GRB 090715B
GCN Circular 9668
Subject
GRB 090715B: Swift detection of a burst with a possible optical counterpart
Date
2009-07-15T21:34:31Z (16 years ago)
From
Loredana Vetere at PSU <vetere@astro.psu.edu>
L. Vetere (PSU), A. P. Beardmore (U Leicester),
N. Gehrels (NASA/GSFC), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
C. Pagani (PSU), J. L. Racusin (PSU), B. Sbarufatti (INAF-IASFPA),
M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU) and M. A. Stark (PSU)
report on behalf of the Swift Team:
At 21:03:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090715B (trigger=357512). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 251.344, +44.827 which is
RA(J2000) = 16h 45m 23s
Dec(J2000) = +44d 49' 36"
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 100 sec. The peak count rate
was ~8000 counts/sec (15-350 keV), at ~6 sec after the trigger.
The XRT began observing the field at 21:04:00.9 UT, 46.2 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 251.3405, +44.8377 which is equivalent to:
RA(J2000) = 16h 45m 21.71s
Dec(J2000) = +44d 50' 15.7"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 39 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 53 seconds after the BAT trigger. There is a weak source in
2.7'x2.7' sub-image near the edge of the XRT error circle at the position of
RA(J2000) = 16:45:21.62
Dec(J2000) = +44:50:21.3
The estimated white magnitude 20.5 with an estimated error of 0.5 mag.
No correction has been made for the expected extinction corresponding
to E(B-V) of 0.01.
Swift autonomous slewing to new GRBs was enabled just prior to this
burst. It was disabled previously due to an anomaly with the
on-board solid state recorder. That problem is now resolved.
Burst Advocate for this burst is L. Vetere (vetere AT astro.psu.edu).
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 Circular 9670
Subject
GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
Date
2009-07-16T00:25:24Z (16 years ago)
From
Carole Mundell at ARI, JMU,Liverpool <cgm@astro.livjm.ac.uk>
R.J. Smith, C.G. Mundell, A. Melandri, I.A. Steele, S. Kobayashi, C.J.
Mottram, D.F. Bersier, Z. Cano (Liverpool JMU), A. Gomboc (Ljubljana), C.
Guidorzi (INAF-OAB) report:
"The 2-m Liverpool Telescope robotically followed up GRB090715
(SWIFT trigger 357512; Vetere et al. GCN 9668) beginning 11.07 min after
the GRB trigger time.
An uncatalogued course is detected at:
16 45 21.67 +44 50 21 (J2000) (positional uncertainty +/-1")
with magnitude r' = 19.6 +/- 0.2 mag (wrt SDSS) at T=11.53 min.
Observations and analysis are ongoing.
This message may be cited"
GCN Circular 9671
Subject
GRB 090715B: NOT optical observations
Date
2009-07-16T01:42:48Z (16 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
D. Malesani (DARK/NBI), T. Augusteijn (NOT), C. Mackay, D. King, T.
Staley (IoA Cambridge), A. De Cia and P. Jakobsson (Univ. Iceland)
report on behalf of a larger collaboration:
We observed the field of GRB 090715B (Vetere et al., GCN 9668) with the
NOT equipped with StanCam, in the V, R, and I filters.
In a single 180 s exposure starting on 2009 July 16.040 UT (3.91 hr
after the GRB), we clearly detect the object reported by Vetere et al.
(GCN 9668) and Smith et al. (GCN 9670) with a magnitude R = 19.92 +-
0.03 (assuming R = 17.16 for the USNO star at 16:45:24.24, +44:50:57.3).
Although our measurement indicates only moderate fading when compared to
the value by Smith et al. (GCN 9670), the object is missing from the
SDSS frames of this field, and is thus very likely the afterglow of GRB
090715B.
