04"}
SUN_DIST: 38.22 [deg] Sun_angle= -2.8 [hr] (East of Sun)
MOON_POSTN: 35.44d {+02h 21m 47s} +18.71d {+18d 42' 19"}
MOON_DIST: 75.77 [deg]
MOON_ILLUM: 13 [%]
GAL_COORDS: 183.62, 30.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 115.62, 16.58 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is an image trigger. (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)
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 = 290.32,5.28 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 12 Jun 07 02:42:38 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 282066, Seg_Num: 0
GRB_RA: 121.385d {+08h 05m 32s} (J2000),
121.507d {+08h 06m 02s} (current),
120.562d {+08h 02m 15s} (1950)
GRB_DEC: +37.266d {+37d 15' 56"} (J2000),
+37.244d {+37d 14' 38"} (current),
+37.409d {+37d 24' 32"} (1950)
GRB_DATE: 14263 TJD; 163 DOY; 07/06/12
GRB_TIME: 9525.98 SOD {02:38:45.98} UT
TRIGGER_INDEX: 20000
GRB_PHI: -108.52 [deg]
GRB_THETA: 39.94 [deg]
DELTA_TIME: 0.00 [sec]
TRIGGER_DUR: 64.000 [sec]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 14.22 [sigma]
LC_URL: sw00282066000msb.lc
SUN_POSTN: 79.98d {+05h 19m 54s} +23.12d {+23d 07' 04"}
SUN_DIST: 38.21 [deg] Sun_angle= -2.8 [hr] (East of Sun)
MOON_POSTN: 35.47d {+02h 21m 53s} +18.72d {+18d 42' 55"}
MOON_DIST: 75.74 [deg]
MOON_ILLUM: 13 [%]
GAL_COORDS: 183.62, 30.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 115.62, 16.58 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is an image 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 = 290.32,5.28 [deg].
- GCN Circular #6509
D. Grupe (PSU), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU),
W. B. Landsman (NASA/GSFC), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), D. C. Morris (PSU), D. M. Palmer (LANL),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:
At 02:38:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070612 (trigger=282066).
The BAT on-board calculated location is
RA, Dec 121.385, +37.266 which is
RA(J2000) = 08h 05m 32s
Dec(J2000) = +37d 15' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single hard-
spectrum FRED peak with a duration of about 30 sec. The peak count
rate was ~1100 counts/sec (15-350 keV), at ~-1 sec after the trigger.
Because of a Sun constraint, the spacecraft did not slew promptly
to the BAT position, and so there are no XRT or UVOT data
products to analyze. XRT and UVOT will not be able to observe this
target until the end of August.
- GCN Circular #6510
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg
(NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann
(APO), Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel
E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB070612
prior to the burst. As these data should be useful as a pre-burst
comparison and for calibrating photometry, we are supplying the images
and photometry measurements for this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and
3 files of photometry and astrometry, are being placed at
http://mizar.as.arizona.edu/~grb/public/GRB070612
We supply FITS images in each of the 5 SDSS bands of a 8'x8' region
centered on the GRB position (ra=121.385 (08:05:32.4), dec=37.2660
(37:15:57.6); GCN 6509), as well as 3 gri color-composite JPGs (with
different stretches). The units in the FITS images are nanomaggies
per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie is a
flux-density unit equal to 10^-9 of a magnitude 0 source or, to the
extent that SDSS is an AB system, 3.631e-6 Jy. The FITS images have
WCS astrometric information.
In the file GRB070612_sdss.calstar.dat, we report photometry and
astrometry of 396 bright stars (r<20.5) within 15' of the burst location.
The magnitudes presented in this file are asinh magnitudes as are standard
in the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars
are not well-detected in the u-band; use the errors and object flags to
monitor data quality.
In the files GRB070612_sdss.objects_flux.dat and
GRB070612_sdss.objects_magnitudes.dat, we report photometry of 1013
objects detected within 6' of the GRB position. We have removed saturated
objects and objects with model magnitudes fainter than 23.0 in the r-band.
The fluxes listed in GRB070612_sdss.objects_flux.dat are in nanomaggies
while the magnitudes listed in GRB070612_sdss.objects_magnitudes.dat
are asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning that
they are very close to AB zeropoints and magnitudes are quoted in
asinh magnitudes. Photometric zeropoints are known to about 2% rms.
