Swift-XRT Survey of Fermi Unassociated Sources

These results are part of the Swift program to follow-up Fermi unassociated sources in an attempt to find X-ray counterparts to the unidentified gamma-ray sources. As new observations are performed, these pages will be updated in nearly real time. Please use these results as a guide and proceed with caution when using them in a publication since they are the result of an automated analysis.

When using these data and results in publications, please reference M.C. Stroh & A.D. Falcone 2013, ApJS, 207, 28; arXiv: 1305.4949 for a description of many of the analysis techniques used to reduce these data (note: a more detailed paper describing the complete data set and analysis is forthcoming). Please contact Abe Falcone and Michael Stroh at unassociated@swift.psu.edu if you have any questions about the program or the analysis, or to simply to let us know that you've made use of these data.
Caution: For completeness, sources are listed if the "detection" exceeds 3 sigma. The significances and images are shown so you can make more stringent significance cuts, if desired.

4FGL J1731.7-1850

Field

Detected Excesses
Swift-XRT image of the field for 4FGL J1731.7-1850 Swift-XRT detections in the field for 4FGL J1731.7-1850

Detected Excesses (SNR(Sosta) > 3.0)

# R.A. (J2000) Dec. (J2000) Pos. Error (") Rate (cts/s) Counts SNR (Detect) SNR (Sosta)
1 17 32 23.64 -18 50 26.70 4.88 (5.4 ± 0.9) x 10-2 46 6.870 6.387

Rejected Excesses (Due to Overlaps or SNR(Sosta) < 3.0)

# R.A. (J2000) Dec. (J2000) Pos. Error (") Rate (cts/s) Counts SNR (Detect) SNR (Sosta)
1 17 31 33.05 -18 49 50.82 9.56 (7 ± 3) x 10-3 7 2.195 2.146

X-Ray and Gamma Ray Catalogs

More Catalogs
Swift-XRT image with known X-ray and gamma ray sources for 4FGL J1731.7-1850 Swift-XRT image with known radio, optical and UV sources for 4FGL J1731.7-1850

