Swift Trigger: 1090472;

Presumed name: GRB 211221A

BAT	05^h 15^m 45.12^s, +00° 56′ 24.0″
position:	(78.938, +0.940 ± 180″)
XRT	05^h 15^m 35.57^s, +00° 54′ 51.2″
position:	(78.89820, 0.91421 ± 3.7″)
UVOT	No position available.
Galactic N_HI:	9.54×10²⁰ cm^-2
Galactic E(B-V):	0.122 mag

Best RA:	05^h 15^m 35.57^s	= 78.89820 d
Best Dec:	+00° 54′ 51.2″	= 0.91421 d

Gal Lat:	-20.74
Gal Long:	200.62

Sun angle:	155.12°, -11.3 hr East of Sun

Galaxies within 200 of XRT position

	RA*	Dec*	Redshift		Catalogue
10.8	78.8996	0.9167			NED
16.6	78.8954	0.9181			NED
19.1	78.8929	0.9136			NED
19.3	78.8929	0.9136		B=21.7, R2=19.9	SSS
19.4	78.8928	0.9136		R1=18.6, R2=19.3	USNO-B1
19.6	78.8929	0.9136	0.452100		NED
19.6	78.8929	0.9136			NED
19.6	78.8928	0.9135		B=21.3, R=19.4	APM-N
27.0	78.9033	0.9194			NED
27.9	78.9033	0.9083			NED
30.3	78.9064	0.9124		B=19.8, R2=18.6, i=18.3	SSS
35.5	78.9050	0.9211			NED
40.7	78.9062	0.9222			NED
40.8	78.8994	0.9255		B=21.0, R=18.8	APM-N
40.9	78.8991	0.9255		B2=20.8, I=18.1, R1=19.3, R2=19.1	USNO-B1
40.9	78.8992	0.9256			NED
40.9	78.8993	0.9255		B=20.9, R2=19.0, i=18.2	SSS
41.2	78.9000	0.9256			NED
41.5	78.9004	0.9256			NED
48.6	78.8888	0.9239			NED
48.7	78.8889	0.9240		B1=16.1, B2=15.8, I=14.7, R1=15.3, R2=15.3	USNO-B1
48.9	78.9017	0.9273		B=21.2, R=20.0	APM-N
51.7	78.9038	0.9011			NED
60.2	78.8843	0.9049		R1=19.4, R2=19.8	USNO-B1
60.4	78.8842	0.9047			NED
60.4	78.9100	0.9022			NED
61.3	78.8900	0.9292			NED
61.9	78.8808	0.9142			NED
61.9	78.8821	0.9083			NED
62.3	78.8896	0.9294			NED
65.0	78.8983	0.9322			NED
65.7	78.9117	0.9264			NED
69.2	78.9096	0.8989			NED
74.6	78.9104	0.9308			NED
75.3	78.9107	0.9310		B=20.4, R2=19.1, i=18.2	SSS
75.9	78.9142	0.9003			NED
77.0	78.9008	0.9356			NED
77.3	78.8958	0.8928			NED
77.5	78.9118	0.9309		B=20.4	SSS
80.0	78.9025	0.9361			NED
80.2	78.9029	0.9361			NED
84.1	78.9133	0.8967			NED
84.2	78.8775	0.9033			NED
84.2	78.8775	0.9032		B2=21.1, I=18.4, R1=19.1, R2=19.2	USNO-B1
85.9	78.8875	0.9356			NED
86.2	78.8854	0.8939			NED
86.5	78.9175	0.9281			NED
86.7	78.8822	0.9322		B=21.2, R=20.0	APM-N
86.8	78.8754	0.9217			NED
87.9	78.8739	0.9117		B=16.7, R=15.7	APM-N
88.2	78.9021	0.9384		B=20.6, R2=20.1	SSS
88.5	78.8738	0.9119			NED
89.3	78.9158	0.9319			NED
89.4	78.9004	0.8894			NED
90.5	78.9229	0.9114			NED
91.9	78.8850	0.9361			NED
93.3	78.8883	0.9381			NED
93.7	78.9121	0.9361			NED