GCN Circular 9672
Subject
GRB 090715B: Swift-BAT refined analysis
Date
2009-07-16T03:12:09Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU), L. Vetere (PSU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090715B (trigger #357512)
(Vetere, et al., GCN Circ. 9668). The BAT ground-calculated position is
RA, Dec = 251.337, 44.837 deg, which is
RA(J2000) = 16h 45m 20.9s
Dec(J2000) = +44d 50' 12.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a series of peaks. The first starts
at ~T-10 sec, peaks at ~T+7 sec, and returns almost to background at T+35 sec.
The second peak start at ~T+45 sec and ends at ~T+100 sec. The third peak
starts at ~T+230 sec and ends at ~T+290 sec.
T90 (15-350 keV) is 266 +- 11 sec (estimated error including systematics).
The time-averaged spectrum from T-11.6 to T+292.3 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.57 +- 0.07. The fluence in the 15-150 keV band is 5.7 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.46 sec in the 15-150 keV band
is 3.8 +- 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/357512/BA/
GCN Circular 9673
Subject
GRB090715B: WHT redshift
Date
2009-07-16T05:19:03Z (16 years ago)
From
Klaas Wiersema at U of Leicester <kw113@star.le.ac.uk>
K. Wiersema (Leicester), A. Levan (Warwick), A. Kamble (Amsterdam), N.
Tanvir (Leicester) and D. Malesani (DARK/NBI) report on behalf of a larger
collaboration:
We observed the afterglow of GRB090715B (Vetere et al, GCN 9668; Smith et
al GCN9 670) with the William Herschel Telescope, using the ISIS
spectrograph. Exposure times were 3 x 900 seconds with the R300B and R316R
grisms in the blue and red arm respectively, starting at 23:46 UT. We
detect a multitude of lines, including Lyman alpha, Lyman beta, SiII and
SII at redshift z=3.00.
We thank T. Ottosen for acquiring this dataset.
GCN Circular 9674
Subject
GRB 090715B: Swift XRT Refined Analysis
Date
2009-07-16T05:45:40Z (16 years ago)
From
Loredana Vetere at PSU <vetere@astro.psu.edu>
L. Vetere (PSU) reports on behalf of the Swift-XRT team:
We have analysed ~2 ks of XRT data for GRB 090715B (Vetere et al. GCN
Circ. 9668), from 52 s to 10.2 ks after the BAT trigger. The data
comprise 471 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The refined XRT position for this burst is
Ra, Dec 251.340 44.838 which is:
RA(J2000) = 16h 45m 21.7s
Dec(J2000) = +44d 50' 18.1"
The light curve shows multiple peaks in WT and a power-law decay in PC
with a
decay index of alpha=1.1(+/-0.2).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.84 (+/-0.02). The
best-fitting absorption column is 1.09 (+/-0.02) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.3 (+/-0.3) and a
best-fitting absorption column of 1.4 (+/-0.1) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 x 10^-11 (5.8 x 10^-11) erg cm^-2
count^-1.
If the light curve continues to decay with a power-law decay index of
1.1, the count rate at T+24 hours will be 0.02 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.6 x
10^-13 (1.2 x 10^-12) erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 9675
Subject
GRB 090715B: Observation of the optical afterglow
Date
2009-07-16T08:27:41Z (16 years ago)
From
Angelo Antonelli at Obs. Astro. di Roma <a.antonelli@oa-roma.inaf.it>
L. A. Antonelli (INAF-OAR), S. Marinoni (INAF-TNG), F. Montalvo (UNAM-
OAN), A. Vazquez (UNAM-IA) report:
We observed the field of GRB 090715B (Vetere et al., GCN 9668) with
the 1.5 m Telescope in San Pedro Martir (BCN-Mexico) equipped with
LaRuca, in the B, V, and R filters.
We started observations on 2009 July 16.1729 UT (7.07 hrs after the
burst) and we detect the object reported by Malesani et al., (GCN
9671), Smith et al. (GCN 9670) and Vetere et al. (GCN 9668) in all
filters. The object has a magnitude R = 20.4 +- 0.1 (calibrated
against USNO B1). The object has faded with respect of the value
reported by Malesani et al., (GCN 9671) with a decay index of 0.77
+-0.39. Due to its fading behavior we can confirm that it is the
optical afterglow of GRB 090715B.