Known X-Ray and Gamma Ray Sources

# Source Name R.A. (J2000) Dec. (J2000) Offset (') Observatory/Database Table
4XMMs J173144.3-184931 17 31 44.35 -18 49 31.08 0.74 XMM-NEWTON
1 2CXO J173144.3-184926 17 31 44.35 -18 49 26.40 0.80 CHANDRA
2 4XMM J173138.8-185020 17 31 38.88 -18 50 20.76 0.83 XMM-NEWTON
4XMMs J173138.8-185021 17 31 38.81 -18 50 21.84 0.85 XMM-NEWTON
3 2CXO J173138.2-184846 17 31 38.28 -18 48 46.08 1.58 CHANDRA
4XMM J173138.2-184846 17 31 38.23 -18 48 46.80 1.58 XMM-NEWTON
4XMMs J173138.2-184845 17 31 38.23 -18 48 45.72 1.59 XMM-NEWTON
CXOGSG J173138.2-184844 17 31 38.28 -18 48 44.64 1.60 CHANDRA
4 2CXO J173135.4-184938 17 31 35.45 -18 49 38.28 1.65 CHANDRA
5 2CXO J173132.7-184948 17 31 32.76 -18 49 48.36 2.24 CHANDRA
4XMM J173132.7-184950 17 31 32.76 -18 49 50.16 2.24 XMM-NEWTON
CXOGSG J173132.7-184948 17 31 32.76 -18 49 48.36 2.24 CHANDRA
4XMMs J173132.7-184950 17 31 32.74 -18 49 50.16 2.24 XMM-NEWTON
6 2CXO J173151.2-185154 17 31 51.26 -18 51 54.72 2.85 CHANDRA
7 4XMMs J173151.6-185247 17 31 51.65 -18 52 47.28 3.54 XMM-NEWTON
8 4XMM J173137.4-184641 17 31 37.42 -18 46 41.52 3.54 XMM-NEWTON
4XMMs J173137.4-184641 17 31 37.42 -18 46 41.16 3.55 XMM-NEWTON
4XMM J173151.6-185249 17 31 51.60 -18 52 49.80 3.56 XMM-NEWTON
9 4XMMs J173157.5-184940 17 31 57.60 -18 49 40.44 3.67 XMM-NEWTON
4XMM J173157.5-184939 17 31 57.60 -18 49 39.72 3.67 XMM-NEWTON
10 2CXO J173131.2-184715 17 31 31.27 -18 47 15.36 3.80 CHANDRA
CXOGSG J173131.2-184715 17 31 31.27 -18 47 15.00 3.81 CHANDRA
11 4XMMs J173148.0-185345 17 31 48.05 -18 53 45.96 3.96 XMM-NEWTON
12 4XMMs J173123.4-185002 17 31 23.40 -18 50 02.76 4.44 XMM-NEWTON
13 2CXO J173138.1-185436 17 31 38.11 -18 54 36.72 4.66 CHANDRA
4XMM J173138.0-185437 17 31 38.04 -18 54 37.08 4.67 XMM-NEWTON
4XMMs J173138.2-185438 17 31 38.21 -18 54 38.52 4.68 XMM-NEWTON
14 4XMM J173144.8-184521 17 31 44.83 -18 45 21.24 4.74 XMM-NEWTON
4XMMs J173144.6-184518 17 31 44.66 -18 45 18.72 4.78 XMM-NEWTON
15 2CXO J173149.5-185430 17 31 49.56 -18 54 30.96 4.79 CHANDRA
4XMM J173149.5-185431 17 31 49.51 -18 54 32.04 4.81 XMM-NEWTON
4XMMs J173149.5-185432 17 31 49.54 -18 54 32.04 4.81 XMM-NEWTON
16 2CXO J173128.4-185353 17 31 28.44 -18 53 53.88 5.03 CHANDRA
4XMM J173128.4-185356 17 31 28.46 -18 53 56.40 5.06 XMM-NEWTON
4XMMs J173128.4-185356 17 31 28.42 -18 53 56.40 5.07 XMM-NEWTON
17 4XMM J173139.4-184447 17 31 39.48 -18 44 48.12 5.29 XMM-NEWTON
18 4XMMs J173204.3-184922 17 32 04.37 -18 49 22.08 5.30 XMM-NEWTON
4XMM J173204.3-184921 17 32 04.39 -18 49 22.08 5.30 XMM-NEWTON
4XMMs J173139.2-184446 17 31 39.24 -18 44 46.68 5.32 XMM-NEWTON
4XMM J173143.8-184438 17 31 43.82 -18 44 38.40 5.43 XMM-NEWTON
4XMMs J173143.8-184438 17 31 43.82 -18 44 38.04 5.43 XMM-NEWTON
19 2CXO J173143.7-184437 17 31 43.75 -18 44 37.68 5.44 CHANDRA
20 2CXO J173120.1-185200 17 31 20.16 -18 52 00.12 5.56 CHANDRA
CXOGSG J173120.1-185200 17 31 20.16 -18 52 00.12 5.56 CHANDRA
4XMM J173120.2-185202 17 31 20.21 -18 52 02.28 5.56 XMM-NEWTON
4XMMs J173120.2-185202 17 31 20.21 -18 52 01.92 5.56 XMM-NEWTON
4XMM J173137.1-184427 17 31 37.20 -18 44 27.60 5.72 XMM-NEWTON