94.3	78.9142	0.9350			NED
94.7	78.9079	0.9386			NED
95.1	78.9150	0.8939			NED
96.2	78.9188	0.8972			NED
97.9	78.8896	0.8883			NED
98.8	78.9196	0.9311			NED
99.2	78.9087	0.9397			NED
99.4	78.8917	0.8872			NED
99.6	78.8708	0.9181		B1=18.9, B2=18.7, I=18.3, R1=18.3, R2=17.9	USNO-B1
100.1	78.8717	0.9233			NED
100.9	78.9229	0.9278			NED
101.0	78.9050	0.9414			NED
101.5	78.9229	0.9011			NED
101.9	78.8704	0.9203			NED
102.7	78.8842	0.8894			NED
103.1	78.9235	0.9277		B=19.1, R2=18.3, i=18.1	SSS
103.1	78.8983	0.8856			NED
104.2	78.9146	0.9381			NED
105.0	78.8946	0.9431			NED
105.5	78.9225	0.8978			NED
105.5	78.9242	0.9277		B=16.5, R=14.9	APM-N
105.8	78.9243	0.9278		B=17.6, R2=14.7, i=14.0	SSS
106.4	78.9246	0.9278			NED
106.9	78.8688	0.9094			NED
107.4	78.8704	0.9033		B=21.2, R=20.0	APM-N
108.8	78.9050	0.8847			NED
109.6	78.9258	0.9272			NED
110.0	78.8742	0.8956			NED
111.1	78.9275	0.9231			NED
111.8	78.9121	0.9419			NED
113.3	78.8825	0.8869			NED
113.8	78.9008	0.8828			NED
114.1	78.8821	0.8869			NED
114.4	78.8679	0.9236			NED
116.0	78.8658	0.9119			NED
116.7	78.8779	0.8889			NED
117.2	78.9067	0.9456			NED
118.1	78.9217	0.8914			NED
118.4	78.8696	0.9308			NED
118.4	78.8950	0.8814			NED
118.9	78.8720	0.8941		B=22.5	SSS
119.0	78.8704	0.9325			NED
119.7	78.8671	0.9264			NED
121.6	78.8679	0.9294			NED
121.6	78.9319	0.9126		B=22.2, R2=20.4	SSS
121.7	78.9297	0.9264		B=22.0	SSS
122.2	78.9321	0.9125			NED
122.8	78.9029	0.9481			NED
123.1	78.9031	0.9481		B=20.5, R2=19.2	SSS
123.5	78.9030	0.9482		B=21.3, R=19.2	APM-N
123.8	78.9279	0.9311			NED
123.9	78.9281	0.9312		B2=21.1, R1=19.2, R2=19.0	USNO-B1
125.4	78.9117	0.9464			NED
126.3	78.9146	0.9450			NED
126.5	78.8690	0.8946		B=19.3, R=18.7	APM-N
126.6	78.8691	0.8945		B=19.3, R2=18.6	SSS
127.0	78.9242	0.9383			NED
127.5	78.8704	0.8922			NED
127.6	78.9233	0.9392			NED
128.0	78.8671	0.8967			NED
128.1	78.9229	0.9397			NED
128.3	78.9204	0.8864			NED
128.5	78.9292	0.8967			NED
128.9	78.9150	0.9458			NED
130.6	78.9087	0.8794			NED
130.9	78.8875	0.9492			NED
131.5	78.9338	0.9222			NED
131.7	78.8863	0.8794			NED
132.1	78.8929	0.9505		B=21.4, R2=19.7	SSS
132.2	78.9167	0.9458			NED
132.4	78.9146	0.9469			NED
133.0	78.8929	0.9508			NED
133.1	78.9304	0.9322			NED
133.6	78.8987	0.8772			NED
133.8	78.8937	0.9511			NED
135.2	78.8917	0.9511			NED
135.7	78.8729	0.8864			NED