None of the photometry is corrected for dust extinction. The Schlegel,
Finkbeiner, and Davis (1998) predictions for this region are A_U=0.281
mag, A_g=0.207 mag, A_r = 0.150 mag, A_i=0.114 mag, and A_z=0.081 mag.
The file GRB070612_sdss.spectro.dat contains a list of the 2 objects with
SDSS spectroscopy within 6 arcminutes of the GRB position. In addition
to the redshift and 1-sigma error for each object, this file also lists
the object spectroscopic classification.
SDSS astrometry is generally better than 0.1 arcsecond per coordinate.
Users requiring high precision astrometry should take note that the SDSS
astrometric system can differ from other systems such as those used in
other notices; we have not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases can be
found in our initial data release paper (Cool et al. 2006, PASP 118, 733).
See the SDSS DR4 documentation for more details: http://www.sdss.org/dr5
These data have been reduced using a slightly different pipeline than
that used for SDSS public data releases. We cannot guarantee that the
values here will exactly match those in the data release in which these
data are included. In particular, we expect the photometric calibrations
to differ by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data release paper,
Adelman-McCarthy et al. (2006, ApJS, 162, 38), when using the data or
referring to the technical documentation.
- GCN Circular #6515
Adria C. Updike, Dieter H. Hartmann (Clemson University), Gary Henson
(ETSU), Robert Mesler, Christina Bunker, and Jason Carson (ETSU/SARA REU
program) report:
We imaged the field of GRB 070612 (GCN 6509, Grupe et al.) beginning 1
hour and 17 minutes after the trigger (282006) with the SARA 0.9m at
Kitt Peak under decent weather conditions and high airmass. We obtained
20 minutes of exposures in the R band before the target set.
We detect a source at RA 08:05:28.533, Dec +37:16:09.57 (+/- 1") at an
R-band magnitude of 17.16 +/- 0.17 calibrated relative to 5 USNO B1.0
stars. It appears that this coincides with a source in the SDSS images
near this location (GCN 6510, Cool et. al), but appears significantly
brighter than two nearby sources of similar magnitude. Thus, we
identify this as a possible afterglow signature, however we cannot
establish whether or not it is fading.
We encourage further observations.
The SARA Homepage can be found at:
http://saraobservatory.org
This message may be cited.
- GCN Circular #6522
S. D. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(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 070612A (trigger #282066)
(Grupe, et al., GCN Circ. 6509). The BAT ground-calculated position is
RA, Dec = 121.355, 37.258 deg which is
RA(J2000) = 8h 5m 25.2s
Dec(J2000) = 37d 15' 30"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 11%.
The mask-weighted light curve shows two main overlapping peaks
with the first starting at ~T-20 sec and the second ending at ~T+400 sec.
The two peaks are at T+5 and T+200 sec. T90 (15-350 keV) is 370 +- 10 sec
(estimated error including systematics).
The time-averaged spectrum from T-4.7 to T+418 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.69 +- 0.10. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+10.39 sec in the 15-150 keV band
is 1.5 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
- GCN Circular #6525
S. B. Cenko, E. O. Ofek (Caltech) and D. B. Fox (Penn State) report on
behalf of a larger collaboration:
We have imaged the field of GRB 070612A (Grupe et al., GCN 6509) with the
automated Palomar 60-inch telescope. Images were taken in the Sloan i'
filter beginning at 4:27:29 12 June UT (~ 1.8 hr after the burst) at large
airmass (> 2.5).
Inside the BAT error circle we identify a bright, stationary, variable
source located at coordinates (J2000.0):
RA: 08:05:29.61
Dec: +37:16:15.2
The object increases in brightness over the duration of our exposure,
ranging from i' = 16.97 in our first image to i' = 16.27 approximately 2.2
hours after the burst.
Given the brightness, we consider it likely this is the same candidate
proposed by Updike et al. (GCN 6515), despite the fact that their position
differs from ours by ~ 14". Furthermore, as first noted by this group,
there is a faint galaxy underlying the OT visible in the SDSS images of
this field (Cool et al., GCN 6510) located at RA: 08:05:29.64, Dec:
+37:16:14.6 (J2000.0). The photometric redshift, taken from the SDSS
database, for this putative host is z = 0.096 +/- 0.023.