4XMMs J173137.1-184427 17 31 37.18 -18 44 27.60 5.72 XMM-NEWTON
21 CXOGSG J173137.3-184425 17 31 37.37 -18 44 25.80 5.74 CHANDRA
2CXO J173137.3-184425 17 31 37.34 -18 44 25.44 5.74 CHANDRA
4XMM J173145.4-184355 17 31 45.46 -18 43 55.92 6.17 XMM-NEWTON
22 2CXO J173145.1-184354 17 31 45.14 -18 43 54.12 6.19 CHANDRA
4XMMs J173145.0-184353 17 31 45.02 -18 43 53.40 6.20 XMM-NEWTON
23 4XMM J173146.9-185613 17 31 46.97 -18 56 13.20 6.27 XMM-NEWTON
4XMMs J173146.9-185614 17 31 46.97 -18 56 14.28 6.29 XMM-NEWTON
4XMM J173117.6-184733 17 31 17.62 -18 47 33.72 6.32 XMM-NEWTON
4XMMs J173117.5-184733 17 31 17.59 -18 47 33.72 6.33 XMM-NEWTON
24 CXOGSG J173117.5-184733 17 31 17.59 -18 47 33.00 6.33 CHANDRA
2CXO J173117.5-184732 17 31 17.59 -18 47 32.64 6.33 CHANDRA
25 4XMM J173125.0-184507 17 31 25.08 -18 45 07.56 6.37 XMM-NEWTON
4XMMs J173124.9-184507 17 31 24.94 -18 45 07.56 6.40 XMM-NEWTON
26 4XMM J173156.6-184435 17 31 56.59 -18 44 35.16 6.45 XMM-NEWTON
4XMMs J173156.7-184434 17 31 56.71 -18 44 34.44 6.47 XMM-NEWTON
4XMMs J173114.2-184854 17 31 14.26 -18 48 54.72 6.70 XMM-NEWTON
27 CXOGSG J173114.2-184851 17 31 14.28 -18 48 51.48 6.70 CHANDRA
2CXO J173114.2-184851 17 31 14.28 -18 48 51.48 6.70 CHANDRA
4XMM J173114.2-184854 17 31 14.23 -18 48 54.36 6.71 XMM-NEWTON
28 4XMM J173116.8-184700 17 31 16.80 -18 47 00.24 6.73 XMM-NEWTON
4XMMs J173116.8-184658 17 31 16.80 -18 46 58.80 6.74 XMM-NEWTON
29 4XMM J173212.0-185038 17 32 12.02 -18 50 38.40 7.09 XMM-NEWTON
4XMMs J173212.0-185038 17 32 12.07 -18 50 38.04 7.10 XMM-NEWTON
30 4XMMs J173118.1-185422 17 31 18.17 -18 54 22.32 7.14 XMM-NEWTON
31 4XMMs J173116.7-184605 17 31 16.75 -18 46 05.52 7.20 XMM-NEWTON
4XMM J173116.6-184605 17 31 16.66 -18 46 05.88 7.22 XMM-NEWTON
32 CXOGSG J173111.6-184958 17 31 11.62 -18 49 58.80 7.23 CHANDRA
2CXO J173111.6-184958 17 31 11.59 -18 49 58.80 7.23 CHANDRA
4XMM J173111.4-185001 17 31 11.47 -18 50 01.68 7.26 XMM-NEWTON
33 4XMM J173212.8-184912 17 32 12.89 -18 49 12.00 7.32 XMM-NEWTON
4XMMs J173212.8-184912 17 32 12.89 -18 49 12.00 7.32 XMM-NEWTON
34 4XMM J173213.1-185143 17 32 13.10 -18 51 43.56 7.51 XMM-NEWTON
4XMMs J173213.1-185143 17 32 13.15 -18 51 43.56 7.52 XMM-NEWTON
2CXO J173110.3-185007 17 31 10.34 -18 50 07.44 7.53 CHANDRA
CXOGSG J173110.3-185007 17 31 10.32 -18 50 07.08 7.54 CHANDRA
4XMMs J173109.9-185001 17 31 09.91 -18 50 00.96 7.63 XMM-NEWTON
35 4XMM J173125.2-184324 17 31 25.27 -18 43 24.96 7.75 XMM-NEWTON
36 4XMM J173136.4-185741 17 31 36.43 -18 57 41.40 7.76 XMM-NEWTON
4XMMs J173125.2-184324 17 31 25.27 -18 43 24.60 7.76 XMM-NEWTON
4XMMs J173136.3-185741 17 31 36.36 -18 57 41.76 7.77 XMM-NEWTON
4XMM J173109.3-184958 17 31 09.31 -18 49 58.44 7.78 XMM-NEWTON
37 2CXO J173108.9-184956 17 31 09.00 -18 49 56.28 7.85 CHANDRA
38 CXOGSG J173110.1-184741 17 31 10.20 -18 47 41.64 7.93 CHANDRA
2CXO J173110.1-184741 17 31 10.18 -18 47 41.64 7.93 CHANDRA
4XMMs J173109.8-184752 17 31 09.86 -18 47 52.80 7.95 XMM-NEWTON
4XMM J173109.8-184752 17 31 09.86 -18 47 52.80 7.95 XMM-NEWTON
CXOGSG J173109.8-184750 17 31 09.84 -18 47 50.28 7.96 CHANDRA
2CXO J173109.8-184750 17 31 09.84 -18 47 50.64 7.96 CHANDRA
