GCN Circular 3478
Subject
GRB050525: Optical observations
Event
Date
2005-05-25T14:07:59Z (21 years ago)
From
Aaron Price at AAVSO <aaronp@aavso.org>
D. T. Durig (Cordell-Lorenz Observatory, University of the South), A. Oksanen
(Nyrola Observatory), C. Pullen (AAVSO) and A. Price (AAVSO) report on behalf of
the AAVSO International High Energy Network on optical observations of GRB050525
(GCN #3466; Band et al.):
An afterglow candidate is found at the location reported by Rykoff et al. (GCN
#3468) and Band et al. (GCN #3465). At 08:13 UT it is detected at an unfiltered
magnitude of 18-19 (fading over 100 mins centered on 08:13UT). The USNO star near
18 32 34.5 +26 20 24 can not completely be resolved from the afterglow candidate.
Full details and FITS image URL is below.
Name: Dr. Douglas T. Durig
email: ddurig@sewanee.edu
Observer: Dr. D. T. Durig ( CLW01)
Site: Cordell-Lorenz Observatory
Location: Sewanee, Tenn., USA
LatitudeLongitude: 35 12 N 85 55 W
Elevation: 600 m
Scope: SCT 0.30 m
ScopeFocalRatio: f/5.8 1765 mm
CCDVendor: SBIG STL-1001E
CCDDetector: KAF 1001E
CCDSize: 1024x1024
CCDPixelScale: 2.8
CCDFOV: 48x48 full, 12x12 quarter frame cropped
Object: GRB050525
ObsDate: 2005 05 25
ObsMidPointTime: 08 13 25
TimePerFrame: 120 sec
NumberOfFrames: 75
Filters: CR
Processing: dark, flat, register, co-add, 1/4 frame crop
Seeing: 5-6 arc sec
LimitingMag: 19.5-20 ???
Sky: very clear but breezy with Bright Moonlight
afterglowmag: 18-19
afterglowerr: 1
compstars: 1300 UCAC ref stars in full frame
Report: The USNO star near 18 32 34.5 +26 20 24 can not completely be resolved
from the afterglow candidate, but I do see it fade by around 1 mag over a little
over 100 min by summing a series of 30 consecutive 120 sec exposures. I get a
measured position of 18 32 33.9 +26 20 23 and 18 mag at 7:23 UT falling to 19 mag
at 9:03 UT, but this includes some contribution from the USNO star.
comments: UT dec.day CR mag
7:23:28 25.30796 18.0
7:40:09 25.31955 18.2
7:56:43 25.33105 18.3
8:13:25 25.34265 18.3
8:30:10 25.35428 18.3
8:46:49 25.36584 18.6
9:03:28 25.37741 19.0
A FITS image has been uploaded to
ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB050525_2453516.00275_.fits
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.