136.4	78.8804	0.8807		B=20.9, R=20.0	APM-N
137.5	78.9058	0.8767			NED
138.0	78.8925	0.8764			NED
138.1	78.9087	0.9511			NED
138.7	78.8842	0.9503			NED
139.3	78.8904	0.8764			NED
139.4	78.9192	0.9467			NED
139.6	78.9087	0.9514			NED
140.2	78.9079	0.9519			NED
140.4	78.8708	0.9422			NED
140.6	78.9171	0.9486			NED
141.6	78.9375	0.9167			NED
141.8	78.9242	0.8847			NED
142.9	78.8592	0.9064			NED
143.2	78.9092	0.9524		B=21.6, R2=20.1	SSS
143.5	78.9092	0.9525			NED
143.6	78.8590	0.9067		B=18.9, R=16.5	APM-N
145.1	78.9071	0.8749		B=20.2, R=19.4	APM-N
145.3	78.8925	0.9542			NED
146.5	78.9121	0.8758			NED
146.8	78.9363	0.9289			NED
146.9	78.9179	0.9500			NED
146.9	78.9071	0.9539			NED
147.1	78.9389	0.9180		B2=19.5, I=16.2, R1=17.3, R2=17.0	USNO-B1
147.2	78.8713	0.8833			NED
147.4	78.9387	0.9181			NED
147.9	78.9035	0.8735		B=22.2	SSS
148.1	78.8629	0.8928			NED
148.4	78.8646	0.9383			NED
148.8	78.9379	0.9253			NED
149.7	78.9204	0.9494			NED
149.7	78.9101	0.8743		B2=21.0, R2=20.3	USNO-B1
149.8	78.9153	0.8763		B=20.6, R=19.4	APM-N
149.9	78.9308	0.9400			NED
150.1	78.9229	0.9478			NED
150.8	78.9025	0.9558			NED
151.0	78.9350	0.8942			NED
151.2	78.9237	0.9475		B=17.9, R=16.8	APM-N
151.3	78.9237	0.9475			NED
151.3	78.9146	0.8756			NED
152.0	78.9242	0.9475			NED
152.0	78.8558	0.9111			NED
155.3	78.9412	0.9114			NED
156.2	78.8650	0.9422			NED
156.3	78.8975	0.8708			NED
156.9	78.9296	0.9444			NED
157.0	78.8696	0.8811			NED
157.3	78.8958	0.8706			NED
157.6	78.8958	0.8705		B=18.6, R2=17.7, i=17.5	SSS
157.6	78.8958	0.8705		B=19.1, R=17.3	APM-N
158.2	78.8558	0.9031			NED
159.2	78.8808	0.8736			NED
160.2	78.8554	0.9261			NED
160.3	78.9329	0.8861			NED
160.4	78.9267	0.8797			NED
161.1	78.8972	0.8695		B2=19.1, R1=18.7	USNO-B1
162.1	78.9133	0.9567			NED
162.2	78.8529	0.9161			NED
162.4	78.8531	0.9161		B2=20.7, I=16.4, R1=18.4, R2=18.7	USNO-B1
162.6	78.8977	0.8690		B2=20.9, R1=19.2, R2=20.1	USNO-B1
162.9	78.9336	0.8860		B1=20.9, R2=20.2	USNO-B1
162.9	78.9135	0.9568		B=22.6, R2=20.5	SSS
163.4	78.8675	0.9475			NED
163.5	78.8579	0.9350			NED
163.6	78.9299	0.9468		B=19.3, R2=17.9, i=17.0	SSS
163.7	78.9299	0.9468		B=19.6, R=17.4	APM-N
163.7	78.9300	0.9469			NED
163.7	78.9150	0.9564			NED
163.9	78.9146	0.8717			NED
166.2	78.9333	0.9439			NED
166.5	78.9329	0.9447			NED
167.8	78.9445	0.9197		B=21.1, R=20.0	APM-N
169.1	78.8950	0.8672			NED
169.4	78.8542	0.9308			NED