39 4XMM J173140.4-185819 17 31 40.49 -18 58 19.20 8.28 XMM-NEWTON
4XMMs J173140.5-185820 17 31 40.56 -18 58 20.28 8.29 XMM-NEWTON
40 CXOGSG J173106.6-184949 17 31 06.67 -18 49 49.44 8.41 CHANDRA
2CXO J173106.6-184949 17 31 06.62 -18 49 49.80 8.41 CHANDRA
4XMMs J173106.6-184951 17 31 06.60 -18 49 51.60 8.42 XMM-NEWTON
4XMM J173106.5-184952 17 31 06.60 -18 49 53.04 8.42 XMM-NEWTON
41 4XMM J173132.9-185811 17 31 32.98 -18 58 11.64 8.43 XMM-NEWTON
42 4XMM J173136.4-185823 17 31 36.41 -18 58 23.88 8.46 XMM-NEWTON
4XMMs J173136.4-185824 17 31 36.46 -18 58 24.24 8.46 XMM-NEWTON
43 4XMMs J173211.7-184459 17 32 11.76 -18 44 59.28 8.64 XMM-NEWTON
4XMM J173211.7-184457 17 32 11.71 -18 44 57.84 8.65 XMM-NEWTON
44 2CXO J173105.4-184855 17 31 05.40 -18 48 55.44 8.77 CHANDRA
CXOGSG J173105.4-184855 17 31 05.40 -18 48 55.08 8.77 CHANDRA
4XMM J173105.3-184859 17 31 05.35 -18 48 59.40 8.78 XMM-NEWTON
4XMMs J173105.3-184900 17 31 05.33 -18 49 00.12 8.78 XMM-NEWTON
4XMMs J173128.6-184149 17 31 28.63 -18 41 49.56 8.83 XMM-NEWTON
45 2CXO J173128.9-184147 17 31 28.90 -18 41 47.76 8.83 CHANDRA
4XMM J173128.5-184149 17 31 28.56 -18 41 49.56 8.84 XMM-NEWTON
46 2CXO J173105.4-184800 17 31 05.47 -18 48 00.00 8.92 CHANDRA
47 4XMMs J173144.0-185907 17 31 44.04 -18 59 07.44 9.08 XMM-NEWTON
4XMM J173143.9-185907 17 31 43.97 -18 59 07.80 9.09 XMM-NEWTON
48 4XMMs J173105.9-184700 17 31 05.95 -18 47 00.60 9.10 XMM-NEWTON
4XMM J173105.8-184700 17 31 05.88 -18 47 00.24 9.11 XMM-NEWTON
4XMM J173143.4-184056 17 31 43.42 -18 40 56.28 9.12 XMM-NEWTON
4XMMs J173143.4-184056 17 31 43.44 -18 40 56.28 9.12 XMM-NEWTON
49 2CXO J173143.6-184054 17 31 43.68 -18 40 54.48 9.15 CHANDRA
CXOGSG J173143.7-184054 17 31 43.73 -18 40 54.48 9.15 CHANDRA
50 CXOGSG J173104.4-185239 17 31 04.44 -18 52 40.08 9.30 CHANDRA
4XMMs J173104.4-185243 17 31 04.49 -18 52 43.68 9.31 XMM-NEWTON
2CXO J173104.4-185240 17 31 04.42 -18 52 40.08 9.31 CHANDRA
4XMM J173104.4-185243 17 31 04.49 -18 52 43.32 9.31 XMM-NEWTON
51 4XMM J173121.7-185816 17 31 21.70 -18 58 16.32 9.54 XMM-NEWTON
TYC 6243-170-1 17 32 22.99 -18 50 30.12 9.67 ROSAT
52 4XMMs J173101.3-185053 17 31 01.32 -18 50 53.16 9.70 XMM-NEWTON
4XMM J173107.7-184446 17 31 07.73 -18 44 46.68 9.71 XMM-NEWTON
4XMMs J173107.7-184446 17 31 07.73 -18 44 46.68 9.71 XMM-NEWTON
4XMM J173101.2-185054 17 31 01.27 -18 50 54.24 9.72 XMM-NEWTON
53 CXOGSG J173107.8-184443 17 31 07.82 -18 44 43.44 9.72 CHANDRA
2CXO J173107.8-184443 17 31 07.82 -18 44 43.44 9.72 CHANDRA
4XMM J173101.9-184747 17 31 01.92 -18 47 47.40 9.79 XMM-NEWTON
54 2CXO J173101.9-184743 17 31 01.92 -18 47 43.44 9.81 CHANDRA
4XMMs J173101.8-184746 17 31 01.82 -18 47 46.68 9.81 XMM-NEWTON
55 4XMM J173108.0-185540 17 31 08.04 -18 55 40.44 9.84 XMM-NEWTON
4XMMs J173107.9-185540 17 31 07.99 -18 55 40.44 9.85 XMM-NEWTON
56 XMMSL2 J173224.0-185023 17 32 23.88 -18 50 23.28 9.88 XMM-NEWTON
2RXS J173223.8-185035 17 32 23.88 -18 50 35.88 9.89 ROSAT
1RXS J173223.9-185036 17 32 23.90 -18 50 35.88 9.89 ROSAT
1RXS J173223.9-185036 17 32 23.90 -18 50 36.60 9.89 ROSAT
57 4XMM J173100.6-185137 17 31 00.65 -18 51 37.44 9.95 XMM-NEWTON
4XMMs J173100.6-185139 17 31 00.67 -18 51 39.96 9.95 XMM-NEWTON