Altogether, GRB 070612A has 1) a very long duration (t90 ~ 370 s;
Barthelmy et al., GCN 6522), 2) a bright, rising optical afterglow at t ~
2 hr, and 3) an underlying, nearby (z ~ 0.1) putative host galaxy. In all
these ways it is similar to XRF 060218. Despite its proximity to the
sun (~ 38 degrees away and setting), we encourage follow-up observations
at all wavelengths while still possible to further investigate this
interesting source and search for signs of an associated supernova.
- GCN Circular #6526
N. Mirabal, I. D. McGreer, J. P. Halpern (Columbia U.),
M. Dietrich, B. M. Peterson (Ohio State U.) report on
behalf of the MDM GRB follow-up team:
"We observed the candidate optical afterglow of Swift
GRB 070612A (Updike et al. GCN 6515, Cenko et al.
GCN 6525) using the MDM 2.4m telescope. Preliminary
calibration with respect to USNO magnitudes
of nearby stars yields r' ~ 19.0 +/- 0.3 on June 13 03:59 UT
and i' ~ 18.4 +/- 0.2 on June 13 03:49 UT respectively.
These measurements indicate that the afterglow
has faded with respect to previous reports."
- GCN Circular #6529
J.P. Norris (U.Denver), S.D. Barthelmy (GSFC), N. Gehrels (GSFC):
Spectral lag analysis of the two main emission episodes in GRB 070612A,
described in GCN Circ. 6522 (Barthelmy et al.) indicate that this burst
has relatively long lags, comparable to and longer than that of GRB 980425
(~ 2-3 s), the first burst associated with a supernova.
For the first, brighter FRED-like pulse structure, the lag measurement
between BAT energy bands 15-25 keV and 50-100 keV (25-50 and 100-350 keV)
is 2.5 s +2.1-1.8 s (2.5 +0.7-0.5 s).
For the second, dimmer pulse structure, the 15-25 keV to 50-100 keV
lag is 5.8 s +2.6-1.9 s. The flux in the 100-350 keV band for this
second episode was too low to make a useful measurement.
Spectral lags of several seconds indicate a relatively low luminosity
burst, consistent with the nearby host (z ~ 0.1) described in GCN Circ.
6525 (Cenko et al.).
- GCN Report 64.1
GCN_Report 64.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_64_1.pdf
by D. Grupe
at PSU
titled: "Swift observations of GRB 070612A"
- GCN Circular #6530
Adria C. Updike, Jason Puls, Dieter H. Hartmann (Clemson University),
Matt Wood (FIT), Josh Cardenzana (U Missouri - Rolla), and Shelsea
Pederson (MIT) report:
We re-imaged the field of GRB 070612A (GCN 6509, Grupe et al.) with the
SARA 0.9m telescope at Kitt Peak under decent weather conditions. We
obtained 15 minutes of R-band images beginning 24 hours after the
trigger (282006).
The afterglow (Updike et al. GCN 6515, Cenko et al. GCN 6525) is
detected at a R-band magnitude of 18.3 +/- 0.4 as calibrated relative to
9 USNO B1.0 stars, thus confirming the fading behavior.
The SARA Homepage can be found at:
http://saraobservatory.org
This message may be cited.
- GCN Circular #6531
M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama (OAO, NAOJ)
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME
collaboration:
We performed optical imaging observations (Rc and Ic) of the
field of GRB 070612A (Grupe et al., GCN 6509) with 50cm MITSuME
telescope at Okayama Astrophysical Observatory from UT 11:19 to
UT 11:27 on June 12 2007.
We coadded 4 CCD frames for each band. Exposure time of each
frame is 1 minute. We made flux calibration using USNO B1.0
catalg. We found a faint source at the position of the afterglow
candidate reported by Cenko et al. (GCN 6525, RA:08:05:29.6,
DEC:+37:16:15) in Ic band. The Ic magnitude was 17.1 +/- 0.3.
There was no source brigher than 16.7 magnitude in Rc band. Flux
calibration was made with three USNO-B stars around the object.