This message can be cited.
GCN Circular 9676
Subject
GRB 090715B: Enhanced Swift-XRT position
Date
2009-07-16T11:11:26Z (16 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2329 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090715B, 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 = 251.33969, +44.83889 which is equivalent
to:
RA (J2000): 16h 45m 21.53s
Dec (J2000): +44d 50' 20.0"
with an uncertainty of 1.5 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, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 9677
Subject
GRB 090715B: break in the optical afterglow decay
Date
2009-07-16T11:49:28Z (16 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), Z. Cano, A. Melandri, C.G. Mundell,
R.J. Smith, I.A. Steele, D. Bersier, S. Kobayashi (Liverpool JMU),
A. Gomboc (U. Ljubljana) on behalf of a large collaboration report:
We began observing the Swift GRB 090715B (Vetere et al. GCN Circ. 9668)
with the Liverpool Telescope (LT) on July 15, 21:14:19 UT
(11.0 min post BAT trigger) with the SDSS riz filters,
confirming the detection of the optical afterglow seen by
Swift-UVOT (Smith et al. GCN Circ. 9670; Malesani et al GCN
Circ. 9671; Antonelli et al. GCN Circ. 9675).
Observations with the LT carried on until 5.6 hours post burst.
Our measurements are in agreement with the value reported by
Malesani et al. (GCN Circ. 9671) after correcting for the
different calibration.
We also observed the OT with the Faulkes Telescope North (FTN)
from July 16, 09:45:46 UT (i.e., at 12.71 hours) with the R filter.
The light curve in the r filter from 0.18 to 12.7 hours can be
fitted with a broken power-law with alpha1=0.25 +/- 0.02,
t_break =18 (-3, +12) ks, alpha2~0.7.
Telescope Mid Time Exposure Filter Mag
(hours) (s)
------------------------------------------------------
FTN 12.90 1200 R 20.98 +- 0.05
------------------------------------------------------
Calibration was performed against the SDSS star mentioned
by Malesani et al. (GCN 9671), assuming r'=17.74 and R=17.54.
GCN Circular 9678
Subject
GRB 090715B: Swift/UVOT followup observations
Date
2009-07-16T12:32:09Z (16 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. Breeveld (MSSL/UCL) and L. Vetere (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090715B
53 s after the BAT trigger (Vetere et al., GCN Circ. 9668).
The optical afterglow reported in Vetere et al., GCN 9668 and
confirmed by Smith et al., GCN 9670, Malesani et al., GCN 9671,
Wiersema et al., GCN 9673 and Antonelli et al., GCN 9675 is detected
by the UVOT only in the initial white exposure. The detected magnitude
and preliminary 3-sigma upper limits obtained using a 3" aperture and
the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposure and subsequent summed exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 53 203 147 20.37 +/- 0.15
white 4052 4252 196 >21.3
v 5989 22687 795 >21.0
b 3848 4047 197 >20.3
u 266 16495 428 >21.2
w1 12053 16278 894 >21.2
m2 6195 10367 826 >21.0
w2 4258 22065 995 >21.4
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 9679
Subject
Konus-Wind and Konus-RF observations of GRB 090715B
Date
2009-07-16T12:52:47Z (16 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:
The long GRB 090715B (Vetere et al., GCN 9668)
triggered Konus-Wind at T0=75799.008 s UT (21:03:19.008),
and Konus-RF instrument onboard CORONAS-PHOTON s/c
at T0(KRF)=75798.895 s UT (21:03:18.895).
The burst had a multi-peaked structure with a duration of ~100 s.