58 CXOGSG J173102.6-184639 17 31 02.64 -18 46 39.36 9.96 CHANDRA
4XMM J173102.5-184643 17 31 02.52 -18 46 43.68 9.96 XMM-NEWTON
2CXO J173102.6-184638 17 31 02.64 -18 46 39.00 9.96 CHANDRA
4XMMs J173102.5-184643 17 31 02.50 -18 46 42.96 9.96 XMM-NEWTON
59 4XMM J173113.3-185807 17 31 13.39 -18 58 07.32 10.56 XMM-NEWTON
4XMMs J173113.3-185807 17 31 13.37 -18 58 07.68 10.57 XMM-NEWTON
60 4XMMs J173101.3-184503 17 31 01.32 -18 45 03.96 10.88 XMM-NEWTON
61 4XMMs J173220.3-184352 17 32 20.38 -18 43 53.04 10.95 XMM-NEWTON
62 2CXO J173100.4-185457 17 31 00.48 -18 54 57.24 11.01 CHANDRA
4XMM J173100.5-185501 17 31 00.58 -18 55 01.56 11.02 XMM-NEWTON
4XMMs J173100.5-185501 17 31 00.58 -18 55 01.56 11.03 XMM-NEWTON
CXOGSG J173100.3-185455 17 31 00.34 -18 54 55.80 11.03 CHANDRA
4XMMs J173056.9-184655 17 30 56.95 -18 46 55.92 11.15 XMM-NEWTON
63 CXOGSG J173057.0-184652 17 30 57.02 -18 46 51.96 11.15 CHANDRA
2CXO J173057.0-184651 17 30 57.00 -18 46 51.60 11.15 CHANDRA
4XMM J173056.8-184655 17 30 56.88 -18 46 55.56 11.16 XMM-NEWTON
64 CXOGSG J173056.0-185303 17 30 56.02 -18 53 03.12 11.32 CHANDRA
2CXO J173056.0-185304 17 30 56.04 -18 53 04.20 11.32 CHANDRA
4XMMs J173056.0-185307 17 30 56.02 -18 53 07.44 11.34 XMM-NEWTON
4XMM J173055.9-185307 17 30 55.99 -18 53 07.80 11.35 XMM-NEWTON
65 CXOGSG J173114.6-184033 17 31 14.64 -18 40 33.60 11.51 CHANDRA
2CXO J173114.6-184032 17 31 14.69 -18 40 32.16 11.52 CHANDRA
4XMM J173114.4-184034 17 31 14.45 -18 40 34.68 11.53 XMM-NEWTON
4XMMs J173114.4-184034 17 31 14.42 -18 40 33.96 11.54 XMM-NEWTON
66 4XMM J173122.8-183927 17 31 22.87 -18 39 27.00 11.55 XMM-NEWTON
4XMMs J173122.7-183927 17 31 22.80 -18 39 27.36 11.55 XMM-NEWTON
67 4XMM J173215.1-184118 17 32 15.14 -18 41 18.60 11.72 XMM-NEWTON
4XMMs J173215.2-184119 17 32 15.29 -18 41 19.68 11.73 XMM-NEWTON
68 4XMMs J173055.8-185453 17 30 55.80 -18 54 53.64 11.99 XMM-NEWTON
4XMM J173055.8-185454 17 30 55.80 -18 54 54.36 11.99 XMM-NEWTON
4XMM J173109.1-184045 17 31 09.12 -18 40 45.12 12.15 XMM-NEWTON
4XMMs J173109.1-184045 17 31 09.12 -18 40 45.12 12.15 XMM-NEWTON
69 2CXO J173109.3-184041 17 31 09.31 -18 40 41.88 12.16 CHANDRA
CXOGSG J173109.3-184040 17 31 09.31 -18 40 40.44 12.18 CHANDRA
70 4XMM J173200.7-183841 17 32 00.77 -18 38 41.64 12.18 XMM-NEWTON
71 CXOGSG J173056.2-184352 17 30 56.26 -18 43 52.68 12.50 CHANDRA
2CXO J173056.2-184352 17 30 56.23 -18 43 53.04 12.50 CHANDRA
72 4XMM J173057.4-184259 17 30 57.50 -18 42 59.76 12.71 XMM-NEWTON
4XMMs J173057.4-184259 17 30 57.43 -18 42 59.76 12.73 XMM-NEWTON
73 4XMM J173102.7-184110 17 31 02.71 -18 41 10.68 12.88 XMM-NEWTON
4XMMs J173102.6-184110 17 31 02.69 -18 41 09.96 12.90 XMM-NEWTON
74 4XMM J173209.9-190128 17 32 09.96 -19 01 28.92 13.19 XMM-NEWTON
4XMMs J173210.0-190129 17 32 10.03 -19 01 28.92 13.20 XMM-NEWTON
75 4XMM J173054.1-184255 17 30 54.14 -18 42 55.08 13.42 XMM-NEWTON
4XMMs J173054.0-184254 17 30 54.07 -18 42 54.00 13.44 XMM-NEWTON
76 4XMMs J173109.6-190138 17 31 09.62 -19 01 39.00 13.92 XMM-NEWTON
77 4XMM J173057.0-190044 17 30 57.05 -19 00 44.28 15.10 XMM-NEWTON
4XMMs J173056.9-190044 17 30 57.00 -19 00 44.28 15.11 XMM-NEWTON