---------------------------------------------------------------
band mid-UT exp.time magnitude
Rc June 12 11:23 4 x 1 min. > 16.7 mag (upper limit)
Ic June 12 11:34 4 x 1 min. 17.1 mag +/- 0.3 mag
---------------------------------------------------------------
- GCN Circular #6533
T. Uehara, M. Ohno, T. Takahashi, C. Kira, Y. Fukazawa (Hiroshima U.),
T. Enoto, R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo),
K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.),
Y. Urata, K. Onda, M. Suzuki, K. Morigami, N. Kodaka, M. Tashiro, A. Endo (Saitama U.),
T. Tamagawa, Y. Terada (RIKEN), S. Hong (Nihon U.),
M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
E. Sonoda, M.Yamauchi, S. Maeno, H. Tanaka, R. Hara(Univ. of Miyazaki),
and Suzaku WAM team report:
The long burst, GRB 070612A (Swift/BAT trigger #282066; D. Grupe et al.,
GCN Circ. 6509 ), was triggered at 02:38:41 UT (=T0) by the Suzaku Wide-band
All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV.
The observed light curve shows a single peaked structure with a duration (T90)
of nearly 35 seconds. The fluence in 100-1000 keV was (8.2 +/- 2.4) * 10^-6 erg/cm^2.
The 1-s peak flux was 1.2 (+0.4, -0.3) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-4 to
T0+36 sec is well fitted by a single power law model with a photon index
of 2.5 +/ -0.3 (chi^2/d.o.f. = 31/21).
All the quoted errors are at statistical 90% confidence level, in which
the systematic uncertainties are not included.
The WAM light curve of this event is available at the following web cite.
http://www.astro.isas.ac.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Circular #6534
N. Mirabal, I. D. McGreer and J. P. Halpern (Columbia U.)
report on behalf of the MDM GRB follow-up team:
"We have re-observed the optical afterglow of Swift
GRB 070612A (Updike et al. GCN 6515, Cenko et al.
GCN 6525) in the R and i' filters using the same
instrumental setup as in Mirabal et al. (GCN 6526).
Preliminary calibration referenced to the SDSS photometry
of field stars (Cool et al. GCN 6510) shows that the
afterglow has faded by 1.88 mag since the previous night.
This corresponds to a decay rate steeper than ~ -2.5, which
might represent the end of an optical flash from reverse shock emission
(Meszaros & Rees 1997, ApJ, 306, 301; Sari & Piran 1999,
ApJ, 496, L1). Alternatively, the steepening could be the
signature of a "jet break". Further observations are encouraged
to distinguish between various possibilities."
- GCN Circular #6535
A. C. Updike (Clemson University), P. A. Milne (Steward Observatory), G.
G. Williams (MMT), and D. H. Hartmann (Clemson University) report on
behalf of the Super-LOTIS collaboration:
We observed the field of GRB 070612A with the 0.6m Super-LOTIS telescope
on June 13, beginning at 03:42:00 UT, or 25 hours and 4 minutes after the
burst trigger (282066). In 6 minutes of stacked exposures, we marginally
detect the afterglow (Updike et al. GCN 6515, Cenko et al. GCN 6525) at an
R-band magnitude of 17.73 +/- 0.76 as calibrated relative to 6 USNO B1.0
stars.
This message may be cited.
- GCN Circular #6549
A.J. van der Horst, R.A.M.J. Wijers, K. Wiersema (University of Amsterdam),
and E. Rol (University of Leicester) report on behalf of a larger
collaboration:
"We observed the position of the GRB 070612A afterglow (GCN 6509) at 4.9 GHz
with the Westerbork Synthesis Radio Telescope at June 15 8.10 UT to 20.09 UT,
i.e. 3.23 - 3.73 days after the burst.
We tentatively detect a radio source at 3 sigma significance, located at the
position of the optical counterpart (GCN 6515, GCN 6525), with a flux of
78 +/- 25 microJy.
Further observations at radio wavelengths of this afterglow are planned and
encouraged, especially given the suggested association with a nearby
low-redshift host galaxy (GCN 6525).
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
- GCN Circular #6555
D. Malesani, J. Hjorth, J.P.U. Fynbo (DARK), J. Sollerman (DARK &
Stockholm obs.), G. Olofsson (Stockholm Obs.), D. Paraficz (NOT & DARK),
M. Durant (IAC), report:
We observed the afterglow (Updike et al., GCN 6515; Cenko et al., GCN
6525) of GRB 070612A (Grupe et al., GCN 6509) with the NOT telescope at
several epochs. The afterglow is detected in all our images. The galaxy
seen in the SDSS images (first noted by Updike et al., GCN 6515) may be
resolved into two components, one roughly coincident with the afterglow,
and the other 1.8" South.
