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GCN Circular 35296

Subject
GRB231115A: TURBO Pre-Burst Optical Upper Limits
Date
2023-12-06T21:42:43Z (a year ago)
From
Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>
Via
email
R. Strausbaugh (Eastern Illinois University), Daniel Warshofsky (UMN), Pat Kelly (UMN), Mandeep S. S. Gill (UMN), Alexandre Toscano (UMN), Yilin Lu(UMN), Sydney Leggio (UMN), Aksinya Kamenshikova (UMN) report on behalf of a larger collaboration:


We observed M82, including the localization region for the Fermi GRB 231115A (Fermi GBM team, GCN 35035), with the Total-Coverage Ultrafast Response to Binary-Mergers Observatory (TURBO) prototype telescope in St. Paul, Minnesota, USA, as part of a high-cadence ongoing survey for transients in nearby galaxies.  We visited the field 55 times on November 15 UT, with the last visit occurring at 9:06 UT in SDSS r and g bands respectively (corresponding to 6.5 hours before the GRB trigger time).


Each exposure is 30 seconds.  We do not detect a source at the same location as the GROWTH-India counterpart (Kumar et al., GCN 35041) in either band.


The 3-sigma upper limits in the table below are calculated using the Pan-STARRS catalog as reference, and are not corrected for Galactic extinction.


The TURBO prototype in St. Paul consists of two co-mounted 11-inch telescopes each with a 6.6 square degree field of view.


TURBO, which is under construction, will consist of two arrays of 8 pairs of co-mounted 11-inch telescopes at two dark-sky sites: Magdalena Ridge Observatory, New Mexico, USA and Skinakas Observatory, Crete, Greece.


mjd

g upper limit (AB)

r upper limit (AB)

60262.97035880

-

16.0

60262.97244213

16.9

-

60263.00063657408


-

15.9

60263.00407407407

-

15.7

60263.007106481484

-

16.1

60263.012094907404

-

15.6

60263.015555555554

-

15.9

60263.01940972222

-

16.0

60263.02327546296

-

15.9

60263.02715277778

-

16.3

60263.03057870371

-

16.1

60263.034212962964

-

16.1

60263.03765046296

-

16.4

60263.04111111111

-

15.7

60263.04293981481

-

15.8

60263.04591435185

16.5

15.7

60263.04896990741

-

16.4

60263.05202546297

16.5

15.8

60263.055

16.5

15.6

60263.058020833334

-

15.8

60263.061006944445

-

16.0

60263.06407407407

-

15.9

60263.070497685185

-

16.3

60263.07403935185

-

16.2

60263.07748842592

-

15.8

60263.080462962964

-

16.3

60263.08472222222

-

16.1

60263.087592592594

16.5

16.4

60263.09365740741

16.4

16.3

60263.09645833333

15.9

16.5

60263.099375

-

16.4

60263.1171412037

-

16.7

60263.120150462964

16.3

16.3

60263.12315972222

-

15.4

60263.14434027778

16.6

15.6

60263.14716435185

16.0

15.7

60263.15039351852

15.7

16.1

60263.15372685185

16.5

16.0

60263.156539351854

15.8

16.0

60263.159421296295

16.0

16.3

60263.162314814814

16.6

15.8

60263.165138888886

15.8

16.8

60263.16957175926

16.3

16.2

60263.172997685186

16.4

-

60263.176516203705

16.5

16.5

60263.19818287037

16.8

15.8

60263.21885416667

16.9

16.8

60263.22230324074

17.4

17.0

60263.24633101852

17.3

16.4

60263.268900462965

17.3

16.6

60263.27537037037

16.9

16.9

60263.27885416667

17.3

17.0

60263.283229166664

17.0

16.9

60263.28666666667

16.9

17.0

60263.29603009259

17.4

16.8


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