Swift Trigger: 1037339;

Presumed name: GRB 210318A

BAT	02^h 15^m 43.20^s, -37° 47′ 20.4″
position:	(33.930, -37.789 ± 180″)
XRT	02^h 15^m 42.31^s, -37° 46′ 37.9″
position:	(33.9263, -37.7772 ± 3.2″)
UVOT	No position available.
Galactic N_HI:	1.79×10⁰ cm^-2
Galactic E(B-V):	0.016 mag

Best RA:	02^h 15^m 42.31^s	= 33.9263 d
Best Dec:	-37° 46′ 37.9″	= -37.7772 d

Gal Lat:	-69.35
Gal Long:	249.25

Sun angle:	49.61°, -2.4 hr East of Sun

¹Sper #2 auto processing.

Galaxies within 3.33 of XRT position

	RA*	Dec*		Catalogue
23.7	33.9179	-37.7781		NED
27.1	33.9279	-37.7847		NED
29.5	33.9329	-37.7836	Mag=19.5	NED
29.8	33.9247	-37.7854	B2=23.2, R2=25.0	USNO-B1
30.1	33.9216	-37.7847	B=21.8	SSS
36.3	33.9379	-37.7811	Mag=19.5	NED
37.8	33.9389	-37.7807	B=19.9, R2=18.4, i=18.0	SSS
42.7	33.9360	-37.7862	B=21.8, R2=19.2, i=18.7	SSS
42.8	33.9292	-37.7656	Mag=19.5	NED
43.0	33.9183	-37.7669	Mag=19.5	NED
43.0	33.9362	-37.7862	B2=20.8, I=18.4, R1=20.1, R2=20.4	USNO-B1
43.0	33.9363	-37.7861	Mag=19.4	NED
45.2	33.9413	-37.7733	Mag=19.4	NED
52.1	33.9421	-37.7844	Mag=19.4	NED
54.3	33.9437	-37.7831	Mag=19.79	NED
56.4	33.9221	-37.7619	Mag=19.79	NED
58.9	33.9067	-37.7722	Mag=19.1	NED
59.3	33.9054	-37.7789	Mag=19.1	NED
59.8	33.9275	-37.7606	Mag=19.1	NED
61.4	33.9467	-37.7825	Mag=19.1	NED
62.5	33.9354	-37.7614	Mag=19.1	NED
63.2	33.9396	-37.7633	Mag=19.1	NED
65.2	33.9375	-37.7928	Mag=19.1	NED
65.8	33.9421	-37.7903	Mag=18.2	NED
65.9	33.9421	-37.7905	B=19.1, R2=17.8, i=17.8	SSS
69.2	33.9141	-37.7938	B=21.8	SSS
70.8	33.9512	-37.7761	B=22.2	SSS
72.9	33.9208	-37.7575	Mag=18.2	NED
75.4	33.9117	-37.7947	Mag=18.2	NED
75.7	33.9113	-37.7946	B=21.0, R2=19.9, i=19.1	SSS
77.8	33.9237	-37.7556	Mag=18.2	NED
79.5	33.9127	-37.7965	B2=23.5, I=18.3, R2=23.7	USNO-B1
81.0	33.8983	-37.7815	B2=21.3, R2=24.3	USNO-B1
81.1	33.9158	-37.7561	Mag=20.38	NED
81.2	33.8983	-37.7814	Mag=20.38	NED
82.4	33.9471	-37.7931	Mag=19.04	NED
83.5	33.8971	-37.7761	Mag=19.04	NED
85.7	33.9171	-37.7544	Mag=19.04	NED
86.4	33.9500	-37.7619	Mag=19.04	NED
86.7	33.9467	-37.7593	B=22.1	SSS
86.9	33.9546	-37.7858	Mag=19.04	NED
88.3	33.9571	-37.7758	Mag=19.04	NED
88.7	33.9071	-37.7578	Mag=19.04	NED
89.0	33.9067	-37.7580	B=22.0, R2=21.1	SSS
89.6	33.9571	-37.7717	Mag=19.04	NED
90.4	33.8950	-37.7728	Mag=19.04	NED