The Konus-Wind light curves of this GRB are available at
http://www.ioffe.ru/LEA/GRBs/GRB090715_T75799/
As observed by Konus-Wind, the burst had a fluence
of 9.3(-1.1,+1.5)x10-6 erg/cm2,
and a 256-ms peak flux, measured from T0+4.912 s,
of 9.0(-2.5,+2.5)x10-7 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+82.176 s) is well fitted
(in the 20 keV - 2 MeV range) by a power-law with
exponential cutoff (CPL) model:
dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak), for which:
the photon index alpha = -1.1(-0.34,+0.4), and
the peak energy Ep = 134(-30,+56) keV (chi2 = 57/61 dof).
The spectrum at the maximum count rate,
measured from T0 to T0+8.448 s, is also well fitted
(in the 20 keV - 2 MeV range) by CPL model, for which:
the photon index alpha = -0.86(-0.20,+0.22), and
the peak energy Ep = 178(-23,+33) keV (chi2 = 49/61 dof).
All the quoted values are preliminary.
The quoted errors are at the 90% confidence level.
GCN Circular 9681
Subject
GRB 090715B: MASTER optical limit
Date
2009-07-16T13:32:17Z (16 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
D.Kuvshinov, V. Lipunov, V.Kornilov, E. Gorbovskoy,
A.Belinski, A. Krylov, N.Shatskiy, N.Tyurina, P.Balanutsa, V.V.Chazov,
P.V.Kortunov
Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parkhomenko,
Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinski, I.Zalognikh, T.Kopytova, Alexander Popov
Ural State University, Kourovka
S.Yazev, K.Ivanov
Irkutsk State University
MASTER robotic telescope (MASTER-Net: http://observ.pereplet.ru,
355 mm, 6 square degrees, 16Mpx Apogee CCD) located
at Vostrykovo (Moscow) responded to the GRB 090715B (Swift
trigger 357512, L. Vetere , GCN 9668), producing images
beginning 19 s after the GCN notice time. An automated response took
the first image at 21:11:18 UT, 8m 04s after the burst, under summer
Moscow sky.
We have 160 images with 30 sec exposition each.
These unfiltered images are calibrated relative to USNO 08.R+0.2B (Usno
A2.0).
Individual images have limiting magnitudes ranging from 17.8-17.0; we
set the following specific limits.
GRB_time start UT end UT t_exp(s) mlim Coadd?
-------------------------------------------------------------------
484 - 514s 21:11:18 21:41:18 30 17.8 no
484 - 699s 21:11:18 21:14:57 90 18.5 3
484 - 6699S 21:11:18 22:54:27 3330 20.0 111
Robot do not detect OT with limit 20.0 .
The message may be cited.
mailto: lipunov@sai.msu.ru
GCN Circular 9684
Subject
GRB 090715B: Lick observations
Date
2009-07-17T17:28:04Z (16 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. Choi, A. Morton and M. Ganeshalingam (UC Berkeley) report:
We obtained a series of R-band exposures of the optical transient
associated with GRB 090715B (GCN 9668, Vetere et al.; GCN 9670, Smith et
al.) at the 1-meter Nickel telescope at Lick Observatory under clear skies
and good seeing. The transient is detected in individual frames. We
report the following magnitudes relative to the calibration star of
Malesani et al. (GCN 9671):
t_start(UT) exp(s) mag t-t0(hr)
06:17:06.10 120 R = 20.23 +/- 0.21 9.23
06:27:36.17 200 R = 20.27 +/- 0.16 9.41
06:31:53.21 200 R = 20.06 +/- 0.14 9.48
06:42:53.80 300 R = 20.48 +/- 0.17 9.66
06:54:57.78 300 R = 20.40 +/- 0.16 9.86
07:01:01.97 300 R = 20.39 +/- 0.20 9.96
07:07:07.30 300 R = 20.24 +/- 0.14 10.07
07:19:01.36 300 R = 20.47 +/- 0.18 10.26
07:32:15.82 300 R = 20.71 +/- 0.23 10.44
A stack of all images gives an average magnitude of R = 20.23 +/- 0.07.
