TITLE:   GCN CIRCULAR
NUMBER:  37257
SUBJECT: SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
DATE:    24/08/24 09:20:08 GMT
FROM:    leavittob@gmail.com

L. Moretti  and E. Pavoni (Leavitt Observatory, Italy), in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan),
Y. Niino (Tokyo University, Institute of Astronomy),
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Universita' degli Studi Di Salerno)
report:

We observed the field of the soft gamma repeater SGR 1E 1841-045 / Kes 73, detected by Swift BAT (DeLaunay et al., GCN 37211; Dichiara et al., GCN 37222; Roberts et. al. GCN 37234; Wen-Long Zhang et al, GCN 37240; Leonini et al. GCN 37252), with the telescope of Leavitt Observatory, Italy. Member of:

GRB/UAI - Gamma Ray Burst section of Unione Astrofili Italiani
ATA - Associazione Tuscolana di Astronomia.


Our observations started at 22:09:27 UT on 2024-08-20, i.e. about 188 min. after the Swift trigger, with a RC telescope D=250 mm F/D=8, at the following position:

RA(J2000) = 18h 41m 22s
Dec(J2000) = -04d 57' 00"

Median moon illumination of 98% and cloud coverage was present.

We co-added 6 images of 120 sec each. All images are V filtered, calibrated with master dark and master flat.

We have not detected any clearly visible sources within the error-box (3 arcmin) of the Neil Gehrels Swift Observatory position, with the following upper limit:

Start                        End                    Vlim
2024-08-20T22:09:27          2024-08-20T22:35:52    17.5

Magnitudes were estimated with the Gaia DR3 catalogue (*) and are not corrected for galactic dust extinction.


Reference:
https://leavittobservatory.altervista.org

The message may be cited.

(*) https://gea.esac.esa.int/archive/documentation/GEDR3/Data_processing/chap_cu5pho/cu5pho_sec_photSystem/cu5pho_ssec_photRelations.html