170.2	78.9450	0.9189			NED
170.2	78.9452	0.9189		B=20.0, R2=19.1, i=18.6	SSS
170.6	78.9453	0.9190		B=20.4, R=19.1	APM-N
170.7	78.9454	0.9187		B1=19.8, I=18.3, R1=18.2	USNO-B1
171.1	78.8558	0.8928			NED
172.1	78.8596	0.8861			NED
172.4	78.8593	0.8863		B=22.5	SSS
172.6	78.8506	0.9081		B=20.9, R=20.0	APM-N
172.7	78.8821	0.8689			NED
173.5	78.8504	0.9083			NED
173.8	78.9446	0.9008			NED
173.9	78.8503	0.9083		B1=20.0, B2=21.1	USNO-B1
173.9	78.8500	0.9083			NED
173.9	78.9100	0.8675			NED
174.5	78.8751	0.9568		B=21.2, R=20.0	APM-N
175.1	78.8808	0.9597			NED
175.1	78.8904	0.9622			NED
176.1	78.9038	0.8656			NED
176.6	78.9412	0.9372			NED
176.9	78.8713	0.8731			NED
177.9	78.9246	0.8725			NED
178.0	78.9467	0.9231			NED
178.7	78.8711	0.9558		B=21.2, R=20.0	APM-N
178.8	78.8517	0.9317			NED
179.3	78.8588	0.9450			NED
179.7	78.9421	0.8903			NED
180.7	78.9213	0.8697			NED
180.7	78.8979	0.8639			NED
183.8	78.8475	0.9078			NED
183.9	78.9471	0.9281			NED
184.0	78.9179	0.8669			NED
185.1	78.9387	0.8831			NED
185.1	78.9454	0.9344			NED
185.8	78.9467	0.8969			NED
186.1	78.8517	0.8916		B2=21.0, R1=19.3, R2=19.6	USNO-B1
186.2	78.9454	0.9353			NED
186.2	78.8683	0.8719			NED
186.4	78.9004	0.9658			NED
186.7	78.8542	0.8868		B=19.5, R=18.8	APM-N
187.0	78.9500	0.9101		B=21.1, R=20.0	APM-N
187.2	78.9450	0.9369			NED
187.2	78.8917	0.9658			NED
187.7	78.9183	0.8661			NED
188.5	78.8658	0.8731			NED
189.2	78.9017	0.8617			NED
190.4	78.9279	0.9581			NED
191.3	78.8967	0.9672			NED
191.3	78.8513	0.8889			NED
191.3	78.9508	0.9092			NED
191.7	78.8514	0.8888		B=18.2, R=17.1	APM-N
191.7	78.8762	0.8656			NED
192.5	78.8704	0.9600			NED
193.9	78.9521	0.9136			NED
194.0	78.8767	0.9636			NED
194.3	78.8768	0.9638		I=18.0, R1=19.4, R2=19.5	USNO-B1
194.5	78.8549	0.9465		B1=18.1, R2=17.1	USNO-B1
194.6	78.8629	0.8731			NED
194.7	78.9450	0.8869			NED
194.8	78.8671	0.9586			NED
196.0	78.8567	0.8789			NED
196.2	78.9350	0.8742			NED
196.4	78.8942	0.9686			NED
196.6	78.8688	0.9603			NED
197.0	78.8732	0.8655		B=22.0	SSS
197.5	78.9350	0.9547			NED
197.6	78.8433	0.9175			NED
198.1	78.8783	0.8628			NED
198.7	78.8471	0.8933		B=22.6	SSS
199.6	78.9504	0.8953			NED
199.9	78.8450	0.8983			NED

Queried APM-N, SDSS, PSCz, SSS, NED, 2MASSX, USNO-B1.

* RA/Dec in equinox J2000

Magnitudes depend on the catalogue. e.g. For Sloan, R is the Sloan r mag, not the Johnson R from APM, for example