91.1	33.9583	-37.7792	Mag=19.04	NED
91.9	33.9329	-37.7522	Mag=19.04	NED
92.3	33.9583	-37.7817	Mag=19.04	NED
94.7	33.9109	-37.7539	B=20.6, R2=18.3, i=18.1	SSS
94.9	33.9108	-37.7539	Mag=19.04	NED
97.9	33.8917	-37.7772	Mag=19.04	NED
99.4	33.8929	-37.7694	Mag=19.04	NED
99.7	33.9350	-37.8042	Mag=19.04	NED
100.5	33.9596	-37.7678	Mag=19.04	NED
101.2	33.9154	-37.7503	Mag=20.20	NED
103.8	33.8909	-37.7840	B=21.8	SSS
103.8	33.8908	-37.7838	B2=23.5, R2=21.1	USNO-B1
104.0	33.9621	-37.7828	Mag=20.20	NED
107.6	33.9194	-37.8066	B2=23.1, I=18.7, R2=24.7	USNO-B1
110.0	33.9350	-37.7475	Mag=20.20	NED
111.0	33.9496	-37.7525	Mag=20.20	NED
112.0	33.9200	-37.8078	Mag=20.20	NED
112.2	33.9039	-37.8029	B=22.3	SSS
112.7	33.8874	-37.7832	B=21.6	SSS
113.1	33.8871	-37.7833	Mag=20.20	NED
113.9	33.9108	-37.7480	B2=21.0, R1=19.7, R2=20.0	USNO-B1
114.4	33.9404	-37.8069	Mag=20.20	NED
114.4	33.9105	-37.7480	B2=20.8, I=18.6	USNO-B1
114.8	33.9100	-37.7480	B=21.0, R2=18.4, i=18.0	SSS
115.2	33.9104	-37.7478	Mag=18.7	NED
116.4	33.9167	-37.7458	Mag=18.7	NED
116.6	33.8937	-37.7575	B=21.6	SSS
118.7	33.9675	-37.7814	Mag=18.7	NED
119.0	33.8958	-37.7997	Mag=18.7	NED
119.0	33.9496	-37.7497	Mag=18.7	NED
119.2	33.9342	-37.8097	Mag=18.7	NED
119.5	33.9288	-37.8103	Mag=18.7	NED
120.5	33.9625	-37.7597	Mag=18.7	NED
120.6	33.9625	-37.7597	B=20.4, R2=18.5, i=18.2	SSS
122.0	33.9408	-37.7453	Mag=18.7	NED
124.3	33.8858	-37.7900	Mag=18.7	NED
124.5	33.9212	-37.8115	B2=21.4, R1=20.3, R2=23.6	USNO-B1
124.6	33.8888	-37.7950	Mag=18.7	NED
125.9	33.9213	-37.8119	Mag=18.7	NED
125.9	33.8883	-37.7951	B2=23.3, I=18.6, R1=20.2, R2=24.1	USNO-B1
126.0	33.9267	-37.7422	B=22.6	SSS
126.0	33.9213	-37.8120	B=21.2, R2=19.8	SSS
129.3	33.9375	-37.8119	Mag=18.7	NED
129.5	33.9675	-37.7622	Mag=20.19	NED
130.7	33.9100	-37.8111	Mag=20.19	NED
131.3	33.9454	-37.8103	Mag=20.19	NED
132.3	33.9308	-37.7406	Mag=20.19	NED
132.5	33.8800	-37.7819	Mag=20.19	NED
133.4	33.9325	-37.8139	Mag=20.19	NED
134.0	33.9617	-37.8017	Mag=20.19	NED
134.2	33.9371	-37.7408	Mag=20.19	NED
134.2	33.8800	-37.7697	Mag=20.19	NED
134.4	33.9734	-37.7747	B=22.0	SSS
134.5	33.8804	-37.7867	Mag=20.19	NED
134.8	33.8791	-37.7798	B=21.4	SSS
135.0	33.9133	-37.7411	Mag=18.2	NED
135.1	33.8798	-37.7698	B2=19.0, I=15.8, R1=15.2, R2=15.2	USNO-B1