From our measurements, the light curve has been slowly declining between
Jun 14.9 and Jun 17.9 UT. The data after 1 day (including the MDM points
by Mirabal et al., GCNs 6526, 6529) are consistent with a steep power-law
decay (alpha ~ 3) superimposed on a constant contribution. From our latest
image (Jun 17.90 UT) we measure R=21.45+-0.2 (against USNO-B1.0), where
the error is mostly due to calibration. This value includes some
contribution from the underlying host galaxy.
If the redshift of the GRB is z=0.096, our measurement implies that any
associated SN was fainter than SN1998bw by at least 1.5 mag (and likely
more, after considering the host contribution). Alternatively, an
unextinguished SN as bright as SN1998bw should be at redshift >0.2. We
note that the SDSS catalog provides two redshift determinations for this
object, the largest one being z=0.42+-0.14:
http://cas.sdss.org/astrodr5/en/tools/explore/obj.asp?id=587728931336684102
Our data are consistent with a SN akin to SN1998bw at z=0.4. In this case,
a rebrightening by ~0.5 mag is expected during the next week. Observations
will continue for as long as visibility contraints allow.
- GCN Circular #6556
S. B. Cenko (Caltech), D. B. Fox, A. Cucchiara (Penn State), B. P. Schmidt
(Australia National University), E. Berger (Carnegie), P. A. Price (IfA),
and K. C. Roth (Gemini) report on behalf of a larger collaboration:
Starting on 2007 June 17 at 06:10 UT we used GMOS on the Gemini North
telescope to obtain a 600 s spectrum of the afterglow + host galaxy of GRB
070612A (Grupe et al., GCN 6509). The spectrum was taken in twilight at
very high airmass (~ 3.2) and covers the wavelength range ~ 4000-8120 A.
We find a strong, broad (~ 10 A) emission line at ~ 6229 A that, based on
the lack any blueward emission features, we identify as [O II] 3727 at
z=0.617. We also notice another possible emission feature at the very red
edge of our spectrum corresponding to H-beta at the same redshift. No
other features are detected either in emission nor in absorption.
We note that this redshift is significantly larger than the original SDSS
photometric redshift (z ~ 0.1) noted by Cenko, Ofek, and Fox (GCN
6525), and is more consistent with the larger redshift (z ~ 0.4) noted by
Malesani et al. (GCN 6555). The larger distance would naturally explain
the faintness of any associated SN emission, as noted by these authors.
We wish to thank and acknowledge the effort of the staff at Gemini North
in undertaking these difficult observations.
- GCN Circular #6558
P. D'Avanzo, S. Covino (INAF-OAB), M. Della Valle (INAF-OA Arcetri), E.
Pian (INAF - OATs), G. Tagliaferri on behalf of the CIBO collaboration,
P. Mazzali (INAF - OATs & MPA), A. Magazzu` and Noemi Pinilla-Alonso
(INAF - TNG) report:
We observed the afterglow (Updike et al., GCN 6515; Cenko et al., GCN
6525) of GRB 070612A (Grupe et al., GCN 6509) with the Italian 3.6m TNG
telescope equipped with
the DOLORES camera on 2007 Jun 18.89 and 19.90 UT. Because of visibility
constraints, images have been taken at high airmass (~ 3). The average
seeing was of about 1.7". An extended object is clearly visible at the
position of the optical afterglow (Cenko et al., GCN 6525) and its
brightness remains constant at both epochs at a level of R ~ 21.4
(calibrated against the USNO B1.0 catalog). This is consistent to what
reported by Malesani et al. (GCN 6555) and suggests that the afterglow's
brightness is now below the host galaxy level.
We acknowledge the support of the TNG staff.
- GCN Circular #6566
S. Taubenberger (MPA), P. Mazzali (MPA & INAF - OATs), W. Hillebrandt
(MPA), J. Alves (CAHA), U. Thiele (CAHA), S. Pedraz (CAHA),
A. Guijarro (CAHA), M. Alises (CAHA) and E. Pian (INAF - OATs) report:
We observed the afterglow (Updike et al., GCN 6515; Cenko et al., GCN
6525) of GRB 070612A (Grupe et al., GCN 6509) with the Calar Alto 2.2m
Telescope equipped with CAFOS on 2007 Jun 13.86, 14.86 and 15.87 UT.