Known Radio, Optical and UV Sources

# Source Name R.A. (J2000) Dec. (J2000) Offset (') Database Table
1 NVSS J173147-185045 17 31 47.59 -18 50 44.88 1.46 NVSS
TGSSADR J173147.5-185045 17 31 47.50 -18 50 45.96 1.46 GMRTAS150M
2 NVSS J173204-184920 17 32 04.70 -18 49 21.00 5.38 NVSS
3 NVSS J173120-185160 17 31 20.11 -18 52 00.12 5.57 NVSS
4 KS Oph 17 31 29.83 -18 55 19.20 6.02 GCVS
5 PSR J1731-1847 17 31 17.59 -18 47 33.00 6.33 ATNFPULSAR
6 NVSS J173152-185628 17 31 52.30 -18 56 27.96 6.85 NVSS
7 NVSS J173211-185246 17 32 11.21 -18 52 46.92 7.40 NVSS
8 PPM 233185 17 31 14.45 -18 45 42.12 7.87 PPM
9 NVSS J173209-184506 17 32 09.31 -18 45 06.84 8.10 NVSS
10 NVSS J173205-184326 17 32 05.11 -18 43 27.12 8.55 NVSS
TGSSADR J173205.2-184322 17 32 05.21 -18 43 23.16 8.62 GMRTAS150M
11 NVSS J173215-185407 17 32 15.50 -18 54 07.92 8.87 NVSS
12 NVSS J173138-183820 17 31 38.71 -18 38 20.04 11.74 NVSS
13 PGCC G7.05+8.18 17 31 32.11 -18 38 27.96 11.83 PLANCKGCC
TGSSADR J173230.9-184254 17 32 31.01 -18 42 55.08 13.58 GMRTAS150M
14 NVSS J173231-184249 17 32 31.30 -18 42 50.04 13.69 NVSS
15 NVSS J173229-183902 17 32 28.99 -18 39 02.16 15.63 NVSS

Penn State University Goddard Space Flight Center Swift