135.1	33.8798	-37.7697	B=18.2, R2=15.7, i=15.2	SSS
135.4	33.9132	-37.7411	B=20.6, R2=18.1, i=17.6	SSS
136.2	33.8875	-37.7994	Mag=18.2	NED
136.4	33.9730	-37.7685	B2=20.5, I=18.6, R1=19.7, R2=20.6	USNO-B1
136.5	33.8938	-37.7494	Mag=18.2	NED
136.8	33.9731	-37.7686	B=21.0, R2=19.1, i=19.2	SSS
137.2	33.9733	-37.7683	Mag=19.4	NED
139.9	33.8979	-37.7456	Mag=19.4	NED
142.5	33.9283	-37.7378	Mag=19.4	NED
142.8	33.9575	-37.8081	Mag=19.4	NED
143.5	33.9246	-37.7372	Mag=19.4	NED
143.8	33.9742	-37.7900	Mag=19.4	NED
144.1	33.9767	-37.7786	Mag=19.4	NED
144.1	33.9525	-37.7431	Mag=19.4	NED
145.0	33.9721	-37.7594	Mag=19.4	NED
145.1	33.9471	-37.8139	Mag=19.4	NED
145.6	33.9775	-37.7758	Mag=19.4	NED
145.8	33.9648	-37.7504	B=20.7, R2=18.8, i=18.3	SSS
146.2	33.9646	-37.7503	Mag=19.4	NED
146.8	33.8835	-37.7544	B=21.8	SSS
147.4	33.9655	-37.7505	B2=20.6, I=18.7	USNO-B1
148.5	33.9000	-37.8131	Mag=19.4	NED
149.5	33.8938	-37.8100	Mag=19.4	NED
150.8	33.8733	-37.7742	Mag=19.4	NED
152.4	33.9079	-37.7375	Mag=19.4	NED
153.2	33.9008	-37.7397	Mag=19.4	NED
153.3	33.9392	-37.7358	Mag=19.4	NED
154.1	33.9554	-37.8133	Mag=19.4	NED
154.4	33.9300	-37.8200	Mag=19.4	NED
154.5	33.9693	-37.7509	B2=21.4, R2=23.6	USNO-B1
154.6	33.9694	-37.7511	B=21.1, R2=19.4, i=19.5	SSS
154.6	33.9692	-37.7508	Mag=19.4	NED
154.7	33.9301	-37.8201	B=21.3, R2=19.7, i=19.1	SSS
154.8	33.9250	-37.7342	Mag=19.4	NED
156.0	33.9704	-37.8028	Mag=19.4	NED
160.0	33.8871	-37.7453	Mag=19.4	NED
160.7	33.9371	-37.7333	Mag=19.4	NED
161.8	33.9008	-37.7369	Mag=19.4	NED
162.1	33.9129	-37.8211	Mag=19.4	NED
162.4	33.8754	-37.7978	Mag=19.4	NED
162.8	33.9017	-37.8181	Mag=18.03	NED
162.9	33.9018	-37.8181	B2=18.8, I=15.4, R1=14.4, R2=14.5	USNO-B1
163.0	33.9017	-37.8181	B=18.2, R2=16.2, i=16.1	SSS
163.2	33.9018	-37.8182	h=14.2, j=14.9, k=13.7	2MASS
164.1	33.8696	-37.7690	B=21.4	SSS
164.2	33.9592	-37.8147	Mag=18.03	NED
164.7	33.9593	-37.8148	B=20.5, R2=18.9, i=18.9	SSS
164.8	33.9594	-37.8148	B2=21.0, I=18.7, R2=19.8	USNO-B1
165.2	33.9542	-37.8175	Mag=18.03	NED
165.8	33.8871	-37.8114	Mag=18.03	NED
166.4	33.9237	-37.8233	Mag=18.03	NED
166.9	33.9850	-37.7767	Mag=18.03	NED
167.3	33.9850	-37.7800	Mag=18.03	NED
168.2	33.8929	-37.7386	Mag=18.03	NED
168.7	33.9850	-37.7831	Mag=18.03	NED
169.0	33.9800	-37.7575	Mag=18.03	NED
169.5	33.9846	-37.7869	Mag=18.03	NED