In all three nights images were taken in the BVRI bands, at high
airmass (~ 3), and under variable seeing and transparency conditions
(2.0" - 5.6" fwhm, clear - thin clouds).
The afterglow was detected on Jun 13.86 at V = 20.40+-0.23 and
R = 19.79+-0.10 (calibrated against the Landolt field PG1633 under
photometric conditions; only measurement errors reported). In R up
to 25% of contamination from the underlying galaxy can be expected
(D'Avanzo et al., GCN 6558).
From the rest of the images only limits could be derived, in
particular V > 20.0 / 19.8 and R > 18.9 / 19.6 on Jun 14.86 / 15.87,
respectively.
Our Jun 13.86 R-band magnitude is consistent with the afterglow's
steep power-law decay suggested by observations with other telescopes
(cf. Malesani et al., GCN 6555, and references therein).
- GCN Circular #6576
A.J. van der Horst, R.A.M.J. Wijers, K. Wiersema (University of Amsterdam),
and E. Rol (University of Leicester) report on behalf of a larger
collaboration:
"We reobserved the position of the GRB 070612A afterglow (GCN 6509) at
4.9 GHz with the Westerbork Synthesis Radio Telescope at June 20 7.91 UT
to 19.76 UT, i.e. 8.22 - 8.71 days after the burst.
At the position of the optical counterpart (GCN 6515, GCN 6525) and the
tentative radio counterpart (GCN 6549), we measure a formal flux of
72 +/- 27 microJy, i.e. a possible radio source at 2.7 sigma significance.
In a combined image of the two epochs of WSRT observations, at June 15 and
June 20, the average formal flux is 53 +/- 19 microJy, a 2.8 sigma
detection. Therefore, we cannot state with certainty whether the radio
afterglow (or the possible host galaxy) of GRB 070612A is detected.
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
- GCN Circular #6583
R. Forster, M. Wright, J. Hare, J. S. Bloom, G. C. Bower (UC
Berkeley) report on behalf of a large collaboration:
"Using the Allen Telescope Array (ATA,
http://ral.berkeley.edu/ata/),
we observed GRB 070612A (Grupe et al., GCN 6509) at 1.4 GHz on 2007
June 16 UT and at 5 GHz on 2007 June 17 UT. The observations made use
of 8 antennas outfitted with dual-polarization receivers. At the
location of the optical afterglow (Updike et al., GCN 6515), we
obtained 3-sigma limits of 50 mJy at 1.4 GHz and 10 mJy at 5 GHz for
the flux density of GRB 070612A at these epochs. The data were
calibrated versus the QSS 0927+392. At L-band the 8 brightest NVSS
were measured to be located within 10% of the synthesized beamwidth
and 100 mJy of the NVSS flux densities. The limits reported herein
are consistent with the tentative WSRT detection at 4.9 GHz (Horst et
al. GCNs 6549, 6576).
A 42-antenna ATA is currently being commissioned."
This message may be cited.
- GCN Circular #6600
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB
070612A (GCN 6509) at a frequency of 4.88 GHz on 2007 June 30th at
20.66 UT. We detect the GRB afterglow at P60 optical afterglow position
(GCN 6517). The flux density of the GRB is 189+/-56 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
- GCN Circular #6714
Sabyasachi Pal, C.H. Ishwara-Chandra, Dipankar Bhattacharya and
Atish P. Kamble report on behalf of a larger collaboration:
We observed the field of GRB 070612A (Grupe et al, GCN 6509) at
1280 MHz, using the Giant Meterwave Radio Telescope, from
MJD 54305.08 to 54305.26 (UT 2007 Jul24 01:55:21 to 06:12:36).
This interval corresponds to 41.97-42.15 days after the burst.
The afterglow was not detected. The formal flux density at the
position of the optical afterglow (Cenko et al, GCN 6525)
was 109 +/- 64 micro Jy (1-sigma).
We thank the GMRT staff who made this observation possible.
GMRT is run by the National Centre for Radio Astrophysics of
the Tata Institute of Fundamental Research.
This message may be cited.
Previous IAU Circulars 