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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

19694 results found.

  1. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  2. Swift Detection of probable new Swift SGR J1555.2-5402
  3. GRB 210529A: GECAM detection
  4. Fermi GRB 210601A: Global MASTER-Net observations report
  5. GRB 210529B: DDOTI Upper Limits on the Afterglow
  6. Fermi GRB 210529B: Global MASTER-Net observations report
  7. GRB 210528B: DDOTI Upper Limits on the Afterglow
  8. GRB 210528B: MITSuME Akeno optical upper limits
  9. GRB 210527A: Swift/UVOT Observations
  10. GRB 210527A: GIT optical upper limit
  11. GRB 210527A: MITSuME Akeno optical upper limits
  12. GRB 210527A: RATIR Optical and NIR Observations
  13. GRB 210527A: Enhanced Swift-XRT position
  14. GRB 210527A: Swift-XRT observations
  15. GRB 210306A: LBT observations of the likely host galaxy
  16. ZTF21aayokph (AT2021lfa): LBT optical observations
  17. Fermi GRB 210524B: DDOTI Upper Limits on the Afterglow
  18. IPN triangulation of GRB 210524A
  19. GRB 210522A: GECAM detection
  20. ZTF21aayokph (AT2021lfa): continued Assy optical observations
  21. GRB 210520A: Tiled Swift observations
  22. GRB 210517A: KCT optical upper limit
  23. Fermi trigger No 643065622: Global MASTER-Net observations report
  24. GRB 210518.889: DDOTI Upper Limits on the Afterglow
  25. Fermi-LAT Gamma-ray Observations of IceCube-210516A
  26. IceCube-210516A: No significant detection in HAWC
  27. GRB 210517A: Swift/UVOT Upper Limits
  28. GRB 210515C: Swift/UVOT Upper Limits
  29. GRB 210517A: VLT/X-shooter optical afterglow and redshift
  30. GRB 210517A: Enhanced Swift-XRT position
  31. GRB 210517A: Swift detection of a burst
  32. GRB 210514A: Swift/UVOT Upper Limits
  33. AMON IC_HAWC NuEm-210515A / NuEm-210515B : No neutrino counterpart detected with ANTARES
  34. GRB 210515C: Swift-XRT refined Analysis
  35. GRB 210514A: Swift-XRT refined Analysis
  36. GRB 210514A: Enhanced Swift-XRT position
  37. GRB 210512.786: DDOTI Upper Limits on the Afterglow
  38. Short GRB 210323A: likely host galaxy detection
  39. GRB 210511B: DDOTI Upper Limits on the Afterglow
  40. IPN triangulation of GRB 210427A
  41. GRB 210511B: Fermi GBM observation
  42. Fermi GRB 210510A: DDOTI Upper Limits on the Afterglow
  43. IceCube-210510A: DDOTI Upper Limits
  44. GRB 210509A: RATIR Optical and NIR Upper Limits
  45. GRB 210509A: Swift/UVOT Upper Limits
  46. GRB 210509A: Swift-BAT refined analysis
  47. GRB 210509A: Enhanced Swift-XRT position
  48. GRB 210509A: Swift-XRT observations
  49. HAWC-210507A: No neutrino counterpart candidates in ANTARES search
  50. Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
  51. GRB 210506A: Swift-XRT observations
  52. Alert from the HAWC Burst Monitor HAWC-210507A
  53. HAWC GRB 210507.443: DDOTI Upper Limit
  54. GRB 210506A: Nanshan/NEXT optical upper limit
  55. GRB 210506A: TNG NIR upper limits
  56. ZTF21aayokph (AT2021lfa): Mondy and Koshka observatory optical observations
  57. Lowell Discovery Telescope Observations of ZTF21aayokph (AT2021lfa)
  58. ZTF21aayokph (AT2021lfa): Assy optical observations
  59. GRB 210506A: Swift ToO observations
  60. ZTF21aayokph (AT2021lfa): Nanshan/NEXT optical upper limit
  61. GRB 210504A: Lowell Discovery Telescope optical observations
  62. GRB 210504A: VLT X-shooter redshift
  63. GRB 210504A: Swift-XRT refined Analysis
  64. DDOTI Observations of ZTF21aayokph (AT2021lfa)
  65. GRB 210504A: MITSuME Akeno optical upper limits
  66. Fermi GRB 210503A: DDOTI Upper Limits on the Afterglow
  67. GRB 210504A: Swift/UVOT Detection
  68. GRB 210504A: Swift detection of a burst
  69. Swift Detection of MAXI J1803-298 including an optical counterpart
  70. GRB 210424B: MITSuME Akeno optical upper limits
  71. GRB 210430A: Swift detection of a burst
  72. Delayed GRB GCN Notices from Swift
  73. Fermi GRB 210427A: Global MASTER-Net observations report
  74. GRB 210420B: Assy optical observations
  75. GRB 210424.694: DDOTI Upper Limits on the Afterglow
  76. GRB 210420B: follow-up photometry of optical afterglow at INASAN/Simeiz
  77. GRB 210420B: Zeiss-1000 of Koshka optical observations
  78. GRB 210421B: Swift-XRT observations
  79. GRB 210420B: continued Tautenburg observations
  80. GRB 210421A: GECAM detection
  81. GRB 210421A: Swift/UVOT Upper Limits
  82. GRB 210420B: follow-up photometry of the optical afterglow at Konkoly
  83. GRB 210421A: MITSuME Akeno optical upper limits
  84. GRB 210421B: Swift ToO observations
  85. GRB 210419C: Swift/UVOT Upper Limits
  86. GRB 210421A: Enhanced Swift-XRT position
  87. GRB 210420B: RATIR Optical and NIR Observations
  88. GRB 210420B: Tautenburg observations
  89. GRB 210420B: Swift/UVOT Detection
  90. GRB 210413B: MITSuME Okayama optical upper limits
  91. GRB 210419C: MITSuME Akeno optical upper limits
  92. GRB 210420B: DDOTI Detection of the Afterglow
  93. GRB 210421A: DDOTI Upper Limit
  94. GRB 210420B: Multiband photometry from NOT
  95. GRB 210420B: Montarrenti Observatory optical afterglow detection
  96. GRB 210421A: Swift detection of a burst
  97. GRB 210420B: Optical observations
  98. GRB 210420B: MASTER optical counterpart detection
  99. GRB 210419C: RATIR Optical and NIR Upper Limits
  100. GRB 210419C: Montarrenti Observatory Upper Limit

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