169.7	33.9333	-37.8239	Mag=18.03	NED
170.0	33.9848	-37.7869	B=22.1, R2=20.5, i=19.5	SSS
170.8	33.9662	-37.7419	Mag=18.03	NED
171.2	33.9375	-37.8239	Mag=18.03	NED
172.5	33.9741	-37.7477	B=22.2	SSS
172.6	33.9742	-37.7478	Mag=18.03	NED
174.6	33.8696	-37.7958	Mag=18.03	NED
175.0	33.9525	-37.8211	Mag=18.03	NED
176.3	33.8971	-37.8206	Mag=18.03	NED
176.6	33.8971	-37.8206	Mag=18.03	NED
178.9	33.9492	-37.7311	Mag=18.03	NED
180.5	33.9642	-37.8172	Mag=20.37	NED
182.2	33.8892	-37.8183	Mag=20.41	NED
183.1	33.9483	-37.8250	Mag=20.41	NED
183.5	33.8625	-37.7689	Mag=19.0	NED
183.7	33.9396	-37.7272	Mag=19.0	NED
184.0	33.9446	-37.8261	Mag=19.0	NED
184.3	33.9758	-37.7444	Mag=19.0	NED
184.6	33.8837	-37.8161	Mag=19.0	NED
184.6	33.8775	-37.7433	Mag=19.0	NED
184.6	33.8840	-37.8161	B=20.6, R2=18.7, i=17.9	SSS
184.8	33.9816	-37.7503	B=22.2, R2=20.4	SSS
185.0	33.8621	-37.7688	B2=21.4, I=18.5	USNO-B1
185.3	33.8708	-37.8042	Mag=19.0	NED
185.3	33.9914	-37.7766	B2=23.1, R2=25.0	USNO-B1
185.8	33.8708	-37.8044	B=19.9, R2=17.9, i=17.5	SSS
186.0	33.8696	-37.7516	B=21.9	SSS
186.2	33.9537	-37.7303	Mag=19.0	NED
186.3	33.9536	-37.7302	B=21.3, R2=19.5, i=18.8	SSS
187.6	33.9704	-37.8158	Mag=19.0	NED
187.9	33.9875	-37.7581	Mag=19.0	NED
188.5	33.9696	-37.7375	Mag=19.0	NED
188.6	33.8604	-37.7722	Mag=19.0	NED
189.0	33.9804	-37.7469	Mag=19.0	NED
189.1	33.9654	-37.7347	Mag=19.0	NED
189.5	33.9925	-37.7808	Mag=19.0	NED
190.6	33.9193	-37.7245	B=20.8, R2=18.8, i=18.5	SSS
190.8	33.9192	-37.7244	Mag=19.0	NED
192.9	33.8650	-37.7542	Mag=19.0	NED
193.3	33.9662	-37.8206	Mag=19.0	NED
193.4	33.8833	-37.7356	Mag=19.0	NED
194.5	33.9796	-37.7436	Mag=19.0	NED
195.0	33.8641	-37.7545	I=18.1, R2=20.7	USNO-B1
195.1	33.9775	-37.7411	Mag=19.0	NED
195.2	33.9521	-37.7269	Mag=19.0	NED
195.2	33.9950	-37.7775	Mag=19.0	NED
195.5	33.9700	-37.8192	Mag=19.0	NED
195.7	33.9942	-37.7853	Mag=19.0	NED
196.2	33.9779	-37.7411	B=21.7	SSS
196.3	33.9846	-37.7481	Mag=19.0	NED
196.4	33.9942	-37.7675	Mag=19.0	NED
196.7	33.8604	-37.7939	Mag=19.0	NED
197.0	33.9663	-37.8218	B=22.5, R2=21.2	SSS
197.0	33.9129	-37.8308	Mag=19.0	NED
198.5	33.8771	-37.7381	Mag=19.0	NED
198.5	33.9333	-37.8319	Mag=19.0	NED
198.8	33.8796	-37.8183	B=22.5	SSS
199.7	33.9596	-37.7283	B=22.5	SSS

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