GCN Circular 9687
Subject
GRB 090715B: further NOT optical observations
Date
2009-07-18T15:31:46Z (16 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
D. Malesani (DARK/NBI), G. C. Cox (NOT), C. Mackay, D. King, T. Staley
(IoA Cambridge), and P. Jakobsson (Univ. Iceland) report on behalf of a
larger collaboration:
We observed again the field of GRB 090715B (Vetere et al., GCN 9668)
using the NOT telescope equipped with the StanCam instrument. The
optical afterglow (Vetere et al., GCN 9668; Smith et al., GCN 9670) is
well detected in the V and R filters, and is still bright. Using the
same reference star as in GCN 9671, we measure R ~ 21.3 on mean time
July 17.94 UT (2.06 days after the GRB).
Assuming an unbroken power-law fading (Fnu propto t^-alpha), the
corresponding decay index is alpha ~ 0.44, which is unusually flat at
such late epoch (although not unprecedented). Our measurement is also
consistent within the uncertainties with the broken power-law fit
reported by Guidorzi et al. (GCN 9677).
DM thanks Carole G. Mundell and Cristiano Guidorzi for discussion.
GCN Circular 9695
Subject
GRB 090715B: VLA radio detection
Date
2009-07-20T19:54:32Z (16 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on behalf of a
larger collaboration:
"We used the Very Large Array (VLA) to observe the field of view towards
the GRB 090715B (GCN 9668) at a frequency of 8.46 GHz on 2009 Jul. 20.14
UT. We clearly detect the GRB afterglow at the Swift UVOT afterglow
position (GCN 9668). The peak flux at the GRB afterglow position is
231+/-47 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 9720
Subject
GRB 090715B: Late-time Lick 3m observations
Date
2009-07-28T06:13:01Z (16 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, N. R. Butler, and S. B. Cenko (UC Berkeley) report:
We obtained additional, late-time imaging of the field of GRB 090715B
(GCN 9668, Vetere et al.; GCN 9670, Smith et al.) with the Lick 3m
telescope (+PFCam) in the R-band filter under dark skies, good seeing
conditions and thin cloud cover. Observations were conducted on the
night of 2009-07-24 (UT) between 04:46 and 06:15 UT, and consisted of
seven 300-second exposures followed by four 600-second exposures.
The afterglow is faintly detected in the combined image. Photometry
relative to the reference star of Malesani et al. (GCN 9671) gives a
magnitude of R = 23.6 +/- 0.3 mag at this time (t = 8.35 days after the
GRB).
Relative to the NOT observation at 2.06 days (Malesani et al., GCN
9687), this corresponds to a decay index of alpha ~ 1.5, indicating that
the unusually long period of slow fading has ended and the optical
afterglow has resumed a "normal" power-law decay.
GCN Circular 9927
Subject
GRB 090715B: Skynet/PROMPT Detections
Date
2009-09-21T04:34:58Z (16 years ago)
From
Josh Haislip at U.North Carolina <haislip@physics.unc.edu>
J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A.
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander
report:
Skynet observed the Swift/BAT localization of GRB 090715B (Vetere et al.,
GCN 9668) with three of the 16" PROMPT telescopes at CTIO beginning 3.1
hours after the trigger in UBRI.
We detect the afterglow (Vetere et al., GCN 9668). Stacking only images
that increase the limiting magnitude yields:
mean 1-sig.
1-sig.
time sys. stat.
since cal. cal. cal.
trig. tel. exp. fil. magnitude stars* unc. unc.
(h) (# x s) (mag) (mag)
3.4 PROMPT-3 12 x 80 U > 17.5 (3 sig.) 10 SDSS 7 0.094 0.001
3.8 PROMPT-5 40 x 80 I 19.80 +0.40 -0.29 93 SDSS 7 0.268 0.000
3.8 PROMPT-4 41 x 80 R 20.31 +0.20 -0.17 78 SDSS 7 0.151 0.000
4.0 PROMPT-3 29 x 80 B > 20.8 (3 sig.) 37 SDSS 7 0.134 0.000
* Transformed using Jester et al., 2005, ApJ, 130, 873.